Newb Question About Tuning
10-06-2008, 02:08 AM
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Newb Question About Tuning When I bought my car about 3 months ago from a dealer, I met with the previous owner of the car who traded it in. After giving me the lowdown on the car for reassurance with the purchase, he told me the car was tuned by "Frost" at lsxtune in VA, pretty sure he's a sponsor here. The car was supposedly specifically tuned for "reliability", so I'm guessing on a very conservative set up. What does this mean exactly? Does that mean the car is running rich, pulled timing, and is leaving power on the table in exchange for longevity? Does that explain the lower than average gas mileage I'm getting normally mixed and in city? I have no problem pulling off 25-28mpg on all highway driving, but it drops to 14-18mpg if I'm lucky (when actually driving for gas mileage) once it's 50/50 city and highway give or take, and I'm wondering if it's because that's the way it's tuned. The car has been given thorough tuneup, including: newer o2 sensors, air filter, seafoam treatment, spark plugs, oil change, newer pcv valve, fuel filter, etc. I'm told that if I "lean it out", I can extract some more power and better fuel economy by doing so, but if that would jeapordize reliability by doing so, I'd rather leave it the way it is since the car is a daily driver and I'm a poor college student (for now). Thanks in advance people.
10-06-2008, 06:01 PM
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Wow was that Jason's old car (he used to live in VA Beach, moved to LA)... ?
He never knew what cam was in it, though I suspect it was a gm hotcam.
He had initially wanted the car to be good "all around" and said it may see some type of auto-x or road racing (though it never did AFAIK) so WOT is about 12.6ish:1 rather than the more common 12.8-13ish. Timing is not on the edge at WOT to help compensate for rising cylinder temps that could be encountered during such racing as well.
City driving is more about driving style for mileage; understanding DFCO and how to make it go into DFCO usually yields good results.
You can't really "lean it out" for normal driving around since it is in closed loop and doing the fuel trimming itself. I don't recommend open loop for most daily driven cars.
He never knew what cam was in it, though I suspect it was a gm hotcam.
He had initially wanted the car to be good "all around" and said it may see some type of auto-x or road racing (though it never did AFAIK) so WOT is about 12.6ish:1 rather than the more common 12.8-13ish. Timing is not on the edge at WOT to help compensate for rising cylinder temps that could be encountered during such racing as well.
City driving is more about driving style for mileage; understanding DFCO and how to make it go into DFCO usually yields good results.
You can't really "lean it out" for normal driving around since it is in closed loop and doing the fuel trimming itself. I don't recommend open loop for most daily driven cars.
10-06-2008, 07:48 PM
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Wow was that Jason's old car (he used to live in VA Beach, moved to LA)... ?
He never knew what cam was in it, though I suspect it was a gm hotcam.
He had initially wanted the car to be good "all around" and said it may see some type of auto-x or road racing (though it never did AFAIK) so WOT is about 12.6ish:1 rather than the more common 12.8-13ish. Timing is not on the edge at WOT to help compensate for rising cylinder temps that could be encountered during such racing as well.
City driving is more about driving style for mileage; understanding DFCO and how to make it go into DFCO usually yields good results.
You can't really "lean it out" for normal driving around since it is in closed loop and doing the fuel trimming itself. I don't recommend open loop for most daily driven cars.
He never knew what cam was in it, though I suspect it was a gm hotcam.
He had initially wanted the car to be good "all around" and said it may see some type of auto-x or road racing (though it never did AFAIK) so WOT is about 12.6ish:1 rather than the more common 12.8-13ish. Timing is not on the edge at WOT to help compensate for rising cylinder temps that could be encountered during such racing as well.
City driving is more about driving style for mileage; understanding DFCO and how to make it go into DFCO usually yields good results.
You can't really "lean it out" for normal driving around since it is in closed loop and doing the fuel trimming itself. I don't recommend open loop for most daily driven cars.
So how exactly was the car tuned.. if you don't mind breaking it down into further details? Was it tuned mainly for reliability at WOT? All I remember is being told that it was tuned conservatively for reliability all around, so I assumed it's running rich at both WOT and part throttle because I can smell what I'm guessing is unburnt fuel most of the times, but maybe it's because the car doesn't have cats. Excuse my ignorance, I know almost next to nothing about tuning... So is the car basically at it's optimal running condition tune-wise? I'm guessing it wouldn't make sense to get it re-tuned for more power and/or fuel economy right? The car is my DD so I'll glady sacrifice some power and fuel economy for reliability.
As for DFCO... from my understanding, it happens when letting off the throttle while decelerating, but not shifting into neutral in order to avoid using idle fuel... if that's the case, I'm pretty concious about not coasting in neutral and just leaving it in gear instead.
One more thing, is it true that the car put down 375whp if you can somehow remember the number? You wouldn't happen to have a copy of the dynosheet would you?
I appreciate the reply, thanks a lot.