I have been looking at Honda tranny info for the last couple of days and I think I might have something figured out but not sure about compatibility.

The car has a B20 turbo with LS head and LS tranny. I know how everyone loves to bash the LS tranny but I cant run the V-tech trannies becasue I dont want to have to pull 5th.

Right now with the LS tranny with shift points at 8k rpm the drop is pretty dramatic as you well know. 1-2 is 4700, 2-3 is 5300, and 3-4 is 6k. If I were to put the 1st, 2nd and 3rd from the Y1 and keep 4th from the S1 it would be 5200, 5500, and 5450 respectively. Peak torque in the car is right around 5500 and it is making over 400 HP to 8k, the car is trapping in the 130's on a 23.9" tall tire.

So my questions is, are the Y1 and S1 parts interchangeable? If so, is it worth the effort for the few hundred rpm gain on the shifts? And finally, what is a good source for the Y1 tranny?

I know the gear ration info is correct for the S1 because the last time the tranny was apart I counted the teeth since there is so much bogus info on the net. The info I was using for the Y1 is 1st 3.166, 2nd 2.052, and 3rd 1.416.

Thanks for any help with this, Jim.

 

A little more info since I got the dyno sheet.

4700 rpm is 250tq and 225hp
5200 rpm is 325tq and 325hp
5500 rpm is 340tq and 360hp

 

The gears are interchangable,or at least should be.Ive swapped in y1 internals into a s1..i havent chagned the gears youre asking about,i have only changed 5th gear and it swapped over without any problem,so i dont see why the others wouldnt work the same,Just make sure for every gear you change,you use the correct counter gear.

 

uh oh - we are all in trouble now - he is figuring out how to keep the car in the powerband

the gears themselves are interchangable and you are definatley in the right track mix matching the gears - i know some people that have had very good luck doing exactly this - just a matter of figuring out where you want the rpm's to be in each gear

 

[QUOTE=B20T CRX]So my questions is, are the Y1 and S1 parts interchangeable? If so, is it worth the effort for the few hundred rpm gain on the shifts? And finally, what is a good source for the Y1 tranny?QUOTE]
jim, the ring gears from the y1 and the s1 are not alike. that also makes the splines, on their mainshafts different from each other. and since the 1/2 gears(two halfs to every gear) are fixed on the mainshaft, that means that you just can't swap these two gears from one tranny to the other . i hope you understand what i'm saying so far, it can get a bit confusing.