ronnie993tt

I only use Shell V in the 993tt because it is much cleaner and the ECU seems to adapt. Just check out your exhaust pipes for the corn syrop soot. I use S94 in my 260Z because there really is more ooomph and no ping, but it is filthy so I run Shell V in it if I'm in town a lot. Wish Shell V was at least 93 octane.

FFaust

++++1 Think we could write them a letter and ask for it?

FFaust

So Danny, how come you didn't vote for S94? The poll still shows 0 votes.

Ronan

I have never thought of using an octane additive. Does anyone do this?..any negatives?

DHI

Quebec no longer has Sunoco stations.
PetroCanada is our source for 94 octane juice.
Odd how no one has mentioned that yet?

Matt Lane

Lots of posts on this elsewhere, but for hot summer driving that includes track, 94 is probably a safer bet (even with 10% ethanol). It's just extra insurance against detonation. Not to mention folks spend thousands of dollars on mods for a relatively few HP - completely ridicuous to driving around with retarded timing from the DME.

For long-term sitting around (winter storage), cold weather, or old fuel injection systems, clearly non-ethanol fuel is the choice.

But just like oil choices, I am sure there is someone that's going to pipe in and assert that 5W-40 is the viscosity of choice for air-cooled track cars...



Best,

Matt

Matt Lane

No ****. Assuming your ECU mod retains the knock sensor which I am sure it does, you are feeling the effect of backed-off timing when using inadequate octane.

The effective compression on forced induction engines makes this even more critical. I wouldn't dream of running a turbo (or super) charged engine without the minimum recommended octane. In fact, I'd probably get a barrel of 100 to mix in as insurance and run a few points higher.

Best,

Matt

Radcap

Hey, Vpower, We have some retailers out here that blend corn/wheat/lawn clippings etc into their gas as well but I have found Shell to be the best in the Porsche as well as the Olds (though I would like lead in it).

Cheers,

Rod,

FFaust

$$$

FFaust

Matt, I agree with your comments but how would you explain the survey results? Pack mentality?

As stated above, I have switched to V-Power due to the "concern" over ethanol but I must admit that I am uncomfortable with its low octane rating.

You seem to know what you are talking about. Would you care to elaborate on your comments? It really is a bit obscure at the moment. Should ethanol really be a concern or is octane the only parameter worth tracking?

I have sent an e-mail to Sunoco to ask about this and will report if they do.

Jake Ok

The higher the octane the better, especially for Turbo cars. Don't take my word, ask your master mechanics.

If you doubt the marketing for Sunoco on the ethanol than the same goes for Shell V- power.

hopeforcash

I just switched from S94 to V91 for the last 4 fillups and I found my 03 - 996 nonturbo runs noticably "smoother" with the V91 on startup. Once warmed/hot not much difference. No track for me yet. Also with normal driving, I am getting better milage on the V91 than on the S94. Have anyone else noticed this?

JDSStudios

This topic was around several times. Someone posted a link to documents containing info
on Ethanol damage, and Porsche not really saying it is a good addictive- only that later
engines are more tolerant.

Some people think Octane rating is all about explosion power and more performance, when it really is
more about resistance to engine knocking. I did not notice any change in performance, and better yet,
the throttle body has not needed cleaning ever since changing to Shell 91.

Ethanol also affects rubber components, and possibly poly plastics in fuel injectors- someone correct
me if this is wrong, it has been a while since I read those docs.

Scary also is the separation of Ethanol from gasoline within 90 days, as well as Ethanol being hygroscopic (absorbs water).

It is also nice to see a cleaner exhaust, without all that black sh-tuff on it.
Shell all the way, or should I say, no Ethanol all the way.

Christien

fwiw, I've never noticed any difference in performance between Shell 91, Sunoco 94, Esso 91 or even regular cheap stuff, the few times that's all that's been available. I figure even the cheapest stuff available today is better than the best stuff they had in 1972, so it's not surprising I don't notice any difference. I use the Shell 91 in the hope that it'll be better for the engine over the long run.

Cosmo Kramer

Ultra 94 is the only thing that will keep my 7 psi S/C 928 from detonating at high RPM's. I even hooked up the octane loop on the computer to retard the timing 3 deg and it still pinged on 91. Ultra 94, no problem stock timing. It is a little sooty out the pipe though.