Question about how much boost I'm running?

[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?

[Scottydoggs]

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.

[coolone]

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?

[SgtMarshal]

boost is the presence of restriction to air flow, so having higher levels of boost may not be a good thing. I was getting 12 lbs on a 3.2 pulley with a full size intercooler

[J57ltr]

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

[Scottydoggs]

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

[J57ltr]

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

[SgtMarshal]

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 a series 3 gen 5 supercharger is a pretty small pulley. probably need a bunch of supporting mods to run that for a long period of time. I'm guessing that with 15 lbs of boost you didn't have an intercooler and a cam to support that pulley.

[J57ltr]

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

[SgtMarshal]

glad to hear

[Tonkin2000GT]

My mods are GT1 cam, ported heads, 90 valve springs, bored .020 over, it's a ssm90 setup L36 block but I went with the gtp setup with the pulley and I'm using a SFI crank pulley, zzp ported LIM, gen 3 blower inlet and outlet ported by zzp, N* Lq4, slp intake, zzp front and rear power log, zzp 3" downpipe without cat, slp 2.5" loudmouth catback, no egr, no evap

[Tonkin2000GT]

How much vacuum do you guys have?

[Scottydoggs]

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.

[Tonkin2000GT]

Yea the car was a gt NA zzp does my tune. I have a L36 single bar map sensor it won't read through the aeroforce interceptor gauges that's why I hooked up a autometer sport comp 2 boost gauge instead of having to send my pcm back right now and have it tuned for a L67 map plus I wanted a mechanical gauge for the pillar.

[Scottydoggs]

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.

[J57ltr]

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

[Scottydoggs]

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.

[J57ltr]

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

[Tonkin2000GT]

Yea well I didn't put the boost gauge on to make more boost? I put it on to moniter how much I actually have. Zzp says the L36 single bar map sensor has no affect on anything as far as hp the only thing is I can't read my boost from it because obviously a L36 NA wasn't meant to have a supercharger it stops at zero.

[J57ltr]

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.