C1 Fuel Injection Octane needs.

[Paul Y.]

Re: C1 Fuel Injection Octane needs.

I agree with a few small reservations. I have driven my 63 FI coupe over 100,000 miles in the last 36 years. Some insulation of the spider has improved hot starts. I may insulate the fuel lines as Michael has described so well. I put in pure gas as often as I can get it. I have an app. on my phone when I travel. When I can't find it, I use the ethanol and it isn't quite as easy to hot start, nor does it get as good of mpg. (I check every tankful) but it sure does not keep me from the road trips and driving of the car no matter what the temperature. I make as much effort as I can to store the car with a tankful of pure gas in it. I usually inspect it every couple of years. I have always worked on it myself except for the first 3 times when Brian Futo was generous enough and kind enough to teach me how to work on it. Like Dan says, there is no comparison to a carburetor as they are so much smoother and quicker and get fantastic fuel mpg. I love fuel injection cars and I work on many for people for free for the love of them and wanting to see their cars run well also. I want to pass it on what Brian gifted me with. These injections are not rocket science. They are actually quite simple, and with a few unknown secrets, can be self maintained and driven often with much pleasure returned. Don't be afraid to venture out and enjoy them. You would be surprised at how many people can give you a helping hand. I suggest that if you own one or would like to, get to know all you can about it, and become one of those dreaded "do it your selfers" You could very well be surprised.

FWIW, I've driven FI Corvettes for 38 years, they were always different from carb Corvettes, but soooo much smoother and quicker. There are hot start issues but are a minor incovenience compared to their performance superiority above the carb equipped Corvettes. They are the high water mark of early technology so very worthy of their high standing in our Hobby. My current 1964 FI Coupe has run flawlessly for the last 20K miles on 91 octane Kalifornia gas. I do work on my own FI units, this one is the best, a 380, the most refined of them all. In todays world, if you want to travel beyond the city limits, you need to be able to run your FI on pump gas!!!! If it can't, then park it and go look at it in the garage from time to time. These great cars will run just fine on the current gas, some is better than others, but all will work. GET IT?Dan

[Duke W.]

Re: C1 Fuel Injection Octane needs.

These injections are not rocket science. They are actually quite simple, and with a few unknown secrets, can be self maintained and driven often with much pleasure returned.

Absolutely correct! When I ordered my SWC in February '63 the options included KOs and L-76. As a 16-year old high school junior I had heard enough about the mysteries of FI that I decided to stay away from it. Not long after I was informed that my order would be delayed due to the fact that KOs had were not released for production, so I eliminated them from the order and saved $322. I could have used those funds to upgrade to FI, but decided not to for the above reasons.

When I received my '63 Corvette Shop Manual a month or two after taking deliver of the car I read it cover to cover. What amazed my was that the FI was just a mechanical implementation of Benoulli's equation that I had leaned about in high school physics class. The basic physics of the FI system are no more complicated than a carburetor. As said, it's not rocket science. Benoulli's equation had been around for at least 100 years at that time.

It's just a matter of keeping the mechanicals and adjustments in good working order, so one has to learn the idiosyncracies of the various FI systems including that cantakerous CSV. Keep everything clean and replace elastomers periodically and any car guy with the proper GM service documentation should be able to easily maintain an FI system once it's in proper working order.

Beyond that I have to say that the AFB is even simpler, and its only issue is the choke vacuum break piston getting sticky, so sometimes I say that not buying FI was the dumbest thing I ever did, but sometimes I think it was the smartest thing, too.

In a few faceoffs over the years from a rolling start, I never got beat by and FI car. Usually it was a dead heat.

The FI system has a much more efficient manifold architecture than any single carb OE manifold, but the Flint-machined heads are the choke point, so FI didn't really make much more power in OE form. But if you massage the heads, the FI really shines and will outperform any OE single carburetor manifold in the upper third of the rev range.

One exception is the 2x4 manifold on 283s. Once the heads are massaged the 2x4 will make more power in the upper 10-20 percent of the useable rev range, but FI makes more power below that very upper range due to the long runners, which give a very good inertia boost to the mid to low upper range torque, which means more power in that range.

Duke

[Gerald C.]

Re: C1 Fuel Injection Octane needs.

How does a 63 Fuelie react in the New England area on high octane pump gas? Also, who can test these units in the New England area?ThanksJerry

[Michael G.]

Re: C1 Fuel Injection Octane needs.

Jerry,

There are no definite rules and testing would do little to prove anything. Remember, all fuelies performed differently back in 1963 and the performance differences are greater now. You won't know how your 63 performs in New England, on New England fuel mixtures, until you drive that car, with that fuel, on a very hot day.

I can tell you that on very hot days its likely you will see some percolation with any 63 fuelie, with any fuel, in any geographic area. Whether that percolation is sufficient to make your car stall and see other significant performance issues depends largely on the car and the particular fuel used. If you see problems, you can prevent the worst of this by insulting your fuel lines and filter, from under the battery tray, all the way to the inlet of the FI unit. Additionally, a ceramic plate under the fuel unit (as shown in last quarter's Restorer), will help.

If you do both those things, you will cool the fuel sufficiently to prevent stalling and minimize idle fluctuation when hot, no matter what the fuel. Also, starting when hot will not be a problem.

