1) What's the difference between the ITR and Si fifth gears?

According to Acura for the ITR:

23461-P80-F00 GEAR, COUNTERSHAFT FIFTH
23581-P80-F00 GEAR, MAINSHAFT FIFTH

According to Honda for the Si:

23461-P21-F00 GEAR, COUNTERSHAFT FIFTH
23581-P21-F00 GEAR, MAINSHAFT FIFTH

However, according to most online sites, the ratio is 0.848 for both - so what's the difference?

2) Can you mix and match B-series clutches / flywheels? I want to use an ITR flywheel with an OEM Si clutch. Are the sizes or anything going to make a difference?

 

Please make your thread titles subject specific. Edited.

 

thanks.

 

according to the service manual, the 5th for the si is 0.875 while the itr is 0.848.

Also while searching, I found the del sol vtec has a 3.307 first gear, it is possible that works in an si / itr trans?

 

All b-series hydro clutches and flywheels are interchangeable with all hydro b-series. I would believe the gears are interchangeable as well. I have a ls 5th gear in my b16 s4c transmission. Why do you want the shorter itr 5th gear? If the b16a s4c 5th wasnt short enough as it is.

 

I have a GSR fifth (0.787) with a 4.785 final drive. I want to go back to ITR (0.848) to get a little more out of fifth gear.

 

Damn that 4.7 is shorrrt, i'd ditch that for a 4.4 setup and call it a day. you could get a few hundred for your setup too so the 4.4 would be easy to come by. I have a usdm ITR tranny w/ the 4.4 in my DD ls/vtec coupe and can't imagine having the 4.7 to deal with all the time. I just picked up a 4.7 set myself but it's going to my CRX since it's just a weekend car for the track mostly

 

Yeah it is quite short. In 4th gear @ 40mph I'm at 3,400 rpms. I'm in fifth gear around the street. I'm actually changing up the setup even more and going for close gear 3 / 4 / 5.

My question is, if the ratios are the same what the f is the reason for different part #'s for the ITR / Si fifth gears?

 

Same reason they make different part numbers for alot of their stuff, stupid politics about Acura and Honda name brands and it makes it easier to charge more for an Acura ITR gear than a Honda civic Si gear....stupid politics

 

Nah cause the prices are the same. As a matter of fact, both the 4th and 5th gear part #'s are different specifically for the ITR. The ITR 1 / 2 / 3 are exactly the same for the Si. I find it hard to believe that Acura / Honda went out of there way to make different part #'s for the ITR 4th / 5th gears just "because".

 

idk the exact reason I was just giving 1 example of maybe why, I'm sure there are 100's more

 

Yeah. I guess it doesn't really matter as long as I get the ratio I want. It's not like they used a different material just on the 4th and 5th gears (between ITR and Si gears). I'll just count the teeth when I get em to make sure.

I might as well order the ITR ones since it's the same price, then I can say it's TYPPPPEEE R!!!

 

Well there's 20hp extra right there and if you add the "Type R" sticker you'll net another 10!

 

actually after more research, there's a 0.875 fifth gear. According to my calculations it will net about 20 lbs of torque over the 0.848 with only a 100rpm increase. So I'll get those instead since I'm going to the trouble.

In case anyone finds this thread later, the part #'s for the 0.875 fifth are:

23581-P21-010 GEAR, MAINSHAFT FIFTH
23461-P21-010 GEAR, COUNTERSHAFT FIFTH

 

another interesting piece of information is that you can use the 3.307 first gear from the 94-97 Del Sol VTEC or 92-93 GSR which would make your gearing even shorter in first. Not exactly the way you'd want to go especially if you have traction issues as-is, but it is definitely worth noting.