OEM B series trannies fall in the following order from shortest to tallest gearing:

1) 98-01 JDM ITR/CTR. Factory LSD and 4.78 final drive.
2) 96-98 JDM ITR / 98-01 USDM ITR. Factory LSD and 4.4 final drive
3) B16 tranny has same gearing as USDM ITR tranny, but without a factory LSD. Some JDM units had factory LSD.
4) Integra GSR tranny has taller gears and 4.4 final drive with no factory LSD. Some JDM units had factory LSD.
5) The Integra LS tranny has the tallest gears with 4.266 final drive and no factory LSD.

I have a Type R tranny with an LS 5th gear and 4.266 final drive ratio. I did it because I'm not a hardcore racer. My car is a daily driven street/show car. If I was a hardcore racer, then I would have left it alone. Here's the how and the why.

After I first started to drive the car with the OEM Type R tranny, I immediately realized HOW short the gearing was. My RPM's at 70MPH was 4,000 and my RPM's at 80MPH was 4700 RPM's. This is great for racing and good acceleration, but sucks for fuel economy and engine longevity. With no luck, I looked long and hard for a GSR or LS tranny with a GOOD LSD installed........meaning a Quaife or factory LSD. No OBX or Phantom Grip pieces of ****. With any used tranny, you always run the risk of getting a **** sandwich. So I just went full bore and sprung for tranny surgery courtesy of Gearspeed Transmissions in Rancho Cucamonga, CA. The point of contact there is James Ornelas. I pulled the Type R tranny and delivered it there along with a brand new Quaife LSD.

They rebuilt the entire tranny with new carbon synchros, an LS countershaft, an LS 5th gear, and an LS 4.266 final drive. 1st through 4th gear remained the same. I had to use the Quaife LSD because the ITR or CTR factory LSD will not work with the smaller ring gear. The total bill from Gearspeed was $1500. The Quaife ran me $930 shipped.

After I re-installed the tranny, I was VERY pleased with the performance. 1st through 4th acceleration suffered little, and 5th gear is NICE AND LOW. 3100 RPM at 70MPH and 3600 RPM at 80MPH.

Remember that the gearing is the same between an ITR and a Civic Si B16 tranny. Only difference is LSD versus non-LSD. So if you HAD to rebuild one of these short geared trannies, that is your golden opportunity to add LS 5th gear, final drive, and LSD. 1st through 4th are about the same as GSR tranny acceleration.

If you did the same thing with a GSR tranny, your 5th gear would be the same as mine but acceleration in 1st through 4th will be worse because the GSR longer gears.

 

Wow, you paid a damn pretty penny for that install!

A brand new OEM Type R tranny w/ LSD is Like, $1600? I think.

If you do a lot of Highway Driving, it sounds like it MIGHT be worth it, but then again. if your doing a lot of highway driving, maybe you should get a daily beater and keep the R in the garage? It sounds like you can afford it.

Just my $.02

 

Considering that I did a full Overhaulin style build on my Civic exceeding $25K, the tranny money was a drop in the bucket.

I'm not advocating that everyone goes out and does a rebuild just to get the RPM's lower. All I'm saying is that if you HAVE to rebuild an ITR tranny or a B16 tranny, then this is one route you can go.

P.S. I have the car posted on My Space.

http://www.myspace.com/fukengrooven

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Toy Civic &raquo;</TD></TR><TR><TD CLASS="quote">... 5th gear is NICE AND LOW. 3100 RPM at 70MPH and 3600 RPM at 80MPH.
</TD></TR></TABLE>
Yep, sounds about right The LS 5th is a great cruising gear.

 

Good information in this post, however:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Toy Civic &raquo;</TD></TR><TR><TD CLASS="quote">... sucks for fuel economy ....</TD></TR></TABLE>

I searched but I can't find the thread, there was a multi page discussion regarding this topic. Having a higher final drive does not always give you worse gas mileage. It's all about the fuel map. Look at the axis where the throttle position percentage meets the RPM. In most rows, the higher final drive will use up less gas. Simply because less throttle is applied, EVEN though it is at a higher RPM. Then there is also the argument of not needing to give it as much gas to reach your cruising speed. Only downside is the higher RPMs your engine will see resulting in more stress, but there is always a con to everything, and I accept this one.

Another import thing to note. The JDM ITR 98+ Spec transmissions do indeed have the 4.785 final drive, but their 4th and 5th gears are GSR gears. Roughly translating to having a 4.4 FD on the 4th and 5th gears. While the pre 98 spec JDM ITR transmissions are basically identical to USDM ITR transmissions. So obviously putting in a JDM 4.785 final drive in an USDM ITR transmission will yield you with a more aggressive 4th and 5th gears compared to the JDM 98+ ITR transmissions.

I considered using an LS 5th gear, but a lot of people simply state how much taller the LS 5th gear is compared to the ITR/B16 gear and that it will simply fall flat on its face when accelerating. I'm quite happy with the rebuild that I did consisting of my USDM ITR tranny with carbon coated syncros and the JDM 4.785 FD. Only thing that would make me happier is an ATS 4.92 FD But it sucks for highway cruising, which is why I did not sacrifice daily driveability for performance and got a daily beater instead.




Modified by neo_ at 2:36 AM 1/14/2007

 

I can see using the LS 5th gear for highway cruising, but I don't think I'd go so far as installing the 4.26 FD. My car cruises at 3,900 rpm at 80 mph with the LS 5th and a 4.4 FD (stock size tires). Coincidentally, my car gets the best gas mileage right about there, and it's nice to still have some throttle response in 5th for passing.

Also, the B16/B18B ring gears are smaller in diameter than the B18C ring gears. This makes the diff smaller too. Probably not a big deal, as Quaifes are tough and stock B16 trannys have been used in high-output applications, but still.

