Weak points on turbo K20A3

[gtolio]

What's up guys.

As some of you know, I'm currently running a bone stock (head and block) K20A3 with a 60-1 Turbonetics Cybernation kit. The car is currently making 322whp/268tq at 8.5-9lbs of boost. I have the fuel cutoff set at 7600rpm (8k readout on the stock tach), because I'm concerned with the stock valvetrain keeping up beyond that.

What I'm wondering, from the people who actually know and HAVE EXPERIENCE, is what would the weak points of that motor will be if I was to turn the boost up (10-12 range) and update the tune. I want to know so that we can plan the tune around these issues as much as possible.

It is my opinion and has been my experience that the A3 is a highly underrated motor. People regularly say that they can't handle more than 300whp, but I have been doing that all day for 4 years with no issues (recent compression test came up fine) To me, it's all in the tune. I have a feeling that a lot of people have blown them because of bad tunes or other issues

If/when this thing blows up, I'll do a K24A1, but I want to see what it can do in the mean time, so please spare me the "just swap it" comments. I'm well aware of what other K-series motors can do.

Sorry for the dissertation, just wanted to give as much info as possible.

[AUTiger]

the usual response and past results have shown that it is usually the rods that are the weak link. I watched Ebizzle blow his motor at the track with 338hp on his a3. The rod made a big a$$ hole in the block.

[gtolio]

the usual response and past results have shown that it is usually the rods that are the weak link. I watched Ebizzle blow his motor at the track with 338hp on his a3. The rod made a big a$$ hole in the block.

I assume the root cause was the rods themselves and not the rod bearings? What was he revving to? Was there any sign of detonation?

[superchargedk20]

What type of dyno were u tuned on?

[gtolio]

What type of dyno were u tuned on?

Dynojet

[MugenReplica]

Shoot Tai from Corsport a PM. He was running pretty much exactly what you are asking, had a good tune, and EVENTUALLY (not as fast as other did) blew the a3, but it was around quite a long time that way from what I recall. I'm sure he'll be able to answer most of your questions.

[sleepy ep3]

Rods, rod bolts, valve springs.
You're welcome

[Tortoise]

Valvetrain is deff a weak point on a3s....I blew my stock motor at 39000 miles after having the hondata reflash for about a year and a half. Junk

[ebizzle361]

I'm unsure of any detonation. I am sure that it ran awesome at 307hp for a while, then we put meth on it and retuned it and made the power stated above and didnt run for very much longer after that. I think the rev limit was set at 7600, if that. Dont really recall. But it ran hard after the tune. Then slung a rod. Didn't inspect too much beside the fact that a rod broke. I say, if you have plans for that k24a1, then turn the boost up and have fun. Do some testing for yourself and see what the results are. maybe they'll be better for you. Then when it happens, which I ASSUME it will, put that a1 in there and have some more fun. Good luck and let us know what happens!

[gtolio]

Thanks guys.

[Draw7Seven]

Yeah by the time you upgrade the number of internals in the A3 that would need attention, you'd be at least halfway to the price of a K24a1.

[gtolio]

I'm not going to upgrade the A3 long block when I can have a K24A1 in my car for $600. The plan is just to know where the weak points are so that we have an accurate assessment of what it can handle going forward and to know what kind of things to avoid in terms of the tune.

[USAF EP3]

Push it man, if we got these old school D16 fuckers pushing over 300whp with stock bottom ends and slightly built heads why can't the A3 do it too?

[04EP3Hatch]

i think 10-12psi should have you set, keep your rev limit or hell lower it if your worried and go for gold, if you have a good tuner than you have nothing to worry about, just make sure you stress to him you want to keep it conservative lol

[gtolio]

i think 10-12psi should have you set, keep your rev limit or hell lower it if your worried and go for gold, if you have a good tuner than you have nothing to worry about, just make sure you stress to him you want to keep it conservative lol

He's pretty good about knowing where the limits are. I think it'll be fine too.

[sleepy ep3]

i think 10-12psi should have you set, keep your rev limit or hell lower it if your worried and go for gold, if you have a good tuner than you have nothing to worry about, just make sure you stress to him you want to keep it conservative lol
Little secret....
More boost, less timing.
Anyway, why do we constantly post on things that are so obvious? To increase post count? The theory to making the Ep3 move faster is not rocket science. Stock boosted a3, or a swap. Ta-da. Either way, you have to spend money to make power. People would rather debate about 100 different ways to do it, rather than just make a decision. There are numerous(!) threads on ephatch for every single type of setup u could possibly want, and if all else fails, there is k20a.org. Not trying to be that guy, but how long should we debate over the weak points of the k20a3? Really?

[playap07]

Push it man, if we got these old school D16 fuckers pushing over 300whp with stock bottom ends and slightly built heads why can't the A3 do it too?

lmao you a wild man!


Little secret....
More boost, less timing.
Anyway, why do we constantly post on things that are so obvious? To increase post count? The theory to making the Ep3 move faster is not rocket science. Stock boosted a3, or a swap. Ta-da. Either way, you have to spend money to make power. People would rather debate about 100 different ways to do it, rather than just make a decision. There are numerous(!) threads on ephatch for every single type of setup u could possibly want, and if all else fails, there is k20a.org. Not trying to be that guy, but how long should we debate over the weak points of the k20a3? Really?

Because knowlege is power and if you can make a stock a3 push 400hp for a bit while making sure you keep the strain down on weak componets thats some big up props! I too wouldnt mind seeing or pushing the crap out of my a3 just to see if she has the balls but the point is trying to find the weak points and maybe overcome hopefully.?.?.

