Octane booster - should I or shouldn't I?
Discussion
I'm off to Scotland tomorrow morning in my 98S Chim 450 for a whole week! I've been looking at the locations of the BP and Shell petrol stations and found that the places I want to go to i.e anywhere north of Fort William are going to be out of reach when using Shell Optimax (what I have always used) or BP Ultimate.
It seems that the Shell station in Nairn (east of Inverness) is the farthest north, but with a typical average run I get about 240 miles from a tank and that's without too much heavy right foot (which if i'm not very mistaken should be the order of the day!). I'm worried about running out of fuel big time!
I have a 5 litre tank of Optimax as reserve.
Should I get a bigger plastic tank? But most importantly....
Can I use Octane booster with normal unleaded in my car? Do you have any experiences of using Octane booster? By using it will I have suffer any adverse effects over the space of a weeks driving? And can I get it from Halfrauds?
Any help much appreciated!
Richard
It seems that the Shell station in Nairn (east of Inverness) is the farthest north, but with a typical average run I get about 240 miles from a tank and that's without too much heavy right foot (which if i'm not very mistaken should be the order of the day!). I'm worried about running out of fuel big time!
I have a 5 litre tank of Optimax as reserve.
Should I get a bigger plastic tank? But most importantly....
Can I use Octane booster with normal unleaded in my car? Do you have any experiences of using Octane booster? By using it will I have suffer any adverse effects over the space of a weeks driving? And can I get it from Halfrauds?
Any help much appreciated!
Richard
Steve
Used Octane booster in my Griff a few years ago; perfectly acceptable means of restoring octane to 98 or more. Only difficulty is can't buy it from Halfords etc. Suggest if you have a hotel/B&B address where it can be posted to for you to pick up, motorsport suppliers like www.demon-tweeks.co.uk can post it for you to collect Had this problem in West Cornwall over the last few days. Totally unprepared, but should have expected it really. Couldn't find a Shell (preferred) of BP filling station anywhere in or around Penzance and The Lizard. Ended up using standard 95 Octane unleaded with no booster, as I couldn't find any of that either! 
Car ran ok and didn't 'pink' at all. I suppose there was a quarter tank of Optimax left when I filled up, so that would have diluted it a bit.
Car ran ok and didn't 'pink' at all. I suppose there was a quarter tank of Optimax left when I filled up, so that would have diluted it a bit.
I sell octane booster .. with optimax you get 101-102 RON on the top of the range.
If you use pump fuel to standard 7800:2000 you're guaranteed a minimum base RON, funnily enough some competition fuels don't guarantee a minimum RON at all
octane booster is great for if your car is prone to pinking in hot weather, or you're expecting to be putting it under heavy load outside of that which you would normally and want a safety buffer or have a car that is prone to pinking but has non-adjustable timing such as early cerbies.
If you use pump fuel to standard 7800:2000 you're guaranteed a minimum base RON, funnily enough some competition fuels don't guarantee a minimum RON at all
octane booster is great for if your car is prone to pinking in hot weather, or you're expecting to be putting it under heavy load outside of that which you would normally and want a safety buffer or have a car that is prone to pinking but has non-adjustable timing such as early cerbies.
Thanks for the comments guys!
101-102 RON!!! I like the sound of that! Didn't think of adding it to Optimax.
Setting off in an hour, so I'm going to play it by ear. I've never ran it on 95RON, but am prepared to do it with some Optimax in the tank at least (if I have to round the north coast). I may just have to go easy up there.
Preparation is the key and I should have got Octane booster ages ago. Ah well, nevermind... I'll have a brilliant time anyway (my first trip to Scotland and I'm travelling with my mates diesel 156!)
He won't have a chance, as long as my pit stops are quick!
Thanks again
Richard
101-102 RON!!! I like the sound of that! Didn't think of adding it to Optimax.
Setting off in an hour, so I'm going to play it by ear. I've never ran it on 95RON, but am prepared to do it with some Optimax in the tank at least (if I have to round the north coast). I may just have to go easy up there.
Preparation is the key and I should have got Octane booster ages ago. Ah well, nevermind... I'll have a brilliant time anyway (my first trip to Scotland and I'm travelling with my mates diesel 156!)
