need help with compression choices

[rusty#1]

hey guys i was wondering if some one can help me with what compression i should run i am doing a built a3 motor with the skunk2 2 stage 2 cams and basic bolt ons, and in maybe like 6 months i plan on doing a jrsc i was thinking the wiseco 11.1 but what about 11.5 because i was thinking since the a3 head is not very aggressive i would need to make up for some power ??




Thanks

[SiR R8TD]

If your going to spend all that $$$ go w/ a K24A2. K20A2, Z3, Z1... anything i-VTEC. The K24A1 is a good alternative also. The A3 is great but, it's tuning & reliability potential is limited compared to other K-series motors...IMO.

[rusty#1]

yea i kno where ur coming from but i really want to stick with the a3 so what compression would u say with those mods and future mods and im gonna be using the type s jrsc with some slight modifications:mbiggrin: my goal is really only 315 wheel or more but i am looking for more of a fast reliable car hence built jrsc

[rusty#1]

i am confused about what compression to run because of the less aggressive head so i was thinking 11.5 to make up for that but im not sure also becuase the stage 2 cams that skunk2 says is the best for supercharger applications im also want to use the type s jrsc yes i kno u need to modify some things but i dont plan on selling the ep for a long time some help plz

[civsirmt]

idk man i think ur goal of 300whp on an jrsc is a little high. even built with boost cams mabe 260ish giv or take, but that is still a but load of power and great low end and reliable too(depending on the build)

[rusty#1]

260ish doesn't sound logical because there are ppl here with jrsc a3s with very good bolt ons and tunes pushing 240-250 and this is a guy with bc cams jrsc pushing i think 260-270 or something like that

[civsirmt]

260ish doesn't sound logical because there are ppl here with jrsc a3s with very good bolt ons and tunes pushing 240-250 and this is a guy with bc cams jrsc pushing i think 260-270 or something like that

a built a3 block will not get u 35 to 40hp

[kprocivic]

yeah your not getting 300 with the a3. i dont know if changing the compression on the a3 is worth it. its already low compression for a reason and with sk2 stg2 and jrsc and higher compression sounds fatal. if you want 300 you need turbo. or supercharged swap with boltons and a fresh tune.

[v1c10us]

at least not built the way he's saying..
Sure you could bore hone sleeve port polish get a whole new ferrea valve train cam it and get a stroker kit and you might be lookin at some good numbers with a good tune.
But you could also just resleeve it and change the valve train, keep the cams and boost and get a good tune and make just as much.
or you could swap a k24a1 and boost.
you are taking the hardest route for the least benefit.
not to mention who builds a motor High compression for F/I. and even more, who builds a motor to just supercharge it..

[blackhatchsi]

you could swap a k24a1 and boost.
you are taking the hardest route for the least benefit.

Also most expensive with the most downtime. K24 swap and save money and time. Then buy more parts with the money you save.

[rusty#1]

yea i get what your saying but jpax i think was doing 11.1 with his k24 jrsc isnt that high compression. But rsxs do about 280 with a stock head and some bolt ons and good tune im putting in slightly more aggressive cams with a p&p and around the same compression

[rusty#1]

i have also explained my setup to skunk2 they said that 300 should be very achievable; btw i thank u guys for your insight

[civsirmt]

yea i get what your saying but jpax i think was doing 11.1 with his k24 jrsc isnt that high compression. But rsxs do about 280 with a stock head and some bolt ons and good tune im putting in slightly more aggressive cams with a p&p and around the same compression

they are a2s bro a different ball game

[SyckSiR]

i have also explained my setup to skunk2 they said that 300 should be very achievable; btw i thank u guys for your insight

I think u need to listen to the ppl here dude....building an a3 is like getting the best VCR you can get.....where you could get a DVD Player (K20a2) or a Blue Ray (K24a2 or frank). You can do what u want, but that doesnt make it a good idea.....

[rusty#1]

lol nice comparison so theres nothing i can do i really want to stick with the a3 and supercharge it. an my car is gonna go into the shop soon all i am missing is pistons any suggestions guys.. should i just go for it an try?



thanks

[SyckSiR]

lol nice comparison so theres nothing i can do i really want to stick with the a3 and supercharge it. an my car is gonna go into the shop soon all i am missing is pistons any suggestions guys.. should i just go for it an try?



thanks

then stick with the a3 and supercharge it.....but dont expect 300hp at the wheels. And why would u need 300hp at the wheels anyways??? Are you tracking the car? Or just street racing??? There is NO point messing with the a3's internals, like everyone said either swap a k24a1 head on it, or swap out the whole motor. Either that or forget about the charger and put a turbo on and have it tuned and u can hit 300.....

[blackhatchsi]

if you are just dead set on sticking with the a3, then I would stay around the stock compression on the pistons since you're gonna boost it.

[rusty#1]

i guess its just a pride thing lol so im just gonna go with supercharging my a3 with my setup but can u guys tell me what compression would u go with

[rusty#1]

i guy i asked along time ago said go with 11. ?

