logan1 Posted December 23, 2010 Share Posted December 23, 2010 (edited) Hi guys, I am currently in the process of swaping a BW T5 and a R200 into my 240z. Currently my car is running the stock L24 motor with a racing cam but i would like to replace it soon with a L28et with approx 300 whp. The car is going to be a daily driver for the most. In your opinion will the 3.70 be a better ration for the BW T5 or will the 3.90 be better. I am afraid that if i swap in the 3.90 my gears would run out too quick. Keep in mind that i will be swapping in a Turbo L28et motor soon. Edited December 23, 2010 by logan1 Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted December 24, 2010 Share Posted December 24, 2010 The 1st gear ratio in the T5 is ~3.06 - just about like the 1st gear in a 4L60/E or TH700R4, and many lament that short/steep gearing. Unless you want to run a much hotter/higher rpm cam in the turbo than stock, you would probably be better off with a 3.54 rear gear - like stock on the turbos. Turbos like something to work against to build boost. A 3.90 would be totally wrong for a turbo with the size wheels we are normally able to run. Now if you tub the rear and make room for taller tires... Quote Link to comment Share on other sites More sharing options...
280zex Posted January 3, 2011 Share Posted January 3, 2011 Yup just what Brad-Man said. I have the T5 and 3.90 rear with a turbo setup. I have to shift so damn fast to keep the turbo working is a pita.. 60 mph is 3k rpm in 5th with 225/50/15's. I shoulda kept the 3.54 but I sold it... Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted January 3, 2011 Share Posted January 3, 2011 (edited) Assuming this is a Nissan BW T5 the first gear is 3.50, not 3.06. With the 3.54 r&p that translates to 12.39. With a 3.7 it is 12.95 and with the 3.9 it is 13.65! You'll be shifting into 2nd before you get through the intersection. I'm building a Nissan BW WC T5 using a 2.95 first gear and a 3.90 r&p. That's 11.505. That's a difference of .885 from the 3.54 which is a lot (1.445 with the 3.7 and 2.145 with the 3.9!). I did this by mounting the Nissan BW T5 bellhousing, top cover and tailhousing to a WC case. It will require a 240mm flywheel and 10 spline clutch rag or custom 10 spline clutch rag if using the 225mm flywheel. You'll also need to relocate the speedo gear on the mainshaft. None of this is complicated though. Edited January 4, 2011 by ezzzzzzz Quote Link to comment Share on other sites More sharing options...
280zex Posted January 4, 2011 Share Posted January 4, 2011 Thats right ezzzzzzz I do have to shift just before a crosswalk in a inersection. Usualy I just take off in 2nd.. Quote Link to comment Share on other sites More sharing options...
240zip Posted January 4, 2011 Share Posted January 4, 2011 Is it possible to find alternate first gears for the Nissan BW T5? Does anyone have such a source? Quote Link to comment Share on other sites More sharing options...
ezzzzzzz Posted January 4, 2011 Share Posted January 4, 2011 (edited) Is it possible to find alternate first gears for the Nissan BW T5? Does anyone have such a source? This is a NWC T5. You would need to find a complete gearset (used or new) to get a different first gear ratio. Just swapping in another input shaft would not be viable as it would be horribly noisy as the countershaft is a solid assembly so you couldn't just swap out the matching fourth gear. If you choose to swap gearsets you will also need to have a custom pilot bushing made from oilite bronze (no big deal) because the OD is different. You'll need to use a Ford gearset so the input shaft length isn't an issue (7.18" vs 7.188") and probably move to a 240mm flywheel for the Ford clutch or have a custom clutch rag made (again not a big deal). Edited January 4, 2011 by ezzzzzzz Quote Link to comment Share on other sites More sharing options...
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