Building A L28 (Na)

[TheCrazySwede]

goal is ~ 200hp at the flywheel - what's that ~ 185 at the wheels ? what are you doing about the rest of the drivetrain ? the 280zx close ratio 5-spd & the R200 3.9 rear diff really wakes up these cars. If your CR is > 10:1 i would watch out for ping.

Yup, that's my goal. According to Eiji, I'll be going past that goal in wheel horsepower, so I'm not complaining!

[Travel'n Man]

Naturally once you get that O2 sensor and gauge you will want to know where your oil temp is too.............does it ever end?!?

[TheCrazySwede]

Naturally once you get that O2 sensor and gauge you will want to know where your oil temp is too.............does it ever end?!?

[John Coffey]

208 hp at the crank is attainable with a stock internals L24, 9.5 to 1 CR, running SU carbs. 200hp with Weber 45s and a good cam on a N42/N42 combo is easy. My BSP N42/N42 L28 build made 181 hp at the wheels with SUs and a stock cam. You can even keep the dished pistons.

This formula has been discussed for 15 years over on Hybridz. Its nothing new or nothing special.

[Travel'n Man]

How many HP does a person loose from the crank to the wheels? All the Dyno results that I have seen recently are to the wheels..........

[John Coffey]

Anywhere from 10 to 30%. The numbers are not directly comparable. Some of the better chassis dynos are very repeatable but none approach the accuracy of an engine dyno that is certified to either the SAE, JIN, or DIN specs.

Edited October 9, 2014 by John Coffey

[LeonV]

How many HP does a person loose from the crank to the wheels? All the Dyno results that I have seen recently are to the wheels..........

Every dyno result you see is likely from a chassis dyno (to the wheels), unless it was on an engine dyno (e.g. Rebello).

It's also completely useless to compare numbers from different dynos. Extrapolating "crank" numbers from chassis dynos is equally useless. I've seen as much as 50-60hp swings from the same car, with absolutely no changes made besides it being on a different dyno. A good example is an FC RX7 that came through our shop and pulled 125whp. At another dyno, it hit 175hp. That's a 40% difference!

Edited October 8, 2014 by LeonV

[TheCrazySwede]

How many HP does a person loose from the crank to the wheels? All the Dyno results that I have seen recently are to the wheels..........

My stock 280 with EFI got 145whp. I would assume that would make it 175 @ the flywheel? That would make it a 11% difference.

[TheCrazySwede]

Updated the post with new pictures.

[Zed Head]

Serious looking pistons.  Must be planning some high valve lift.

 

Post 70 and 80 say stock stroke.  Do you know why he had to massage the oil pan?  Just curious.

[TheCrazySwede]

Serious looking pistons.  Must be planning some high valve lift.

 

Post 70 and 80 say stock stroke.  Do you know why he had to massage the oil pan?  Just curious.

 

Not entirely sure what happen to the oil pan. Maybe the previous owner threw a rod or something.

 

The rods are longer, but the pistons are shorter. They are both, also, very lightweight, which should help a lot

[Zed Head]

I see.  It came that way, previous damage.  I started in the middle of the pictures.  Looks like your damper was going bad also.

 

Do you have specs. on the engine.  CR, valve lift, final displacement, etc.?  I saw the general stuff but no numbers.  The valve relief in those pistons has to lower CR.  Just wondering.

 

Looks like he's running 0.54 mm (0.021") "pop-up" on the pistons also.  There was just an interesting thread on that a few days ago.  Thanks for posting.