CX-90 Turbo S vs. Turbo Differences and drivetrain notes

Found some parts dealers with service / part diagrams posted on the web, and came across this interesting bit.

There is a differentiator for a 3.3L w/ sub-radiator & 3.3L w/o sub-radiator. By looking through all the parts diagrams, this sub-radiator feeds the air-to-water intercooler. When the sub-radiator isn't used, water is sourced from the main radiator. I am fairly certain this is one hardware difference between the base and higher output engines, which makes sense from a reliability standpoint.

The only reason to have this differentiation would be the additional heat management coming from the higher output engine.

EDIT: It looks like this guess is likely incorrect. Additional radiator appears to be tied to towing capacity, as there are the two lowest trim non-S models that have a lower towing capacity.


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Other interesting bits of info from the powertrain.

Only one turbocharger part number.

There may be two part numbers for engine short block assemblies. They are so close together though it could be just a notation thing. Only appears to be one part number for a long block though, so leaning towards the internals being the same between the two engine variants.

Approx. long block cost is $9300.

Approx. transmission cost is $13k.

Front differential is mounted to the oil pan (with one half-shaft going through the oil pain) like a RB26 (R32-R34 Skyline GT-R).

I cant find anything on the wet-clutch pack or MHEV motor, I am assuming that may all be baked into the "transmission" considering its outright cost.

It would appear it goes engine -> flywheel/damper -> transmission (Wet clutch pack->DC Motor-> transmission gear shafts -> transmission output shaft) -> transfer case (center diff) -> front / rear diffs.

Just drawing conclusions on this setup based on notes for the 3.3 and the 2.5 phev that have been released thus far. This would mean the transmission likely is a true automated manual (single clutch, not dual clutch).

The transfer case / center diff resembles a 4wd transfer case, which means that the RWD link is likely mechanical (in an AWD failure mode, drive may become 100% RWD or a high split 80/20) and the FWD link is likely parasitic to the main drive line (hence the rear-wheel drive biased).
 
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The sub radiator difference could be something else than the high output. Like it could be for the Australia vs North america market, or could be for the towing package.

For example, the CX-9 outside of america has an additional oil cooler.
 
Like I said, because it is a separate loop that feeds the air-to-water intercooler directly, it has to be for the performance side. Ill confirm this weekend when I look on my TS. If this is the case, upgrading the sub-radiator may be a useful upgrade, as upgrading the air-to-water intercooler isn't going to be very feasible with how it is tucked under the intake manifold.

EDIT: See first post edit.
 
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Just drawing conclusions on this setup based on notes for the 3.3 and the 2.5 phev that have been released thus far. This would mean the transmission likely is a true automated manual (single clutch, not dual clutch).
I think that is exactly it.

The motor effectively provides the equivalent torque converter function just to get the vehicle moving. Once moving, the clutch comes in and it’s a direct mechanical connection after that (aka automated manual).

It‘s a clever solution that improves efficiency by completely eliminating the fluid coupling losses.
 
Just wanted to update this post as I believe my original theory was wrong.

There were many parts of the diagrams that were hard to follow / unclear exactly where they routed (between pages of the diagrams). I originally had made some educated guesses. After having another user point me to specs sheets, it seems the sub-radiator is actually just tied to the 5k towing capacity vs. 3500 towing capacity as seen via coolant capacities broken down in the user manual spec sheet. The additional cooling radiator appears tied into the high voltage converter and transmission.

The A2W intercooler is apart of a separate cooling loop (main radiator is a two core radiator, one for the engine / transmission, one for intercooler) with an electric water pump. Good news is this provides a good place to provide additional cooler capacity and a chiller tank as aftermarket modification sources.
 
In regards to the transmission I am working on a video similar to some of the others I've made around the newer Mazda technology. The wet clutch that is used to get the vehicle moving is the same design as the other clutches inside the transmission, it uses very precise control to slip from a start until the vehicle is moving and then locks tight, it slips in 1st and reverse and then is applied until 6th gear. The clutch set is in the rear of the transmission and sits in front of the two rear planets and is splined to the front one. As it slips it transmits the power to that planet and the output shaft. In the cutaway picture I've circled them in red.

The transfer case has a coupling in it supplied by JTEKT like the FWD units but pulls power forward. Second picture is the clutch inside the transfer case.
 

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In regards to the transmission I am working on a video similar to some of the others I've made around the newer Mazda technology. The wet clutch that is used to get the vehicle moving is the same design as the other clutches inside the transmission, it uses very precise control to slip from a start until the vehicle is moving and then locks tight, it slips in 1st and reverse and then is applied until 6th gear. The clutch set is in the rear of the transmission and sits in front of the two rear planets and is splined to the front one. As it slips it transmits the power to that planet and the output shaft. In the cutaway picture I've circled them in red.

The transfer case has a coupling in it supplied by JTEKT like the FWD units but pulls power forward. Second picture is the clutch inside the transfer case.
Interesting, do you know / can you explain where the 48V electric motor sits in relation to all this? My original assumption was that the transmission was functionally a single clutch automated manual, but if there are multiple clutch packs in the transmission, that guess was wrong.

Orig assumption was engine flywheel damper->clutch pack -> 48V elec motor-> automated manual gear set->output shaft. The thinking was that the electric motor would aid getting the drive train moving and aid the slipping actuation of the primary clutch....
 
