Jump to content
SAU Community

Recommended Posts

Obviously their not the same but are the same octane rating. He doesn't run avgas in it at the moment so there is no need to run it and their not really completely separate animals.

They might be the same octane rating but they don't share the same octane numbers. Apart from different burn rates, and the fact that Avgas contains TEL, the differences are vast. I again refer to MoTeC's testing on an engine dyno which suggests that V-Power Racing performed better than Avgas in every situation. The fact that the engine used was a 4G63 from an EVO IX only strengthens the argument that what they found applies to Skyline motors.

They ARE completely different products.

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3189555
Share on other sites

2rismo after all this you are confirming what I said in the first place. I'm in this for a discussion/learn.

The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early (pre-ignition or detonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise. The discovery that lead additives modified this behavior led to the widespread adoption of the practice in the 1920s and therefore more powerful higher compression engines. The most popular additive was tetra-ethyl lead.

Lead is also a good lubricant for valves which prolongs engine life and the avgas around now is 100ll which is low lead with anti knock additives added.

Avgas also burns slower due to if having to stay as a liquid at high altitudes.

I couldn't find their BTU ratings though.

This might have a little to do with it.

It might seem odd that fuels with higher octane ratings explode less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation as opposed to the ability of the fuel to burn (combustion). However, premium grades of petrol often contain more energy per litre due to the composition of the fuel as well as increased octane.

What is the go with the octane rating vs octane number I don't know.

Marine diesel or Jet A-1 could be better :(

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3189670
Share on other sites

thats what i thought too that one tankful wouldnt hurt..

anymore info on toulene mix.. where to buy, how much to mix, how much cost and how much does it boost the octane??

might do some search on toulene..

There's a thread in the performance section I think called "backyard race fuel" I got the link somewhere if you can't find it, but losta interesting stuff in it.

AVgas will also melt your CAT causing it to block up. Yes...in one tank. Much like leaded(super) petrol would do if you ran it.

lol...cat... :(

Marine diesel or Jet A-1 could be better :)

lol, have fun running diesel in a petrol engine and A1 is Kero so have fun running that too :) A1 does smell good though..... :P

I think half the joy of running avgas is the smell :( I'd never put it in my skyline but a friend usees it in his SS all the time :P

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3189759
Share on other sites

I found this in Wikipedia as well.

It is possible for a fuel to have a RON greater than 100, because isooctane is not the most knock-resistant substance available. Racing fuels, straight ethanol, AvGas and liquified petroleum gas (LPG) typically have octane ratings of 110 or significantly higher - ethanol's RON is 129 (MON 102, AKI 116). Typical "octane booster" additives include tetra-ethyl lead and toluene. Tetra-ethyl lead is easily decomposed to its component radicals, which react with the radicals from the fuel and oxygen that would start the combustion, thereby delaying ignition. This is why leaded gasoline has a higher octane rating than unleaded.

Don't hang me on the BTU rating but:

You stated that Avgas made less power why is this? I need facts.

As for Toluene I found it has a octane rating of 114. I have 20 litres at work and I know Snowy was put it in his car a while ago. Its commonly used as a knock deterent as far as I know.

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3189815
Share on other sites

my only reason for wanting to run higher octane was to reduce any chance of pinging...

i rarely have spirited runs let alone many runs in a row all day like in a drag day situation. so although i trust Benno's tune it still is unknown how the engine might behave on the track simply because its never been on one..

power increase was never my intention although i must admit R31Nismoids reply did make me think about fattening the power curve with better fuel..

but after reading the discussion and some good points made i decided to run on v-racing and see how it goes.. definately learned few things from this thread.. thanks for the replies...

thanks also for the links which i will be checking out...

edit: http://www.motec.com.au/fueltest/index.htm

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3190142
Share on other sites

There's a thread in the performance section I think called "backyard race fuel" I got the link somewhere if you can't find it, but losta interesting stuff in it.

yeah i found it last night and read thru most of it, was good reading..

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3190259
Share on other sites

Octane isn't the only measure of a fuel when you're after some protection for a track day. Some of the very high octane unleaded fuels will burn very rapidly compared to pump fuel and could result in a lean AFR. Motec's website has some very interesting fuel test data comparing avgas and v-power racing from shell.

had a look at the motec site, very interesting indeed..

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3190264
Share on other sites

Jetdat

If benno has set your tune with V power racing then don't touch it and race it with that fuel in the tank.

It will be fine.

I ran my car around sandown with his tune on vpower racing and the knock levels were fine all day.

Your engine has been tuned with the fuel characteristics of v power racing, don't go putting a higher octane rating fuel (even if it is unleaded) as this fuel will exhibit different burn characteristics etc

point taken archie01.

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3190265
Share on other sites

Jetdat.

If Benno tuned your car in V-Power Racing, DON'T use anything other than V-Power Racing.

You wont need to change anything. It's not like you are blazing away for 10-15 minutes on full boost, you are only blazing for maybe 10-15 seconds :O

If you are really worried, I can add some fuel to your tune temporarily on the weekend. It's not a permanent setting, it's a very basic add of fuel.

But, yeah, if Benno tuned it, it will be fine.

