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AWD Conversion ForumThis forum is to help with the recent advent of new AWD conversions. Got a question? Ask it here. Got an answer? Drop the knowledge here
Please put this on YouTube when it's done! I can't wait to see the finished product!
Oh you know I've got to put up the infamous "all four wheels spinning on the lift" video. Just had a dream the other night that I was in the Civic doing donuts like a tank in the snow. Which is odd because I'm like in Arizona...
Oh you know I've got to put up the infamous "all four wheels spinning on the lift" video. Just had a dream the other night that I was in the Civic doing donuts like a tank in the snow. Which is odd because I'm like in Arizona...
Ha! Four tires spinning on a lift would be a good intro! Maybe donuts on pavement, lol.
Alright, it's back in for good. Everything buttoned up in the front. Trans shifts through all of the gears nicely. No leaks, noises, or funky smells. I still do not have any rear wheels or suspension, so test driving it is not an option at this point. I am really curious to see if I will like the gearing and hard shifting. The shifter does feel pretty good, but also still sits a little high. I may be able to deal with it. Won't know for sure till I drive the damn thing.
Sorry about all of the same damn pictures, I was happy to have it back together. As you can see there wasn't any clearance issues with the down pipe and dump tube. It actually worked out great! I had to get a new 90 degree silicone hose for the turbo to reach the inlet of the intercooler. That was a little tricky as the new manifold moved the turbo downward and towards the block more. I think I got it though. It's kind of crazy how you really can't tell that there is an AWD transmission in there. The only thing that gives it away is the placement of the starter and that's if you happen to notice it. You really have to get in there and look around for the cables now that the intake piping, radiator hoses, and catch can hoses are in place. Now that the front is done, it's time to tackle the rear. I'll be opening up the rear diff and hacking away at it. Stay tuned!!
That looks really nice! Like you said you can't tell it's not a normal tranny unless you're really looking. Can't wait to see what you have in store for the rest of the car!
Started digging into the rear differential. I've done a bit of research on the workings of the RT4WD system in the CR-V. I do not fully understand it at this point, but I know enough for what I want to try to do and accomplish with it. My plan is to delete pretty much half of the system, so I guess I don't need to fully understand all of it's workings. I'm taking a page out of "draggbody" build and installing an air locker into the rear diff to actuate the piston. If you do not know how the CR-V RT4WD works, there is plenty of info out there about it. Basically it is an automatic transmission with internal pumps, springs, valves, *****, clutch discs, and so on. It is fully mechanical which makes it easy to manipulate. The idea is to remove the pumps completely and block off certain passages that will allow the air pump to act directly on the piston that pushes the clutch discs together and locks the rear diff with the driveline. Still with me?? The system can get a little confusing. Especially when looking at 1D pictures and then looking at the actual parts in 3D. Hopefully the schematics along with pics of the internals of the diff will help.
The CR-V rear diff in all of its glory.
The internals...
There are 3 plates that make up the pump housing. The top is the piston housing, the "middle" houses the actual pumping mechanisms, and the "bottom".
The clutch pack, which is removed here, sits on top of the piston housing.
The brass looking thing is the thermal switch. I will be deleting that and hopefully plumbing the airline into the opening.
Here the plates are separated with the "middle" plate on the left and the piston housing on the right. I plan on blocking the two holes that are right next to each other, removing the thermo switch, and plumbing the air into the existing hole for the thermo switch. That tiny hole by the thermo switch is where fluid enters the piston housing and pushes it.
The thermal switch in the piston housing.
On the top is the piston housing and the where the fluid would normally exit. On the bottom is the "middle" plate with the regulating orifice. That will have to be blocked as well.
Here is the piston housing mated to the "middle" plate. You can see the thermal switch poking through.
This is the regulating orifice on the "middle" plate for fluid entering the piston housing.
This is where the "middle" plate mates to the "bottom" plate.
A hydraulic fluid circuit diagram is provided below to try to show how I think I can get it to work. The green highlight will now be air instead of hydraulic fluid and the X marks are where I will either weld or cap the circuit. As you can sort of tell, I will no longer need about half of the RT4WD system by using air to activate the clutches. I will still run the hydraulic fluid for the engagement of the clutches and for cooling purposes, but that's it.
