2110 HP and AvGas?

[t30mg]

I recently bought a seat sand rail and seller built the engine and runs 50% Race Gas. I'm at the airport often enough so I prefer AvGas when I need more stable fuel than pump gas can provide. Anyone else run Av in their VW's?

What he told me about the engine: 2110, 40mm Del Carbs, W130 cam, bronze lifter bores, 37.5 x 40 valves, timing approx 34 BTDC and straight cut gears.

Does this sound like a good setup and what would a realistic Horse Power be for it?

It's compression is high and it's hard to crank through it when cold. I retarded the timing a little, and then alot, and the starter still struggles to power through the compression until the engine is warmed up. Had 2 different stores test the battery and both said it's perfectly good...?

[UK Luke 72]

The volt drop through your ignition key can cause starting issues.
As can bad earth straps.
WOSP do a brilliant starter that doesn't even flinch at my 11:1 2276
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[slalombuggy]

Check your starter bushing and all the connections for the starter including the ground.

Once I got over 10:1, my factory starters struggled, especially when hot. I bought an IMI gear reduction starter, and even at 13:1, never had cranking issues.

[madmike]

Unless u can adjust the fuel mixture on the fly ? I would Not use Avgas! Planes can do this, Research & Learn I was a VP Race Fuel dealer at one time,learned about that stuff
_________________
'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[Wulfthang]

Aviation fuel contains deicers and other additives that "ground based" vehicles don't use. Some of them can cause problems like eating your fuel system parts. Plus, aviation fuel uses a different octane rating system than auto fuels. 110 octane aviation fuel is not the same as 110 octane auto fuel.

The worst part though, is that you may be hurting your performance by using an octane rating higher than what you need. A high octane fuel resists knocking because it's slower to ignite. The flame front is not as erratic and is smoother which produces more horsepower than if it were popping all over the place.

If your engine doesn't knock, don't use a higher octane fuel. It burns slower which means less horsepower.

I met a guy one time who insisted that his engine was built so incredibly powerful and hostile, that he had to burn jet fuel in it! He got angry when I laughed at him!

[oprn]

Well guess what! Deicer is simply alcohol!! Funny thing is the aviation guys don’t recommend using car fuel in aircraft even though some of their engines are rated for it because the alcohol in it ruins the rubber parts in their carbs!

Yes you will get less power and mileage in an engine using an octane rating higher than it is built for.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[Dusty1]

We used to fly into a hillbilly airport Saturday afternoons. The local Modified heroes would line up to fill their race cars with 100 low lead. Same cars were consistent winners at Albany / Saratoga, Lebanon Valley and Fonda.

Same drivers, same tracks, different cars typically Bicknell modifieds, now. They're still winners.


Our airport used to have a DC-3 tied down out back, a ghost of the Congo wars. Its log book was a mess and its Pratt & Whitney radial engines were far beyond TBO. Story goes since the mid- 1960s every time a conflict lit up in Africa they would fly it across a couple borders and find someplace safe to tie it down for a few years. This went on for decades until someone re- traced the old WWII bomber transport route back to a few miles south of Pratt & Whitney.


Seems to me a Pratt & Whitney radial is just a different arrangement of VW cylinders.

.
.

[Shane Tuttle]

Used 100LL in my bug when I was going to A&P school in Colorado. Worked at an FBO and had access to some when we defueled aircraft and the customer didn't want it put back in. Filtered it and it ran fine. I commuted between Broomfield and Lakewood. If memory serves, about 10k miles worth of fuel was used. I cracked open the case a few years later and found no discernable lead buildup or wear beyond normal. Never ate anything in my fuel lines or carbs.

However, I wouldn't start using it in yours until you figure out what's going on with your other problems.

[94touring]

[DeathBySnuSnu]

Well ...... I am old and never ran AV gas in my VW as it was fine with pump premium.

