L24 horsepower

[Carl Beck]

Originally posted by Bambikiller240

YES, 151 HP is GROSS with nothing attached to the engine.

NO, kmack's figures are at the rear wheels as he indicated in his post.

Hi Guys:

Carl S. and I rarely disagree... I have however done quite a bit of research in this subject of HP and HP Rating Systems over the years. I can only tell you what I found..

If you look at all the Nissan publications they quote "SAE HP" of 151 or 150 for the L24's. That is actually different than either "Gross HP" or "SAE Net HP" ratings.

"GROSS HP"

When manufacturers were playing the gross HP game - anything went. The goal was to see just how much HP an engine could produce on a chassis dyno. I have pictures of the Chrysler Hemi's in the very early 50's with their exhaust manifolds glowing red hot on the dyno.'s. No accessory losses, high octane fuels, engines that literally melted down on the dyno after one high RPM pass at the numbers. There is no "standard" by SAE for "GROSS HP" ratings.

"SAE HP"

With the advent of Emission Controls mandated around 1965, and the further refinement of the laws around 1968 the SAE set a "draft standard" to at least attempt to standardize HP testing and the measurements of emissions at various levels of engine operation. That is what the "SAE HP" number is. Basically it called for a regular production engine to be pulled off the assembly line at random, taken to the dyno and feed regular pump gas (what ever was recommended by the manufacturer). The engine had to have all normal and average sub-systems to support engine operation - such as oil pump, water pump, fan, alternator in place.

"SAE NET HP"

With the further refinement of the Federal Testing Standards for emissions, the SAE refined their "draft standard"... and that became the final "SAE NET HP" testing procedure required for use on the 1974 Model Year cars for the US. The "NET" standard included the requirement for air cleaners to be in place as well as the full exhaust system. Additionally all normal and average accessories found in that model car had to be supported by the engine. (The reason for the full exhaust system was because the EPA sat the test measurements for emissions at the end of the tail pipe).

For example if you had a Old's Cutlass in 1969 rated at SAE HP - then you had the same model car rated at SAE NET HP in 73, you would have seen a significant drop in rated HP. (in some cases over 40% less) The reason is, that in addition to the losses from lower compression emissions engines coming on line in 72/73 from GM -the "average" Cutlass had A/C, Power Steering, Power Brakes, Larger Alternator capacity all of which added greatly to accessory loss on the "average" regular production engines.

With the L24's there isn't much difference between "SAE HP" and "SAE NET HP" because the 240-Z's didn't have any optional accessories that had to be added to the "average" engine. Only the air filter and full exhaust system had to be added.

The stock L24 has a pretty efficient stock exhaust manifold to begin with. Indeed adding headers to an otherwise stock engine - produces no measurable HP gain. Dyno runs with the air cleaner top and filter removed show a gain of about 5 to 7 HP. Opening up the stock exhaust system - to a free flowing system - 2.25 or 2.5 inch diameter pipe - picks up an additional 8 to 10 HP. (by the way this is the most HP you can get for the least money on an otherwise good running L24).

So as a guess - if you started with 150 SAE HP - took the above gains outlined above away to get to NET HP... you'd get 133 to 137 SAE NET HP ratings..

Inversely - if Nissan had rated the L24 in a "GROSS HP" manor al la 1950's - with an OHC in-line six cylinder engine of 149 cubic inches, high octane fuel to support timing advance and a 9:1 compression ratio ...IMHO a GROSS rating of something closer to 165HP would have been easy to obtain and reported.

Nissan did not use "GROSS HP" in their reporting.. they used "SAE HP" and they specified that honestly at the time. From 1974 forward, Nissan like everyone else had to use SAE NET HP procedures.

FWIW,

Carl

Carl Beck

Clearwater,FL USA

http://ZHome.com

[zeiss150]

Wow I started this post in December of last year! So here is an up date on my 72 L24... I't blew up! I had to do a total engine rebuild. When I had my E-88 head rebuilt the rebuilders messed it up and it "poped" a valve seat. If you didn't know that is really bad for an engine:stupid: So since I was doing a rebuilt, I figured, what the hell I'll go for it and I jumped up to and L28 N-42 combo with headers 2.5 inch exaust, dyno max muffler, SU carbs with SM needles, K&N air filter, Electronic dizzy, performance cam and valve train in my N42 head. Now I still haven't had it dyno'd but I can tell you that It feels way faster than my L24. Oh yeah I also bored over the engine .020, and had the entire rotating mass ballanced, right down to the clutch pressure plate. I figure that If a stock l28 was producing 142 at the rear wheels then I should be close to 175 HP at the RW. If I close my eyes click my heals together and hold my breath maybe I'll get 180 RWHP. Anyone think I'm smoking crack!!!?????

If anyone has my set up and has had it dyno'd I would love to see the results. Thanks for the interest in the post guys!

Rock on Z people!

Matt-

[HKSZ]

Does anyone know the Gross hp nissan plated to the 280C (single carb) or the 280ZX fi ?

