Hi all, first off my first post is going to be pretttty embarrassing. So my first car is a 04 350z. I've been ****ing putting 89 in it this whole time (10 months). I only put 1 tank of 93 in it. I see the other threads about this but I don't see anyone answer the question that I'm thinking. People are saying that there will be a loss in performance, they are saying that because I'm just running it on 89 right? Or do they mean running 89 causes the engine to just not as perform good forever? Also, once I start running 93 I should reset my ECU? Yes? Anyway thanks.... oh yeah, my car runs fine, no spark knocks or anything.

 

No permanent damage, or anything of that sort.

Modern engines will retard timing to keep from knocking on lower octane fuel. You can run down to 87 safely but it is definitely not recommended. If you get bad, low octane, 87 maybe 85 or so it could cause damage. By retarding timing it will reduce power so running 89 might have reduced performance in the short term.

You only need 91 for optimal performance, and a ecu reset is up to you.

Welcome, sounds like to have a lot to learn about cars. Read through the sticky threads if you are interested. Also next time try and search the forum for answers this question has been answered before. I think there is a whole thread on running 87 in the Z.

 

87 only whrn 91+ isnt available. It clearly says "premium only." Cant afford the extra .20 for gas, shouldve bought a different car...

 

ah okay right on. So what your saying is once I put 93 in it I will see the full potential of the car performance wise? Or do I have to reset the ECU to THEN get the full 93 octane performance. Also would resetting the ECU make the timing and everything run right for 93? Do you understand what I'm trying to say?

 

Yeah, I only found that out tonight. Money is not the issue

 

Run the tank low on fuel, fill up with 91 or 93, then after driving it for a bit to get what was in the fuel lines out I would reset the computer so it can relearn the base maps on good fuel.

Not required but it won't hurt anything to do it.

 

It says 91 recommended not required in the manual, but I do agree with you.

This; The ECU will relearn the base maps on its own but resetting it should speed up the process.

 

Im 90% sure that theres a sticker on the fuel door that says "premium unleaded only"

Around me, premium is 91.

 

Yep there is.

 

Wait are you guys serious? I filled up with diesel today is that bad?

It was ultra low sulfur

And it was in the turbo buggy






F650

 

As rancor said, no damage usually ensues as modern engines - even back to the '80s and '90s - can tolerate short durations of bad gas thanks to the miracles of electronics.

The knock-sensor listens for ping and tells the ECU what's going on inside; then the ECU adjusts timing accordingly to run at the highest efficiency the engine can go without suffering.

Long n' short... Degraded gas, degraded performance. Best gas, best performance.... To a point. (Does not mean that running 101 av gas is going to help performance that much more.... too many other factors chime in at that point.)

 

Depends.... how much did you drink?