HP ratings

[deadflo]

Hey I posted this as a follo to the l-24 HP question but I think it got lost in the fray.

Something Ive been wondering about for years. Nissan changed to using net HP numbers in 74 .

Following that, the first 280Z's were rated at 149 HP, but why is the 77 Z rated at 170HP?? Does that engine really have more power? Looks like the same engine as the earlier 280, and the performance specs seem to be the same as well.....

Another question. my71 engine plate shows the power at 150 at 6000RPM. Why do some sources show the 240Z power peak at 5600 rpm??

[ChrisA]

Originally posted by deadflo

Something Ive been wondering about for years. Nissan changed to using net HP numbers in 74 .

Following that, the first 280Z's were rated at 149 HP, but why is the 77 Z rated at 170HP?? Does that engine really have more power? Looks like the same engine as the earlier 280, and the performance specs seem to be the same as well.....

The data plate on my wife's 75 280Z said 170 HP. And I believe the ratings were in GROSS horsepower not NET like they are now. The 280ZX was tagged as 149 hp NET. And I thought there were no changes in the motor when it went from the 280Z to the 280ZX. I think there's a good explanation of the ratings on www.zhome.com.

Chris

[deadflo]

Chris wrote

>>The data plate on my wife's 75 280Z said 170 HP. And I believe the ratings were in GROSS horsepower not NET like they are now. The 280ZX was tagged as 149 hp NET. And I thought there were no changes in the motor when it went from the 280Z to the 280ZX. <<

Interesting Chris, i know that Road and Track listed the HP of the 75 280-Z at 149.

I've seen a reference the 170 HP figure in a 77 article from R and T, and even Brian Longs book mentions the 77 280-Z as having an UPRATED HP of 170.

Also my 79 ZX tag shows 135 HP (net)

I'm curious why Nissan would quote net ratings (SAE) by 74, then revert back to gross ratings after that...

[ChrisA]

Hey Steve, my bad on the ZX, it was 135 hp. I'm 100% on my wife's 280Z, I worked on it so much the tag is burned into my memory. I'm going by the salvage yard this weekend where they have every year of 280Z and some 280ZX's. I'll try and get some more info.

Chris