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Gearbox Mods For Racing

Noddy

By Noddy,
in Motorsport Discussion & Builds

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Dale FZ1 Veteran

Dale FZ1

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Posted

I'd reckon 6th gear in the Tremec would be pretty much redundant for track use. Ratio selection/spread for 1-2-3 looks to be an improvement. Torque-load capacity obviously is a plus, so the things that I'd like to know is

1. how it handles quick-ish changes at high engine speeds

2. whether this box has its own selection of little components that fail like those little spring clips in the R33 box

3. how difficult/expensive is it to give a Tremec a freshen up if bits do get tired

4. how difficult/expensive is it to engineer a Tremec into a R chassis

Not being negative, and I appreciate that Stuart is having a go at building a better package within a sane budget. Mostly I want to know if it's the sort of upgrade I would want to do. :)

Noddy Proficient

Noddy

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Posted (edited)

Hey noddy, the issue u were having with the rb25 box failing, was it typically going up the gears ie from 3rd into 4th or going down the gears from 4th to 3rd when it would fail? Thanks

What does the initial damage? Probably a miss shift up to third. There is an awesome technical little track in Stanhope that is all 2nd and third gear. Twice over the last 10 years I've come away snicketty from there where I know I rushed the up shift and forced it in. At morgan park and lakeside on a down change to 4th a similar problem where I didn't get a big enough blip in and rushed the synchros.

Putting the third brass guide at the top definitely helped. We replaced the side ones too, they are pretty wrecked in most of the boxes we see. post-15176-14237442983836_thumb.jpg

Why go to a T56? Well, my gearbox guy did all the development work for MallWood and has had a lot of experience with them. They normally have a number of Teflon parts that he has replaced with various metals. He has a few tricks up his sleeve that have gone into this box.

The other major factor was that I was so over the 25 box. A bit over 12 months ago I sourced a late model (2000) 34 box and gave it all the things we have learnt over the last 8 or so years. 1st meeting of 2014, ttt weekend at morgan park, Saturday was just cruising through the gears beading it in. Sunday, 1st run 2nd lap up to 4th nice and easy.... crunch, and got worse every lap. The dogs on 4th were chewed to hell. Went hunting for parts and ended up with brand new 4th gear and selector hub.

Shared the car at a mate who has been racing since the late 60's. I was racing he was doing a super sprint. We bedded the box in Friday practice and it felt really good. After the 2nd round on Sunday... bag of dicks. Some how bruce killed it.

Went hunting and found a nice 32 GTR box to use, gave it all the tricks and raced at the lakeside classic. No practice so panzied through qually to bed it in. The race meeting went well, no issues, but I just didn't like the feel of it. Didn't touch the car again until the end of the year for a sponsor ride day at QR. It was fine.

I spent the year racing my TRD Japan built AE86 and building a new motor for the 33. The new 30-26 should push a bucket load of torque. 9.2:1 comp, 1 mm oversize valves 88mm pistions 256/272 big lift cams with trust manifold and a pair of TD05's. What is going to stand up to the grunt, handle the race track and fit the budget?

Edited by Noddy

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