Honda Manual Transmission Specifications & Gear Ratios

[Mista Bone]

Originally Posted by Bense

*waves hello

*waves back to Andrew

[California98Civic]

Originally Posted by Mista Bone

*waves back to Andrew

Grateful for info... will definitely contact you through PM soon and update this thread. Thx!

[suspendedhatch]

You have 2nd gear on the D16y engines listed as 1.782. By my count, earlier D15s have 37 and 21 teeth on their 2nd main and counter gears, resulting in a ratio of 1.762.

What combination of teeth gets you to 1.782?

[Ecky]

Just looked up and it looks like the Insight 5th gear is drop-in for the first-gen Fit, possibly second gen as well. The needle bearing for both of them is 35x39x24mm. This would drop 5th gear from 0.757 to 0.710 and highway cruising RPM (65mph) from 3100rpm to 2900rpm - not huge, but 6.5% is nothing to sneeze at.

My guess is that both gear shafts would probably drop in with minimal modification, but I don't think the Fit is appropriately powered to go from a 4.3 FD to a 3.2.

I just happen to have an Insight transmission laying around.

[California98Civic]

First, my apologies that it took so long to update the OP. Busy and then crazy times intervened and I forgot. I respond below and have edited the OP.

Originally Posted by Mista Bone

before I read through all the posts, the original post needs some updating/correction. I might have made them before, but I haven't been on Ecomodder in some time, the CRX has been retired.

88-91 Civic DX LX / CRX

3.722 was 88 only, 89-91 was 3.889

Done. Used this comment for citation in the bibliography at the end of the OP.

Originally Posted by Mista Bone

All 1992-2000 trans have one of two speedo gears: EX/Si/HX use “big bore” black one and others use white one but outer diameter is the same. Honda used white big bore (40mm) speedo gear in the 88-89 transmissions, but also a few have shown up in 96-00 EX transmissions, seems Honda was raiding the left over parts bin.

Added this, too, with citation to you.

Originally Posted by Mista Bone

98-00 EX HB
Those didn't exist in USDM market, might be a CDM chassis/trans? Were they 35mm (small bore) like the 90-91 EX Sedan's or 40mm (big bore) like the 92-00 USDM? Quaife never got their info correct.

Thanks for the correction. Nice catch.

Originally Posted by Mista Bone

California98Civic, if you need more info, a PM should work and get to my email address. Thanks for the work! -Mista Bone "D" tranny guru

Will do. Thanks.

Originally Posted by Mista Bone

PS: Those casting codes and 35mm vs. 40mm info, those were found out when I had 15-20 transmissions in the three seasons room at my old house 20+ years ago.

You have sold all of that inventory by now, I guess, yes?

Originally Posted by suspendedhatch

You have 2nd gear on the D16y engines listed as 1.782. By my count, earlier D15s have 37 and 21 teeth on their 2nd main and counter gears, resulting in a ratio of 1.762. What combination of teeth gets you to 1.782?

That number is from a cited source, not my personal counting. I have not counted teeth on my old DX (D16y7) transmission (yet). I will at some point and keep this question in mind.

Originally Posted by Ecky

Just looked up and it looks like the Insight 5th gear is drop-in for the first-gen Fit, possibly second gen as well. The needle bearing for both of them is 35x39x24mm. This would drop 5th gear from 0.757 to 0.710 and highway cruising RPM (65mph) from 3100rpm to 2900rpm - not huge, but 6.5% is nothing to sneeze at. My guess is that both gear shafts would probably drop in with minimal modification, but I don't think the Fit is appropriately powered to go from a 4.3 FD to a 3.2.

This is interesting, but I wonder... Doesn't the Fit have the transmission on the driver side of the engine? The gears would be cut with opposite rotation in mind, no?

[Ecky]

Originally Posted by California98Civic

This is interesting, but I wonder... Doesn't the Fit have the transmission on the driver side of the engine? The gears would be cut with opposite rotation in mind, no?

Nope! The Insight's ECA1 engine is basically the prototype L series engine that's in the Fit. The bell housing is the same on the transmission, the mounts are generally the same, the Insight engine is just one cylinder short and lacks VVT.

One might also look at it as the Insight engine being the first design in the line of engines that are now in basically every Honda - even the CR-V's turbo 1.5 has a lot of compatible parts and similar geometry.

