Landracing Forum
Tech Information => Technical Discussion => Topic started by: Seldom Seen Slim on August 16, 2014, 10:22:52 AM
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I don't know of a specific place for this - so it'll go here.
I got this message today from Tim Kelly (Of LTA) and re-post it with his permission.
"I just received some advice form Kevin Cameron that I wanted to pass on to all of you. If you read cycle world you definitely know who Kevin is, and if you don’t, he is one of the true subject matter experts of all things racing technology, especially engines. He actually has a book that came out last year with the majority of his writings and it is fabulous for people like us. Anyway, please see his comments below about the race fuel.
All the best
Tim
(207) 227-1693 c
"Racers should know that fuel must be kept capped at all times to prevent evaporation and loss of its "front end" - the most volatile components such as iso-pentane, which are so necessary for cold-starting, snap throttle response, and top-end performance (when there is less time for fuel to evaporate before the spark comes). Lots of racers have found that when the drum gets down to 2/3 or so, they are having to put some "strange brass" in their fuel systems. A new drum restores performance like magic.
The end point is the temperature at which all the fuel is evaporated in a standard test apparatus. Pump gas often has an end point over 400 degrees (so the lamp oil jokes have a point), but race gas is usually around 300. Then there were the av-gas guys (I used to be one). All summer, the stuff runs great, but October Saturday nights under the lights? Weird mixture problems. Colder intake air can no longer evaporate that stuff 100%, so now your engine acts leaner than the gage says it should. It is - because now the least volatile components of the fuel are passing through the engine unevaporated and unburned.
I apologize for the lecturing.
KC"
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Can anybody translate this usage to normal english? It appears to be some sort of colloquialism but google does not come up with anything useful for the term in this context.
they are having to put some "strange brass" in their fuel systems.
Is this a product, or a phrase meaning you add a bit of fresh fuel to the old stale fuel, or a colloquial term for some common chemical like lacquer thinner?
( a friend of mine used to work in a small engine repair shop and they would use a slurp of common lacquer thinner as a starting fluid to get engines with stale fuel to start so they could check them out.)
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Ahh okay that would make sense -- thanks!
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It's not just oxygen. Light, heat, water, reaction with the container material and acids in the fuel all work over time to degrade the fuel. The clock is ticking from the moment it leaves the refiner. The fresh fuel at Bonneville isn't as fresh at World Finals and will certainly run the next year, but in the lawnmower.
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Any pitfalls to avoid in using up "not so fresh" race gas by running it in the tow rig, a lawn mower or other small engine, mixed for a chainsaw or weedwhacker etc?
Ed
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Lead in the gas may not be good for the tow rig
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We used to pour the unused gas 2 stroke mix in our cars before leaving the track. We got home without problems. Smelled good though.
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I asked Rick Gold about this as we have fuel in 15 gallon drums that are from 2011 and 2012. Ricks reply was the fuel is fine as long as the drums are tightly sealed.
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Speed Limit,
Thanks for the lead issue reminder, I had a brain fade on that.
taruck,
A little top end lube and 'skeeter spray eh? :-D
ack,
Thanks for passing along that info direct from the source.
Probably be handiest for me to run the odd gallon or two at season's end through the G 176 in the old Massey during snow removal.
Ed
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Yep, Rick and Ack mean that the fuel is still in its sealed ERC container... I talked about it before with Rick as well.
If you get it from Rick in his 5 gal can, it is good for a long time... until you open it, then it starts to age. But if you put 5 gal in your plastic race jug you should use it real soon, it is starting to get old.
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Any pitfalls to avoid in using up "not so fresh" race gas by running it in the tow rig, a lawn mower or other small engine, mixed for a chainsaw or weedwhacker etc?
If the engine you run it in has an O2 sensor for emissions or a catalytic converted the lead will "poison" them both and reduce their efficiency. It won't kill them out right but will greatly accelerate their aging.
The O2 sensor will get sluggish and not respond as it should and eventually will fail, same goes with the catalytic converter the lead plates out on the catalyst and reduces its effectiveness so you may end up buying a very expensive catalytic converter in exchange for saving the cost of a couple gallons of race gas if you do it routinely, a once in a while event probably will not make much difference especially if it is mixed as a very dilute mix.
In a weed whacker or lawn mower that does not have emissions concerns not much harm other than a little build up of lead deposits on the valves etc. If you mix it in low dilution in those engines not much cause for worry about damage. If you know someone who runs leaded race gas at a local drag strip on an old classic car that was built for leaded gas you might give it to them while it is still fresh.