# Octane booster



## Hoggy (May 8, 2002)

Hi, Anyone regularly use Octane Booster, if so which one do you recommend ?
As my nearest V power is 20 miles away & the the VXR Nurburg is my every day car I have to put normal 95 in it, so would like to raise Octane to 98 at least.
I believe this is only the 2nd question I have asked in 12 years.  
Thanks, Hoggy.


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## jamman (May 6, 2002)

Joecool uses Millers Hoggy and swears by it wether it will raise by 3 is questionable


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## Callum-TT (Jun 3, 2013)

You thought about installing a methanol system?

Does cost a bit but with standard 95 Ron it raises it to approx 98/99.

I was put onto it by one of the guys from seat cupra . Net at GTI inters

I have looked into it myself and actually considering it. As I use 99 it would raise that to 103 but I would probably drop to 95 due to cost.

Let me know if you want any more info about it mate.

Sent from AutoGuide.com Free App


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## Danny1 (Sep 2, 2010)

Do you not have a Tesco closer? Their Momentum is 99 octane anyway, its all I use in the TT.


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## t'mill (Jul 31, 2012)

Same here. I started using it in my GT4, then Corrado 1.8 16v, Mk2 Golf GTI 8v, Mk3 GTI 16v, Rover Coupe Turbo and now the TT.


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## Hoggy (May 8, 2002)

Danny1 said:


> Do you not have a Tesco closer? Their Momentum is 99 octane anyway, its all I use in the TT.


Hi, No, Tesco don't stock Momentum, probably not enough call for it in this poor area of Wales.
Hoggy.


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## John-H (Jul 13, 2005)

Miller's Octane Plus you can use regularly which raises two RON points. More than that is possible but you risk damaging cats with some products.

Keep 'em coming :wink:


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## brian1978 (Jul 10, 2013)

Does using 99 over 95 make much difference?


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## Hoggy (May 8, 2002)

brian1978 said:


> Does using 99 over 95 make much difference?


Hi, Only if the engine is designed to run on the higher octane, otherwise Ign timing will be retarded to prevent knocking "pinking" especially on a turbo engine, resulting in less power.
Hoggy.


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## Skeee (Jun 9, 2009)

Hoggy said:


> Hi, Anyone regularly use Octane Booster, if so which one do you recommend ?
> As my nearest V power is 20 miles away & the the VXR Nurburg is my every day car I have to put normal 95 in it, so would like to raise Octane to 98 at least.
> I believe this is only *the 2nd question I have asked in 12 year*s.
> Thanks, Hoggy.


 

I don't know what engine the VXR has, but in the Mk1 Corsa GSI 16v (106 0r 109PS can't remember)  the difference between 95 and 99 was particularly noticeable.

Tbh I don't notice much difference in the TT but my petrol cap says 98 so (almost) always put 99 in.


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## brian1978 (Jul 10, 2013)

Hoggy said:


> brian1978 said:
> 
> 
> > Does using 99 over 95 make much difference?
> ...


The fuel cap on my TT says 98/95 Ron. I normally just use 95. 
Will using momentum which is 99 result in less power, what about using a 98 Ron super unleaded, will this be better worse or the same, if it's different what difference does it make?

I've used in the past a 98ron and to me I noticed no difference when I filled back up with 95. :?


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## Hoggy (May 8, 2002)

Hi Skee, The VXR Nurburgring really requires 100 octane, but 98 will do. 
95 will cause a loss of performance & I didn't buy it to get less performance than my VXR.
Hoggy.


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## Hoggy (May 8, 2002)

Hi Brian, It will take a tank of 98 Ron before ECU adjusts Ign timing fully to get the full performance back.
Reducing the Ign timing by using 95 happens quickly because of the knock sensors protecting the engine from "pinking".
The 225 is designed for 98 Ron & will be more efficient using 98 than 95.
My 225 has never used anything but Shell Optimax/V Power in the 12 years I have owned her.
Hoggy.


