Avgas?

[sharky]

G'day, I'm thinking about trying Avgas in my ZXR400. Have been trying to do a bit of research about it but have been finding contradicting answers. Would it make much difference/cause damage etc. Engine is standard (as far as I know)? Or should I just stick with pump gas? Anyone run it in a similar bike?
Cheers.

[rustys]

Sharky, I race the same bike 1989 model, with stock engine. Have run 50/50 mix of 91 and avgas in the past, but never found any noticable difference. So to save the hassles i just stick to 91. Others may have a different view, cheers.

[Skunk]

If the engine is std you're best with the octane rating it was designed for. Avgas is a slower burning fuel that's only any better in high compression engines. As it burns slower it's more resistant to denotation. I use it in my Bucket as it runs 15:1 compression and I was told to by the expert that built it.

[svr]

You run the minumum octane your engine can run on without detonating (pre-igniting, pinking). It's not a nice noise and is hard to miss. If it's not doing this you're fine with 91 I guess.
Time for some compression work would be my advice!

[t3mp0r4ry nzr]

engine may run a little cooler so there may be reduction in friction, but there would be no seat of the pants difference in power.

AVgas also spoils quicker than pump-gas.

Also, under F3 regulations, avgas is prohibited. pump gas is the only option with a 98 RON as max octane rating allowable (it was good to see MNZ testing the gas of the top-runners at puke in the F3 class).

I wouldnt bother myself. The only reason to run it is for safety. But if jetting is lean, put bigger jets in. If running hot, get cooling fixed or improved.

fair question tho :)

[GSVR]

You run the minumum octane your engine can run on without detonating (pre-igniting, pinking). It's not a nice noise and is hard to miss. If it's not doing this you're fine with 91 I guess.
Time for some compression work would be my advice!

Yes this would be a good way of weeding out worked engines in a Production Class. EG Standard SVs run fine on 91 so supply everyone with 91 enforce its use and if their bike don't run on it bang.

[SARGE]

If the engine is std you're best with the octane rating it was designed for. Avgas is a slower burning fuel that's only any better in high compression engines. As it burns slower it's more resistant to denotation.

chuck a bit of Acetone to it though and that sorts it out though


but yea .. save your money unless its modded with high compression

[GSVR]

Also, under F3 regulations, avgas is prohibited. pump gas is the only option with a 98 RON as max octane rating allowable (it was good to see MNZ testing the gas of the top-runners at puke in the F3 class).


So you haven't read or understand the rules. This is pretty typical of most F3 riders so don't feel bad.

[t3mp0r4ry nzr]

So you haven't read or understand the rules. This is pretty typical of most F3 riders so don't feel bad.

How about you enlighten us idiots then - oh wise one - instead of insulting over the internet

[GSVR]

How about you enlighten us idiots then - oh wise one - instead of insulting over the internet

Why don't you read your rulebook! Hell I may be wrong I have been in the past.

Sorry you took it as an insult. I did say don't feel bad... As for insults I'm insulted that you are insulted by the fact I'm pointing out to you that you can run avgas.

[codgyoleracer]

G'day, I'm thinking about trying Avgas in my ZXR400. Have been trying to do a bit of research about it but have been finding contradicting answers. Would it make much difference/cause damage etc. Engine is standard (as far as I know)? Or should I just stick with pump gas? Anyone run it in a similar bike?
Cheers.

With compression (higher) & ignition changes you might see a gain (but it will be small). It mainly provides a bit more detonation protection.
Running AVGAS is legal - running highly oxygenated fuels I.E ELF racegas style - is not legal.

[t3mp0r4ry nzr]

Sorry you took it as an insult. I did say don't feel bad... As for insults I'm insulted that you are insulted by the fact I'm pointing out to you that you can run avgas.

My bad, was thinking of pro-twins fuel regs.

To be fair though, you didnt say that you couldnt run avgas, you made the point to say that the rules havent been read or understood. The implication is that I (and other f3'ers), are ignorant or to simple to comprehend the rules, where in fact, I was just qouting the wrong regulation. You should know that its not what you say that is important but the way you say it.

:banana:

[GSVR]

My bad, was thinking of pro-twins fuel regs.

