The '91 HF uses a 2.9 FD while the SI uses a 4.2 FD. Are 1st-5th gears the same with the only difference being the FD? In Honda-Challenge the gear ratios must stay the same, but the FD can be changed. I'm trying to figure out if I can just swap in a SI tranny or will I need to pull it apart. Thanks.

 

According to my book:

--------HF-----------------Si
1-----3.250-------------3.250
2-----1.650-------------1.894
3-----1.033-------------1.259
4-----0.823-------------0.937
5-----0.694-------------0.771
R-----3.153-------------3.153

FD:
HF 2.954, 3.250(Cal)
DX 3.888
Si 4.250

Hope that helps.



[Modified by blunty, 8:04 AM 12/18/2001]

 

Thank you!

 

Or you could just buy my B16A swap with the nicey J1 tranny!

You know you want it Chuckles...

 

The gearing is different. I don't remember all the specs but first gear is the same.

 

What engine do you have. If you have the HF I wouldn't worry about the gearing to much as the powerband on the HF is wide and the gearing doesn't seem to make any difference. Somebody changed the first 2 gears in my HF when I bought it and it wasn't any faster. I little more fun at times but not faster. 1st gear would go 30MPH and second would do like 55. Which for an HF isn't right. Had to redline it everytime in first gear so it would be at like 1500 RPM's when on the second shift.

 

Yes, it is an HF. What gears were installed in your HF? Changing from a 2.9 to a 4.2 is a pretty significant reduction if OE HF gears are retained.

Second question: Would a '87 SI FD fit a '91 tranny? Don't know if there are any differences. Thanks.

 

L3 tranny should work huh