Something i have learned over the years in diff motors. Some motors can actually handle some high ass hp with stock internals. The thing that kills those certain type of motors is how high the tq level is. If the tq was kept down to a safe level the engine could maintain this hp level and be safe for a dd. I AM NOT SURE IF OUR K20A3 CAN DO THIS. So do not think i am tryin to say our k series motors can. If someone wanted to do an experiment, more power too them. I am subscribed! Just knowing the weak points of your motor is great knowlege and it helps to build awarness.

Just my silly 2 cents for ya

[gtolio]

Little secret....
More boost, less timing.
Anyway, why do we constantly post on things that are so obvious? To increase post count? The theory to making the Ep3 move faster is not rocket science. Stock boosted a3, or a swap. Ta-da. Either way, you have to spend money to make power. People would rather debate about 100 different ways to do it, rather than just make a decision. There are numerous(!) threads on ephatch for every single type of setup u could possibly want, and if all else fails, there is k20a.org. Not trying to be that guy, but how long should we debate over the weak points of the k20a3? Really?

Don't give me that. I don't give a shit about post count, and my EP3 is already quick, so I don't need your lecture.

The reason is because just about NO one tries to do anything with the stock A3 and comes back with useful info. There are probably 100 threads about each and every K24 out there as well as the A2, A, Z1, Z3 and so on, but there are pretty much no threads with actual first hand information about why an A3 goes when it does, because no one tries to do anything with it, and if they do, they don't push it while trying to preserve it. On top of that, there's probably 10,000 posts of people dogging on the motor because regurgitated BS they heard from a friend of a friend who probably had a shitty tune in the first place. There are so many shit threads posted day in day out about questions that were answered last week and you come after this one where I am trying to build useful information.

I don't need someone and I never asked for someone to hold my hand or make a decision for me, so come off it. I asked specifically for the weak links in the motor from people that have actually tried it because my tuner asked for the information so that he could most effectively work around potential issues. If you don't have anything productive to add, then please take it somewhere else. Thanks.

[Lucid Moments]

Thereused to be threads out there about the A3 but they got lost due to time and server crashes. Lots of people tried lots of things with the a3 before the k24 swaps were common. I don't remember all the details but nobody got much beyond where you are.

But give it a shot and you might find something new. And I'm not trying to be a smartass there I really mean it. If people don't try new shit then nobody will ever learn anything.

My personal opinion is that you are going to find that the rods are not strong enough to handle more than you are giving them but it seems like you are prepared for that.

[sleepy ep3]

Don't give me that. I don't give a shit about post count, and my EP3 is already quick, so I don't need your lecture.

The reason is because just about NO one tries to do anything with the stock A3 and comes back with useful info. There are probably 100 threads about each and every K24 out there as well as the A2, A, Z1, Z3 and so on, but there are pretty much no threads with actual first hand information about why an A3 goes when it does, because no one tries to do anything with it, and if they do, they don't push it while trying to preserve it. On top of that, there's probably 10,000 posts of people dogging on the motor because regurgitated BS they heard from a friend of a friend who probably had a shitty tune in the first place. There are so many shit threads posted day in day out about questions that were answered last week and you come after this one where I am trying to build useful information.

I don't need someone and I never asked for someone to hold my hand or make a decision for me, so come off it. I asked specifically for the weak links in the motor from people that have actually tried it because my tuner asked for the information so that he could most effectively work around potential issues. If you don't have anything productive to add, then please take it somewhere else. Thanks.

Do you not read, or know how to search? Look on here, and there are threads titled "K20a3 went kabloowie, time for a swap" and many variations thereof. In those threads, they explain what happened, and what broke. Its pretty much common knowledge of why the k20A3 is junk for making power efficiently, (financially and otherwise) but I guess you're one of those people

NO.... People HAVE tried to make power with it and have either:

A: Blew the K20A3 the fuck up
or
B: Spent way too much on making less than 300hp, thats not as reliable as a better / different motor with the same horsepower.

Don't get butt hurt because your a troll, asking for info that can either be found by Google, or by searching Honda forums. You could easily search for "best k20 swap" and found out why people think that way just by reading the results, and why people don't recommend the a3.

LOL, you're such a funny guy, I like you. :msmooch:

[superchargedk20]

Little secret....
More boost, less timing.
Anyway, why do we constantly post on things that are so obvious? To increase post count? The theory to making the Ep3 move faster is not rocket science. Stock boosted a3, or a swap. Ta-da. Either way, you have to spend money to make power. People would rather debate about 100 different ways to do it, rather than just make a decision. There are numerous(!) threads on ephatch for every single type of setup u could possibly want, and if all else fails, there is k20a.org. Not trying to be that guy, but how long should we debate over the weak points of the k20a3? Really?
my favorite pointless threads will always be " how can I make my ep3 faster".. and my number 1 pointless thread of all time " which intake should I buy"

[AKEP]

Do you not read, or know how to search? Look on here, and there are threads titled "K20a3 went kabloowie, time for a swap" and many variations thereof. In those threads, they explain what happened, and what broke. Its pretty much common knowledge of why the k20A3 is junk for making power efficiently, (financially and otherwise) but I guess you're one of those people

NO.... People HAVE tried to make power with it and have either:

A: Blew the K20A3 the fuck up
or
B: Spent way too much on making less than 300hp, thats not as reliable as a better / different motor with the same horsepower.

Don't get butt hurt because your a troll, asking for info that can either be found by Google, or by searching Honda forums. You could easily search for "best k20 swap" and found out why people think that way just by reading the results, and why people don't recommend the a3.

LOL, you're such a funny guy, I like you. :msmooch:

hell yeah too many disappointed people were on here once upon a time trying to spend 10K on a setup and not put any rods/pistons in, just to pop the motor. its usually rods and anything connected to them, or rods and everything connected to them. put in arp bolts, rods will snap, put in forged rods, blow up pistons. and forged rods and pistons, crankwalk.

so you put in k20a2 crank and forged internals. what is that like 2k-2.5k on just the bottom in parts? just to make 500hp? i'll take my k24a1 and be done. a3 is junk. only good for a cheap k swap or an untapped forged block.

have fun.