He won't have a chance, as long as my pit stops are quick!
Thanks again
Richard
Sorry to hijack this thread but can someone elaborate on what RON rating is and why (or not always why) a higher rating is better.
I know that normal is 95, super 97/8 etc but what is it referenced against? Octane is very familiar to me from chemistry days (and a few fuel/air bomb experiments
) but what else is actually in petrol if petrol is not octane? I assume there is a fair list there depending on which company. And what are the constituents of octane boosters?
FWIW my Griff 500 seems happy to run on either normal or super, though optimax does make a discernible difference. The BP equivalent does not however. I don't get pinking if I use 95 RON, though I once had a very bad run with some standard petrol bought at a well known supermarket.
Dave
I know that normal is 95, super 97/8 etc but what is it referenced against? Octane is very familiar to me from chemistry days (and a few fuel/air bomb experiments
) but what else is actually in petrol if petrol is not octane? I assume there is a fair list there depending on which company. And what are the constituents of octane boosters? FWIW my Griff 500 seems happy to run on either normal or super, though optimax does make a discernible difference. The BP equivalent does not however. I don't get pinking if I use 95 RON, though I once had a very bad run with some standard petrol bought at a well known supermarket.
Dave
RON is Research Octane Number. It is a measure of the propensity of an air-fuel mixture to self ignite. This leads to Knocking (heavy self-igniting) or Pinking (lighr self igniting). Diesel fuel does this by design.
A high compression ratio gives more chance of pre-ignition.
A high octane number prevents self-ignition.
Turbochargers give an effective higher compression ratio so more propensity to knock.
You want the bang in the cylinder to start with the spark and not before.
I don't know why retarding the ignition helps prevent knocking/pinking unless it lowers temperatures.
Russ
A high compression ratio gives more chance of pre-ignition.
A high octane number prevents self-ignition.
Turbochargers give an effective higher compression ratio so more propensity to knock.
You want the bang in the cylinder to start with the spark and not before.
I don't know why retarding the ignition helps prevent knocking/pinking unless it lowers temperatures.
Russ
retarding the ignition compensates for the faster flame front of unleaded fuels, and also compensates for the lower octane fuel,s propensity to self ignite at high pressures/temps ..
if you have a flame front travelling across a chamber, the pressure rise can cause the rest of the unburnt fuel to spontaneously combust, so losing you the controlled burn you need. By retarding the ignition you start the initial flame later , the the pressure increase is reduced since the piston starts further up the bore towards top dead centre.
if you have a flame front travelling across a chamber, the pressure rise can cause the rest of the unburnt fuel to spontaneously combust, so losing you the controlled burn you need. By retarding the ignition you start the initial flame later , the the pressure increase is reduced since the piston starts further up the bore towards top dead centre.
When i first got the Griff I brought it in to you Joolz and you corrected the pinking by adjusting the timing or mix, or something, after which it has been fine on Optimax... pinks like sod on anything else mind.
It had its service at main dealers a few weeks ago and this weekend on the BNG run up to Helmsley when we were giving the cars some serious stick on the acceleration front, it started pinking like hell at the high rev range.
This is most annoying. Is there a quick fix or adjustment that any small local garage could do? as I can't get it to main dealer and I know you're always stacked Joolz.
al
It had its service at main dealers a few weeks ago and this weekend on the BNG run up to Helmsley when we were giving the cars some serious stick on the acceleration front, it started pinking like hell at the high rev range.
This is most annoying. Is there a quick fix or adjustment that any small local garage could do? as I can't get it to main dealer and I know you're always stacked Joolz.
al
On the Scoob I have a microphone bolted to the block, connected to a load of electronics to light LEDs when it's knocking.
I've npot got this on the Griff yet, but I'm told that if it pinks then you can hear it.
I may employ a modified version of the electronics in the Scoob to monitor this.
I've npot got this on the Griff yet, but I'm told that if it pinks then you can hear it.
I may employ a modified version of the electronics in the Scoob to monitor this.
[quote=tail slide] Only difficulty is can't buy it from Halfords etc.
