serious internal engine discussion. time to get to business

[!@#$%]

This thread is about all-motor mods (non-turbo build-up)

okay, next week I will be ordering the skunk2 cat back exhaust. I will have injen cai, dc header and skunk2 exh. now that the set will be complete it's time to get a head start on some real motor mods.

Pistons:
Only high compression pistons I have found so far are made by wiseco. They are 11.5:1 cr, but I would feel better off with the rsx-s pistons. (same cr) What is bad about going too high of a compression ratio? I assume the rsx-s (or ctr) pistons would be more reliable/better fit than any aftermarket options....someone expand on that please.

Race engineering makes some k20 pistons as well, but I couldn't find the cr on them. (they might be turbo)
pretty good site here: Race engineering

Connecting Rods:
Crower has connecting rods available as we speak. Supposedly the only aftermarket company that offers k20 rods.... [that I have found]

Crank:
I know that our crank is completely different than that of the k20a2. I doubt that Toda or Crower would make stroker kits for the k20a3 specific. When they do, it will be for the k20a2, but I'm pretty sure it won't matter either way. Only time will tell. Crower will more than likely sell the crank separately eventually. (if they make one)

Cams:
I have alot of hope riding on the Skunk2 cams that are rumored to be in development for the a3 right now. I'll give it another 4-5 months or so for a release. They had better give more valvetrain for the k20 as well. (valve springs and retainers) [This would help greatly with the hondata!]

Also....Skunk2 adveritses a k20 head port job. There is no price listed of course, but the picture looks very nice. (Port and polish on intake and exhaust sides.)

Port and polish:
"Skunk2's ported RSX head is designed and developed for the intake and exhaust sides to maximize laminar airflow at a relatively low price. This is the the true tuner only, and not for any pansy-ass wannabe." - super street pg.162 June 03

I'm assuming that you send in the engine head, they do their thing, then mail it back similar to the process of hondata. I plan on calling them sometime in the future after I buy the catback for more specifics on this....

Hondata/All-motor theory:
People with hondata aren't getting any gains past 6800 making it seem the mod's only asset is for gearing purposes. I'm 99% sure that if we bump up the compression ratio and get some stage one cams and appropriate valve train we could easily see 20 whp gains. The hondata will not shine until the next step is taken. Maybe doug will develop another tune along-side a Forced Induction flash for cams/pistons etc, or maybe this flash will be compatible all-motor where our engines internally are too detuned to put out any more hp/tq figures.

Anyone that wants to discuss and teach me something about engine work I would greatly appreciate the pm. I don't think the vtec in the rsx-s really makes that much of a difference if the k20a3 also has the same compression pistons, cams, ecu etc.

I want roughly 175 whp. This seems easliy attainable through full engine modification. I want to see what this motor is capable of making. Let's see this factory detuned motor unleashed.

-Alex

[chet]

EXCELLENT COMMENTS AND QUESTIONS!!

I have been wondering a lot of the same questions. Although I would sound like a boob/noob if I asked the same things. Anyway, I am only assuming that the K-series engines haven't been in production long enough for many of the companies to have finished aftermarket products yet. Especially the EP. Plus, I would guess that the guys who work on and drive the test models are enjoying themselves and are in no hurry to quit!! I am also assuming that there are SO MANY H and B series engines out there being modded, that the companies direct there production towards those models and customers. I would hope by the end of the year around Christmas, we should have plenty of choices of products to go for. I am excited about finding out, what the k20A3 is actually capable of. If Honda decided to go and design a different engine, they had to have good reason, and plenty of influence from the world of racing as well. A Honda engine is on the poll at Indy BTW.

[JSIR]

I think the RSX-S pistons will be plenty fine, most aftermarkets are forged pistons, no real need for forged pistons unless you are boosting and want to protect from severe detonation. Honda hypereutectic cast pistons are very nice. Forged pistons are lighter though, but they can be noisy on start up and use a bit more oil than honda pistons. Benefits to both sides of the piston debate.

