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How Inconcenvient is Race Gas?

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Hi TT, I am looking at picking up an 06 CR250 that has had the cylinder decked and the head cut for race fuel. For those of you that run race fuel, how inconvenient is it in the long run? Is it worth the trouble and extra cost associated with it?

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I have the compression bumped up on my ktm 250xc. On pump gas it will detonate. I mix 50/50 cam2 110 octane and 92 octane pump fuel. I can get the cam2 locally for about 9$ and change a gallon. I have also ran vp c12 but the best price I can get it for is 88$ for 5 gallons so it is considerably more. I don't find it inconvenient or a bother. I did notice that the jetting is slightly different between running the cam2 and the vp. The bike runs slightly richer with the cam2. I run a lectron and contacted them about it. They said it is entirely possible due to the different make ups between fuels and to pick one and stick with it. Neither fuel is oxygenated so I didn't think it would matter but it does.

 

I sent my head out to be modded and it was supposed be for pump gas. Well that is far from the truth. The bike is much snappier with it so I haven't taken it off. I had no plans of running race fuel and will go to a different head so I can run pump gas soon.

 

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I have a trials bike that only runs right on race gas.  It's expensive and inconvienent.  While on a dyno you might pick up a few peak horsepower by running s high compression head, thinner base gaskets or milling the cylinder or head.  But I find that throttle response kind of sucks on race gas.  Race gas, at least the leaded 112+ non-oxygenated stuff, burns very slowly.  So in my experience maybe more total power wide open but noticeably worse throttle response.

 

Honestly, if you're not racing and competing at a very high level I'd never choose to modify my bike so that it requires race gas.  Unfortunately for me it's pretty common for a lot of the European trials bikes, especially those older than a few years old to require it.  I actually lowered my compression with a thicker base gasket and richened the throttle tip-in with a richer carb slide but it still knocks and stumbles at 1/8th throttle  on our oxygenated 93 octane.

Doc

Edited by Doc_d

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OP, if you can reach the engine builder, ask what is the minimum octane the engine mods were intended for.

 

Most will run straight race fuel out of convenience, say 108 or 110 octane out of the can when perhaps their engine would otherwise run fine on around 96 octane.

You can then blend premium pump unleaded with just enough race fuel to reach the desired octane, link: http://www.motorsportsracingfuels.com/OctaneCalculator.html

 

If the bike is clean and really worth buying but you don't feel like messing with race fuel mixes, maybe look into finding a stock un-modified head.

Edited by mlatour
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I run a 50/50 VP 110 and 93 octane.  It's no more inconvenient than putting oil in the gas.  I pay about 7 bucks a gallon for it.

 

With all due respect to william, it has nothing to do with overall speed, my head cut gives my 200 a bunch more grunt off idle, which is very helpful in certain situations in the woods, nothing to do with overall speed.  It's a tuning tool imo, no different than adjusting a pv, or tweaking a carb.  Honestly, the way my bike is set up it's slow, but I have the power where I want it.

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Not inconvenient for me but then I only run it in 1 of 4 of my race bikes as that bike was built and intended for it use during wide open desert races and certain GP events. But I'm also able to go straight to pump gas once over 4500 elevation since it doesn't help at higher elevations as everything richens up. 

So MLATOUR and Doc_D are basically SPOT on, there is a purpose for it and sometimes even if your motor is not built for it you can yield better results as race gas/octane also affects how it burns and affects pre-det along with cylinder temps. You'll find in life there is always a time, place and setting for just about anything. You have to figure out though if/when it is or isn't right for you. 

What is inconvenient though at times is getting rid of the metal gas cans when done if/when you are not able to get from a drum or pump and have to buy canned. SUCKS... 

Edited by Diamond-Dave

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Thanks for the replies everyone, I just called the shop that did the work (Vey's Powersports in San Diego area) and he said that the motors are built with VP C12 in mind. The tech that I spoke with said that, to his knowledge, that as long as I run 108 octane or higher I would be safe. All due respect to William as well, but I completely agree with the above.

 

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Myself run a mild blend of 91 pump premium and 110 octane for a total of 94 octane in my YZ125.

 

The only mods consist of modestly reducing the compression squish height by 0.2mm (1.17mm) and leaving the dome cc's stock

which only raised compression 5psi (I get 180-185psi on a fresh top end, very decent for a 125) but that should not warrant race fuel. 

