hsitko

iTrader: (1)

What is the best oem transmission for these cars. For all reasons. Gear ratios, updates to design, mileage? Is there a particular ring gear that is most apropiately matched to a specific transmission? And what do they typically cost, and lastly where can i get them. I am currently in a rebuild and want everything to be nice and fresh when i drive this car again. My trans ground 2nd and 5th. So let me know what you think! Thanks

--Hank

dgeesaman

iTrader: (7)

The final ratio all depends on whether you want fuel economy or better punch. It really doesn't matter.

The 'best' tranny is one with new synchros and completely unworn hard parts. The difficulty with rebuilding a tranny that was grinding is the clutch sliders and gear teeth are rounded off and replacing the synchros doesn't really solve the problem at all. In a rebuild, unless your rebuilder has affordable replacement hard parts on hand, you will either end up with a huge bill (gears and clutch hub assemblies run over $200/ea) or you might not get the clean shifting you hoped for.

My personal opinion is the best way to fix a grinding/clunking tranny is to start witht he best possible hard parts. "JDM" imported trannys can be very good, if you can buy one with undamaged hard parts. Plus some JDM trannys come with a different 5th gear ratio which some people feel is advantageous.

Dave

hsitko

iTrader: (1)

So, what are the different ratios for the Ring gear? Also what are the differences in ratio for the jdm trans compared to the us one? Is there anything better about say the later model transmissions in japan? Do they use any different parts? From say something like a 99 or newer? Thanks!

--Hank

Narfle

iTrader: (16)

The JDM trans unit has a more apropriate overdrive ratio. The T2 differential uses a clutch typre limited slip as opposed to a viscous unit found in the FD unit(if im not mistaken). The T2 diff can handle more power But iirc the FD unit was heralded as a more street friendly unit with more friendly and smooth LSD transition. The automatic FD uses a 3.9 final drive whereas the manual version houses a 4.10 final drive. The 4.1 is a little friendlier to the FD powerband. Single turbo owners and auto x'ers often use a readily available 4.33 final drive. Toward the extreme end im sure you could easiy source a 4.56 ratio.

My plan is for stockish sequential fd with a jdm trans and a 4.33 fd ratio but your "perfect" setup depends wholly on how and how often you use your FD along with other setup variables. The stock FD drivetrain setup is not far from phenomenal and gains will be modrate but cumulative in any efforts therin.

SO do some research and some shade tree figuring and youll be plenty set to make the decisions determining the DT setup for your perfect FD.

jkinluv

Yeah, i'm a fan of matching the gear ratio with your build plans/thoughts.

If you are going to be running a big turbo, like I do on my DSM I changed to GVR4 gear cluster etc

I would think that for a bigger turbo, your stock gear ratio would be great for spool? Whereas a shorter faster gearing would be ideal for stock/modified twins or small singles?

any thoughts?

hsitko

iTrader: (1)

Well, i'm not going with a huge turbo. I have a gt35r that i'm almost done installing. So that is the power band that i'm trying to match gearing too. I will have it tuned to be making something like 350 to 380. I picked that turbo to try and match the spool characteristics of the stock twins. Now my only concern is getting one from a reputable seller that doesn't grind. I would like a late model one i think.