I've got an 88 Civic AWD and I'd love to be able to use a bseries motor instead of the dseries. My question is, if I could source an AWD CRV tranny would I be able to keep the wagon AWD drivetrain? I'm sure the driveshaft would have to be adapted a little bit but mechanically would it all work?

 

I'd be really interested in seeing what it takes to bolt the tranny into the Wagovan as well. I have a B20 in my 90 Wagovan, and I'm looking at pretty much the same thing as you are. I already have the CRV tranny, and all I need to do now is find the time to see what it would take for it to bolt in.

You are right that the driveshaft would have to be modded slightly, as the flanges are supposedly slightly different. Chances are the length will be off slightly as well. The gear ratios are mildly different also, but its a miniscule difference.

Have a look at this thread for some info on a similar setup (Del Sol). He starts looking at putting the Wagovan rear diff into the car in the last couple pages.

https://honda-tech.com/zerothread?id=1708933

 

I didn't do the math but rallysol, the person that started the thread above said that the crv and the wagovan is off by .004. If you are going to keep the viscous coupler, it would not be enough of a difference to have exsesive wear.

 

So the only small issue is the gear ratios being slightly different? And the only problem would be that it wears slightly on the viscious coupling? How so? I guess you could do a solid axle but wouldn't that short the life of the drivetrain as a whole since it'd receive more shock?

 

It would wear the viscous coupler and if the coupler was eliminated I would imagine that it would shorten the life of the drivetrain and excessively wear the tires. I think I remember reading that after a mile the front tires would have traveled 20 less feet than the front. It does not sound like much but if you have ever had to push a car with a spool you will realize that even going around a slight curve creates binding.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ickyhonda &raquo;</TD></TR><TR><TD CLASS="quote">I think I remember reading that after a mile the front tires would have traveled 20 less feet than the front. </TD></TR></TABLE>

I'll check the numbers when I get home (OEM rear diff ratios) but based on my memory of the diff ratio in the Wagovan diff, and if the difference really is only .004, then that puts the difference right around 8 feet over 1 mile (5280'), and that's about .15% or less than one percent.

I'm home now, and looked at the real numbers:

Wagovan rear diff ratio 2.529
CRV rear diff ratio 2.533

Difference is .16% or roughly 1/6th of one percent. That is an insignificant difference in my opinion.





Modified by Jaker at 3:08 PM 4/18/2008

 

Freakin rock on, I'm doing it then!!! Going to keep the viscous coupling though

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jaker &raquo;</TD></TR><TR><TD CLASS="quote">

I'll check the numbers when I get home (OEM rear diff ratios) but based on my memory of the diff ratio in the Wagovan diff, and if the difference really is only .004, then that puts the difference right around 8 feet over 1 mile (5280'), and that's about .15% or less than one percent.

I'm home now, and looked at the real numbers:

Wagovan rear diff ratio 2.529
CRV rear diff ratio 2.533

Difference is .16% or roughly 1/6th of one percent. That is an insignificant difference in my opinion.
Modified by Jaker at 3:08 PM 4/18/2008</TD></TR></TABLE>


How often do you only drive one mile?

Not trying to start **** but the CRV & wagon rear ends aren't that easy to find. Though I am interested in the prospect of using the wagon rear end with my CRV tranny. Also I do suppose the difference could be eliminated completely with different tire sizes



Modified by d357r0y at 9:00 AM 4/23/2008

 

Hey guys,

This should work without issue. Keep your stock driveline and only modify the first length of the propeller shaft. If the flanges on the transmission outputs can't be swapped, all you would need is a flange from a CRV propeller shaft. Give the CRV flange, your front propeller shaft and a length measurement to a drive line shop and you're golden.

 

I'm feeling really risky, anybody know the compatibility if I wanted to use a k-series based CRV AWD tranny?

