Octane booster - Worth it?

[bluess57]

Hey everyone,
Just wondering what people thought about octane booster and whether its worth it. I didn't run with any @WSID on Sunday and car survived fine (clutch didn't though)

Anyone one with logged data / real evidence?

[NickS]

I have absolutely no data to back me up but I always run Octane Booster on track days ... better to be safe than sorry !!!

Sunday was so bloody hot that Sonny pulled 2 degrees and I added two bottles of Octane Booster ... just to be really safe.

[bluess57]

Was thinking about the AFR "situation" on hot days,
my assumptions are:- the air is less dense (less O2 molecules per volume) therefore the tune is actually richer (only slightly of course). So I'd assume some protection there. Also the tune is pulling timing due to intake temps as well.
So adding Octane boost to prevent detention, which is already accounted for, is doing nothing but giving peace of mind and donating $$$ to nulon (or other octane boost makers).

All speculation on my behalf of course.

Following my reasoning the time to actually add octane boost is the cold days/nights at the strip. Cold air more dense, more O2 per volume would actually lean the tune. Add more timing via intake temp tables and a on "edge" tune could turn to disaster.
I assume these are the reasons why good strips times are had in colder temps, the tune is actually closer "on edge".

Nick, likely Forced Induction throws my assumptions out the window.

[35R]

I guess it depends on how agressive the tune is, your fuel trim situation (if you are running them...) and perhaps the quality of the fuel in the first place (you may want to guard against dodgy fuel)... i would hazard a guess most tunes merely take timing out (based on IAT) but don't add.

[lautray]

Like Nick said, cheap "insurance". We used it in the Monaro on Sunday. Yes air less dense, so richer mixture, but car getting punished to the extreme in the heat, so heatsoak possibly an issue too. Some say don't use it as it detracts from performance, but I will almost always try to use some for added protection. Too much is not a good thing though.

[SSUte01]

Was thinking about the AFR "situation" on hot days,
my assumptions are:- the air is less dense (less O2 molecules per volume) therefore the tune is actually richer (only slightly of course). So I'd assume some protection there. Also the tune is pulling timing due to intake temps as well.
So adding Octane boost to prevent detention, which is already accounted for, is doing nothing but giving peace of mind and donating $$$ to nulon (or other octane boost makers).

All speculation on my behalf of course.

Following my reasoning the time to actually add octane boost is the cold days/nights at the strip. Cold air more dense, more O2 per volume would actually lean the tune. Add more timing via intake temp tables and a on "edge" tune could turn to disaster.
I assume these are the reasons why good strips times are had in colder temps, the tune is actually closer "on edge".

Nick, likely Forced Induction throws my assumptions out the window.


Your logic is scientifically perfectly correct and it took me a fair while to figure out why people always woffled on about leaner AFRs in the heat. The simple reason is that the GM engine management, as good as it is, actually over compensates towards the IAT (on a side note a really crafty US guy successfully trialled equal bias between the IAT and the ECT which helps but GMs complex fuelling algorithms are still slightly out - I also use this method following this guys generosity to share and in my findings it does keep the fuelling much more stable between summer and winter)

So in our LS1 cars even though there is less useable oxygen in the air therefore the ratio of fuel should be increased it isn't. During the heat your LS1 EMS and I suspect other EMS (I cannot confirm this though) will run leaner in the heat and richer in the cold, even with this minimised on my own it is still in vicinity of 2-3% between hot and cold. This is one of the reasons some tuner types prefer to tune during the heat as that is the leanest the car will ever see, rich (within reason) equals safe.

I should add that this is using Speed Density method of fuel management (ie MAFless) a MAF correctly calibrated theoretically should be accurate in any temp however temp can affect resistence and this can skew but not to the same point potentially as SD fuelling.

Cold temps should net superior ETs simply because of cooler intake temps will allow cooler combustion temps and optimum spark timing and there is more oxygen available to use means more fuel to pack in and therefore more power - kinda like nature's nitrous ;) Probably a poor explanation but that's is how I understand it

I hope that made sense

Cheers:)
Luke