quote Originally posted by crazyd: Have u considered reading the whole thread before you post to it? My 282 is solid-mounted with axle support bearings. Lots of axles broke, but the trans hasn't.

I never really saw him talk about it or consider it in the thread just alot of other people talking about it. I would like to see HIM try one or the other to see how it runs with the engine, and how long it lasts with his over 400 hp dohc and how he drives it.

You might consider using the jack shaft version of the berretta tranny. By adding the jack shaft 2 things will happen. You will end up with two axles the same length, and eliminate the torque steer by axle wrap. And most important, stabilize the all too weak speedo side of the differential by plugging in the jack axle that has more support and does not have radial deflection forces applied to it.


Ask yourself this question, how many Hi-Po front drive cars these days have long and short axles?

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yellow 88 GT, not stock
white 88 notchie, 4 banger

Excellent idea, completely agree on the jackshaft. How is the jackshaft version differentiated from the regular version? Years, models, engines, etc...

I think they are 90-91 lumina, sunbirds and berettas that use these. There are several posts about them in the forum.

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yellow 88 GT, not stock
white 88 notchie, 4 banger

the get 5spd is pure junk when expossed to high torque I have broken 4 in my 90 Z24 with 3.1 v6 launched at 4000 rpm the diff poped clean out of the case and thats with the support shaft
and short axle first one when with only 600 klm on it gm replaced it second whent at 1400 klm gm replaced it also stoped racing the car no more brocken till i raced it again broke 2 more
then sold the car gave up on the trannies

quote Originally posted by Kemp3: Look at the gear ratio's of the F40 vs the NSX tranny . I am currently doing a engine swap and now stuck at my drivetrain decision . If can I muster up the extra 1g I will go with the NSX, GM front wheel drive manual tranny's have the worst gearing as far as I am concerned . There are a few places who sell the J4A4 ( 5speed ) rebuilt for racing applications, here is one http://daliracing.com/v666-5/welcome.cfm . I am interested to see the end result of this topic -Jared

the NSX has good gear-to-gear transitions, very nicely spaced, but the 1st gear is by no means great in it, since the final drive in it is 4.06:1. the overall 1st gear is still 12.5:1 or thereabouts, which is on par with the 12.6:1 of the 5 speed getrag.. not a big improvement... it is still a tranny for a high-revving 7K+ rpm engine...

one thing i DID notice about the NSX tranny, was the fact that it has a boss for mounting a starter on it, which would make it a decent candidate for an LS4 manual tranny swap however, notching out the frame rail scares me

quote Originally posted by ccfiero350: You might consider using the jack shaft version of the berretta tranny. By adding the jack shaft 2 things will happen. You will end up with two axles the same length, and eliminate the torque steer by axle wrap. And most important, stabilize the all too weak speedo side of the differential by plugging in the jack axle that has more support and does not have radial deflection forces applied to it. Ask yourself this question, how many Hi-Po front drive cars these days have long and short axles?

1. Fieros don't torque steer. Torque steer from different length axles in a FWD cars stems from different restoring forces on the CV joints at different angles. Axle wind-up is a non-issue.

2. "Radial forces" on the right side diff bearing boss are a non-issue. What causes that boss to fail is axial loading from the final drive mesh helix angle. The vast majority of radial loading is taken by the LEFT diff bearing boss. That's why that side of the case has so many reinforcing ribs on it.