Posts: 2953
Joined: 10/5/2012
Location: GBR
I keep reading that people use race fuel, mainly VP C12 and mixing it with regular petrol. My question is, what is the benefit of this? Is it better for the engine, gain more power?
I've got a YZ125, standard engine apart from aftermarket pipe & reed block, will I gain anything out of it?
We have super unleaded over here in the UK which is about 97 octane & I'll use Castrol A747.
Posts: 8551
Joined: 4/1/2008
Location: SD, CA USA
At the very least, you are using a consistent fuel. This is probably rare, but relying on regular pump fuel, you could get a "bad batch" and have detonation in the engine that can cause issues quickly or shorten engine life.
The other part is the ethanol in pump fuel these days that mucks up internals.
Posts: 1729
Joined: 8/25/2015
Location: Mansfield, OH USA
You get clean, consistent gas mostly. In most bikes they require a minimum of 95 octane. Not sure about you but no pump that ive ever seem has it. You get better throttle response & more power. If you got a bike with 13:1 CR or more it will really wake it up.
For your case specifically, youll mostly benefit from clean gas. My pumps around me have stupid amounts of sediment in it. Idk how my truck hasnt had a clogged injector.
2009 Kawasaki KX450F
2009 Kawasaki KX250F
2002 Suzuki GSXR 600
Posts: 1107
Joined: 10/28/2015
Location: Grand Terrace, CA USA
For 2 strokes unleaded fuel isnt good. 97 is pretty high octane for a pump gas. You wont gain much power if any from c12. I run c12 50/50 with 91 pump gas. I get better throttle response. It runs cleaner and takes away detonation from the horrible pump gas we have in CA.
Posts: 573
Joined: 2/6/2009
Location: Orlando, FL USA
I run a 50:50 mix to avoid ethanol but the only ethanol free stuff we have around here is 89 octane. The C12 will essentially eliminate detonation. I recently had some head and cylinder work done so I am running straight C12 now because...why not?
Posts: 205
Joined: 10/9/2015
Location: GBR
Edited Date/Time:
Muscle-Milk-KTM wrote:I keep reading that people use race fuel, mainly VP C12 and mixing it with regular petrol. My question is, what is the benefit ...more
No you won't gain anything. Use Super Unleaded from a proper garage. I've used BP 97 octane for years and if you're up north it also shouldn't contain ethanol, at least it never used to.
If you're running a motor with higher compression you can still buy four star (higher octane leaded fuel) from a couple of places, which is mostly all VP fuels are, so check if there is a place near you. It'll be cheaper than buying VP branded fuel too.
Posts: 2953
Joined: 10/5/2012
Location: GBR
I have a Shell garage at the bottom of my road so I always use V Power. I'm in the South East, why is the ethanol less up North?
I have a karting shop near me so I might give them a ring. Do I just mix it 50 50 with the Unleaded?
Posts: 205
Joined: 10/9/2015
Location: GBR
No idea why. That just applies to BP Ultimate though. I guess it was a decision made by the refineries and the ones down south added it, and the ones up north didn't. However it is harder to find high octane fuel up north as they're all too tight to pay the extra money for it.
Posts: 1706
Joined: 3/12/2012
Location: San Antonio, TX USA
I run straight C12 in my bike. I've gotten bad pump race gas before and the bike ran like crap. I've tested 91 octane pump gas in shifter karts back to back with C12 and there was a noticeable power increase and the engine pulled harder out of corners. I'm not a fan of $85 for 5 gallons of C12, but I know its good gas and I get about 4 days worth of riding out of it.
Also, if you run pump gas be sure to get it from somewhere that goes through a high volume of fuel so its as fresh as you can get. Storing in plastic containers shortens the shelf life of fuel to about 2 weeks before it starts to degrade. If you do the black cans are best to help stop UV rays, which also degrade fuels.
2018 KTM 250sx
Instagram CamaroAJ
Posts: 2953
Joined: 10/5/2012
Location: GBR
Posts: 205
Joined: 10/9/2015
Location: GBR
Edited Date/Time:
Well C12 is £5 a litre. Four Star is just over £2 a litre if you can get it. And 97 octane is just over £1.30 a litre and the bike is set up to run on it. http://www.trackstuff.co.uk/VP%20C12.htm
The other option is visiting a local aerodrome and asking if you can buy fuel.
Posts: 370
Joined: 1/1/2017
Location: NoVa, VA USA
For a 2 stroke, MRX02 with proper jetting, and you will be set. Garage will stonk like hell, but you will love the bike
Posts: 522
Joined: 2/17/2017
Location: Ravenna, MI USA
If u wanted a performance gain from gas then u need an oxygenated gas like vp 4.4 otherwise it's like others have said, its just good consistent fuel
Posts: 1152
Joined: 5/13/2015
Location: Harrison Twp., MI USA
Someone did a write up once and U4.4 gained over 1hp on a stock 450 with no mapping changes. I can't remember who did the article.
