Fuel Survey

[cdignition]

Hi all, i am building a 500" stroker motor, Indy SR-1 Ported Heads, 12.5:1 compression. I am wondering what fuel mix may work well(what do you use?). I was thinking of mixing VP C12 50/50 with 93 Pump gas...I have been told this will support this motor to 7500 RPM. Thanks.

[BugEyedValiant]

Why not use Vp red. I am no expert, but why would you want to mix the 93 and c12? Another option around here is to use Union 76 fuel because it is only $2.85 a gallon and it is 108 octane and runs well in a 12.5 to 1 motor. I have always had better luck with running pure race fuel. I also run race fuel in my ATV, because when I had to tear it down, it was14 yrs old and the piston was clean with only the red dye in the intake port. I know that all of the motors that I have had with pump gas were DIRTY at the time of tear down. Besides, if you let it set for the winter, VP says that their fuel will not go stale as long as it is not left out in the open.

[MoparBilly G]

CD,
I agree with Bug Eyed, I have much better luck with straight race fuel!
Also, you have a substantial investment in that engine, and the quickest thing that will kill it is detonation!!!!
It's better to be safe than sorry, so C-12 would be my starting point:
Here's something I've learned, IF A CAR GOES QUICKER ON A HIGHER OCTANE FUEL...it was detonating on the lower octane fuel you were using before!!!! The higher octane burns slower so the car should run the same or slower if you run a higher octane than it needs.
If you are running a stock block then you must avoid Detonation, so don't get cheap on fuel, and keep the timing conservative!!!

[340king]

I pretty much agree with the previous posts. We use VP C-12 exclusively. One day we ran out because we went all the way to the finals. Two rounds from the end, we ran out of C-12. We then went and bought the house brand stuff at the track. It was supposed to be the "same". We went from running 11.85's to 12.17 on the last pass. The engine started running hotter and we were having a tougher time cooling it between rounds.

The performance advantage with some fuels could be the additive package and the chemical potential engergy of the burning of that additive package. Each blend has a specific amount of potential energy available. Several factors come into play like the compression ratio desired, RPM range and fuel type(gas/methanol). VP recommends matching your fuel to both the compression ratio and the RPM range. The vapor pressure required to flash over at 6,000 rpm is different than the vapor pressure required to flash at 8,000 rpm. Matching these can optimize the efficiency of the engine/fuel combination. In your case I think C-12 is pretty well suited.

[Beeracuda]

The density altitude you are running at also makes a difference. The track we run at is 3100' above sea level and in the summer we have seen the DA above 7000'! According to VP, we could run C12 most of the year but at the high density altitudes it would be marginal. So we run C14 year round....better safe than sorry.

Monty

[MOPARMANJAMES]

I agree with Beeracuda, this stuff all cost the same at my track, except the 93, so why not get the best when you have that kind of compression? Hey CD, How's the engine coming? I just built a similar combo for a friend and he's afraid to run it now!! He's got about 10 grand into it and it just sit's there in the corner.

Here's the combo

440block, .030 wiseco shelf pistons from ICH
4.25" crank, stock length rods
Fully ported SR's
Crane roller 264 @ .050, .650 lift( He already had it so we used it)
Indy intake with 1150 dominator
14:1, 505ci of stump pulling power!

I couldn't afford an engine like this so I was looking forward to seeing it run but now he's sold his 69 Charger and he's probably going to sell this engine too!