The next picture shows you the inside and outside of the entire diff to give you an idea of where everything is at. It's still hard to tell, but the clutch pack houses clutches that splined differently. Every other clutch disc is splined to the housing and the other discs are splined to the shaft for the pinion gear that drives the differential. When all clutches are forces together, it is a direct drive of the diff. With the air locker, the diff will be locked at all times through the clutches to the driveline. When the locker is off, there will be nothing to drive the rear wheels. So this once AWD system will now be a 4WD system as it will either be "on" or "off" and nothing in between.
Hope this helps to explain things a little. Next is to figure out exactly where to plump the air line into. My goal is going is to not have to mess with the casing of the rear diff at all. We'll see how that goes...
I like the idea of having the ability to toggle the 4WD system on and off. 2WD for cruising. 4WD for rippin'-and-a-tearin'.
Yup, that makes two of us. If I could have it my way though, I would like it react the way it was designed while having the ability to fully lock up for launches. Unfortunately, it won't work that way. I do think it will be pretty cool to pull up to the burnout box on the strip, roast the front tires, and then skate off the line in AWD. That should make some people scratch their heads.
Originally Posted by scottcraft
Do you think durability will be increased using the air to lock it versus the hydraulics?
Actually, I think the opposite. Not so much from using air rather than oil, but because I will be deleting the system keeps the shock from destroying itself. Once the air locker is turned on, the clutches are completely compressed, locking the transmission and driveline to the rear diff and wheels. It will be quite a shock to the system and I am still unsure it the rear diff will be able to handle the twisting forces from the torque. The engine put down 451 tq to the wheels on the last dyno pull. It's not a question of durability at this point, it's a question of if the rear diff will survive any launches...
Unfortunately, it won't work that way. I do think it will be pretty cool to pull up to the burnout box on the strip, roast the front tires, and then skate off the line in AWD. That should make some people scratch their heads.
That would be so fun! A FWD burnout followed by an AWD launch. People would be very confused and also very curious...
Got the push-to-lock fittings and airline that I will be using. Gutted the pumps and tapped the existing hole where the thermo switch was housed for the airline. There wasn't much material there to tap, so I didn't like that. Also, once I threaded in the 90 fitting the case for the diff would not completely close up. In other words, the fitting was in the way and that spot will not work. No worries, just got to do it the hard way and go in on the other side where the orifices are. So now I will be putting the air in where the fluid used to exit. The flow of the air doesn't matter though, as long as it pushes the piston to engage the clutches. I'll use an NPT threaded plug to block up the thermo switch hole.
Air into the pump housing through the thermo switch.
Didn't even tap it straight, sheesh!
Unfortunately, not going to work.
Trying to plumb in on the other side of the pump.
Looking at the schematic, you can see that it really doesn't matter where in the circuit I plumb in. There really is only two places that I can plumb into though, so if this doesn't work I will have to modify the casing on the diff. I really am trying to avoid that, one for ease of installation, and two if I end up cracking the case down the road, I can just replace it and not have to worry about modifying it again. When I put the pump housing in the diff, leave the clutch housing out, and put the diff casing on, I can see there is a little bit more room on the "orifice" side of the pump and the casing. Tried to eyeball it and do a mock up with a fitting I had. This actually took a bit of time as it would keep falling off when I put the case on. I will have to drill into the pump housing to plumb the fitting in, so I really only have one shot at it before the pump, and pretty much the whole diff, is garbage.
Mock up of new position.
The casting ridge kept getting in the way.
Thinking this casting ridge needs to go!
Plenty of material there so...
The spot where I think I'm going to drill.
So there is a casting ridge on that side of the pump that was in the way. It will not allow me to fully screw in the fitting, thus making the fitting stick out too far and hit the casing of the diff. The casting really has no function and there is a lot of solid material there, so I am not worried about shaving it off. Also, where I need to drill is not a flat surface, so I will already not be able to screw the fitting completely down. I need all the room I can get if this is to work at this spot.
That's it for now. Going to look things over a couple more times before I actually start drilling. I may get to it tonight. Slow progress, I know...
