Fuel and timing discussion....
Thread Starter
Le Mans Master
Joined: Oct 2001
Posts: 5,577
Likes: 3
From: Southern Maryland Maryland
Fuel and timing discussion....
Yesterday I was reading an article on fuel and it sparked some thought. Basically the article was about high octane fuels and how you can take advantage of the burn time by adding timing to produce more horsepower. The higher the octane the longer the burn time hence more lead in the spark. The more you lead the spark the more combustion of the already expanding gas. How much horsepower is available from going to higher octane fuels and adding more timing? Any rule of thumb?
Phillip :confused:
Phillip :confused:
Race Director
Joined: Sep 1999
Posts: 12,425
Likes: 907
From: CONCORD NC
Re: Fuel and timing discussion.... (Phil97SVT)
I asked the same thing back in the Winter, as our series has gone from 100 to 104 octane fuel. I was told it makes very little gain. I think the timing/octane is much more important with increasing compression ratio than simply for more timing.
I'll check over on the engineering tips forum for more info. http://www.eng-tips.com/
Dave
http://www.eng-tips.com/viewthread.c...SPID=71&page=1
to follow my thread
[Modified by davidfarmer, 1:08 PM 7/21/2003]
I'll check over on the engineering tips forum for more info. http://www.eng-tips.com/
Dave
http://www.eng-tips.com/viewthread.c...SPID=71&page=1
to follow my thread
[Modified by davidfarmer, 1:08 PM 7/21/2003]
Safety Car
Joined: Nov 1999
Posts: 3,891
Likes: 2
From: Houston, TX
Re: Fuel and timing discussion.... (Phil97SVT)
There will be virtually no difference in power what so ever. The only way it is going to help is by helping to keep detonation away. You lead the spark by the burn rate of the fuel you are tuning with plus some for plame propagation. If you fuel burns slower (not necessarily true with higher octane ratings), then you will need to lead the spark more. If you have it tuned for a quick burning fuel and put a slower burning fuel in it, then there is a HP gain tuning for the other. The HP should be the same as long as there is no detonation problems.
Good Luck,
Good Luck,
Melting Slicks
Joined: Feb 2001
Posts: 3,360
Likes: 1
From: DFW TX
Senior Member
Cruise-In III Veteran
Cruise-In IV Veteran
Re: Fuel and timing discussion.... (Chris@SpeedDemon)
Well it also depends on the fuel. Standard 104 unleaded burns good with 32-33 degrees of timing, but doesn't usually make much power than 93 octane at 28 degrees at the same compression ratio. Some oxygen3ated race fuel can pick you up 10-20HP. Where more power from race fuel really comes in is allowing you to run much higher compression ratios of the engine without detonation.
[Modified by Godspeed, 6:49 PM 7/21/2003]
[Modified by Godspeed, 6:49 PM 7/21/2003]
Premium Supporting Vendor
Joined: Oct 2001
Posts: 8,392
Likes: 572
From: Dallas Tx
St. Jude Vendor Donor '03-'04-'05-'06-'07-'08-'09-'10-'11
Re: Fuel and timing discussion.... (Godspeed)
ON the extreme end of fuels, elf fuels made a Motorcycle gas that cost $35per gallon but it made about 25 more hp in our race engines. That was outlawed in our series. Then we went to another brand that only cost $17per gal, and that added 18hp. that was outlawed also, and now they have a spec fuel that costs $7 per gal, and it works the same for everyone.
Just a note: With the two high powered fuels, we had to richen up the mixture 3 jet sizes, and retard the timing 4 to 6 degrees. Thats right, RETARD the timing. I guess when you put "Explosives" in your fuel, you will have to retard the timing. :D
But it made power, and burned the drivers eyes in the car behind you. But it had a "Sweet" smell. I loved it.
LG
