Gear Ratio Calculator

[EricW]

http://www.fatboyraceworks.com/gears/
Gear ratios for a carb 86 transmission
Final Drive Ratio 3.866
1st Gear 3.181
2nd Gear 1.842
3rd Gear 1.208
4th Gear 0.878
5th Gear 0.694

Just for you guys to amuse yourselves. According to it I could do 140mph in 4th and up to 180mph in 5th with the red line at 6850.

[DDRaptor]

err. that seems so weird it says only 32mph in first and only 55 in second.

then again i have an auto I get to 35-38 in first and close to 65 in second .

[EricW]

Did you set the correct rev limit, tire size, and correct gear ratios. I just gave the one for the manual carb 86 tranny.

[2ndGenGuy]

You have GOT to love those extra tall economy gears. They are good for something: top speed... Of course you better have some power to get up there!

[MessyHonda]

i have a question.


i plan on doing the integra gear swap.

i only want to use the 1-4 and then an carb accord 5th gear. would the final drive change since in carb is like 3.8 and fuel injected like 4.0

[DDRaptor]

we don't have a rev limit and on my 88 i can rev past redline, but i set it to 6500rpm and i remember my tire size being 185/70 r13 but i don't know my auto's gear ratio so i used the ones you posted for the manual tranny.

[EricW]

Automatic 88 trans is
1st 2.529
2nd 1.481
3rd 1.030
4th 0.700

final 4.066

[EricW]

i have a question.


i plan on doing the integra gear swap.

i only want to use the 1-4 and then an carb accord 5th gear. would the final drive change since in carb is like 3.8 and fuel injected like 4.0

Only if you change it.

[MessyHonda]

Only if you change it.

what do you mean? im not really sure how the final drive works. so does that mean i still use the accord final drive or the integra one?


for the carb accord its like 3.866 and for the integra one is 4.214

[A18A]

i thought the final drive was the diff or something

i bet this post is gonna make me look stupid

[DDRaptor]

185/70 R13
max rpm 6500

1st 2.529 93.21 mph
2nd 1.481 159.16 mph
3rd 1.030 228.85 mph
4th 0.700 336.74 mph

final 1.904

huh i put all the above values and got those results before i changed the final drive from 4.4 it was reading 1st at around 40mph which is about right but when i changed the final drive ratio it went crazy.

[EricW]

what do you mean? im not really sure how the final drive works. so does that mean i still use the accord final drive or the integra one?
for the carb accord its like 3.866 and for the integra one is 4.214

Sorry I've never dissected a tranny, so this is going from the pictures in the manual. I believe the final drive is a gear at the base of the counter shaft that drives the one on the differential. It would probably help to talk to someone who has done it before since I'm one of the hands on type who take it apart to see how it works and put it back together. But that's my best guess since every gear is actually a pair of gears in the transmission.

[EricW]

final 1.904

sorry I accedentaly put the revers in when i was looking at the final drive. oops I changed it to the correct value above.

[MessyHonda]

Sorry I've never dissected a tranny, so this is going from the pictures in the manual. I believe the final drive is a gear at the base of the counter shaft that drives the one on the differential. It would probably help to talk to someone who has done it before since I'm one of the hands on type who take it apart to see how it works and put it back together. But that's my best guess since every gear is actually a pair of gears in the transmission.

alright maybe the tranny gods can help me out.

[2ndGenGuy]

The final drive is the ratio between the main output of the gearset and the axles. So it's basically your differential ratio. Changing gears 1-5 won't change your final drive.

[MessyHonda]

The final drive is the ratio between the main output of the gearset and the axles. So it's basically your differential ratio. Changing gears 1-5 won't change your final drive.

so if i use a carb tranny im stuck with a 3.866 final drive ratio even tho i have the 1-4 teg gears?

[2ndGenGuy]

Yep. Toss a Prelude or Teg diff in there, and you'll get a better final drive ratio. That's what makes the gears shorter overall. The difference between gears 1-5 in my Prelude tranny aren't a whole lot different from my Accord tranny, but the final drive is what makes the biggest difference.

[MessyHonda]

Yep. Toss a Prelude or Teg diff in there, and you'll get a better final drive ratio. That's what makes the gears shorter overall. The difference between gears 1-5 in my Prelude tranny aren't a whole lot different from my Accord tranny, but the final drive is what makes the biggest difference.

man that really sucks. i want 1-4 short gears but a tall 5th gear since i have to daily drive 70 miles every day and 65 of them are like freeway miles and it would keep the engine at low RPMs cuz high RPMs suck with an exhuast.

[evil88accordLX]

okay, so isnt the way it works: multiply the gear and the final drive to get how many times the engine must turn over to rotate the tires one full rotation? for example, 3.181 (first gear) X 3.866 (final drive) = 12.29775 engine rotations for 1 tire rotation. this would make sense bacause for fifth gear it would be 0.694 X 3.866 = 2.683004. if you do it in reverse using tire diameter, you can divide the feet in a mile by tire diameter and get the number of rotations the tire must do to travel a mile. so a 22" tire (approx. 6'-0" diameter) must rotate 880 times to travel a mile. now take the 880 and multiply it by 2.683004 (5th gear X final drive) and you get approx. 2361 rpm at 60 MPH.

