turbo projects begin

[kzoosho]

this commin week im going to be gathering everthing else i need to boost both my dd and my play car both 92's but my dd will remain a 3.0 but my other will get a 3.2 or 3.3 depending on money at the time. i have got most questions answered on here but now i have to ask any tech heads if its true will me building a boosted 3.3 without low compresion net me more low end torque and if so how much. i do know with higher compresion i have run less boost but i would gain low end torque please let me know if this is true thanks in advance

 

[B7 Quattro Man]

I am pretty sure that if you want to go more than 9psi, they recommend to use low compression pistons. If U use new regular compression 3.3 pistons you will be limited to this same psi.

If you plan on using a turbo, you wont have a lack of low end tq. Search the forum and everyone will say that it pays to do it right the first time, which means go low compression pistons. It will allow you to use more boost, with more reliability.

I am in the same boat as you, I have all the gaskets and bearings, and wanted to start building my FI engine using stock pistons, but realized that going the cheap way out when my block is completely stripped is a bad Idea. Just postponed my plans for a while until I can afford to bore out the block and buy 3.3 low comp pistons.

 

[TYSHO]

I am pretty sure that if you want to go more than 9psi, they recommend to use low compression pistons. If U use new regular compression 3.3 pistons you will be limited to this same psi.

You won't be limited to the 9psi without low compression pistons, you'll just have to use higher octane and the best intercooler/aftercooler you can find.

 

[kzoosho]

well someone answered me but u are somewhat right but also wrong building a 3.3 is not cheap either way i just wanted to ask someome here if what the guy that has my eagle talon is true. with the dsm what we call them we use the n/a motor and boost it that elimantates crank walk for 1 and they say with the higher compresion(10.0 to 1 versus 8.5 to 1) they say u can run less boost get the same power but gain power in the low end thats all i was wondering by no means was i or am i trying to be cheap just trying to comfirm thats all

 

[SHOspazz92]

You'll want to talk to " BondoSHO" About a 3.3 .

-Sam

 

[kzoosho]

why would i talk to him about a 3.3

 

[NeedAPartsCar]

He has one.

 

[Toolman]

they say u can run less boost get the same power but gain power in the low end thats all i was wondering

Down and dirty answer is yes. The more HP your engine has NA (generally speaking), the more it will make with a given amount of air. So, a 200whp NA SHO will generally make more power with a certain amount of boost than a FI SHO that started out as a 180whp NA car (keep in mind that boost is simply a measure of restriction not neccessarily a measure of airflow, eg; a head/cam SHO will flow more air at a given rpm, and given boost pressure, than a stock head/cam SHO). Make sense? So yes, more compression (to a point) will make more power, assuming all other variables are the same.

As far as making more TQ at low rpms, it is a moot point. For one, it depends largely on compressor selection, exhaust design, the modifications done to the NA engine, etc, etc. Besides, with a properly matched compressor, you will have all the TQ you need, whatever CR you choose. In the end, I would never recommend someone looking to make MORE FI power to do so via running a higher CR. If ultimate power (HP and TQ) is your goal, forged pistons are a good idea. FWIW, Josh @ SHOnut makes incredible amounts of power with his stock block (including bore and pistons last I heard) SHO. Keep in mind he has an air/water aftercooler and is a Tweecer genuis. And he has still blown a few pistons up from what I have heard. For the trouble of replacing broken pistons, and the possiblity of further damage, I suggest spend a few hundred dollars on some forged slugs with a slighty lower CR. You will then noy be limited on the amount of boost you run (to a point, assuming you have the other mods you will need).

 

[thecrew2999]

with a 3.3 it would make sense to gain some more low end over 3.2
a simple compairision is the 3.0 to the 3.2 you gain more low end with the bigger pistons which is a rule of thumb more cubes more tq.
i dont think it would be a big gain but i would say in a boosted car it would a big difference