93 pump fuel???????

marc walsh · Joined: 11 May 2011 Posts: 142

Race Gas is getting pricy. Rotax Max only requires a max rating of 93. Has anyone seen a difference in performance or issues with a good Gas/eth mix like Amaco or equivalent?

jeremy shaw · Joined: 12 Sep 2012 Posts: 22

Go to page 2 on rotax forums and its halfway down titled rotax fuel. there was a lot of good debate on using 91 93 and racing fuel.

Brian Degulis · Posted: Tue Feb 12, 2013 8:32 pm Post subject:

I would stay away from ethanol it destroys everything it touches.

Brian

al nunley · Joined: 13 Nov 2006 Posts: 3066

Don’t know if you know what “octane” is, but you would think the maker of the engine would know what is best for their engine.
Octane is just a measure of a fuels ability to resist detonation, so “if” your mixture is right, and you’re not getting detonation, 93 octane should be just right. More octane will “not” help performance.
I like the EGT for checking mixture. Get the highest reading you can, on the low end, as well as on the top end.
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Chad Hartzell · Posted: Wed Feb 13, 2013 1:52 pm Post subject:

Ran ethanol based pump fuel @ 93 Octane last year for the MRP series. No problems whatsoever with anything from fuel line, to fuel pump, gaskets, etc... The key is thoroughly draining it all at the end of the race day.

We had to change main jet (richer) and float heights a little bit compared to the VP MS 93 we used to run, but nothing that proper testing and tuning can't solve.

I've got no issues with it and look forward to running it again this year.
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Russell Stevens · Joined: 15 Oct 2012 Posts: 100

1: As long as you are draining it every day ethonol is fine
2: As long as you are not running on the edge of lean ethenol is fine
3: As long as you have a fuel supplier who is consistant with the ethenol content, running ethenol is fine.

If the ethenol content changes, and you are running on the edge of lean... boom...

Just run 91 straight gas and you will be fine. The Rotax doesn't have enough compression to really require a higher octane.

Ethenol is hydroscopic, and corrosive. Talk to a local small engine repair shop about the effects on aluminum carbs.

If you must run E-gas tune conservatively, and add Green (marine) stabil if you are allowed.

Brian Degulis · Posted: Wed Feb 13, 2013 4:35 pm Post subject:

Yeah I guess if you want to adapt to it you can make it work but why?

Brian

Jim McMahon · Posted: Sun Mar 17, 2013 8:32 am Post subject:

Buy your gas from a marina and call it a day. Pump fuel can be a mixed bag in terms of content. Its not the octane thats the problem, its the changing composition. If you are talking about a sealed rotax motor I don't think I'd risk it on pump if a good marine source could be found.
Reasoning is that good marine fuel contains zero ethanol.
If you are stuck with pump then you hedge your bets by buying from a station with high fuel turnover and try and buy as soon as they have had their underground tanks toped off.

Or just run whatever comes out of the pump, whenever and hope you don't blow up.
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Cory Ross · Posted: Tue Mar 26, 2013 9:04 am Post subject:

If you talk to BRP the Rotax engine has been tested and is ready to use up to to 10% ethanol fuel. Sure you could still have the problems of ethanol absorbing water but as for it eating engine parts it is not much of a problem. I have been using fuel with ethanol for the past 4 months(15 running hours) and have not drained my tank or anything after using the kart. Everything in the carb and elsewhere is showing no signs of being eaten by the fuel. Carbs in older small engines do get eaten by ethanol but that is because they were not designed to run it in the first place.

Peter De Saegher · Joined: 26 Mar 2010 Posts: 57

Cory , do you notice a big gain in ^power using ethanol in your Rotax ?

Cory Ross · Posted: Wed Mar 27, 2013 5:48 pm Post subject:

The first day I ran the kart I used VP MS93, then I switched to Shell 91 from the pump and did no really notice any difference.

Cory Ross · Posted: Mon Apr 08, 2013 8:07 am Post subject:

Was talking with another racer yesterday with a lot more experience then me. He says his Rotax runs much better on Shell 91 then it does on VP fuel.

Nick Weil · Posted: Mon Apr 08, 2013 4:23 pm Post subject:

Cory Ross · Posted: Mon Apr 08, 2013 6:54 pm Post subject:

Salvie Zaccaria · Posted: Sat May 11, 2013 7:37 pm Post subject:

Rotax engines run very well on pump fuel and at that savings in cash what would it matter anyway. We always practiced on pump fuel and were forced to buy expensive race fuel on race day. The jetting changes slightly but it's no big deal. Just another way for the track to make money selling race fuel.
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