I think it's around $35.

Interesting they recommend longer duration oil changes. The only time I would change oil sooner sooner is if it's a new car, rebuilt motor, or I had just purchased a used car.

 

$28 for the standard, $38 if you have them do a total base number analysis (checks the levels of the additives)

 

I have been data logging the HR car more on 87 octane fuel and there is constant knock showing in two bands. It's pretty minor when the knock shows up in the 2800-3200 RPM range but it quiets down until 5000-6000 RPM and it gets more significant. Even though you can't hear the knock doesn't mean it's not there, and ringing your pistons everyday will definitely cause more wear. I think I'll start a dedicated thread to octane vs knock between DE and HR series engines. I think it would be interesting to see when they quiet down from 87oct - 91 oct - E15 - E40 fuels. I know my 05' turbo car on E85 runs all zeros in the knock threshold and is quieter than my stock 2004 G35 on premium gas.

Even if the car was run on 87 octane i'm sure it would make it past warranty which is probably all the manufacturer is worried about. I'm more worried about wear for the long haul since most people in the US push 200k plus on their vehicles. Of course I've seen a lot of 200k+ HR's out there and I doubt everyone is buying premium fuel so who knows how much more wear the knock relates to without testing two cars and pulling the pistons to verify... All I'm saying is less knock or none is better.

 

Not many miles more since this thread but oil consumption is not something I worry about on mine.. dipstick still shows full at all times.

 

My 08 G35x doesn't burn any oil either @ 124k miles.

 

Only thing our G's burn is rubber

 

Only with cheap tires, unfortunately.

 

All this talk about strictly miles driven between oil changes. What about time in service? I have a mandate from my engine builder in my other car of 5000 miles or 6 months, whichever comes first. Since I'll driving the G maybe 3500 miles per year, I'll be scheduling oil changes by date, not miles. Probably 2x per year. Overkill? Perhaps. I just couldn't stomach the idea of waiting 2+ years between changes to reach that 7500 mile interval.

 

It really depends on atmospheric conditions where you live. If you live in a high humidity environment then you should consider twice per year, if you live in a dry environment then once per year is fine as long as it's not sitting for long intervals.

EDIT: Maximum duration is 1 year, don't go longer than that even if the miles aren't adding up.