Stock HP dilemma

[Guest d9]

At http://datsunzclub.net/datsunzcarhistory.html.html there is a history of the Z cars with all the changes made over the years. Very interesting site but it has left me somewhat perplexed.

 

It says that the 1977 N/A had 170 HP. It also states that the 81 N/A had 145 HP and the turbo had 180 HP.

 

I posted this finding on another board and asked the question "can this be right?"

 

The answer I was given was...

 

"The 170HP figure is correct but back then they stated gross HP (at the flywheel). Starting sometime around 1979 they stated HP as net HP (at the wheels) which is 25 to 30% less due to drivetrain losses. E.G. my HP rating on my '79 is 132 even though it makes just as much or more HP than a '77."

 

I am unable to find any info to support this. I find it unlikely that the ZXT was only 10 HP stronger than the 77 N/A but those are the specs on the data plate in my (soon to own) 77, in fact it says it's 173HP stock.

 

How can I confirm this? I really hope the ZXT and the Z n/a are using different measuring points for the HP rates.

 

Can anyone help me out here?

 

d9

[Guest Aaron]

My understanding is that those numbers are correct.

 

They started using Net HP in 72 if I remember correctly.

 

Both Net and Gross HP is measured at the flywheel, however net HP measures the engine as it will sit in the car. All accessories, manifolds, air filters, and exhausts are connected and working. Gross HP is measured without accessories, exhaust or air filters.

 

I think the ZX was down in HP because of emissions and fuel economy requirements. With it's electronic FI, instead of analog, it was supposed to be much more reliable, more efficient, and provide better torque.

[Guest d9]

So if I were to compare the ZXT to the 77Z it would be at about 234 HP (180 + 30%) compared to the 170 HP of the N/A 77Z right?

 

Or the 77Z would really translate to about 119 HP (170 - 30%) compared to the 180 HP ZXT.

 

That sounds allot better to those of us considering a ZXT swap "stock" to begin with.

 

Thank You for your reply. You are an asset to the "Z enthusiasts".

 

d9

[Drax240z]

No doubt about it, the stock ZXT engine makes a lot more power than a stock NA 2.8L...

[cygnusx1]

No doubt about it, the stock ZXT engine makes a lot more power than a stock NA 2.8L...

 

I'll second that! 13psi today accidently(yeah right) while I was testing my home made boost control valve is WAAAAAY faster than my 76 N/A motor.

 

Take it from me my N/A motor was stock and my 83T motor is stock (except now I tried 13psi ) ...gotta get an intercooler QUICKLY!!!! Does cold weather make up for lack of I/C?

 

Dave C.

[Tony D]

My N/A L28 EFI motor (76 California System) dynoed at 147hp to the wheels.

Given weight and E.T./MPH most web "1/4 dynos" put the number of my engine at 202hp @ the crank. So the truth of the numbers runs somwhere in between! The plate syas X, and actual applications show something else, but close enough for the "correction factors" everybody is fond of using.

Now the terrible truth is that it's an 81 engine with 186,000 miles in a 75, with a 76 manifold and EFI bits. So is it supposed to have 145HP, or 170? Given my 147 Dynojet run, it's dead on. Given the 170 number for the 76, then you add that "correction factor" and it should be 180something, which is darned close to the factory rating of 170...

 

All that matters is that it runs, and it bests most stock Hondas, eh! LOL