Thread: Pulleys = what boost numbers?

I AM UNSURE AND IM SURE ALOT OTHERS GUYS N GALS WHAT ARE THE RELATIONSHIPS FROM BOOST MADE TO THE SIZE OF THE PULLEY? THANKS

??

Like boost levels compared to pulley size? Because there is no rule of thumb...if your car flows good it makes less boost. Or, could make 15psi on a 3.4" if you don't flow well enough.

basically...

3.8" = 5-7psi
3.5" = 8-9psi
3.4" = 10-ish psi
3.2" = 11psi + and so on...for the most part.

^ thats pretty much it. I see 10.2 right before I shift with my 3.4
with my 3.5 I saw about 9.4 max.

heh...I saw 15psi with my 3.2"...and it didn't knock at all...and that setup ran like a raped ape. I loved it.

Think what your new set up will be .......

i see 12 on my 3.4 with headers

Originally Posted by BoostJunki3

i see 12 on my 3.4 with headers

Then it isn't flowing good enough.

I saw 11 with a 3.25" with headers.

there is no set amount. it depends on how well your motor flows.

/thread

i only see 9.8 psi on a 3.4 with a huge cam and high compression

weather effects it also does it not??

yup cold air is denser and then you make more boost.

Originally Posted by Zach3800

i only see 9.8 psi on a 3.4 with a huge cam and high compression

And I saw a max of 9.0 with my stock 3.8 setup....obviously it is all about flow....headers, porting, exhaust mods, etc.

flow has everything to do with boost levels so does weather

Originally Posted by Zach3800

flow has everything to do with boost levels so does weather

I agree! on a3.4 pulley im seeing 7psi with my port headers & catless exhaust.

Originally Posted by bluegtp91

Then it isn't flowing good enough.

I saw 11 with a 3.25" with headers.

im seeing 12 because im boost stacking i believe tho because i get a constant 9-10 then right before the shift it shoots to 12 real quick...

How are you stacking with headers?

You need a ported blower...and a better tune prolly...

in the video he posted, it dident jump up till right at redline. maybe the supercharger just turning harder, idk

Its a roots blower, It's pushed air. Your not going to have the same psi from car to car, pulley to pulley.