[MugenReplica]

http://troglopundit.files.wordpress.com/2011/11/yoda-hulk-anger-leads-to-the-dark-side.jpg?w=500&h=345

[Ba82Ep3]

On top of that, there's probably 10,000 posts of people dogging on the motor because regurgitated BS they heard from a friend of a friend who probably had a shitty tune in the first place...

This is the number one reason you should do it... to show it can be done.

Kevin's post holds merit. Single dingle (d15/16) owners have spent YEARS trying to prove to the community that boosted power can be reliable on the engines so many people threw away years ago for more popular swaps.

Sound familar?

One can consider the tunability of KPro (or any standalone for a k series for that matter) an asset that d/f series owners would have killed for 20 years ago. Even moreso... the knowledge and EXPERIENCE that comes with TIME spent finding out what works... and what doesnt (hole in the block).

Sound familar?

So... heres to the daily beaten k20a3. :shots:

Admittedly mine isnt boosted yet but... every time i turn the key im reminded of how wrong so many people are/have been over the reliability of the k20a3 (small rods and mains take a beating NA as well yanno?). Anyone that knows me/how i drive, will attest to the durability of what is under my hood. But they will also tell you how much time i take tuning and maintaining my shit box. Its all part of it.

If it were me, i would tune at 15psi with less advance than 10psi and more advance (and mind you my boost tuning is based mostly on SC'd setups, so feel free to tear this statement apart). Let the boost do its job without excess advance. The only bad thing about this is (and this will be more noticeable if he tunes each cam angle, which in itself can be a roll of the dice with every pull)... some cam angles will work best with more advance and others will work best with more boost. So, if you tune around complete reliability (less advance), depending on the turbo used, i can imagine the engine being extremely weak off the snail. Either way its going to be a compromise...

[MugenReplica]

Not a K20a3, but I've always thought a K20a2/z1/z3 bottom end with a K24a1 head would be an amazing setup to play around with....

[gtolio]

every time i turn the key im reminded of how wrong so many people are/have been over the reliability of the k20a3

This is the reason for the thread. I think that a large amount of the information about how much various K-series motors can take, which is presented day in and day out as fact, is inaccurate. People told me for years before I turbo'd my car (and people still tell me today) that "there is absolutely no way" a stock A3 can handle over 300whp. Well guess what, I'm at 322 and have been for 4 years now. People say the rods are weak on the K24A4 because they are small (which is correct). I have a friend that ran that motor for over two years at over 500whp with zero issues.

I have a perfectly good motor in my car right now. I'm not looking to swap (right now anyways) unless something does go wrong. I'm not asking what the best way to get to X amount of horsepower is. It's clearly a different motor. If I wanted to make 500+, I'd know exactly how to do it already. All I'm asking is, how much can this one take. I'm sorry if that rubbed anyone the wrong way.

[Ba82Ep3]

Not a K20a3, but I've always thought a K20a2/z1/z3 bottom end with a K24a1 head would be an amazing setup to play around with....

Thats basically what i have... minus the crank and rods... and the k24a1 head has flipped pin VTEC. The only thing im missing is another 1k 'safe' rpm VS an a2/z1/z3 complete bottom end (which is debatable). The plans were to boost (10psi), so i wasnt concerned about that tho... power to 7500rpm was all i cared about.

[Ba82Ep3]

http://troglopundit.files.wordpress.com/2011/11/yoda-hulk-anger-leads-to-the-dark-side.jpg?w=500&h=345



dis sh!t=funnY!

[gtolio]

hell yeah too many disappointed people were on here once upon a time trying to spend 10K on a setup and not put any rods/pistons in, just to pop the motor. its usually rods and anything connected to them, or rods and everything connected to them. put in arp bolts, rods will snap, put in forged rods, blow up pistons. and forged rods and pistons, crankwalk.

so you put in k20a2 crank and forged internals. what is that like 2k-2.5k on just the bottom in parts? just to make 500hp? i'll take my k24a1 and be done. a3 is junk. only good for a cheap k swap or an untapped forged block.

have fun.

Agreed totally. I've never thought that building an A3 was worth it in any shape or form. With what it would cost, there are FAR better options out there. Upping the boost costs me nothing. If I get to 350, I'll be happy with it. If I were going for 500 it would be on a K24A1, head studs and turn up the boost, call it a day.

The fact of the matter is, I'm setting up my car for road racing and I don't need or want that much power. I'm going to run boost by gear as well, so I think that will help. I'll probably lower the boost in 1st and 2nd, keep it the same in 3rd, and raise it in 4th and 5th.

[04EP3Hatch]

see this is where i side with gtolio, i beleive it can be done WITH a competent tuner that knows a thing or two about an A3. Is the A3 the runt of the litter? yes, does that mean its garbage.. no. it is to the people that dont have the will to research/try the process to make the power and make it well. Look at me, i am FLIRTING with the disaster 300whp zone, im probably over it on a cold day, and i beat the HELL out of my car, literally just now on the way home from my g/f's i did a pull to 160mph, practiced my launches for when i go to the track, and had some other spirited fun. i do this shit on a regular basis with my car and it keeps coming back for more. but back on topic, gtolio, go for it. like i said i'd attempt 12psi first and go from there, i know you made over 300 by a decent amount and another 2psi will probably yeild you another 30-40 if the setup allows. and make sure the tuner you are using is damn good one and make sure you tell him "listen, were really in uncharted territory here" so he can keep it easy on the advance and go from there, personally invest in some safety mod's, a small water/meth kit, e85 fuel, etc.

