Fuelish Question Wednesday, 05-Jul-2000 12:38:26 206.144.186.161 writes: To get ready for the 4th I retorqued the heads, replaced the plugs, and filled her up with race fuel. Keep in mind teh plugs I pulled out were beautiful golden brown. So I take it out, stage it, hit the 2 step and let it rip. It takes off, touches the wheelie bars, then at 5,500. rpms it falls flat on its face? I drive it back to my garage and pull a plug and it still looks brand new, no different from one in the box! So my question is does race fuel make your car run leaner? I have an 82 by 94 with 9.2 to 1 CR. Thanks Damon

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Re: Race fuel may be more viscous......requiring a larger jet Wednesday, 05-Jul-2000 13:12:31 205.188.199.145 writes: Switching from street fuel to race fuel usually requires a rejet. Damon, I don't think your motor requires race fuel, as we didn't set your compression that high this time around, and you have a generous amount of cam overlap. Plus, your buggy only weighs 1K, right? Drain the race fuel, and go back to premium unleaded, and try again. Did you solve your jetting problems. I have found stumbles at 3000-3500 when using a too large idle with a large main. But....start with the idle jet first. Does the car hit hard off idle? Or does it hesitate, and stumble and snap up through carbs? I would think 65 idles with 120 air caps would work great. Then run the idles up to 3500 (driving it), does it run clean? Try cruising at 3000-3500, does it hunt around, or does it run clean? If it hunts, but runs better off idle than it did with one size smaller idle jets, then look at a smaller main. I found this hunting when the main was too big, and it "overlapped" the idle jet at these rpms. Top end? Once you get the mains right....look at air correctors. A change of 3 steps of A/C jets is about the same as 1 step main in the upper end. Needle valves? Fuel supply? Does it do this in all 5 gears? help us help you.... Jim Ratto

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Ratto Man, here are some answers.. Wednesday, 05-Jul-2000 16:10:38 206.144.186.161 writes: With the unleaded 92 octane in ran strong from dead stop to 6,000. rpms. This was done with: 40 vents 110 air caps / 65 idles 160 mains / 190 airs 50 pump jets I thought my compression was border line race fuel? I think we were shooting for 9.2 and it ended up at 9.6, remember? I dont. Needle valves I dont know. I had lots of fuel. It runs good cruising at 3,000 rpms, no hunting around. Do you think it could be a balancing problem with "Ball Peen"? Thanks! Damon

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Re: Fuelish Question Wednesday, 05-Jul-2000 13:17:37 207.113.167.140 writes: Damon, you problem is not caused by the "race fuel" as higher octane gas actually burns "slower"(that is, it takes a higher temp to light off). This having basically the same effect as slightly richening the mixture, and/or slightly retarding timing. High octane gas will actually hurt power production it is not required, by high comp, excessive timiin, NOS, etc... iluvnos

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Re: Fuelish Question Wednesday, 05-Jul-2000 17:03:30 62.60.2.149 writes: Race fuel leaves a different fingerprint on a plug.Look to the base of the electrode it should be light grey. Your compression is on the borderline for race fuel.Use VP C12 and lean the motor out by re jetting. Good luck Ray Watkins

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Re:Bottom line with my SSB racer is that it lost MPH in back to back runs with a 1/2 tank of C-12 fuel....

Wednesday, 05-Jul-2000 17:57:33

209.179.228.254 writes:

My motor was 2332 (84x94),5.6 rod,FK78,8.7 to 1,

and abuch of other big stuff.

I would try it at the track and see. I drained the carbs and all to make sure it was running on the fuel . Have fun,

Mark H