Rods are good if you intend to rev the engine much higher than the stock limiter, I would say over 7500 rpms on a regular basis. In which case a stronger and lighter rod will be good insurance. I would try to find a lighter rod, strength is not as important in NA form as you don't have to worry about bending rods as you do in boosted situations. If you plan on keeping the revs to 7500 rpms or less I think aftermarket rods are not needed, the stock ones and the stock bottom end is plenty strong.

Head work is a good idea, I think there are some gains to be found there. I don't think you need both cams and head work though, one or the other. You can get increased flow with head work or larger cams, you don't necessarily get double the flow with headwork and cams. Head work geared around the stock cams should be plenty for up to 7500 rpms. If you want to make power over 7500 rpms then some large cams would likely be needed. But, the manufacturing process for cams may be tricky as our engines alter cam timing up to 50 degrees, this can be tricky for anyone to develop a real wild cam, unless they deactivate the variable cam timing control such as Toda offers for the RSX-S engine. I would prefer not to do that though.

I wouldnt touch the crank, Honda cranks are bullet proof. If you are putting in rods and pistons you may want to get the whole assembly high speed balanced, maybe add in a lighter flywheel at the same time. That's about all that would be needed.

If I was going to throw some money into the engine , I would increase compression with RSX-S pistons, keep the stock rods and bottom end, and probably go with some head work, and keep the revs to 7500 rpms. A set of mild street cams could be added to the mix if needed at later time if you find you need more top end power, but I think the head work would be plenty good for 7500 rpms. This would be working with basic bolt-on mods and an ecu upgrade for the rev limiter.

just some thoughts.

[fsugatorbait]

What would you consider changing on the bottom end if you were going to add the RSX-S head and ecu which would raise the rev limiter to 8200 rpms? Along with the S pistons I would assume you would also need the valve springs & retainers, but would you also recommend getting the rods as well?
Phil

[Marcivi]

Thanks for the post and question. Been having these seem thoughts rolling around in my head as well. I'd like to keep my EP N/A for as long as I can. I'm sure somewhere down the road I'll be chomping at the bit for more power though. People here at the office tell me that if that happens to buy a V-8 though. Blasphemy!

[JSIR]

Originally posted by fsugatorbait
What would you consider changing on the bottom end if you were going to add the RSX-S head and ecu which would raise the rev limiter to 8200 rpms? Along with the S pistons I would assume you would also need the valve springs & retainers, but would you also recommend getting the rods as well?
Phil

If you could swing the RSX-S rods and bearings and they fit properly with the stock crank that might be a good upgrade for someone that wants to rev the engine a lot. I have no idea what they would cost, you might be able to get a less expensive and lighter rod in the aftermarket though. not sure. Definitely have the assembly high speed balanced though. The RSX-S valvesprings would be plenty for 8200 rpms if using the RSX-s head, I wouldn't swap them for anything in the aftermarket unless you want to go 9000 rpms or more. hth.

[fsugatorbait]

Thanks for you response. Im just interested in swapping the A2 head and ecu for right now, so for that application you think that the S valve springs would be good enough for an 8200 cutoff?

[JSIR]

Originally posted by fsugatorbait
Thanks for you response. Im just interested in swapping the A2 head and ecu for right now, so for that application you think that the S valve springs would be good enough for an 8200 cutoff?

absolutely, the RSX-S guys are taking them to 8700 I believe with Hondata. no probs that way.

[Steve02Si]

It'd be far cheaper, easier, and more reliable to just swap the K20A2 and sell the A3. You'd get just as much power and better gas mileage too. I understand the desire to see what you can get out of what you already have, but in essence the only thing left stock would be the block, so what's the point?

[!@#$%]

the point.....check your sig. We are trying to think different. Nobody is even giving the k20a3 a chance even though its the exact same engine with different guts. [and a few extra roller rockers] I personally am not looking for 200+ whp so I see no need of hassle to try and buy an a2 for 3K then sell my a3 for 2K when I only plan on spending roughly $1000-$1500 on internals.

