Still trying to find a stupid 5 speed. I've been in contact with some JDM engine/trans importer in New Jersey, he says he has them in stock, sent me an invoice on Paypal but when I asked to see pictures of the transmission he just keeps stalling so I haven't sent payment.

 

Sounds like your typical JDM importer. Hope you find something worth your time and money man.

 

sorry, my bad on the original post, it was recently sold

This one is a bit steep

http://www.ebay.com/itm/JDM-04-08-MA...04479c&vxp=mtr


.

 

Do you have more than one at that price

 

I'll say. Paid 500 for mine..and they're plenty rare here. And wtf!! They cut off the tailshaft!! Idiots

 

Take a look at Ebay UK, type in RX8 5 speed gearbox, there are many ranging from 99GBP.

 

I wish I could find one for $300.

That bozo has had that thing listed for like a month at just under $1000, looks like he relisted it as an auction. It used to be a "Buy It Now" button and a "Submit Offer" button. I offered $350, then $450, then $600 and he declined all of them. Shipping for him would be cheap too, only one state away and I have a business address with a forklift it can go to if necessary.

 

It seems that the word has gone out that they are a bit rare and hard to find.


Maybe look to see if you can get the bellhousing and tailshaft from UK and add them to a FD tranny

 

Well, turns out the JDM importer I was talking to had sent the pictures like a week after I requested them, but didn't really mention it in the email that they were attached so I missed them. So, good to go. Trans looks clean and supposedly has about 40,000 miles on it but who knows. The pictures showed it still attached to a low power 4 port, and the engine had an R Magic oil filter on it which is common in Japan, so it's highly likely that it's the JDM version that I would prefer and not the EUDM version.

Yay.

Also I picked up a wiring board from Leash Electronics that I'll be using to wire the car from scratch.

Mad JDM tyte busted up shift **** because pictures are fun...

 

So in this post I wanted to explain the differences between gear ratio differences between the JDM and the EUDM 5 speed manuals and why I prefer the JDM version for my application.

The JDM RX8 5 speed gear set is identical to the JDM RX-7 FD ratios. The EUDM gear set has a 3rd gear ratio that I don't really see used in any other RX or Miata gear boxes, but the 5th gear ratio is identical to a Turbo II.

Gear Ratios:

Gear -- JDM -- EUDM
1 ----- 3.483 -- 3.483
2 ----- 2.015 -- 2.015
3 ----- 1.391 -- 1.484
4 ----- 1.000 -- 1.000
5 ----- 0.806 -- 0.762
R ----- 3.288 -- 3.288

Now the reason I like the JDM version better is because the RPM drop from 3rd to 4th isn't as big and disproportionate as the EUDM box, and the 4th to 5th gear RPM drop is almost 400RPM less as well.

I will still be able to get up to about 165MPH at the rev limiter with the stock diff and 275/30R18 tires. I might be able to get close to that on only a handful of tracks and is dependent on a lot of things but I don't think I'll ever be able to top out the car on a road course. But who knows.

Also, playing around with the MFactory Ratio Calculator is always fun. This will help you see the differences in RPM drop when you shift gears.

 

The good thing is they are almost impossible to break with 150HP

I'm sure the ones I have are JDM as well....



Posted From RX8Club.com Android App

 

you sure about 5th ? I thought the FD had .719 5th gear?

Posted From RX8Club.com Android App

 

Yep. In Japan the FD has a .806 fifth gear, and the USDM FD has a .719.

The brochure for the JDM RX8 lists the fifth gear as .806 for the five speed manual.

 

That's a good thing......the best option for a track car for sure..it might actually make 5th gear usable

I sure hope this option works out like I'm hoping....I really don't want to do a T56 or T5 swap....I hate the way both of those transmissions shift

 

Lol I don't know why you're so hung up on "the way they shift". You have a racecar no? I would assume you would get a dog engagement gear set and a nice shifter. It won't shift anywhere near the same as a normal synchromesh transmission, you'll be slamming gears with a dog box anyways.

My end game is to get a GForce GF5r dog box with straight cut gears into the car which is loosely based on a T5 design. This 5 speed is just something to hold me over until then.

 

I have a FD Dog box in another car...It shifts great racing...but driving it around slowly at all is a PIA

The T56 dog box is unnecessary for the power levels we are running. The gears are wide and heavy and the tranny shifts like that. Same with the T5 Variant that you are talking about.

I am going to run a 5 speed stock for a bit...if it hold up like I hope..I m going to build one with REM'd gears and tapered roller bearings and that should work well. I just want to run it stock first before I spend a grand or so upgrading it before I know it will work

 

Have you guys considered a straight cut T56 with sequential shift .

 

are you sure that a 275/30-18 tire size isn't a typo?

 

No. Sequential isn't allowed in the class I want to compete in at Global Time Attack, and the T56 is heavy.

Sorry you're right I was thinking about 285/30r18. 275 is most common in a 35 profile on 18's but you get the idea. Only changes by 1MPH.

 

Arca, Maybe I missed it, But what Engine Mount/oil pan setup did you go with?

 

Going to be using the stock oil pan with an oil pan brace and stud kit for now. Making a billet aluminum dry sump pan is on the to do list after it is up and running. Also using the RX8Performance mount.

 

This a fun thread to read man. Really cool to see your progress as a driver! If you were to participate on a Nasa TT event, after you complete your swap, what class would it be? I have the intention of doing HDPE events with the goal of participating at TT events later. The whole TTU~3/TTB~F classing can get pretty confusing.

 

Thanks man.

I'm planning on doing TT1 with it. It would normally be a TTU (unlimited) car but with electronic boost control I can dial it back for TT1 or TT2 as well. Maybe even TT3 but I might make too much power on wastegate spring to fit into TT3.

The classing isn't too bad it just takes some time to thoroughly read them. If you ever need any help with classing your car you can just PM me.

 

Thanks man. I'll take my time and try to understand it a little better. One of my main questions is about the cage. Do I need a 6 point cage for TT123? I have built a cage before for my S14 drift car and wouldn't mind building another one. But if I can save the weight and cost of materials to spend else where, I would.

 

It's not required but at those speeds I would at least have a 4 point rollbar, seats, harnesses, and a head/neck restraint like a Necksgen or HANS.

Did you do an engine swap as well to get up into those classes?