I was curious if it is okay to fill up with 89 and then fill up the next time with 93, and then doing this in a repeated pattern. Just curious.

 

I know in the manual for the G35 Sedan (and I would assume G35x) it says you CAN use 87 octane, however that gas mileage suffers, and you run the risk of pinging or detonation (can't remember which!)

2004 G35s 5AT DG/Graphite/Premium/Huper Optik Tint

 

Gas mileage does not suffer.

Read this post for more info.
https://g35driver.com/forums/showfla...llapsed&sb=5?=

04 6MT Coupe
35% Madico smoke tint /CF Hood /Injen Cat-back

 

I tried and started pinging, so gas mileage did SUFFER!

"What if there is no tomorrow....There wasn't one today!!!" Bill Murray
'04 OB/GL Prem.Pkg./Sport.Pkg/Splash

 

I have not noticed any pinging on my car on the rare occasions I have put in 87, I usually use 89 or 91(highest available in CA).

I am curious on those who have noticed pinging, is it 6MT or 5AT. The last car Legend required premium gas too but I have run sometimes 87 without any problem or pinging as well. I did although noticed pinging on my Accord and that only required 87. One difference though that it was Manual. I am wondering if manual vs Auto has something to do with the ECU to be able to effectively compensate for the pinging.

2003 G35 Black Sedan

 

You probably won't notice pinging, as the ECU will retard the timing to prevent it (reducing power and economy).

I've been running 87 for a couple of months now, and there doesn't seem to be a noticeable loss in power or a noticeable loss in fuel economy.

NOTE: This is for the sedan, not the coupe.

 

ryoken-but how hard are you pushing the car with 87? Have you noticed the drop in mpg (in other words, whats your mpg with 87) thats supposedly associated with switching to 87?

2004 G35s 5AT DG/Graphite/Premium/Huper Optik Tint

 

I did use 87, not 89.....and you could notice. I've tried 89, but didn't want to after pinging a 87.

I only use 91 after my exp.

"What if there is no tomorrow....There wasn't one today!!!" Bill Murray
'04 OB/GL Prem.Pkg./Sport.Pkg/Splash

 

<blockquote><font class="small">In reply to:</font><hr>

how hard are you pushing the car with 87?

<hr></blockquote>

Look at my sig banner. That's me autocrossing the car. That's about as hard as you can push it.

I normally get about 14-16mpg, with 87 or 91 octane, in spirited city driving. My wife gets about 18mpg when she's the primary driver for the whole tank. I don't have enough highway miles at 87 yet to comment on any changes there, but the initial impression is maybe 1, possibly 2mpg less... at which point 87 is still cheaper in dollars per mile at SoCal prices. I started running 87 a couple months ago as an experiment to justify the extra cost of 91.. and so far I can't.

The big problem is, even with the same gas from the same station, I get +/- 2mpg on any given tank of gas.. so I've been using the Nav's fuel economy tracker to try to establish a pattern. Now that I've run enough 87 through the car, the range still seems to be pretty much the same as with 91. Of course, maybe it's just that California 91 with MTBE sucks as bad as 87.. maybe I could get better power/economy with non-MTBE 91 or 93, but non-MTBE is hard to find and 93 is impossible here. It's not an exact science.

 

Is the ECU different with a 5AT coupe, vs. the sedan? Becouse it does ping at less the 89 octane, at least on my car.

I wonder if the ECU reset effects this?

"What if there is no tomorrow....There wasn't one today!!!" Bill Murray
'04 OB/GL Prem.Pkg./Sport.Pkg/Splash

 

The coupe is different than the sedan. Part of the 20hp difference is the ECU timings. If you look in the owner's manual, you'll see that 91 is "recommended" for the sedan, but "required" for the coupe. It says that you can safely run 87 in the sedan, but should only do so in emergencies in the coupe, and top it off with high octane as soon as possible. YMMV.

 

Ryoken,

It is strange that you've mentioned MTBE. I recently discovered that I can usually go about 25 miles longer on the tank filled with 76 brand 91 octane (no MTBE) than the same 91 octane from Chevron with MTBE. The best was 91 octane from Sunoco, that yielded 50 miles more per tank than Chevron.




***04 G35s 5AT/Sport***
***04 Volvo XC90 T6***

 

ryoken,

Does the manual actually list octane values (i.e. 91, 93, 87, 89?) or does it simply mention premium is recommended for the sedan and premium is mandatory for the coupe? I don't remember seeing the use of specific octane numbers, but I could be wrong.

The reason why I'm asking is that I have a sticker on the inside of my gas cap that says "Premium fuel only" (or something to that effect). My premium octane rating in Florida is 93, and I can purchase Regular at 87 or Unleaded at 89. I know the premium rating in CA (and some other states) is set at 91, so I'm just curious as to the ACTUAL recommendation.

Self proclaimed member of the 300bhp club!

 

I only run 91 now, thats the highest we have here, that I know of.
I tried it 4-5 refils ago with about 2-3 gallons of 87....Oh baby let me tell you! 91...no problem!

"What if there is no tomorrow....There wasn't one today!!!" Bill Murray
'04 OB/GL Prem.Pkg./Sport.Pkg/Splash