To be fair though, you didnt say that you couldnt run avgas, you made the point to say that the rules havent been read or understood. The implication is that I (and other f3'ers), are ignorant or to simple to comprehend the rules, where in fact, I was just qouting the wrong regulation. You should know that its not what you say that is important but the way you say it.

:banana:

Well Kyle I thought you knew me better than that. And I have been on a bit of a crusade about making the F3 rules clearer since I started racing and couldn't understand them only to find every F3 racer I asked had a different idea about what they meant.

See you at the track again soon as theres something I want to ask you about the ProTwin bike you used to own.

[t3mp0r4ry nzr]

Well Kyle I thought you knew me better than that. And I have been on a bit of a crusade about making the F3 rules clearer since I started racing and couldn't understand them only to find every F3 racer I asked had a different idea about what they meant.

See you at the track again soon as theres something I want to ask you about the ProTwin bike you used to own.

sweet as Gary. If this has highlighted one thing, it is the odd nature of the F3rules and this is something I agree with you on. I do agree that there is an open interpretation on these rules and the problem is, what interpretation is correct. :sunny:

[wharfy]

sweet as Gary. If this has highlighted one thing, it is the odd nature of the F3rules and this is something I agree with you on. I do agree that there is an open interpretation on these rules and the problem is, what interpretation is correct. :sunny:

That's what lawyers are for !! :)

[neil_cb125t]

ive been running a 50/50 mix in mine since word go, the Av101 does burn slower so if you go higher than about 50% she cant handle the revs. I noticed a diff after i planned the barrels and advanced the ign ( but that what u have to do raise the octane to combat knockin ) now running high comp 444cc slugs again i need to.

its not bad for the donk - it is a better fuel thats why planes use it. it has more lubricating properties etc( speaking from Air force experience ) but all facts mentioned are true - it goes off quicker etc.

if your motor is standard then stay with pump - you'll get more gain out of not eating breakfast!!

but i get it free so i will use it - my 1.3 laser seems to llike it too.....

[CookMySock]

The local stock car fella (quite high up in stock car racing circles blah blah) says "Avgas is really hard on engines". He had some 200L drums of "Racing Fuel" that I didn't inspect closely.

Steve

[johan]

I might be worth mention that leaded AVGAS is bad for your modern engine with cat converters and O2 sensors.

The octane rating is not a horse power multiplier, stating the obvious.

I think in both WSBK and NZSBK leaded fuel (avgas) is not allowed. Max octane WSBK is 102 RON (90 MON). You probably need some pretty high compression to need this octane rating, but I don't know the details.

http://www.fim-live.com/en/sport/official-documents-ccr/codes-and-regulations/

Running AVGAS in a Ducati desmodromic design is probably a bad thing. The lead provides lubrication effect to valve seats, which can good for spring supported valves. In a desmo with minimal clearance between valve and rockers, it would probably wear pretty badly.
It was quite popular at Sound Of THunder to buy AVGAS, from what I saw.

Then there's the legal aspect, are you allowed to buy AVGAS as a private person? (tax reasons)

Not sure if I'm off topic already.

[Skunk]

Avgas is 100, can be as high as 140 but generally is 100-110 in NZ. Racing Fuel can be 100 to 140 too. You buy what you want.

[johan]

Avgas is 100, can be as high as 140 but generally is 100-110 in NZ. Racing Fuel can be 100 to 140 too. You buy what you want.

I think avgas is rated in MON, so 100 translates to how much in RON?

[Shaun P]

Avgas is 100, can be as high as 140 but generally is 100-110 in NZ. Racing Fuel can be 100 to 140 too. You buy what you want.

Avgas is now 100ll which is 100 octane low lead in NZ.

[Skunk]

I think avgas is rated in MON, so 100 translates to how much in RON?

Avgas is now 100ll which is 100 octane low lead in NZ.
I bow to superior knowledge...

[t3mp0r4ry nzr]

ive been running a 50/50 mix in mine since word go, the Av101 does burn slower so if you go higher than about 50% she cant handle the revs. I noticed a diff after i planned the barrels and advanced the ign ( but that what u have to do raise the octane to combat knockin ) now running high comp 444cc slugs again i need to.

its not bad for the donk - it is a better fuel thats why planes use it. it has more lubricating properties etc( speaking from Air force experience ) but all facts mentioned are true - it goes off quicker etc.

if your motor is standard then stay with pump - you'll get more gain out of not eating breakfast!!

but i get it free so i will use it - my 1.3 laser seems to llike it too.....