Just wondering because if I was to register a 240Z with a L 28 at Vic Roads will they make me get an engineers report because of the 10% capacity increase rule.

Steve

[Gee]

Like someone from Vicroads would know it's a 2.8!!

If you want the lower output of the 2, I'd go the 280C - asthmatic head, single carb.. blah blah blah.

[Gav240z]

My sentiments exactly my insurance company has no idea about the L28 on my car or the bigger valves, cam , electronic ignition. There's just no point telling them, they will charge you more and i doubt for a second anyone would know who isn't into Z's or Datsun's.

L24 L28 it just looks like another engine number.

I only told them the obvious the wheels and exhaust.

Vic roads wouldn't know any better either.

[zeiss150]

Well the L28 On a 79 and up 280ZX had Net RWHP of 135 because of all of the smoge regulations in the US. The 78 and earlyer 280Z brough 149 RWHP (net). Here is a link http://www.edmunds.com/reviews/generations/articles/100641/article.html

So the real plan should be to take All the smoge "crap" off an L-28 and spend some money on some modes and hold on for the ride.

Rock on Z people!

Matt-

[kmack]

Originally posted by zeiss150

So the real plan should be to take All the smoge "crap" off an L-28 and spend some money on some modes and hold on for the ride.

That's EXACTLY where I'm headed next!!! But, :tapemouth don't tell anyone.... especially the Mustangs!:classic:

[gramercyjam]

Originally posted by beandip

the large 21/2" plumbing will loose you low end power and torque.

Thats what I keep hearing too. That isn't my experience.

[zeiss150]

Does anyone have RWHP specs on my engine build up? A link would be good, or another site member... anything???

Phred? do you have any info?

How about you bean dip?

Rock on Z (and Zed) people!

Matt-

[HKSZ]

From those figures a L 28 could be seen as compairable to a L24 in hp given smog junk.

With Vic roads its a lottery who you get. I changed to a 2lt in my 1600 race car, rocked up to the inspection 3.5 camber, twin webers, race seat, stripped interior, climbed out of the rollcage looking at the inspector thinking I haven't got a chance in hell, but he just lifted the bonnet checked the new numbers said nothing. sweet.

[Carl Beck]

Matt wrote earlier:

>Well the L28 On a 79 and up 280ZX had Net RWHP of 135 because of all of

>the smoge regulations in the US. The 78 and earlyer 280Z brough 149 RWHP

>(net). Here is a link http://www.edmunds.com/reviews/gene...41/article.html

Hi Matt:

First - I'm sorry to say that who ever wrote that article - really didn't know much about the Z Cars. Way too many factual errors there.

Second - he reports 135 HP ... not Rear Wheel HP.

Matt Wrote.. later...

>If anyone has my set up and has had it dyno'd I

>would love to see the results.

I have an L28 bored 0.020 over, Euro Flat Top Pistons (+2cc's), Nissan Cam Kit, 72 E-88 head with 280Z valves un-shrouded, Uni-lite ignition, triple Webers (40DCOE's with 38 chokes), static and dynamic balance...

Admittedly neglected.. not "fine tuned" for years.. but running "OK". I took it to a local club's Dyno Day. There we ran about 15 cars for the day on a Dyno-Jet (Tampa - almost at sea level).

Car #1

Pure Stock 77 280Z with 115K miles, well cared for and

well tuned.. 119 RWHP (a good baseline for the dyno and day)

Car #2

Rebuilt, 76 280Z with every type of bolt-on available.. 121 RWHP

This car had larger throttle body, headers, MSD ignition, rising rate fuel regulator, K&N air filter, free flowing exhaust... etc. It had been driven about 3K miles after the rebuild. (shows the difference in quality between a factory engine and rebuild by most other shops)

My car ..... 139 RWHP With a fresh tune, I'm sure we could have picked up a few more HP... but nothing drastic. Might have got it up to 145 at the rear wheels. (that's about 175HP at the flywheel if you use 20% driveline loss).

At one time I had the dyno run sheets for the above, somewhere on the server - but don't see them there now. I'll keep looking..

If your looking for streetable performance today - and want to stick with the in-line six -the ONLY way to go is with the L28 Turbo.. running 11 lbs of boost or less.. it's pretty easy to get 250 RWHP .... You won't get anything close to that on street gas running under 10.5:1 compression in an naturally aspirated engine.

FWIW,

Carl

Carl Beck

Clearwater,FL USA

http://ZHome.com

[Carl Beck]

Earlier I wrote:

>Dyno runs with the air cleaner top and filter removed

>show a gain of about 5 to 7 HP.

Correction.. oops.... now that I review the dyno sheets... that should be 3 to 4 HP gain with the stock air cleaner top and air cleaner element removed (you have to leave the air cleaner base on because it contains the air horns).

See: http://ZHome.com/rnt/Dyno/KThomasHeaders.htm

sorry..

Carl

Carl Beck

Clearwater, FL

http://ZHome.com