[2ndGenGuy]

Bam, that sounds about right to me. ^^^

The Integra 1-4 gears will still be shorter. And using an Accord 5th will still be better than an Integra or Prelude 5th. You just gotta find a final drive that you like the best. Accord final drive will make ALL the gears longer than the Integra final drive... Messy, do you have a link to the Integra gear ratios?

[MessyHonda]

Bam, that sounds about right to me. ^^^

The Integra 1-4 gears will still be shorter. And using an Accord 5th will still be better than an Integra or Prelude 5th. You just gotta find a final drive that you like the best. Accord final drive will make ALL the gears longer than the Integra final drive... Messy, do you have a link to the Integra gear ratios?

accord (86-89) integra (86-89)
1st 3.272 3.181
2nd 1.842 1.944
3rd 1.208 1.347
4th 0.878 1.033
5th 0.694 0.848
R 3.000 3.000
Final 4.066 4.214

the 86-89 accord carb has a 3.866 Final.


my plan was to put in the teg gears with the carb final....but that just leaves me with almost a fuel injtected tranny with the 4.066 final

[2ndGenGuy]

If you do the Integra tranny with Accord 5-speed, you end up with something like this:

3.181
1.944
1.347
1.033
0.694
FD: 4.214

That's going to be one hell of a change from 4th to 5th.

Here's the lowdown on your parts you're thinking of doing, thanks to the help of the calculator:

Acura Integra Stock:
Top Speed: 140mph @ 7000RPM
RPM @ 65MPH: 3400

Honda Accord Stock:
Top Speed: 159mph @ 6250RPM
RPM @ 65MPH: 2550

Accord with Full Integra Gearbox
Top Speed: 120MPH @ 6250RPM
RPM @ 65MPH: 3400

Accord with Integra Gearbox and Accord 5th Gear
Top Speed: 146MPH @ 6250RPM
RPM @ 65MPH: 2775

So you can see that by swapping the Integra 1-4 only, isn't going to make that much difference. What you need to do is get the Integra gearbox, and put the Accord 5th gear on it. It will only bring you up 200RPM in 5th gear, and should make the rest of your gears rock.

EDIT: I think these may be slightly inaccurate. I was using that calculator that was linked, and noticed that when I changed the FD ratio, it wasn't changing the numbers for each gear. This should still give you a good idea of what's up though. I'll check on it tonight when I get home, I've spend entirely too much time as it is on this at work.

And regardless of what you decide, if you're tearing apart the tranny, might as well toss in an LSD while you're at it. The Phantom Grip will go on the Accord diff, according to PhydeauX, so if you don't like the short-ass Integra final drive, you can still get an LSD. Or even get what you want from OPM.

[EricW]

EDIT: I think these may be slightly inaccurate. I was using that calculator that was linked, and noticed that when I changed the FD ratio, it wasn't changing the numbers for each gear. This should still give you a good idea of what's up though. I'll check on it tonight when I get home, I've spend entirely too much time as it is on this at work.

you have to hit the calculate/graph button at the bottom of the page when you change the final drive.

[2ndGenGuy]

Even after that though, the speeds didn't seem to change. Maybe it was the javascript used in the page wasn't 100% compatible with Firefox on the Mac or something crazy. But I double-checked the numbers anyways, and they do look accurate.

[MessyHonda]

If you do the Integra tranny with Accord 5-speed, you end up with something like this:

3.181
1.944
1.347
1.033
0.694
FD: 4.214

That's going to be one hell of a change from 4th to 5th.

Here's the lowdown on your parts you're thinking of doing, thanks to the help of the calculator:

Acura Integra Stock:
Top Speed: 140mph @ 7000RPM
RPM @ 65MPH: 3400

Honda Accord Stock:
Top Speed: 159mph @ 6250RPM
RPM @ 65MPH: 2550

Accord with Full Integra Gearbox
Top Speed: 120MPH @ 6250RPM
RPM @ 65MPH: 3400

Accord with Integra Gearbox and Accord 5th Gear
Top Speed: 146MPH @ 6250RPM
RPM @ 65MPH: 2775

So you can see that by swapping the Integra 1-4 only, isn't going to make that much difference. What you need to do is get the Integra gearbox, and put the Accord 5th gear on it. It will only bring you up 200RPM in 5th gear, and should make the rest of your gears rock.

EDIT: I think these may be slightly inaccurate. I was using that calculator that was linked, and noticed that when I changed the FD ratio, it wasn't changing the numbers for each gear. This should still give you a good idea of what's up though. I'll check on it tonight when I get home, I've spend entirely too much time as it is on this at work.

And regardless of what you decide, if you're tearing apart the tranny, might as well toss in an LSD while you're at it. The Phantom Grip will go on the Accord diff, according to PhydeauX, so if you don't like the short-ass Integra final drive, you can still get an LSD. Or even get what you want from OPM.

yeah so changing just the gears wont help that much.

I plan on reving my car more than 6250 tho...come on....the stage 2 cam will be only kicking in by that time. Im thinking like 7000 max rpm hope the bottom end likes it.I am going OBD1 so hope my buddy get a good tune on the car so i dont blow it up. if not its time to save up more money and rebuild the bottom end also. I was checking out the Phantom Grip and im not sure what model fits our diferencials but its 330 buck with the upgraded spring kit...sounds like a good price but im not sure if my 109whp will be doing 1 leged burn outs just yet.


im also going to get lower profile and lighter tires and rims so it helps out a bit more.