C1 Fuel Injection Octane needs.

[Dan H.]

Re: C1 Fuel Injection Octane needs.

Jim

I agree with you. Again.

I've been driving fuelies for just about 50 years. (57 FI BelAir in 1963, then Corvettes since) They all had some minor hot restart/idle issues but not as bad as with today's E10 fuel.

Fortunately for me, there is ethanol free fuel about two miles from my house.

Must also agree, fuel today is a lot more work when restarting. Drove my 59 FI from San Diego to Bend Oregon in 1978, 100+ degrees outside on way up, temp gage pegged on 'H' until we hit some shade in Oregon. Restart was a little rough, but cleared right up and away we went. Now, anytime I shut off the 64, get the ilregular running until I get some cooler fuel into the spiders. Not much choice for gas in Kalifornia now adays!

[Michael W.]

Re: C1 Fuel Injection Octane needs.

Jim

I agree with you. Again.

I've been driving fuelies for just about 50 years. (57 FI BelAir in 1963, then Corvettes since) They all had some minor hot restart/idle issues but not as bad as with today's E10 fuel.

Fortunately for me, there is ethanol free fuel about two miles from my house.

Mike-we're not picking on Satan Ethanol this time. It's pump fuel in general, including pure gas. The OP is under the impression that FI cars cannot use it.

[Bob J.]

Re: C1 Fuel Injection Octane needs.

The answer from each of them is 'it's no worse that back when 'gas was gas'. I took that to mean it's the nature of the beast.

I disagree with that also.
I've owned at least one 63-65 FI car each of the last 43 years.

[Jim L.]

Re: C1 Fuel Injection Octane needs.

Mike-we're not picking on Satan Ethanol this time. It's pump fuel in general, including pure gas. The OP is under the impression that FI cars cannot use it.

What hands-on experience have you had with fuelies?

[Michael W.]

Re: C1 Fuel Injection Octane needs.

I disagree with that also.
I've owned at least one 63-65 FI car each of the last 43 years.

Again it might be a regional thing. Given the reports of what you guys in the south need to do vs. us furriners I can't help wonder.

[Michael H.]

Re: C1 Fuel Injection Octane needs.

Again it might be a regional thing. Given the reports of what you guys in the south need to do vs. us furriners I can't help wonder.

That's very possible. Likely, in fact.

Not just the local fuel mix but also the temperature for which the fuel is adjusted.

I can only report what I have seen with my cars.

They seriously dislike E10.

For me, it's pure-gas or 100LL aviation fuel. I haven't used 100LL for years though.

I see absolutely no need for 110 oct racing fuel. I think that's a waste of money.

[John D.]

Re: C1 Fuel Injection Octane needs.

The answer from each of them is 'it's no worse that back when 'gas was gas'. I took that to mean it's the nature of the beast.

Michael Ward, Seems every time we have this discussion it's basically between you and the rest of the DB members. Hate to tell you but you are 100% incorrect on ,"It's no worse that back when gas was gas". Yes 100% incorrect. If you would like you are welcome to come and visit me for a day or two and listen in one the phone calls I get from all over the USA.
The Ethanol crap has made the FI units worse than ever. I have been driving a fuel car since I was 18 years old. That was back in 1961. Yes we had minor issues with perculation in the old days but nothing like today. And it's only going to get worse.

One thing nice is we have the viton rubber parts, etc so the FI units can be run on ethanol is better fuel is not available. But they won't perform as well.
And that's putting it in mildly. And one other thing. Please don't let your fuel car and even your carburetor car sit too long with ethanol unless you have a fat checkbook.
By the way if you don't pay attention to your cars and you are using ethanol you better keep a close eye on them as it won't take much for a fire to start as ethanol destroys the cheap rubber parts. John

[Michael W.]

Re: C1 Fuel Injection Octane needs.

Yes we had minor issues with perculation in the old days but nothing like today.

Thank you. As to how much worse it is according to you vs. others is subjective. The guys that I know say no difference.

Michael Ward, Seems every time we have this discussion it's basically between you and the rest of the DB members.......................Please don't let your fuel car and even your carburetor car sit too long with ethanol unless you have a fat checkbook.
By the way if you don't pay attention to your cars and you are using ethanol you better keep a close eye on them as it won't take much for a fire to start as ethanol destroys the cheap rubber parts. John

I could suppose I could ask why the old sky-is-falling-satan-ethanol stuff gets dragged out again and again. NOBODY is/was talking about E10.

My own car, a regular driver, sits for six months a year over the winter and restarts just fine in the spring on last year's fuel. The carb has not been touched since the early 90s. A picture of the car can be found in my avatar when we were at the Texas Motor Speedway on our way to Galveston so it's got some miles on it- unlike some garage queens.

