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Low power randomly, have datalogs.

Posted: Wed Aug 18, 2010 5:43 pm
by foliage
So some days my car just feels really quite slow, even if its 10c outside (normally ridiculously fast) it feels doughy with the throttle and it dies in the ass by about 6k as if the ignition has been pulled. Boost rises normally and it revs cleanly with no missing.

Car currently has a 6k rev limit due to standard injectors and afm on an rb25det with gcg highflow running 10-12psi. It is going in for retune in a few weeks but I did a datalog with ecu talk for fun tonight when it was getting slow. Was wondering if someone with some tuning experience could look at it and see if it looks like it is pulling timing? basically its a full throttle run from 2k to 6k. I throttle off at the 5787 point hence the large drop in timing.

http://a.imageshack.us/img821/4129/20010516.png

Re: Low power randomly, have datalogs.

Posted: Wed Aug 18, 2010 10:34 pm
by bachig24u
If your car starts to make 7 psi at 4000, It looks fairly normal.

Re: Low power randomly, have datalogs.

Posted: Wed Aug 18, 2010 10:44 pm
by foliage
bachig24u wrote:If your car starts to make 7 psi at 4000, It looks fairly normal.
It is on full boost around 3800 rpm in 2nd gear. Guess I will have to wait until it is on the dyno until I find the issue.

Re: Low power randomly, have datalogs.

Posted: Thu Aug 19, 2010 11:03 am
by bachig24u
try taking a few degrees out when the engines boosts over 7psi and retest.

The engine may be on the verge of pre-detonation sometimes.
Different environmental conditions maybe pushing it over the edge from time to time.
If the knock circuits are triggered it may be the reason for the intermittent power loss.

Re: Low power randomly, have datalogs.

Posted: Thu Aug 19, 2010 11:19 am
by foliage
I logged knock as well and it never went over 30 for the entire testing period. Is this considered high?

Re: Low power randomly, have datalogs.

Posted: Thu Aug 19, 2010 12:38 pm
by bachig24u
I can't really comment on that as too many variables are in play.

I can tell you that it only takes one at the wrong time to blow a hole in a piston or
the head gasket to spit a chunk out the side though.

Sime