Highest Octane For Stock ECU??

semtex

Whatever, forgive me if I don't take your word for it. In any case, this still disproves the claim that race gas produces gains only if cars are modified.

__________________
"There are no small accidents on this circuit." -- Ayrton Senna
316.8whp & 248 ft/lbs (Dyno Dynamics) | 319whp & 256 ft/lbs (DynoJet) (04/23/10)
Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

Mercennarius

Its not the octane that makes the difference though. You only need high enough octane to resist preignition, anymore can't help you.

import111

Then why with the oxygenated fuel does the car run a lot leaner?

semtex

And how do you know this definitively? How can you be 100% certain that higher octane didn't account for at least some of that 14whp gain? Understand, I'm not saying you're wrong. What I'm saying is that I don't know for sure one way or the other, because I have yet to see any proof. I just see a bunch of people making claims, but I see no tests to verify one way or another. What I'd like to see is a video similar to the one IP did, showing someone dumping in non-oxygenated 100-octane fuel in. If the dyno reads 0 gain, then I'll be convinced that higher octane doesn't do anything, because that's actual evidence/proof. Let me put it this way. I wouldn't accept someone's claims that mod xyz produces huge gains without seeing proof in the form of dyno results. I doubt many of us would, right? So likewise, I'm not going to accept anyone's claim that xyz produces zero gains without the same kind of proof. As far as I'm concerned, until there is proof one way or the other, the question hasn't been definitively answered and all positions are conjectural. Also, just to be clear, I did not post that video with the intent of offering it as proof that higher octane produces gains. We obviously can't say that because the fuel they used was oxygenated. My intent was only to refute the claim that race fuel in general will produce no gains in the 370Z unless the car is modified for it.

__________________
"There are no small accidents on this circuit." -- Ayrton Senna
316.8whp & 248 ft/lbs (Dyno Dynamics) | 319whp & 256 ft/lbs (DynoJet) (04/23/10)
Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

ZzzZz

That's the question though, where is the sweet spot between 91-94? Why pump 94 when you can save money with 91 right?

Was never suggesting 100octane+ is beneficial for a stock 370z.

kannibul

Oxygenated fuels increase the burn rate. It's like adding a (weak) supercharger, and because the ECU is reading off the Air Flow Sensor on what's coming in, and is reading the o2 levels going out, I'm sure it's trying to enrichen the A/F ratio, which would in turn add more fuel and oxy-fuel, making the problem "worse" - I'm sure after a certain point the ECU wouldn't know what do to and just use it's default (rich) map to protect the engine...it's basically as if the fuel injectors are shooting in pure o2 out of a tank into the chamber, in a sense.

You get the same result by using nitro-methane...though, don't go buying R/C gas and sticking it in your Z.

ZzzZz

I don't think members on this site believe on an absolute level that high octane always equals higher power. It's not always the case.

But when your talking in terms of going from 87 to 93 for your 370z, your "equation" actually does apply.

kannibul

Going from 87 to 91, sure with OUR cars and others that recommend 91 octane per manual...

Going from 91 to anything above it, snake oil.

Shunya

well is it a bad thing using 94 octane? why should fuel lower than 94?

my mechanic told me that my engine requires me to use 94octane.
after internal work had been done.

kannibul

What internal work did you have done?

Shunya

I'm gunna try to list things on the back of my head now..
1.8L>2.0L Bore, Camshafts, Cam Gears, Pistons, Rods, Valve Springs, Fuel Pump, Fuel Rail, Injectors, Port Matched, Port & Polish, Ecu.... etc...
too much to list on my track car.

Izzoh

It's not a bad thing. You said you did internal work which probably raised your compression ratio that rasied ratio usually will cause a car to Ping (detonate) running lower octane (87,89,91) rated gas. Running 94 will allow you to take advantage of the mods that you did to your engine by tuning.

Higher Octane dosen't increase HP/TQ it just helps to keep Pistons from coming out the side of the block or through the oilpan by helping reduce Knocking and Pinging. Tuning is where you get your HP from.

Izzoh

That would raise your compression def. over what 91 would safely let you handle. How high where you reving and what compression where your pistons ?

kannibul

Sorry, I thought you were driving a Z.

What do you do if you can't get 94 octane?

Why go to 94 octane unless you're running 12:1 or greater compression?

Izzoh

I think she drives a type R or has a type R swap those are 11.5:1 from the factory so giving that list of internal work I'm assuming it's been rasied to the 12:1 or higher. Most that I know go 12.5:1 on their B-series if they're sticking to NA.