 

Find someone with a FSM and tell the rest of us what you learn

 

I'll see what I can find out of sheer curiosity but I think I'm going to stick with Bseries after weighing the pros/cons of both.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by QuarterMileMaster &raquo;</TD></TR><TR><TD CLASS="quote"> k-series based CRV AWD tranny?</TD></TR></TABLE>

I've thought of that as well, but I considered doing it as a 6spd AWD with the matching rear end...

Heres some info if you haven't already seen it.
http://mysite.verizon.net/resqxfi7/acura5150/
http://www.elementownersclub.c...25635

 

How would you do that? Where is there a 6spd awd tranny?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by QuarterMileMaster &raquo;</TD></TR><TR><TD CLASS="quote">How would you do that? Where is there a 6spd awd tranny?</TD></TR></TABLE>

You take the 6th gear out of the 6spd FWD trans and put it in the AWD trans

http://www.elementownersclub.c...25635

^^ That link has info on how to do it...

 

Ok, now that is freakin killer!

I'm about 1/2 inch away from going K-series after all...

 

History - The CR-V is not the first Honda to use the moniker Real Time 4 Wheel Drive (RT4WD) to describe it's AWD system. From 1987 through 1991, Honda offered a Civic Wagon with RT4WD. However, that car used a slightly different system. The RT4WD in the Civic functioned in a similar manner, but it used a viscous coupling to mate the engine to the rear wheels. The newer design in the CR-V uses a multi-plate clutch pack to accomplish the same goal.

RT4WD Operation - I'll try to answer quite a few common questions in this first section. Bear with me as I ramble a bit.

The AWD system in the CR-V is probably best described as an automatically engaging four wheel drive system. For the most part, it routes power from the front to the back whenever a wheel loses traction. There is no side to side distribution of power. As soon as traction is restored, the system disengages and the vehicle returns to a purely FWD mode. The amount of time it takes to engage is minimal. I've watched it on slow-motion video and in the real world. It takes little more than a quarter turn of the tire for RT4WD to engage the rear wheels. The more slippage you have, the more power it sends to the other wheels. RT4WD will work when driving in reverse. There is no indicator light to show when the rear wheels have been engaged. There is no way to lock the system as with Honda's other AWD system, VTM-4. If you were to force RT4WD to work all the time you'd break it or damage the entire drivetrain. The AWD CR-V may be towed "flat" as might be done behind a motor home. See the owner's manual for instructions. RT4WD will disengage when the brakes are applied. This allows the ABS to brake the front and rear wheels at different speeds as is sometimes necessary.

Technical Description - The RT4WD system is comprised of five basic components. There is a transfer case attached to the transmission, a propeller shaft running from the front to the rear, a dual pump and clutch system at the end of that shaft, a rear differential between the rear wheels, and two half-shafts which direct power to the rear wheels.

Little is known about the transfer case up in the front of the CR-V. Most of Honda's documentation focuses on the pump system built into the rear differential. What we do know is that it allows power to be routed from the transmission to the rear wheels through the propeller shaft. Think of it as the first step on the road to powering the rear wheels.

The second step is the propeller shaft that stretches from the transfer case to the rear differential. This propeller shaft is constantly spinning. It never stops. Well... unless you put the car in park and shut it off. Even though the shaft is constantly spinning, it does not send power anywhere. The connection at the transfer case spins the propeller shaft, but the propeller shaft isn't turning anything at the other end. Simply put, the shaft isn't long enough to reach the rear differential without help.

Step three for this distribution of power is where things get interesting. The pump and clutch system ahead of the rear differential makes the decision as to whether or not the differential deserves to get any of the power that the prop shaft is constantly offering. I wrote above that the propeller shaft isn't long enough to reach the rear differential. Well, the pump system allows the shaft to "grow" just enough to reach and make the connection. Here's how the pumps make the decision to send power, and how the clutches make the necessary connection.

