Petrol help...
Discussion
I stand ready to be corrected but...
As I understand it TVR's will run fine on ordinary unleaded (95ron), although they will run hotter and be more prone to pinking. I've been told in the past to run on S-unleaded (97ron+) and only use ordinary UL if I was caught short... and not to push hard. Having said that I've read posts on here by people saying they only ever use ordinary UL !?!
I guess it might just depend on the car ?? It also wouldn't hurt to use something like RedeX from time to time, irrespective of the fuel type as I think it contains cleaning agents...??!
G
As I understand it TVR's will run fine on ordinary unleaded (95ron), although they will run hotter and be more prone to pinking. I've been told in the past to run on S-unleaded (97ron+) and only use ordinary UL if I was caught short... and not to push hard. Having said that I've read posts on here by people saying they only ever use ordinary UL !?!
I guess it might just depend on the car ?? It also wouldn't hurt to use something like RedeX from time to time, irrespective of the fuel type as I think it contains cleaning agents...??!
G
Edited by GJR on Monday 2nd July 00:41
Such a lot of bo
ocks written about octane...
Octane doesn't give you any extra power on its own. If anything the addition of octane to fuel reduces any set volume or weight of fuel's overall calorific value (because you're diluting combustable fuel with octane).
All that octane does is to reduce the likelihood that it will self-ignite. The higher the octane rating, the more resistant it is to self-ignite.
What makes fuel ignite?
A. High pressures, leading to..
B. Heat
C. Sparks.
Why do you want higher octane?
1. So that you can increase your compression ratio to gain more power
2. So you can run your car more at the limit, where it generates more heat
3. So you can advance your ignition to gain more power.
Number 1 is only possible during engine design and assembly.
Number 2 is the result of racing.
Number 3 is only possible if number 1 isn't the limiting feature.
However, once numbers 1 and 3 have been set (at the engine build and mapping stages) they don't change. If your engine has been mapped for 98 then you ought to always use 98, or use 95 but don't thrash the car as hard as you would otherwise.
If your engine is mapped for 95 (and has no knock sensor) then IT CAN'T take advantage of advance timing for 98... i.e. you won't gain any benefit.
ocks written about octane...Octane doesn't give you any extra power on its own. If anything the addition of octane to fuel reduces any set volume or weight of fuel's overall calorific value (because you're diluting combustable fuel with octane).
All that octane does is to reduce the likelihood that it will self-ignite. The higher the octane rating, the more resistant it is to self-ignite.
What makes fuel ignite?
A. High pressures, leading to..
B. Heat
C. Sparks.
Why do you want higher octane?
1. So that you can increase your compression ratio to gain more power
2. So you can run your car more at the limit, where it generates more heat
3. So you can advance your ignition to gain more power.
Number 1 is only possible during engine design and assembly.
Number 2 is the result of racing.
Number 3 is only possible if number 1 isn't the limiting feature.
However, once numbers 1 and 3 have been set (at the engine build and mapping stages) they don't change. If your engine has been mapped for 98 then you ought to always use 98, or use 95 but don't thrash the car as hard as you would otherwise.
If your engine is mapped for 95 (and has no knock sensor) then IT CAN'T take advantage of advance timing for 98... i.e. you won't gain any benefit.
Well said mars. Octane is far less combustible than heptane (the other consituent in petrol) so it makes for a far more stable solution that is much less likely to self ignite. I always use 98 or 99 octane ful in the Cerbera as I find that it runs rough on 95, or even that 97 octane BP "Ultimate" (ultimately sh1te!). Pre-spark-detonation is a big problem in high compression engines such as those in TVRs if you use crap quality fuel.... BUT... if you never push the loud pedal more than 30% of the way to the floor then you would probably be okay on 95octane fuel - but where is the fun in that?
V8Cerbera said:
Well said mars. Octane is far less combustible than heptane (the other consituent in petrol) so it makes for a far more stable solution that is much less likely to self ignite. I always use 98 or 99 octane ful in the Cerbera as I find that it runs rough on 95, or even that 97 octane BP "Ultimate" (ultimately sh1te!). Pre-spark-detonation is a big problem in high compression engines such as those in TVRs if you use crap quality fuel.... BUT... if you never push the loud pedal more than 30% of the way to the floor then you would probably be okay on 95octane fuel - but where is the fun in that?
It's quite likely that your ignition map is quite retarded at low throttle openings, so detonation won't become a problem.Start to open up a Cerb running on 95 and you might find it pinks a lot, which ultimately will lead to your pistons being eaten I guess.
I haven't had any problems running my Cerb on BP Ultimate, but my current favourite is Tesco SUL. It seems to work quite nicely and is cheapy cheap.
Re: The Chimera... Confirming what dnb said above... I'm also not aware that any standard Rover V8 had a knock sensor, and I'm not sure how easy it would be to implement one aftermarket either. It'd be quite difficult to ensure that it didn't detect all sorts of EM and vibrations leading to a "knock" situation.
One practical application of a knock sensor is to determine if the fuel used has a lower RON than that which the engine is intended for. ION sensing seems to be the next big thing, which would allow the ECU to basically advance the ignition until just before the onset of knock all the time... which means you'll always have the best ignition map available to you no matter what fuel.
Although one of the contributors of another forum I'm a member of is dead keen on this technology, I'm not aware that any commercial afternarket products exist yet. It'll be bloody interesting when they do hit the street though.
ION sensors will become to ignition what wideband lambdas are to fuelling.
Edited by Mars on Monday 2nd July 16:31
Edited by Mars on Monday 2nd July 16:33
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