ok so heres the jist of it. my car has been sitting for almost two years getting some body/paint work done. I just drove the car for the first time a few months ago and again today. i put my boost gauge in and ran the car and only saw 4lbs of boost...... Vortechs website says i should get like 7-8psi. Just wondering what it could be. Loose belts? Bad fuel? Airflow? Leak? Gauge? the car is still not completed so i cant test and tune it daily. just wondering if anyone knows what the problem could be?

many thanks in advance

 

it could be any one of those things that you mentioned.

boost leaks require detective work that cant be done over the internet.

 

its either a leak or belts slipping, bad fuel doesnt determine how fast your blower spins and boosts.

 

Humm try Push more harder.

Edit: What size ur exhaust? And running header? Tp?

 

yea on my grand prix i did headers and it lowered the boost but i dont have that for this car. just the nismo catback exhaust and high flow cats. Now i messed with the cog belt cause it was really loose and someone who i work with said that could be it. Tightened it but got nothing. another day ill try another gauge. the one i have is a defi....

im going to end up getting a smaller pulley(3.12) and cog(34tooth) but i want to see whats wrong before i do that.

 

so you have a non-revup with a 3.33 pulley?

you arent going to get 7-8 psi with that. maybe 5. i doubt you have anything wrong.

 

Do a boost pressure test and make sure your belt is tight and let us know.

 

Vortech I thought said u get 7psi out of the box? I'll do the test as soon as I can.

 

does the supercharger have a wastegate? if so what if its not allowing more then 4psi? is that even possible?

 

no thats not possible.

i dont think anyone knows when/if the bpv releases overboost. You'd have to run straight from the blower to the TB to even get high enough pressure to test (ie >17 psi)

plus you could hear it if it was leaking.

 

You're very likely to be running less boost because of your exhaust. Once you free up the exhaust with an SC setup, your boost pressure will decrease, yet you can make more power.

That's probably not the whole reason, because 4PSI is unusually low. You have something else going on as well.

The BPV that comes with the kit does not release pressure for over boost - the point of a BPV is to hold closed under boost, never to release until the MAP goes into vacume.

 

Iam running the 2.87 and iam only seeing 5psi... I gotta check my belts and do a boost leak test. It was definitely running higher when I first got it tuned. It felt stronger too.

I dont think the nismo exhaust can lower the psi by that much. Can it? I have the nismo exhaust and testpipes.. I did 415/370rwtq

 

What was your boost pressure at these #'s?

 

i want to see what 2 years worth of bodywork/paint looks like

 

Wow .. Vas, you have some issues then. I'm hitting 11PSI peak with my 2.87 setup, including exhaust, headers and test pipes.

With those numbers you have to be around 10-11PSI range when you got tuned. Check your belt tension, it stretches and subsequently loosens over time and needs to be checked every few weeks.

 

if it was slipping that bad, it would squeal like a pig at startup!

 

Don't u have gtm pulley? Humm 5psi is very low with 2.87. I feel like you have a boost leak. What size belt you running?

Edit: btw your exhaust is fine. I have 2.5 td with 3.12 pulley. And hitting up till 7-8 psi if I push hard.

 

I know its either sliping or leaking somewhere. because the first day I got it.. it was like holly hell. I would break loose in top of 3rd. Now I get full traction in 2nd lol. I mean its still fast as hell than NA and its kinda fun at the same time to be able to hook it up. but I do miss the pull .

5 psi is deff low. Iam going to remove the belts and clean them with rubbing alcohol n test it like that. if no luck, iam going to do a boost leak test next

 

It definitely sounds like a belt issue, but yes, headers and highflow cats/test pipes will decrease boost on the vortech.

 

chef,

Yes I do!. There is a little oil coming from the back of it and also some in top of my hood. So my seals are going bad. and there is some mist in the back of the blower where the cog is. Iam also 90% sure its that, thats making it slip. Iam going to keep it like this for just another week untill I sent it for the 65K rebuild .

as far as belt size iam not sure. I have tried a whole bunch untill it was the right one. The pulley belt is fine and its strong as hell. the cog belt in other hand lol