Octane Boosters will they give you more power

[steve99]

Octane Boosters will they give you more power ?



Well maybe yes maybe no, depends on a number of factors.

Octane is a measure of fuels resistance to detonation (knock) not a measure of the energy value or content of the fuel.

Example Ethanol (like in E85 fuels aprox 105 octane) has a higher octane rating than most pump petrol (eg 98 ron) but its energy value is about 30% less than petrol.

you can get more power out of your BRZ/86 running E85 fuels as you can run more ignition timing but you will use about 30% more fuel . Hence to need to retune for E85 fuels as fueling need substantial adjustments as well as timing

Cheap octane booster for these cars if your petrol does not already have 10% ethanol added , is to add 10-15% ethanol, you can do this by adding arround 6 litres of E85 fuel to a full tank of your normal petrol. You can do this on stock tune just dont go beyond 20% E85 as it will throw fueling to far off.

Stock Cars

A stock brz/86 on stock tune is designed to run on 98ron fuel in order to produce the rated power. Although some 98ron fuels still are not good enough like our 98 ron in Australia.

The simplest way to tell if the engine is running maxium ignition timing is to look at an ECU parameter called IAM (Ignition Advance Multiplier). You need some form of logging device (Its not available via standard obd readers like android torque app and a ELM327 adapter unfortunatly).

you need Techstream or a tuning system like Ecutek, Tactrix or Openflash tablet etc to read parameters directly from ECU.

The IAM is one of the methods the ECU uses to adjust timing when knock is detected. It part of coarse ignition timing correction.

On a stock tune the IAM start out at 0.7 so the engine is not running full timing, likely a safety measure as same tune is used worldwide for varing fuels.

If no significant knock is detected during engine operation then the ECU will start to increment the IAM towards 1. Once the IAM is a 1 then the engine is running maximum ignition timing and you should be producing close to the rated output by the manufacturer.

If you now fill up with say 95 ron fuel , then its very likely the ECU will detect knock and the IAM value will be lowered below one , maybe down to say 0.5 or some value where the ECU programming is happy with the levels of knock being detected.

On low quality fuels the ECU will always be detecting some knock and this knock will signal the ECU to keep the IAM below 1 to protect the engine, but it also reduces the output power and you may also get slightly worse economy as the ecu also richens up fueling when IAM is below 1 as a further measure to counter knock.

Once you fill up again with 98 RON or above knock will reduce and IAM will start climbing towards 1 . The ECU is always testing the limit to see if it can return the IAM towards 1.


So if your relatively knock free and the IAM is one ie your on good 98 ron or better then adding OCTANE booster will do nothing.

If your in South Africa on 95 RON and your IAM is around 0.5 then yes adding octane booster will give you a bit more power as it should reduce knock the ecu sees and allow the ecu to run with the IAM at 1.

Tuned Cars

Now the senario is different with "tuned" cars.

Almost every tuner on these cars will adjust the "tune" for max power and minimum knock on the local fuel available. This means the IAM is going to be 1.

So if you have taken your car to a tuner and he/she has tuned it for 95 ron, then its almost certain that it will now run on 95 RON fuel with minimal knock and hence your IAM will be one.

This now means if you add octane booster to your tuned car (assuming your running the fuel it was tuned for) then the ECU has no more to give timing wise.

In this case your pretty well wasting the octane booster , unless you just want a bit of added protection on a hot track day.

The tuned car will make more power safely on 95 ron than the untuned car as the tuner will have adjusted many parameters such as fueling, timing, intake/exhaust valve timing, temperature compensations, injection ratios ect to specifically suit 95 ron fuel you guys have available.

