B Series Transmission Info

[b-eater]

I got this from the net ... to share and to discuss.

Integra LS (b18b)
1st - 3.250
2nd - 1.900
3rd - 1.269
4th - 0.966
5th - 0.714
final - 4.266

Integra GSR (b18c1)
1st - 3.250
2nd - 1.900
3rd - 1.360
4th - 1.034
5th - 0.787
final - 4.400

Del Sol VTEC, 99-00 Civic Si, and other various JDM cars with b16's (b16a3, b16a2, b16a, b16b, b18c5, b18c spec R) All hydro b16s came with these ratios
Also, USDM ITRs and pre 98 JDM ITRs
1st - 3.250
2nd - 2.105
3rd - 1.458
4th - 1.107
5th - 0.848
final - 4.400

JDM ITR, 98+
1st - 3.250
2nd - 2.105
3rd - 1.458
4th - 1.034
5th - 0.787
final - 4.785

Now that you know the ratios of the available transmissions, lets start off by examing the ratios. The Integra LS has tallest final drive of 4.266 along with gears that are furthest apart. This is due to the relatively flatter torque curve of the lower-revving b18b.

The GSR tranny like the LS tranny, uses the same mainshaft (1st and 2nd gears), However it uses a 4.4 final drive, with shorter, closer-ratio 3rd, 4th, and 5th gears. Although it utilizes the same final drive as the b16, it's gears are spaced further apart due to the greater torque and less "peaky" characteristics.

Then there's the b16/USDM ITR transmission. Aside from the ITR having a LSD, these transmissions are identical ratio wise. These use the 4.4 final drive ratio, along with a unique 2nd gear. Because of the peaky powerband of the b16, they have the shortest, and closest-ratio gears of all the b-series transmissions. Yes, with 205/50/15s the highway RPMs are near 4400 at 80mph, however do to the very short stroke of the b16, this is not a problem.

And last but certainly not least is the 98+ JDM ITR transmission. This transmission is honda's hybrid transmission for their OEM FWD "track car." It uses an exclusively higher final drive ratio of 4.785 along with b16 1st, 2nd, 3rd gears. It then uses GSR 4th and 5th. It is obvious that they used the 4.785 final drive because it yielded better acceleration, however this usually decreases the theoretical top speed (and increases cruising rpms) This is why I am sure that they decided to go with the gsr 4th and 5th. Why not b16 4th and gsr 5th? Because the 3rd -> 4th RPM drop on b16 trannys is already really good, so it would be better to make the gap further here than it would be between 4th and 5th. Plus most people would rather have a longer 4th gear to prevent having to shift into 5th.

Take note, Final drives effect the mph/kmph between the gears, where as gear ratios effect the rpms between the gear. This means that the rpm drop from 2nd -> 3rd will always be the same from 8000rpm. This also means that installing a JDM ITR final drive, on your stock gsr transmission, you will NOT have a closer-ratio transmission.

For people that do lots of distance driving, you may consider getting an LS 5th gear. It will lower the cruising 5th gear RPMs as well as lower the engine noise. To do this you will need the mainshaft and countershaft 5th gear from an LS. As far as I know, cable 5th gears will not work.

 

[shiroitenshi]

Good info.. thumbs up for contributing..!

 

[hattech-v]

good info.

 

[avantasia]

wats the close ratio for kaaz? 3, 4, 5?

 

[hattech-v]

3 - 1.6520
4 - 1.3080
5 - 1.0330

 

[evoX2]

i am confuss with gear ratio. If compare B18C & B16A:

B18C
1st - 3.250
2nd - 1.900
3rd - 1.360
4th - 1.034
5th - 0.787
final - 4.400

B16A
1st - 3.250
2nd - 2.105
3rd - 1.458
4th - 1.107
5th - 0.848
final - 4.400

In 2nd gear which one have higher RPM?

Final Drive effect the overall RPM, how about the 1st, 2nd, 3rd...ratio? How it works with the FD?

 

[b-eater]

Now that I have covered the contents of the various honda b-series transmissions, I am now going to cover a few mathematical/physics formulas that I have found useful. Along with covering the common fallacies.

