Before I take my car in for tuning I'm trying to do extensive datalogging to make sure the cam is getting as much air and exhaust flow as it needs. I did some initial datalogging with HPTuners (yes, it's an LS1 program but it can scan OBD2 LT1 cars) and I found that at WOT the MAP sensor is barely making it to .9kPA, which converts to about 3" of vacuum... and that's running at a pig-rich 11:1 A/F ratio. The only thread I found on this topic was here.

Here's my intake setup:

GMPP stainless steel CAI (looks just like SLP)
Unported, unmolested MAF
TrickFlow ceramic coated elbow
NOMAD-ported 52mm TB
Unported stock intake.

Pic of ports on my heads vs. my intake.

The car has a stock bottom end. Complete mods list available here.

Where's the restriction in the setup? I'm guessing the intake manifold.

Thanks guys!

 

You mentioned that your throttle body was ported but was it matched to that of the opening in the intake manifold? If not then that maybe what you need to get it working right. Others should have more suggestions to offer. Good luck getting it all straightened out.

-brian

 

58mm throttle body...

 

The intake comes with the holes setup up for a 52mm from the factory. Do you have headers?

 

Yes, I have headers. Kooks LT's with a Hooker catback.

Here's the car's setup: http://promba.googlepages.com/mycamaro

 

Dirty air filter? Is there an airfoil on the ported TB? Did you verify the TB ports are concentric with the holes in the intake manifold (no "overlap")? Did you confirm the TB blades are at a 90-deg angle when your foot is on the floor? Did you verify there was not a mat under the pedal? Did you check the MAP sensor gasket to make sure it is intact? Any possibility the valve are not adjusted correctly?

 

EDIT -- took the filters (plural--SLP style CAI) out tonight. Soaked them in soapy water and rinsed them out... turned out they were filthy. We'll see if that was contributing to the problem...

Yes.

Yep, it's just about a perfect matchup.

Yes.

Floor mat clearance is within the GM specifications

Yep... looks good.

I'll verify that this weekend.


Thanks for the replies guys! Keep 'em coming.

 

not to hijack thread, but when you say map sensor gasket, do you mean the round rubber little thing that fits over the map tube?
or is there another gasket. plus my round rubber is worn out, any idea where to get another one? did not come with my new map sensor.

 

Yes that is the gasket. You can get it from GM for 4$.

 

sorry to hijack, why the question on airfoil on a ported tb?

 

If it's a stock ported tb, then it doesn't have the airfoiled center piece cast into it like the 'real' 52mm, 54mm, 58mm tb's have. It's the stock tb with slightly larger bores and butterflies.

 

The NOMAD piece included an airfoil. The blades are razor-thin too... I'll post pics later tonight.

I edited my reply to Injuneer last night... the air filters were REALLY dirty. I mean, horrible, awful, amazingly dirty. That car was probably choking for air up top. In the past, tapping the filters on the ground was enough to shake off the gunk on the outside, but there was still a bunch of dust and dirt stuck in the actual fabric. I soaked them in a bucket of soapy water for 15 minutes, rinsed them out, and repeated that about 3 times. Each time the water was BROWN! The filters are WAY cleaner now.

Even if that doesn't alleviate the vacuum issue, the car will breathe much easier up top. Hopefully that'll help with the problem.

 

The airfoil smoothes flow slightly and reduces pressure loss. Not much though.