Those of you following my thread of http://www.turbobuick.com/forums/ge...01-so-heres-update-how-my-car-runs-track.html will recall I am having issues with trap speed drop off. Some of you have said to check the cam, a few of you thought maybe the valve springs were at fault.
I still don't know for sure what the cause of my trap speed drop off is, but I think I may have found one of the reasons why my car keeps dropping trap speed at the track, as last Sunday it felt like the car was stumbling when it hit about 5000 rpm.
Tonight I decided to do a test. I took the car out and put it in 2nd, and let the rpms go up to 5000. I just let it gradually build rpms, I didn't even get into boost.
At 4300-4400 it started to lightly stumble, and at 4800 it was stumbling pretty good. it would still continue to climb in RPMs if I pushed it.
Then I did another test where I put the car in 3rd and I got it up to 4300....didn't really feel anything....then 4400....didn't really feel anything...car was still pulling strong...but right about 4900 it started stumbling like crazy. I did get ito the boost a little on this test.
All of my RPM readings came off the Scanmaster. I did an ohms check of the coil right after the run....I got readings of 12,200 on two of the coils and 11,970 on the other....I read the coils should be between 11,000-13,000 ohms. So I will presume my coil is good.
What about the module? Does this sound like a module issue?
I have a powerlogger...will it display if the ignition is the cause of the stumble?
What else should be checked for a stumble at 5000 rpms?
I wonder if this is why my trap speeds kept gradually dropping off...?
I still don't know for sure what the cause of my trap speed drop off is, but I think I may have found one of the reasons why my car keeps dropping trap speed at the track, as last Sunday it felt like the car was stumbling when it hit about 5000 rpm.
Tonight I decided to do a test. I took the car out and put it in 2nd, and let the rpms go up to 5000. I just let it gradually build rpms, I didn't even get into boost.
At 4300-4400 it started to lightly stumble, and at 4800 it was stumbling pretty good. it would still continue to climb in RPMs if I pushed it.
Then I did another test where I put the car in 3rd and I got it up to 4300....didn't really feel anything....then 4400....didn't really feel anything...car was still pulling strong...but right about 4900 it started stumbling like crazy. I did get ito the boost a little on this test.
All of my RPM readings came off the Scanmaster. I did an ohms check of the coil right after the run....I got readings of 12,200 on two of the coils and 11,970 on the other....I read the coils should be between 11,000-13,000 ohms. So I will presume my coil is good.
What about the module? Does this sound like a module issue?
I have a powerlogger...will it display if the ignition is the cause of the stumble?
What else should be checked for a stumble at 5000 rpms?
I wonder if this is why my trap speeds kept gradually dropping off...?