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4.80 or 4.77 gears anyone?

15K views 59 replies 25 participants last post by  AKADriver 
#1 ·
Just came across some 4.80 gears for the 1.8 rear end on eBay and got to searching, but didn't find much.

Anyone have experience or advice relating to a 4.80 or similar final drive swap?

My understanding is that acceleration would improve noticeably while decreasing top speed and increasing cruising rpms etc.

Just wondering if it's worth looking into and what ratios might work/where to source the gears from (i.e Kia 4.77 gears like the S2K guys use vs. the more expensive 4.80s I saw)..


Any thoughts?
 
#35 ·
i might be late to this thread

i have a 4.7 torsen in my 1994 NA. The Ring & Pinion is from a Kia (i believe kia sportage ). In my opinion its amazing. Acceleration did improve. You can feel the torque.



^ I've gone 85 mph in my miata and rpm was 4100. Nothing has changed for me. i daily my car.

So fare i love the 4.7 is amazing for me. The car feel alot faster and better coming outta corners. it smoother going through the gears. there is no hesitation/lag when your rpms are Low. my car feels way smoother and more responsive.



You wont know how it feels until you try it.
 
#4 ·
You are exactly right about what you posted (theshadow).

I don't think anyone here really plays around with their final gear. They just go with what they have.

I've done some research and a 6-speed transmission with 4.1 rear end has pretty similar shifting points as a car with a 5-speed trans and 4.77 rear end but with the addition of an overdrive gear.

If you are NA it will help but if you are F/I I've heard there is almost no use because of the torque you'll be putting out.

If I can't find a 6-speed by the time I buy a diff I'm just going to buy a 4.77 final gear too.
 
#5 ·
True - the 6 speed swap would be a nice one. Lots of possible combinations of transmissions and gears even stock (3.9, 4.1, 4.3) let alone something more extreme (4.80s, 5.xx etc.).

Just wondering how many peeps have thought of this/tried it out. Am thinking of swapping in some 4.80s to my 91 NA6 since I have a 1.8 torsen rear end that uses a 4.1 ratio.

Not sure how extreme the change would be. Would probably be awesome on track, not sure about AutoX, street might not be so bad doing 5000rpms at 70mph instead of 4000 ;)

S2Ks get great results with this anyways - even at 300-400 bucks for a new set of gears it might not be a bad way to improve acceleration while staying NA.

Ham, do you know anyone whose tried 4.77s in a Miata? :)
 
#11 ·
Seems I've got some calculations to do then.

Don't spend lots of time on the highway so not extremely bothered about cruising rpms.

Which cars can we pirate these things from for cheap? Would the same gears they use in the S2Ks work?

Apologies if I'm about to find the answers on the links people posted. Just thought this whole gear ratio thing was worth some Q&A. So far, very impressed with feedback. CR.net WINs again.
 
#13 ·
Performance wise the spec miata guys love the short gears, but for a daily driver I will stick with my stock rear end
 
#16 ·
For N/A cars, I think the 4.1 + a 6 speed is fine. Emilio has a 4.3 and a 6 speed, which I hope to do in the future.
Oh yum. Combine this with a flywheel too. :fap:
 
#20 ·
I would not limit your decision to whether you are N/A or F/I. It matters on your goals for the car. You could run the 6speed and a 4.8 rear on 22in wheels and dominate a course limiting speed to 50mph but then go to a track day and run out of gear pretty fast. Ideally using a calculator find what speeds you want to achieve most efficiently and go with them. Your gearing can get too short and too long. The cars purpose really is what matters. For example if you need 3 shifts to pull 60mph a car just needing two even if less powered might win the 0-60 race.

The two most important determining factors should be purpose and power band.
 
#22 ·
more, more, more!

I'm lovin' even the ideas bein' thrown around here. it's actually a thread with accurate information & mature replies.

I need more! so I know what options I'll have too.
 
#23 ·
I couldnt live with anything higher than the 4.1 thats in my 6 speed right now. I would personally love longer gears lol. My target rpm i want is 6gear 2.5k @ 70mph but they dont have a final drive low enou.....wait im not a vette lol
 
#24 ·
Oh I do understand on gearing betweem FI and N/A. I also agree that if you're going to be doing all-motor that shorter gearing *can* be benificial, but not always. Considering 90% of the people on here and how the cars are driven, mostly just on the street, then swapping to a short final will have more feeling behind it as you'll be rowing through the gears much more. Which is fine. But if you're thinking about adding ANY kind of FI, you'll find yourself in a hole because first will be completely useless and maybe even second if you go very short (4.6 or more). Remember, time shifting is time wasted.

kidloco- a 3.6 is about all you can easily find for the Miata diff., couple that with a slightly taller wheel and it'll help. If you really want gearing options, you can swap in a Ford 8.8 IRS...but that's a lot of work if you're not seeking out some kind of competition where gearing is that important.
But what I really want to know...is if you have a 10AE...why do you have a 4.1 when the car came with a 3.9?
 
#32 ·
I have a 6 speed and 4.10 torsen in my n/a. I run 205/50 on a 15x8 6ul. I wouldn't go any lower on gearing than the way it is now. Be incredibly lucky if i can ever max 4th in the 1/4 mile n/a and on the local tracks(njmp) I am lucky to get in 5th. There is a lot of needless shifting around town IMO
 
#33 ·
Hmm let's see..
My 90 "Baja smurf" has 5 spd 4.778 R&P W/ type 2 torsen
My 96 "Green destiny" has 6 spd 4.3 R&P W/Auburn LSD
My 93 "Terminator" has built 5 spd 4.1 R&P W/ OS Geiken LSD

I can get new R&P sets for 600$
3.6
3.9
4.1
4.3
4.4
4.666
4.778
 
#39 ·
I can get new R&P sets for 600$
3.6
3.9
4.1
4.3
4.4
4.666
4.778
There are OEM options for many of those floating around. Call your local wrecking yard especially for the 4.778. Ask for a 98-02 Kia Sportage front diff. Less than $100 later you are set.


ps I love my 4.778.

 
#37 ·
Don't forget redline is very important. A lot of the people swearing by 4.3-4.8 also have much higher redlines than stock. A 6spd+4.3 with a 8,500-9,000 redline is probably quite enjoyable.

This isn't something you can just brand "FI guys do this" "NA guys do this", it's very application specific. Even the tracks you regularly run can have a huge impact on what works for you. You could also be taking advice from someone who runs a 22" tire when you run a 23". The whole car needs to be taken into consideration. Generalities suck.

Use a calculator. Figure out where YOU want to be shifting. This ain't rocket science.
 
#38 ·
This isn't something you can just brand "FI guys do this" "NA guys do this", it's very application specific.
i was just generalizing what ive seen guys do from all the build threads ive seen, and the majority of them are street cars...

an FI guy obviously isnt going to put a 4.3:1 or a 4.7:1 in his car. and nor would an n/a guy do a 3.6:1 for his r&p (atleast in a miata)
 
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