Yeah, the head room isn't much after 30. I'd use the least ethanol required to get clean pulls. That way you have headroom for fueling for longer pulls.
7
Unitronic IS38 Boost Level?
- Thread starter mr wrong
- Start date
Yeah, the head room isn't much after 30. I'd use the least ethanol required to get clean pulls. That way you have headroom for fueling for longer pulls.
tigeo
Autocross Champion
- Location
- Richmond, VA area
Exactly - 20%-ish seems to be perfect to get the max timing advance without fuel delivery issues.
tigeo
Autocross Champion
- Location
- Richmond, VA area
Here's a log I just did - it's about 90 out here, 52% humidity. ~250msl, 30.09 baro pressure. Just a drive around my "loop" with a third gear pull from ~2K to redline in there about in the middle. 2.5 gal of E81 + balance 93 (E10). Smooth as butta! Also interesting to see the temp delta IAT-outside (I have that as a data point I did in the .cvs before import) so ~15 delta isn't bad at these temps. I've seen less than 10 when it's cooler out. Enjoy.
https://datazap.me/u/karstgeo72/08092021gsw?log=0&data=6
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That turbo is barely breaking a sweet..hehe.
tigeo
Autocross Champion
- Location
- Richmond, VA area
Yeah, I've seen about 22 tops out of it so lots of room but you do get a nice flat boost profile without the dropoff out on the end like you do with the 20. This thing is ripe to stack with a JB4...
mr wrong
Drag Racing Champion
- Location
- Franklin TN
Just wanted to drop back in and say thanks for the E85 lessons.
OK.. Dumb question here, but aren't winter blend fuels basically E15/20? Am I correct in assuming that the E85/xx is the percentage of ethanol added to gasoline?
tigeo
Autocross Champion
- Location
- Richmond, VA area
Yes that is correct, E10 = 10% ethanol. The issue is other additives with winter blends (as I understand it mind you) and this issue of "shitty winter fuel blends" seems pretty common to folks with tuned cars.
From gas buddy:
Winter Gasoline In winter, gasoline blends have a higher Reid vapor pressure, meaning they evaporate more easily and allow gasoline to ignite more easily to start your car in cold temperatures. This blend is cheaper to produce, which results in lower gas prices at the pumps from late September through late April.
Yup. That's what I was getting at. Up the boost and you basically have the same timing curve I use for the E30 tune on my car.
tigeo
Autocross Champion
- Location
- Richmond, VA area
A few other bits I've pulled together on the Uni tune from some recent logging on higher quality summer 93 here in VA - to be honest, I never did much in the summer/warmer mos. b/c it's not condusive performance but here you go:
Cold/cool weather:
More boost, up to ~21
On 93, see more timing correction, max timing ~8 and ocasional limp mode/misfires/etc. Timing correction up to -6.
On E~20, see no timing correction, max timing ~14
Temp diff IAT-ambient less than 10
Hot/warm weather:
Less boost, up to ~20
On 93, see minor timing correction, max timing ~13. Timing correction up to -1.5.
On E~20, see no timing correction, max timing ~14
Temp diff IAT-ambient 15-20
It's weird that cold weather would result in more boost. Normally, colder weather would result in less boost on a torque based tuned (which I assume the uni is). Do you mean the curve is different?
I don't think there is any doubt that the timing table is set for a peak of 14 degrees of advance since both your ethanol pulls stop at 14 degrees.
Were either pull more than 100 degrees IAT? That's about when the ECU starts pulling timing for IAT.
Can you flash the Unitronic 91 octane map in the winter for free?
I don't think there is any doubt that the timing table is set for a peak of 14 degrees of advance since both your ethanol pulls stop at 14 degrees.
Were either pull more than 100 degrees IAT? That's about when the ECU starts pulling timing for IAT.
Can you flash the Unitronic 91 octane map in the winter for free?
tigeo
Autocross Champion
- Location
- Richmond, VA area
Yes, the IATs for the recent 93 runs are above 100 deg. I could run a modified tune from Uni in the winter but running a few gal of E works so well I'm not going to bother. I was just talking about peak boost numbers - the curves look the same to me.
So the two logs are from two slightly different tunes? Hopefully you have E easily accessible so it's not a big deal. I just don't like the idea that the car doesn't run right on the fuel it was "tuned" for.
tigeo
Autocross Champion
- Location
- Richmond, VA area
No, same tune the whole time - it just shows that our winter fuel here causes some issues as the current 93 runs perfectly. I could get them to give me a lower octane tune for winter for sure as we have talked about it, it's just easier to run a few gal of E if I want peak performance.
Yea, if filling with some E is not a big deal then it will get you the best results in terms of performance. I suppose you could get a 5 gallon container for E for home and just top off a gallon each tank also. The refuel amount dash display is accurate enough. You could just fill 1 gallon under, then pour 1 gallon of E in to the tank at home.
tigeo
Autocross Champion
- Location
- Richmond, VA area
I keep 2 5-gal jugs at home and that's what I do - just splash it in as needed. I fill up to ~2 gal under then top off typically. We have E a few places within 30 min so getting 10 gal once in a while isn't any drama.