Troubleshoot this ...
Troubleshoot this ...
Somebody sent this to me, power level goes flat AFTER the VDI opens, stays well below peak power level prior to opening. Cobb AP, high flow cat and rear exhaust, RB intake
Other curve is a factory stock RX-8, same day/dyno
This should be interesting (or more likely not given the usual forum parrots
) ...
Other curve is a factory stock RX-8, same day/dyno
This should be interesting (or more likely not given the usual forum parrots
) ...
I had one looked almost like that when my CAT was getting plugged up...but I would expect it to be lower before the APV opened as well.
Is the VDI actually opening?
Spark?...missfires? AFR?.....any indication it is running out of fuel? P2's?
Is the VDI actually opening?
Spark?...missfires? AFR?.....any indication it is running out of fuel? P2's?
the curves between the two cars is mirrored through the VDI operation until 7500 rpm ...
WOT dyno run, You don't think the P2s are already engaged prior to the VDI opening?
.......AFR's? are they "normal" stinking rich...or tuned?
Administrator
Joined: Jul 2002
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From: portland oregon
my first question too. i hear you team , for that 250 of rpm they are the same but that could be turbulence from the barrel VDI trying to open and then not fully opening or even slamming shut again
do you have AFRs?
do you have AFRs?
Last edited by zoom44; Aug 6, 2011 at 12:34 PM.
Administrator
Joined: Jul 2002
Posts: 21,958
Likes: 115
From: portland oregon
ive always seen it as a problem with the pickup itself but the last dyno day around here Jeff did identify an ignition issue on one car that looked like that. is it possible to tell the difference on the graph here without scoping the car itself
Last edited by zoom44; Aug 6, 2011 at 08:54 PM.
Rockie Mountain Newbie
Joined: Mar 2011
Posts: 1,601
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From: Denver, CO
Loose spark plug wire connection, either at the plug, or at the coil.
At lower rpms, the resistance in the combustion chamber is low enough for the electricity to jump the wire to plug gap, and then the actual spark plug gap, and still create a proper combustion event.
As the rpms get higher, and the mixture is richened, the resistance at the plug increases to the point where the spark goes to ground at the loose connection point, usually shooting around the spark plug instead of through it.
BC.
At lower rpms, the resistance in the combustion chamber is low enough for the electricity to jump the wire to plug gap, and then the actual spark plug gap, and still create a proper combustion event.
As the rpms get higher, and the mixture is richened, the resistance at the plug increases to the point where the spark goes to ground at the loose connection point, usually shooting around the spark plug instead of through it.
BC.
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