AV fuel or race fuel??

bachey · Oct 17, 2009

Just picked up an 07 phazer with an mpi supercharger and the website says 50/50 mix of premium and 110 race fuel. Could 110 AV fuel be used instead? I heard that AV fuel is drier But that shouldn't matter as much with a 4 stroke. I live very close to a small airport so the AV fuel would be easy to obtain. Any advice would be appreciated. (I'm only running 10 pounds of boost)

pylon · Oct 17, 2009

ive used 100 LL im my turbo nytro for 5000 km at 17 #s with no issues at all for 2 seasons now . i did pull my oil tank off to get powder coated and noticed a bunch of grey crap around the intake screen . I think its lead thats worked its way past the rings and into the oil over the last couple years .

thinksnow · Oct 17, 2009

I run straight 100LL in my turbo RX-1 @ 12#. Been running it that way for three years and so far so good.

BCAlpinejunkie · Oct 18, 2009

Ditto.

17lb MCX Apex.
Nothing but 100LL .
100LL is 105 octane.
Lead acts as a lubricant, boosts octane.
Keep a spare o2 sensor, just in case.

Twostroke · Oct 18, 2009

bachey said:
Just picked up an 07 phazer with an mpi supercharger and the website says 50/50 mix of premium and 110 race fuel. Could 110 AV fuel be used instead? I heard that AV fuel is drier But that shouldn't matter as much with a 4 stroke. I live very close to a small airport so the AV fuel would be easy to obtain. Any advice would be appreciated. (I'm only running 10 pounds of boost)

AV fuel is 100 Low Lead, not 110 oct.

I run it 50/50, good fuel.

tmbl52 · Oct 25, 2009

I run 100ll av with a little klotz upper cyl lubricant with no troubles.

4bangrboost · Oct 25, 2009

i had a MPI apex on 10 pounds of boost. yeah they say run 50/50. its really not needed at 10 pounds, even at stock compression. i ran my apex three seasons on 10 pounds with nothin but pump fuel. at 7000+ feet in the deepest of snow i must add. but if you want to be extra safe i would just throw in a gallon of race fuel

P.S. i never did take the engine out of my sled for any reason, headshim or repares

johnny be bad · Oct 25, 2009

just run a little 2 stroke oil in the gas, thats what i was told to do. seems to work fine.

BCAlpinejunkie · Oct 25, 2009

johnny be bad said:
just run a little 2 stroke oil in the gas, thats what i was told to do. seems to work fine.

Sounds like a GREAT idea.
100ll and a splash of synthetic:beer;:beer;:beer;

powdermuncher · Oct 26, 2009

Do not mix race or av gas for the little Phazer---they need all the help they can get to stay together under boost. Straight Av would be my way--I have run my TRX on it for 3 seasons with up to 18 pounds of boost 2 head-gaskets all else stock.
Our dealer is just rebuilding a supercharged Phazer and over the last few seasons everyone with a turbo Phazer did blow up--so be careful and do not crank up the boost. Good luck.

Wheel House Motorsports · Oct 26, 2009

yeah ^^^ the phazers DONT like boost quite the same as the other yami motors, if you push the limits of your octane that thing will die a quick death.

but 100ll would be perfect for what your doing, and running 200:1 or 250:1 something like that mixed 2 stroke oil in the gas it seems to help a little, helps engine life.. at least it seems like it and its cheap insurance.

tranquillicer · Oct 26, 2009

Phazer

My understanding of octane in all boosted sleds is that a higher level prevents or reduces the threat of detonation which would eventually cause failure of rods or brg. cap bolts. Is the problem with the Phazer engine failures a result of detonation or simply that they are not really able to handle the stress of doubling the hp output?
I was told by a turbo builder that he personally would never turbo a Phazer or build a system for one because they are not a good engine for boost. That being the case, I definitely would not cut corners on the fuel and would go easy on the boost. Guess the SC does not allow for control over boost level right. Bet thats a fun sled with 150hp though.

hottshot · Oct 28, 2009

Don't forget the LL in 100LL is for lube of valves so you don't need the xtra all you are doing is further die-lootin the fuel :face-icon-small-hap

Sleds R Fun · Oct 28, 2009

100ll

I've been running 100LL up to 18lbs. The only concern I have with LL is it's very dry. I'm starting to think it's hard on seals, valve seats and carbing up the valves, not sure if adding some 2 stroke oil will help. Maybe c16 and supreme pump gas mixed 50/50 is a better choice.

ikold · Oct 28, 2009

100ll

100LL is specifically designed to a. stay dry (keep water out of the fuel) b. prevent detonation at altitude. Its a great lower cost fuel when compared to race gas plus its actual octane number is like 104-107.
Should work well with boosted motors. The 114 should be even better but not necessary unless running large boost numbers.

EZmoney · Oct 29, 2009

Ive always run 100ll for up to 16 psi and no problems at 5500ft. although any thing over that i would run atleast C12 its just not worth the risk imo. With your phazer i would say your more than safe at 10psi and would not worry at the least

letsgetrad · Oct 29, 2009

I put 3000 km's on my phazer before i sold it last year, the motor was still going strong with 17 lbs of boost for the last 1000km's i rode it. had two intercoolers on it and ran straight pump gas(94 octane) with a head shim and timing control box. they are a blast but it seems like the phazer falls apart alot. (bushings and shocks)

wyomojo · Oct 30, 2009

Guess I'm the unlucky one on this thread. I ran straight 100LL at 10psi on an s/c Vector and ended up with 50% leakdown in all 3 holes in 300 miles. It was always rdden above 9,000 feet & the AFR's were good. I also had an s/c & water temp guage so I know it didn't get hot.

I had a reputable shop do the work & they blamed it on the av gas.

TurboKeith · Oct 30, 2009

15 psi on avgas with 10:1 compression has been working for me.

modsledr · Nov 1, 2009

wyomojo said:
Guess I'm the unlucky one on this thread. I ran straight 100LL at 10psi on an s/c Vector and ended up with 50% leakdown in all 3 holes in 300 miles. It was always rdden above 9,000 feet & the AFR's were good. I also had an s/c & water temp guage so I know it didn't get hot.

I had a reputable shop do the work & they blamed it on the av gas.

Just curious what you/they mean when they "blamed it on the av gas"?

What was being blamed on the av gas? What was the damage? Signs of detonation?

thx.

AV fuel or race fuel??

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