TRSCobra

Anyone use octane boost when they track their GT4 or GTS 4.0? Has it made any difference in performance or MPG?

I'm stuck with 92 octane and wonder if I would see any benefit from increased octane with the higher intake air temps on hot track days.

85Gold

I have run it Boostane on 1Lap when only 91 octane was available. I prefer getting 100 if available and doing a 50 50 mix as a very reputable tuner told me these cars run on the knock sensors so I feel it's good ins. That being said I can't tell you if it makes a performance difference.

Peter

Gabriel@NutCracker

My Spyder spends most of its active life on the Italian island of Sardinia. No European 98 Octane there (that would be American 93 I believe). I use octane booster from Liqui Moly. Do not notice difference in performance vs. the first tank of true 98 I bring with me inside the Sypder's tank (trailered in). But still I can only guess whether the octane booster has any effect or the ECU just compensates for lower octane fuel without me noticing.

BabyNSX

From my experience the GT4 engine doesn't really enjoy 91 octane fuel, but can run on it endlessly without issues due to the knock feedback scheme that is used. When capturing data-logs with the COBB Accessport on the street tune I could see plenty of timing adjustments when running 91 (California blend) fuel that simply went away with better fuel. When tracking the engine is under more thermal stress and more sensitive to fuel quality resulting in more frequent timing adjustments which negatively impact power output.

I haven't typically run higher octane fuel at the track, but will start doing so simply to allow the engine to operate further away from the raged edge w.r.t. engine timing and knock.

beez

The car's ECU is optimized for 93, so going higher than that is a waste of money. Most tracks have higher octane unleaded gas available, so you can mix them together to get what you want. In your 16.9 gal tank, you can put 4 gal of 100 octane at the track, then fill the rest of the tank with 91 (what's most available out in the west) at a regular gas station (usually it costs less than at the track), and you'll get 93. The difference between 91 and 93 does make a difference to the knock sensors, especially on days where the ambient temperature is over 72°F.

My Cayman GTS 4.0 owner's manual says not to run the car at full throttle unless you have 93 in the tank.

In your situation, 92 is so close, I'm not sure I'd bother. But you can still do the routine above, just with less of the higher octane fuel. There's a 93 octane mixture calculator here (https://find93.com/octane-mixture-calculator). I prefer to mix rather than use boosters.

TRSCobra

It was the conversation between Jamie and Charles in the last whiskey Friday video, regarding tuning your car, that made me wamt to consider higher octane. I know the IAT's have to get pretty high on track with the air intakes pulling air off the front brakes and hot asphalt. Would just be cool to see if I could squeeze out a few more MPH on the straights, but I'm not about to spend $80 on 100 octane to mix in with my 92 to find out.

85Gold

I add 100 octane as a safety factor especially in hot weather. A few 💸💸 of insurance seems like a good idea.

Peyer

Josh_357

I’m on 92 here in the PNW as well. I’ve been throwing a little bit of boostane in to get above the 93 threshold. My butt dyno says it helps, and keeps power levels longer on track. No data to prove it though. I might try 100 octane mix though. Looking at it as cheap insurance. Without a lot of tuning I don’t see the need to go above 94 octane by mix or booster.

TRSCobra

Looks like 2 gallons of 100 mixed in with 92 would get me 93 octane. Not terrible, but I could use an octane booster with MMT and get 95 octane with a bunch more headroom.

Maybe I'll mess around with it at the track after a few sessions topping off with some 100 and see if I can notice any difference from lack of knock retard on 92 alone.

Reedy

I used to use it in my turbo car but it kinda fouled the spark plugs in weird ways. If the car is tuned properly for one type of fuel then adding octane booster doesn't really help.

Angryinch

This isn't necessarily true, running a bit higher octane will help once the IAT climb to keep timing up, to a point. Once you cross a certain IAT the ECU will start the reduce power. A little bit of extra octane wouldn't hurt for extra protection/power. The ECU will protect the car and has many safeties built into it. I wouldn't run anything less than 93 octane in these engines. If you run 91, its definitely reducing timing.


I would avoid this stuff, I mean as a last resort sure, but it leaves orange residue crap EVERYWHERE. When I took the downpipes off after using this on a previous turbo car, the turbos were full of this orange residue. I can only image how the O2 sensors and spark plugs will like that. I know M Engineering does not recommend using boostane in their experience either.

TRSCobra

There's been guys on here who've datalogged on 93 octane and seen the ECU pull timing due to knock events when IATs get up there. Which is why I asked if anyone's seen any actual difference on track. I don't expect any "gains" in power from stock, just trying to minimize potential power loss as the heat soaks the intake system from longer track sessions in summer weather.

I'm familiar with MMT octane boosters as I used to run them on my Z06 drag car before I bit the bullet and started running MS109. I had some orange residue on the plugs and O2 sensors, hell even the exhaust valves were orange but there was never any drivability issues from that. I also wasn't running it full time, tank after tank either.

j-dub

Do you have an OBD reader? If so monitor the knock retard during a hard acceleration. If you are getting any, try adding some race gas/octane booster and see if the knock retard goes away.

TRSCobra

I'm bringing a can of royal purple max boost along with a 5 gallon gas can to the track on Thursday. I'll be logging IAT and ignition timing advance if my Bluetooth OBD dongle setup works correctly. Will run a few sessions and check logs, then add the octane booster and top off my tank then log again to see any difference.

I'm used to Hptuners software showing nice graphs and plenty of data, so doing it all through a phone might be tricky, but I'm all about finding out!

Gabriel@NutCracker

This thread got me thinking I should monitor knock retard as well, while running the 91 (95 EU) with octane booster.

Does anybody know whether the cheap generic ELM327 Bluetooth module is capable of this on the 718 platform? What app to use with it? Back in the day of Miata I would use Torque.