[M_a_t_t]

Was there a reason you have the chart starting with the fourth gen?

If only because you don't have the numbers for 1, 2, and 3, I can help with 1

1st 3.000
2nd 1.789
3rd 1.182
4th .846
Reverse 2.916
Final 4.933

And I know this thread is for manual transmissions, but if anyone is curious here is the ratios for the Honda-matic 2 speed

1st 1.521
2nd 1.034
Reverse 2.045
Final 4.117

I will post a scan of the book soon for documentation.

https://drive.google.com/file/d/1Zk6...ew?usp=sharing

[California98Civic]

Thanks for these adds, guys. It could be fun to expand this OP into a wider online resource for Honda manual transmissions, from first gen civic through at least seventh gen. I guess my current 4th through 7th Gen with the Civic is to focus on D-series engines, where I started, with my car. I was sticking with the FE cars. Maybe adding more L engines would be smart. My list is different from others that used to be online in that it emphasized transmission swaps that were for the FE cars rather than the ones dudes prefered to swap for "racing" fun. I'll edit the OP further soon.

[Ecky]

Honda transmission gurus, I have a question.

At some point I might be interested in making Aerocivic's gearing even taller. Looking at the charts, the 88-91 HF has the tallest ratios possible, and would result in a 10.3% reduction in RPM in 5th gear. 1.2% of this is from 5th gear being slightly taller, and the other 9% is from the final drive.

The notes say that the countershaft is shorter for the 88-91 CRX than in 92-00 Civics, and the countershaft is part of the final drive (FD is the ratio of the countershaft and ring gear on the diff). This suggests to me that I cannot swap the final drive from the CRX HF into the Civic gearbox, and the 5th gear alone would be virtually meaningless.

Meaning, if I want the HF gears in Aerocivic, I probably need to put in the complete HF gearbox.

Where this is difficult:

-The differential might not be in the same spot, meaning the axles may not be the right length anymore.
-The transmission mount will be different. I can fabricate this though.
-The shift linkages might not bolt up / work
-The bits that mount on top of the transmission (e.g. airbox) likely will not have anything to bolt onto
-Cable to hydro conversion would be required at the transmission
-VSS will need correction. Hopefully it's electrically the same.

Anyone have details on any of these points for me?

[Gasoline Fumes]

Originally Posted by Ecky

Honda transmission gurus, I have a question.

At some point I might be interested in making Aerocivic's gearing even taller. Looking at the charts, the 88-91 HF has the tallest ratios possible, and would result in a 10.3% reduction in RPM in 5th gear. 1.2% of this is from 5th gear being slightly taller, and the other 9% is from the final drive.

The notes say that the countershaft is shorter for the 88-91 CRX than in 92-00 Civics, and the countershaft is part of the final drive (FD is the ratio of the countershaft and ring gear on the diff). This suggests to me that I cannot swap the final drive from the CRX HF into the Civic gearbox, and the 5th gear alone would be virtually meaningless.

Meaning, if I want the HF gears in Aerocivic, I probably need to put in the complete HF gearbox.

Where this is difficult:

-The differential might not be in the same spot, meaning the axles may not be the right length anymore.
-The transmission mount will be different. I can fabricate this though.
-The shift linkages might not bolt up / work
-The bits that mount on top of the transmission (e.g. airbox) likely will not have anything to bolt onto
-Cable to hydro conversion would be required at the transmission
-VSS will need correction. Hopefully it's electrically the same.

Anyone have details on any of these points for me?

The HF box is really tall. I loved it in my Civic Wagon. I think 60 MPH was 1800 RPM. I usually cruised at around 1200 RPM. At higher speeds, I still wanted even taller gearing! My one complaint is that it has a similarly weird 1-2 gear spacing as the Insight. Big RPM drop into 2nd gear. I'd prefer the regular Civic 2nd, 3rd, and 4th with the HF 5th and final.

Does the 5G Civic have a VSS? The HF box has a mechanical speedo cable.

The input splines are something to keep in mind when sourcing the HF box. The 89-91 box is probably easier to use. From what I've read, the '88 box can be used, but might require mixing and matching clutch parts.
88 = 21 splines
89-91 = 20 splines