6 speed manual for L-series engine?

[kensval]

Does anyone know of a 6 speed tranny that will bolt up to an L-series engine?

[Blue]

I think a japanese variant of the 240sx has a 6 speed that will work but some mods are required.... machining Z bell housing and drive shaft shortening and cross member adjustment. Most just use a 240sx transmission for better shifting but the same mods are required to make it work.

[kensval]

I've already got the later 5-speed in my '76, which does help greatly on the highway. I'm just looking for options that will cause me the least amount of headaches should I decide to move up to a 6-speed. Sounds like there's no real easy way to do it. What about a 6-speed from a late model Z?

[Blue]

There are no bolt-in 6 speeds that I know of. Have you considered changing the differential to move you into either into quick launch or low cruise rpm?

[kensval]

Hadn't considered that as of yet. Maybe down the road. Went looking online last night to see if I could find anyone producing a new, conventional 6 spd manual with a separate bellhousing, but was mostly unsuccessful. Tremec and Richmond both make 6 speeds, but they're designed, and sized, for American V8 cars and trucks. Might have to do a lot of sheetmetal work to make one of them work in a Z car, and with the original L-series engine's limited power, they'd be overkill. What was the brand of the 4 and 5 speeds in the original Z cars? Did Nissan make their own, or were they outsourced?

[jmortensen]

There is at least one person who put a T56 behind an L6 in a turbo 510 no less. It's a lot of work and the T56 gets you a .5 overdrive 6th gear, so basically 6th is worthless unless you plan on driving 250 mph. I would suggest you stick with a 5 speed. The L motor doesn't usually have such a narrow power band that you need a 6, and it's not sufficiently torquey that you can idle up a steep grade like you can with a big V8.

[kensval]

I read somewhere that some later Z cars brought into the U.S. came with Borg-Warner T-5 trannys. I had one of those in a Mustang I used to have. Not a great transmission, at least not the earlier ones.

I'll probably stick with the 5 speed I already have. It's gotten me up to 140 MPH. That's fast enough. However, I'm already thinking of looking for another Z to stuff a V8 into and that one I won't really care about changing the sheetmetal on so if I have to make a new tranny tunnel, so be it.

Still, if I never asked, I might still be wondering if I could have had another gear...

[sblake01]

I read somewhere that some later Z cars brought into the U.S. came with Borg-Warner T-5 trannys....

The 280ZX Turbos had that trans.

[jmortensen]

Yep, 280ZXT. The later 280ZX NA 5 speed (80-83) has much better gear ratios for a NA car though. The earlier Z 5 speeds and the T5 have very wide ratios, not so good IMO.

[John Coffey]

Taylor Race Engineers can easily build a Quaife Sequential 6 speed that will bolt up to your L6. They built me a 5 speed sequential a few years ago.

[kensval]

I took a quick look at their website, which took me to the Quaife site. How much did you pay for your 5 speed? I saw £6595.00 for the 6 speed. I might be able to absorb $3000 or so for a tranny, but not $15,000. Cool idea, though. A sequential would be great for when I build my spare L28 into a turbo stroker.

[sblake01]

I think £6595.00 would actually be more in the range of somewhere between $10,000-$10,500 but it's still more than I'd want to ante up for a tranny. I could buy 3, maybe 4 Borg Warner T-56 6 speeds for that amount.

[kensval]

You're right on the approx. cost. I guess the pound isn't as strong as it used to be. Would the T-56 actually fit an S30 without (major) sheetmetal mods? It's been pointed out that a mostly stock L28 probably wouldn't have the torque for 6th gear, but perhaps with a turbo'd stroker it might be go. I've been trying to decide on whether to sell my spare L28 or to look for a diesel crank and build a much stronger engine than my warmed over original engine.

If I'm not careful I'll just end up looking for another chassis, build the stroker, buy the 6 speed, do two restorations concurrently, then have to sell both cars to pay for the divorce.

[sblake01]

I doubt that a T-56 would fit an L-motor without major mods. I've had the trans out of my GTO and, as I recall, it wouln't even be close. Starter location, size of belhousing, etc.

[jmortensen]

It fits the S30 with some persuasion from a BFH. The big problem is that it really doesn't give you ANY performance benefit, because the 6th is not moving 1-5 closer together. It's slightly closer ratio that a 280ZX 5 speed, but not a huge difference. I would expect that the extra 75 lbs (yep, it weighs 150 lbs) plus having to screw with a starter and crossmember and driveshaft to fit it would not be worth the hassle. It's your money, but I wouldn't do it. The reason the 510 guy did is because he was spraying nitrous on his turbo'd drag racer and blowing up the T5 trans.

[Blue]

Here is the one I was thinking of:


One for sale here: (Eastern Canada) Click

Transmission	1st	2nd	3rd	4th	5th	6th	Final
NISMO Reinforced Cross	2.9071	1.9888	1.5373	1.2179	1.0000	0.8624	-
Genuine 6-speed (FS6R92A)	3.6264	2.2000	1.5412	1.2132	1.0000	0.7674	3.6920
Genuine 5-speed (FS5W71C )	3.3214	1.9023	1.3084	1.0000	0.8378	-	4.0830

[sblake01]

I called the T56 a Borg Warner in my post above (out of habit) but its actually a Tremec. That Silvia trans looks like to be a Borg Warner, however.

[jmortensen]

That NISMO one has good ratios. It wouldn't be worthwhile to me to adapt it in, but different strokes and all that.

[John Coffey]

$7,500 for my sequential 5 speed and that included straight cut gears, the dog ring option, custom ratios, the gear indicator display I ran where the speedo was, an "A" box bellhousing, and the custom machined adapter plate.