[Draw7Seven]

see this is where i side with gtolio, i beleive it can be done WITH a competent tuner that knows a thing or two about an A3. Is the A3 the runt of the litter? yes, does that mean its garbage.. no. it is to the people that dont have the will to research/try the process to make the power and make it well. Look at me, i am FLIRTING with the disaster 300whp zone, im probably over it on a cold day, and i beat the HELL out of my car, literally just now on the way home from my g/f's i did a pull to 160mph, practiced my launches for when i go to the track, and had some other spirited fun. i do this shit on a regular basis with my car and it keeps coming back for more. but back on topic, gtolio, go for it. like i said i'd attempt 12psi first and go from there, i know you made over 300 by a decent amount and another 2psi will probably yeild you another 30-40 if the setup allows. and make sure the tuner you are using is damn good one and make sure you tell him "listen, were really in uncharted territory here" so he can keep it easy on the advance and go from there, personally invest in some safety mod's, a small water/meth kit, e85 fuel, etc.

This guy knows. He's the only other one to really WANT the longevity from a 300+ A3 setup.

[AKEP]

The K-series anything is a good motor, honda really put some effort into it's design. The A3 is no exception. I beat on mine for 105k with stock EVERYTHING minus KPro.

I'm not sure how much QA went into the A3 assembly when it was at plant, or how much of it is put together by hand, but it's left some people with barely 300hp, or under 350.

Now when you take in to account that these were probably built with an unopened block, this motor isn't going to make much more power.

300hp is a lot of good street power too, theres nothing wrong with 300hp, thats enough to spin 3rd on some cheap tires. the 300hp barrier might be a tq problem more than a hp problem. Thats usually the cause of ANY motor explosion not related to detonation.

The A3 block is great, just needs higher tolerances for everything in it. which is why people opt for a2 internals, at least the crank with forged rods and pistons, oil pump and pan. we already know an A2 can make over 600hp (record right now is somewhere in there) in an unopened block. but if your goal is to not open the a3 and push 350-400hp, good luck.

For the cost of a k24a1, you are getting 20lbs or so more tq and a higher flowing 2 lobe head and a stronger bottom end that will just about garantee you 500hp unopened. For the price, you just can't beat it. even if you got free a2 internals, working to put those in the a3 vs not touching an a1. It's just easier and more reliable to make power with. You save your turbo by allowing more CFM of flow, which in terms means more power for the same amount of boost. Your turbo wont be spooling its ass off to stuff this air in an engine that wont flow.

It's up to you. You can do a small build just to make a reliable 300 no bullshit, but why waste your money opening the a3 up when you can just toss in a k24a1 and be even better off.

[Euro-Yellow-Ep3]

I think with a good tune, you should be able to run 12 psi. keep us updated

[Ba82Ep3]

I also agree with AKEP. Ive been down the k24a1 road and it is a hands down better platform to start with. But i also realized the TQ was more than i *needed*.

The short gear 6 speed with the 2 liter is more managable IMO than the long gear with the 2.4. Thats a preference though. One day ill get that 2.2 finished on the same trans... and i think i will have found my happy place.

[sleepy ep3]

Youre going to do what u want anyway. Mod the a3, have fun, awesome.
As a daily driven car, I prefer the k24 over the old a3 any day. The extra torque allows you to barely push it to get going, and you can just putter about without any fuss. As you can get a good k24 for around $5-600 bucks, I wouldn't waste my time on an a3

[USAF EP3]

Haters are going to hate


http://youtu.be/2YXjatdlJNQ

Stock B18 and D16 rods:

5905

Stock A3 rods:

5906

If the D rods can hold over 300 horses as proven in the video above, with high boost for that matter, then there is no excuse why the A3 can't do it too without blowing up. I think it's a laziness from the tuners to just point the customers to a "better" platform (no bigger does not mean better lol), because they don't want to sit for a whole day trying to extract every available power from the K20A3.

Think about it, american cars don't bother with small displacement high output. It easier for them to just drop a big 5.7L and make 400 horses than put a 2.4L four pot with a big turbo and tune the hell out of it to make the same 400 horses. Quit bullying the guy into getting a bigger engine, he'll do whatever the hell he wants and I hope he proves everyone here wrong on the potential of the A3.

Conclusion: D16's do it, you say A3 can't, I'm calling the :bs:

[sleepy ep3]

[SIZE=4]

Think about it, american cars don't bother with small displacement (and generally are faster with less $$$ invested) *It's* easier for them to just drop a big motor and make real world drive-able horsepower that's easier to control under acceleration, than to put a 2.4L four pot with a big turbo and rev the living hell out of it to make any power, and costs more to develop for multiple reasons. Your not bullying the guy into getting a bigger engine, your just telling him the facts. I hope he proves everyone here right yet again on the potential of the A3.

Conclusion: Why don't most of the cars that see track or drag duty use these motors? Because they would rather be smart and use whats right, rather than trying to be cool and cater to the 1%

Fixed. :loco:

BTW, have you actually ever compared the stock a3 rods to a d series, b series and aftermarket rod side by side, other than pictures, and looked at the physical difference? Anyway, I already told him to go his own way. I have no stake in the matter, so I don't care, :tehe: I'm just saying my .02. Your not a communist are you? :mrolleyes:

It all falls down to the age old saying:

JUST BECAUSE YOU CAN DO SOMETHING DOESN'T MEAN YOU SHOULD

[USAF EP3]

Fixed. :loco:

BTW, have you actually ever compared the stock a3 rods to a d series, b series and aftermarket rod side by side, other than pictures, and looked at the physical difference? Anyway, I already told him to go his own way. I have no stake in the matter, so I don't care, :tehe: I'm just saying my .02. Your not a communist are you? :mrolleyes:

It all falls down to the age old saying:

JUST BECAUSE YOU CAN DO SOMETHING DOESN'T MEAN YOU SHOULD

Don't see anywhere in my post that would lead you to infer a question as to whether I was a communist or not. I certainly don't consider myself one.

