vetteguy11

I have an STS twin turbo set up on my 02 C5 convertible which I run at 12lbs of boost with methanol injection. It was tuned at the shop that did the install with the diablo sport tuner. It runs great and the power is phenominal but I notice a puff off blue everytime I shift at high boost. If your not familiar with the STS set up, it's a rear mounted turbo system that fits where the mufflers used to be.

Because of the unique set up, which has many advantages, I no longer have mufflers only about 6 inches of exhaust pipe. The turbo's now act as mufflers and I get an incredible sound. I am wondering if, because I no longer have mufflers, that there will always be a puff of blue at WOT because there is nothing to filter those spent gasses. The tune is supposed to be right on and STS techs gave us all the parameters which we meet right on. The plugs are super clean and everything else is right on so I'm just curious if I'm just being too ****. It's not a problem as long as it's not a problem.

jmoody66

Are you running 12 lbs of boost on a stock bottom? Just curious because I was told I could up the boost from 7 to around 10 or 12 and I would be fine with a good tune.
I would suspect that your tune is just on the safe side and when you floor it that is extra fuel being added. Im not the pro but Ive heard of this.

z06 vett

could be a few things.i would guess oil in the intake manifold by way of PVC .look into PVC set ups and catch cans.i am hoping for 10psi with meth.i hit this kind of boost by accident a couple of times.7-8 psi i is pushing it with the ls bottom end.12 lbs.can be done ,from all that i have read ,with race fuel or 93 octane and straight methanol.i still have yet to solve the tune problem.i have had oil in the intercooler,to much oil pressure on the turbos,oil on the maf and oil blow by under boost resulting in oil out the oil breather.i baffled the filler tube and put a catch can in between the intake to TB .mike

vrybad

Blue sounds like oil.

THE TECH

I will be doing the same setup in two weeks. I will use the Predator to put their tune on but will go to a local tuner to get the car dialed in as the Predator is somewhat of a generic tune to get you going.

bvillezo6

If youre running a TT set up you DEFINITELY need to go to a tuner and drop the $$$ for a full blown tune. otherwise youre not getting your moneys worth out of your TT.

Jim

gr8vet

Holy crap, I wanna hear more about this 12 psi boost on a stock bottom end. I would guess your smoke is coming form oil into turbos, blow by, it is normal. Did your installer add the check valve to PCV line? Verify PCV electronics are working correctly.

I have been warned to not go above 9 psi boost on stock bottom end with meth. I am running a sweet 5 psi boost on mine.

TNTC4VETTE

More than likely this is either a symptom of too much backpressure in the system (inadequate scavenging on the pump side), or the seals are going south in the turbos. Is the backpressure alarm ringing in the car? Also, is your STS pump still on the high/low solenoid, or have you wired it to be permanently on high flow?

I had major let-off blowby when I first bought my system (used). Turns out the turbo was both not what I was told, and was shot. Replaced the turbo with a 76GTS, and still had puffs of smoke. I had Mike Norris install an in-line restrictor (.058 nitrous jet) pre-turbo, and the smoking all but stopped.

Mike also did a very conservative 550/550 tune for the street. Plenty of fuel and room for big boost when I want to. Even with the lopey cam, it is very drivable, and part-throttle is what most tuners miss. He does the entire range, not just WOT for big #'s.

Did it look like this? (Near the end of the video...rest is just fluff...)

http://www.youtube.com/watch?v=4BpcaSa8LZg

And here's a little sample of too much of a good thing on our beloved LS6's. (Lost WG reference on the turbo...#7 ringland went bye-bye and cracked the block.)

http://www.fquick.com/videos/viewvideo.php?id=3432

Hope this helps!

-Ronnie

edcmat-l1

I've tuned several of them. The latest was a C5 that made 561/530 something.
Anyways, the STSs have oiling issues. Everyone with exp with them knows that.
I would look into your return system. The recommend cutting out the low speed, and going just with the high speed return (for lack of a better term.)
They have you remove the resistor in the power feed to/from the relay. Something like that.
BTW, with a stock bottom end, and 12 psi, I hope the tune is spot on. Get yourself a wideband, so you know EXACTLY what the A/F ratio is under WOT.
Hope its a 2 bar SD tune too. 12 psi is ALOT to depend on your MAF to get the fueling right, which it never really can.