4.875 final drive review

[Dustin]

^^^^^^^^ I used his kit. Can not beat his prices.

[RehabJeff86]

Just to share a key point - For track purpose, 4.56 is ideal because u never want to hit the 6th gear

[Roxy86]

Great review.

Considering the 4.56. Sounds like a happy medium

[jamesm]

I'm still waiting for someone to come out with taller gears for us FI guys.

[juliog]

Originally Posted by RehabJeff86

Just to share a key point - For track purpose, 4.56 is ideal because u never want to hit the 6th gear

It depends on the track. At ACS/Fontana in SoCal, faster guys already hit the limiter on 5th gear (~130 MPH) with stock power and gearing .

[Dustin]

Originally Posted by jamesm

I'm still waiting for someone to come out with taller gears for us FI guys.

OEM Toyota part numbers that you can use. Obviously you would want under a 4.10 for taller gearing.

41201-80125 : 3.58
41201-80050 : 3.73
41201-80052 : 3.91
41201-19605 : 4.10
41201-29606 : 4.30
41201-19557 : 4.56

You can also give Spence at Weir Performance a call. He has many options available, both taller and shorter, and as I said before, you can not beat his prices.

[skye67]

Would like to see you 0 to 60 and quarter mile time with the new gearing.

[xwd]

Originally Posted by Dustin

OEM Toyota part numbers that you can use. Obviously you would want under a 4.10 for taller gearing.

41201-80125 : 3.58
41201-80050 : 3.73
41201-80052 : 3.91
41201-19605 : 4.10
41201-29606 : 4.30
41201-19557 : 4.56

You can also give Spence at Weir Performance a call. He has many options available, both taller and shorter, and as I said before, you can not beat his prices.

Yeah I was contemplating doing a 3.73 or 3.91 when I go turbo, mainly for autocross where the top speed you hit is usually about 70mph, but that's on really open national courses. 3.91 you can hit about 65mph at 7800RPM in 2nd. 3.73 about 68. I think the 3.91 is a good middle ground, and I'd just install the final drive the same time I did a better LSD. Maybe run the motor up to 8K, but cut boost above 7400 to something fairly low. The tire size I'm looking to run may add a couple mph as well.

[DJCarbine]

I swapped from a 2.93 to a 3.91 in my previous bmw..... it was a LOT of fun, even though highway cruising @75 was close to 4K rpm lol

The amount of fun you have at lower speeds is great

[drift86]

Originally Posted by skye67

Would like to see you 0 to 60 and quarter mile time with the new gearing.

0 - 60 will definitely be slower because there is another shift and each shift adds about 0.5secs.

When I get a chance, I'll post up some acceleration graphs comparing before and after in the first 3 gears.

[fooddude]

Just thought about something....since people usually post the ubiquitous catback exhaust video sound clips...people should also start posting videos of their cars with shorter FD's driving around the city and also on the highway

The exh/engine sound, speed and rpm would give us(the people interested in upgrading to a shorter FD) a good clue how it might behave as a DD

[drift86]

Originally Posted by fooddude

Just thought about something....since people usually post the ubiquitous catback exhaust video sound clips...people should also start posting videos of their cars with shorter FD's driving around the city and also on the highway

The exh/engine sound, speed and rpm would give us(the people interested in upgrading to a shorter FD) a good clue how it might behave as a DD

I looked long and hard and couldn't find any videos either, except for the TRD Griffon which has the 4.8. [ame="https://www.youtube.com/watch?v=iGFHgbe0Epw"]86 TRD Griffon Concept（タイãƒ*アタックãƒ*ービー） - YouTube[/ame]

There are a number of videos of s2000s with final drive mods like this one: [ame="https://www.youtube.com/watch?v=DnlUGCmFKjc"]Honda S2000 4.77 final drive before and after video racing a supercharged civic - YouTube[/ame]

I'll say the 4.56 has basically no downside. 11% higher rpms really doesn't make the car any louder at all especially at lower rpms.

The nice thing about modifying the final drive on a DD is that it is the type of mod that becomes more pronounced the harder you drive. If you are driving gently and shifting at low rpms, then the difference is minor. If you are shifting at redline, the difference is bigger.

I was surprised at how usable the 4.875 is on a DD. It sounds like an extreme mod, but its not at all from my experience. When driving gently, I'm not shifting more than before and in some cases I can shift less because I can use 3rd gear to pull away from a crawl at intersections using the increased torque. Also, first gear is still entirely usable and can put the full power to the ground without wheelspin.

IMO a loud exhaust is actually a lot more intrusive than this mod on a DD.

[CajunFRS]

Originally Posted by drift86

0 - 60 will definitely be slower because there is another shift and each shift adds about 0.5secs.

When I get a chance, I'll post up some acceleration graphs comparing before and after in the first 3 gears.

You sure about that? Wouldn't it also accelerate faster?

[wootwoot]

It will accelerate faster but likely be slower from 0-60 because you have to shift into an additional gear. The shift takes time to complete, and the time you lose shifting is greater than the time you gain with the new final drive.