I've never compared the rods in person only because I haven't been able to get a hold of a set of B/D rods, but just for this thread's sake (and your challenge) I will go out this week and buy a set.

Also, I by no means am putting down american horsepower. I own over 1000 shares in Ford Motor Co., and I will admit I am proud to say that they are doing a great job by adding their version of VVT to the new 5.0 engine and using the technology smaller displacement engines have been using for years to put out higher horsepower per litre. In that sense I feel I made a great investment with them (owned since 2009).

My point I was trying to make is that if you have a car with an engine already in it and you want to see how far it'll take you, then do it. You'll never really know the limit if you never try and that's what the pioneers of tuning do.

No need to call me crazy (or communist for that matter) or go and change what I said into something completely different, I would appreciate if you could respect other's opinions and views instead of imposing your own. If anything I would ask if YOU were the communist, you want everyone to have the same engine that works so well for you.

[sleepy ep3]

Don't see anywhere in my post that would lead you to infer a question as to whether I was a communist or not. I certainly don't consider myself one.

I've never compared the rods in person only because I haven't been able to get a hold of a set of B/D rods, but just for this thread's sake (and your challenge) I will go out this week and buy a set.

Also, I by no means am putting down american horsepower. I own over 1000 shares in Ford Motor Co., and I will admit I am proud to say that they are doing a great job by adding their version of VVT to the new 5.0 engine and using the technology smaller displacement engines have been using for years to put out higher horsepower per litre. In that sense I feel I made a great investment with them (owned since 2009).

My point I was trying to make is that if you have a car with an engine already in it and you want to see how far it'll take you, then do it. You'll never really know the limit if you never try and that's what the pioneers of tuning do.

No need to call me crazy (or communist for that matter) or go and change what I said into something completely different, I would appreciate if you could respect other's opinions and views instead of imposing your own. If anything I would ask if YOU were the communist, you want everyone to have the same engine that works so well for you.
Lol, I was saying communist because it seems like all those opposed to the idea of a built a3 are ridiculed, and shot down. Personally, I wouldn't care if you were lol. I'm not saying that he couldn't mod the a3. I modded mine in the beginning, and it was fun. What I am saying (and many others are trying to say) is that for making 3-350 hp, there are better choices, that will make the power without as much stress. It's a debate, and there is no right answer, just opinions. But when people that have been there before, and done a lot of research, blown up motors, and seen what works well and what doesn't speak up, and offer opinions, I usually listen, and at the minimum, give it some thought.

I changed what you said out of humor, and you didn't get it. Chill out, go change your sanitary towel, and let's all be friends again. :)

[MugenReplica]

Long forgotten information about the K20a3 is that it makes more power than both the F20C and the K20a2 below 6000rpms, so not great for peak power, but pretty damn good for mid range.

From back in 2003.....
While I was looking through Comptech's website to look for new products, I found some dyno charts of the 02' Civic Si (K20A3), 02 RSX-S (K20A2), and the S2000 (F20C). Since I was bored, I decided to plot the charts together and do some simple analyses. The numbers come directly from Comptech's published numbers for the cars in stock form.

In this first graph, I plot the horsepower for all 3 engines. The blue line is the K20A3 (02 Si), the red line is the K20A2 (RSX-S), and the yellow line is the F20C (S2000). What struck me was the fact that the K20A3's horsepower is higher than the K20A2 and the F20C until about 6000RPMs.

http://sohc.vtec.net/gilbert/K20_comp/horsepower.gif

We can get a better idea of the horsepower difference by looking at the following graph. I plot the Delta (i.e. the difference between the engine horsepower). The blue line is the horsepower difference between the K20A3 and the K20A2 (i.e. K20A3 - K20A2). The red line is the difference between the K20A3 and the F20C and the yellow line is the difference between the F20C and the K20A2. A positive number indicates that the reference engine is producing more power at a given RPM. For instance, the blue line shows that the K20A3 produces more power than the K20A2 up until 6000RPMs. Similarly, the K20A3 produces more power than the F20C up until about 5800RPMs. Notice that the S2000 produces more power than the RSX-S except for a few spots.

http://sohc.vtec.net/gilbert/K20_comp/horsepower_delta.gif

The torque graphs show a similar trend.
http://sohc.vtec.net/gilbert/K20_comp/torque.gif
http://sohc.vtec.net/gilbert/K20_comp/torque_delta.gif

So at about 6000RPMs, there is a definite change between the power characteristics of the K20A3 as compared to the K20A2 and F20C. I've heard that the Civic Si has a restrictive intake and exhaust. Another obvious problem is the fact that the Civic Si only has 6800RPMs versus the 8000RPM and 9000RPM limits of the RSX-S and S2000 respectively.

What happens when we add some modifications? I used Comptech's data for a 02 Civic Si with their intake, header and exhaust combo to compare it to the stock S2000 and RSX-S. See the next 4 graphs.

http://sohc.vtec.net/gilbert/K20_comp/horsepower_mod.gif
http://sohc.vtec.net/gilbert/K20_comp/horsepower_delta_mod.gif
http://sohc.vtec.net/gilbert/K20_comp/torque_mod.gif
http://sohc.vtec.net/gilbert/K20_comp/torque_delta_mod.gif

To be fair, the dyno numbers are not from an independent source so we need to take them with a grain of salt. However, we see that the RPM point at which the K20A3 is overtaken by the other two engines gets pushed out by one to two hundred RPMs.

The only thing we are missing is the improved redline. According to Hondata's website, a totally stock Civic Si with 91 octane gas and their flash upgrade produced about 10HP at the peak.

http://www.hondata.com/k20a3civicsirelease.html

What we really need to see is a dyno numbers for the Si, RSX-S and S2000 from an independent dyno. Furthermore, we need to see a dyno from the Si with the hondata flash tuned for an intake, header and exhaust.

