Toluene as race fuel additive

[wez84]

Just wondering if anyone here has played round with mixing toluene with pump fuel or avgas for racing.
I currently run straight avgas in my speedway car but the avgas nowadays isn't as good as it used to be since they change it.
Would be keen to here from anyone with experience with mix there own race fuels

Wez

 

[sweefu]

I'm not sure what the raw RON rating of avgas is. I know a few people who use a mix of 98RON pump fuel and a 10% mix of toluene to boost the RON to 103 - 105 with good results. What sort of engine/fuel pump/fuel lines are you using?

 

[Decicrate]

I have run Toluene on quite a few occasions. It seems to work quite well at keeping detonation at bay. I usually only run it in the hotter months of the year.

Toluene has a rating of 114 from memory. I have a mate that was getting it for me and it was around $80.00 for a 20ltr drum.

It works out pretty expensive if you are trying to raise the octane level of your fuel by several points.

The calculation for working out the mix. Lets say your tank is 60ltr and you are currently running a 98 octane fuel.
then if we went 40ltr of 98 x octane rating + (20ltr of 114 x 1140) / 60 total ltr = 103.3 octane

hope this helps.

 

[wez84]

Cheers guys
Avgas used to be about 130 octane but now it's change to a funny rating something like 100 octane at lean mix and 110+ at rich mix.
My engine is a Holden v8 stroker
With a compression ratio of 10.5:1 and holley 750dp Holley blue pump and 1/2" standard fuel line.
The engine runs at 6000rmp around the track.
Iv read that a few people mix it at bout 30% with avgas but just seeing what some guys here have tried
might get some and try a mix and throw it on a dyno see what difference it makes.

 

[AirStrike]

What's the point tho really if your only going to bump the RON up a few points? Mine run's 18psi and 98 octane without a drama in the world.

 

[yxyx64]

Cheers guys
Avgas used to be about 130 octane but now it's change to a funny rating something like 100 octane at lean mix and 110+ at rich mix.
My engine is a Holden v8 stroker
With a compression ratio of 10.5:1 and holley 750dp Holley blue pump and 1/2" standard fuel line.
The engine runs at 6000rmp around the track.
Iv read that a few people mix it at bout 30% with avgas but just seeing what some guys here have tried
might get some and try a mix and throw it on a dyno see what difference it makes.

couple of thoughts but not knowing your class constraints.....10.5 is not huge for pump gas and adding more T actually gives you LESS energy per litre of fuel ( a bit like adding ethanol loses energy per litre ). Pump fuel already has some anyhow and I doubt you need any more.... also I doubt you get any benefit from avgas either but I am not looking at your motor to know. But I cannot imagine how much timing you have to need 105+ octane at only 10.5:1 even with iron heads.

BTW methanol is also a lower energy fuel but it just happens to have a high octane rating so comp can be upped...as well as it does a good job of cooling the engine before combustion.

If you really want a good bang fuel look into trinitrotoluene (LOL)

 

[FusionX]

Never mixed fuels, but have tested a couple of different fuels with one of our race cars on a dyno. We started with BP Ultimate to get a base figure, drained the tank and switched to Avgas. Managed to add a bit more timing and saw a nice increase in performance. From there we went to Sucregen E85. Managed to add a lot more timing compared to the avgas and about a 10% increase in power compared to the avgas.

I know quite a few race cars here use either the Sucregen or Powerplus E85. Bought a drum of it at the start of the year, 200L for $500, although someone told me the other day it cost them $550 so may have gone up, but also depends on the supplier. As we get a pallet sent with 4 drums on, saves on shipping.

Speaking to a couple of guys at the last tuning day with street cars, they were running a mix they call E42.5. A 50/50 mix of E85 and 98RON fuel and said it worked quite well. Note: We don't have E85 at fuel stations here in the West. Only E85 we get is race fuel.

 

[wez84]

Cheers for all ya input guys
I'm going to put in on the dyno and have a play just to see for myself what happens with different fuels and timing also was going to play with some carby spacers while it's on there. Just trying to get the engine to perform they way I need it to.