I've noticed that if I run 87 instead of 93, I actually get worse gas mileage besides the pinging noise. Unless you drive 100 miles every day, you won't save all that much if you put regular octane. I know people that have been running 87 since day one in their premium-requiring cars and have never had a problem, so it's a psychosomatic thing more than anything. Supposedly you can sneak a few more hp with premium gas though.

 

there is absolutely going to be a hp difference. if you run 87 the computer will pull the timing back to eliminate the detonation. less timing = less power - at least for what we're talking about here.

'04 coupe6mt
ivory premium aero

92 plymouth laser AWD
heavily modified for solo II
11.51@118 on 215/55 goodyear eagles

03 dodge ram quad 4X4 Hemi

 

I put in Mobil 91
And definitely change the oil every 3k with Mobil 1 SuperSyn cause of the cold winters and humid summers in Toronto. I am a believer in preventative maintenance.

 

I use techron 87 with bi-tron fuel treatment (octane booster/oxygenator). no pinging or knocking evident. If there were, it's way to small to notice...otherwise I'd need a diagnostics scanner to look up any knock. I did my baseline dyno runs on 87 & bi-tron fuel treatment, resulting in 233rwhp and 222ft-lb tq. The figures would be more if the shop was much cooler and less humid. It was about 90d-95d in the shop and muggy. You'd sweat just doing nothing. I average around 23mpg, mixed city/highway.

I ran my Buick T-Type on techonr 89 & bitron fuel treatment. I had a onboard scanner to detect knock. I would use my 92 race chip (meant to use w/leaded race gas), boost set to 20psi. I would get about 2* knock retard under load at 3000rpm right when the boost kicks...then no knock afterewards. Then I swapped chips to a 92 street chip, left the boost at 20psi. The scanner didnt register any knock. I put 345rwhp and 470ft-lbs tq. I would get around 20mpg mixed city/highway.

My street bike runs on leaded 87 octane race gas from VP called MR9 on racedays. I dont normally run racegas on the street. The race gas is highly oxygenated, meaning it's highly combustable. (I think..that's what I've been told) I made more HP on the 87 leaded race gas vs using 92 premium grade from 76 Unocal. baseline using 92, I netted 107rwhp and 47ft-lbs tq. On 87 Race gas, I netted 111rwhp and 51ft-lb tq.

anyways...just giving figures with the gas i use. [img]/w3timages/icons/smile.gif[/img]


My Sources

 

^^^
What OmahaG said...

2003.5 G35C 5AT
Premium Package
Tire/Wheel Package
K&N Filter, Z-Tube, EGK

 

Just curious about your bike dynos...were they run on the same day? I don't know much about bikes but you never know if maybe that's the reason for different dyno numbers.

'03 G35c DG/G 6mt, full options
clear corners, tint, z-tube/popcharger,
nismo titanium shift ****

 

It is the stock 4.6 liter V8.

I may ask them the next time I take it in for an oil change.

2004 Sedan/DVD Navigation/Desert Platinum/Willow

 

The manual blatantly says to use 91 or above. You can use something lower for a short time if premium is not available.

93 is not going to give you a performance advantage over 91.

-----
Legend in Time

 

The G35 coupe's manual, I understand, explicitely states 91 octane or higher. The sedan (at least through 2004), only recommends 91 octane. It requires 87.

And the question was whether buying anything past what the car requires really makes a difference. In my truck, it does at times of the year.

In the sedan, it may. But I don't know if it really matters in normal driving.

2004 Sedan/DVD Navigation/Desert Platinum/Willow