Thread: Which B15 Gear box

I was wondering which gear box you guys think would be best of the the two.
The regular 5 speed b15 gear box or the spec v 6 speed gear box. This is for a real high hp N/A sentra on slicks. I know with the 6 speed gear box you have stronger gear box and axles, however what about the gearing? I know maxworx is working on a 6 speed conversion kit so which would be best? Any input would be great thanks guys.

5 speed u can drop in now. The 6spd u will need more parts, I don't know if there making an adapter plate or u still have to buy the 20V bellhousing and bolt that up to the spec V trans.

I know the 6 speed is going to a lot more work i was just wondering gear ratio wise. I hope they make an adapter but im just putting out the option in general.

depends on the year 6 speed should have a close ratio that the B15 5 speed.

Dude, you're going N/A. You could probably get away with a B13/B14 tranny. It's not till above 300-350HP that you have to worry about those trannies cracking. And if you have the case welded, you'll be just fine.

If you're not ok with sticking to the original stuff, just get the 5-speed B15, swap it right in, and be done with it.

I see a couple people on here with about 220whp breaking stuff. Im planning to go as high as i can with my n/a and im not trying to break something all the time. I would just like to be safe then sorry. Plus if you have a high horsepower N/A car your going to need bigger slicks for the power and i dont know how our gear boxes with really do with that. Thank you for your input though.

I've heard of broken axles, I broke one myself without slicks. I've never heard of someone cracking a case with only 220 WHP...

Cracking the case really has nothing to do with whp or tq. It's wheel hop that makes it happen.

I've always heard that the case will crack in 3rd gear from power in excess of 300whp

No 3rd gear itself sheers with abuse with b13/p10 and b14/p11 (pre 00') trannies. The case cracks from wheel hop.