 

The reason is I tend to jet my engine rather on the lean side (short straightaways / slow tight corners MX tracks)

and feel the extra octane gives me a safety margin against inaudible detonation if ever I get a bad batch of pump gas.

Edited by mlatour

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2 hours ago, William1 said:

No, it is not worth it. A stock bike is plenty fast enough for all but the expert and pro riders.

I do agree that a stock 06 CR250 is plenty fast enough. ;) My son had one and sold it a few years ago, that bike had a ton of power and handled pretty decent.  He is always kicking himself for selling it.  I doubt 95% of the riders out there can even use a stocker of that bike to its full capability.

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I buy mine at a local dealership, or straight from the oil company.  If I bring my steel can it's 7 bucks a gallon, or I pay about 45 bucks for a 5 gallon VP can.  I prefer the sealed cans for some reason, I know the bulk is the "same", but my OCD prefers a sealed can.

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22 minutes ago, Kevin Milne said:

Thanks for the replies everyone, I just called the shop that did the work (Vey's Powersports in San Diego area) and he said that the motors are built with VP C12 in mind. The tech that I spoke with said that, to his knowledge, that as long as I run 108 octane or higher I would be safe. All due respect to William as well, but I completely agree with the above.

 

I live in San Diego and I ran vp110 for years.  Soco Fuel Group in El Cajon sells vp110 at the pump for 8 dollars a gallon, that's where I got my fuel.  No it was not inconvenient for me, I used to go to Motoworld for parts and get fuel at the same time once a month.

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Just now, 96motorhead said:

I live in San Diego and I ran vp110 for years.  Soco Fuel Group in El Cajon sells vp110 at the pump for 8 dollars a gallon, that's where I got my fuel.  No it was not inconvenient for me, I used to go to Motoworld for parts and get fuel at the same time once a month.

Sorry I should have clarified, I am not in san diego I live in Phoenix. That is just the shop that did the work to the bike I might buy.

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I run a Light leaded race fuel diet , not really for the octane, but the motor longevity, lead oxides eat carbon and lubricate dry top ends. Especially on a 4 stroke, if you don't use oil, then your topends run fairly dry. 

My local carries the 5 gal sealed cans VPc12,  $72 , very convienient  and no doubt what you are buying.

But for lead lubrication and cleanliness , you only need a cup or cup and 1/2 per tank.  Still more than enough to clean all the way to the exhaust tip, and lubricate everything needed.

 

I actually have catted sport bike with 112,000 miles, never had the valve cover off , never a motor issue.

 

Ktms , DRZ's, have all been on the diet and all High mileage , highly used bikes.

 

Edited by Spud786

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1 minute ago, Spud786 said:

I run a Light leaded race fuel diet , not really for the octane, but the motor longevity, lead oxides eat carbon and lubricate dry top ends. Especially on a 4 stroke, if you don't use oil, then your topends run fairly dry. 

My local carries the 5 gal sealed cans VPc12,  $72 , very convienient  and no doubt what you are buying.

But for lead lubrication and cleanliness , you only need a cup or cup and 1/2 per tank.  Still more than enough to clean all the way to the exhaust tip, and lubricate everything needed.

 

I actually have catted sport bike with 112,000 miles, never had the valve cover off , never a motor issue.

 

Ktms , DRZ's, have all been on the diet and all High mileage , highly used bikes.

 

Thanks for the info, the builder said I would need it for the octane. Is there anything I need to look for in regards to lead content?

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10 minutes ago, Kevin Milne said:

Thanks for the info, the builder said I would need it for the octane. Is there anything I need to look for in regards to lead content?

VP 110 is leaded fyi.

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2 minutes ago, Kevin Milne said:

Thanks for the info, the builder said I would need it for the octane. Is there anything I need to look for in regards to lead content?

I would try to get away without running full strength for your pocketbook , maybe a 50/50 mix would be sufficient.  C12 runs in everything, also a very stable fuel .

C12 has about 5 to 6 grams lead per gal  (they don't post the specs any more for some reason), but its plenty. 

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1 minute ago, Spud786 said:

I would try to get away without running full strength for your pocketbook , maybe a 50/50 mix would be sufficient.  C12 runs in everything, also a very stable fuel .

C12 has about 5 to 6 grams lead per gal  (they don't post the specs any more for some reason), but its plenty. 

I certainly agree that race fuel isn't an affordable proposition. However, it is probably more affordable to run race fuel than to run pump and have it detonate. I will probable start with a small splash of pump and slowly bring it down from there until it starts to ping, then I know how much octane I actually need.

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