2 completely different cars

[siteunseen]

This 240Z is a lot peppier than my 280Z. Not as fast but quicker if that makes sense. Could that be the weight difference? Also what grade fuel should I run in the '72 240, highest octane or lower? Stock motor with the dome carburetors. Thanks for any responses. I promise not to flog everybody with questions right away. Sprinkle a few in over time.

[Gary in NJ]

If you're not experiencing any engine knock, then 87 is fine.

The 240Z is lighter and as a result, more nimble. That's probably the difference you are noticing.

[rcb280z]

I ran 87 in my 72 years ago. I also run 87 in my 77 280 with timing set 16 BTDC and no pinging.

[Carl Beck]

I've always ran at least 91 octane - but then I've always ran more initial advance in the timing. As I recall the original owners manual called for high test.. Nonetheless if your set up to run 87.. and you are not getting ping - run the cheap stuff.

FWIW,

Carl B.

[LeonV]

What the manual recommends is equivalent to today's 87 octane.

I use 89 octane in my L24, with as much timing as I want. I suppose I could use 87, but I tuned my timing curve on 89.

[MotoManMike]

Not going to get into octane, Your "peppiness" could be related the the driveline gearing.

[Zedyone_kenobi]

Well wasn't the 240Z the quickest Z until much much later. The added weight was not made up for with HP fast enough. I use to have a chart that showed this. I thought the 240Z was the fastest Normally aspirated Z until the 1990 300ZX. However, I think all the turbo Z's were quicker than the original 240Z

[Carl Beck]

What the manual recommends is equivalent to today's 87 octane.

Had to go check my Owners Manuals - you are correct for 1972 - 87 is for Reseach and Motor average. It was 91 RON in other countries.

The "original" Owners Manuals {69/70} did call for 91 Octane - but back then it was only Research Octane Number..

FWIW,

Carl B.

FWIW,

Carl B.

[LeonV]

Had to go check my Owners Manuals - you are correct for 1972 - 87 is for Reseach and Motor average. It was 91 RON in other countries.

The "original" Owners Manuals {69/70} did call for 91 Octane - but back then it was only Research Octane Number..

FWIW,

Carl B.

FWIW,

Carl B.

Precisely!