100 octane in a DII?

[Jupiter Rover]

would it be a bad idea to put in some 100 octane fuel in my DII?

they have a sunoco near me at a race track that has 100 octane fuel that is street legal.

i wanted to see how peppy it made my ride..

 

[braves6117]

A quote from you on the cat removal thread ""try it and tell us..."

Do it!

 

[Jupiter Rover]

haha.. maybe i'll just have to

 

[stolenheron]

haha i was thinking about an octane booster today when i was pouring in hte seafoam. i have a feeling its not the best idea to run a whole tank of that stuff. now mixing in a few gallons may not be a bad idea. but i could be wrong. do it and tell me how it goes haha.. btw, keep a fire extinguisher handy.

 

[Big Papa]

Eh, dunno. I wouldn't think it would do any harm. Try it and let us know. atriot:

 

[alex]

I doubt you will see any improvement at all. These engines aren't built to run on race gas.

 

[jeffro0502]

If it doesn't work take it up a notch....JP4!

 

[MUSKYMAN]

100 motor octane rated fuel has less stored energy then 87.

to raise the octane they add burn inhibitors that makes the fuel less volitile.

if the car does not have enough programmed spark advance to need the higher octane there is no reason to run the more expensive fuel.

so whats the plan gonna run the thing at indy two weeks from now?

this is a dumb idea...

 

[traveltoad]

this is a dumb idea...

Aww... you're no fun...

 

[stolenheron]

i would die laughing if pete started running 12s in the quarter because of this fuel

(which is completely impossible)

 

[Jupiter Rover]

it was just a question chill musky haha.. so Your telling me we should use 87 octane instead of 93? .... hmm.... i'd rather not.

 

[allenmj]

doesn't most racing fuel use lead? that would tell me no.


""try it and tell us..."

 

[Jupiter Rover]

sunoco:

Overview

Sunoco 260 GT? 100, which has the highest octane rating of any street legal fuel, is now available at selected retail locations.

Sunoco 260 GT 100 is designed for high performance street cars, muscle cars, classics, street rods, motorcycles, karts and marine applications. Sunoco 260 GT 100 contains no metallic compounds to harm catalytic converters or oxygen sensors. It contains a comprehensive additive package for greater engine protection and reduced fuel system deposits. Sunoco 260 GT 100 is also compatible with virtually all two-stroke synthetic and mineral based motor oils.

Sunoco 260 GT 100 Unleaded is available at selected locations throughout the
U.S. In certain areas, Sunoco 260 GT 100 Unleaded is available under the CAM2 GTTM 100 label.

 

[ptschram]

In the early 80s, I ran 100/110LL AVGAS in my race car. All was well until I was caught putting AVGAS into a vehicle with license plates on it!

The only problem I ever had was with the FBO disallowing me from pumping directly into the vehicle fuel tank. After I got caught, I had to fill a five gallon can, pay for it and pour it into the car and refill the can.

It will not harm anything and in spite of what Thom says, there might be a very slight benefit as the EMS would not need to retard the timing as there is likely never a chance of pre-ignition when using such fuels.

The only downside I can think of is the ricockulous price.

 

[R_Lefebvre]

100 motor octane rated fuel has less stored energy then 87.

to raise the octane they add burn inhibitors that makes the fuel less volitile.

if the car does not have enough programmed spark advance to need the higher octane there is no reason to run the more expensive fuel.

so whats the plan gonna run the thing at indy two weeks from now?

this is a dumb idea...

Well, I think it's worth a shot. We don't know how much advance the computer will allow. It's possible it will advance timing even further than it does with 91, leading to increased efficiency.

It's a bit of a long shot, but if somebody else is willing to try it on their dime and report back... it's an interesting experiment if nothing else.

Also, if we could find the GTX which is not oxygenated (pre burned) then it could help even more.

btw, keep a fire extinguisher handy.

Is this a joke?

 

[bmohan55]

I've gone from 15 mpg to 16.2 mpg by upgrading from 91 to 93 octane...on highway only

 

[R_Lefebvre]

Yeah, it's unfortunate that 91 is pretty much the best we can do in Canada. Sunoco has 94, but it's got 10% Ethanol which negates the benefit compared to 91 I can get that isn't "preburned".

 

[MUSKYMAN]

yes guys in a DII you will get better mileage using higher octane fuel...but only to a point.

and that point is were the base map spark advance is capped...and it is capped. automakers cap it so the ECU does not try to advance the spark to the point of engine damage.

dont forget they are the ones on the hook for warantee issues and issues they would have if the spark was always looking to adavance more and more. the reccomended fuel is selected based on the max spark advance for the engine design.

thinking 100 octane will get you anything is just crazy thinking...I am sure that fuels not cheap these days.

 

[Jupiter Rover]

thinking 100 octane will get you anything is just crazy thinking...I am sure that fuels not cheap these days.

91 octane where i live in florida is $4.00.. so 100.. is idk around $6 maybe haha. 6 x 25 = 150..

big gas bill!!

 

[R_Lefebvre]

yes guys in a DII you will get better mileage using higher octane fuel...but only to a point.

and that point is were the base map spark advance is capped...and it is capped. automakers cap it so the ECU does not try to advance the spark to the point of engine damage.

dont forget they are the ones on the hook for warantee issues and issues they would have if the spark was always looking to adavance more and more. the reccomended fuel is selected based on the max spark advance for the engine design.

thinking 100 octane will get you anything is just crazy thinking...I am sure that fuels not cheap these days.

'To a point' = Mean Best Timing

MBT is the timing advance at which the engine achieves it's highest output. MBT is often higher than the point when detonation occurs, even on 91. The engine computer will always try to advance the timing to MBT, until it detects detonation from the knock sensor.

What we don't know is how high the MBT is on these. We'd only find out by testing. If you use 100 octane, it will prevent detonation, allowing the engine to run up to MBT.

I don't know why you suggest engine damage from the timing being too far advanced. That's the point. If you run 100 octane, the timing should advance to MBT or the knock limit, whichever is lower.