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Yes, it sits in between the engine and the transmission proper. There is a damper in between the motor and the engine, and a wet clutch inside the motor to decouple it from the transmission. Internally it is built like any other planetary gearbox. There are four planets, 3 driving clutches and 2 brake clutches. The clutch set that slips is called the B2 and is considered a braking clutch.
 

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Thank you for the details, certainly explains the potential sources of drivers into the slow speed operation / harshness in up shifts / downshifts sometimes experienced. Probably explains the poor off-the-line performance seen in the CX-90/Mercedes/BMW video as well (Am thinking in terms of complexity, many operations/events going on from a complete stop).

Are you an Engineer with Mazda?
 
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Thank you for the details, certainly explains the potential sources of drivers into the slow speed operation / harshness in up shifts / downshifts sometimes experienced. Probably explains the poor off-the-line performance seen in the CX-90/Mercedes/BMW video as well.

Are you an Engineer with Mazda?
Not an engineer for Mazda, just in the industry specializing in engine/transmission.
 
Well if you have any way of communicating feedback since you are in industry (longshot I know), I think there are still things that need to be ironed out with the controls surrounding this non-TC hybrid transmission setup. There are times where the NVH associated with the synchronizing of the engine auto-start-stop (iStop) / mild hybrid motor / regenerative braking really hurts the driving dynamics of the platform (which much of the time are very good for an SUV of its size).

I am sure some of it is just things breaking in, but there are definitely some sub-optimal edge cases that actually come up pretty frequently.

Now that I know the design of the transmission, I at least understand that the tuning / synchronizing of all these components is not a simple task.
 
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Can you confirm if the transfer case is capable of being fully un-coupled / variably coupled? (Making the platform effectively RWD or variable torque split F:R)

The transfer case has a coupling in it supplied by JTEKT like the FWD units but pulls power forward. Second picture is the clutch inside the transfer case.
 
Can you confirm if the transfer case is capable of being fully un-coupled / variably coupled? (Making the platform effectively RWD or variable torque split F:R)
Yes it does have the ability to completely decouple sending power to the front and is highly variable in the power it can transfer. This diagram shows powerflow through the unit. Some of the clutches are splined to the main shaft and the other clutches are splined to the shaft going to a reduction gear in the front that the front driveshaft is hooked to. Depending on the clamping force of the clutches will determine the amount of power added to the front.
 

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Yes it does have the ability to completely decouple sending power to the front and is highly variable in the power it can transfer. This diagram shows powerflow through the unit. Some of the clutches are splined to the main shaft and the other clutches are splined to the shaft going to a reduction gear in the front that the front driveshaft is hooked to. Depending on the clamping force of the clutches will determine the amount of power added to the front.
Thanks for the info! Have you had a chance to drive a CX-90 yet (or CX-60 assuming its the same trans)?
 
If you get the chance to spend some time driving one, please let us know your feedback! It is very difficult to describe the clunky / harshness sometimes experienced. The other misgiving is odd kinds of hesitations (either mechanical, or a noticeable enough of an input delay between pedal input and torque delivery that goes against what those who have driven traditional TC boxes would be used to). Its not a misfire hesitation, I think its more likely that there are certain operations that once started have to be completed before the next can occur, and certain pedal input combos trigger this.

Since I have spent much of my life driving manual, the hesitation / delay that occurs sometimes is almost triggering my brains "you stalled" response.

I am being very critical of the platform, but its very much a 90/10 problem. A majority of the time things are very good, but the times that aren't are very odd / different from other misgivings I have had with other cars and thus don't know what to make of them (other then hoping they are fixed with updates). Jumping from a vehicle with a TC auto into these takes some adjustment to driving patterns.
 
If you get the chance to spend some time driving one, please let us know your feedback! It is very difficult to describe the clunky / harshness sometimes experienced. The other misgiving is odd kinds of hesitations (either mechanical, or a noticeable enough of an input delay between pedal input and torque delivery that goes against what those who have driven traditional TC boxes would be used to). Its not a misfire hesitation, I think its more likely that there are certain operations that once started have to be completed before the next can occur, and certain pedal input combos trigger this.

Since I have spent much of my life driving manual, the hesitation / delay that occurs sometimes is almost triggering my brains "you stalled" response.

I am being very critical of the platform, but its very much a 90/10 problem. A majority of the time things are very good, but the times that aren't are very odd / different from other misgivings I have had with other cars and thus don't know what to make of them (other then hoping they are fixed with updates). Jumping from a vehicle with a TC auto into these takes some adjustment to driving patterns.
I do intend to have some seat time with one asap. There is quite a bit involved in getting them rolling, I have no doubt there will be ECM/TCM updates as the platform ages.
 

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Turning off the auto-start-stop definitely improves some of the transient state cases, where bad timing plays a role.

Pretty much any driving in 1st/2nd that is transient between pedals (braking -> coast -> accel) or (braking -> accel) at slow speeds seems to be where weirdness crops up.
 
I do intend to have some seat time with one asap. There is quite a bit involved in getting them rolling, I have no doubt there will be ECM/TCM updates as the platform ages.
Since you have access to the underlying components, could you look at the rear diff and see if the older CX-9 LSD or something similar could be swapped in? Prior to buying not having a LSD in the rear was my biggest concern for low traction environments (snow etc), I am not a fan of electronically controlled braking open diff "locking" diffs. Thankfully I know there is a good chance of finding a mazda or ford LSD that can be swapped in.
 
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