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Swapping 280Z 4 speed to 5 speed. Parts needed?


MOTORHEAD427

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In case you haven`t noticed,:eek: I don`t know much about gear ratios.

My daily driver has been a 98 LS1 Z-28 for the last 8 years and I love the way it accelerates( 4 speed automatic-I drive it like a manual car though:mrgreen: ) I will get the 280ZX tranny for my 240Z. Question is how do I adjust the gear ratios so that I get a 0-60 under 6 seconds, or is it impossible with an L-24 triple setup like mine?... I don`t know anything about it....All help is appreciated.Thank you...

 

ERIC

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I have triples setup and with the 3.55 ratio first gear and drag radials it launces like a rocket. Driving around town it can easily start out in 2nd if not racing someone. My son and I went out and tried some hard launches the other day in 1st against my 11 second Z06 and he kills me on the launches easily by 3+ cars through 1st and 2nd and then I have to chase him down. So for stop light to stop light or runs through 3rd its damn quick and thats why we wanted the 4 speed with the really low 1st gear.

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Briann510.

I checked your website.

Thanks but your Z is more like a Pro Street race car. That`s not what I`m after.

 

I want a race car that I can drive on the track,street and freeway.I already have the strut and sway bars. Eibach springs and Tokico`s. The car handles well.

 

Mr Mortensen, could you please tell me more about your Z? Gear ratios, engine, all the specs maybe with pictures of your engine? Thank you very much.

 

ERIC

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I don't have very many pictures of my engine, and it wasn't much to behold. I'm not really about making things look good. My car is a 70 with a L28/E31 head combo. Triples, cam, ported head, etc, puts out about 240whp by some drag racing calculators, but I've never had it on a dyno. You might think of it as Brian's motor's baby brother. Mine is a poor man's engine, his is the real deal.

 

The gear ratios for all the transmissions are in this site that I linked to previously: http://www.geocities.com/z_design_studio/

 

I have the 80ZX transmission and I had 3.70 gears. They worked well with SU's but when I switched to Mikunis the gears were a big problem. I am now installing 4.11 gears, but that's just one part of a pretty major rebuild that I've been into now for about 3 years. My car has been on a rotisserie for about a year and a half now, and I'm expecting to take it down just in time to move in April or so. Then I can move it and finish the other 970,000 projects I've got going on it. The car was OK before, should be quite a bit faster when its done. I don't expect to drive it for a LONG time yet. I've been into EVERY part of the car, I can't think of anything that is going to be left as it was before I started. Literally nothing on the car will be untouched...

 

As to your earlier 0-60 question, you can't really "adjust" the gear ratios. You can choose ratios, and then build an engine that makes enough power to get you from 0-60 under 6 seconds. I don't think it will be very hard to do, even with an L24. If you were to get the low geared rear and and the ZX transmission and not be able to meet your goal, next step in my opinion would be to put a bigger engine in it. L28 is 15% larger than the L24 I think, so that is a 15% bump in power that you could expect on a similarly built engine.

 

There is a hell of a lot of information about how to buid a hipo NA L series engine on this site. I suggest you search and read some threads, I know you'll find the info you're looking for...

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Briann510.

I checked your website.

Thanks but your Z is more like a Pro Street race car. That`s not what I`m after.

 

I want a race car that I can drive on the track,street and freeway.I already have the strut and sway bars. Eibach springs and Tokico`s. The car handles well.

 

Mr Mortensen, could you please tell me more about your Z? Gear ratios, engine, all the specs maybe with pictures of your engine? Thank you very much.

 

ERIC

 

Our 240z IS driven on the street, 1/4 mile tracks, road racing tracks and also the freeway frequently so im not sure what you thought our car was used for. It has over 10K street driven/street raced miles on it and about 200+ road track miles and alot of freeway driven also with no problems currently with the Rebello racing engine and it does quite well doing all 3 scenerios. So it is ready for track, street or freeway driving/racing depending on our mood. Correct me if I'm wrong but that sounds like to me what you want your car to be able to do correct?