My question: Is it possible to maintain the good low RPM characteristics of the K20A3 while simultaneously improving the high RPM characteristics? A Hondata flash seems like it would help, but a change in cams may be in order. It doesn't look like Toda makes cams for the K20A3, so it looks like we're out of luck.

Why do I ask? Simple. You can get a Civic Si for well under MSRP. My friend picked one up for $17K out the door. Compared tto a RSX-S at $24K, you have about $7K to work with (assuming that you like the look of the Si ;-)). Anyway, if Toda made their engine kit for the K20A3 (or if you could use the K20A kit) and sold it for $2400, you'd still have $4.6K to work with. Is it possible to make a Civic Si perform as well as a similarly modded RSX-S?

[Blah1219]

The K-series anything is a good motor, honda really put some effort into it's design. The A3 is no exception. I beat on mine for 105k with stock EVERYTHING minus KPro.

I'm not sure how much QA went into the A3 assembly when it was at plant, or how much of it is put together by hand, but it's left some people with barely 300hp, or under 350.

Now when you take in to account that these were probably built with an unopened block, this motor isn't going to make much more power.

300hp is a lot of good street power too, theres nothing wrong with 300hp, thats enough to spin 3rd on some cheap tires. the 300hp barrier might be a tq problem more than a hp problem. Thats usually the cause of ANY motor explosion not related to detonation.

The A3 block is great, just needs higher tolerances for everything in it. which is why people opt for a2 internals, at least the crank with forged rods and pistons, oil pump and pan. we already know an A2 can make over 600hp (record right now is somewhere in there) in an unopened block. but if your goal is to not open the a3 and push 350-400hp, good luck.

For the cost of a k24a1, you are getting 20lbs or so more tq and a higher flowing 2 lobe head and a stronger bottom end that will just about garantee you 500hp unopened. For the price, you just can't beat it. even if you got free a2 internals, working to put those in the a3 vs not touching an a1. It's just easier and more reliable to make power with. You save your turbo by allowing more CFM of flow, which in terms means more power for the same amount of boost. Your turbo wont be spooling its ass off to stuff this air in an engine that wont flow.

It's up to you. You can do a small build just to make a reliable 300 no bullshit, but why waste your money opening the a3 up when you can just toss in a k24a1 and be even better off.

While I have my freshly OEM built a3, yall can count down the miles left on that high mileage k24a1.

[Powers]

Long forgotten information about the K20a3 is that it makes more power than both the F20C and the K20a2 below 6000rpms, so not great for peak power, but pretty damn good for mid range.

From back in 2003.....
While I was looking through Comptech's website to look for new products, I found some dyno charts of the 02' Civic Si (K20A3), 02 RSX-S (K20A2), and the S2000 (F20C). Since I was bored, I decided to plot the charts together and do some simple analyses. The numbers come directly from Comptech's published numbers for the cars in stock form.

In this first graph, I plot the horsepower for all 3 engines. The blue line is the K20A3 (02 Si), the red line is the K20A2 (RSX-S), and the yellow line is the F20C (S2000). What struck me was the fact that the K20A3's horsepower is higher than the K20A2 and the F20C until about 6000RPMs.

http://sohc.vtec.net/gilbert/K20_comp/horsepower.gif

We can get a better idea of the horsepower difference by looking at the following graph. I plot the Delta (i.e. the difference between the engine horsepower). The blue line is the horsepower difference between the K20A3 and the K20A2 (i.e. K20A3 - K20A2). The red line is the difference between the K20A3 and the F20C and the yellow line is the difference between the F20C and the K20A2. A positive number indicates that the reference engine is producing more power at a given RPM. For instance, the blue line shows that the K20A3 produces more power than the K20A2 up until 6000RPMs. Similarly, the K20A3 produces more power than the F20C up until about 5800RPMs. Notice that the S2000 produces more power than the RSX-S except for a few spots.

http://sohc.vtec.net/gilbert/K20_comp/horsepower_delta.gif

The torque graphs show a similar trend.
http://sohc.vtec.net/gilbert/K20_comp/torque.gif
http://sohc.vtec.net/gilbert/K20_comp/torque_delta.gif

So at about 6000RPMs, there is a definite change between the power characteristics of the K20A3 as compared to the K20A2 and F20C. I've heard that the Civic Si has a restrictive intake and exhaust. Another obvious problem is the fact that the Civic Si only has 6800RPMs versus the 8000RPM and 9000RPM limits of the RSX-S and S2000 respectively.

What happens when we add some modifications? I used Comptech's data for a 02 Civic Si with their intake, header and exhaust combo to compare it to the stock S2000 and RSX-S. See the next 4 graphs.

http://sohc.vtec.net/gilbert/K20_comp/horsepower_mod.gif
http://sohc.vtec.net/gilbert/K20_comp/horsepower_delta_mod.gif
http://sohc.vtec.net/gilbert/K20_comp/torque_mod.gif
http://sohc.vtec.net/gilbert/K20_comp/torque_delta_mod.gif

To be fair, the dyno numbers are not from an independent source so we need to take them with a grain of salt. However, we see that the RPM point at which the K20A3 is overtaken by the other two engines gets pushed out by one to two hundred RPMs.

The only thing we are missing is the improved redline. According to Hondata's website, a totally stock Civic Si with 91 octane gas and their flash upgrade produced about 10HP at the peak.

http://www.hondata.com/k20a3civicsirelease.html

What we really need to see is a dyno numbers for the Si, RSX-S and S2000 from an independent dyno. Furthermore, we need to see a dyno from the Si with the hondata flash tuned for an intake, header and exhaust.

My question: Is it possible to maintain the good low RPM characteristics of the K20A3 while simultaneously improving the high RPM characteristics? A Hondata flash seems like it would help, but a change in cams may be in order. It doesn't look like Toda makes cams for the K20A3, so it looks like we're out of luck.

