AVGAS

[matt dunn]

A car that does not need the extra octane to prevent detonation will usually make more power on 98
as 98 burns faster than avgas and there is a long technical explanation why.


I run Avgas as I get it easier and cheaper then 98.

What about a car that wants to run a psi or two higher??? And also 98 mixed with avgas lets say 60 percent 98 an 40 percent avgas, will it be 107 octane still or less like 101 or sumthing???

If a car has no knock sensor capability like most aftermarket ecu's
then it will not make more power not matter what,
only has the possibility of loosing power.

As for running a psi or 2 higher, I'd be more worried about the amount of fuel it will inject rather than the type.
If the tune is that close that it will need avgas witn 2 psi extra,
then run it.


You may find that with 2 psi extra and avgas, you are not making any more than on less boost with 98.


but it wont hurt it unless it has a cat or an o2 sensor


I'm not a fan of mixing fuel as I dont believe it's a good way of altering octane, you may get one injection of one octane and one of another,
and you have no idea of what you will end up with.

[Lith]

I was under the impression aviation fuel is dyed different colours to identify which grade it is, is this true?

[matt dunn]

I was under the impression aviation fuel is dyed different colours to identify which grade it is, is this true?

All the avgas I've ever seen is green.


Race fuel may be different, but still the same fuel,

but mine is direct from a pump at the airport.


FYI, Avgas is a road car is illegal.

[Akane]

AVgas in green, seen too many green stains from plane aerofoils due to spilling.

Does the AV gas's flame front burn / spread across slower than 98?

with avgas you can run leaner, so it doesn't suddenly turn a burning flame front into an explosion, ie: detonation, if I remember correctly.

[Lith]

All the avgas I've ever seen is green.

Race fuel may be different, but still the same fuel,

but mine is direct from a pump at the airport.

FYI, Avgas is a road car is illegal.

Cheers, I was pretty sure that was that case - Avinesh, as I said last night... work out what that fuel is before you put it in your car. If its not pump gas, and not race fuel, but not clear then its something else again

Could be Jet fuel, in which case you may as well put diesel in there

[fivebob]

I was under the impression aviation fuel is dyed different colours to identify which grade it is, is this true?

Low Lead (100LL) is coloued blue, normal Avgas is coloured green.

[Lith]

See above comment to understand why I said that, I was pretty sure the case is as you described but given I'm not an expect I didn't want to jump the gun when he told me the "AVGAS" he has is clear....

[fivebob]

I didn't want to jump the gun when he told me the "AVGAS" he has is clear....

If it's clear then it's Jet-A1, otherwise known as Kerosine

[RedMist]

Avgas does have a slower flame front, hence it's higher octane.

It also has a very light top end. It'll evaporate quickly leaving the heavier, low octane base. I dump my race gas, in sealed containers, if it's over two months old and never run the standing gas in the tank (as it's open air). I'll never run avgas supplied from anywhere other than an airport pump, it's just not worth blowing an engine over.

[Crampy]

I didn't want to jump the gun when he told me the "AVGAS" he has is clear....

If it's clear then it's Jet-A1, otherwise known as Kerosine

Or AVTUR.
Will run in a diesel car.
Not so good in a petrol.

[Crampy]

Just run with a nice fresh batch of 98. The car is tuned for it, so run it as it's tuned.
If you want to run more boost, tune it for more boost, or check it out first at least (wide band).

[Lith]

Or AVTUR.
Will run in a diesel car.
Not so good in a petrol.

Yep - in which case Avinesh, DON'T run it.... not only will it not be an improvement over petrol.... fairly good chance it WILL actually damage your engine.

[Mr Revhead]

if it runs!

[Lith]

Haha yeah well there will probably be enough fuel in the lines to get it started long enough to get the jet fuel in there - hydraulic you reckon?

[sergei]

Haha yeah well there will probably be enough fuel in the lines to get it started long enough to get the jet fuel in there - hydraulic you reckon?

Nah will not hydraulic, when I worked in car yard, plenty of moron/car groomers put diesel in petrol cars, all it resulted either not running at all or car turning into smoke machine and bill of flushing tank/replacing fuel filter.

With jet fuel you might get good results if your car is diesel .

[Mr Revhead]

Yeah I would expect it to stop!
May want to check your tune if it hydraulics

[fivebob]

Probably keep running but not very well and not be able to shut it off.

I knew a guy who's father couldn't by enough petrol in WWII due to the rationing. He told us that he used to start his bike on petrol, then switch to kerosine for the trip to work, and turn the fuel tap off a minute or so before he arrived at his destination. Then, when it stopped, he'd connect the bottle of petrol he had up to the carb and fill the float bowl up for the return trip. He reckoned it ran ok, had no power and you couldn't turn it off with the ignition, just had to wait till the carb ran dry

Then again that was a 1940's engine that only usually ran on 82 octane petrol so I don't know how a modern engine would react.

[iOnic]

Run it on the fuel it's tuned for. If you want more boost - tune it for more boost. If you don't think your current tune is safe on the limit, get it retuned or turn the boost down while on the strip. If your tune is shit, running avgas isn't going to help that fact. If your tune is good, you'll get your best results on the fuel it was tuned on...

[avinesh]

Was avgas car ran ok did have a little missfire at times but i only put a small amount in still managed to run a 11.7 but recon would have done better on 98 ......biggest issue was me not being able to get forth properly getting a little scared on the mickey thompsons or would have had a low 11 for sure in the last run where i completely didnt hit 4th ran a 11.7 with a very low trap speed of 170ish (didnt hit 4th)

[Bling]

recon would have done better on 98

Next time you'll take peoples advice on board then aye?