Doing my first DE next weekend and wondering if I should alter the tune in my STU car? Currently tuned on 93 octane for whatever max boost the stock hardware can give me and a timing curve that supports zero knock. AFR’s are mid 11’s through mid rev range, droping to high 10’s by 7500rpm.

This works well for a few highway pulls and a 60 sec autocross run, but not sure what to expect with a 20 min WOT session.

 

Easiest solution is to switch to 100 Octane for the event for extra safety margin.

My pump-gas STU tune is too aggressive for long straights in 4th and 5th gear. You can't (shouldn't) be testing those long 5th gear pulls on the street, so you might get surprise knock in the higher gears on track. Better to dial back timing a bit and/or add 100 Octane.

 

Great advice, I also lower the boost for my track days as you will be at full boost for a majority of the session, better to lower power and learn how to make the car faster with your driving.

George

 

On surface your AFRs sound like they would work well. Reality is though that full on 20min track sessions put a lot more hit and strain through the system than auto cross or highway pulls so as others have said probably worth dialing back the timing and boost.

 

 

It's all about temperature management then. So the less the boost/timing the better. The richer the better. Obv taking into consideration the rest of your parts and the car running well. Most people run 11.7ish max in 4th and some mix of race gas for that extra knock protection. When starting out I used to mix leaded with 93 and that was "fine" but ultimately isn't ideal. Better to use straight 100 unleaded based on availability. Currently it's running about 12 bucks a gallon lol.

 

Boost will be fine. I would just richen it up. 10.8-11.0 all the way through the RPM's. If the car is tuned properly timing should be fine. But some tuners like to go HAM, so it's hard to say. My track tunes all I have to do is lower boost for heat management. Nothing else gets changed..

Arbitrarily lowering timing is not always the answer. This can raise EGT's and do more harm than good. generally for track use, AFR and boost are what gets changed, timing really doesn't change, or you actually end up running more timing because boost is lower. But you won't be changing boost. It would be best to discuss this with your tuner as they know how the car is tuned. I fhtey went agro knowing the car only sees short spurts and can handle an extra degree or two due to never seeing much heat soak, they may want to pull timing. But again, it depends on how they tuned it..

 

I'm not overly concerned with the power the car makes. Its my first DE ever and i'll probably be leaning towards the cautious side of things.

STU Evo X has minimal mods... intake and exhaust with high-flow cat. Car was tuned for zero knock and runs great on a 60 sec autocross course. I tuned it myself and if I had to bench race.... makes 320ish whp and slightly more torque. But, I've never monitored EGT's. (is that even a thing anymore?)

Plan as of now is to lower the boost a few psi through the midrange and run a few gallons of 100octane.

 

Your first track day ever? STU setup Evo with oem boost control?

I wouldn't even touch the tune. Put a couple gallons of 100oct in if it makes you feel better.

There are going to be a hundred other things you will be concentrating on your first day.

 

I never touched the engine or tuning setup the previous owner had done by Vishnu years ago until after I had heat and knock issues at Laguna.

After Laguna we pulled back the timing and boost and she went from 330whp to 290. Since then I've been running a few gallons of 100 octane in each tank and I haven't had a single knock or heat issue at the 3 track days we have done since.

 

I have noticed that my tune went rich during loong full throttle applications on the track. I think it has to do with tunning my car with lean spool enabled.. anyway, I never changed my tune between road and track..

 

Bumping this one...
After logging my car and realizing it wasn't tuned properly at all I flashed a stock map only to discover that it knocked plenty on 93 octane and stock boost. Since then I've been tinkering with it myself just trying to come up with the safest possible tune for HPDE.
How strict are you guys with your track tunes? I've been aiming for 11.5-11.3 afr until nearly 4000rpm and then having it go to 10.8-11 and basically just pulling a degree of timing wherever it knocks after numerous pulls in 85-90 degree weather (the turbo side of my intercooler was too hot to leave my fingers on by the time I was done). In doing this it has improved plenty but I still get a series of knock here and there, mainly in the mid range. At what point should you avoid reducing timing lest you raise egts too high? I'm running on 93 at 20psi tapering to just under 17 on an evo 8 with 3" exhaust and hks cams. If some people could post their timing tables that would be greatly appreciated.

 

AFR should go from 12.0 to mid-uppers 10's as boost comes and reaches peak. Seems like you're getting the fuel in a bit late.

0* of timing around 3500-4000 and smoothly ramping up to 11-12* by 8k should be a good starting point.

 

Timing depends a lot on your mods, so I'd be cautious copying others' maps. That being said, you can find a lot of examples (and dissent) in this thread:

https://www.evolutionm.net/forums/ec...ming-maps.html

 

I just let it knock. Jk

I run E85 so it's practically impossible to knock at lower power levels unless something is WAY off.