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Author Topic:   Fuel reccomendation?
Dirt Forum Champ
Total posts: 968
posted April 17, 2005 12:25 PM  
406 flat top with the pistons .012 in the hole, Vortec heads from Wheeler, 1.94/1.6, soild .500 lift cam, 6800 rpm
Should I run race gas or can I run high test?

Dirt Full Roller

Total posts: 69
posted April 17, 2005 12:53 PM  
Ask around, I think the race gas usually needs decent compression to get it to burn in the cylinder and not in the exhaust pipe (header glow). I haven't ran the combo that you desribe but tried 110 avgas with flattops and double humps years ago. After jetting down a little the 93 octane seemed to burn better for me. You might consider a half and half mix if you are on the fence.

Dirt Freak

Total posts: 402
posted April 17, 2005 01:53 PM  
A 406 with flat tops and vortecs should be pushing 11-1. My self I would just run straight race gas to avoid problems.

Dirt Forum Champ
Total posts: 5390
posted April 17, 2005 03:07 PM  
60-40 mix of 110 and 93 would be advisable. You should be right around 11:1 and 104ish octane would me enough to avoid detonation. The least amount of octane required to keep it from detonating will make the most power. With the Vortecs, a 50-50 or 40-60 mix might even work with the better chamber design.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted April 17, 2005 08:08 PM  
I agree with Raz. We have had a motor that was around 12.5:1 and ran 93 octane but the heads were worked HARD and the piston and chambers were mirrors to remove hot spots. We are now running a crate motor and 93 seems on the verge when it starts getting warm. We dyno'd it and can get away with 1gal of 110 mixed with 4 gals of 93 Amacco supreme and did not see anything on the dyno where 110 dropped about 8-10HP

Dirt Forum Champ
Total posts: 968
posted April 18, 2005 01:46 PM  

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