Since there's a demand for first person evidence, here's a picture of the inside of my fuel tank that has has nothing but E10 since 1996. Please convince me that I've got a problem...........

http://wm41.inbox.com/thumbs/107_ad3f6_39d819a_tn.jpg.thumb

[Bob J.]

Re: C1 Fuel Injection Octane needs.

What hands-on experience have you had with fuelies?

Jim, I doubt you will get an answer but we all know what it would be.

[Jim L.]

Re: C1 Fuel Injection Octane needs.

Jim, I doubt you will get an answer but we all know what it would be.

Yep. I've already drawn my own conclusions, Bob.

[Michael W.]

Re: C1 Fuel Injection Octane needs.

As have I.

[Duke W.]

Re: C1 Fuel Injection Octane needs.

That's very possible. Likely, in fact.



For me, it's pure-gas or 100LL aviation fuel. I haven't used 100LL for years though.

I see absolutely no need for 110 oct racing fuel. I think that's a waste of money.

Apple and oranges. Avgas uses the Aviation Method to rate octane, which generates a number very close to the Motor Method.

"110 octane race gas" is most likely RON.

PON = (RON + MON)/2, and the difference in RON and MON is typiclly 8-10, so 110 RON race gas has about the same detonation resistance as 100LL avgas, and they're both about 104-105 PON, which is greater than the 103 RON (98-99 PON) minimum placard on L-88s.

The only reason to use either of the above fuels in a Corvette is to eliminate the percolation problem because they both have higher midrange distillation temperatures, but the octane is unnecessary.

Everyone has to individually choose whether paying double the price of pump gas and the logistical issues are worth the the inconvenience of dealing with percolation, but the insulation discussed here and in previous threads eliminates or mitigates the problem to the point where it is little more than a minor annoyance.

Duke

[Michael W.]

Re: C1 Fuel Injection Octane needs.

but the insulation discussed here and in previous threads eliminates or mitigates the problem to the point where it is little more than a minor annoyance.

Duke

Exactly.

I am disappointed that yet again instead of an open, honest discussion of how best to deal with the realities of today's fuels, all the old myths and legends get dragged out with the usual threats of 'bad things happening'. This in particular does a disservice to new owners who just want a straight, complete answer preferably with all possible options and a good solid explanation of 'why'.

A challenge was made above asking for any owner to speak up who could operate his FI car on pump gas. This was promptly answered in the affirmative. This apparently has been dismissed out of hand. My own knowledge and observations obviously have no value as do the experiences of others. Why ask the question if the answer is going to be ignored or dismissed? The OP was and apparently still under the impression that his car needs 110 octane or higher fuel to operate satisfactorily.

For reasons unknown, the topic was hijacked to E10 and again the standard myths and misunderstandings dragged out and again real world evidence to the contrary is ignored.

Pretty sad.

[Timothy B.]

Re: C1 Fuel Injection Octane needs.

FWIW, On a carburetor car I think GM or Holley made a shield that extended out near the end of the float bowls and I know this will make a huge difference in gasoline temperatures. Wiring the heat riser open on my 67 also made a huge difference in the gas temperature, the air flow through these cars with the hood shut and that low air cleaner must be terrible.

I don't know much about FI engines but it makes sense that the spider lines would get very hot. I understand there is no heat riser and in addition to not needing the exhaust heat for vaporization keeping the heat from the plenum seems logical. Other than changing gasoline the design is what it is, I guess advancing the timing might help cool as every little bit helps but that heat soak with ethonal gas is most likely unavoidable.

[Duke W.]

Re: C1 Fuel Injection Octane needs.

The OP is apparently new to FI Corvettes. His original question was about octane rating, and I surmise that he was under the impression from others that "110 octane" was necessary to avoid detonation.

I think we all agree that this octane level is not necessary for a FI (or carbureted) Corvette with something close to the original as-built CR (which is typically half a point less than advertised). The real issue is percolation.

Avgas and race gas have higher distillation curves and are much less prone to percolation than E10 pump gas because ethanol lowers the mid range boiling points by up to 40 degrees. (Look at the distillation curves in the pdf I linked to in post #19 in this thread.)

The only reason to use avgas or race gas for 99 percent of vintage Corvettes, either FI or carbureted, is to avoid the percolation issue. (The other 1 percent may actually need higher than pump premium to avoid detonation.)

So the real question is about percolation, not octane, and the OP has apparently choosen the race gas solution rather than the other less expensive and less hassle solutions offered in the thread.

Duke