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## John-H (Jul 13, 2005)

Yes it's more with remaps but it might take a couple of tank fills to properly adjust - unless you do an ECU reset. The ECU is quick to retard and protect a soon a any knock is detected.

The higher RON V-power etc gives you a few percent extra mpg which can translate to power. I worked out once in my normally aspirated RS2000 4x4 from several weeks testing and logging that the higher octane (98 Optimax then) did enough extra mpg to pay for the extra cost.

With a remap it should be better. Don't go mad though - BP produced a 102 RON specialist fuel at twice the price but it produced less power on a remapped TT - reason we think is that the calorific value was lower and the higher octane rating couldn't be taken advantage of by the map which limited advance.


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## Hoggy (May 8, 2002)

Hi John, Yes as you say if Octane is much too high for the engine design, if can be the same as retarding the Ign & gives less power.
Hoggy.


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## brian1978 (Jul 10, 2013)

John-H said:


> Yes it's more with remaps but it might take a couple of tank fills to properly adjust - unless you do an ECU reset. The ECU is quick to retard and protect a soon a any knock is detected.
> 
> The higher RON V-power etc gives you a few percent extra mpg which can translate to power. I worked out once in my normally aspirated RS2000 4x4 from several weeks testing and logging that the higher octane (98 Optimax then) did enough extra mpg to pay for the extra cost.
> 
> With a remap it should be better. Don't go mad though - BP produced a 102 RON specialist fuel at twice the price but it produced less power on a remapped TT - reason we think is that the calorific value was lower and the higher octane rating couldn't be taken advantage of by the map which limited advance.


Ok so I'm better with 98 or 99 Ron, I'll use that exclusively, how to I do an Ecu reset?


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## John-H (Jul 13, 2005)

Yes I remember freegeek finding that out with his liquid. We tried looking up the ingredients and although we couldn't find the exact formula it was known that with different makeup of toluene, acetone and other stuff I can't remember you could achieve a higher RON without adding the Miller's component but acetone for example had a lower energy content. Not saying that they used that but it seemed obvious that achieving a higher RON could be done but possibly at a little less energy content - the only logical reason he achieved lower peak power. That was all measured with a full tank from empty, run for a while to clean out the lines from previous fuel and then an ECU reset and power runs in similar conditions e.g. road, temperature etc - he consistently got lower power with the BP 102 than Shell V-Power but using the same techniques the 99 V-Power produced significant gains over 95 RON standard unleaded.

For an ECU reset pull fuse 10 for a couple of minutes :wink:


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## brian1978 (Jul 10, 2013)

John-H said:


> Yes I remember freegeek finding that out with his liquid. We tried looking up the ingredients and although we couldn't find the exact formula it was known that with different makeup of toluene, acetone and other stuff I can't remember you could achieve a higher RON without adding the Miller's component but acetone for example had a lower energy content. Not saying that they used that but it seemed obvious that achieving a higher RON could be done but possibly at a little less energy content - the only logical reason he achieved lower peak power. That was all measured with a full tank from empty, run for a while to clean out the lines from previous fuel and then an ECU reset and power runs in similar conditions e.g. road, temperature etc - he consistently got lower power with the BP 102 than Shell V-Power but using the same techniques the 99 V-Power produced significant gains over 95 RON standard unleaded.
> 
> For an ECU reset pull fuse 10 for a couple of minutes :wink:


Thanks John


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## roddy (Dec 25, 2008)

hahha,, TT owners every where running down to car to pull fuse No 10 !! :lol:


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## Skeee (Jun 9, 2009)

John-H said:


> ........................ BP produced a 102 RON specialist fuel at twice the price ..............


 If you ever venture as far as Kent, Brands has Shell 105 at the pumps. Probably the same scale of pricing! :roll:

I've also seen cans of 115 and 125 at Goodwood but doubt that is for general sale. Besides, if it was then would probably need to arrange a mortgage if filling the tank!