Oh, and you forgot about the B17A transmission. Same as the JDM B16A, except it had the shortest 1st gear, a 3.3-something. Only tranny to use it.

 

Hey bro I have a jdm itr 96 spec tranny HMO 1st sold this to the guy I bought my swap from with KAZZ lsd in it but the Kazz broke they warrantied it for him as a 1 time curtosey deal being that he was a ruturning customer, I know kaaz isnt what they put back in it, because the kaaz speedsensor gear still remained in the tranny it took me a while to figure out why my speedometer & vtec wouldnt engauge cause the Kazz gear was to small & wouldnt catch the groves. Im contemplating tearing this tranny down & doing a gsr 4th & ls 5th but dont know exactly what parts to get and or if my lsd is cusco or what type of lsd it is exactly, I dont want to order oem usdm honda gears to find out they wont work in my jdm tranny Im sure it is a clutch disc type lsd due to the chatter it made without friction modifier I dont want to spend more than $600 rebuilding this thing, every once in a while when im beating on it ill get the typical 3rd gear grind, but I need to replace the tranny case anyways the 1/2 check plug threads are hammerd & want yhe LS 5th gear anyways so might as well do carbon syncros while im in there, do u think the gsr 4th would be a waste of $ thx Idan

 

Actually this is false. The B16/B18c1/5 all use a 4.40 final drive ring gear (USDM). They are all the same and all swap over to each diff.

An LS diff is the same exact thing as a B16 diff. The LS diff uses a taller ring gear (Less teeth)

The only diff that is unique in the GSR diff as it uses tapered needle bearings as opposed to the sealed ball bearings that the LS/B16/B18c5 trannys use.

To use a GSR diff in any of the other B-series cases you would need to pull the bearing seats out of the GSR case and install them into the new case.

The diff sizes do not change (LSD or Non-LSD), only the ring gear that is bolted to them.

 

WRONG....the rings gears DO NOT swap from b16 to a b18c/c5!!!!

a b16 ring gear WILL NOT WORK ON A c5 LSD diff!!!

you can use SEALED bearings on a GSR diff!!


gsr=itr are the same 4.4 sized ring gear....ls and b16 use a smaller center on the diff!

 

I DD my R and know exactly where you are coming from, I plan to buy a new DD soon.

 

Around '98 the usdm gsr transmissions started getting the ball bearing diff bearings. Typically 94-96, and maybe 97 gsr's got roller bearings.

Correct, the b16 and LS share the same diff, but do not share the same ring gear. b16 =66t and LS=64t.

The gsr and itr share the same ring gear. 66 teeth

BTW... my boosted lsv has a b17 1-4 and LS 5th in a hydro case and the 3800rpm @ 80mph is great on the highway, but does fall on its face when shifting to 5th in the 1/4mile.

 

Holy crap, you went the complete opposite way I did:

I wanted to go crazy with my itr tranny because it wasn't agressive enough for me so I did ats 4.9 final drive AND ats close gearset AND ats LSD.

75mph at 5500 rpm in 5th gear crazy. And I still get over 35 mpg on the highway! haha

 

Wow...how is acceleration on that thing? I thought my ITR with a 4.7 FD was pretty short geared. I dont think ill ever put an exhaust on it cuz of the high RPM drone.

 

When I owned a 2000 Si I installed a USDM ITR LSD diff and used my factory B16 4.40 ring gear. Get your facts straight before you tell me I am wrong. I have personally done it with no problems what so ever. Thanks for trying though.

 

^ win. I can't wait for this.

 

It looks like fun until you are about 5 hours into a road trip and you can't get that buzzing sound out of your ears. It would probably help if I had AC and could roll my windows up too .

 

I'm just doing the 4.7 immediately after expo with the normal gearset so it won't be THAT severe.

sir, you need AC

 

NO YOU HAVEN"T!!!

a factory b16 ring gear WILL NOT FIT ON AN ITR DIFF!!!

you might have had the ITR RING GEAR ON THE ITR LSD DIFF BUT THERE IS NO WAY YOU PUT A FACTORY B16 RING GEAR ON AN ITR DIFF!!!!

NOT POSSIBLE!!!

you need me to take pics to prove it? I have 5 of them in my garage right now.....

 

Yeah, 4.7 is what I have as well. I am one of the few that would go back to a 4.4 with no regrets. I seem to run out of gear at the darndest places at the track and I really see a need for a 10k redline now.

For 2 months out of the year, I do. Somebody needs to make an AC "quick connect/release" kit. I'd be in on that.

 

Why don't you just put it back in? What do you think you're really saving by not having it? I assume weight since you can just take the belt off?

 

Here's a couple of b and k-series transmission comparison's.

 

Yeah, just weight. Whre I live I only need it for 2 months out of the year so I feel it would be pointless the rest of the year. Not too mention it really freed up alot of engine bay space that I don't have to work around anymore.

 

I admit it has been about 6 years since I owned that car, but I thought for sure I swapped the factory Si ring gear over. I specifically rememebr thats how I learned that the bolts that attach the gear to the diff are reverse thread.... I do not know what year ITR the lsd diff came out of because I got it off ebay. But I am 90% sure I swapped the ring gear over to it. I am wondering if I wasn't sold a JDM B16 diff and told ot was an ITR. Would those be different sizes?

 

I have the ATS Final over here with the stock gearset. It is kind of odd cruising at 4500-5000 on the freeway, but at least I can pass people in 5th. The fuel economy is the same, so not sure why you spent money to change the gear. It's the tune that will effect the gas mileage and if you have a good tuner it should be the same as stock fuel economy if not better since the stock map runs rich.

 

Talk about V-tec on the highway...this would suck if your vtec was set at 5,500 rpm but if it works and make a difference. im diggin IT