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Brian.Please don`t get me wrong.

After I watched the Infineon 1/4 drag racing video on your website, I`ve had the impression that your Z was a Pro Street race car.My bad...

I guess I`m going to end up buying an L28 motor and the 280ZX tranny.

Thanks for all the help.

PS: Brian your car REALLY looks like a Pro Street dragster...Especially with that cowl hood:-o )

 

ERIC

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Correct me if I'm wrong, but isn't the 280z 5 speed that same ratios as the 4-speed but with an extra gear?

 

Depending what the car is going to be used for will be the tranny choice for ratios. My son is more into drag racing and stop light to stop light brutal acceleration with large drag radials so the 4 speed was the choice with the really low 1st. even swapping rims/tires its still an excellant road racer also with a top speed still of 125 mph.

 

1st gear is very low for the 240z 4 speed (3.55) and even lower for the 260z 4 speed and if you have the traction both will get you out of the hole quiker as compared to the 280z 1st gear ratio (3.321).

 

here is a breakdown of ratios for 4 and 5 speeds:

 

240Z 3.549 2.197 1.42 1.00 '70-'73

 

260Z 3.592 2.246 1.415 1.00 '74-'78

 

280Z 3.321 2.077 1.308 1.00 0.864 '75-'79

 

280ZXa 3.062 1.858 1.308 1.00 0.777 '8/79-'80

 

280ZXb 3.062 1.858 1.308 1.00 0.745 '81-'83

 

280ZXT 3.500 2.144 1.375 1.00 0.780 '81-'83

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  • 2 months later...

Ok, so I just grabbed a 5 speed out of an 83(I think) 280zx 2+2, everything looks really similar to the 4 speed, the one big difference that has me mildly concerned is this. On the 4 speed there are two sensors(if you can call them that) I know that one is the back-up/neutral safety swithc and the other is the "sensor" for the back up lights. One is at the front, and one is near the rear on the extension housing.

 

On the 5 speed there is only one "sensor" and it's at the front. Is this going to cause any problems?

 

I searched around and couldnt find any info and transmissions(gearing and what not) is not my strongest area of expertise

 

can anyone give me some info?

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Guest TeamNissan

Here is a 80' 5 speed with the closer ratio. Its far from you but its pretty light. Shipping wont kill you on it. I'm sure if you offer him 50 bucks for the tranny he will take it.

 

http://cgi.ebay.com/ebaymotors/79-80-81-82-Nissan-280ZX-Complete-Engine-Transmission_W0QQitemZ190081491912QQihZ009QQcategoryZ33615QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

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  • 10 months later...

i have a 240z-t drift car, im running the stock 4spd, i had a 4.36 rear from a r31 skyline r200, and it was a bit too much, i was drifting 4th gear at mid-ohio, i swapped out to a 3.5 gear from a turbo zx, it still waste 1st and 2nd gear , im planning on a 240sx 5spd swap and seeing how it does with the 3.5, might swap back to the 4.36 if it needs it. 4 spd hangs in like a champ. even with 300hp, wouldent put race tires on it thow.

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  • 4 months later...
  • 4 weeks later...

Back from the dead! I figured that this would be better than making a new thread, since I'm going to be doing something similar. I have a 77 280Z with the original 4-speed MT. The previous owner swapped on a 5-speed rear end, for reasons already mentioned in this thread. However, I've decided to swap on a 280ZX 5-speed. A couple of questions, though:

 

1. Someone mentioned making sure to pull the speedo cable, and I was wondering if this is still applicable since I already have a 5-speed rear end (for purposes of speedometer accuracy) or if it is still just as relevant for that accuracy irregardless of the rear end I am using.

 

2. Someone brought up two connections present for the 4-speed manual for sensors, has anyone figured out how the single sensor on 280ZX transmissions relates so it can be hooked up properly? I'd hate to have the transmission installed and have the reverse lights come on in neutral, or not at all. :lol:

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  • 2 weeks later...

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