Hey guys,
I just did some advanced tuning on my SR8, and my tuner gave me some eye-opening data on the differences between gasolines. No wonder all the top race teams partner with petroleum companies!
Anyway, what kind of gas are you guys running in your SR8s?
Not a SR8, but half!
Sunoco 260GT, unleaded 105R/95M octane.
For my SR3 I always use 100 octain Racing fuel. Usually VP Racing fuel. SR8’s use the same.
Charley
We have a local place that sells it at the pumps - 100 octane and I believe it's VP. They also sell VP by the 5 gallon jug and I need to compare pricing between a jug and the pump.
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming 'WOW-What a Ride!'"
That's all I ever checked: octane and whether or not it's leaded.
The Sunoco 260GT (I have 150 liters) is oxygenated and contains 13% ethanol, with a stoichiometric ratio of 13.7. The VP CT12 (sold at Sebring Int'l Raceway) has neither oxygen or ethanol, and has a stoich of 14.9. VP MS103, of which I have 58 liters, is oxygenated, but no ethanol, and has a stoich of 14.4.
And then there's molar mass and specific gravity, too! I didn't know the tuning would be this complicated!
All of those are "unleaded race gas" which meet the SR3/SR8's requirements, but they make a significant difference in tuning.
I like the added oxygen, because we can’t get enough thru the intake at this altitude.
With your new ecu, you should be able to set a target AFR, and let the closed loop use the O2 sensor to make the fine adjustments.
Graeme, yes, that's right. Closed loop will put the car in perfect lambda. I'm running dual sensors too, so any bank to bank differences are handled as well (which is a real problem... the cable/return spring linkage between banks requires constant adjustment).
What was surprising to me is that lambda 1.0 is different for different racing gasoline. I didn't expect to have to know the fine details of the gasoline currently in the tank. 🙂
John, I was surprised to hear the differences in the fuel also. I thought that the would have been closer.
For those running VP fuels in an SR3, what are you running? MS103 seems like overkill. Does anyone run MS93, MS100, or VP MOTO?
Is anybody running 100LL Av gas? Is this okay or even advisable?
@GraemeD Where are you sourcing your fuel locally? You ever buy the fuel at HPR? I try to always bring mine with me.
Hill petroleum, Arvada
Sunoco 260 same as HPR but cheaper.
Hill petroleum, Arvada
Sunoco 260 same as HPR but cheaper.
After a quick search, I found Sunoco 260 about 15 minutes from my house up North. About $8/gallon up here.
@tommymills, 100LL is formulated to burn best at higher altitudes and lower RPMs 1500-3000.
Also, 100LL is “low lead” not unleaded.
There is so much lead, that at 100 flight hr inspection, you have to dig the lead deposits out of the spark plugs.
