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Discussion Starter · #1 ·
i want to swap a rsx type-s block on my 2003 si, is it worth doing it? does anybody knows if i need to change the harness from the rsx too? or they ecu will work on the si harness. any help apriciated.
 

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it's worth doing. K20A2 is an excellent platform for tuning. i think all you need is the complete K20A2, 6spd tranny and the RSX-S ECU. the Si wiring harness will work. i know there's a complete swap 'how to' somewhere. i'll dig it up.

All the European market CTRs are powered by the K20A2.
 

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Are you talking about just the block or the head too? I wouldnt waste my time with just the block as you wont see any real gains out of it. You could swap the a2 head on your a3 block but youll need an oil cooler as the a3 head doesnt have oil squirters. You dont need the type-s tranny either you can use your 5 speed if you dont want to spend the extra cash. If you just swap the block then youll use the ecu out of your ep3 but if you use the head too youll need the type-s ecu. Any other questions ill be happy to answer.

*EDIT* I know a guy who can get you a new TSX k24a2 engine with about 5 miles on it for 2500 bucks shipped. 200hp 180tq, not too shabby. Its not much harder to drop one of those in the si other than just swapping your k20a3 throttle body and intake manifold onto the k24a2, let me know if you want one.
 

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Discussion Starter · #5 ·
my bad

i am really sorry, about the block, i ment that i wanted to swap the head. i am really sorry. but thanx for the info anyways. so to swap the rsx type-s head, i will need the self head, the ecu and what else to make it work.
 

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I am not positive about passing smog, I dont have to worry about that where I live so ive never really looked into it.
To make the head work basicaly you just need the head and ecu. The k20a2 block has oil squirters for the pistons while the a3 block thats in your si doesnt. For that reason you should at least install an oil cooler if you plan on reving past 7k rpms. Your other two options would be to get forged pistons which can withstand more heat or to install oil squirters which would be a pain in the ass but the spots are already marked on the a3 head where you would have to drill. I believe that is all you will need, everything else should bolt right up no problem. If you do go with the head swap while you have the engine apart it would be a great time to install the hondata intake manifold gasket as that will help cool things down a little bit as well. Its like 65 bucks from www.showstoppersusa.com
A lot of people say that they wished they had just dropped in the whole k20a2 engine instead of just doing the head swap. Personally I think it all depends on how much your getting the head for as to if its worth just swapping the head in or dropping the whole motor in there. If you have any specific questions just let me know ill be more than happy to share any bit of information I have. Good luck man.
 

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jreese said:
i wouldn't do it....i'd just go find a used rsx-s
yep, why have a 03 si and put a k20 in there for? youll just spend more money on a car with about the same weight, and same motor as the rsx-s.
for me ill just get the rsx-s cuz it looks nicer and it doesnt have that :g shifter
 

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of course it's not legal, in cali, nothings legal nomore :mad
 

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WhiteTegRacer said:
yep, why have a 03 si and put a k20 in there for? youll just spend more money on a car with about the same weight, and same motor as the rsx-s.
for me ill just get the rsx-s cuz it looks nicer and it doesnt have that :g shifter
First of all the si already has a k20 in it. Its a k20a3.
He wont spend more money, he can get a head swap for about 800 bucks with ecu, installs it himself and thats 800 bucks for 180-190whp. Which if you think about the price most people are getting si's for new about $16,000, that would bring it up to about 16,800...thats cheaper than an rsx-s.
The rsx looking nicer is an opinion, which should have no bearing on someone wanting to do something to THEIR car, if you wanted to swap a motor in your car and someone said not to do it because they thought your car didnt look good, its kind of pointless.
And the shifter is the best and easiest to get to shifter that I have ever used. Go hit up an autox course in an si, youll change your mind about it in a heartbeat.
 

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sivic02 said:
thats 800 bucks for 180-190whp.
just to clarify.... you won't get 180-190whp from a A2/A3 head swap. crank hp yes, but definitely not whp...


on another note: what's gay about the shifter? i guarantee you that in 2-3 more years you'll see dozens of cars move the shifter to this position. not only is it a great location for racing, like sivic02 pointed out, but it frees up all kinds of space in the center console area...
 

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WhiteTegRacer said:
yep, why have a 03 si and put a k20 in there for? youll just spend more money on a car with about the same weight, and same motor as the rsx-s.
for me ill just get the rsx-s cuz it looks nicer and it doesnt have that :g shifter
well, if he's like me and he likes the si because everybody and there little sister owns an rsx then maybe he wants to keep his si and do a swap on it. my ep3 weighs less than the dc5, handles as good possibly better, and the shifter feels much better. you obviously havent driven one or you wouldnt be calling the shifter gay. it's so much easier driving with it seeing as it's right next to the steering wheel. go do some research, and before you call me a newbie, i've probably been doing this longer than you have, thanks.

the swap is definitely worth it, i'm working on one for my car right now.
 