Just relying on the IAM to compensate is quite a "crude' method its used my the manufacturer to save then engine from damage rarther than make max power on lower quality fuels

hope that makes sense

Once the ECU has the IAM set to 1 then thats it ignition timing wise, even if you put 105 octane in the car its not going to make more power, but better fuels give you more safety margin when driving hard on hot days for example. If you want to take advantage of higher octane fuels beyond what the car is "tuned" for you will need to adjust the ECU parameters to suit to get the power advantage

[ShaunWRX]

Originally Posted by steve99

Oc

Stock Cars

A stock brz/86 on stock tune is designed to run on 98ron fuel in order to produce the rated power. Although some 98ron fuels still are not good enough like our 98 ron in Australia.

If your in South Africa on 95 RON and your IAM is around 0.5 then yes adding octane booster will give you a bit more power as it should reduce knock the ecu sees and allow the ecu to run with the IAM at 1.

All we needed to hear. Thank you Steve

[Dammod]

Thank you Steve...

[sav]

Thanks Steve, now Dammien and Shaun can finally understand.

[ShaunWRX]

Originally Posted by sav

Thanks Steve, now Dammien and Shaun can finally understand.

tears I tell you, tears!

[Fish Eagle]

Not all octane boosters are created equal...
Some are more equal than others

[sav]

That is a true story. The one you're using there is very good when used in moderation but if not it has been known to cause knock...when you fall over.

[Freedom]

Originally Posted by Fish Eagle

Not all octane boosters are created equal...
Some are more equal than others

Does RGM have more stock?

[Dammod]

Originally Posted by sav

Thanks Steve, now Dammien and Shaun can finally understand.

You are a piece of work man...

And to think last year I was having to explain IAM to you:

Originally Posted by sav

I'll have a look. Might be a better idea to do some logging via Techstream.

[Dammod]

Originally Posted by Freedom

Does RGM have more stock?

Have your tried running around 10% E95 per tank of fuel? Burns better and is far cheaper then Torco, or most octane boosters for that matter.
The stock tune can accommodate it no problem.

[Fish Eagle]

I don't routinely use any octane booster, only when I go on track, then I pop in a tin of LM for knock protection.

I've never felt any difference in performance whatsoever.

[Dammod]

Originally Posted by Fish Eagle

I don't routinely use any octane booster, only when I go on track, then I pop in a tin of LM for knock protection.

I've never felt any difference in performance whatsoever.

Originally Posted by Fish Eagle

That's probably the cause of your poor performance at the drags.

My car runs 10-15% down on power without octane boosting. It obviously pulls timing. I don't use octane booster all the time, just when I do track days, and then the power difference is very noticable.

Lately, I've been getting satisfactory results on the highveld from Sasol 95 + Liqui Moly Octane Booster at approx 1 tin per 25 litres, and I start 2 tankfuls before the event to give the ECU time to adjust. At my home altitude (750m) I find Engen 95 the best and most consistent without octane boosting, but YMMV.

Latest Liqui Moly price is about R78/tin (bought today for Sunday's track session).

PS: Just watched the video. I don't know much about drag racing, but something's wrong with either your tyres, warming them up, or your technique because launching's not coming together...

http://www.ft86club.com/forums/showp...6&postcount=40


???

[Freedom]

Originally Posted by Dammod

Have your tried running around 10% E95 per tank of fuel? Burns better and is far cheaper then Torco, or most octane boosters for that matter.
The stock tune can accommodate it no problem.

No, I've tried just one tin of LM OB at a track day, but it's not something I run permanently, it's also easier/convenient to get a can of LM OB than ethanol. But it's worth exploring.

[Dammod]

Originally Posted by Freedom

No, I've tried just one tin of LM OB at a track day, but it's not something I run permanently, it's also easier/convenient to get a can of LM OB than ethanol. But it's worth exploring.

Agreed, LM is more convenient.
You buy E95 in 25+ L Containers and then you could decanter into a smaller 5L, get to the petrol station, pop the E95 in then fill up so it mixes nicely so not tooo bad.

I would run it permanently if not tuned for the reasons Steve mentioned but the stock ECU is pretty aggressive in detecting knock and retarding timing.