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Author Topic:   Racing Fuel
Dirt Maniac

Total posts: 174
posted April 18, 2002 03:27 PM
Hey guys I read somewhere that if you don't run alot of compression your motor would actually run better by mixing premium pump gas into the racing fuel (we run Unocal). I've seen guys actually go slower by trying extremely high octane race fuel, like 116, because the motor burned it too slow, I guess. Now, here's the question; with 64 cc heads with about .038 quench, four valve relief flat tops, stock rods, 350 about 6400 rpm, do you think I would benefit from from adding pump gas to my racing fuel? What carb adjustments do you think I would have to make to the 4412? I think the Unocal is about 108 octane. I'm going to search for a calculator in the tool box up there to estimate my compression ratio. Thanks.

redneck racing
Dirt Freak

Total posts: 276
posted April 18, 2002 05:30 PM
Rangerover i have run the Unocal 108 octane my motor is a 355 10-1 compression last year i ran the Cheveron 92 octane in it with a bottle of 104 octane boost and couldnt tell the the difference the car seemed to have the same amount of power to it and my fuel bill was lower it also ran great on 92 octane alone so i hope this helps. Eddie

Dirt Freak

Total posts: 237
posted April 19, 2002 07:57 AM
Last year I ran a 10:1 CR 355 and mixed fuel all year. 3 gallons of CAM2 (110 oct) with 2 gallons of 92 octane pump gas. Not a problem all year, and saved me some money too.

This year I'm up over 11:1, so I'm sticking with straight CAM2.

Dirt Maniac

Total posts: 174
posted April 19, 2002 10:17 AM
It looks like I'm running about 10:1 cr also. My main concern is that if my jetting and ignition advance (34-36) settings are showing good in the spark plugs and I drop the octane of the fuel by mixing pump gas, what changes or adjustments could I expect to need to make?

We have been running the good racing fuel for the safety of its detonation suppression qualities, and maybe as custom from our old sportsman days when we ran bad *ss motors. I'm thinking that if we don't need that good of gas and it may even be costing a couple of horses, then why not save some cash and possibly run better.

I was just thinking; what about mixing av-gas with the Unocal?

Dirt Freak

Total posts: 330
posted April 19, 2002 12:49 PM
From what I know, which isnt much. If your timing is going to be 34-36 you'll need the higher octane or you'll burn your pistons. Happened to my brother when he mixed premium with racing gas. We didnt think about it.

Smith Racing Team

Dirt Freak

Total posts: 349
posted April 19, 2002 04:54 PM
the avgas is leaded, and I don't really believe you will gain anything by mixing. I believe the higher commpression engines are the only ones that really benifit from high octane gas. (13 and 14 to 1 engines.) I think if you mix racing fuel and pump gas you stretch you dollar and maintain a octane rating that is a little higher and helps detonation and burn.

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