The differential housing contains two hydraulic pumps and two wet clutch packs. Both are positioned just ahead of the differential. The propeller shaft powers one of the hydraulic fluid pumps. The rear wheels power the other hydraulic pump via the half-shafts and differential. Both pumps are responsible for circulating hydraulic fluid between one another. As one pump pushes, the other pulls. It's sort of a ying and yang thing. By the way, this is the same fluid that needs to be changed every now and then (see the earlier article). When the propeller shaft and the rear wheels are spinning at the same rate, the pumps are pumping at the same rate. Under those conditions, the pressure of the fluid is stable. If either the prop shaft or the rear wheels start spinning at a different rate, the fluid builds pressure within the pump system. This pressure pushes open a valve in the system and fees that pressure to the two multi-plate, wet clutch packs. This pushes to the two clutch packs together and they form a handshake between propeller shaft and the rear differential. The propeller shaft has "grown" long enough to reach the differential.

All our ducks are lined up, so let's recap for a second. Now we have power running from the transmission, through the transfer case, and along the propeller shaft. The propeller shaft is now linked to the rear differential via the connection made by the two clutch packs.

So what does the differential do? The differential is step four. It routes the power down each of the half-shafts to the rear wheels. It's a big Y joint. Normally, the differential is just spinning freely. It is powered only by the rear wheels, which are, in effect, being dragged by the front of the vehicle. When the clutch packs connect, the engine becomes the source of power. Now the engine is driving both the front wheels and the rear wheels, through this long series of mechanical connections. Welcome to four wheel drive.

All this happens very quickly. As I wrote above, the connection and power distribution process can be completed in the time it takes for a wheel to make one quarter rotation. The system also disengages just as fast. As soon as the clutch packs make their connection, the propeller shaft and rear differential start working in unison. That restores equality between the two pumps, which means no more pressure, which means nothing to keep the clutch packs engaged and they disconnect

 

Stuck my head under a K series Element today and it appears to have the same rear differential as the B series CRVs. Unfortunately the clerk behind the counter in Parts and Service wouldn't let me lay a finger on their service manual. Anyone else have any luck finding the K's rear diff ratio?

 

Eh, I've given up on the idea and I'm selling my wagon... It just seems like it's going to be a ticking time bomb no matter what tranny/diff I use...

Gonna stick with trusty ol' FWD...

 

!!! Where's your sense of adventure?! C'mon man, you know you want it. If you're not making much torque and all your HP comes in high in the RPM band you should be in good shape regardless of which series you choose.

 

If your not breaking stuff you're not fast enough! Keep it and stop being a Sally.

 

Alright, back in the game, no more "sally"

Does anybody know what kind of gearing the bseries awd tranny has? Like longer or shorter? Or if it'd be interchangeable with the LS trans for highway cruising?

I'm trying to decide on bseries or kseries and my main reason to go kseries is the 6th gear option because I hate cruising on the hwy at 4k+ rpms...

 

Update:

ok, so assuming I read everything right, this seems to be what the gears would be like with the kswap 6speed conversion:
http://www.fatboyraceworks.com...are=0

I haven't been able to find the gear ratios for the bseries awd tranny yet

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by QuarterMileMaster &raquo;</TD></TR><TR><TD CLASS="quote">I haven't been able to find the gear ratios for the bseries awd tranny yet</TD></TR></TABLE>

here's a little info

1st: 3.500
2nd: 1.956
3rd: 1.344
4th: 1.071
5th: 0.812
Reverse: 3.000
Final: 4.562

K AWD vs. B AWD trans... http://www.fatboyraceworks.com...are=1

B AWD transmission vs. GSR http://www.fatboyraceworks.com...are=1

B AWD vs. USDM ITR http://www.fatboyraceworks.com...are=1

 

Rock on!! Thanks!

It looks like you get about another 20mph or so with the 6th gear (although I doubt I'd ever be going 170+mph). I wonder if there's a way to translate that info in to speed to rpm ratios...

I'm really starting to lean towards Kseries regardless though...

Does anybody know if the gearing is interchangeable in the bseries awd tranny with other bseries gears?