Need tuning help!!

[wahoo50]

When I get to about 1/3rd throttle and just start to build boost, I begin to hear a rapid fluttering sound, as though it's coming from the air filter. Also see lots of black smoke at the same time. Idea's anyone?

[441120]

Running too rich or maybe wastegate opening too early?
What's your fuel pressure? Block learn? Knock?
Intercooler hoses/clamps loose, check all the hoses from the turbo to the throttle body.
Good luck!

[wahoo50]

Fuel pressure set at 40lbs. Have just gotten the car running with a FAST system which I do not know how to program. Sure would like some pointers on how to set it up. Has 72 lb. injectors. Thanks for the reply.

[buickpower]

try posting this in the performance ecm upgrade section of the board, it might be more of what you are looking for.

[mcponch]

Could Your Air Intake Be Colaspeing? Don;t Know If Thats Spelled Right? Frank.

[wahoo50]

Thanks for the reply. Don't think so as I'm using a 3" pipe with a 9" K&N filter.

[441120]

Does boost gage flutter also?

[wahoo50]

Guage does not flutter. Have solved part of the problem by determining the fuel pressure gauge was reading incorrectly. Reduced the pressure from 55lbs. to 40 lbs. with the vaccum hose off, stopped the black smoke. If you accelerate past the fluttering it will continue to build boost.

Located a broken ARP exhaust header stud, am thinking this is creating the sounds. Now to figure out how to reomve a broken stud from an aluminum head.

Thanks for your help.

[dvernst]

Yeah my car makes that same sound if I hold it around 8-10 psi everything seems to be running o.k. on mine though.

[wahoo50]

After further investigation, it starts fluttering about 5 lbs. boost, guage does start rapidly bouncing. Fluttering and guage bounce stops at 10 lbs. boost. Ideas anyone? Problem not caused by exhaust bolt being broken.

[441120]

What kind of wastegate control are you using? Factory solenoid? Aftermarket?

[jimmymopower]

Originally Posted by wahoo50

After further investigation, it starts fluttering about 5 lbs. boost, guage does start rapidly bouncing. Fluttering and guage bounce stops at 10 lbs. boost. Ideas anyone? Problem not caused by exhaust bolt being broken.

Sounds like compressor surge. What combo are you running? It usually pops up after switching to a front mount or even an oversized stock location intercooler. You may be able to tune some of it out, but for the most part people tend to change their driving habits. Do a search on compressor surge, lots of people out there with the same problem.

[wahoo50]

Thanks for the inputs, car has THDP with external wastegate controlled inside the car, original intercooler. TE-60 turbo. 3,500 rpm stall converter.

[gnx139]

Dude, you got the SURGE! I got it after putting on the PTE S.L.I.C. It sucks and I hate it. If there is a way to tune it out, someone please tell me. I will be putting on the GT3255E and see if that helps. Car now has a TA48 which is the predecessor to the 49. Mine does the same thing at 5psi at part throttle.

[TurboBuRick]

Originally Posted by gnx139

Dude, you got the SURGE! I got it after putting on the PTE S.L.I.C. It sucks and I hate it. If there is a way to tune it out, someone please tell me. I will be putting on the GT3255E and see if that helps. Car now has a TA48 which is the predecessor to the 49. Mine does the same thing at 5psi at part throttle.

Is it making the car stumble when it happens or is it just the noise you guys dont like? What MAF are you running? Stock?

[gnx139]

The boost actually bleeds out and the car stumbles. It will not maintain boost at 5psi or under unless you put the accelerator into it more. It does not like part throttle boost for some reason. I can only guess that the large amount of air in the large IC over pressurizes the compressor and forces the air back out unless the compressor is pushed past the volume in the IC. That is how the SURGE was explained to me.

[TurboBuRick]

Originally Posted by gnx139

The boost actually bleeds out and the car stumbles. It will not maintain boost at 5psi or under unless you put the accelerator into it more. It does not like part throttle boost for some reason. I can only guess that the large amount of air in the large IC over pressurizes the compressor and forces the air back out unless the compressor is pushed past the volume in the IC. That is how the SURGE was explained to me.

What MAF?

[gnx139]

Stock original MAF, I put on one of the reman-Delco units from the dealership and same thing.

[jimmymopower]

Are you running the stock throttle body? Heads? The turbo is producing more air than the engine can use at part throttle. The charge actually "bouncing" off the TB and being pushed backwards through the turbo and stalling it, causing the surge in boost psi. There is a thread on the other board where a guy is using one of those cheesey "tornado" things at the turbo inlet to help with surge, and he says it actually works.

[TurboBuRick]

Originally Posted by gnx139

Stock original MAF, I put on one of the reman-Delco units from the dealership and same thing.

Well the way I fixed that problem on my car was simple. I moved the MAF.
But you can't do that with a stocker. I simply took it out of the path of the unused air. Moved LS1 MAF into my up pipe and eliminated that exact problem.
Whos chip are you using. The programing in the chip should take care of this. Thats what I've been told. The other option I here is a blow of valve. I already had the LS1 so I got some clamps and couplings and BINGO, SMOOTH AS GLASS at any amount of boost. You can still here it CH CH CH CH but you can't feel it.

[TurboBuRick]

Here is a picture.