[roland2003]

Hi Guys,heres some info for you regarding how & why timing & fuel octane effect power;
First some octane facts for you ,nice & simple no heavy reading or showing off;-
OCTANE
1) The higher the octane the slower the fuel burns
2) The slower burn means its shoving down on the piston for a longer period as opposed to a short jab. So more time is spent per cycle 'working', and a more controlled burn is achieved aswell.
3) Octane in the UK is rated as Ron
4)The Mon number is around 10 less than the Ron number
5) In the US their octane is the average of the Ron & Mon ,so their 92octane is the same as our 97Ron.
6) The highest octane unleaded fuel you can get is around 106 Ron (cool blue)

IGNITION TIMING
1) A higher octane fuel will benefit from an advanced (ie earlier) spark.Within reason if you dont advance the timing for the better fuel you wont gain any power,but then you wont hurt anything either.
2) A lower octane fuel requires the timing to be retarded,(ie a later spark where the piston is furthur up the bore),if you do retard the timing you lose power but the engine runs fine. If you dont retard the timing the engine pinks (the US boys say ping) this loses power too but also runs serious risk of an engine blow up if driven under high load for any period (eg nailing it in 5th or 6th)
3) The anti-knock sensors in theory retard the timing automatically when it pinks. In reality the car still pinks and this is not going to save you .Never rely on the Anti Knock Sensor. They are better than nothing ,but only just!
4) Pinking can be heard as a light 'tinkling' or 'rattling' under load. ;-Stereo off,windows closed, ear towards windscreen,use at least 3rd gear up a hill and floor the throttle . Try at 3000,4000,5000,&6000rpm. One tiny little 'tinkle' (only) under these conditions is usually ok. If you can 'never' get the car to pink then it begs the question 'Could this car use a little more advance?' -which would give more power in the process.
5) Assuming the knock sensor is not cutting the timing back ,you will not gain power merely by adding a higher octane fuel.

POWER UPGRADES (re-map)
1) The earlier 163bhp MCS appears to have been mapped to run on very low octane fuel, they did this to ensure it didn't pink even on crap fuel.Hence as stock the 163 cars feel as flat as a pancake.
2) The later cars run more ignition advance , and would be more inclined to pink on the same crap fuel that the 163bhp cars can run ok on.This is where the 7bhp comes from. It makes the car more responsive low down too.
3) If we know the car will be run on a minimum of 97Ron, then one can advance the timing and reap the benefits. Earlier cars will gain more from just a remap than later cars. Effectivley they both end up with similar advance,but as the later car was half way their to start with it 'gains less'.
4) A remap only upgrade will not give anywhere near the power & torque of a pulley+remap conversion. Save your pennys and do it this way.
5) For power always use the highest octane fuel you can get (thats Tescos 99Ron at the moment) ,and map to achieve as much advance as possible but without it pinking.


Hope this helps ,Happy new year Roland GT Tuning

[62Lincoln]

Roland, thank you for taking the mysticism out of how the ecu uses timing to control knock. This write up should be required reading for anyone considering modding their car. The only comment I would suggest adding is regarding 'pinking': IMO, I would not rely upon the naked ear to always hear it. It's possible to have pinking that is not apparent to the ear (especially untrained ears, i.e. everyone other than a tuner's ears! ). IMO the safest route is to rely on your tuner, and know what parameters your car is running (a/f, etc.).

Thank you again for this excellent write up. How I dearly wish I lived on that side of the pond so that I could do more business with you! Happy New Year!

To the mods: This should be a sticky.

[roland2003]

Thanks guys.
Lincoln Yes untrained ears will easily miss/mistake ping for something else. Often a car (any make) will be pinking its nuts off and the customer still doesn't recognise it. Interestingly the (trained) naked ear is still regarded as the best way to detect pinking. A knock meter is effectivley a microphone with filtering measuring sound transients. The human brain can distinguish a 'ping' from an unrelated rattle or tap better than the meter.
All that expense and I still use my ears most of the time!
Regards Roland

[Brynster]

Quote: Originally Posted by roland2003

Thanks guys.
Lincoln Yes untrained ears will easily miss/mistake ping for something else. Often a car (any make) will be pinking its nuts off and the customer still doesn't recognise it. Interestingly the (trained) naked ear is still regarded as the best way to detect pinking. A knock meter is effectivley a microphone with filtering measuring sound transients. The human brain can distinguish a 'ping' from an unrelated rattle or tap better than the meter.
All that expense and I still use my ears most of the time!
Regards Roland

Are those the old Mark One ears or the improved, later, Mark Twos?

