Pistons

[jbird]

Hey, I have a question. My buddy who has an a3 is wanting to go fi, but before we install the turbo, we are going to build the engine. I am wondering what are some of your suggestions for pistons? We are going for a 300whp dd with a bullet proof set up. I'm pretty sure I have everything else figured out(turbo, rest of the internals, susp, exhaust, etc) except the piston size. Should I get forged lower compression pistons, or stick with the 9.8:1?

Thanks for the help guys.





HAHA! Just realized that was my first post! I've been on here since July, but I mostly just read....

[BlownSi05]

when i had this wild hair up my ass to build the k20a3 and go turbo i was going to just do 9:1 pistons and new rods. the compression is low enough to be able to handle a good bit with upgraded parts. ARP head studs and a cometic head gasket might be something to invest in as well. if you spend the money to do it right and it is tuned well, you can make 300whp turboed on a stock a3 and it will be reliable. just remember that no matter how you build it, there is always a way to blow it up:mbiggrin:

[Fico]

you will be fine with even 11.5 to 1 pistons you will need less bost to hit 300whp too you just need to get a little more precise with the tune, unless your going for major boost you really dont need 9.0 to 1, 10 to 1 would be sufficent

[talonXracer]

Having a tad more power on hand before boost builds isnt a bad thing, so dont drop the compression too low. Just make sure to have the piston domes ceramic coated.

[jbird]

when i had this wild hair up my ass to build the k20a3 and go turbo i was going to just do 9:1 pistons and new rods. the compression is low enough to be able to handle a good bit with upgraded parts. ARP head studs and a cometic head gasket might be something to invest in as well. if you spend the money to do it right and it is tuned well, you can make 300whp turboed on a stock a3 and it will be reliable. just remember that no matter how you build it, there is always a way to blow it up:mbiggrin:

Yeah, plan on getting arp head studs, cometic 86mm, eagle rods, bc springs, titanium retainers, ss valves, and cam. It won't be all at once, cause hell...I'm not rich! haha! Also, there is a place out in Kansas City that has done some respectable work with Civics, so that's where we will take it to get the kpro tuned.

[Fico]

Yeah, plan on getting arp head studs, cometic 86mm, eagle rods, bc springs, titanium retainers, ss valves, and cam. It won't be all at once, cause hell...I'm not rich! haha! Also, there is a place out in Kansas City that has done some respectable work with Civics, so that's where we will take it to get the kpro tuned.

i have heard some bad things about boost and eagle rods but nothing 1st hand, im using blueprint h beams

[jbird]

Thanks for the tip on the rods. I was going to get the eagle esp h's, but if the blueprints really are better, then i'll go with those.
So, you guys think 10:1 pistons will work fine, or would 11:1 be better? Like I said, it's primarily a daily driver, but I want to be able to kill some v8's on the way to work!

[Deadphishy]

Thanks for the tip on the rods. I was going to get the eagle esp h's, but if the blueprints really are better, then i'll go with those.
So, you guys think 10:1 pistons will work fine, or would 11:1 be better? Like I said, it's primarily a daily driver, but I want to be able to kill some v8's on the way to work!

9/1 or 10/1

Your asking for a headach if you want a 11/1 DD turbo set-up

[Lucid Moments]

For 300 whp on a turbo I would actually not lower the boost at all. Maybe even go up. Not sure if I would go all the way to 11:1 although that is entirely feasible, but 10:1 or 10.5:1 for sure. Just depends on what is available.

You can hit 300 whp on the stock rods and pistons. Exactly how reliable that would be is up to questions though

[Fico]

9/1 or 10/1

Your asking for a headach if you want a 11/1 DD turbo set-up

why is that because its what you heard? i have known a few people that dd 11 to 1 boosted people always think oh im boosting i need some 4 to 1 compression! not the case, you need to figure out what your goals are, what about the future will you want more power( alwyas a yes lol), what do you want to accomplish out of your build, and so on

[talonXracer]

Back in the days of iron head V8's and pressurized carburetors it was common practice to drop the compression down when boosting. But in this day of advanced engine control and design, much higher static cr's can be accommodated.

[Deadphishy]

why is that because its what you heard? i have known a few people that dd 11 to 1 boosted people always think oh im boosting i need some 4 to 1 compression! not the case, you need to figure out what your goals are, what about the future will you want more power( alwyas a yes lol), what do you want to accomplish out of your build, and so on

the reason i say this is one day he is going to be running it a little hard, a little longer then you should for a DD, not to mention it will be a 90deg augest day. And that motor will get so hot it will ignite that poor 91octain fuel, and his already smoking hot rings or rods will break.

[talonXracer]

There are a fair amount of turbo charged typeS's out there. But of course a little caution is always advised.