So I think the drill bit and the tap alone have put me over budget for this project. Anyways... after some careful eyeballing and puckering of my butt, I drilled into the pump housing. Did my best to make is straight with the angle I needed. It didn't matter so much what angel I went into the circuit to plumb the air. What mattered is how the 90 degree fitting sat outside of the pump as not to interfere with the diff casing. After tapping the hole and screwing the fitting in as far as I could, it was still hitting the casing just a little bit. I could close up the diff, but the fitting was hitting the case and I wasn't ok with that. I was so damn close and I didn't want to try start over with a new hole, so I decided to drill out the three mounting holes for the pump to the diff housing and "clock" the entire pump housing just a little. I think it will be alright, but time will tell. For now though, the fitting clears everything nicely and I do not have to modify the casing.
Pretty much just hoping for the best at this point.
JUST DO IT ALREADY!
Fricken laser beams!
No going back now.
Tapped and plumbed in.
The other side of this hole will be welded up.
This is as far as it will screw in.
Just barely hitting the casing.
Mounting holes for the pump housing.
Drilled out a little.
Clocked just a little.
Also drilled a hole in the casing for the bulkhead push-to-lock fitting. Airline is in there tight, but there are no kinks in it and it shouldn't move around at all. Tapped the holes in the circuit for the plugs. Didn't have to drill those at all, which was nice.
Plugged circuits.
Top plug is where the thermo switch used to be.
Again, needed to get this right the first time.
Bulkhead push-to-lock fitting.
Through the casing.
Routing of the airline.
Tight fit.
Tight, but no kinks.
Casing on!
This is the ARB air locker I will be using. It's a nice little unit that comes pretty complete minus the solenoid for some reason. It's cracking me up all of the "truck" parts that I will be putting on the Civic. Last thing to do with the diff for now it to weld up the one side of the circuit on the pump where the 90 degree fitting is. The hole is too big for a plug, so going to have to weld it closed. Maybe get that done next weekend hopefully. This week I will have my buddy take all the parts of the diff to work and put it in the hot tank for a good cleaning. I ordered new bearings and seals for the diff too. Gettin er dun!
Brakes... Not sure if anyone has noticed, but I am running OAF AEM BBK both front an rear. I really have enjoyed them and I am not sure why AEM got out of the big brake game, but the fact is that the parts are no longer offered. I have put these things to the test and driven them hard. But they now scare me to death when coming to a hard stop from high speeds as the Civic shakes violently. The fronts are covered with heat spots and show slight cracking from the drilled holes. It is time to replace them...
Bad rotor!!
I contacted AEM who then told me that STOPTECH had taken over their BBK production. So I contacted STOPTECH who told me that they would not sell me any replacement parts and that I would have to purchase all new BBKs. Now I'm not the smartest man in the world, but I'd say that they where not being completely honest with me and just wanted my $$. From what I remember the AEM BBK was pretty affordable back in the day. STOPTECH on the other hand, well I might as well go with BREMBO... So I continued my research elsewhere which lead me to Wilwood. Wilwood's BBKs are very affordable and great quality, but I have just never been a fan of the looks of their calipers and rotor hats for some reason. That and I think they really should just be on domestic vehicles. That's just my opinion and I am just rambling at this point. For some reason I am still partial to the looks of the AEM rotor hats and I want to keep them. So I continued to search on Wilwood's site, and happen to find that they make a rotor that is the exact same size as the AEM, same hat bolt pattern, and cross drilled and slotted. This allows me to use my same set-up as well as save me some money. That's the good news. The bad news is I am not so lucky with the rear rotors.
Wilwood rotors on AEM hats!
Unfortunately, they won't stay all black like this.
Now my rear rotors are still in pretty good shape and really do not need to be replaced at the moment, but one day they will need to be canned. While making the rear trailing arms for this project, I will also be converting them from drum to disk brakes. I figure this is the perfect time to replace the rear rotors so that I can set-up the caliper brackets to whatever rotors I choose to go with. The front and rear AEM hats are very similar and I think they did this to cut down on production costs. By doing this though, the rear rotor is "off set" instead of being a flat rotor. Wilwood uses a flat rotor in their rear BBK and accomplishes this by building the "off set" into the rotor hat. They also use a vented rotor for the rear, which means you have to use their caliper as Honda/Acura uses solid rotors in the rear. This starts to get pricy as I wouldn't use Wilwood's rear BBK with AEM's front BBK. Fortunately, Wilwood does offer flat rotors and a couple that even have the same bolt pattern as the AEM rotor hat. We can't stop there though I figured if I'm going to do all of this work that I would upgrade the rear caliper as well. I've been running the Integra rear calipers and decided I would go slightly bigger with the RSX rear calipers, which are the same calipers the ITR uses.
