BryanDowns

iTrader: (2)

Is there a source for something taller than 4.10 for my TII diff? Perhaps a 3.7X or 3.5X or something?

Thanks!

1987RX7guy

iTrader: (3)

Only place I could think of is Japan in their Auto FC's.

George84

Why would you want a taller rear end gear? Are you trying to make your car slower?

RoadRaceJosh

I have a feeling he's doing an engine swap and doesn't want to spend the money for an overdrive trans. Imagine not having 5th gear in your FC. Then imagine having an engine with a red-line 2500 RPM lower and you see how you can run out of RPM well before you run out of horsepower or even the 1/4 mile.

So are there any sources for FC turbo ring and pinions? I was told there is someone in Florida that makes FC gears, but I've been unable to confirm that.

Mindspin311

I wish I had a longer 5th gear, lower cruising RPM

C. Ludwig

iTrader: (27)

He's making close to 400whp in a purpose built Miata drag car that uses a TII diff. Why not just answer the question and not be a smart ***?

Bryan, us NA guys use the early short pinion gear with a section grafted in to make the pinion gear the proper length to fit the long snout case. Not completely sure but you might be able to do the same thing with an FD auto 3.90 gear. ISC Racing offers the service for $300. iscracing.net ISC claims they've never had one break. Every quick ITS FC runs a 5.12 or 4.88 built in this manner. It ain't drag launching but throwing 200 or so shifts at the pinion gear per race tests it fairly well.

Did the JDM TII autos come with a taller gear?

BryanDowns

iTrader: (2)

Thanks chris. Guys, I didnt mention it wasnt actually in an RX7 because I didnt want the thread to turn into questions about my car instead of about the diff ratio. I am in the middle of 4th gear in the 1/8 in my car currently. I am going to a 1/4 soon, and I fully expect to be in the middle of 5th gear with the current setup.

Given that I just bought a direct port nitrous setup, I may even be at the top of, or run out of 5th gear. The TII diff has held perfectly for me thus far, and ease of installation into my car was a big plus as well. It also keeps my car "all mazda" which is really cool

However, bumping the rev limiter in 5th would kind of rain on my parade to say the least....

cafcwest

I'm thinking FD auto rings *should* work.

Also, the 929 has the same 8.5 inch rear. They have a 3.73 final. I've got a complete diff chilling in my storage shed, awaiting a day I have a chance to dissassemble and test. I've heard mixed things about this.

BklynRX7

This may be the complete opposite of what your lookign for but just incase I figured Id post it.

http://www.rx7s.com/tandrracing/products/products.htm

The last item on the page, they say they do ti as a service but you may be able to buy parts from them if the fd gears fit.

Oni-kyan

I run a 3.90 from an auto rx7 ya I lost bottom end but gained top end so its not to bad take the ring and pinion and mount it to your diff.

BryanDowns

iTrader: (2)

929 of what year? Has anyone verified this? 3.73's are really in the ballpark of what I'd like to have. 3.9's are better than 4.10, but 3.73 I think would be PERFECT.