Any know if you can run av 105 octane in a 1988 328 with no cat?
There is no reason to. I would also be worried avgas does not meet some of the other motor fuel specs including the additive package required for motor fuel.
This would seem to be the best answer. But I'll ask anyway: what are you hoping the higher octane will do for you?
Been a couple decades since I asked that same question, but from my imperfect memory when I broached the same question of 110LL avgas, the specific gravity of the gas is incorrect for auto engines. Sounds a little silly, but I recall the suggested fix being some small amount of linseed oil as an additive. Again, long term memory and can't even be sure I had perfect information at the time. But I'm pretty sure it's a nono to run straight avgas. I'd suggest you ask a mod to move this to the aviation section.
FWIW I ran 100ll in a high compression big block Chevy years back without a problem. Things were a bunch more casual then, the FBO was happy to take my money 16 gallons worth at a time. No road tax paid on Avgas and the color supposedly indicates this. In today's litigious world your FBO might balk. The miffed Cessna pilots waiting to refuel often warned me that it would hurt my engine. I beat the living daylights out of that thing and it loved it. I've seen 100% gasoline(if that is your goal) in rural areas. Those farmers know better than to put corn squeezins in their own machines.
I ran AVGAS in my chipped 1986 Porsche 944 Turbo with Bosch Motronic EFI and a CAT bypass. I wanted the higher octane for running higher boost during autocrosses. Never had a problem. 1980s vintage EFIs weren't so sophisticated back then.
While I remember the issue, I don't exactly remember why it was a problem. Perhaps it's an issue of long, long term damage that doesn't ever manifest in the lesser mileage we put on our toys.
I think there are a few reasons you don't want to run 110LL gas in your car: 1)It'll kill your catalytic converters. Even LL has more lead than your cats like. 2) Piper's memory is good here: the specific gravity of 110LL is lower (~.70) than typical pump gas (.72 - .77). This may interfere with fuel metering, so you may wind up inadvertently running leaner than planned. Further, the speed at which the fuel burns -- a imprecise/bad term -- will typically be higher with lower SG fuels. To benefit from this, you'd need extra advance in the ignition timing -- which your car likely doesn't have. 3) If (and this is a big IF) your FBO will sell it to you, the Feds will love tagging both him and you with hefty fines. No road taxes figured into the price. To get back to the OP -- if you're running a car with ridiculous boost and want to prevent detonation you're better off going with either race gas or the old trick popular with some of the turbo monsters of the '70s: putting toluene (110 octane) in the gas.
If your engine is running stock compression ratio, there is absolutely NO advantage in using higher octane gas than your engine requires for maximum power output. Wasted money, especially in today's world with 100LL aviation gas running between $6 and $9 per gallon. By the way, the color (blue) indicates that it is 100LL, not 80 (red) or 100 (green). It has absolutely nothing to do with road tax. High octane gas does not have any more energy in it than regular gas. Octane only measures resistance to detonation.
Avgas (the most common flavor known as 100LL) will run fine in older low compression V8s that can handle the lead. The combination of high octane and lead suppress detonation which is/can be a problem on aircraft engines. In a modern (remember, most piston aircraft engines are 1950s technology) automobile engine, the lead causes more issues than the high octane rating solves. I run a chain of FBOs and I can tell you that the number of folks buying 5 gallon cans of Avgas has dwindled to virtually zero. The specialty 'pump gas' that's available is much better for this purpose.
I believe the octane rating is different for aircraft and 100LL may not be equivalent to 100 octane rating for a car. Whenever we run 100LL in our tugs they seem to run hotter. If you really want to go nuts you could buy 145 or 150 octane (can't remember exactly) that they use at the Reno Races. Somewhere I remember reading that 100LL was actually less octane then current car premium. But you are guaranteed no ethanol it really harms aircraft fuel systems.
It's been a while, 25 years or so, but if my memory serves me correct there are some issues with running the AV gas. At the time I was involved with a drag boat operation, which ran a normally aspirated 900hp 500 inch Chevy. The static compression ratio was close to 15:1. We ran Cam2 racing gasoline for fuel. Our 45 gallon drum ran dry and we couldn't get another in time for the weekend. We picked up some AV gas to get by. It was no where as good, the octane just wasn't good enough for us. But there were guys that ran it, and I seem to remember they complained because they couldn't get a good plug reading with the stuff.
Jumping in a bit late, but IMHO, no reason to use AV gas in a 328. My '86 runs just fine on 93 octane (or more often 91 octane) right out of the pump, and if you have upgraded your hoses to modern hose, which should be done anyway for safety, the ethanol in modern gas should not be a problem. That's my $.02. YMMV, but that's how I see it.
So this 328 has no cats-but does the ethanol gum up older fuel injection systems/or newer ones for that matter? I know about the issues with old gas lines
I ran 110 AVGas in a 66 Vette in the 60's but wouldn't run in in my Ferraris today Sent from my iPhone using Tapatalk
A buddy use to use it in as a blend with reg gasoline his Twincam Lotus engine when lead was being taken out of gasoline - had no hardened valve seats.
Why not just use high octane car fuel? We have 99 octane fuel available at the pump in the UK. Putting higher octane fuel in a car does not yeild any performance benifits, unless the car is designed to run on high octane fuel. An example would be my F10 M5, it's quoted BHP figured is based on 98 octane fuel, it is designed to run on 98 octane fuel, running on a lesser octane fuel will lower the BHP, but not by much. Cars tend to be build to accept a wide range of octane levels, so unless you remap the ECU and start changing your engine it's a waste of money. Neil
91 no etoh available at many marinas and stations. Also 100 with 9% etoh at some stations. I use a mix. Or just 93 if that'S all there is. GTS Bruce
