Gary Z

If you have a track-only car do you just tune at idle and WOT? I have always used highway data as a starting point after modifying my engine. Now that my car can no longer be street driven, I’m wondering how to tune for, say, bigger injectors, using only dragstrip data. I have HPTuners, a wideband, and I am reasonably familiar with the F-body PCM. I dislike dyno sessions. Any suggestions will be appreciated.

Dragman

Well I have my Vette pretty much tuned so when I go racing I usually only tune on VE table. To make sure my AFR is what I want it to be. I run SD open loop & use HP Tuner Pro. So all I fool with is fuel and maybe shift points. But have raced this thing for 5yrs.

white2001s10

iTrader: (4)

+1 OLSD tune
with lots of work on idle to keep the plugs clean under all temperature conditions.

darkhorizon

maf + open loop is still my favorite.

Gary Z

I experimented with speed density a while ago and decided it was too much trouble for normal driving. Now that I only need idle and WOT I may ditch the MAF and try again. I will be spraying a 150 dry shot and getting rid of the MAF will give me a better place to mount my nozzle. I am wondering why the responses so far have all mentioned open loop. I see no advantage to open loop at idle and with or without a MAF, WOT is always open loop.

racecar

I ran SD no maf closed loop for the last year and tuned on country highways so I could get my VE really dialed in. It drives good on the street, and runs great on the road race track. The PE is right for WOT, and it goes to closed loop for the corners at low throttle. Now I added a MAF and it is more friendly for street. Data from street tuning can be a good start for the track.
I would want to know the VE is correct before I go to open loop tune.

Gary Z

Hey, I didn’t expect genuine racecar tuning tips - I love this site. I agree street tuning is the best starting point but California does her best to make that difficult. Since I only care about idle and WOT tuning should be simple. I used to do my WOT tuning on a nearby freeway onramp. Now I just need to waste a few track passes.

turbolx

Tuning dedicated racecars properly is no different than tuning street cars properly. Even a 7-second drag racer needs more than just idle and WOT. What happens if you have to pedal it for traction? Is a stall OK then? What about a sluggish recovery from the temporary lift in throttle? ...catch my drift?

Regardless of whether you go SD, MAF or blended operation, the whole map needs attention to get the most out of the car. Whether you like it or not, the most consistent way to get this done is on a load bearing dyno.

Gary Z

turbolx - very good points - thanks.