As a youngster in the later 70's to the early 80's we did a lot of street drag racing. All the winners ran a concoction of fuels. Leaded premium mixed with AV gas and a fuel booster additive from the parts store. Everyone swore by it.....I even mixed a lot of it myself for V-8's.
So when I finished high school and had some time I started racing the south eastern motocross circuit.
Side note.....I was a motorcycle guy....was a wrench at the Honda dealer from 15 untill I went to live in a dorm.

So I was at a major race event and tech was more serious than I expected. Fuel was supposed to be pump and I was sitting there with a bike 10cc over max and with the fuel concoction. Luckily they did not check displacement but did take a fuel sample.......and it easily passed tech.....I was amazed......and lost any belief in using AV gas in anything that don't need the anti-icing property it has.

After this point if I wanted certain fuel properties I bought race gas, nitro methane, alcohol, by the drum.

Bottom line.....
Big NO on the AV gas.
For a street engine....build it for today's premium.....or build it for E-85
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[Triumph]

Years ago I had a conversation with an engineer from Union 76 regarding 100 LL AvGas in race engines. He stated that 100LL formulation is "lighter", i.e., less dense, than regular gas. This means that without adjusting your mixture, you're going to run about 7% leaner with 100LL which can lead to burned pistons etc. By richening the mixture, I was able to bring it in balance with no issues in a race engine. That said, as the engine was tuned to develop more power, it needed a higher octane. At that point I switched to race gas and re-adjusted my mixture.

As you can tell from the comments, there are a lot of factors at play; among them the fact that 100LL is low-lead, not unleaded. So if you have to be concerned with emissions and catalytic converters, that will play in.

It may help to associate octane with the point at which uncontrolled ignition (knock) occurs and BTUs as the available energy in the fuel.

100LL is 5.91 lbs/gal
91 Unleaded is 6.35 lbs/gal

[94touring]

Both 100ll and pump gas should weigh in at 6.1lbs at 15C. I never saw a difference in air fuel ratios on my wideband going from 100ll to 93 back when I'd run it. At least not that I recall.

[Agavelouis]

[94touring]

Agavelouis is spot on. I flew lean of peak everywhere in piston airplanes. Ideally you guys tune your Vw's at light cruise for lean of peak as well. One other benefit of 100ll is it doesn't go bad as quickly as pump gas.

[modok]

should crank easy with that cam.
Starter weak, or something is tight, compression is way higher, or the cam is much shorter than you were told.

[ccowx]

I have struggled with detonation in a V8 car that I also own. I have been given avgas by aviation mechanic buddies. Due to specific gravity issues mentioned here, it doesn't meter precisely the same through a carb, so I mixed it 50/50 with 94 octane non-ethanol pump premium. Never had an issue and ran great.

Chris

[Wulfthang]

Yeah, I knew guys that swore by it back in the day but I never used it. We ran a custom mix of Sunoco 260 (From the pump!), upper cylinder lubricant and whatever octane booster was on sale. That mix also worked pretty well for Nitrous boosted systems. Course, this was on motorcycles and all of the car guys I knew, ran Alcohol. (I love the smell of Nitro!)

[oprn]

If there is any fuel surrounded by more myths, old wives' tale or just plain whoppers than avgas I am unaware of it!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[madmike]

Avgas is made so inconsistent, Tell me Every made batch is the same.
go ahead and use it ,, not my motor
_________________
'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[Paul Jr]

My issues with hard cranking on a bigger engine went like this.

Replaced and cleaned grounds, engine cranked a little better but still hard.

Replaced starter bushing, engine cranked still slow and hard but started.

Sat and thought why? Then looked at engine run stand and saw the starter on it was from an automatic. Also looked and realized every other VW beetle based vehicle here has an automatic starter or an aftermarket high torque starter.

Went and got a rebuilt automatic starter from the local auto parts store, it fires one hit everytime now.

For comparison it’s a 2275 with 12:1 compression