fuel Injection fuel question---again!

[Gerald C.]

Need more advice on my 63 Fuelie. There is a station near me that sells ethanol free gas with 96 or 108 octane. Should I consider this or the VR 110 Racing fuel.

OR, I could have the car "tuned" to pump gas. The only problem here is that I'm told that they will have to drill a small hole in the exhaust pipe to set the air/fuel mixture. This is the part I dislike because my car is just finished being restored!

Thoughts?

[Ed S.]

Re: fuel Injection fuel question---again!

Gerald,
I assume your engine is stock. FYI, I have a 64 365 hp L76, I use 93 non-alcohol exclusively and have absolutely no problems at all. Did have percolation issues with ethanol 93. I also wired my heat riser wide open. If you can get 96 octane I think you will be fine. I think that is higher than what was originally recommended by the General although I also believe the way octane is measured or rated has changed since 1963.

[Michael W.]

Re: fuel Injection fuel question---again!

I also believe the way octane is measured or rated has changed since 1963.

You're right, the rating system changed in the mid-70s. Today's 93 would have been rated at about 97 in the old system.

[Don H.]

Re: fuel Injection fuel question---again!

Gerald,

I have run aviation fuel in my older fuel car for over 30 years and it works great, John D will agree. The problems with that is you have to know how to secure it at a local airport in gas cans. Obviously that is not possible when you are traveling so then the highest octane pure gas you can find is your best option. I have been "playing" with a 7017375 unit on a coupe with AC & auto for over four years now trying to make it road worthy for the NCRS road tours. That means running in mid to late July on pump gas. I am finally having good success this year and I know others who have done it. Good luck, Don H.

[Richard S.]

Re: fuel Injection fuel question---again!

Two years ago I Tim Mickey tuned my 60' FI to run on pump gas however, he told me that his 58' did not like ethanol when he went on long trips. To date I have only used VP-110 and even carry extra on longer trips. I do not have percolation in hot weather like I did with pump gas.

[Joe L.]

Re: fuel Injection fuel question---again!

Need more advice on my 63 Fuelie. There is a station near me that sells ethanol free gas with 96 or 108 octane. Should I consider this or the VR 110 Racing fuel.

OR, I could have the car "tuned" to pump gas. The only problem here is that I'm told that they will have to drill a small hole in the exhaust pipe to set the air/fuel mixture. This is the part I dislike because my car is just finished being restored!

Thoughts?

Gerald------

Your engine should run on pump 93 octane or, even, 91 octane if that's the highest generally available in your area.

If I had a car that would not run on easily available pump gas, I'd de-tune it or, even, modify it so that it would run on pump gas. Having to be "tethered" to a source of racing fuel, aviation fuel, etc., is not for me. It's not what I call freedom.

[John D.]

Re: fuel Injection fuel question---again!

Not exactly on target here with the question but let me tell you a story.
As usual Corvette Carlisle was very hot. That's expected as it's late August.
My vendor trailer has a generator. When I run ethanol in the generator and it runs out of wonderful ethanol it refuses to easily start again.
Meanwhile I am dying in my trailer. Friends changing spark plugs, etc trying to get it running again.

Three years ago I switched to using 100LL AV fuel. My son said to me that we used more fuel this show than others because it was in the high 90's some of the time. When the thirsty generator ran out fo 100LL he carefully filled it up again. Yes I know you are not supposed to do that but we did it. The generator started on first pull and ran perfect the entire show.
Try that with ethanol. Never happen.
I even carry a spare generator just in case this old Honda fails
I am responsible for talking all the suppliers or FI parts into upgrading the rebuild kits, etc for ethanol.
Here's how that happened. Coming home from a BG show in 1990 I stopped at a Speedway station on the border of Indiana and ILL.
Bought a one gallon can and gallon of 10% ethanol. Brought it to my shop and tested the various o'rings, seals, etc with it. Everything failed.

So I kept this in mind for many years. Now we are in good shape for at least making the fuel injection run on ethanol but if it's hot like this past weekend you had better not be in bumper to bumper traffic or forget it. John

[Duke W.]

Re: fuel Injection fuel question---again!

Need more advice on my 63 Fuelie. There is a station near me that sells ethanol free gas with 96 or 108 octane. Should I consider this or the VR 110 Racing fuel.

OR, I could have the car "tuned" to pump gas. The only problem here is that I'm told that they will have to drill a small hole in the exhaust pipe to set the air/fuel mixture. This is the part I dislike because my car is just finished being restored!

Thoughts?

There are four different ways to measure octane. So which ones are we dealing with here?

There are two issues that can arise when using modern E10 gasoline in a vintage car - detonation and percolation/vapor lock.