Race Bike: 2018 KTM 350SXF
Other Bikes: 1985 CR80R, 1990 CR250R, 1998 PW80, Yeti SB130LR.
Sold: 2016 YZ250F, 2012 CRF250R
Posts: 20108
Joined: 6/15/2010
Location: Bowie, MD USA
Posts: 6829
Joined: 11/30/2013
Location: Portland/Los Angeles, CA USA
Edited Date/Time:
On a race weekend in my 125, I’ll use C12 50/50 with T4E. Normal riding I’ll do C12 50/50 with 91 pump.
Posts: 7507
Joined: 10/31/2013
Location: PA, USA
If the engine does not require a fuel such as C12, you will LOSE power. The higher octane leaded fuels are used to prevent detonation in engines with high compression. Using a fuel such as C12 when only pump gas is required will result in an incomplete burn of the fuel, thus not burning all of the available oxygen. This theory that race fuel will give you more power in a stock engine is just not true. Oxygenated fuels, such as U4.4, will give you a noticeable increase in power and throttle response, but it is not due to the octane rating. It is merely due to the engine being able to burn more fuel as the gas itself is a carrier of more oxygen.
Mixing a stock two stroke 50/50 with C12 and pump is always a good idea for detonation protection. In the US our fuels are fairly inconsistent in quality. All of my mx bikes claim to only need 91 octane out of the box. On the east coast we have 93 octane at the pump...
Tomac and/or Anderson for 2020.....
Posts: 2724
Joined: 5/25/2014
Location: San Diego, CA USA
Posts: 484
Joined: 12/31/2014
Location: GBR
The c 12 is leaded which aids lubrication
Speak to Jeff at track stuff it works best on modified engines
Posts: 2816
Joined: 1/4/2014
Location: AUS
Posts: 476
Joined: 1/11/2016
Location: Belle Chasse, LA USA
On pro circuits jetting chart, which I would assume is exhaust equipped. It shows all 2 stroke testing was done with VP c12 with 927 at 32:1. Essentially stock bikes with exhaust and they recommend straight race fuel. They also show Jets for different fuels. I will be testing a kx 65 with some jetting changes and vp U4.4. I’m pretty sure I will see some type of gains.
https://www.procircuit.com/jetting-specs.htm
Posts: 2501
Joined: 12/16/2010
Location: AL, USA
Posts: 205
Joined: 10/9/2015
Location: GBR
It is. We use MON on our pumps, you use AKI. 97 for us is 93 for you.
We can get ethanol free fuel at a number of fuel stations and even can buy leaded fuel at a few. Also there are 7-8 refineries serving a country the size of two states so we don't need to transport and store our fuel for long, our oil comes from the North Sea which is on our doorstep and fuel quality is heavily regulated to the point a poor fuel shipment that damages vehicles makes national news. There is no reason for anyone in the UK to waste money on expensive fuel unless an extra 0.5-1hp is really needed.
The shorter life of components isn't an excuse either as running a £5 a litre fuel will cost me at least an extra £40 a day. I can run twice a week. Running pump fuel I could do a new top end every two weeks and still spend less than running race fuel.
Posts: 95
Joined: 6/14/2014
Location: Northville, MI USA
Personally .5-1hp isnt a deal breaker but throttle response is. If the engine pulls harder then thats awesome because i need all i can get. I run 93 in my 250f because we have it everywhere, but race day I'll run an oxygenated fuel like VP U4.4.
Jusr wish i had a vortex ecu or something so i could have different fuel maps
Posts: 2501
Joined: 12/16/2010
Location: AL, USA
I think you all use RON. We use RON + MON / 2 (Research Octane Number, Motor Octane Number, I think)
In the race to the first corner, my old fat self needed all the HP I could get. :-)
Posts: 2958
Joined: 11/3/2014
Location: Charlotte, MI USA
I can tell you that in sandy conditions that rob power..I can 100% feel the difference when using U4.4. If I do a trail ride or something is more relaxed I just use the best ethanol free fuel I can get.
Posts: 1602
Joined: 10/14/2017
Location: 86oh, CT USA
do any of you guys use race gas when you store your bike over the winter to help keep things from not gumming up?
Posts: 522
Joined: 2/17/2017
Location: Ravenna, MI USA
fourfourone wrote:do any of you guys use race gas when you store your bike over the winter to help keep things from not gumming up?
Actually some race gas will gum things up. I use non ethanol gas
Posts: 1581
Joined: 1/4/2013
Location: QLD, AUS
Posts: 912
Joined: 2/26/2017
Location: Gulf Shores, AL USA
Been running pump gas my whole riding career and im still slow. Maybe spending $10 a gallon will make me a better rider?
Idk, the ads on vital/racerx/mxa said it, so it must be true
