Scott M Posted May 9, 2003 Report Posted May 9, 2003 Supposedly you don't "need" to run race gas until 160psi+ but does it help performance at lower psi? Is it worth buying at 145 or is it just a waste of money? Go fast now, look good later! Scott []v[] Quote
MSNIPER Posted May 10, 2003 Report Posted May 10, 2003 IMO it would just be a waste of money.It will do nothing for you. Quote
THX-1138 Posted May 10, 2003 Report Posted May 10, 2003 pump gas is fine for 145lbs but I have advanced my timing and with a shaved head I am at 145lbs also so I run a 50/50 mix of VP110 and 92 pump gas. at the dunes I will ping on pump gas so running the half mix works very well. and saves some money @ 5.75 gal for VP. ouch. Quote
Scott M Posted May 10, 2003 Author Report Posted May 10, 2003 Hmmm.. I plan on doing a 5 degree mod, so after that I will feel a difference w/race gas? I have been dong the same 50/50 w/octain 93/110 and have felt no improvement thus far, but I have also been changing jetting almost every time I ride.... Quote
THX-1138 Posted May 10, 2003 Report Posted May 10, 2003 + 5 will be a big inprovement. gas don't make power tuning is how to make power. Quote
Forcefed Posted May 10, 2003 Report Posted May 10, 2003 Think of it like this....you advance the timing/increase comp to make power---you use a higher octane fuel to compensate for the advanced timing (if your at the threshold of your CR on pump fuel)----therefore (and I`ve seen this on a dyno) for every point of octane you are using that you DON`T NEED, your actually retarding the timing and LOSING horsepower. Octane is just to keep detonation (pre-ignition) at bay. Using an octane level that you don`t need is not only a waste of money, but a substantial loss of HP/torque! THX-1138 is right on, the only ways fuel can make you power is: if your not using a high enough octane for you CR/timing in the first place or if you are dealing with oxygenated fuels like the VP MR series. Nitro and alky are cool too! :twisted: Quote
Scott M Posted May 11, 2003 Author Report Posted May 11, 2003 Thats what I mean by "race gas"=VP, trick,etc. Well you have managed to touch on the 2 things that still confuse the hell outta me - especially when combined! So now I'm totally lost, I just need a yes or no answer to: 145psi + 5 degree advance = use 93 octaine, correct? Quote
Bense Posted May 11, 2003 Report Posted May 11, 2003 yeah alky would be the ticket if you are want to make big power. I would not suggest Nitro. The prob with alky is that it burns twice as fast. But on the other hand is put as much fuckin compression as you want to that thing. So pretty much big power. You must be careful running alky though. I would drain everything after each trip. Alky does not like aluminum and will gell up on you in aluminum. So make sure everything is stainless or plastic. If you have anything aluminum then make sure you don't leave alky sitting in it. As far as 145 psi. I would just run pump gas. No need to spend the money. Quote
Forcefed Posted May 11, 2003 Report Posted May 11, 2003 Yes, in an earlier configuration on my ride, I was at 150 psi and 7 degrees advanced using 93 octane with no detonation....you should be fine. Run it, read your plugs for signs of aluminum specs (see BenBB`s jetting guide for a more specific way of doing this) and have fun! Quote
Mighty_Abyss Posted May 11, 2003 Report Posted May 11, 2003 you also have to remember that a pump gas will have more contaminants and wont be as pure as race gas. In my buddy's 250R 3wheeler on regular pump gas it will lose to me every time and when he puts race gas in it, it will beat me almost every time. It's definitely faster with the race gas in it. If you can find the right octane race fuel compared to what your compression is, you'd be the best off. If you can run 100 octane race fuel in your shee without preignition it'd be better off then running 108 or 112 but I would think that running 108 or 112 would be better off then running pump gas because of the purity of the race fuel. Not to mention it will drop faster then regular pump gas. Just something else to think about Quote
Forcefed Posted May 11, 2003 Report Posted May 11, 2003 If you use a fuel with more octane than you need, you WILL LOSE POWER due to timing issues! :!: Quote
Mighty_Abyss Posted May 11, 2003 Report Posted May 11, 2003 I'm not trying to argue that you wont lose power running to high an octane than what you need. That's saying you are running a fuel with the same characteristics. Example being VP Red and C12. My bike runs better with the VP Red then the C12. Racing fuel is a much cleaner fuel then pump gas is and thats why I think my buddies 250R runs better on race gas then the pump gas. I was just saying that its something else to think about. I know when I do a plug check with regular gas I'll have enough carbon buildup on the plug edge to do a good wot run in about a half hour of riding but with race gas it's pretty hard to get a good wot run because of the lack of any kind of carbon build up from the impurities in the fuel. Quote
Forcefed Posted May 11, 2003 Report Posted May 11, 2003 So your buddies 250R receives more power from the cleanliness at which the fuel burns vs. the HP/Torque lost due to the retarding of his timing? Hmmm... Please don`t take this the wrong way, its just a good discussion. Quote
Forcefed Posted May 11, 2003 Report Posted May 11, 2003 ScottM, I have to make a revision....There are so many other factors that we are not considering...the UCCR, squish angle, etc... Listen for detonation and increase/decrease octane levels accordingly. Quote
SCOTT H Posted May 12, 2003 Report Posted May 12, 2003 We run 93 octane with 8 degree advance with 150lb of compression,the bikes don't detonate.they actually gained a quicker 4-5 mph. Quote
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