AWD Speed 3 Project - Halfmilespeed3

Hello Guys & Gals,
As winter rolls in here in the PNW, I am preparing my car for an AWD swap. I see that @Roger Mesler has been doing fantastic work with his and I have gleamed some info from it; thank you. While I haven't been great about documenting the many phases my car has gone through, I want to document this phase for the sake of the community. I think have more than one step-by-step available to people would be great.

The car in question is my 2009 Mazdaspeed 3 that I have been modifying and building for half mile drag racing for the past couple years. The power plant is an Overspeed built block with all the CS goodies and some custom one-off items I've built myself and with local friends. With the Xona 9569s turbo, I am touching 900whp to the front. IG: @halfmilespeed3

The parts I've collected so far:
- Speed 6 Trans
- Speed 6 T-Case
- CX-7 T-Case (edit not needed)
- CX-7 rear suspension (complete from rotor to rotor) (Edit only need teh center subframe and diff)
- CX-7 mid-driveshaft (might be able to use some of it)
- Speed 6 OEM AWD control module

Parts I'm still looking for and /or will need:
- Speed 6 Front LSD (edit sourced from Damond Motorsports)
- Speed 6 rear diff to pull the LSD from
- Modify Passenger Front DSS 5.9 CV Axle
- Custom length rear axles TBD
- Custom mid-driveshaft setup TBD

My first priority is to get the system 100% installed and functioning to a confident useable state.
Next would be removing excess weight that is not needed.
Lastly, my end goal is to made a tubular rear subframe to really reduce weight, but I need all the kinks worked out of the system.

Hold me accountable to posting and keeping this update. This may be an early post to make, but best to get started now I say.

 

Did the speed6 come with a front lsd? I always thought that it was an open diff.

 

Open front diff IIRC, I think phate put an LSD in front in his.

 

@phate

 

Factory is open diff in the front. I'm wanting to source one so that I add that when I add the dog box gearset.

 

Are they the same as ms3? Or does the PTO connection make it different

 

Unfortunately they are unique due to the PTO connection. From my research, only Damond has developed one and that was a group buy they did awhile ago.

 

Phate was selling his chassis a while ago

 

I suppose I could ask him about the transmission. Not sure if he is open to parting it out a bit.

 

It has been for sale for a very long time...

 

I talked to him. Not interested in parting out right now and I'm not buying a whole car haha

 

For what your doing it would be much easier to just stick a motor into phates car

 

Ya maybe a few years ago but I have alot invested into my chassis at point and want to stick with the novelty of it.

 

Quick update: Has nothing to do with AWD swap, but I pulled the turbo out to do a rebuild with a new compressor wheel and compressor housing from Xona Rotor. The new wheel paired with a larger compressor housing is much more efficient and should result is same or more power at a lower boost pressure. This is key as I'm riding the limits of my current headstuds.

95xx X3C is current
99xx X4C is new hotness

To use this larger compressor housing I'm making some additional clearance for the comp housing. The exhaust manifold flange on the driver side creates a channel/path for the EGR off cylinder 4 to route to the EGR valve. When my engine was built by Overspeed, he welded the side of the port closed and provided a new gasket to correctly seal it. SO I don't have an EGR port at all.
With that I can cut this section of the flange off and provide another ~3/4" of clearance for a larger compressor housing.

 

An AWD MS3 just popped up on BaT; the build may give you some ideas, linky.

 

how the hell has that car been around for so long and we didnt know about it.

also uses a shocking amount of stock parts from other cars. reading the description it seems like the rear control arms, one front axle, driveshaft and exhaust are the only custom pieces.

 

I talked to the owner a bit. He worked directly with AWR/DG Motorsports to do the build. Knowledgeable guy and had the goal to keep the car very OEM like with that build. Moving on now because he jsut doesn't have interest and is boosting his SC400.

He kept the CX7 outer suspension components. I'm on the fence about that or keeping the MS3 outer components since the CX7 more complicated and looks heavier.
CX7 has a vented rotor with an inner parking brake like a drum brake.

I plan to find out more this weekend as I'll be puling the OEM rear subframe/suspension out of my car and comparing directly.

