Hesitation around 6krpm on track
04-30-2010, 05:36 PM
#1
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Hesitation around 6krpm on track
First time out with the turbo this year.
Steering heavy and not straight, incorrect front toe, yet 4s faster than last year.
Some engine issue I need to look in:
Car runs great and pulls like a train. However, from 6krpm to 6.5krpm is feels like running into a slight wall* and then it goes like normal fom 6.5 to 7k. Repeatedly.
*) I will loose acceleration, not speed.
Co-driver commented that slightly lifting throttle restored action.
Thought I made a log, but it's not on my notebook, so I will try again.
Can we rule some things out or pinpoint this yet?
My first guess is spark blow out.
Steering heavy and not straight, incorrect front toe, yet 4s faster than last year.
Some engine issue I need to look in:
Car runs great and pulls like a train. However, from 6krpm to 6.5krpm is feels like running into a slight wall* and then it goes like normal fom 6.5 to 7k. Repeatedly.
*) I will loose acceleration, not speed.
Co-driver commented that slightly lifting throttle restored action.
Thought I made a log, but it's not on my notebook, so I will try again.
Can we rule some things out or pinpoint this yet?
My first guess is spark blow out.
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05-01-2010, 03:33 PM
#4
Cpt. Slow
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No stumble or hiccups? If you're not on cops I'd say plug wires. I've had about 50 million symptoms that ended up being bad wires, so obviously that's what's wrong with everyone elses car. If you're going COPs I'd say you're going to be okay.
You said the wiring was bad, did you switch back and forth from cops? Did you change dwell settings?
You said the wiring was bad, did you switch back and forth from cops? Did you change dwell settings?
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05-01-2010, 04:10 PM
#5
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The plug wires are about 1 yr old with track only miles. Could be... I'm going for the COPs anyway.
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07-04-2010, 10:58 AM
#6
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Still same issue today:
a) Power loss between 6000-6500rpm
b) Dip stick sticking out <1/2 inch after the run
What I did before today:
Downed the boost to 0.9bar (13 psi).
Reverted to default crankcase vents instead of small filter.
Current MSQ attached
MLV from today (at a local track during a demo run) attached in ZIP.
OEM Ignition, new wires
New BKR6E plugs, default gap (not the -11 version)
What is going on?
a) Power loss between 6000-6500rpm
b) Dip stick sticking out <1/2 inch after the run
What I did before today:
Downed the boost to 0.9bar (13 psi).
Reverted to default crankcase vents instead of small filter.
Current MSQ attached
MLV from today (at a local track during a demo run) attached in ZIP.
OEM Ignition, new wires
New BKR6E plugs, default gap (not the -11 version)
What is going on?
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07-31-2010, 12:18 PM
#8
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I need suggestions here... I have a log, msq, everything. Seem to do it only when hot, so not the first 1/2 lap 
Bad (OEM) ignition will do this? I need COPs, is anyone doing PNP kit at the moment?
Bad (OEM) ignition will do this? I need COPs, is anyone doing PNP kit at the moment?
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08-01-2010, 02:22 PM
#12
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I had a similar thing at our last dyno session and it turned out I forgot to properly tighten the coilpacks to the valvecover.
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09-26-2010, 03:48 PM
#16
I'm subscribing to this. I dynoed this weekend and have a intermittent drop at 6k. No matter what we adjusted it would show up at the same rpm. 6k. It lasted for .3s and then picked up like it never happened. I think it is my cop harness. I'm rebuilding it. Sometimes you could feel it, then the dyno graph showed how bad the drop was. Then the next pull might be perfectly clean.
I'm looking into my dwell settings.
I'm looking into my dwell settings.
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09-26-2010, 04:57 PM
#18
Mine was hot as well. Didn't start seeing it until we were doing high rpm pulls. When it happens it is at the same spot. Before and after intake cam gear adjustment, timing, fuel, etc.
We gapped down the plugs at firs thinking the spark was being blown out. Let me know if changing the plugs has an impact.
We gapped down the plugs at firs thinking the spark was being blown out. Let me know if changing the plugs has an impact.
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09-27-2010, 03:35 AM
#20
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Break down:
Blow by from rings (leak down)
Blow by from valves (leak down)
Dead CAT (inspect)
Spark blow out (try extended reach plugs with smaller gap: .025")
Dying CAS (no spikes in log, not likely)
Blow by from rings (leak down)
Blow by from valves (leak down)
Dead CAT (inspect)
Spark blow out (try extended reach plugs with smaller gap: .025")
Dying CAS (no spikes in log, not likely)
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