Why do I ask? Simple. You can get a Civic Si for well under MSRP. My friend picked one up for $17K out the door. Compared tto a RSX-S at $24K, you have about $7K to work with (assuming that you like the look of the Si ;-)). Anyway, if Toda made their engine kit for the K20A3 (or if you could use the K20A kit) and sold it for $2400, you'd still have $4.6K to work with. Is it possible to make a Civic Si perform as well as a similarly modded RSX-S?

That seems like a pretty good argument if you ask me. If you buy the hondata reflash as a for now thing lets say, and later decide to get kpro hondata will give you a discount on kpro right? If so I might be willing to try out the reflash and put it on a dyno.....this is of course after I go home on leave for my 21st birthday though.

I also may be able to get my buddy whos purchasing a basic bolt on type s soon to go to the dyno afterwards with me....and if I get to know the s2k that always ends up parked next to me I may be able to get him to go to the dyno aswell (s2k just has a catback as far as I know)

[playap07]

Interesting information Mugenreplica provided. I like it.

Gtolio, If i were you and I was really serious about seeing if the a3 can push more than 300hp and 300tq, for starters i would start a case study (i think thats what its called)
what I would do is compile a list of::

k20a3s that blew
what mods
if boosted or not
thier power level (hopefully with chart if able to locate one)
type of tune
What componet failed
How did it fail?


Im willing to bet on some of the boosted a3s the drivier might have tried to go in boost in high gear low rpm and cause tremendous load on the engine. This is just my speculation but in order to find out you would have to ask that individual and hope they tell the accurate truth. I would even check other forums like clubrsx for their info. Also i would check with tuners to get their info. I remeber i used to go on evanstuning website and look at all the numbers and data he provided on the engines he tuned. alot of usefull information on there if you ask me.

[04EP3Hatch]

im going to 12psi im bored already, gtolio if i do it before you do ill report back haha

[icee753]

well if you do up the boost let us know how it goes and what the numbers are.. also what injectors are you running on you current set up?

[04EP3Hatch]

Oh I will for sure, I'm undecided on injector choice, I have Siemens 650's now and I hate the drivability of them and the idle quality but I can't afford new ID1000's so I'm gonna try and source a used set, and I'm doing everything off the wastegate. No boost solenoid/controller, so it's not like I can turn it down to 9 and say I lasted 100000 miles on 12psi lol

[sleepy ep3]

What we really need to see is a dyno numbers for the Si, RSX-S and S2000 from an independent dyno. Furthermore, we need to see a dyno from the Si with the hondata flash tuned for an intake, header and exhaust.

My question: Is it possible to maintain the good low RPM characteristics of the K20A3 while simultaneously improving the high RPM characteristics? A Hondata flash seems like it would help, but a change in cams may be in order. It doesn't look like Toda makes cams for the K20A3, so it looks like we're out of luck.

Why do I ask? Simple. You can get a Civic Si for well under MSRP. My friend picked one up for $17K out the door. Compared tto a RSX-S at $24K, you have about $7K to work with (assuming that you like the look of the Si ;-)). Anyway, if Toda made their engine kit for the K20A3 (or if you could use the K20A kit) and sold it for $2400, you'd still have $4.6K to work with. Is it possible to make a Civic Si perform as well as a similarly modded RSX-S?

I would think that the reason that the power is greater down low is because the fake vtec begins at around 2800 on the a3, to get it moving.

[USAF EP3]

I would think that the reason that the power is greater down low is because the fake vtec begins at around 2800 on the a3, to get it moving.

It's not "fake" VTEC. VTEC = Variable Valve Timing and Lift Electronic Control. Doesn't matter if it's two lobe or three lobe or any lobe. VTEC is VTEC. Also, it engages at 2200 RPMS on K24A1/4/6/8 and K20A3/Z2. Quoted from Wiki:

"VTEC was initially designed to increase the power output of an engine to 100 HP/litre or more while maintaining practicality for use in mass production vehicles. Some later variations of the system were designed solely to provide improvements in fuel efficiency."

And yes, it makes power faster below 6000RPMS because the profile for the secondary lobe is larger than the primary lobes on the three lobe VTEC engines.

[MugenReplica]

Also flips over at 2200rpms....

All that was repostings that were posted almost 10 years ago when the 02-03 Si came out.

[sleepy ep3]

It's not "fake" VTEC. VTEC = Variable Valve Timing and Lift Electronic Control. Doesn't matter if it's two lobe or three lobe or any lobe. VTEC is VTEC. Also, it engages at 2200 RPMS on K24A1/4/6/8 and K20A3/Z2. Quoted from Wiki:

"VTEC was initially designed to increase the power output of an engine to 100 HP/litre or more while maintaining practicality for use in mass production vehicles. Some later variations of the system were designed solely to provide improvements in fuel efficiency."

And yes, it makes power faster below 6000RPMS because the profile for the secondary lobe is larger than the primary lobes on the three lobe VTEC engines.
I was joking. Most people think of vtec as increasing horsepower, not improving fuel economy. Hence the "fake" word.

[lemonhead228]

Why try to push the a3 to 350 whp and worry every time you go wot... well you have plans already if it blows so why not just test it out and prove us all wrong.. they just mention swaps cuz its gonna be more reliable than the a3..

