k20a3 upgrade path for DD

[rsnickell]

Yes and yes. BUT a k24a1 can be had for FAR less than either of its a2 brethren...

Yeah I see your point. I found a few k24a1's for under $800 locally thanks to car-part.com. The best I can find of the k20a2/k24a2 engines is around $1,600.

In an effort to keep this on topic for this SuperCharger forum section, would any boltons I get for the k20a3 still have correct fitment on a k24a1 should I decide abandon the JRSC route and instead go swap? That would give me some lead time to make my final decision.

Using the existing ECU on the k24a1 is very attractive alternative to ponying up the kpro + jrsc all at once.

[Ba82Ep3]

Think of the k24a1 as the big brother of the k20a3. Same 2 lobe cam setup, same engine harness connections, same accessories (water pump crank pulley etc) and the intake and exhaust manifolds are interchangeable. The JRSC manifold is designed for this type of head, and actually uses an adapter plate for any of the k series heads that have the water port as part of the intake manifold (where the upper rad hose attaches to the engine, k24a2/k20z3).

Your only real concern during bolt on purchase would be a race header. Because the k24a1 is essentially a stroked and bored k20a3, the block deck height is 19mm taller. This raises the head the same amount. If you bought a race header while you still have a k20, and you had intent to run a k24, you might wanna invest in a k24 header so you can have the chassis clearance... and not have to buy a header twice.

I have worked on a few k24a1's with graduating setups like this... a friend even running the k20a3 ECU with 310's and full I/RH/E didnt lean out his setup. As a matter of fact, he was real close to stoich and the setup ran really well. Adding KPro and some street tuning only found him maybe 10whp and 4wtq more. If i remember correctly... he dyno'd 190whp 180wtq.

Odds are you could safely use the JRSC Street Kit w/Power Card with the stock k20a3 ECU/310cc injectors on a simple bolt on k24a1. I know the power card runs rich, and even though the intake header and exhaust (I/H/E) would lean out the setup... you would likely be safe. Worse case you just leave your catalytic converter on to add some exhaust restriction to help richen it back up some.

That would likely put you in the 220whp 195wtq region... safely... and on the cheap. Buy KPro later on, and open up a world of new options for yourself. If i knew what i know now, and had to do it again... thats the route i would take.

[Blah1219]

Think of the k24a1 as the big brother of the k20a3. Same 2 lobe cam setup, same engine harness connections, same accessories (water pump crank pulley etc) and the intake and exhaust manifolds are interchangeable. The JRSC manifold is designed for this type of head, and actually uses an adapter plate for any of the k series heads that have the water port as part of the intake manifold (where the upper rad hose attaches to the engine, k24a2/k20z3).

Your only real concern during bolt on purchase would be a race header. Because the k24a1 is essentially a stroked and bored k20a3, the block deck height is 19mm taller. This raises the head the same amount. If you bought a race header while you still have a k20, and you had intent to run a k24, you might wanna invest in a k24 header so you can have the chassis clearance... and not have to buy a header twice.

I have worked on a few k24a1's with graduating setups like this... a friend even running the k20a3 ECU with 310's and full I/RH/E didnt lean out his setup. As a matter of fact, he was real close to stoich and the setup ran really well. Adding KPro and some street tuning only found him maybe 10whp and 4wtq more. If i remember correctly... he dyno'd 190whp 180wtq.

Odds are you could safely use the JRSC Street Kit w/Power Card with the stock k20a3 ECU/310cc injectors on a simple bolt on k24a1. I know the power card runs rich, and even though the intake header and exhaust (I/H/E) would lean out the setup... you would likely be safe. Worse case you just leave your catalytic converter on to add some exhaust restriction to help richen it back up some.

That would likely put you in the 220whp 195wtq region... safely... and on the cheap. Buy KPro later on, and open up a world of new options for yourself. If i knew what i know now, and had to do it again... thats the route i would take.

Great article. I just have to add that the k24a1 head is the best flowing head from the factory. You also have the option of doing vtec killer by using the k20a2 cams and k20a3 exhaust rockers, and you'll put out a strong 210.

[rsnickell]

There is a lot of great information here. I have a tough decision on how to do my build.

