mark kibort

Im still racing a nearly stock engine for racing (stock meaning , stock ecu, intake and head/cam/valves) There is a discussion of ethanol with the 928 folks and they are talking about the destructive power of ethanol on the fuel lines. i know most of the pure race cars run race gas (which i assume is not blended with 10% ethanol like street pump gas), but what about those of us that run pump gas? is it a concern?
How much of a power loss can we expect by running a pump gas with ethanol vs running the same octane of a race gas? (or non-ethanol added gasoline)

I remember running in WCGT where they made sure we ran sonoco race fuels and actually checked to make sure we had it in our car or be subject to DQ. i always ran the street stuff but ran it for the rules sake, in the race . i remember going to the dyno before and after and didnt see any difference but then again, i was comparing 91 street gas with 100 octane race fuel. maybe the higher octane off set its gains of the missing ethanol. of course i wasnt able to take advantage due to my ECU and cam configurations , so the extra octane was not a benefit to me.

Has anyone noticed a gain on the dyno when using different fuel octanes with no other changes to the engine set up settings.

Der ABT

Isn't ethanol and octane booster, my understanding is technically there is more potential energy in lower octane however because of the varied ignition point and higher temps in the lower octane you are unable to safely tune as high with out risking knock.

Higher octane is more consistent burn, and lower temps bit technically less potential energy......but you can in being able to tune more power in safely....
But if ecu d oesnt account for octane or your not allowed to tune shouldn't make mich difference besides higher run temps.

Not the most informed person but that was my understanding

Thundermoose

I am not sure that ethanol is octane booster. It has less power per unit of volume than gasoline. It was introduced as replacement for MTBE as an oxygenate. I think 10% ethanol is probably a hurt compared to non ethanol. Once you get to higher mixes the cooling effect takes over and you can actually get more hp though. I run 93 pump gas in my car. I have so much room to improve set up an driver that I don't fret too much about ethanol content.

Brian C in Az

Ethanol does cause fuel lines to deteriorate from the inside out. This is a big issue in the marine industry since many boats are now using pump gas instead of marine gas.

Marine gas, race gas, and aviation gas do not contain ethanol.

All cars since the mid eighties have come from the factory with ethanol safe/ resistant fuel lines and hoses. All new boats since the early 2000's have as well.

If you have an older car, then you simply change the rubber hoses because all fuel hoses sold in the US are ethanol resistant.

If you have an older boat, especially with a carburated engine, you should upgrade all your fuel lines.

rlm328

What Brian said, plus gas leaves a varnish like finish on the inside of the gas lines and tank. The alcohol will dissolve this varnish which has a tendency to plug up things like injectors.

CCA

There are a lot of different racing fuel blends, some have ethanol some do not. Here's Sunoco's listing - http://www.sunocoracefuels.com/fuels and I know VP has a bunch too. The Tech page at Sunoco has some good info on it too - http://www.sunocoracefuels.com/tech-corner As for fuel lines, well it is best to make sure the lines are able to handle ethanol, some can't and it will destroy them. Same with racing bladders, but as with fuel lines, most makers have adapted their products to be able to handle ethanol. Gas has SO many chemicals in it now it's crazy.

mark kibort

thanks guys.. thats some good info. but when i hear of the ethanol being a HP robber and a fuel line destroyer, i start to ask questions. my car is an 87 with very old lines , but you guys are saying if they are in good condition, they are resistant to problems. However, what about the HP loss of a normal street pump gas 10% enthanol Union 76 vs something you find off the beaten path with no ethanol or race gas at the track. worth the extra cash for a bit more power?

333pg333

Lot's of the modified 944 turbo crowd and the Jap car scene run E85 successfully for years. The claims that it will instantly destroy your village are somewhat exaggerated lol. It can have an effect on Alu but if you flush your motor out with pump fuel after events it will be fine. Many people don't even bother and there's no public outcry.

However, you can't just substitute E85 for pump fuel with no other changes. It's not a hp robber, you make more hp BUT you need to have the supporting mods to run it. Generally allow for ~30% more fuel needed which will almost certainly require larger injs and fuel pump/s. You'll also need a totally different tune. The benefit is that it's cheap and burns much colder. Best for forced induction but remember, the Aussie Supercar V8's (n/a motors) exclusively run Ethanol. Also every single entrant in World Time Attack down here runs E85 and the top cars are waaaaaaaay faster than say a 991GT3RSR around a track.

So yes, you can make more power but you can't just chuck it in your tank. Motor will blow up as it will run way too lean.

bpu699

E10 does get lower mileage and less power. Even when I just fill my toyotas, with e10 I lose 2-3 mpg...

Your old fuel line are likely rock hard on the inside, and oddly, this is protective.

I recently replaced fuel lines on a 88 930 and 87 testarossa. The fuel line were hard, but the inside looked perfect. The e10 didn't eat them in the least.

Now, if you put in new rubber fuel lines, good luck. They melt within 2 years. Gates sell some with a barrier shield that supposedly makes them better. But they don't come in larger sizes or metric... Which sucks...

The old lines don't seem to internally degrade... They may eventually crack, but that's a whole different issue...

I reall want to run race gas, but it's leaded, and that apparently kills oxygen sensors and afr meters...

Bo

mark kibort

sounds like anything but a big difference then. fuel lines in the modern era cars are made for a little ethanol, and the power loss is probably not noticeable? (or measurable). as far as race gas, most offered at the track, is unleaded as well, so that isnt a big deal for the sensors or cat.

JasonAndreas

For a number of years the sky was falling with respect to the 964/993 fuel lines and ethanol. Then one day a Rennlister looked up the part numbers with the fuel line manufacturer and discovered their polyamide fuel lines have no problem with ethanol. Somebody must've done the same and researched the 928 fuel lines in one of the manufacturer's (cOhline? Gates?) catalogs or called them directly?

Spinout

I was in the hot pits this past weekend @ Petit. The IMSA official told us all cars ran on E20 which is 20% ethanol. Fact or BS, I don't know...

mark kibort

I guess, the point has been made that as long as you tune for it, and pump more into the engine, the power levels can be close to the same.
I'm more concerned about a direct comparison of non-ethanol based pump gas compared to race gas at the same octane levels. it would be interesting to see some dyno results of such a comparison with no other changes.

Der ABT

https://extension.psu.edu/fuel-ethanol-hero-or-villain

mark kibort

great little article .. thanks! looks like we lose about 3% HP, but gain some extra octane.
(and possibly a cooler combustion charge)