100LL AV gas in my 928 good or bad idea
10-28-2008, 09:29 PM
#1
Instructor
Thread Starter
Join Date: Aug 2008
Location: Rhode Island
Posts: 209
Likes: 0
Received 0 Likes
on
0 Posts
100LL AV gas in my 928 good or bad idea
every time i watch the ground ops people fill up my 172 i always wonder if 100LL would screw up my 928 i have no cats or o2 sensor??? if i were to use it would i notice aney preformance gains??
10-28-2008, 11:00 PM
#2
Team Owner
seems Tim Dey uses a higher octane for his Stroker, maybe 105, race fuel , and im not sure where he gets it , possibly a performance shop
I Put some av gas in the Moto Guzzi and it seemd to like it but it did leave more deposits on the spark plugs so it would stand to reason it would do the same for the combustion chamber.
Dont get caought it could be a big fine, however they might fill up a few 5 gallon cans for you
I Put some av gas in the Moto Guzzi and it seemd to like it but it did leave more deposits on the spark plugs so it would stand to reason it would do the same for the combustion chamber.
Dont get caought it could be a big fine, however they might fill up a few 5 gallon cans for you
10-28-2008, 11:45 PM
#5
Nordschleife Master
Should not be any problem as long as you don't have cats or an O2 sensor...though I don't think it is a big problem for an O2 sensor that is not being used... :-)
As for burning the valves...I doubt it. Octane is a burn inhibitor. It does not make the explosion in the chamber hotter, in fact it delay's the burn or makes it harder to ignite in any event. That is why HIGH COMPRESSION motors (ie. race motors, highly boosted motors etc.) NEED the extra octane. Otherwise the air fuel mixture would explode to EARLY in the combustion cycle and cause the engine to fail.
The 100LL would smell MUCH better than regular fuel though! Not as sweet as race gas, but much better than pump gas! That might be reason enough to use it right there! Though at $4+/gal I can't imagine that...we are getting close to $2/gal here in Austin...
As for burning the valves...I doubt it. Octane is a burn inhibitor. It does not make the explosion in the chamber hotter, in fact it delay's the burn or makes it harder to ignite in any event. That is why HIGH COMPRESSION motors (ie. race motors, highly boosted motors etc.) NEED the extra octane. Otherwise the air fuel mixture would explode to EARLY in the combustion cycle and cause the engine to fail.
The 100LL would smell MUCH better than regular fuel though! Not as sweet as race gas, but much better than pump gas! That might be reason enough to use it right there! Though at $4+/gal I can't imagine that...we are getting close to $2/gal here in Austin...
10-29-2008, 12:29 AM
#6
Drifting
I run race gas in my one of my other cars. That engine is holding together fine. I add about 5 degrees advance when it's in the tank. No burnt valves, or cracked pistons. Just a white tailpipe...
10-29-2008, 12:47 AM
#7
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
The previous owner of my 79 ran 110 leaded race fuel at the track.
Trending Topics
10-29-2008, 01:09 AM
#8
Shameful Thread Killer
Rennlist Member
Rennlist Member
Your car will run worse generally, and the fuel consumption will increase. The flame front is slower, and it could burn exhaust valves in some cases. Lead deposits will form in the well of the plugs, but can be cleaned with a dental pick.
10-29-2008, 01:57 AM
#9
Race Director
as long as its unleaded it should be fine......I've used 100 octane unleaded in my M3 at the track before....but 928's aren't designed for it....so why spend the money unless you have a custom motor that requires it.....
10-29-2008, 02:34 AM
#10
Shameful Thread Killer
Rennlist Member
Rennlist Member
[QUOTE=IcemanG17;5945670]as long as its unleaded it should be fine....QUOTE]
100LL is leaded fuel. That's what the "LL" means. And sadly, it's almost gone. There are only two refineries willing to make it anymore because it contaminates the trucks and final refining stages. Depending on the coming political climate, we may be switching to an unleaded fuel soon. Many aircraft are going to suffer from worse performance, and need adjustments to carbs, FI, and ignition. These changes are not trivial in the aviation community.
A car can be adjusted to run on 100LL. However, at RPM above about 3000, the flame front will continue to burn after the exhaust valve is open, and the valve will burn.
100LL is leaded fuel. That's what the "LL" means. And sadly, it's almost gone. There are only two refineries willing to make it anymore because it contaminates the trucks and final refining stages. Depending on the coming political climate, we may be switching to an unleaded fuel soon. Many aircraft are going to suffer from worse performance, and need adjustments to carbs, FI, and ignition. These changes are not trivial in the aviation community.
A car can be adjusted to run on 100LL. However, at RPM above about 3000, the flame front will continue to burn after the exhaust valve is open, and the valve will burn.
10-29-2008, 03:12 AM
#11
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
[QUOTE=docmirror;5945726]
What Doc said. Avgas has no place in your car engine. I will say this though, nothing like the smell of 100LL on a cold start in the morning.
as long as its unleaded it should be fine....QUOTE]
100LL is leaded fuel. That's what the "LL" means. And sadly, it's almost gone. There are only two refineries willing to make it anymore because it contaminates the trucks and final refining stages. Depending on the coming political climate, we may be switching to an unleaded fuel soon. Many aircraft are going to suffer from worse performance, and need adjustments to carbs, FI, and ignition. These changes are not trivial in the aviation community.
A car can be adjusted to run on 100LL. However, at RPM above about 3000, the flame front will continue to burn after the exhaust valve is open, and the valve will burn.
100LL is leaded fuel. That's what the "LL" means. And sadly, it's almost gone. There are only two refineries willing to make it anymore because it contaminates the trucks and final refining stages. Depending on the coming political climate, we may be switching to an unleaded fuel soon. Many aircraft are going to suffer from worse performance, and need adjustments to carbs, FI, and ignition. These changes are not trivial in the aviation community.
A car can be adjusted to run on 100LL. However, at RPM above about 3000, the flame front will continue to burn after the exhaust valve is open, and the valve will burn.
What Doc said. Avgas has no place in your car engine. I will say this though, nothing like the smell of 100LL on a cold start in the morning.
10-29-2008, 04:57 AM
#12
Burning Brakes
NO av gas in high performance engines it will burn the exhaust valves my boss put it in his FZ400 it is now toast av gas is for low horsepower low compression motors its made for coating the insides of the airplane motors for longer life ie safer it has no place in anything high performance
paul with 4 79 928s
paul with 4 79 928s
10-29-2008, 08:34 AM
#13
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
I guess I need to check by valves.
10-29-2008, 10:41 AM
#15
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Sorry, forgot the sarcastic smiley. My 79 has been a dedicated track car for at least 15 years. Most of those run with leaded race gas (I don't use it, I've only had the car for three years).
Heads have never been removed. I personally know all but the first owner. Well, I know of him since he founded the hardware store chain Menards.
It dyno'd 40rwhp under a stock S4. I would say that's pretty healthy for a stock 79 with only exhaust work.
Heads have never been removed. I personally know all but the first owner. Well, I know of him since he founded the hardware store chain Menards.
It dyno'd 40rwhp under a stock S4. I would say that's pretty healthy for a stock 79 with only exhaust work.