[gtimportfanatic]

if anyone were to attest to the struggles of the a3 i can testify to that.. i bought my car with 38k on it, drove it untuned with bolt ons to 50k, bought kpro.. beat on it some more .. turbo'd at 60k made 263 on 7psi, ran the car at 10psi on the street.. drove it half way across the country and back, took the turbo kit off at 75k, beat on it some more til 90k, and went vtec killer with six speed trans after that up til 106k when i pulled the motor, still strong, sold it to a friend who is gonna put it in a civic coupe. the motor is def strong in terms of taking a beating, i think the biggest thing on why people have seen soo many fuck ups is because of tuning. tuning makes everything legit and if you dont have an on point tune you're just gonna be motherfucking the motor even more and more.. seeing that the OP has been boosted for 4 years alone puts that talk to rest, and i've heard of stock blocks making excess of 380whp.. i'd say to give it a go, i know Dan is gonna try the same and see what happens

[gtimportfanatic]

Why try to push the a3 to 350 whp and worry every time you go wot... well you have plans already if it blows so why not just test it out and prove us all wrong.. they just mention swaps cuz its gonna be more reliable than the a3..

if you read the thread u would realize why.. its not to make the power its to prove that the power can be made... it's called venturing lol

[Onasty]

if you read the thread u would realize why.. its not to make the power its to prove that the power can be made... it's called venturing lol

Venturing is fun but not on a daily driver, unless you have a back up engine. I had to worry too much on my setup when i was venturing.

[lemonhead228]

if you read the thread u would realize why.. its not to make the power its to prove that the power can be made... it's called venturing lol

I did read the whole thread and I understand what he is trying to do. Of course he will make the power but how long will it last? If its my dd, I wouldn't think twice wasting my money to prove a point. Well good luck on it if you go.

[stepintoliquid]

i went through a couple a3's when i was on a turbo setup.

it is a very underrated torquey motor when on boost. however the rods are a definite weakpoint when moving into the mid-300s. low 300hp and a safe tune though you should be good to go no worries.

[sleepy ep3]

i went through a couple a3's when i was on a turbo setup.

it is a very underrated torquey motor when on boost. however the rods are a definite weakpoint when moving into the mid-300s. low 300hp and a safe tune though you should be good to go no worries.
Careful. Any attempt to bring logic into this thread by stating oem a3 parts are sub-par will result in ridicule.

[AKEP]

wait, a3 parts are sub-par though...

[sleepy ep3]

wait, a3 parts are sub-par though...

Shhhhh! They will hear you. The A3 building money wasters that have to prove to the forums and the world that the a3 can handle 300+ hp, forever.

[vividk20]

I'm with the original poster...when I blow up my a3 I'll be doing a motor swap, just can't explain to the wife why I should swap the motor if it's still running fine. Good luck and keep us posted on how the car's running.

[Blah1219]

I'm with the original poster...when I blow up my a3 I'll be doing a motor swap, just can't explain to the wife why I should swap the motor if it's still running fine. Good luck and keep us posted on how the car's running.

Just do what I did take the k20a3 up to redline in 5th gear and wait till you snap a rod -_- too easy

[AKEP]

let us know how much you got away with when you do it.

[gtolio]

I need a new map sensor and the boost by gear solenoid before I up it, but hopefully later this summer. My wife is in nursing school, so we're trying to save as much as we can right now.

The car is still running like a champ though. The other night, I was coming home from a local meet at 1:30 in the morning. A C6 (non Z06) wanted to play on the highway. We did 5+ pulls and it pulled hard on the Vette each and every time, even when they got the jump on me. 60 or 70 to 120.

[ep3k20]

Shoot Tai from Corsport a PM. He was running pretty much exactly what you are asking, had a good tune, and EVENTUALLY (not as fast as other did) blew the a3, but it was around quite a long time that way from what I recall. I'm sure he'll be able to answer most of your questions.

ya and that motor is still on display in the shop too lol love tai

[Dreadknotz1025]

Has anyone been able to update this thread with their respective K20a3 endeavors?

i know its been ages since the thread has been updated, but i would love to imagine there are still ppl out there on boost for yrs :mangel:

How are they holding up?

[monjarassi]

I have a good friend of mine that has a boosted a3 still and motor is still holding up just fine. He doesn't beat on it everyday and hardly drives it but still going strong

[NZGuy88]

I'll let you guys know how i go in 2weeks when i get my ecu back and i take it to get tuned. I live in new zealand so gotta wait for my ecu to get back here from the USA, sooner the better lol, if i make 350whp i will be so happy, its only my daily driver so i wont be taking it to the track or anything, is 12psi safe on the A3?

[Dreadknotz1025]

I have a good friend of mine that has a boosted a3 still and motor is still holding up just fine. He doesn't beat on it everyday and hardly drives it but still going strong

looking forward to hearing similar reports as yours. any idea of the power he is maintaining?

[dcjive]

If memory serves me correctly, from this forum back when I had my 1st ep, back in 06, I'd read that one of the weak links in the a3 was the oil pump, which can't keep up with revs above 6900 rpm. Its a problem unique to the a3, and it doesn't take much imagination to come up with the list of problems that can cause

[Last]

If memory serves me correctly, from this forum back when I had my 1st ep, back in 06, I'd read that one of the weak links in the a3 was the oil pump, which can't keep up with revs above 6900 rpm. Its a problem unique to the a3, and it doesn't take much imagination to come up with the list of problems that can cause

The oil pump is the same as the A2 so I’m pretty sure it can keep up oil pressure at those RPM. Don’t believe me, get part numbers for both model cars and you will see that it is the same.

[Last]

I got a stock k20a3 turbo making about 275HP at 15psi of boost. Issues that arose was stock clutch and stock fuel system limiting the Potential Horsepower that it could make. Changed to stage 4 clutch and now have a return fuel set up with regulator to run E85 with injectors and fuel pump. The HP gains per pound of boost is about 7.6, my set up is rated for about 300-400 horses before I run into turbo problems, but for the build that’s plenty. Raising boost to about 25psi and adding E85 which is automatically a 50HP gain in most cases. The car would make about 400 theoretically. Or use 5psi less and be at 20psi and be about 360HP. Sounds realistic to me given what the car has achieved already, and having cooling properties from running E85 let’s hope the engine can last.