Question about used 350z's (fuel question)
 

I'm buying an 04 /w 23k miles on it. I'm wondering out of curiosity, what if the guy that owned it before me used regular grade fuel instead of premium, would it effect the longevity of the car for me? I read somewhere that continued used of regular grade can effect the car. This is just something I'm wondering about, not sure what fuel the guy before me used so it just makes me wonder. I hope he used mobile 1 motor oil and premium grade fuel. =) Thanks for any help.

Yes, the use of regular-grade fuel will affect the longevity of the engine. Negatively. The effect of using a low-octane fuel where high-octane is required is detonation, unless the computer can compensate by retarding the timing sufficiently. Detonation can result in piston and rod damage, eventually ending by holing a piston.

The owner's manual is very specific about use of regular fuel on an emergency basis only in the Z. What's stated is to put in half a tank maximum, and top it off with 91+ at the first available opportunity. Nissan doesn't even want you to use a whole tank of 87 even once, which tells me that they are VERY worried about engine damage, and that the computer isn't set up to compensate. So you can safely assume that 23K worth of regular fuel would indeed be not very good for anything.

When you buy a used vehicle, you never know what the previous owner did or did not do. That's the risk you assume.

i hate to say it but my future brother-in-law runs 89 in his 350Z... NEVER runs 91 or higher... he has almost 40k miles and no problems so far...

It is certainly possible but more or less unlikely that someone uses regular gas. In addition, this car still has a powertrain warranty 5y/60k – so don’t worry too much. BTW, this car doesn’t need a specific oil brand.

I never got why someone would buy such a nice car and cant spare the extra $3 a fillup it would take to put premium in it. :dunno:

It is very risky to buy a used sports car, especially an affordable one....

The savings, unless we are talking about buying a shell to build on, are not worth the potential headaches.

Just my 2 or 3 cents !

Z/G Owner:
zzz
Location:
New York
Color:
Silver
Trim Level:
Enthusiast

Congratulations.

going off of what bluespec said... how can you guys buy a 30k plus car. or however much u paid for it. at one point it was worth over 30k. but anyways. buy it then when it comes to putting gas in u cant even put an extra 10 to 20 cents per gallon to get the good stuff which in the long run will help ur car out... ugh... just get premium! u will thank urself later when ur z is still runnin like she should

+1. Regardless of carfax reports or receipts of maintenance, you still are at risk with a used car.

One must weigh this risk vs. the extra cost of buying new, and losing a large sum of money as you leave the lot.

I got lucky. I know the PO of my car, and well he's ANAL. it only had 3k on it...and it lived in his garage....

Anywho...in theory new engine management systems should be able to handle retarding the timing to keep knock down if a penny pinching owner decides to use regular instead of premium....NOTE, i did say "in theory"

vise versa... people who put premium in a car that requires only regular gas is throwing money down the drain.

i dont know about that....one car comes to mind... my dads camry...I drove it alot before the Z...some days I'd run it on regular... it was sluggish, and fuel economy was at best OK... few days I would fill it up with 91+, car worked drove great, no sluggishyness and it seemed to hold the MPG much better... same with a Honda Pilot I drove before...fuel economy jumped like hell. :cool:

how would you know if he did or not? there would be no way of telling for sure unless you develop engine problems. and motor oil brand doesn't matter either, it is a matter of personal choice.

one thing is for sure though, not all gasoline are refined the same. If you put off brand/cheap gas in a vehicle that requires premium, you will feel the difference in performance immediately.

Ouch!!! Just luck I guess. With my luck, I wouldn't chance it.

It wont affect the car at all , and oil , well as long as its been changed you'll be fine.