PART 3: AV gas in a turbo 2 stroke

[Octanee]

Ive always heard that 100ll wasnt the best for high rpm more than any other negative about it.

Ive never ran it but going to start working with it this winter, theres to many turbo sleds running it over the years that I can lean towards the side of "best fuel for the money"

Ive always ran 110 sunoco and it has always been consistent and readily available for me but the price has almost doubled (which I dont mind paying if its what works)

I can get 100ll as easily as sunoco/VP and at less than half the price im definitely going to try some. With the whole RPM thing running it in a boosted apex (over 10K rpm) was always my concern.

Theres also some places close to me advertising ethanol free 93 but its over $6.00 per gallon! over $10 for sunoco (used to pay $6.50) and $4.20 for 100ll. With crappy pump fuel getting in the mid 3.00's Im ready to start running av gas!

I usually run low boost 12 psi 5-7K feet with a head shim 9.3:1 which has proven to me to be safe with 100% pump fuel but no DET sensor I usually put in about 2 gallons of 110 for some peace of mind. I can attest that when I run 17-18 psi with straight 110 when the sled is cold it definitely starts slightly harder and has slightly less on off throttle response until boost is built.

I wouldn't think or take concern to it about a higher rpm engine. It's a fuel that's ignited by spark. I had an apex with the head shim, When I first got it I had run av gas through it with pump gas mixed in, then I ran out of av and just ran the pump gas, I can get 94 so it worked fine, Ran it at 18# some days and never seen a det code or had an issue.

 

[fredw]

Ran suncor many years ago and ran well, but costly and hard to get, switched to av gas and get it at local airport, very predictable, just got told to increase burn rate of av to make it close to race gas by turning up timing one degree, just giving it a try for first time this weekend, hoping to see a difference on lower rpm, can tell a difference at idle how it’s sounding

 

[black z]

~2 gallons of VP 110 per tank with the rest 91 non oxy. 14 pro 7 psi silber setup, has worked great.

 

[JJ_0909]

One thing I don't see mentioned here is the supposed "leaner burn" of 100LL. This being due to the fuel being less energy dense. Anyone care to comment. I know way too many people (myself included) with a ton of success with the fuel, so I'm not sure how much to note this...but the facts suggest it would be a bit less energy dense...

 

[orange2]

Here's my experience, bighorns, 16 axys assault, silber turbo 5lb spring, started with 4 gallons of e50, yes e50, filled with 91 ran great on boost, next day pit in another gallon of e50 and 5 gallons 91, much better off boost throttle response no codes ever and probably could have just ran 91. So back in Iowa, 3 lb spring, 50/50 e50 and 91 runs like a scalded dog, and I'm thinking just a couple gallons of e50 would be sufficient. Just my experience, run e 85 in a procharged Vette so I know how boost likes corn fuel. I'm sure at higher boost I'd run out of injector here in Iowa but at 3lbs it's fast and quick enough lol

 

[black z]

One thing I don't see mentioned here is the supposed "leaner burn" of 100LL. This being due to the fuel being less energy dense. Anyone care to comment. I know way too many people (myself included) with a ton of success with the fuel, so I'm not sure how much to note this...but the facts suggest it would be a bit less energy dense...

The energy density is negligible, in my opinion. From what I gather, 100LL has 112,500 BTUs per gallon, while 91 pump gas has ~115,000 BTUs, slightly less if the blend has 10% ethanol. Theoretically the 100LL should have a slightly richer stoichiometric air:fuel ratio, but with the increased octane, detonation should not be a problem. If the fuel works well, stick with it.

 

[black z]

Here's my experience, bighorns, 16 axys assault, silber turbo 5lb spring, started with 4 gallons of e50, yes e50, filled with 91 ran great on boost, next day pit in another gallon of e50 and 5 gallons 91, much better off boost throttle response no codes ever and probably could have just ran 91. So back in Iowa, 3 lb spring, 50/50 e50 and 91 runs like a scalded dog, and I'm thinking just a couple gallons of e50 would be sufficient. Just my experience, run e 85 in a procharged Vette so I know how boost likes corn fuel. I'm sure at higher boost I'd run out of injector here in Iowa but at 3lbs it's fast and quick enough lol

I would be careful with the E50...the stoichiometric air:fuel ratio is considerably more rich than pump gas. The electronics may be able to compensate, but I'm not sure. Better off with 100LL or VP 110 at a lower mixture.

 

[orange2]

It has to be compensating or I would of had issues by now.