I am going to pick up my Z this afternoon after my Vortech install. I was told by the installer/tuner that the car ONLy put down 343 HP. I dont have TQ numbers yet as I havent seen the dyno charts. Also, the car was only building 6.1 psi of boost at max and the Vortech is supposed to run 8 psi. Does anyone have any ideas as to why the car is not seeing the full amount of boost that it is rated at? I dont think the belt is slipping. At least thats what the shop that did the install said. My engine mods are as follows:

Injen Dual exhaust
Megan racing test pipes
Topspeed headers
Kinetix SSV manifold

I also have the 5AT tranny. I know there are a lot of guys with similar setups that are running over 400 RWHP. I am thinking that if my car was building the full 8 psi then I would be at or above the 400 RWHP I am shooting for. Any ideas would be greatly appreciated.

Thanks,
Zach

 

Maybe it has to do with the temp? What was it? On cooler days I see 8.4lbs

 

What psi are you seeing on warm days? I think the temp was upper 80s yesterday, but not positive. It was also very humid as well.

 

Can he graph boost vs RPM with his dyno? It should be a straight line. If the line curves it will indicate belt slip or a leak in the intake plumbing.

 

Just making sure you don't have underdrive pulley. I know you didn't list it, but I thought I would ask.

Like Underpressure said .. please ask the dyno for a boost vs. rpm graph ... that will tell a lot here

Is the BOV/bypass valve leaking at all ... is the only noise in the engine the exh. and supercharger whine ... or is there a lil psssh too?

 

Just as a reference... I hit 8.5 pounds of boost with RT cats after initial install. Then when the RT cats failed and I gutted them, my boost dropped to 7 give or take. I put the 3.125 pulley on and am now back to 9.1...

It shows that this is all somewhat unpredictable. If you go through the BOV and other checks and end up with less than 7lbs. it may just be your combo of mods... then again, maybe not.

 

I had a similar problem at first and traced it to the BOV. Basically, I get some boost that would plateau around 5 or 6 max and then drop off. Turns out that the BOV was defective and was leaking boost. Vortech replaced it for free and that totally fixed the problem. They told me that a few others were defective--probably a bad run of BOVs. My system was purchased in December, '04. I dyno'd in March and had a full 8 lbs of boost with 372 rwhp with no other performance mods and a minimal tune.

 

I'm barely getting 6lbs of boost right now but I think my bearings are rubbing in my blower.

 

Are you hearing a noise coming from inside the blower? If so, that could mean you've cranked down the set screw on the BOV too much. That will close the bypass too early (i.e. higher than about 4-5" of vacuum) causing surge (back pressure) when you decelerate. This will cause the fan blades to rub on the inside of the blower housing. Metal chips off the blades will then get into the blower gears and bearings and kill it dead. This would have nothing to do, however, with failure to produce boost before any damage results. Failure to produce adequate boost is due to a leak somewhere or to slipping belts--or, a problem with your boost gauge.