 

Quick update this am: Worked on the rocker arm design. This will be a billet 6061-T6 AL material and fully CNC machined.
Ratio is 1:0.7
This gives me more suspension travel for a shorter damper but I will need to run a stiffer spring rate to compensate...around 500-550 lb/in in the rear to start.
The pivot for the rocker arm will use sealed roller bearings.

 

Update from the weekend:
- Overall, the process has been pretty straight forward and after some trial and error.
- CX7 rear end in a whole is not the solution. It is a combination of CX7 and MS3 components to get the proper track width.

Images showing removal of components:
- IMG_3816: Weighed the car at "race trim" minus the driver so I have a baseline to compare to.

- IMG_3817: Rear subframe removal was pretty straight forward. There are 6 total 17mm bolts holding the subframe to the chassis and 4 total 17mm bolts holding the leading pivot of the trailing arm tot he chassis. The EVAP/Fuel Tank assembly has some various wires and M6 hardware attached to the subframe that you have to remove.
- IMG_3818, 3820 & 3822: The fuel tank assembly is also stupid simple to remove especially with the rear subframe out of the way. The filler neck has a couple screw that you access through the filler door. Then you have a wiring harness connection and fuel out feed line it the top of the tank under the access panel. From there, its 3 12mm bolts that hold the tank in place via the straps. Make sure you have less than a 1/4 tank of fuel when taking out (just to simplify things).



- IMG_3823 & 3825: I cut the feed line since I won't be reusing the OEM plastic fuel line, but I did mark the steel hardline because I will be reusing it to feed the DI fuel only.


- IMG_3826 & 3827: Now with all the room for activities I could start prepping for a mock up test fitment. You'll not that I remove all the heat shielding underneath the car. I did this because I do not need it. My exhaust exits via the hood so any weight removal I can do easily, I will do.

 

Continued update so each post isn't too overwhelming.
- IMG_3828: I knew the front section of the spare tire tub needed to be trimmed and I knew that I wanted very easy access later on so i opted to cut the entire spare tire tub out of the chassis. This may not be the goal for others, but in my racecar specific case, it was the best path for me and will affect overall weight changes.

- IMG_3829: Here is a top view of the MS3 complete rear sub assembly (top) vs the CX7 complete sub assembly (bottom). They are facing opposite directions so I could better line them up and compare.
I can confirm a few things that i had been told before starting this project:
1) The 6 chassis mounting holes are in the same location and widths
2) To the best of my ability I could confirm that the inboard pivot locations for the lower control arm, camber arm and toe arm are in the same locations
3) The brake systems are complete different:
- The MS3 is a solid disc with the parking brake incorporated into the normal brake caliper. This is a simple and typical system.
- The CX7 is a vented disc (which is better) but the parking brake is a drum brake that resides inside the rotor have of the disc rotor. i've seen this system on bigger 3/4 and 1 ton pickups (my 04' Dodge uses this system). Its a PITA to deal with, is complicated and expensive. Not idea for racecar so I was not enthused to use that system.
4) The trailing arm/assembly:
- The MS3 visually appears to have a longer trailing arm section but measurements say otherwise. Its also a much less complex and lighter duty design. this is expected as its not AWD and it was not designed for an SUV from the factory.
- Likewise, the CX7 appears shorter but measures the same. I think this is due to the beefier design. The arm design also has less "swan neck curve" to it which may prove to be an issue.
5) Control arm lengths: All the CX7 control arms are longer. Track width of the MS3 is 60" rear whereas CX7 is ~64" so this makes sense.


So now let's mock it up and see:



Don't mid the high stance, I did not remove the OEM springs from the CX7 subframe. This would jsut an initial mock up to verify everything bolts in.
- Confirmed the subframe just bolts right in...kinda silly to be honest.
- As you can see, the track width is too wide...I'd say 2" to wide on each side...BUT this could be a very viable solution for anyone looking to do a legit wide body kit and not just using wheel spacers. (My gut says you could do this is a FWD fashion also, jsut using the CX7 control arms).
- Wheel centering in the fender arch looks good so I think we are on the right track.