When I was using octane booster in addition to super-unleaded on the '99 450 (ie: with cat),( because of some intermittent high speed wide throttle pinking - which has virtually gone since I sorted out the loose vacuum advance capsule) I used the "STP POWER BOOSTER", which "increases octane rating" and - importantly "safe for cat' s".
AVAILABLE FROM HALFORDS...
250ml treats 50-60l (i.e: a full tank)and I think costs about £3.50.
PS: Muttsnuts, re: "what does pinking sound like?"
traditional description is along the lines of "the sound of shaking nails in a bucket", but the onomatopoeic (I did check the spelling) word "pinking" actually is a damn good fit.
Quite hard to miss it really. Typically heard at low revs and wide throttle / high load (i.e: in wrong gear ) or more unusually (except in TVR Power motors it seems) at high rpm and wide throttle.
>> Edited by tahiti450 on Tuesday 3rd August 20:25
Only difficulty is can't buy it from Halfords etc. When I was using octane booster in addition to super-unleaded on the '99 450 (ie: with cat),( because of some intermittent high speed wide throttle pinking - which has virtually gone since I sorted out the loose vacuum advance capsule) I used the "STP POWER BOOSTER", which "increases octane rating" and - importantly "safe for cat' s".
AVAILABLE FROM HALFORDS...
250ml treats 50-60l (i.e: a full tank)and I think costs about £3.50.
PS: Muttsnuts, re: "what does pinking sound like?"
traditional description is along the lines of "the sound of shaking nails in a bucket", but the onomatopoeic (I did check the spelling) word "pinking" actually is a damn good fit. Quite hard to miss it really. Typically heard at low revs and wide throttle / high load (i.e: in wrong gear ) or more unusually (except in TVR Power motors it seems) at high rpm and wide throttle.
>> Edited by tahiti450 on Tuesday 3rd August 20:25
Well I'm back and thought I should report my experiences..... I managed, like you tahiti450, to get the STP Power booster from Halfords. Only used 2 of the 4 bottles, as I wanted to see what the car would run like on ever decreasing RON. I started off with Optimax at home then generally put in half a tank of fuel at a time whilst on my travels. At first Ultimate and then standard unleaded with the octane booster and then just standard unleaded. So I suppose it never really got down to 95RON as as I came further south again I used BP Ultimate.
There were no issues arising from lower octane fuel i.e no pinking. But I did notice less performance when I had largely 95 in the tank. And occasionally not a knock, but a flap, flap, flap noise after decent periods of speed in the 3 figure range, coming back off the throttle to return to more sane speeds. Is this pre-ignition or somethingelse entirely??
FYI my oil pressure has always (since purchase March) been a consistent 42 ish at idle and normal driving, dropping to 30 under heavier acceleration and cornering loads. Not knowing much (if anything) about engines, does this indicate I have a high compression ratio?
Anyway, I did 1500 miles at an average of 24.5mpg
which I am very impressed with because I started to press on a lot after the first day up to Skye. But I suppose, with not much starting and stopping and constant radius open bends that you can monster at high speed (but not above the speed limit officer of course! 
) it's not that surprising. Standard Unleaded at 92.9p in Scourie was though!
Richard
ricardinho said:
There were no issues arising from lower octane fuel i.e no pinking. But I did notice less performance when I had largely 95 in the tank. And occasionally not a knock, but a flap, flap, flap noise after decent periods of speed in the 3 figure range, coming back off the throttle to return to more sane speeds. Is this pre-ignition or somethingelse entirely??
Maybe a bit of backfiring on the overrun? Maybe the exhaust is pulling in a bit of air somewhere when it gets well hot at high speeds. Certainly not preignition if your foot was off the throttle.
Seems a very good mpg for a 450 engine, wonder if it's a fraction weak on the mixture. Maybe other Chim owners could comment on their mpg figures...
ricardinho said:
I'll have a brilliant time anyway (my first trip to Scotland and I'm travelling with my mates diesel 156!)
He won't have a chance, as long as my pit stops are quick!
My diesel 156 would have been that green blur that overtook you just outside Fort William (when you were on full fat unleaded) :-) Oh, and it runs on any old cr*p and gives 42mpg!
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