Hi everyone

I have a question about horsepower. From what I ve read the stock hp of a 1974 260z is 139? On my 260z the plate under the hood says hp is 167 or 169. Whats up with that?

Thanks Chris

doesn't it have anything to do with the net hp at the wheels and the engine?

coz I also thaught that it has less than 169!?

maybe it was a secret that time when buyers went to buy those cars at the showrooms and the scandal showed up later on:D (joke)

Maybe you mean 162? Here's a 260Z plate. And to answer BuDavid, Datsun didn't use net hp ratings until the 1979 model year.

Ok 162 but why?

Ok 162 but why?

I think I answered that in my last sentence of my last post. 162(gross) vs. 139(net) in other words, prior to 1979 they were rated at the flywheel after that they were rated at the rear wheels.

Oh I see. 162 sounds better to. I dont know what my hp is since i put the 72 carbs on and a 6-2 header.

Another example would be a 77-78 810 (L24E engine) is rated at 154 hp and my 79 810 (same engine) is rated at 118.

Net ratings are not at the rear wheels, they are also at the flywheel. The difference is that gross HP (the higher ratings) are for a bare engine - no accessories of any kind. No alternator, no air cleaner, water pump, air pump, and a straight pipe exhaust. The net HP is with the engine configured as it was installed in the car - stock exhaust, airbox,, all accessories installed and working.

So if I took all that stuff off my car 162 would accurate? Not to change the subject but how much hp can i gain from adding a cam?

The higher Hp numbers were taken from an engine on a test stand , no water pump, or alternator , no fan, no smog pump , no air cleaner, . Just the engine and the test was run and that is how the numbers derived at . This is how all cars were advertised . Then things changed and the numbers were taken from he rear wheels. Adding a cam will change the RPM where the engine will make its HP , but you will also need to increase compression , milling the head, add headers and new exhaust out to a 2 1/4 or 2 1/2'' . This will help the engine breathe. Alone the cam wont help that much . These engines were tuned at the factory . To improve the HP requires changes. This is all a balancing act , one thing is dependant on the other . Lower the gearing ratio in the diff will give you performance for a lot less cash. Just changing from your 3.36 to 1 gearing to 3.54s from a automatic car will make a difference and you will still have a car you can drive on the Freeway at speed. Gary

Hi Guys:

I believe that there is great misunderstanding of the series of

events that resulted in the current SAE Net HP rating system.

It is not a matter of Gross HP vs SAE Net HP. Didn't happen like that....

These are three different rating systems.

Gross HP

SAE HP

SAE Net HP

Nissan used SAE HP ratings for our 240-Z's. It's not Gross and it's not Net.

The L24's were rated at 150/151 SAE HP, and when measured at the rear wheels

the average 240-Z will put down between 112 and 118 HP.

Where you see large differences in reported HP - you are usually looking at the difference between California cars and the rest of the US. California had stricter emissions standards than the rest of the US for several years during the 70's and early 80's. (remember that L28's in California got Cat.'s when the rest of the country did not have have them etc.)

FWIW,

Carl B.

Carl Beck

Clearwater, FL USA

http://ZHome.com

Yes and now the society of automotive engineers (SAE) is updating the system to measure hp and so every will change