I was at the track this past saturday, and noticed a crackaling sound around 5700~6100 rpms, What is it? MIsfire? valve float?
My shift points are 5900-6000 @ WOT and after the tranny shifts the sounds go away.

 

It could be a broken tranny mount. I would get under the car and check it.

 

I had a friend watching the run and he said he heard it too, Would a broken tranny mount be that loud?

 

sounds like a missfire in my opinion. But it could be alot of things. What were your et's? And could you pin point where the sound was coming from?



OFF SUBJECT......

Hey ION, I've shot you a few e-mails man. I need a tune. And I finally did the OBD-I conversion. How can I get a hold of you? Should I just PM you again?

Mike

 

Mike,
when did you email me? I don't think I got anything from you. Please resend again to tuner@madz28.com and I'll reply promptly.


As for the tranny mount, if it is broken, it can be very loud.

 

The weather Saturday was Hot and muggy but 12.6 and 12.8. those were the times when I heard the noise, but i ran a 12.3 and didn't hear it.

I do spray from 3000~5700 but the noise come when it stops spraying

 

e-mail sent TY

 

Dude thats pretty scary if that is valve float.

I would start off with looking at the trans mount as he said before. And then check you plugs from there. OPTI's have been known to mess up in the upper rpms causing spark issues. Which would sound like a crackling noise from the exhaust note, or even a back fire.

Is there a way you can run some logs on the car durring the passes?

 

Same symptoms I had/have. I would bet it is valve float. I had the same exact circumstances that you are having and it happened at the track as well. It feels like the car is going to cut out up top and sputters, then after the shift it is fine until you hit redline again. I cahnged my valve springs and all better. Valve float for an extended period of time will cause engine damage so be careful.