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## brian1978 (Jul 10, 2013)

roddy said:


> hahha,, TT owners every where running down to car to pull fuse No 10 !! :lol:


If you drive the car in slow traffic would the Ecu think you are driving like a nun and adjust accordingly, making the car less aggressive, and would pulling the fuse to reset it back to the original more aggressive setting.

Also how long does it take the ecu to relearn you are not driving Mrs daisy after you return to your normal driving style?
I'm asking because from time to time I have to drive through Glasgow in rush hour traffic. Which means an hour or so of driving very slowly indeed.


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## Skeee (Jun 9, 2009)

brian1978 said:


> roddy said:
> 
> 
> > hahha,, TT owners every where running down to car to pull fuse No 10 !! :lol:
> ...


Isn't that a TBA you're referring to?


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## John-H (Jul 13, 2005)

The main thing we are talking about is ignition advance and the ECU triggered off the knock sensors to retard the ignition pretty instantly to protect the engine. It advances cautiously. How fast is based on a rolling average calculation and I'm not sure of the time frame. The anecdotal - takes a couple of tank fills to adapt is probably down in part to having half a tank of 95 when you fill with 99 and getting 97. So, best to empty the tank, full up with 99, drive for a bit to flush the pipes and filter, then pull fuse 10. Driving round town shouldn't specifically affect advance - it's things that might produce pinking like too high a gear up hill etc. There are adaptations like fuel trim too but I'm not convinced that would come into it either.


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## muz1990 (May 12, 2013)

i only use v power in my TT, only used it in my VXR and my 135i too!

the car manually adjusts to the fuel change itself though after a few hundred miles so im told by tuners!

the station in queensferry near me used to stock 102 octane fuel, people used to full up on it before going to Crail a while back lol wonder what 99 octane + octane booster would achieve :lol:


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## Templar (Mar 9, 2012)

I remember the previous BMW's having a learning type system for the auto box and ignition. If you drove in a certified way majority of the time it would adjust itself to your way of driving. Clever stuff but you didn't really know this had happened until you did a reset. To perform a reset it was something on the lines of, ignition on, off, on off, accelerator fully depressed. .ect ect. Once reset back to default the difference was very noticeable. 
Any idea if this is the case with the VAG software ?


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## Skeee (Jun 9, 2009)

Templar said:


> I remember the previous BMW's having a learning type system for the auto box and ignition. If you drove in a certified way majority of the time it would adjust itself to your way of driving. Clever stuff but you didn't really know this had happened until you did a reset. To perform a reset it was something on the lines of, ignition on, off, on off, accelerator fully depressed. .ect ect. Once reset back to default the difference was very noticeable.
> Any idea if this is the case with the VAG software ?


  "I refer the poster to the answer I gave a moment ago"


Skeee said:


> brian1978 said:
> 
> 
> > If you drive the car in slow traffic would the ECU think you are driving like a nun and adjust accordingly, making the car less aggressive, and would pulling the fuse to reset it back to the original more aggressive setting.
> ...


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## Templar (Mar 9, 2012)

So the VAG software does have learning capability. Is this across all VAG ECU's new and old ?


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## Skeee (Jun 9, 2009)

Templar said:


> So the VAG software does have learning capability. Is this across all VAG ECU's new and old ?


 Don't know the answer to that. But it was a new "feature" of the drive by wire throttle.


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## Templar (Mar 9, 2012)

I personally didn't like the feature on the Beemer, too invasive I thought. Would only take a couple of days pootling to work and back for it to assume that's how I always want to drive. Weekend cometh, time to play it was just nit eager enough until the reset. Very noticeable.


