I am wondering how much HP I have. I don't have access to a dyno, so I'm hoping someone with the same stuff as me has seen some numbers. Anyway, I've got an N42/N47, with a K&N cold air intake, headers with custom downpipe, and straight 2.5" pipe back to a turbo style muffler with three chambers. Everything else as far as I know, is stock. Thank you.

Tony

 

Probably around 135 to 145 at the rear wheels. This is concidering you have dished pistons in your N47 block. A stock 280Z in my club pulled 137hp at the wheels (carb'd) his mods where K&N intake, custom exhaust. So go from there, The header might net you somewhere around 5hp. This is by no means is acurate, just my personal guess from what ive seen. I have rode in this car and rode in a 260Z that had 194hp at the wheels, and let me tell you 57hp dosent sound like much. but when you take a ride its unbelivable the differnce between the two. Hope this helps.

 

Hey, thanks for the info. I do have another question. Do you know of any quick way to get some more HP? I know some internal stuff will make a huge difference, but I don't have the money to buy all that. Tb's are the other thing I have heard of, but those are expensive upgrades too. Any ideas for a cheap add to hp? Thanks a bunch

Tony

 

Tony, TB's are expensive if you get them from MSA, However go to a junk yard and get on off of a Z31 it will be bigger 53mm or you can step all the way up toa 240SX TB and get a 60mm one. I paid $25. for mine. You will have to open up your intake to allow for more air, I took a rag and stuffed into mine and used a flapper sanding wheel and went round and round till it mached up with the gasket. As far as any other bolt on mods theres not to much left. Save your money buy a later model 280ZX with the F54 block, Refresh it, have your head resurfaced 3 angle valve job, dont worry too much about port and polishing your head. The N47 has the steel head liners not too much you can do there. With the F54 block youll get flat top pistons with your closed chamber head she will increase HP and put the smile factor on your face Hope this helps Josh

 

Change to a lower rear gear ratio. That will make a big difference in your acceleration.

 

This is true ATTWORTH, put a 3.7 or a 3.9 in it

 

3.9 or 4.11 ! ....oh, and a 5-speed transmission if you're running a 4-speed right now

 

hm, never thought of changing my gears. Where would I pick up a 3.9 or 4.11 rear end? I've never done anything to the rear end of anything so I have no clue. It does have the 5-speed. Thanks guys!

 

3.9 rears came in early Z31 non turbos as far as a 4.11 the only two I know about is a old 200sx turbo or you can get the gears out of a old 4x4 pick-up Nissan of course. I don't know which models, mabey some one else knows. I will tell you this, you can go tooo low and it will hurt you. I ran a 3.9 with stock tires and it was just too low, I went from 3.55 to a 3.9 and I thought my turbo would never come in, Not as much drag against the motor.

 

For a non-turbo engine 3.9 or 4.11 is just fine if you are running factory tire size. I actually have heard of other people with a turbo Z going to 3.9 and you're the first one who complained. Maybe they weren't running as much boost...

The R200 3.9 is found in the 1981-83 280zx nonturbo with manual transmission. These are the easiest to find.
The R200 4.11 is found in the mid 1985-86 200SX turbo. The non-turbo 200SX has R180 4.11 but I heard the halfshafts aren't compatible with earlier Z-cars.
With your stock 5-speed, you should probably just go with a 3.9 (the higher the number, the lower the gear ratio) Your car would have a 3.54 right now

 

On a Non turbo I agree this will help you I'd probally go with the3.9. I have only seen one 200SXTurbo ever, and depending on your tranny if it's a four speed I definately would not go any lower. Just my .02Cents

 

Cool. I've heard switching to an r200 requires changing the mustache bar. Does my car have an r200 already or is r180? I forgot how to tell. Thanks guys.

Tony

 

Judging by your engine block type, I would say you have a 77-78 280Z. If so, then you already have an R200. It'll be an easy swap to go to a 3.9 gear.