how to: itr tranny rebuild and upgrade

[Black R]

Oh, here's the ratios of the gears if you're curious:

1st = 3.077
2nd = 2.105
3rd = 1.652
4th = 1.308
5th = 1.033

1st -> 2nd = 0.684
2nd -> 3rd = 0.784
3rd -> 4th = 0.792
4th -> 5th = 0.790

0.784 * 8500 = 6664 rpm

rpms will be between 6600 - 8500 the whole way (except 1st -> 2nd)

actually, the rpm drop will be moved to a higher window - as the rev limiter is 9500... A 9200 shift point should land it around 7200 in all of the upper gears.


Compare this with the jdm and usdm gearing...


usdm itr:

1st 3.2310
2nd 2.1050
3rd 1.4580
4th 1.1070
5th 0.8480
final 4.40


jdm itr:
1st 3.2310
2nd 2.1050
3rd 1.4580
4th 1.0340
5th 0.7880
final 4.7860

[Black R]

More progress:

Machining the 4th gear another mm or so:





Measuring the inner ring of 5th gear on the countershaft side for a custom spacer...



J, making cnc program to do a new snap fit spacer to keep the correct distance between 4th and 5th:









Then he sets up the cnc machine and the bits that will be used:



























Custom spacer done (17-4 stainless steel):





Checking the fitment:



Final once-over on the gear to get the burrs off:



Finished:

[Black R]

Here's some more info on the tranny and gearing + costs.....

B18c5 tranny with ATS final drive and ats 1,2,3,4,5 gearset:

Gear Ratio Final MPH @ 9200 RPM @ 80 MPH

1 - 3.077 - 15.18 - 42.2 - 17423
2 - 2.105 - 10.35 - 62.0 - 11879
3 - 1.652 - 8.13 - 78.9 - 9334
4 - 1.308 - 6.46 - 99.3 - 7410
5 - 1.033 - 5.08 - 126.3 - 5827
Axle ratio - 4.929
Tire diameter - 23.44" (I did this with a 205/50/15 tire as an example.)

ATS gear ratios can be found here:

http://www.a-t-s-usa.com/ats-p...shtml


Here's an online calculator, so you can do your own comparison's:

http://www.xse.com/leres/ss/calculator.html


Cost, iirc was something like ~$800 for the gearset from a 'reputable' individual seller; but I couldn't use 1st because it was for a 4.4 final. So I had to buy a new ats 1st gear for 4.9 final ($350) and I also had to machine the 4th gear down and modify it. My buddy did those modifications for free, but I gave him a few $ for his trouble anyway. New, the gearset is in the $1200 range iirc, but then again MFactory sells a similar gearset for a lot less $. I'd look into that if I had it to do all over again.

Bearings, syncro sets, seals, and shift forks, etc, ended up costing me over $1k by the time it was all said and done.

The ats 4.9 final drive and ats lsd I already had from before I blew up the clutch. So if you wanted to have a full ats tranny like this, you're looking at a lot of $ retail.

Is it worth it? Probably not. :P

[Black R]

update:
















































well it's done! Right after finishing the install, I went to fire it up and check everything and noticed the radiator was squirting out a little fluid...

So I got hooked up with a new radiator from MainStreamPerformance.com and installed it.

I adjusted the clutch throw (by adjusting the cable) and nearly had a heart attack when it wouldn't go into any gear..... luckily I just needed to adjust the cable a little tighter. *whew*

Well I drove it 60 miles that evening... in lower rpms the drop between shifts is only 500 rpm's.

I cruised home at 70mph (5150rpm).

I'd say it's not *that* agressive.....

[Black R]

i'll try to go back and put up the final pics as well as all the thanks to Craig (AssPenny) for the picture hosting through http://www.we-todd-did-racing.com, Galaxy Machine for the machining of the gear, Len @ Baranco, Mike and Charles @ http://www.mainstreamperformance.com, Ben (IN VTEC) for his support and help, and of course Willard and everyone else here who contributed.

I've had a chance to daily drive the car for a while and rip on it down the hwy with some friends, street tune it a bit, autox an event, and even take the motor to ~10k...! It's safe to say that it's working well!

I'll refine and get a final version up with torque specs in a bit. :thumbup: and thanks again!