Howdy,

My local Shell service station has recently added "Shell VPower - Racing", which is a 100 octane fuel with 5% ethanol.

What impact will running this fuel have over running the standard "Shell VPower", which is a 98 octane fuel but without any ethanol in it? Is ethanol bad for RX's?

My understanding is the higher the octane the better in terms of power and preventing detonation. Since most of you guys seem to be in the states running relatively low octane fuel, does running these higher octane fuels make running higher boost safer?

My RX was recently dyno'd and boost on my primary turbo reached 12psi, all on a completely stock RX with a cat back. The guy dynoing it (Anthony at Maztech in Melbourne Australia), said this was fine. It made 182RWKW...

Thanks!

 

my understanding that unless your tuned for the higher octane fuel, it wont help you, except in preventing det. someone correct me if im wrong.

 

I think ethanol burs cooler, thus lowering the chance of overheating (Please correct me if I'm wrong)

I'm not sure what the 5% would do...

maybe burn a little cleaner.

 

thats the whole point of a alky based fuel is to lower temps and decrease the chance of detention/knock. if you have less of a chance to knock then you can turn up the boost to say 16-18psi before reaching the same knock levels you were hitting at 12psi on 93 oct. or without any alcohol. you dont really have to "tune" tho. im currently running 93 oct. gas with alky injection. good luck tho.

Aaron

 

Im pretty sure you have to tune for the 5% ethanol or you will run lean.

https://www.rx7club.com/showthread.p...hlight=ethanol

 

good link...i'd prolly take his word. im not running the alky IN my fuel..but injecting it. hmm so idk..

 

Simply adding a higher octane fuel will not necessarily be "better in terms of power". Better in terms of preventing detonation-- yes. Which allow you to run higher boost without the risk of detonation.
Not in this instance. The addition of ethanol to pump fuel is more to reduce emissions than any performance gain...especially with only 5% added.
Just because you're running a higher octane fuel or "alky based" fuel doesn't mean you can indescriminately crank up the boost (and trying for 16-18 psi on stock twins is useless, as you're way beyond the turbo's efficiency level). Any higher boost levels than stock require some "tuning" if you're interested in your engine lasting.

 

IIRC our octane fuel isnt that much lower then yours, although it apears to be its because we use different rating systems although it may be different by a bit its not as much as it apears. correct me if im wrong but im pretty sure i heard this somewhere...

 

are you sure about the 5% Ethanol??? or it just a publicity stunt?

BP ulitmate here in Europe is 100octane and has no reference to ethanol...
(Shell is no longer in my country so... )

 

what he said^.
i believe your 97-98 octane is roughly equivalent to our 93. the 100 octane should be fine to run, but i wouldnt use it as an excuse to crank the boost more than 1 or 2 psi....

pat

 

Yeah!? Everything around here is 10% ethanol. The only "pure" 93 is BP. But, unfortunatly, my state government is trying to remedy that. Sucking-up to the farmers to get votes.

 

yeah down in southern IL. when I was visiting my grandma i saw the had a lot of stations running a 85%petro/15% ethanol bleend rated at 100 octane couldn't ever get a definitive about it on the forum at that time this was pretty new. but have found threw my own research that it is more corrosive the ethanol strips away oil so would probly want to be pre mixing to keep your engine lubricity and can eat some rubbers. sorry this dosn't really help

 

^^^ from what I have been told from a couple tuners and Gas station owners over here the above is true. A couple years ago they were using ethanol mixtures at all the gas stations but after they realized the stripping and rubber corroding affects the fuel with ethanol had they pretty much got rid of all of it. I have seen it on a rare occasion at some gas stations. It was very common before but now it is almost non existent here. I am not sure what percentages the mix was but could find out no prob if someone is keeping track of all these figures.

 

You can use the 100 oct with 5% ethanol without any worries.