Remember.....think differently ;)

if i wanted to invest in something for 240+ whp I would have just bought an RSX-s, but I'm just a college student with a hobby. :)

-Alex

[Steve02Si]

The idea of using A2 internals to build up an A3 isn't exactly thinking different. It's been brought up on these forums since the cars came out. If you think you're going to save any money over an A2 swap, I'd love to see that pulled off! Besides, you still won't have a 6speed or higher rev limit (which you'd need to take advantage of the freer flowing head/cams and compression bump). Are you factoring a clutch into your budget? I'd guess the RSX-S clutch is stronger than ours. Who's going to assemble the bottom end? ...

I'd be trying to utilize what the A3 does offer over the A2: lower compression and wider gearing. What's this good for? BOOST! How about having a custom manifold made, pick up a nice T3 or 16G or something, get a stock intercooler off a turbo car, some injectors and a pump, an AFC, ... and see what happens.

[2k2_nbp_egg]

Sorry for the thread jack but...

Holy fuck.

My friend just linked me a thread on CSi w/ a 265~ish WHP 170ft/lb of WTQ K20A2 on 91 octane. It was rebuilt w/ higher compression pistons/rods, new cams, intake manifold...uhh header and head work im assuming and maybe like an vafc or ecu tuning? Idunno, i read it earlier today at school and don't feel like finding it, but thats pretty fucking crazy IMO. 300ish crank HP out of a NA 2L. Thats fucking impressive.

Anyway, back to the A3....


*edit* actually found the original at vtec.net ....

http://www.vtec.net/articles/view-ar...icle_id=101836

[JSIR]

Originally posted by 2k2_nbp_egg
Sorry for the thread jack but...

Holy fuck.

My friend just linked me a thread on CSi w/ a 265~ish WHP 170ft/lb of WTQ K20A2 on 91 octane. It was rebuilt w/ higher compression pistons/rods, new cams, intake manifold...uhh header and head work im assuming and maybe like an vafc or ecu tuning? Idunno, i read it earlier today at school and don't feel like finding it, but thats pretty fucking crazy IMO. 300ish crank HP out of a NA 2L. Thats fucking impressive.

Anyway, back to the A3....


*edit* actually found the original at vtec.net ....

http://www.vtec.net/articles/view-ar...icle_id=101836

that is a $15,000 engine though , you can boost for 20% of the cost and have more power, kinda pointless to spend that kinda money on an all motor setup iMO.

[TomR123]

Simply put if you want around 250 HP coming out of a 2.0 L engine you swap in the type S engine and add any toda racing component you can find. Right there is your simple swap with hours of hobby work installing cams springs retainers and high compression pistons. www.todaracing.com its all there.

[myeverlovinsir]

Hondata/All-motor theory:
People with hondata aren't getting any gains past 6800 making it seem the mod's only asset is for gearing purposes.

Yes there is a slight gain, due to adv. timing. I would word this
that the gains occur during the 0-6800 rpms. I love the livelyness
of Hondata. Stock is just not as agressive. With I/H/E things are just enhanced another 12-20 hp depending on the setup.

I personally am not looking for 200+ whp so I see no need of hassle to try and buy an a2 for 3K

Spend a little, get alot is what you just cannot do for this engine, if 200+ hp is a taste of the ctr, and you persue the type-r influence, the only other feasable option is boost.

absolutely, the RSX-S guys are taking them to 8700 I believe with Hondata. no probs that way.

The RSX-S makes power up there too. We have a head limitation.


If I was going to throw some money into the engine , I would increase compression with RSX-S pistons, keep the stock rods and bottom end, and probably go with some head work, and keep the revs to 7500 rpms. A set of mild street cams could be added to the mix if needed at later time if you find you need more top end power, but I think the head work would be plenty good for 7500 rpms. This would be working with basic bolt-on mods and an ecu upgrade for the rev limiter.



Excellent thoughts guys