Thread: Question about how much boost I'm running?

i was at 10 psi on a 3.4 in the heat. 12 in sub freezing temps.

i was at 8 when stock. the headers and rockers dropped it to 5.3 psi

your seems low.

Originally Posted by Tonkin2000GT

I just installed dual aeroforce gauges and an autometer boost guage I was wondering does 8lbs of boost on a 3.4 pulley sound about right?

How about listing all your mods?

I'm damn near in a pineapple under the sea the elevation is so low here and with a 3.4 on my 05' I was hitting nearly 15psi until I changed it to a 3.8" pulley now it will hit 10 on a downshift and at night but when it's 99+ out 8psi is tops with a stock car.

Jeff

3.4 on stock manifolds is super restrictive. thats why 15 psi. with headers its closer to 10.

Yeah I know, altitude makes a big difference too. The OP never mentioned mods so if he's stock maybe he has a ford check valve in there...


Jeff

I know, I bought the car like that and then installed a 3.8", then installed another supercharger with a 3.8" while I was trying to figure out what was wrong with my car. No worries its stock again.

Jeff

was the car n/a to start? did you wire up the map sensor got a l67? or wire up the bbv actuator? i think one of those are preventing your boost.

iirc if you pull the vac line off the bbv that will also allow full boost if the actuators not wired in.

is your pcm tuned? you need to tell your pcm theres a sc present or it wont make much boost either.

im thinking the map is the issue. your boost is read via the map on the aeroforce.

adding a boost gauge is not gonna make it make boost.

Oh good lord, you have a cam, ported blower, and some exhaust and a bunch of other stuff and you didn't mention that? As far as vacuum 18-19.5 on stock motor at idle, a cam depending on its specs could have considerably less. I'll have to look at the GT1 specs.

but yeah what Scotty said.

Jeff

even with a cam he should be up and over 10 psi. and hes not even a full top swap really cause n/a heads still.

I agree with you, but you come in with something is so skewed from the norm and don't mention it, well it's hard to give a good answer. If he had come in with a setup with 2" headers maxed out heads and a cam with a 107* LDA and all that he might be down to 8 psi lol.

Jeff

I understand that. It's just we didn't know what you had at all so I would have to assume bone stock. The more modifications you have to increase airflow through the engine the lower the boost will be for the same amount of air the supercharger pumps that's all.