Just got back from a test and tune. Last New Years Day ran 12.69 @ 111.81 (2+ sec 60fts). That was with 2 gls of 110 and a couple gls of 93. Probably 50/50 mix. Also, ran 12.83 at 108.8 on 93 pump. Max boost ebc recorded 23.4 lbs. Today, max boost 23.3 lbs., 3 gals 110, only about a gallon 93. Times and power way off.
First pass 1.91 60/ft, 13.06 @103.98. Second pass, 12.92 @106.39. Last pass, 1.82 60/ft, 12.95@ 104.23. Where did my power go? I was faster before on pump gas. I'll get a boost pressure test. Or, whatever else I need to get checked.

 

what kind of temperatures at the track?

 

I know it was over 80 degrees today.

 

Hole in the exhaust about 6 inches before the muffler canister, where a support bar connects. Could this be the problem?

 

boost leak check... i betting some clamps on there are tired and weak

 

Running the stock ecu has it's downsides....Our ecu has multiple maps. If your ecu picked up some knock, it switched maps to a safer one. There are a fewe variables that make this happen. Like I said, Knock, air temp are a few deciding factors for the changes in the map selection...This is a fair safe for the engine and works very well at keeping your engine safe.

 

Is a 1" hole in the exhaust causing the boost pressure leak.

 

If it was in the intake track it would have a boost leak....if it's in the exhaust that would be an exhaust leak.
Yes performance will drop due to the turbulance or reversion created by the leak. Fuel milage will also suffer.

 

Thanks - I hope thats the source.

 

If your car was tuned for race fuel then ok. If it was tuned on pump, you need to run pump.
If you add race fuel, the air/fuels get richer. Adding race fuel isnt going help you run faster unless you can take advantage of the slower burn, increase timing, and decrease fuel.

 

adding race fuel helps when you turn up the boost even on a pump map

 

Got a boost leak test. You were close. Want to thank Big Al for promptly diagnosing the problem. My stock BOV is leaking at 23-24 psi. No other leaks. Looks like its time for the Forge. Appreciate everyones feedback.