4.875 final drive review

[Lunatic]

With my 4.88s, and auto tranny, at 70 mph with cruiz control on I get 30 to 32 mpg.

[semis]

Originally Posted by Lunatic

I said it before and I'll say it again, couldn't be happier with my AT 4.88 gearing. It's perfect for the AT.

do you use stock 17' wheels?

[Lunatic]

Originally Posted by semis

do you use stock 17' wheels?

Aftermarket 17" wheels.

[Impureclient]

Got a quote of $300 for labor if I take the pumpkin out and $600 if it's in there. Does that sound right?

[KoolBRZ]

Originally Posted by Impureclient

Got a quote of $300 for labor if I take the pumpkin out and $600 if it's in there. Does that sound right?

You are adding in the cost of putting your car on a lift, storing it, and finishing it fast enough to get your car off the lot to put another one in it's place. The important part of the quote is how long would it take. Since they don't need to get your car out of there, they might not be in any hurry to finish the job.

[shaynek]

Originally Posted by KoolBRZ

You are adding in the cost of putting your car on a lift, storing it, and finishing it fast enough to get your car off the lot to put another one in it's place. The important part of the quote is how long would it take. Since they don't need to get your car out of there, they might not be in any hurry to finish the job.

at 75mph what's your rpm at? I think i may go your route kool

[KoolBRZ]

I actually have a 4.30 FD right now, since I am FI with a Phantom SC. With a lot of self-discipline I can still get over a 30 mpg average. I drive a lot. I fill up about twice a week. Since you are in California, most of your mileage is probably idling at a dead-stop, waiting for traffic to move, so I would suggest a 5.71 FD instead. Forget about shifting manually though. 1st gear redlines at 5mph!

[shaynek]

Originally Posted by KoolBRZ

I actually have a 4.30 FD right now, since I am FI with a Phantom SC. With a lot of self-discipline I can still get over a 30 mpg average. I drive a lot. I fill up about twice a week. Since you are in California, most of your mileage is probably idling at a dead-stop, waiting for traffic to move, so I would suggest a 5.71 FD instead. Forget about shifting manually though. 1st gear redlines at 5mph!

lol actually traffic isn't too bad here in sacramento. LA on the other hand 5mph sounds about right. how do you like the set up with the phantom?

[KoolBRZ]

It's a good setup with the right tune. Shiv's ESC tunes were just to blah, blah, blah, blah, oh sh!t! In other words, the power is all up high, not enough low-end torque. I haven't really enjoyed it until I made the Shredder tune.

[mrbbs]

Originally Posted by drift86

I don't know the part number. But it comes in a box with all the parts required for the rebuild. Its not just a crown and pinion.

Thanks for the review. I used to have a Cusco 4.556 on my 2013 GT86. Now I'm planning to buy a 2017 BRZ and would step up to 4.875.

Do you know what extra parts are in there, maybe you have a picture of the parts? Will it fit the standard diff housing? Can I combine it with my OS Giken SuperLock LSD?

Cheers!

[KoolBRZ]

I've had my 4.88 FD back in for about a month now. I bought a 2nd rear carrier used, to put my 4.88 ring and pinion in. That way I can change it back to the 4.30 FD anytime I feel like.
I immediately noticed the way it runs and drives was off. After some trial and error I settled on a tune with 2 points less Exhaust overlap, and 1 point less Intake overlap. I would never have thought that changing the load on my engine would require changing the tune.
Now, with the right tune, I can get up to 36 MPG highway @ 60 MPH, and up to 32 MPG @ 70 MPH.
City driving is much more fun also. I've found a new method of accelerating hard while short-shifting, I know it sounds like a contradiction, but it works if I can shift before the torque converter locks. I never thought this engine could pull hard and fast below 3000 RPM's, but it can!
I used to have to use 3rd gear for a high acceleration passing maneuver on the highway, but now 4th gear works, like having a jet assisted take off, from 55 to 105 in a matter of seconds.
Another unforeseen advantage of the 4.88 FD is my comfort in the passenger seat. My wife drives sometimes, and I usually grit my teeth and keep my mouth shut, but I actually enjoyed myself the last time she drove. In other words, it works better when the shifter is in "auto" mode as well.

[mrbbs]

Does anyone know the Toyota part number for the 4.875 final drive? Would be greatly appreciated

[avishenoy1]

Originally Posted by Tye300

You are right about the ratios. What I am trying to say is that the MT can downshift to the selected gear before and during braking because you can push the clutch in. With the AT it has to be brake, wait for the revs to come down a bit, then downshift. I have a lot of vids that shows the beep sound the car makes when it says you can't downshift. I have to click the paddle again a few seconds later to get it to downshift to my preferred gear which takes a few secs off my time. Where as in an MT, the downshift is instantaneous.
To simplify it, you can engine brake into a corner in an MT, and the AT won't let you do it in track applications.
To get back on topic, if they make a program change to the AT ecu which will allow you to downshift in high RPMs, then an AT with a 4.88 or 5.1 FD could be a track star. As of now though, the MT is at an advantage. You could play with FD ratios all day but the AT ecu is the weak link. That's coming from an AT owner.

Ive had this issue on track as well where I try to select a lower gear and get the beep because the rpm is too high.

You're right that you could downshift with an MT at that point but you would be putting severe stress on the engine because you are unable to rev match.

Also, if your revs are high enough to lock out a lower gear your already getting a significant amount of engine braking already. I doubt that MT drivers are gaining 1-2 seconds simply because they're not locked out of lower gears, but I guess it depends on the track.

[n0thing]

what is the 4.875 toyota (autofactory equivalent) part#? thanks