rotax fuel

jeremy shaw · Joined: 12 Sep 2012 Posts: 22

first post coming....just got a great deal on a rotax with a monza chassis.....anyways he said he ran it on 91 pump gas and a 2 stroke mixture of 33 to 1. Looking at manual it says RON 95. So what gas am i supposed to run?

Keith Buffo · Posted: Mon Sep 24, 2012 9:46 am Post subject:

A Rotax loves 93 (pump is fine). But the real answer is whatever the rules dictate where you race.
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jeremy shaw · Joined: 12 Sep 2012 Posts: 22

its just at club level they dont care about that.... they run 100's, tag and shifters in one class (there is only like 10 people that come) and im gonna be running it at scca events.......but in my area we only have 91....so is it find to run it off pump gas or is it better just to buy it from a auto store?

Nick Weil · Posted: Mon Sep 24, 2012 11:56 am Post subject:

Anything less than 93 and you will run the risk of detonation at higher RPM's as the fuel will want to 'burn' before the ignition actually takes place. I wouldn't risk it, but you said you were also going to be running 33:1 which is a lot more oil than the 50:1 most Rotaxians use.
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Nick Weil
Authorized Rotax Service Center and Dealer since 2002
2004 Team USA Rotax Worlds Finals DD-2 Driver

Want to save money AND grow the economy? www.fairtax.org

jeremy shaw · Joined: 12 Sep 2012 Posts: 22

so 50:1 is the way to go? the manual i got from the person i bought kart has it crossed off and 33:1. Most of the guys run the fireball they are running 7:1 that's crazy.

Nick Weil · Posted: Mon Sep 24, 2012 8:51 pm Post subject:

Most guys running FireBall's are going to buy multiple engines before you rebuild your Rotax once... LOL. In reality, they are probably running 7 Oz. oil to 1 gallon of fuel. NOT 7:1. You should be running between 2.5 and 4 oz. per gallon depending on your jetting and results of quality plug checks and carb settings.
_________________
Nick Weil
Authorized Rotax Service Center and Dealer since 2002
2004 Team USA Rotax Worlds Finals DD-2 Driver

Want to save money AND grow the economy? www.fairtax.org

Thom Andresen · Posted: Tue Sep 25, 2012 4:17 am Post subject:

Commercial grade pump high test fuel doped with 10-15% Ethanol is not advised.
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Joe Ricard · Posted: Tue Sep 25, 2012 4:34 am Post subject:

Our brand new track just got the under ground fuel tanks installed.

Just like a regular gas station buy with credit card. except you can buy 110, MS98, and real gas 93. It's so easy to walk over and buy an extra gallon of gas to get you through the day.
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Arrow AX-8/ Rotax Sr.

Justin Martin · Joined: 27 Mar 2012 Posts: 328

For breaking in and or Racing I use MS93 VP race fuels, otherwise I use 100 octane pump gas.

I have been told to run either of these two multiple times by many hardcore rotax guys

Joe Ricard · Posted: Tue Sep 25, 2012 8:34 am Post subject:

That's odd for a spec motor with minimum squish numbers, a combustion chamber that is not allowed to be changed, pipe is spec length and shape. port timing is spec.

What are we missing that 100 would make more power than 93 gas.
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Arrow AX-8/ Rotax Sr.

Rich Hays · Posted: Tue Sep 25, 2012 11:07 am Post subject:

we have run 91 octane pump gas mixed @ 32:1 (Motul and XPS)for years with no hint of detonation.

-rh

Nick Weil · Posted: Tue Sep 25, 2012 11:33 am Post subject:

Justin Martin · Joined: 27 Mar 2012 Posts: 328

Hmm really? I did not realize that. It was my understanding there would be an advantage, and everyone else around here thinks the same

John Savage · Posted: Tue Sep 25, 2012 3:42 pm Post subject:

Jeff Salak · Posted: Tue Sep 25, 2012 5:33 pm Post subject:

Most Rotax class rules will want you to use VP Motorsport 93. The spec Rotax fuel is this and its unleaded.
VP Motorsport 98 Leaded was once a popular choice too.

Here is the link to VP karting fuels.

http://www.vpracingfuels.com/page469676.html