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jdmd said:
well, if he's like me and he likes the si because everybody and there little sister owns an rsx then maybe he wants to keep his si and do a swap on it. my ep3 weighs less than the dc5, handles as good possibly better, and the shifter feels much better. you obviously havent driven one or you wouldnt be calling the shifter gay. it's so much easier driving with it seeing as it's right next to the steering wheel. go do some research, and before you call me a newbie, i've probably been doing this longer than you have, thanks.

the swap is definitely worth it, i'm working on one for my car right now.
its all a matter of OPINION.....i've driven one and i dont like the shifter..
 

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isnbrg9 said:
just to clarify.... you won't get 180-190whp from a A2/A3 head swap. crank hp yes, but definitely not whp...
I had just read somewhere before that that is the kind of gains to expect so I did a little searching and with just the a2 swap+ecu and minor bolt ons I/H/E someone on average hit 173 his best run was 177. Heres a link if anyone wants to check it out.
http://www.ephatch.com/forum/showthread.php?t=36631

Come on I was close lol.

*EDIT* Something else to note I forgot about this until I read it on the other site. If you have the 5 speed and an a2 swap, youll fall out of vtec when your redlining it. The only way to fix it without sacrificing power is to swap out the 6 speed tranny, but its as simple as unbolting the old, and bolting in the new one.
 

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redline_rpm said:
lets say i put a tsx head on my si, will it pass smog? what about my states highway patrol, i will need to be going to the highway patrol, will they say anything?
go to ephatch.com to find out what you need......there have been a few that have put tsx engines in our car, but its a little more troublesome. best bet is the a2 head swap with k-pro..you should be good to 8krpm
 

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a2 head swap is nice, is pretty much a garanteed bolton 30-40hp at the wheels. The 5spd really only sucks on the 1-2 upshift, all the rest are fine. The biggest issues you will run into are that you won't be able to hit the full potential of the head b/c you can't safely rev the bottom end past 8000rpm on a daily basis. To make big power with the k20a2 head, you need to rev past 8000rpm with a set of cams.

Also, I strongly reccomend hondata k-pro.

I think eventually you'll want to upgrade the bottom end. The castings for the a2 & a3 blocks are identical, but the crank, rods, oil pump, etc are different. Really what you'd need are an a2 crank, a2 rods, a2 pistons, a2 oil pump, and then you are set to go. The only other difference is in the oil squirters, water pump & oil cooler (a2 has a separate outlet for the oil cooler). But on a street car, you don't really need the oil cooler unless you like to run really thin oils, nor will the oil squirters make a huge difference in piston temps.

the a2 head swap is a good start, but it will def. leave you wanting more.
 

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Just got the 2005 Si myself. I love the shifter being its in a very symetrical spot with one hand on the wheel and one on the shifter. I agree its a matter of opinion so why would shifter placement matter on swapping heads? Sounds like somone should really swap their head. Hehe.

I love this discussion about the heads swapping, I believe my engine is a K20A3, I know I will not do turbo until its about 3-4 years old, so knowing that what can I do now that would give me some hp gains? I here there arent cams for this engine, is this true? What about increasing rpms? I want a new exhaust but NOT loud, just deep sounding but with best gains. Same with Intake, can you name some brands and where to get them? Throttle bodies?

Ill stop there for now.

thnx
 

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Your engine is a k20a3. Crower should (hopefully) have cams out in the next couple months but if you are planning on going turbo down the road then you wont want to get these cams. As far as increasing rpms check out www.hondata.com and if your interested let me know and I can get you a good deal.
I have the magnaflow exhaust on my si, its pretty deep and by itself its not loud at all. It has shown to give decent gains throughout the rpm range. As far as intakes are concerned most people will tell you that it doesnt matter what intake you get as its only a difference in a couple of hp but the one that has shown the best gains on a dyno (and not the companies dyno) is the injen race division CAI. Although given the choice I personally would go with the Comptech Icebox. If you arent planning on doing any true hardcore mods then I wouldnt worry about a throttle body. Although doing a nice individual throttle body setup is always nice if you have the dough. A couple good sites that have good prices, fast shipping, and great customer service are www.robearracing.com and www.showstoppersusa.com

For future reference if you have a question(s) like this its best to start a new thread instead of taking over an older thread.
 
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