25 replies to this topic

[carbon]

Toluene will increase the octane, but you need to blend in a lot of it to make a difference. Not something you can do on a garage forecourt.

Returning to the question about this 1380 - do you know the ccs in the combustion chambers?

By my crude maths if it is a standard chambered head the CR is well over 13:1 with flat-tops.

[Bradley Gaunt]

The pistons aren't completely flat top, I reckon they have about 3cc dish - see attachment.

 IMG_0132.jpg   37.67K   6 downloads

I dont know the cc of the head chambers but assume its about 25cc.

Edited by Bradley Gaunt, 11 November 2012 - 08:02 PM.

[ianclark1275]

millers CVL and Vpower is what i use in the race car 12:1 28 deg Adv

IC

[jaydee]

I've tried kerosene but it does not work and to be honest dont know how big companies like STP etc. sell it as an octane booster
But toluene does work, its the oil that you put in the solution that lowers the octane rating

[jaydee]

The pistons aren't completely flat top, I reckon they have about 3cc dish - see attachment.

 IMG_0132.jpg   37.67K   6 downloads

I dont know the cc of the head chambers but assume its about 25cc.

Could well be around 12:1

[dklawson]

The statement/question was made "how x additive could be considered an octane booster".

People often equate octane with "power". That is not directly the case. Higher octane fuel will allow you to alter the tuning and timing of an engine to get more power. However, by itself, higher octane fuel has no more power than low octane fuel. So what do the additives do? Their main task is to slow/smooth the burn of the fuel air mixture to prevent detonation. Can Kerosene do that? Maybe. Can Toluene do that? Again, maybe. Are any of these solutions cost effective? Not really. Most additives greatly increase the cost of your fuel when enough of the product is added to the tank. If you are not utilizing your engine's full power all the time, it is typically easier (and certainly less expensive) to de-tune the engine so you can use more readily available fuel without additives.

Though I do like water injection as I mentioned earlier, today's systems are very expensive compared to what I utilized years ago. You will have to drive a lot of miles to pay back the cost of water injection compared to additives. De-tuning is obviously the least expensive option.

[carbon]

Adding any kerosene (paraffin, diesel, etc) will kill the octane drastically, even at fairly low % addition.

Toluene, Xylene, Methanol, Ethanol, IPA, Acetone are all capable of boosting octane, but really need to be added in 10's of % to make appreciable difference.

Cheapest way of boosting octane in UK is to start with Shell V-Power or Tesco's 99. If you need anything more then add in Tetraboost or other similar.

[Cooperman]

First of all, have you changed the ignition advance curve to cater for the high C.R. The curve needs to have more available advance, but to advance more slowly up to max. advance.
Then you need to always run on 98 to 99 octane petrol, ideally Shell, with Castrol Valvemaster-Plus as an additive in slightly higher volume than is shown on the bottle.
In my 1310 cc 'S' with 11.2:1 C.R. I use about 10% more Castrol Valvemaster-Plus than recommended and Shell V-Power petrol and can rune the advance needed for full power without 'pinking'.

[Carlos W]

What about the Tesco high octane fuel? Is that not 99 ron compared to shell optimax 98?

[Mini118118]

Can I just say I'm not an expert in this field by and shape or form I'm currently driving a 998 Auto and I just wanted to add that I can see a definite gain in power when I use Esso 97 Super unleaded... I have used them all tesco 99, BP ultimate and Shells v power and I beg you to try it from an empty tank there is defiantly something going on power is up, I notice as the gear durations change quicker and the car is more responsive all 45hp of it... Someone ele try it and post a comment..

[Bradley Gaunt]

What about the Tesco high octane fuel? Is that not 99 ron compared to shell optimax 98?

I think Optimax was replaced with Vpower which is 99 ron.

Can I just say I'm not an expert in this field by and shape or form I'm currently driving a 998 Auto and I just wanted to add that I can see a definite gain in power when I use Esso 97 Super unleaded... I have used them all tesco 99, BP ultimate and Shells v power and I beg you to try it from an empty tank there is defiantly something going on power is up, I notice as the gear durations change quicker and the car is more responsive all 45hp of it... Someone ele try it and post a comment..

This is strange because as dklawson points out, the energy in the fuel is no different, its just the level at which combustion takes place which is altered by the octane level so your 998 has static timing and wouldnt alter in respect to octane change meaning no advance of timing and therefore no increase in power... thats the way I understand it and I'm no expert either .

First of all, have you changed the ignition advance curve to cater for the high C.R. The curve needs to have more available advance, but to advance more slowly up to max. advance.
Then you need to always run on 98 to 99 octane petrol, ideally Shell, with Castrol Valvemaster-Plus as an additive in slightly higher volume than is shown on the bottle.
In my 1310 cc 'S' with 11.2:1 C.R. I use about 10% more Castrol Valvemaster-Plus than recommended and Shell V-Power petrol and can rune the advance needed for full power without 'pinking'.

I took it to a rolling road where the guy set the megajolt map up so I cant be certain but I know he is very good and therefore assume he set it up correctly. In reflection to some of the posts I reckon I'll have my 2 available maps set for 99 Vpower and 99 Vpower with Millers CVL.