Civic Tranny Swap?

[civic lover]

I just bought a 97' Civic HX. Has anyone on here swaped in a VX trans or possible a HF gears in their HX? Give me some insite because I want to compete with the VX's.

[beb]

I'm not verifying any of this, it's just off the top of my head, so consider it blather until checked:

It's a 5-spd, right, not the CVT? The EK's S40 transmission is supposed to be stronger than the EG's S20 (steel vs aluminum shift forks, some larger bearings), so it might be a better match to your HX's 125 HP D16Y5 than anything that was mated with the tallest-geared S20 (92 HP D15Z1, 70 HP D15B8). About the only difference in gearing is that the S20 in the VX and CX had a 3.250 final drive, while the S40's in the HX is 3.722 - which is considerable. I don't know if the final drive gears from an S20 can be put in an S40 (I'm still looking into this), but if so then that would be an attractive option.

The non-CA HF transmission has a 2.95 FD and a slightly taller 5th gear too, but is cable actuated. I've seen converters for going the other way, but there might be kits to allow a cable tranny to hook up to a hydraulic clutch pedal.

One issue that I'd like to know more about when changing to a transmission with different gearings is how the ECU will behave. Purportedly, it is able to tell what gear you're in from the ratio between the tach and VSS signals, which will forever cease to match again if a differently geared transmission is put in.

[civic lover]

Originally Posted by beb

I'm not verifying any of this, it's just off the top of my head, so consider it blather until checked:

It's a 5-spd, right, not the CVT? The EK's S40 transmission is supposed to be stronger than the EG's S20 (steel vs aluminum shift forks, some larger bearings), so it might be a better match to your HX's 125 HP D16Y5 than anything that was mated with the tallest-geared S20 (92 HP D15Z1, 70 HP D15B8). About the only difference in gearing is that the S20 in the VX and CX had a 3.250 final drive, while the S40's in the HX is 3.722 - which is considerable. I don't know if the final drive gears from an S20 can be put in an S40 (I'm still looking into this), but if so then that would be an attractive option.

The non-CA HF transmission has a 2.95 FD and a slightly taller 5th gear too, but is cable actuated. I've seen converters for going the other way, but there might be kits to allow a cable tranny to hook up to a hydraulic clutch pedal.

One issue that I'd like to know more about when changing to a transmission with different gearings is how the ECU will behave. Purportedly, it is able to tell what gear you're in from the ratio between the tach and VSS signals, which will forever cease to match again if a differently geared transmission is put in.

Sorry... Yes it is a 5 speed. I guess I didn't know that the ecu cared what gear ratio it had in the tranny. As far as I know I could do a final drive swap. I did one in my current Civic and it was easy.

[beb]

Originally Posted by civic lover

... a final drive swap. I did one in my current Civic and it was easy.

I'd like to learn more about doing a FD swap - what was involved in that, just pull the tranny apart and swap out the ring gear and its driver; any shimming involved in that? What year Civic was it? Where did you get the new/donor FD parts?

[civic lover]

Originally Posted by beb

I'd like to learn more about doing a FD swap - what was involved in that, just pull the tranny apart and swap out the ring gear and its driver; any shimming involved in that? What year Civic was it? Where did you get the new/donor FD parts?

Well I just had two trannys sitting there and I wanted to make a hybrid. This is nice because you can take one apart at a time. If you make a mistake you can look at the other one. It has been a couple years since I have done it. There was no shimming involved. Just take out the final drive and swap it in the other one. It was a 88-91 Civic. I will do a write up on it next time I do it. I have to undo my hybrid tranny because I want my hf tranny back before I sell the car.