Link to comment
https://www.sau.com.au/forums/topic/173443-avgas/page/2/#findComment-3191570
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Latest Posts

    • So, I started this repair and got as far as "fixing" the holes with some fibreglass. God all those years working on boats came back quickly. I decided I'd reach out to some rust guys just to see what they would say about it. I came across a guy about 40 mins away and went to see him. He said the windscreen needs to come out, that there might be some more bits around the windscreen and he'd quote them at the time. But his quote was $300 to remove and replace windscreen and $3k for the damage he can see. He said he could respray the roof for $1200 and the bonnet for another $800 (somebody has previously rattle canned it, its horrendous). This is $5300 + any small additional bits. It's a lot, I get that and the name of one of my fave youtube channels 'Not Economically Viable' comes to mind.  I'm not being financially rational, but I've taken him up on the quote. He's opening a new shop in November with more room, so we're waiting for that. I'll leave the currently missing headliner out until then. I'm looking forward to it being fixed and having the paint looking nice again (lots of clear coat issues on the roof too). / flame suit on.
    • Oh and some up-and-comings; New rear drivers wheel bearing. I'll do that this weekend while the diff is out. The car is already up and the d/c axles and missing exhaust will help with space. This is the last bearing for me to do and I've been dragging my feet on it. I also have some new EBC blue stuff pads for the car and some new brake fluid. I haven't ever flushed the fluid in this car and looking forward to it. I have 600 degree fluid to put in. Not exactly "race fluid" but better than the typical stuff I have been using.
    • A proper clutch/plate type mechanical diff with quite a lot of pre-load and high locking % is better for drifting. Much more consistent in its behaviour. A helical can be annoyingly vague and inconsistent in how it responds under the sorts of abuse found in drifting.
    • Some updates here. I pulled the entire interior out, minus some trim to respray the seats with Colourlock dye. It turned out really nice though I accidentally let the dog in the car after and she scratched up the front seat.  This is what it looked like before, the colour was just washing out everywhere but thankfully the leather was in good nic. Then after the respray   And after the bloody dog jumped in The headliner is out waiting to be retrimmed, but it will stay out now until Nov - see why below. I replaced the stereo/headunit with a period-styled Android headunit. I have no after pics, but I'll get some. This is because of the missing pixels. I tried to fix this twice with replacement ribbon cables but couldn't. Also the bluetooth interface I'd bought for this was crap. Then there's the rusty roof. Pics and info in this other thread. I have decided to get this repaired professionally, but I'll update that thread. This is why the headliner will stay out for now. I'll be getting the roof and bonnet resprayed at the same time the rust is fixed. I also had an interesting issue with my drivers door lock.  For a small period I was having issues getting any 12v power to the car - I mean *any*. It would have no dash lights, nothing. It happened while I was at the shops and I couldn't get in the car. So, we had 2 problems. The most pressing here is that I was locked out. I have only a single physical key hole on the car, the drivers door and no amount of turning would unlock the car. Surely it doesn't need power for this? The second issue is why am I losing all power periodically, The battery isn't dead, its almost like the battery isn't even there. Two issues that were surprisingly easy to fix. You fellow BMW over-engineering lovers will appreciate this. The lock in the door has 5 states; mechanical lock, electric lock, neutral, electric unlock, mechanical unlock achieved at -90 degrees, -45 degrees, 0 degrees, 45 degrees and 90 degrees. Although, the unlock is towards the front of the car, so opposite for LHD countries. Sticking the key in and turning 45 left or right is what is used 99% of the time. It activates the central locking etc. 90 degrees is for dead battery access and, obvs, only un/locks the one door. But because the mechanical lock is never used and is 27 years old, it seizes up. I was totally unable to turn the key far enough to get to the mechanical unlock (At the time of locking myself out, I didn't even know this was a thing). I eventually did it with some vicegrips and teflon spray.  I made a quick vid for other E39 peeps.   The battery issue is totally new to me also - It wasn't making sufficient contact between the post and the terminal. The terminal was bolted on tight, but the car wouldn't have power. After checking the battery with my multimeter I accidentally contacted the terminal and the battery post and the car got power. The battery was only a few years old and in good condition. I cleaned the post and the terminal with a wire brush, bolted it back on tight and never had the issue again. I'm still surprised that despite having solid contact it didn't work. Also, the car was getting Warragamba sized pools of water in the back when it rained. My initial concern was another rust problem. But when I went out on Weds while it was raining and while I had no headliner in I could see a steady stream of water coming through the roof mounted aerial. As this aerial is for the (now removed) car phone I pulled it out and whacked a blanking grommet in the hole. It seems fine now. I'm thinking I might get the hole permanently filled when the rust is fixed. Moving forward and things in progress; The tailgate needs some attention. I have taken all the trim off to clean it all and address some small rust spots. I have partially done all of this but I'll finish it up hopefully this weekend. As all the trim are now entirely devoid of trim clips I have bought a heap of strong velcro and I'm hoping it does a good enough job as any of this trim in good condition is super expensive and usually in Europe as we dont have many of the wagons here. Suspension and brakes!!! This is exciting. In the front; New control arms New sway bar links New lower Eibach springs (the only modification I'm planning on this car) M Sport shocks (these came with the car and will replace the longer shocks in the car) New top mounts Used 540i calipers (stock brakes suck!) New 540i disks and pads (22x296 mm for 528 and 30x334 mm for 540i) New front wheel bearings (thank all that is holy for bolt on bearings!) Annnnd in the back; New control arms New sway bar links Adjustable air suspension arms (fool the car into what the current height is so the self levelling suspension can match the new front ride height) New ball joints I'll also be doing a brake fluid flush while I'm in there. I'm planning on switching the car over to the 16's that came with it so I can clean up and respray the M Sport 17's. They've lost a lot of colour over the years and have some gutter rash. None of this will start until the E90 is back.
    • You mean you will regret it for drifting duties? I don't quite follow.
×
×
  • Create New...