YOu gonna need more than 444cc slugs and avgas to stay in front of the gixxer4 this winter series Neil!

[sharky]

Cheers guys. I guess I'll stick with pump gas then for the time being.

[Mishy]

Avgas is now 100ll which is 100 octane low lead in NZ.

I asume that you are talking about the change from the old "rocket fuel" green stuff compared to the newer low lead replacement ?

[Mishy]

Cheers guys. I guess I'll stick with pump gas then for the time being.

I used to run Av in my mildly tuned F3 bike years ago. That was untill I found it made more power on the dyno with pump gas :2thumbsup
Things worth knowing - Pump gas has a higher caloric output - it produces more energy for a given amount of fuel burned, so don't use Av unless you have high enough cmpression to require it to prevent detonation. Also, the specific gravity of Av is slighly different to pump gas, and carbs with a certain jet size will lift differing abounts of each, so it could mean small jetting changes to a carburetted bike.
What others have said about the slow propogation of the flame front of Av is also true (from my knowledge) and is a reason why Av doesn't suit high revving engines with high piston speeds - it's designed for an engine running at a fairly fixed speed, and at altitude too.
If you want to do smething REALLY cool, try tipping a wee bit of methanol in :crazy: I litle re-jet and some meth used to do good things for mildly tuned 400's. I realise it's illegal, but ain't it fun doing something different ? (said the Actress to the bishop)

[Pussy]

I asume that you are talking about the change from the old "rocket fuel" green stuff compared to the newer low lead replacement ?
The last time I saw any 100ll (the purple stuff) was back in the '70s.
I haven't used Avgas at work for several years (only Jet A1), but the avgas thats still available is the green stuff. They may be calling it low lead, but it's just normal 100/130 leaded avgas

[roadracingoldfart]

Av gas is according to Mobil , where i get mine from , rated to min 110 octane , max 135 octane , im not sure if thats RON or not.
I spoke to a few people in the industry and they all
reccommend 48% 91 pump gas , 50 % avgas , 2 % tolluline.

I have run a ratio of 10 litres av gas to 6 litres 91 for several years and there has been no damage to the engine at all and i am keen to try the tolluline as i know what that can do to a good old bang in a can.

[Mishy]

Av gas is according to Mobil , where i get mine from , rated to min 110 octane , max 135 octane , im not sure if thats RON or not.
I spoke to a few people in the industry and they all
reccommend 48% 91 pump gas , 50 % avgas , 2 % tolluline.

I have run a ratio of 10 litres av gas to 6 litres 91 for several years and there has been no damage to the engine at all and i am keen to try the tolluline as i know what that can do to a good old bang in a can.


Those figures just sound plain wrong to me. Maybe 110 MON and 135 RON ?
Research Octane and Motor Octane ratings are always different for the same fuel.


As far as the blend goes, why do you need to do that ? Tolly isn't a magic horsepower gain, and the extra octane isn't important unless you have the compression to require it . . . . . . . . .

[Shaun P]

Just to clarify for those who care - straight off the net -100/130 avgas. The first number indicates the octane rating of the fuel tested to "aviation lean" standards, which is similar to the Motor Octane Number (MON) rating given to automotive gasoline. The second number indicates the octane rating of the fuel tested to the "aviation rich" standard, which tries to simulate a supercharged condition with a rich mixture, elevated temperatures, and a high manifold pressure.

[Mishy]

Just to clarify for those who care - straight off the net -100/130 avgas. The first number indicates the octane rating of the fuel tested to "aviation lean" standards, which is similar to the Motor Octane Number (MON) rating given to automotive gasoline. The second number indicates the octane rating of the fuel tested to the "aviation rich" standard, which tries to simulate a supercharged condition with a rich mixture, elevated temperatures, and a high manifold pressure.

Nice work :)
So we all know how Av compares to pump numbers now, eh . . . . . . . . . .