if you have the jdm 4.78 in your car, can you tell me a little about them. i cant find info anywhere. how much does it lower top speed and raise rpms. how much does it lower 0-60 and 1320 times

 

I have it in my GSR sedan with USDM ITR tranny...

It was quite a difference for me since a) I hadn't driven my car in 1.5 YEARS, and b) I had stock GSR gearing.

80 MPH is ~4600 rpm. My redline is 9000, so top speed would be approx 155-160. I wouldn't worry too much about losing top speed, lol.

I think it nets a few tenths in the 1/4. Makes the car very "torquey feeling," well relatively speaking. I daily drive my car and love it so far, even with no AC and no PS. Hurts mileage and isn't so great on the hwy though. Prob a sane person wouldn't want it, lol.

Gearing does work some wonders for our TQ deficient cars IMHO though.

Cheers,

FB

 

205/40-16 tires will net a 4.59 FD on a tranny with 4.40 FD stock.
Not as good as a 4.785...but closer

 

I've got a 4.785 fd and ls 5th gear in a gsr tranny. Rpm @ 70(speed limit-hehe) are 3500-3550. Nice for noise and gas mileage(not that I really care). This is with 205/40 17 tires.

 

anyone run non-OEM FD gear with an OEM LS/GS-R fifth gear for lower freeway RPMs? Would that work?

Jon

 

I'm picking up my car today. Had a ATS 4.929 FD, ATS 1st gear, 2nd gear and an LS 5th gear. I'll let you all know tomorrow what I think.

BTW, I should drop about 600 rpms @ 70 mph from stock to the set-up above.

 

I have the JDM final gear and JDM gearbox (stock for us). I think it's the ideal combination. No problems with top speed (150 mph) and better acceleration...

 

Picked up my car and WOW is all I can say.

to Godspeed and ATS for a sweet 4.929 FD. I don't have much seat time yet but first impressions are very, very positive.

Engine feels stronger, kinda like 3rd gear now pulls like second and 4th gear pulls like 3rd, etc. I need to hook up that Z10 kit as traction is even more of an issue I bought the ATS 1st gear as well as an LS 5th gear. I would suggest the ATS 1st gear if you want to go with the 4.929 FD as it's taller than stock(2.929 vs. 3.23), and the LS 5th is gonna be sweet on the long hauls.

 

Full JDM Tranny

 

Likewise
Anyhow, highway revs are definitely higher and would be even more so if you keep the USDM ITR fifth. Personally, I'm going to compensate by getting a remote oil cooler to make sure my engine temp stays down.

BTW, I love how tight the JDM gearing is.

 

pardon the dumb question but, what exactly does an aftermarket or JDM final drive do?