Detonation may arise because the actual compression ratio is higher than the engine can tolerate with available pump gas. This is easily determined by testing - load up a fully warmed up engine at low revs by accelerating at half to WOT from 1000 to 3000 revs in third or fourth gear. It's best if you do this on an upgrade on a hot day. If sustained detonation is apparent, changes can be made to the spark advance map, but the OE map is very lazy, so '63 SHP/FI engines will usually operate on detonation-free on available pump premium. A little transient detonation when you first open the throttle is okay as long as it doesn't last more than about a second.

As originally configured in '62 Chevrolet got a lot of 340/360 HP customer detonation complaints back when they were new. Chevrolet's solution was to install two head gaskets on each side beginning mid-'62 production, and this continued through the end of '63. The extra .018" shim gasket dropped the as-built CR about about 0.6, and this successfully addressed the detonation complaints.

You can measure the thickness of your head gasket(s) with feeler gages at the corners of the head block interface.

Do you know what pistons are installed? Many vintage Corvette engines were rebuilt over the years with "low compression" pistons and thick head gaskets, so the actual CR may only be between 8 and 9. Most guys have no idea what the actual CR of their engine is unless they know all the parts and specs and took all the measurements to compute actual CR, documented that data and passed it on to subsequent owners. Some will operate detonation-free on modern 87 PON fuel because the CR is so low.

If the FI system is set up to run well on non-ethanol fuel it should run okay on E10. There is absolutely no need to "drill holes" in the exhaust system. If you want to check the A/F ratio under various operating conditions, you can have it done on a chassis dyno with a wide band O2 sensor inserted into the tail pipe. You should disassociate yourself with whoever told you that holes need to be drilled in the exhaust system.

Percolation problems have been discussed many times, and a good solution is to insulate the fuel pipe that runs along the frame in the engine compartment. Some also insulate the pipes beyond the fuel pump. It doesn't look pretty, but many have reported bowl temperature drops of 20-30 degrees, which dispatches the percolation problem.

Searching will reveal several threads with photos and comparative temperature measurements.

Duke

[Michael J.]

Re: fuel Injection fuel question---again!

There are four different ways to measure octane. So which ones are we dealing with here?

There are two issues that can arise when using modern E10 gasoline in a vintage car - detonation and percolation/vapor lock.

Detonation may arise because the actual compression ratio is higher than the engine can tolerate with available pump gas. This is easily determined by testing - load up a fully warmed up engine at low revs by accelerating at half to WOT from 1000 to 3000 revs in third or fourth gear. It's best if you do this on an upgrade on a hot day. If sustained detonation is apparent, changes can be made to the spark advance map, but the OE map is very lazy, so '63 SHP/FI engines will usually operate on detonation-free on available pump premium. A little transient detonation when you first open the throttle is okay as long as it doesn't last more than about a second.

As originally configured in '62 Chevrolet got a lot of 340/360 HP customer detonation complaints back when they were new. Chevrolet's solution was to install two head gaskets on each side, and this continued through the end of '63. The extra .018" shim gasket dropped the as-built CR about about 0.6, and this successfully addressed the detonation complaints.

You can measure the thickness of your head gasket(s) with feeler gages at the corners of the head block interface.

Do you know what pistons are installed? Many vintage Corvette engines were rebuilt over the years with "low compression" pistons and thick head gaskets, so the actual CR may only be between 8 and 9. Most guys have no idea what the actual CR of their engine is unless they know all the parts and specs and took all the measurements to compute actual CR, documented that data and passed it on to subsequent owenrs. Some will operate on modern 87 PON fuel because the CR is so low.

If the FI system is set up to run well on non-ethanol fuel is should run okay on E10. There is absolutely no need to "drill holes" in the exhaust system. If you want to check the A/F ratio under various operating conditions, you can have it done on a chassis dyno with a wide band O2 sensor inserted into the tail pipe. You should disassociate yourself with whoever told you that holes need to be drilled in the exhaust system.

Percolation problems have been discussed many times, and a good solution is to insulate the fuel pipe that runs along the frame in the engine compartment. Some also insulate the pipes beyond the fuel pump. It doesn't look pretty, but many have reported bowl temperature drops of 20-30 degrees, which dispatches the percolation problem.

Searching will reveal several threads with photos and comparative temperature measurements.

Duke

+1 to all that, been there done that too.

[Michael W.]

Re: fuel Injection fuel question---again!

My vendor trailer has a generator. When I run ethanol in the generator and it runs out of wonderful ethanol it refuses to easily start again.

You've been complaining about that useless generator for close to ten years. Time for a new one? Look at the money you'll save on fuel.

[John D.]

Re: fuel Injection fuel question---again!

You've been complaining about that useless generator for close to ten years. Time for a new one? Look at the money you'll save on fuel.

Bought a new generator. Old one doing just fine and is reliable. It's the ethanol that was killing the old generator. Just like it does our Carbs and Fi units.