Thread: Low boost! 10 PSI on a 3.0

Ive been chasing a low boost problem for a while now, and ive checked everything from vac leaks to gauge problems to egr problems. I checked everything that i thought it could possibly be and after finding nothing i decided that it had to be the super charger. I had my supercharger ported and i thought that maybe something happened to it during porting that was making it unable to make boost. So i finally bit the bullet and bought a supercharger that i knew was making boost. I put it on with the 3.0 pulley still attached and im still only making around 10 psi of boost.

Any suggestions on what to check would be very appreciated, even something off the wall that could be going on would be helpful. im at at dead end atm. I have a tech2 scanner as well that ive been using to monitor KR and alot of other data. I have 0 KR with the 3.0 making 10 psi.

Setup is a s1x cam, speed daddy headers, ported heads, and all other supporting mods, plugs, wires ect.

-Something else that is worth mentioning though is that i have my lower intake machined for an IC and im not running one. Im not sure if that could effect boost or not.

I think you're fine. When you cam it, things flow so well that boost looks low.

I told you there was nothing wrong with that supercharger and that flowing that well would make boost low. If you are making good power what does a boost number mean?

Because im not making the power i should be, it runs strong but it only ran a 14.09 at 98 with a 2.21 60 in the 1/4. And Im pretty sure i could run a 2.8 pulley and run 12 psi with no problems. That dosn't seem right to me.
Trans has 3.29 gears also, so for the setup i have not being able to spin the tires at all when i punch it going 20mph im lacking power somewhere. Timing tables are stock and at WOT its not pulling timing, so its not a timing issue or torque management issue.

Did you know zoomers car that makes ~450 WHP with a Gen V M90 also makes 10 PSI?

Your 60 is quite high. Work on that.

http://www.grandprixforums.net/timeslips.php

98 mph trap speed seems low though.

How much timing are you running?

Yeah the car just seems like it isnt making the power it should be, like i said if i floor it going any faster then an idle it dosnt spin the tires at all. Ill drive it and check timing again to give you exact timing numbers but i think i remember seeing 15-16 degrees at wot. What ever stock timing is.
Ive checked around and it seems like people who are cammed with headers are running around 10-12 psi with 3.2 pulley and some can run a 3.1 with a good tune. I just have a standard tune though and my stock injectors arent even closed to maxed, only seeing around 17.xx MS on inj pulse width.

If i was making the boost i should be with a 3.0 then yeah my injectors would be maxed. But like i said im only seeing 17.xx MS on inj pulse width and from what you told me and what others have said im good until at least 21 MS. Even then it shouldnt matter unless im going lean enough to knock, and i have 0 KR. The previdous owner of my car went 13.7 with a 3.4 setup, i dont know his 60 or MPH tho. So i know that something is up with my car, and i could blame it on the tune, but that dosnt explain the boost thing.

So still no suggestions on what it could be?

so with my only real mods being s1x cam, headers, and ported heads i thought running a 2.8 would be pretty much unheard of. I thought a 3.0 was really pushing it. Usually people running under a 3.2 have a cam and IC or atleast an IC. Well, im not quite sure what to do atm, i guess ill just run it as is and try and crank the timing as much as possible. It just dosnt make sense to me that my injecors arent closed to maxed. Has anyone ever heard of someone running a 2.8 on stock injectors? seems crazy.

That is true, and i did spend alot of time on the heads and did a ton of research before i ported them. The car still has a lack of power even tho it runs well.

I dont know ifthis is your problem but my bbv was messed up on my car and was only runing about half boost i fixed it and now boost gauge is maxed out check your bbv

that typically leaves you with 4-5 psi, not 10.

yeah, and when i was low on boost that was the first thing i went to and i was convinced that it was the problem somehow. Even with it disabled boost dosnt change.

Im also only getting 13 mpg, but i dont think im running that rich. where should my o2s be? I have both my o2 sensors working but i have no cat. Could this be causing a problem?