[roland2003]

Actually in the early days I found it hard to hear 'slight' pinking on the Mini. I kept grabbing the bunch of keys in the ignition as it sounded like they were rattling against each other. I sometimes take the Mini key off my keyring and use it on its own now ! So definatley improved Mark 2 ears I would say.
Regards Roland Gt Tuning

[Brynster]

That's good (as it's very hard to retrofit the better type)

[Brynster]

Quote: Originally Posted by Max

I'm now filling up with Tesco 99RON from now on (call it a New Year's Resolution )

I'm sticking with single malt.

[NeuroBeaker]

Great thread, thanks very much Roland.

[MINIdriver85]

Very interesting read.

[roland2003]

.Cheers guys ..Thats it brush off the cobwebs and it reads like new

[aries9]

So Roland
How about all those tin can upgrades (not the custom ones i mean) like lohen, minspeed that they are uploaded with bluefins, are they tuned for 95 98 or 100 octane or somewhere in the midle??

[roland2003]

Fair question, tbh you need to ask them as I dont know what they've gone for. It it were my Bluefin it would optimised for 99 Ron, and I would be testing on the road only (RR no good for this) listening hard and also watching data to see if it knocks back. Id want to achieve say 5 or 6 4th gear runs to the limiter in succession with possibly just a slight pink /timing knockback on the last run. Thats pretty much optimum balance. Too retarded and its flat, too advanced and it pinks tommorow but not today.

[alski]

can anyone here "you tube" a pinking soundtrack ?

[NeuroBeaker]

The most readily available premium fuel near me (that doesn't cost three limbs to purchase) is 97 RON... does anyone make maps to specifically suit that grading of fuel?

[MINIdriver85]

the best fuel i have near me is 98 Ron...then there is the Shell V-Power who is said to be 100 octane but i don't have it quite near so it would be better to not make a remap only for that fuel because I dunno if I can get it steadily, so i guess when i'm going to have my custom map made i should ask for a map for 98 ron fuel. What if with a map like that, i end using 95 Ron fuel once in a while?

[NeuroBeaker]

I dunno. Maybe get your remap loaded onto one of the portable Bluefin handhelds - that way you can put it back to stock if you're ever forced to fuel up with 95 (i.e. in the middle of nowhere and that's the only fuel on sale).

I'd like to get it optimized for 97/98 and then keep my bluefin handy for that reason. All my planned stuff is for spring when my current insurance runs out and I can switch to a mod-friendly insurer. I'm getting really excited about it - there's so many of Roland's products I've been literally dreaming about at night... for instance, last night I was dreaming he was installing his strut braces into my car - although strangely he didn't have a face - just a blank spot where a face should be. Never having seen a picture of him, my mind wasn't inventive enough to give him one in the dream.

...and you probably all think I'm nuts. Ah, well.

Quote: Originally Posted by alski (original)

can anyone here "you tube" a pinking soundtrack ?

And that's a good idea... do tell us at what time intervals the pinking comes in too!

[MINIdriver85]

Well, my engine mods are planned for spring too...lol. Sadly I'm in Italy so I can't have roland fit me his stuff...

[roland2003]

...well my sister lives in Italy. Maybe she can fit it.

[sam_a156]

Quote: Originally Posted by MINIdriver85 (original)

Well, my engine mods are planned for spring too...lol. Sadly I'm in Italy so I can't have roland fit me his stuff...

Hey, don't let that slow you down! I drove last summer Warsaw/Poland-GTT-Santa Margherita Ligure/Italy during my little road trip

[BigShow]

4) Pinking can be heard as a light 'tinkling' or 'rattling' under load

Ermmm... mine makes this noise... help