With that said, what degree of percolation is left after insulation will depend largely on what fuel you use. As a rule, percolation will probably vary in this order: Most to least: E10 pump gas, non-ethanol pump gas (recreational), 100 LL aircraft fuel, 100-110 octane racing fuel.

There are, as stated below, (and more elegantly on Jerry Bramlettts' website), other reasons to preferably use use racing fuel in a fuelie.

[Domenic T.]

Re: C1 Fuel Injection Octane needs.

OK, I swore that I would never get into a post like this again but here go's.
I said that the higher octane fule burned slower than lower, I was wrong, they both burn at the same rate. The higher octane just starts it's burn LATER.
I can tune using the proper timing and I think that the proper timing keeps the geometry (piston push) on the crank better than tuning to use pump gass, and the cam timing is also happier.
I take my hat off to the guys that go to the trouble of feeding their cars the proper diet.
I have tried both fuels, pump gas & avgass in the same day and my rear tires tell me it's better. My guess is that the ones that dissagree have never tested both fuels in the same day or even tried it.
My compression is 11:something to 1 and those that have compression under 10:to1 may get away with pmp gas but I have only had multiple problems with our Kalifornia pump gas.
There are some that work the paper and do not do the practical test and condemn something that they never tried.
I am happy with my choice as it works for me and the other does not. I don't need a reason to lie about this as a few have insinuated that I am a liar or p-brain.
So I think the burn test thru the tubes with regular & premium gass back then was true in the fact that the regular made it thru faster. That's why they said higher octane burned slower and now the tests show that in fact they DO burn at the same rate, just one starts it's burn later (higher octane).

DOM

[Michael W.]

Re: C1 Fuel Injection Octane needs.

I said that the higher octane fule burned slower than lower, I was wrong, they both burn at the same rate. The higher octane just starts it's burn LATER.

Both start burning at the moment the plug fires.

[Domenic T.]

Re: C1 Fuel Injection Octane needs.

Mike,
If I were fishing I would know what post to use as you will dissagree with all I have done ort tested. Tell me this, have you ever used avgass? Never mind I think I know.
WRONG, Google fuel burn! you would dissagree with me even if I said your last name was Ward. It's on paper which seems to be what you are good at. I think That all that have low compression engines and/or have never tried it will dissagree and that's their loss..
WHY do aircraft engines @ any altitude REQUIRE higher octane? DETONATION!! Now look up the required fuel in aircraft? They let some with compression in the 6: & 7: range.
Seems that we are all supposed to be here to help, not practice politics.

DOM

[Michael W.]

Re: C1 Fuel Injection Octane needs.

Seems that we are all supposed to be here to help, not practice politics.

DOM

Nothing to do with politics. Your ongoing misunderstandings of detonation, combustion and the relationship with octane levels isn't helping anybody.

[Domenic T.]

Re: C1 Fuel Injection Octane needs.

Mike,
Thanks for the compliment, my ongoing missuderstanding of detonation, octane, and fuel in general has made some open minded people look at things differently and not believe everything they read, especially what the oil companies try to push down our
throats. The so called experts once said (from their desk) that a car could not go over 350 MPH, aircraft over 500, and the World is flat. The ones that couldn't read prooved that wrong.
By the way I also have NON FLAMIBLE racing fuel ( high octane) for the safety minded that are concerned about fires. Try it!

DOM

[Duke W.]

Re: C1 Fuel Injection Octane needs.

Both start burning at the moment the plug fires.

I think there is a slight lag before a flame kernel forms, but it's a matter of a few microseconds, and I believe it's about the same for a wide variety of typical hydrocarbon fuels. Typical spark duration for the Delco single point is 120 microseconds, 180 for the TI and HEI.

At 6000 revs one degree of crank rotation takes 27.8 microseconds, so the spark lasts for 5-6 degrees of crank rotation.

The range of ignition lag may be a factor in cyclic variation (variation in the indicator diagram from cycle to cycle), a phenomenom that is not well understood.

Duke

[Richard S.]

Re: C1 Fuel Injection Octane needs.

Regardless of the opinions stated, I ordered 54 gal. of 110 octane about 6 weeks ago and as soon as the ethanol cleared the fuel system the percolation problem stopped There is some additional expense however, I feel that it is worth the money and effort. I bought an electric pump and its about the same as going to the gas station except faster, 15 gallons per minute.

[Tom P.]

Re: C1 Fuel Injection Octane needs.

Well, I've read everything so far. I've tried to absorb as much as possible (that is, the stuff that makes sense), but with my own personal experience, it seems no matter what fuel is used, percolation is synonomus with underhood heat, period. Get rid of the underhood heat, the problems become non-existant.
How do you do that on a stock, FI Corvette with the hood closed? I don't know.
But in general, if an engine compartment is wide open to Mother Nature, there are virtually none of the typical hot engine/percolation problems.
The 56 has a SB400 with a modified Bill Thomas FI unit and in summer conditions, it has all the typical hot FI issues. As mentioned, once started and the clutch is out and the car is moving with the rpm's up, everything is fine (adding a 57 airbox helped some also).
And with the wide open engine/FI on the T-bucket, there are virtually ZERO issues with the FI because all that heat is quickly dissipated.