wmf62

thanks Jim, i guess i've slept one too many times...
:o
Bill

jim lockwood

Naw, you're just still infatuated with your Rochester (E)FI system. And I'm more than a little envious.

Jim

wmf62

Jim
if it wasn't for the summertime problems i'd still be using the Rochester; ...as dinosaurs go, it's a simplisticly beautiful beast...
Bill

wmf62

just think of the 'fun' things we could have done if we had stayed in the Columbia area...

i wonder if Bob Stafford is still alive.....
Bill

jim lockwood

Life as I've known it on earth would certainly have been different if I had stayed in Columbia. I don't believe it would have been better. The left coast has been really good to me.

I don't think Bob would be more than about 70-ish, would he? He ought to still be kicking.

I bought my first FI unit from him back in '78. It was a screwed up '57 unit (is that redundant?) and I'm sure he knew that. I certainly didn't.

After I muddled through my first FI rebuild, not really knowing what I was doing, the unit actually worked and worked well.

One evening Bob was at my house and I casually turned the key to start the engine with his former FI unit on it. When the engine lit off, and settled into a nice idle, the instant astonishment that registered on his face was just priceless.

Jim

MikeM

I read his piece but I'm unsure if Jerry drew any conclusion other than E-10 and racing gas behaved differently.

I don't believe it says anywhere that a proper fuel curve cannot be maintained. He did say there was a difference between the two fuels but exactly how much wasn't mentioned.

jim lockwood

What he said is that the two curves cross in two places. That means that at least one of them is non-linear and that they certainly aren't parallel, able to be made concurrent by a stop screw adjustment.

rustylugnuts

Mike what’s your obsession with E-10, are you heavily invested with E-10 stocks, an agriculture farmer, or just put it on your cereal in the morning?

rustylugnuts

MikeM

Yes, I understand that part of it but it's implied not only is there a difference between race gas and E 10 it's also said that E-10 can/will cause serious engine damage such as burnt pistons, fouled plugs and blown head gaskets. That "difference" sounds very significant to me if true.

I just haven't experienced those problems in many years of running E 10in my cars, including Rochester FI, garden tractors, boats, and any number of small engines. So while I don't doubt there could be some difference in the characteristics of the fuels (even though I have no idea why) as stated, I'm curious as the the extent of the difference.

Mike Ward

Not putting words in Mike's mouth, but he's probably as sick and tired of the rehashed myths and misunderstandings (AKA BS) as I am.

As it turns out, the info above about the mixture 'going 10-15% lean' was based on use of E85 fuel (85% ethanol) and not E10.

wmf62

Mike & Mike
i tried E85 in my, as Jim calls it, (E)FI and didn't see any difference; but a few folks told me that it was a BAD thing to do and could cause problems to the fuel system and other parts.

at this point i have no clue as to what fuel or even what else this thread is about...

Bill

MikeM

My interest was this. DeGregory made a statement way back that you couldn't get a satisfactory air/fuel curve using E-10 as a fuel and it did not matter whether it was Rochester FI or a carburetor.

No facts or documentation were provided. Just a statement and then a "goodbye"!

As an aside here, one rebuilder uses a chassis dyno and racing gas to calibrate his units, the guy from Pennsylvania uses "who knows what" method but I'm reasonably sure it's not a dyno. Yet, both these guys turn out rebuilt/refurbished fuel injection units that seem to run well under most conditions and that includes using 93 E-10 gasoline.

I don't care anything about a comparison between E-10 and any other fuel. I'm just trying to learn something.

All I want to know is why/how? So far, I'm still searching for the answer(s).

genejockey

There may be some light at the end of the tunnel. The piston aviation industry is working on a no-lead substitute for 100LL with some success at least at a small scale. The big 550 CI turbocharged mechanical fuel injected engines run at 35-36 inches Hg manifold pressure. However, they've been at this for quite some time. We have the same concerns, especially with the compatibility of seals and gaskets with ethanol. We'll see...

wmf62

E85 got tossed in there somewhere/somehow...

i never had any problems (other than summer heat perc) using E10 93 with the Rochester on a 70 LT1...

so i'll hush, and listen; and hopefully learn something too



Bill

MikeM

Sounds like he showed you the picture of the bent connecting rod!

wmf62

i saw the pic and know it can happen; but i don't understand how it has anything to do with ethanol.... but then i have never had a anti-siphon/hydrostatic lock problem EXCEPT with the 80 Pontiac Bonneville with the 350 diesel they had at the time...

but i digress... i promised to hush...

Mike Ward

What set off my BS detector was the statement way up above that engine would run lean by 10-15% when using E10. This makes no sense.

In an extended conversation over on the VH board, a further statement was made by the same poster in support of the above claim, that the stoichiometric ratio of ethanol blended gasoline was 10:1 vs. the value of pure gasoline which is 14:69. For reference, pure ethanol is 9:1. The contention was the Rochester FI unit could not be calibrated to accommodate such a fuel. This is probably true HOWEVER-

E10 actually has a stoichiometric value of about 14.16 and E85 has a value of around 10:1.

This means that the 10-15% 'the sky is falling' value was based on use of E85 and not E10.

The units may suffer from hot start problems when using E10, but this is most likely due to percolation of gas formulations have an unacceptable Reid vapour pressure, but that's independent of the presence of ethanol. Pure gas can be just as susceptible.

Vettrocious

I'm not convinced that anyone here knows enough about E10 pump gas, racing gas, 100LL, or syrup, for that matter, to make definitive and/or generalized statements about how each performs in the extremely variable conditions FI Corvettes are driven in. (well...maybe we can say that syrup will perform lousy)

Each car is different, each fuel blend is different, each climate is different, each driver is different, and each FI unit/engine is set up differently. The matrix is huge and unwieldily.

My experience with 63 FI cars in Michigan will be totally different than Florida, Washington state, or California, as the fuel blends and weather conditions are completely dissimilar.

I've found that in Michigan my FI cars run great on racing fuel, good on 100LL (or premium pump with no alcohol), and awful on 10% alcohol pump gas. Others say different. OK, I believe them.

You'll NEVER sort this out globally, so decide for your car alone: run the cheapest stuff that keeps your idle smooth and isn't hard to start when hot.

Me, I run racing gas, 'cause I've tried them all in two different cars and the results are the same.

wmf62

amen... this was my experience in Florida too...
Bill

MikeM

This wasn't the issue but, thanks.

Maybe a local chassis dyno shop can shed some light on the issue.