AEM rear rotor. You can see how it is off set.
Wilwood rear solid rotor. Flat, no off set.
So, if I'm going to upgrade the rear calipers... I always wished that I had spent the extra $$ and gotten the calipers that came with the AEM BBK back in the day. Being that the Civic is a DX, I had to swap out the front knuckles and calipers for EX stuff in order to run the AEM BBK. I had already done all of the work and was so close, but I never pulled the trigger on the Brembo's.... Till now. A little research revealed that AEM used Brembo rear calipers off of the Porsche Boxster. Today, these calipers are pretty easy to find for a decent price. After sourcing a set out, I contacted Fastbrakes who happens to be local to me, and talked to them about building some brackets to fit these calipers onto the EX knuckles. They said they had made some for that caliper to fit on an Integra, but never for a Civic. For the right price, they were up for the challenge.
Thanks Super Street.... Only pic I could find.
I know this is a little off topic for the AWD build, but actually it all had to be figured into the building of the rear trailing arms. Plus you get to see more pictures and I get to rant, so it's really a win-win! Thanks for tuning in.
On the two piece brake rotors, what size bolts are they - 5/16" or maybe 1/4"?? I hope they're at least 5/16" bolts, as I've had an issue with two piece rotors shearing off 1/4" bolts on track even with grade 8 bolts, but I also had a brake shudder issue which may have caused some of the issue. The main thing is that 5/16" bolts are quite a bit stronger and larger in diameter and area than 1/4" bolts, so hopefully they're at least 5/16". Also, the pictures appear to show just a cross on the top of the bolts - I'm used to 3 lines for grade 5 and 6 lines for grade 8, but I don't recall seeing a bolt with a cross on the top. What grade are they? Great work on the project, and looks like it will be a heck of a lot of fun to drive. - Jim
I'm used to 3 lines for grade 5 and 6 lines for grade 8, but I don't recall seeing a bolt with a cross on the top. What grade are they? Great work on the project, and looks like it will be a heck of a lot of fun to drive. - Jim
I'm really not sure what grade or size the bolts are. I would think a company making rotors would use grade 8, but you never know I guess. I may end up replacing the bolts after everything is working and powder coated. It's scary to think that you can shear off bolts on a rotor. Thanks for the complements and checking out my build. I hope the Civic will be a lot of fun once finished. Just gotta get er dun.
05-25-2016, 04:19 PM
Re: Not Another AWD Civic Project!!!
As you can see there wasn't any clearance issues with the down pipe and dump tube. It actually worked out great! 
I had to get a new 90 degree silicone hose for the turbo to reach the inlet of the intercooler. That was a little tricky as the new manifold moved the turbo downward and towards the block more. I think I got it though. It's kind of crazy how you really can't tell that there is an AWD transmission in there. The only thing that gives it away is the placement of the starter and that's if you happen to notice it. You really have to get in there and look around for the cables now that the intake piping, radiator hoses, and catch can hoses are in place. Now that the front is done, it's time to tackle the rear. I'll be opening up the rear diff and hacking away at it. Stay tuned!!
Yup, that makes two of us. If I could have it my way though, I would like it react the way it was designed while having the ability to fully lock up for launches. Unfortunately, it won't work that way. I do think it will be pretty cool to pull up to the burnout box on the strip, roast the front tires, and then skate off the line in AWD. That should make some people scratch their heads. 
I may get to it tonight. Slow progress, I know...
This allows me to use my same set-up as well as save me some money. That's the good news. The bad news is I am not so lucky with the rear rotors. 
I figured if I'm going to do all of this work that I would upgrade the rear caliper as well. I've been running the Integra rear calipers and decided I would go slightly bigger with the RSX rear calipers, which are the same calipers the ITR uses. 
