Pro-shifted Transmission MOD (A Cheap Legal Solution for RX7 Drag Racers)
 

Apparently, Crispeed is already using this.


This is how you would turn your stock 5 speed Mazda transmission into a pro-shifted transmission

You take the blocking rings out or grind the teeth off them. You then grind every other tooth off the dog gear and off the inside of the slider.

This would allow your stock 5 speed transmission to shift like a pro-shifted G-Force, Liberty etc. etc. etc.
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Let me know if there is anything I am leaving out.

Damm.
That shit been bothering you ever since I mentioned it huh? :)
You can also send some parts out to Liberity and have them do it for you.

Yeah it has :crying: , I emailed Liberty earlier about that they would charge for that modification. Did you do your transmission by yourself?

Can you give better instructions on how to do this? :cool:

That pretty much sums it up. Once you get that done then you can install a 'Long' shifter to help eliminate any missed shifts.

how long would you reccomend?

Did you do your mod yourself or did you send yours off?

I'd rather do it myself :101384_l:

A 'Long' shifter is a vertigate shifter that's used on the 'G-Force' clutchless transmissions.

I thought you meant a pickup shifter :crying:

I looked at those G-Force long shifters. It looks like there is noway that those would work on the stock transmission. It seems a regular shifter would work. How about some pictures of yours? :)

You need to fab. It's not bolt on. Simple explaination would be to drill three holes in the case in the area around where the rods/forks are. Remove the forks and extend the rods outwards to meet with shifter rods then you simply fab a mount on the tail shaft to mount the shifter.
Plus I stopped using the stock box a long time ago. In the end you're still going to break gears once you start making some serious torque. The stock case has a lot to do with that also. It flexes too much.
The shifter is not legal for the 'street class' at NHRA but it is for everything else.
The dog gear setup is so old school that I have not done it in like 10yrs. :)
The new method is to machined the factory dogs off and weld on a face plate type engagement like Liberity does.
Lupe onced my last stock tranny broked on the dyno I switched over to a Richmond(Dougnash) 4+1 tranny.

This sounds like a great option for Schecter and whoever else plans on running the NHRA Sport RWD class. I emailed Liberty about the price of doing the pro-shifted mod and faceplate mod. Actually, found out that they only charge like $200 total if you send them your parts.

And Paul at Liberty said it would be $4k to change it to a total dog box. :) BUT the problem is the main shaft will still crack. Thats the problem Ari has been fighting with.

Hey Crispeed. I don't know if you are interested but i got in touch with a guy that does all kinds of mods to the DN 4+1. He has a large selection of new and used gears and he also does face engagement conversions. He even says that they have a conversion to run a G-force gear set in a DN case.

Does your DN have the torque tube? And what ratios are you running?

Allen

Yep
I know exactly what he's dealing with. I give up on the stock tranny a long time ago. The cost of making the stock tranny work is not worth it. Plus in the end it still has a limit. You can have a main shaft made out of 300m but the cost is going to be very high. The next thing is going to be the gears which are available allready in straight cut design. At least the straight cut design helps with the gears trying to walk away from each other which happens to be the main cause of gear breakage.
I've seen the entire cluster gear section shoot out the bottom of the tranny behind a 600rwhp + monster. It cracked the case in two and that was on a fourth gear shift too.:)

Oddly, I was *just* talking with my boss's dad about this. He used to do this for his and his customers' trannies in the 60's/70's.

This is what got me. He has no rotary experience, but he advised me to NOT take any splines off, that when they did this they had a tendency to shear the remaining ones clean off if the shifts weren't done just right and/or for big power cars, BUT they would still shift just fine with *ALL* of the teeth intact!

I have enough junk trannies that I plan on doing this, just to try it! He also said you could either take all of the teeth off of the synchros, or if the detents in the shift rails were strong enough, just remove the synchros and the keeper finger things (inside the slider) altogether. Only reason to keep the synchros is to keep the fingers in place, the fingers act as additional detents as well as keeping the synchros in sync with the sliders. Without the fingers, things can move around a bit.

*NOTE* - I'm playing with the junk smoothcase transmissions, NOT the Turbo/FD units. Minor strength difference :D And his idea of "big power" is somewhat higher than a rotary, for much heavier chassis...

I sold the tranny to a friend. Mines didn't have the torque tube. I know of the mods that can be done. I did most of mines in house. I even re-bushed the crowns in house.:)
The only thing I bought from Paul at Liberity would be new sliders. You have to learn to repair those trannys the hard way because parts use to be very hard to come by plus a couple of full throttle missed shifts behind a 700rwhp motor at 10k rpm would normally take out the sliders and damage the crowns.

This guy works out of a shop at his house and he told me that if i could break it he could fix it.:) How many times did you lunch your trans when it was in your car?
https://img141.imageshack.us/img141/...10771cn.th.jpg
http://img137.imageshack.us/img137/4...10760zz.th.jpg

Probably about a 100 times!:) Most of them never under 9500rpm or 20psi!")
With the wrong clutch setup I've seen all-motor cars snaped the input shaft or gears of G-Force. The torque tube does take a lot of the shock out though.

Anyone have Libertys phone number or website? I need to look at a transmission option that will keep me legal for SRWD.

I should be getting my T56 back from Liberty's next week with the face plate modifications.

Andrew

What are the rules for SRWD? Can you run a transmission that is not the same make as the car or engine?

I just got my Liberty T56 for my LS1 FC. Its incredible!

Andrew

You Must use a Mazda Trans
thats it..Does not have to be a RX-7 one

Mark's 240sx uses a early 300ZX 5 speed trans and is Legal for NHRA sport class
easy street WRX uses a subaru legacy hybrid race automatic

is there a stronger mazda 5 or 4 speed out there?

Too bad you have to use a Mazda trans. Here is an incar video of the Liberty T56 in action in my FC. The first part of the video was to show the noise driving around town using the clutch. The two power runs were clutchless with slightly lifting on the throttle between shifts.

http://video.ls1tech.com/video/65c44...0673dcf0dc.htm

Andrew

anyone know if this will work w/ a ford t5 as well? i dont care if it breaks once a month lol. rebuild kits r 250 bucks so its not a big deal. any helps apprieciated. thanks =D

Pictures of Modified Mazda Trans w/Long Shifter
 

Crispeed, Do you have any pictures of your old setup that you mentioned using a Long Shifter with a Stock Mazda Trans? Just curious how you set it up and where you made the 3 Holes in the Tranny Case. I have a All Motor car so I am not too worried about making too much Torque to grenade a Turbo II or FD style transmission.

Any help would be greatly appreciated.
Albert

old but good thread