Your description of going with a k24a1 swap using the k20a3 ecu with 310 injectors eventually hitting 190hp sounds interesting, but required kpro just to get there.

I think I may go the route of getting the i/h/e for the k20a3. Then followup with a kpro. At that point I can decide to go jrsc or k24a1 swap.

Thanks again for all the great info and feedback.

[junevtec]

i think k20a3 jrsc would be fine im gonna go this route whenever i find a cheap jrsc unit

[willy_akino]

LoL...Willy, I don't think you'll go Evo or STI anytime soon..I think the next set up you'll go for after your A3 JRSC will either be a Vtec Killer or K24a1 or K24A2 with that JRSC...hehehe.

i've driven a k20a2/k24 with and without the jrsc and honestly its a load of fun but its not for me. I'm done modding my engine the next thing i wanna do is wheels/coilovers/brakes and jdm front and I know my next car is a s2000(i know its played out) but I've always wanted one.

[gtecd20]

You know I was always thinking what to do as far as either swap or sc and I found a great unit with a power card and boy let me tell u It was a days work installing it and I'm so happy it's not the fastest thing but I can beat g35 newer si and keep up with cars that normally are out of my league I am running a power card saving up to get the kpro but you won't be disappointed any way u go
Either way I recommend upgrading your clutch to Handel the extra torque
Good luck with your build

[EP3Lov3]

Long time lurker/reader.. first time poster.

So I have a EP3 with a K20a3 which after much research am disappointed that it is the econo engine. Now I'm looking to make this DD sort of a project car over the next year or so. It has 70k miles on it now. What I've been trying to establish is what to do with the engine.

I could swap it with another engine like the K20z3 or maybe a k24a2 or k20a2. That's a bit of work for my limited experience and would be costly. Yes I know that you have to pay to play.

I could also go the route of FI with either a JRSC or a Turbo kit.

Next I bet you guys would like to know my target performance. I'd like to get the K20a3 up to the 200hp range. So it's not anything too crazy, just more of a powerband than what it has stock for the DD I have.

After more reading, it sounds like installing a turbo is a bit more involved than installing a JRSC. And either one would get me close to the target of 200hp with I/H/E boltons. I'm leaning more toward the JRSC street kit at this point.

I'm looking for some guidance here as to the next step for this stock k20a3.

Do I get all the boltons first and then go after a JRSC? Can I install a JRSC without the boltons and do the boltons afterwards to get further gains from the JRSC?

What do you think?

If you feel that the JRSC is not the best to reach my target, let me know and include maybe a guess for cost in the route you suggest.

Thanks EP hatchers and be easy on me. It's my first post.

I'm in the same boat as you =)

[Nickle n Dimin]

you'll still be disappointed with the k20a3 and will become more power hungry. Do it right the first time by swapping and that way your money will be worth it. There should be some ephatch members in ohio that can help you swap the motor.

if i could go back i would def do the swap gives you about the same power and more room for improvement later on down the line

[maksym]

Back from the dead....
Would the K20A3 ECU work fine with K24A1 and 310 injectors if the K20A3 ECU is reflashed? Pros? Cons?

[tlikethedrink]

Interesting set up ^^^

[klik]

I used to have jrsc street on my k20a3 and it was cool. Sold the jrsc and bought a kpro for 600 used. And i found a 2007 k24a2 with 30k miles online for 1600 shipped. And a rsx s 6 speed tranny for 500. Im not swap yet since im too busy to do the work. But you can find good deals out there just keep looking around.

[wcmbrk]

if you don't want to give up on ur a3...u can vtec kill your a3...I did it and yea some people don't like it...but I've driven it for 30k miles now and have had zero issues with reliability...how's ur smog over there? If not as bad as cali you can do it...i'm at 191 with a shorty header...race header should put me over 200...and I sourced all the parts online through forum...probably less than 1000...just wanted to be different is all...i'll probably get flamed here for saying I <3 vtec killer...but it's worked well for me...so that's my $0.02.

[maksym]

Back from the dead....
Would the K20A3 ECU work fine with K24A1 and 310 injectors if the K20A3 ECU is reflashed? Pros? Cons?

Anybody on this one?

[Ba82Ep3]

Reflashed how?