I recently upgraded from GT610 to GT660 mainly to protect engine with more fuel. After the install the car runs perfectly without any CELs.

What I noticed was the car under WOT is actually a little slower on my P Box than it was with the prior kit. Specifically it is slightly faster at lower RPM but dies so much up high to the point where the overall effect is slower acceleration times. The car boosts slightly higher on the stock guage than it did with the prior kit but Iam not getting the levels reported by others even running race gas. The car has the EVOMSit programming so it should recognize the race gas.
My first guess was a small boost leak. On inspection we found a loose hose under the rear BOV which we tightened without improvement in performance. We put smoke in a hose on top of the Y-pipe but got no pressure in the system since it all came out the air filter. No leaks were seen but without pressure I have little confidence in the result. (Multiple different searches here revealed a lot of discussion but no detailed DIY for boost leak testing.)
I have a durametric program and I datalogged the car. The lambdas were perfect with 0.79-0.81 both banks at the redline. I probably need to log other parameters but am not sure which ones.

1. Can someone give me an algorithm to attack this problem starting with the most likely problems and working forward to most unlikely?

2. Can someone give me some idiot proof instructions of the easiest way to do pressurized boost leak testing?

3. I have driven the car ~100 miles since the install. Is it possible that the ECU needs more time to acclimatize before it allows full performance? (I feel this unlikely)

4. Which Durametric parameters would give me best info for examining this problem?

Thanks for any advice you may have!!

 

Mike, the first thing I would do is get a new map.

 

He just got a new map, so that shouldn't be the problem.

Mbailey, what is included in the gt660 that isn't in the gt610 kit?

 

All that I added were added was 60lb injectors, new fuel rails, and new program to control them.
GT660 kit includes headers but I already had them...

 

Iam going to call them Mon...

 

Want to update so if someone else has similar problem they can review the thread and solution.
The problem was not boost leaks or plugs but rather a lame ecu program. Once ecu flashed car runs like a champ.

 

Glad you got it resolved , my first guess would of been the map also.

 

Ah ha so I was right! Glad to hear it Mike. Can't wait for the new 60/130 times.