Gears do nothing but torque multiplication between the engine and the wheels. At any given time, you're using two gears to drive the car, say you're in 5th gear of 0.848 on a b16 transmission with a 4.400 axle ratio. Multipy that gear ratio by the axle ratio and you get the complete gear ratio of that gear.

0.848 * 4.400 = 3.7312

Now that is your actual gear ratio in 5th gear. That means that for every 3.7312 engine revolutions, your wheel makes one full rotation. Another thing that you may find interesting, I have been doing a lot of researching on BMW's as I plan on buying some e36 this year. After looking at the ratios I noticed that the numbers were different. Some of them use a 1.0 5th gear ratio, along with a 3.73 axle ratio, now obviously 1 times 3.73 is well, 3.73. So that means that paticular BMW's 5th gearing is nearly identical to honda's b16 gearing. This results in confusion when discussing the axle ratio modification you've run. "You're running what? A 4.785? Holy shit that's crazy!!" But in reality a 4.785 compared to a gsr 0.747 5th gear is like a 3.76 axle ratio on a BMW. Not to mention that tire diameter also effects this. Moving on...

 

[b-eater]

Now before anything else is said, it is essential for you to understand what horsepower really is and where it comes from.
Horsepower is nothing but the measurement of torque and RPM. Here's the formula for horsepower

HP = (torque) * (RPM) / (5252)

With that said, lets think about a domestic v8. Yeah, they have lots of torque, but most of them can't rev over 6000. For demonstration purposes lets see how much 200ft/lbs at 4000rpm really is.

HP = (200) * (4000) / (5252)

HP = 152.32

Now 100 ft lbs at 8000 rpm.

HP = (100) * (8000) / (5252)

HP = 152.32

Notice that these HP numbers are the exact same. Naturally, the motor that only makes 100tq is going to significantly smaller in displacement. (probably about 1/2 the size) But All one would have to do is double the gear ratio and you would never know the difference! Honda makes it's power by using smaller high-revving motors. Because the redline is so high, the gearing is also numerically high and the gears are short. The b16 gears may end at the same mph as a 6000rpm redline VW for example, but if you were to give the 8000rpm honda those same ratios and wheel dimater those gears would be "tall" So many people look at the specs of hondas b16 and they see 113ft/lbs and 1.6 liters, and they complain it doesn't have any torque! This isn't really a valid argument, mainly because these people have no concept of how gearing and torque multiplication works. Yes the b16 may have a low number of torque, but where it doesn't have torque, it has gears that are designed to keep the RPMs higher. This gives the impression of "this motor sucks so much that I have to rev the piss out of it to move" But in reality it has completely different characteristics of your typical domestic v8. I guarantee you that if you put a b16 in your civic along with a b16 transmission, and that if you were to change the 8 on your tach to a 6 and the 4 to a 3, as to trick you of how fast the motor was revolving, every oblivious person would ride in your car and think that you had an h23 "torque monster" in your car.

With that said, I want to show you this image that I have created with MathGV for windows.


In this graph, I have two lines plotted.
The red line is Y = 130. This is the theoretical torque line on a dyno plot. Again, for demonstration purposes.
The blue line is Y = (130) * (X) / (5252) This is the horsepower formula with 130ft lbs of torque.
As you can see, there is more torque than horsepower up until after 5000. Because of the formula for horsepower, no matter what you're going to have the exact same amount of torque as horsepower at 5252rpm. Because of this, if your motor's redline is 5000rpms. There is no way that you will ever have more hp than torque unless you make power beyond 5252rpms. This also means that if you continue to make power (torque) beyond 5252RPM, that no matter what, you will have more horsepower than torque. This is concrete physical mathematical proof of this. No matter what this will never change. Bottom line, if you want horsepower, you need torque and high RPMS to get it. If you want to have more torque than horsepower, you can either stop making power beyond 5252 rpms, or you can let off the gas, or get a motor that doesn't rev beyond 5252rpm. If you want a lot more horsepower than torque, you better start reving beyond 5252 rpms.