[blackhatchsi]

The only reason that I would do anything to the internals on the a3 is to improve strength. But the stock compression would be better for boosting than going with a higher compression. I just think that with your hp goals, if you go with a higher compression, it could be disasterous.

[rusty#1]

are u saying it could be dangerous cuz of the cams or compression cuz the rsxs have 11. compression ??

[clujalolo]

if i were to chose compression i would say around the 9-10 area. dont go 11, to high for boost. but thats my imo. but for the safest go for a stronger piston then stock but same compression or near stock compression

[rusty#1]

thanks buddy soo does everyone agree with 10.5 ? but im curious are u guys saying that the type s ppl maxing out there superchargers i think its at 10 or 11 psi with 11 compression isnt a good idea or are u saying that it isnt a good idea for me to run that compression with the cams??

[blackhatchsi]

thanks buddy soo does everyone agree with 10.5 ? but im curious are u guys saying that the type s ppl maxing out there superchargers i think its at 10 or 11 psi with 11 compression isnt a good idea or are u saying that it isnt a good idea for me to run that compression with the cams??

The rsx ppl are running a k20a2 unless they are running a base rsx. But with those numbers, I'm pretty sure that they are driving a type-s. It's totally different than the a3.

[rusty#1]

yea i understand but im going to have forged internals im basically gonna have a built motor tho?? so can i run 11 then??

[nightrider2002]

If you are going to build the A3 block you might as well put in a K20A2 crank since it is better balanced. That way if you get sick of the A3 head you could always slap on a 3 lobe vtec head type s for example, and you would have a nice supercharged setup without needing cams.

For the compression don't go higher than 11. You could always get 10.5 pistons and then get them coated to slightly up the compression.

[Soprano21]

lol nice comparison so theres nothing i can do i really want to stick with the a3 and supercharge it. an my car is gonna go into the shop soon all i am missing is pistons any suggestions guys.. should i just go for it an try?



thanks

if you wanna keep the A3 head why not go with Skunk2 stg1 cams, RC header, exhaust, intake, boost(SC)

[talonXracer]

Building the A3 is a Total waste, unless you are going turbo.

You should go with a typeS crank, the A3 has smaller rod journals.

You can run 11:1 pistons in the A3, but without a A2 head you will never see the WHP level you are looking for with a Sc(unless you use Churchs dyno).

The aftermarket cams for the A3 are relatively small, barely having the lift and duration that the big cam lobe on a stock A2 cam has.

For what you are gonna spend on the A3 for machine work, you would be much further ahead with a simple K24A2 swap and Sc that.

[v1c10us]

keep the stock compression with stronger rods and pistons and a re sleeve and tell the supercharger to screw itself.
Go turbocharger and run 12 psi.

[Soprano21]

keep the stock compression with stronger rods and pistons and a re sleeve and tell the supercharger to screw itself.
Go turbocharger and run 12 psi.

true but what if doesnt know to much about turbo's a SC would be a little bit eaiser to maintain

[v1c10us]

then he doesnt need to be rebuilding his motor or turbo or SCing his car.
go get a corolla.. You wont have to worry about maintenance so much, but they're boring as shit

[4angrybadgers]

then he doesnt need to be rebuilding his motor or turbo or SCing his car.
go get a corolla.. You wont have to worry about maintenance so much, but they're boring as shit

:mrolleyes: Goddamn you are dumb. So you're saying that if the guy doesn't know much about turbo maintenance he shouldn't touch cars period? There are plenty of people who don't want to fuck around with turbos, but have good cars regardless.

[Soprano21]

:mrolleyes: Goddamn you are dumb. So you're saying that if the guy doesn't know much about turbo maintenance he shouldn't touch cars period? There are plenty of people who don't want to fuck around with turbos, but have good cars regardless.

OUCH!!:mtongue:

either way if he was to go N/A or SC it would still be eaiser to maintain then a turbo

[v1c10us]

okay maybe my statement wasn't so hot
basically im just annoyed as shit because this is possibly the longest string of dumb questions, typo ridden sentences and unwillingness to accept facts that i have ever encountered.
The way the guy is talking is just really; "I just watched the fast and the furious for the first time and now im gonna go and rebuild this motor and supercharge it and get a billion horsepower, i dont care if its not possible because im getting a Port and polish so that'll make up for the a3 head right?"
if you cant understand why your car wont make those numbers, you shouldnt try to make them.
Sure, the turbo is a bit more maintenance, but honestly if you get a modest tune and a good install on the kit you're not gonna be doing all that maintenance..
maybe my view on alot of maintenance and yours are different, keep in mind you're like 10 years older than me and I have alot more time and energy to do stuff than you.

[4angrybadgers]

First off, I apologize for being an ass.

I see your point in your explanation, and I have to agree. But at this point I don't think telling him he's an idiot will help much... either he'll listen to the advice from you and the others, or he's just gonna do what he wants and learn the hard way. (probably option B)


keep in mind you're like 10 years older than me and I have alot more time and energy to do stuff than you.
HEY NOW. I'm only 24. :mbiggrin: