how much boost??

[davjos81]

I'm buying a junk motor here soon, to rip apart and rebuild from scratch. How much boost do you think I would be able to run through a motor w/ forged rods and pistons?

[phoenix64]

Whats you compression ratio? What octane are you going to be running? Intercooler?

[davjos81]

im talking to tiago, im going to run a big front mount intercooler, 8.0:1 compression pistons, forged rods, replace all the bearings, and have the motor bored .10 over. Ill run 93 octane, daily, maybe something higher to race.

[Teufel Hunden]

All just depends on how much money you spend on it, really. You could build a stout little motor to run 30psi if you wanted. For pump gas, i'm thinking the most you'd want is around the 15-18psi range. you could probably go higher with 8.0 c/r, but that's generally the good rule of thumb.

[oil pan 4]

One way to look at it is figure out how much power it will most likely make N/A say you figure it will make 250hp n/a.
Then when you dubble the absolute pressure (run 15psi of boost) you will dubble the power out put.
The turbo size is just as important as the engine build in this case.
How much work were you going to have done?
heads P&P, turbo cam, (custom if you are going to run much over 20psi) and stuff like that will cause your boost pressure to be lower but hp out put to be higher.
If you get P&P heads and intake, valve train, custom cam, forged pistons and rods, the right size turbo, big intercooler, the fuel and fuel system. You could run 20psi but I think you would have to use race gas.
8:1 would be good for 20psi I think.
The 3800II has Al heads, yes 8:1 will be good.
With that much boost you will have to think a little bit harder about cylinder sealing like what cylinder head gasket you will use and if U will copper or SS O-ringing the block.
I have herd that an engine running that much boost can have combustion chanber pressures high as 3,000psi or more. Not much room for error.

[T-Punk]

i would suggest running a higher compression of about 8.5:1 and a lower boost of about 15psi. at that level you will run about 400hp with a propper setup with all forged internals. now if you want to go all out a forged 4.1 stroker kit will be available soon and with that you would want to get the 8:1cr pistons because the stroker adds more compression (with 8:1 it would change it to somewhere between 8.5 and 8.7:1) this would still allow for 15 psi if you upgrade your vavetrain and do some extensive headwork. again though at this level you will probably want to get a custom cam and you will have to do some work with your seals. and as oilpan said (and i cant stress this enough) your turbo choice is as important as you engine build.

[Turbo V6 Camaro]

Originally posted by davjos81:
im talking to tiago, im going to run a big front mount intercooler, 8.0:1 compression pistons, forged rods, replace all the bearings, and have the motor bored .10 over. Ill run 93 octane, daily, maybe something higher to race.

jsut so you know what your getting into, i have about 10-15k in the motor alone, and 21,500 in the hole car, you auto will take a crap,(25,000 or more whe its all siad and done.

OILPAN: the 3.8 DOES NOT HAVE AL heads they are cast IRON
8:1 will be fine that's what intense drag car runs.

you will want to order tiagos kit and upgrade to the t-66 or t-72. that the mistak i made and only time will tell if the turbo will push my 7100 RPM limiter

[Turbo V6 Camaro]

this should help you alot http://www.smokemup.com/auto_math/index.php

[Turbo V6 Camaro]

if you run 8.5:1 c/r at 20 psi
Result:
20.06 : 1 Effective Compr. Ratio :eek:

[Turbo V6 Camaro]

oh yeah dont forget you cam is a big factor in C/R too

[20-psi]

MAN, everybody is calling my name.

Thanks 20-psi

[20-psi]

First you are going to have to decide what you are going to do, race only or daily driver. You can build the engine for either. The Indy 500 speed record was done with a 3.8 stock block and they ran 3 bars (45 psi).

20-psi

[Turbo V6 Camaro]

Originally posted by 20-psi:
First you are going to have to decide what you are going to do, race only or daily driver. You can build the engine for either. The Indy 500 speed record was done with a 3.8 stock block and they ran 3 bars (45 psi).

20-psi

my goal is a 10sec daily

[Tiago]

:eek:

[Turbo V6 Camaro]

Originally posted by 20-psi:
First you are going to have to decide what you are going to do, race only or daily driver. You can build the engine for either. The Indy 500 speed record was done with a 3.8 stock block and they ran 3 bars (45 psi).

20-psi

wait a sec were have you been your membe 55x and only still green