Need brainstorm help in why car is rich, no changes in mods
9 Second Club
Joined: Nov 2003
Posts: 13,616
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From: Norn Iron
Are you a MAF obsessive who's never actually tuned SD ?
It's all basic physics. Nobody is ever going to change that.
The sort of statement you just came off with sounds like some BS that one single ecu maker in the world keeps spurting out in order to justify retaining or buying one of their MAF units for their ecu
It's all basic physics. Nobody is ever going to change that.
The sort of statement you just came off with sounds like some BS that one single ecu maker in the world keeps spurting out in order to justify retaining or buying one of their MAF units for their ecu
Are you referring to cylinder charge temperature table? Mine is disabled and my afr may fluctuate +/- .3 from the changes in weather from the seasons. It's not a big deal to modify the VE table to fix it.
But IIRC, when he said he tuned his car on the dyno he only adjusted the PE table/IFR table and didn't mess with the VE table. So....
But IIRC, when he said he tuned his car on the dyno he only adjusted the PE table/IFR table and didn't mess with the VE table. So....
9 Second Club
Joined: Nov 2003
Posts: 13,616
Likes: 185
From: Norn Iron
Ive never used the factory ecu on these cars, so if there are limitations in what it can do, then that is a bad thing
But yes of course charge air temp compensations should be set appropriately. As indeed should every aspect of tuning an ecu.
If you only look at one small section, then you will expect there to be problems somewhere.
But equally you are correct, changes are not huge.
Physics will dictate that for every +18deg F temperature change, approx 3% extra fuel would be required to account for change in air density due to temperature
Likewise subtract for a reduction in temp change.
That is nothing new, and it applies to every single ecu/engine out there. However very few would ever recommend following those rules on a boosted engine when charge air temps start to get very hot, purely for engine safety reasons.
it may be nice in theory to do that to maintain consistent AFR's, but when things get too hot, I'd much rather see things get richer for engine safety. Over about 150degF I'd be returning any compensations to zero, which would in turn create a richer AFR scenario again. Not massively so of course
Of course if you live in a climate with relatively small temperature changes, and you have efficient intercooling...all of the above becomes less important, simply because there would only be small changes in temperature
But yes of course charge air temp compensations should be set appropriately. As indeed should every aspect of tuning an ecu.
If you only look at one small section, then you will expect there to be problems somewhere.
But equally you are correct, changes are not huge.
Physics will dictate that for every +18deg F temperature change, approx 3% extra fuel would be required to account for change in air density due to temperature
Likewise subtract for a reduction in temp change.
That is nothing new, and it applies to every single ecu/engine out there. However very few would ever recommend following those rules on a boosted engine when charge air temps start to get very hot, purely for engine safety reasons.
it may be nice in theory to do that to maintain consistent AFR's, but when things get too hot, I'd much rather see things get richer for engine safety. Over about 150degF I'd be returning any compensations to zero, which would in turn create a richer AFR scenario again. Not massively so of course
Of course if you live in a climate with relatively small temperature changes, and you have efficient intercooling...all of the above becomes less important, simply because there would only be small changes in temperature
