Has anyone used regular gas in their G37? If so, was there a problem?

 

The engine will blow up.


.



.


.



.



.




.




.




.




.


.

So long as the car is not tuned to run on premium, you'll be fine. Performance might decrease slightly, but then again, at these fuel prices I doubt you're running it hard anyway.

 

The effects of using a fuel with lower octane rating than recommended by the OE will increase carbon buildup on the valves and increase the varnishing by your motor oil as a result of a less than perfect combustion. While the knock sensors in the last 2 gens of the G are fairly nice, at least put a bottle of fuel injector cleaner in the last fill up before an oil change to ensure some more peace of mind.

Using lower octane fuel may also lead to the fuel level sensors getting vanished and thus relaying different fuel levels (ever been stuck on half a tank for 200 miles?). There's a resistor that the fuel pump reads to get a level for fuel level, which also helps calculate the vehicles fuel and fuel tank pressure levels.

Overall short term: not too much other than you will see lower MPG unless you are strictly a highwayman. you will see lower MPG with constant stop and gos because your getting just that much less power from each combustion cycle.

Overall Longterm: instead of seeing your car get to 300k+ miles without ECM issues, you can always have something looming giving a random reason to replace something. Maybe you get lucky and your cats never need replacing, maybe using cheap **** gas your cats start to smell like rotten eggs sooner, maybe you dont have cats?

At the end of the day, how you drive impacts this question more than anything, if you like the speed and power of the vehicle from stop and gos, stick with 93.
If you are cheap, have liability only and dont have OE recommended tire SIZE AND SPEED RATING, then go ahead and put 87 in it. Garage it while prices are high and drive something else, or sell it if you cant afford to drive the car the way its meant to be driven.

 

The G is factory tuned for 91 octane fuel, not 93. Higher octane gas won't hurt, but it won't help either. It will just cost you more for no purpose.

 

I got a few stations around in the sticks near by that offer the good stuff, but yeah, just run what oe recommends, 91 or better.

 

Where is.... telecomansomethingorother. I recall reading lots of posts from him running strictly 87 octane fuel for extended periods with no ill results. I'd say I ran 95% premium in mine with the occasional 87 tankful here or there. I didn't beat on the car nor drive it aggressively/at high rpms. I couldn't tell the difference. If your ecu has been tuned for particular octane, then you should follow the advice of your tuned and use appropriate fuel.

Generally, I put so few miles on the car that the added cost of premium wasn't much of an issue. If yours is a daily driver, the $5+ can definitely hurt.

 

I'm still here on my third Infiniti and still using regular 87 octane since December 2005 when I purchased my 06 G35 6speed. My current Q70 runs just fine and I get excellent MPG on road trips.
My visits to gas stations are numbered as later this year I'll be charging in my garage.



It will be interesting to see how long the premium users stick to it when it reaches $8.00 a gallon?

 

Never used premium, just 87 octane and drive hard every day.

 

My guess is, higher octane is probably specified to account for edge cases - Driving hard / higher rpms, high altitude, hot temps, etc.

Probably zero to no benefit with gentle highway driving.

 

So after monitoring my logs I found that my car sees "knock" on a 75% + throttle on 3-4th from a low RPM which Is ok or understandable to me. This can be tuned out however this same knock value increases quite a bit more on 87 and 91 octane.

This means that the engine will retard the necessary timing for you to be "alright" however this also means that if this "knock" never registers the ECM can keep timing at it's best number which lastly means it will keep the best power across the band.

Running 87/91 will mean lower performance above 50% throttle, many times the driver might not feel these because they're worried. You can confirm this in the dyno.

 

Thank you for the information. With gas the way it is now, I gave up on running ~90 (mix regular and 93) and run all regular now.
Not sure if it's in my head, but I do feel some power loss when overtaking or the like. No discernable difference at low rpms / highway.