Wesley Posted April 10, 2012 Share Posted April 10, 2012 Hi there. I am currently doing a rebuild on my 1978 Datsun 280z. I am most likely going to be putting down roughly 260HP at the high end to the fly wheel so nothing too extreme. ( But it will be more like 225HP) Here is the deal. I have the stock 5 speed and R200 that came with the car. I am dropping the transmission and will be rebuilding it no matter what. My question is since I can pick up a T5 or any kind of transmission that came on the L series for no real cost. Should I bother swapping transmissions?(Since I will be rebuilding the transmission that goes into the car regardless) What kind of modifications would I be looking at?(I assume there is a post about how to do this already I just don't know what transmission yet) Or should I just rebuild my transmission?(I feel like 3rd gear drops off but this is also with a stock setup i.e. 110HP maybe) Thank You. Quote Link to comment Share on other sites More sharing options...
Josh280z Posted April 10, 2012 Share Posted April 10, 2012 Look HERE for more information regarding this. I had similar questions to yours, hopefully this helps. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted April 10, 2012 Share Posted April 10, 2012 The stock 280z 5 speed trans has a big ratio jump between 2nd & 3rd gear.And 5th is too close to 4th.The t5 has some wierd ratios.I have a built turbo engine but i used to use my car on road course track days.I use a 83 280zx na trans.nice ratio spread and best 5th for freeway running.run this trans with a 3.7 or 3.9 rear Quote Link to comment Share on other sites More sharing options...
tamo3 Posted April 10, 2012 Share Posted April 10, 2012 Changing 71B to T5, it will increase about 70lbs. Just FYI Quote Link to comment Share on other sites More sharing options...
luseboy Posted April 11, 2012 Share Posted April 11, 2012 There's always the 240sx s13 trans swap. I'm gonna do it some day, but it does require some custom work. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted April 11, 2012 Share Posted April 11, 2012 I wrote a tutorial on the SR transmission swap a few years ago. Unfortunately doesn't have any pictures. Still might be of some use: http://forums.hybridz.org/index.php/topic/40643-tutorial-sr-gearbox-onto-l-series-engine/page__p__331608__fromsearch__1#entry331608 Dave Quote Link to comment Share on other sites More sharing options...
Wesley Posted April 11, 2012 Author Share Posted April 11, 2012 The stock 280z 5 speed trans has a big ratio jump between 2nd & 3rd gear.And 5th is too close to 4th.The t5 has some wierd ratios.I have a built turbo engine but i used to use my car on road course track days.I use a 83 280zx na trans.nice ratio spread and best 5th for freeway running.run this trans with a 3.7 or 3.9 rear You answered my question thank you! How would I go about identifying the 280zx transmission? Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 11, 2012 Share Posted April 11, 2012 Changing 71B to T5, it will increase about 70lbs. Just FYI The T5 does not weigh 70 lbs more than the NA tranny. I have both in my basement but am on the road so can't weigh them. I'd guess the difference is more around 10-20 lbs, but that's just going from memory. I've been running an 81-83 NA tranny with 4.11 and loved it when I had a NA L28 with moderate cam. But it turns 3100 rpm at 75 rpm which is a bit busy so a 3.9 might be a better choice for the street. 3.7 is probably good with the NA cam that runs out of steam by 5500 rpm. Experiment with this to see how changing transmission, diff, and redline all affect your speed in each gear. After a year of running a turbo the tranny is starting to fail so I'll be swapping to a T5 and 3.54 or 3.7. Quote Link to comment Share on other sites More sharing options...
Wesley Posted April 11, 2012 Author Share Posted April 11, 2012 The T5 does not weigh 70 lbs more than the NA tranny. I have both in my basement but am on the road so can't weigh them. I'd guess the difference is more around 10-20 lbs, but that's just going from memory. I've been running an 81-83 NA tranny with 4.11 and loved it when I had a NA L28 with moderate cam. But it turns 3100 rpm at 75 rpm which is a bit busy so a 3.9 might be a better choice for the street. 3.7 is probably good with the NA cam that runs out of steam by 5500 rpm. Experiment with this to see how changing transmission, diff, and redline all affect your speed in each gear. After a year of running a turbo the tranny is starting to fail so I'll be swapping to a T5 and 3.54 or 3.7. Very handy Calculator! Thank You. Quote Link to comment Share on other sites More sharing options...
duragg Posted April 12, 2012 Share Posted April 12, 2012 The ratios on the 83 280zx tranny are perfect (or close to it). 1000x better than the early 5 speed. I have a 4.38 with little tires and the 83 5 speed. Its a little busy up till about 45mph then all done... Quote Link to comment Share on other sites More sharing options...
Zmanco Posted April 12, 2012 Share Posted April 12, 2012 Just checked with a bathroom scale and the T5 weighs ~20 lbs more than an 81-83 ZX 5 speed. Quote Link to comment Share on other sites More sharing options...
zentech Posted April 22, 2012 Share Posted April 22, 2012 Just checked with a bathroom scale and the T5 weighs ~20 lbs more than an 81-83 ZX 5 speed. You're correct i had quite a few of those back in the early 90's that i shipped to individuals all over and bought them for racing application.The T-5 trans weighs more than the non turbo 5/speeds. Quote Link to comment Share on other sites More sharing options...
Kali Posted April 22, 2012 Share Posted April 22, 2012 Got nothin but time here at work fig id add my two cents S13 Gear Ratio 1st- 3.321 2nd- 1.902 3rd- 1.308 4th- 1.000 5th- 0.759 Z32 Gear Ratio 1st- 3.214 2nd- 1.925 3rd- 1.302 4th- 1.000 5th- 0.752 T5 Gear Ratio 1st- 3.50 2nd- 2.14 3rd- 1.38 4th- 1.00 5th- 0.78 references http://en.wikibooks.org/wiki/Nissan_240SX_Performance_Modification/Transmission http://www.zshop.net.au/Z32tech.htm http://www.zhome.com/ZCMnL/tech/GearRatios.html Quote Link to comment Share on other sites More sharing options...
Nigel Posted April 22, 2012 Share Posted April 22, 2012 Here's just about everything you'd ever want to know about the S13/S14 swap: My lihttp://www.motortopia.com/cars/1973-datsun-240z-11118/car-pictures/240sx-transmission-swap-14041nk Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
tamo3 Posted April 25, 2012 Share Posted April 25, 2012 Sorry for the wrong weight information. T5 itself weight 75lbs not more than 71B. http://www.datsunzgarage.com/borg/ Reference for how to identify 71B and 280z/zx 71C http://www.the510realm.com/viewtopic.php?f=30&t=12276 Quote Link to comment Share on other sites More sharing options...
rejracer Posted April 26, 2012 Share Posted April 26, 2012 Each trans has it's advantages. With a T5 you can go with WC box or there are aftermarket upgrades. If you stay with a 71B it opens up the option of upgrading it with the 300zx or 240sx internals later. T5's are cheaper to rebuild and have the later option of a G-force upgrade. 71B, 71C (300zx), and 71H(240sx) transmissions are cheap and plentiful in the junkyards, and have a smoother shift feel to me. My opinion: Out of the box the 71B/C/H transmissions are a better choice. Upgraded the nod goes to the T5. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.