LocostUSA.com

Hey Newt..

The lessons learned from my T5 experiment were these: It will 'technically' work, and on some level it's worth the effort.. In my case the input shaft was slightly bent which gave me an intolerable vibration, but other than that, it was a sound design.. It was initially really nice to have an integrated reverse and .73 overdrive It did end up proving to be a bit of a redundancy however with all of those gears (6 bike gears + 5 T5 gears) from which to choose.. I found the VFR motor wants to be up past 5K at least to make any power, and the T5 gear spread was such that eventually I left the T5 alone, and did all of my shifting through the close-ratio VFR tranny (truth be told the VFR box was simply more fun to shift/drive.. using the T5 always felt slow/lazy).. It was at that point that I ditched the T5.. Pulling it removed my self-inflicted vibration issue, and it also removed 70lbs from the car (it was also at this point that I the car 100% needed a Guibo, so I was up for a redesign anyway) .. I came to rationalize that I didn't really 'need' reverse (you don't on a BEC, it's just nice to have)- and I never looked back..

I can't remember all of the details, but I think at that time I was still running a Miata 4.1(?) diff, and it was way, way off for highway use.. In the end, with the VFR / 7.5 diff / and 20" tires, I settled on a 2.73 ring and pinion.. It seems most BEC guys end up around 3.0/3.1 at the diff, depending on tire size and intended use for the car..

That T5 will work as you're planning, it's just a matter of what you want/expect from it..

--ccrunner

Yes, rip is the right word!

What application flange will you be using for the output? Any issue with having the hardened output shaft resplined or can you do that in-house too?

EDIT, I see you said 5th was going to be the output flange so no need to machine other than cut the end off of the output shaft. Looks like the shifter will be interesting.

Beautiful TIG welding

Nice. It looks like you brought the output shank up to the slip yoke od so you can use the standard output shaft seal. A nice compact 4 spd with reverse!

This is the way I should have done mine, but I don't have the knowledge base, or skill set, or machining ability... at very least this shows me that I need to get a lathe and to spend the time learning to use it

I know your build log is a bit behind real time, but I wonder if there's any gain for you to chop 7-8" off of that T5 (or is it now a T2? ) input shaft? A minimal weight loss, but maybe more importantly, it could help you lose a degree or two on your rear driveshaft angle..

--ccrunner

For the shifter...

Aren't there some variations of the T5 that have the shifter up on the tranny main cover? (the part you left intact).. I think it was on the Chevy S10 version??? Not sure if that's true, and I don't mean to send you down a rabbit hole, but I thought that shifter could be had in a more forward position than where you had to cut yours off of the tail..

--ccrunner

Impressive Newt! Are you going clutchless and torque tube versus a typical driveshaft?

CC, the s10 shifter base would require the output shaft flange to be 3-4 inches further out. With this arrangement, the shifter can "float" without being a factor in the position of the output flange. My spit has the s10 T5. The tailhousing extends another 11 inches or so past the shifter base.