Hopefully after analyzing this graph and reading what I've said, you now understand the value of keeping those RPMs up with your honda motor. The closer you can stay to redline, the faster your car will be. This is the value of close ratio gears. What I am about to share with you is something that dawned onto my crazy ADHD self when I was watching "The Bourne Identity" one night. I have never seen this on any of the transmission pages. It seems so simple, but it is something that I have never seen anywhere. I can only hope that it's something that will be covered in one of my future mechanical engineering classes. I don't know. For the longest time I was calculating the RPM drops of various transmissions. b16, gsr, ls, bmw e36, GM's t-56 (ls1 6speed), etc. But to do that I had to manually do the formulas. Find the mph of X gear ratio with Y axle ratio and Z wheel diameter at 6000rpm and compare it to all the other gears and blah blah blah. It is very time consuming and it sucks. I wished that there was a way to find out the RPM drops without having to do all that. But then I got it and man was I very very very excited. Check this out.

B16 transmission for example
1st - 3.250
2nd - 2.105
3rd - 1.458
4th - 1.107
5th - 0.848
final - 4.400

to simply calculate RPM drops:
gear ratio of the next gear / current gear ratio = rpm drop

2nd gear / 1st gear = 1st -> 2nd RPM DROP %
3rd gear / 2nd gear = 2nd -> 3rd RPM DROP %
etc.

2.105 / 3.250 = 0.64769 or 64.769%
1.458 / 2.105 = 0.69264 or 69.264%
1.107 / 1.458 = 0.75926 or 75.926%
0.848 / 1.107 = 0.76603 or 76.603%

So I take my b16 up to 8000rpms and then shift into 2nd. 8000 * 0.64769 = 5181.52

after shifting from ___ RPMs drop to ____
1st -> 2nd = 5181.52 rpm
2nd -> 3rd = 5541.12 rpm
3rd -> 4th = 6074.08 rpm
4th -> 5th = 6128.24 rpm


Because of these ratios and the relation they have to each other (RPM Drops) Unless you're making LOTS of power (over 250whp) you want to use these ratios you're trying to optimize your quarter mile times. The reason is that they are the closest together RPM wise. Yeah, you may be making 500whp on your turbo civic, but you may not hit 500whp until you're at the very end of RPM range. This comes out to "........500WHPyeahhhhhh....shift................. ..500WHPwoohoo!!!" Like I said earlier, you have 3 OEM final drives to choose from, 4.266, 4.400, and 4.785.

If you have a high hp turbo honda, you (like most people) have traction issues. This is because you don't have enough traction. In the quest of acquiring more you have ONLY two options.
1. put less torque to your tires
2. get better tires.
There are different ways to put less power to the wheels. You can either lower your boost level, or use gearing to reduce your torque. If you use the ls transmission your gears are going to be further apart and your RPM drops are going to be greater. This is going to hurt your acceleration Inheritently this is an issue that many people are trying to overcome, because of this, I have hypothesized and come up with a great hybrid theory (loads linkin park playlist in winamp).

1st = 3.23
2nd = 1.9
3rd = 1.458
4th = 1.107
5th = whatever you want (:

utilizing the gsr/ls 1st and 2nd gear along with b16 3rd and 4th gears. The reason being, 1st gear is the same no matter what, so there's no choice, the taller 2nd gear because traction is usually such an issue in 2nd gear that you might as well have it carry you further into 3rd anyways. b16 3rd and 4th gear ratios, and whatever 5th. This results in the closest OEM 2nd/3rd/4th gear ratios. (lowest rpm drops) Most people try to avoid shifting into 5th anyways, so if you'd like, you can use a taller LS or GSR 5th gear. it's up to you.

In typing this page, I am covering mostly the theory to show YOU what I have learned and attempt to explain what's really going on. At this point I just don't feel like pluggin all the numbers in for you. If you want to run 25" slicks with a 4.4 final drive and you want to know what mph you'll be at when you redline at 8000 rpms, well put it in the formula.

MPH = (RPM)(TIRE DIAMETER in inches) / (GEAR RATIO)(FINAL DRIVE) (336)

 

[evoX2]

thanks for the info, now i can understand more....btw, where's the source?

 

[b-eater]

i copy from http://honda-tech.com

 

[hanjin]

I know which transmission i want to get. Probably the 16A one... But anyone got stock? I am current driving an EG6 Auto and need to convert to manual.

Thanks

 

[hattech-v]

i got the auto to manual package. mean the conversion. pm me for details