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## John-H (Jul 13, 2005)

It's not so much your driving style that's adapted with the TT's ECU, it's adaptation for fuel RON by listening out for pinking through the knock sensors. It also adapts fuel trim to optimise fueling mixture but none of this is a bias towards presumed gentle or aggressive driving. In fact it's probably more aggressive driving that would pick up any shortfall in the fuel anti knock additive and would be more likely to retard the ignition to protect the engine and give you lower performance. Re-adapting back to a good fuel takes a lot longer that adapting to a bad one - hence why a reset can restore performance but only when the fuel has improved.

There is an adaptation for throttle butterfly extent positions but it does this to learn the extents from a power disconnect (memory wipe) on first ignition switch on, with the engine not running. This is because it's a stepper motor and needs to count pulses and calibrate.

I've seen it stated that driving around slowly caused the throttle to be limited to 80%. I've not seen this proven anywhere, I can't see a valid reason for this and I suspect it's come from misunderstanding a combination of throttle reset instructions and ignition advance adaptation re-learning actually happening, following an episode of poor fuel.

There were other myths floating around in the early days like 225 TTs having bigger little ends than 180 TTs - they don't - but you know how these things get spread around :wink:


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## Templar (Mar 9, 2012)

What you say John makes a lot of sense. What I and many other members of the forum who had E46 model BMW's was a common experience and was discussed in several threads. Will see if I can dig out that far back and post up a link on here. Can't remember if fuel quality was mentioned as a culprit so to speak, but yes it does seem possible.


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## John-H (Jul 13, 2005)

It may be different for BMWs :wink:


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## Templar (Mar 9, 2012)

You would think that the principles would be the same, but who knows for sure. Either way it makes an interesting topic.


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## John-H (Jul 13, 2005)

What I was thinking is that things like fuel trim, maximum ignition advance and throttle reset etc are all things that have an optimum which should be the same for all types of driving but perhaps (and here I don't know) BMW had a feature specifically meant to learn your style. I'm thinking things like the dynamic linking between throttle and pedal.

There was a device called a Sprint Booster a while ago that went between the pedal connector and the loom, which modified the signal output from the pedal and passed the modified signal onto the ECU. Instead of simply passing on a 20% to 30% position change as a 10% increase, it would momentarily pass on perhaps a 30% increase and then quickly back it down to the correct 10% increase. The effect was like flooring the accelerator and then backing off but it did this quickly and smoothly. The impression given was that you had a bigger engine with more instant torque. Of course you didn't, you just had the same as before. Full throttle was no different it was just part throttle that was exaggerated.

I saw a patent for this technique for application within the ECU. It was basically proportional integral differential (PID) control with programmable coefficients for each of the three mathematical functions. The suggestion was that it could give different driving styles and the "feeling" of more power and torque for part throttle. It's not inconceivable that such a thing could have learnt PID coefficients.

Just my speculation but I wonder if such a thing could also be a factor. Did any of the marketing blurb say anything about learnt driving styles?


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## Spandex (Feb 20, 2009)

I've had a number of BMWs, including an E46 and have never believed any of the theories about gearbox resets, and despite trying them have never seen any improvement from doing it. I think its just a placebo effect - if you believe the theory, you'll feel a difference, if you don't, you won't.

It doesn't make any sense for a gearbox to learn over a large time window, because it doesn't achieve anything - a learning function that takes hours or days is never going to be in the right 'mode' for your current driving style. And why would they make a gearbox that happily learns when you drive gently, but seems incapable of learning from aggressive driving (instead, needing a reset)?

I've also read the technical docs for a few gearboxes and have only ever seen mention of short learning time windows (a few seconds at most). This makes much more sense - drive gently and the box changes up earlier and smoother, then as soon as you start accelerating hard, it holds the gears longer and changes quicker.. Then returns to the 'gentle, mode as soon as you back off.


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## John-H (Jul 13, 2005)

The gearbox is another dimension to this. A more sporty mode could be use of higher rev gear change points, keeping the revs higher when changing down for example, so you were in a low gear for acceleration if you suddenly put your foot down again. To "learn" thisi would only make sense over a few seconds. It's the sort of thing there's often a "sports mode" switch for.


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