I am getting ready to order my B16A1. The tranny I want is either the s1 or j1, because I like the gearing. Only problem is I drive about 40 highway miles to work every day. I want to change out the fifth gear so I am not burning through the gas. I looked up the gearing on the 90-92 USDM Integra and I think it would be a good highway gear. Will this 5th gear work,and if not what will.
Thanks

 

I wanna know too, since i get horrible gas milage on my s1 tranny, bump.

 

I'm not sure about the internals swapping but I know the S1/J1's have the same input shaft as the 90-91 USDM teg's. If you're looking to get better gas milage you may want to swap the JDM 4.40 final drive out for the USDM's 4.27 final drive. Overall your gearing will be a bit longer, but it will still keep the steep ratio's b/t gears.

check out this page to fool around with different trannies and thier final drives.

http://crx.honda-perf.org/math/index.html

 

ok, he got the the tranny because he liked the gearing(like me), which is like the y1 except of the final drive which is 4.23 now, if he switched this, it would be crazy, because then he'd basically have a y1 tranny, he still wants the nice accel of the 1-4 gears, but to cruise at a lower rpm in 5th, to conserve gas, and using this calculator you get 4717rpms at 80mph in fifth gear using the j1/s1 tranny, but if you change the fifth gear (using logic just keep the j1/s1 final drive and switch the tranny to a usdm s1) you get a rpm of 3860 that's quite a jump, nearly 1000 rpms. I belive this would save on gas considerably. I'm sure somebody has done it, it would be sortof like taking the crx/civic si tranny and putting the hf fifth gear in it.

 

You are exactly correct. If someone out there has done it I would be interested to know all of the parts required. Obviously 5th gear, but what other parts? Do you also order the syncro? Any other parts?

 

you can do it, i think you just need the 5th gear set, the synchro will come off with it. This is waht im doing because my car has a usdm s1 in it that grinds 1-2 2-3 so im just using the old 5th and the 1-4 of the j1

 

Since people have J1....

Can you count the teeth on the gear for the 5th gear(on both shaft),pleaze?

Should be like 29/32.

Help greatly appreciated!

 

i have a Y1 LSD with a 90-93 LS 5th gear in it. Highway cruising is pleasant.

You have to buy two parts from acura. The 5th gear main and counter gears. They cost me around $180 new.

All b-series 5th gears will fit into the Y1, S1, J1. The 94-up LS 5th gear is even longer than the 90-93, but too long for my liking.

 

So let me get it, say you have a the S1/J1 which do you think is the best for acceleration, I mean as of going NA. So you can still take the 5 th gear out and replace it with one from an LS tranny say from a 90-92 would it be able to fit. I can imagin that it should fit. Just as long as the tranny is from a b-series cable tranny. So you would need the 5th gear and what else?

 

What RPM are you running at say 70mph? Are you pulling pretty good gas milage?

 

If you have a JDM S1, J1 or Y1, You can Only use the 90-91 5th Gear, the 92+ transmissions have a different Input shaft/ Mainshaft Size.
To do the conversion You have to buy BOTH 5th gear Main and countershaft Gears.
Open up the trans, remove the mainshaft bearing, then remove the counter and mainshaft and shift forks. Undo the 32mm nut on the countershaft. Carefully pull it apart, and replace with new gears, and put it back together. In about a week or 2 I will take pictures and shwo how to do it.

 

By the way:
JDM S1 5th gear at 4K is 70 mph
Jdm Y1 5th Gear at 4K is 75 mph
Jdm J1 5th Gear at 4K is 70 mph
USDM S1 (90-91 Integra) 5th Gear at 4K is at 90 mph.
I had all 4 of these transmissions,
I like the Jdm S1 best for accerlation
Y1 Best for Road racing.
USDM S1 is the Best for TURBO applications.

 

Thats great information. Thanks. I am looking forward to seeing the pics of this. It would be a lot of help for when I tear into my tranny.