Rear axle cooler

[ek1]

2016 ACR manual says "NOTE: For track outings lasting longer than 25 minutes, an external
rear axle cooler is recommended.". Speaking with Mark Jorgensen @ Woodhouse, it's not actually possible to buy the cooler. Apparently, there is also no temperature sensor in the rear axle, so if you overheat it and cook the fluid, you would not even know it.

Does anyone have any sources/solutions? As per Mark, the old axle coolers made for earlier Vipers would still fit a 2016. Where can I buy a used one?

[Rapidrezults]

I also found this strange. All of the launch publications included information regarding this "finned differential cooler" ...

From the FCA 2016 Viper press release: http://media.fcanorthamerica.com/newsrelease.do?id=16752&mid=

2016 Dodge Viper ACR
Standard equipment includes:
8.4-liter, overhead-valve, 20-valve, SFI, all-aluminum V-10 engine
Six-speed manual transmission
ACR double adjustable suspension with 10 rebound and compression settings and Bilstein coil-over racing shocks
Brembo Carbon Ceramic Matrix two-piece rotors with six-piston front brakes
Rear aero wing
Lower dive planes and carbon front splitter
Unique race alignment and race-tuned five mode, electronic stability control (ESC)
SRT hood
19 x 11-inch front, 19 x 13-inch rear; ACR Gloss Black wheels
Kumho 295/25ZR19 front, 355/30ZR19 rear BSW tires
Finned differential cooler
ACR lightweight Interior
Alcantara wrapped steering wheel with racing stripe, console, dash and door trim panels
Unique accent stitching throughout interior
3-speaker audio system
Lightweight battery

[steve911]

I have a "cloned" ACR-X diff cooler on my car. It consists of a pump, cooler, temp sensor, custom made wire harness with weatherpack connectors, relays, fans and hoses. The cooler only activates when the diff temp gets to 190 degrees., and shuts off at 165. That equates to 2 laps at road America when it turns itself on.

The original cooler kit was $1440.00 through Mopar. I made or bought everything exactly as supplied by Dodge and I still have $600.00 into it, and most items were bought wholesale. There is quite a bit of labor to install one. I have done 4 cars in my area. I attached just a few pics to give you an idea.

I do have one on my Gen V. As the old saying goes, "An ounce of prevention is worth a pound of cure".


15835158361583715838

[LATAMUD]

I put together a similar kt as Steve above. I just bought all the components separately, Tilton makes a decent pump, 8-10" electric fan, found a used heat exchanger for $50, painless wiring relay kit, AN-8 hose and fittings. And did the same thing for my transmission cooler.

[01sapphirebob]

I also found this strange. All of the launch publications included information regarding this "finned differential cooler" ...

From the FCA 2016 Viper press release: http://media.fcanorthamerica.com/newsrelease.do?id=16752&mid=

2016 Dodge Viper ACR
Standard equipment includes:
8.4-liter, overhead-valve, 20-valve, SFI, all-aluminum V-10 engine
Six-speed manual transmission
ACR double adjustable suspension with 10 rebound and compression settings and Bilstein coil-over racing shocks
Brembo Carbon Ceramic Matrix two-piece rotors with six-piston front brakes
Rear aero wing
Lower dive planes and carbon front splitter
Unique race alignment and race-tuned five mode, electronic stability control (ESC)
SRT hood
19 x 11-inch front, 19 x 13-inch rear; ACR Gloss Black wheels
Kumho 295/25ZR19 front, 355/30ZR19 rear BSW tires
Finned differential cooler
ACR lightweight Interior
Alcantara wrapped steering wheel with racing stripe, console, dash and door trim panels
Unique accent stitching throughout interior
3-speaker audio system
Lightweight battery

The GEN V ACR diff has fins on the diff for cooling.

[str5010]

Above is correct. To clear up confusion the differential housing is shaped to promote heat transfer (fins) by itself to help cool the fluid. An auxillary fluid cooler can be added as mentioned to actively cool the differential fluid through a dedicated heat exchanger and return the fluid to the differential.

[ek1]

Does anyone happen to have some pics showing the cooler installed on their car?

[steve911]

Does anyone happen to have some pics showing the cooler installed on their car?

Why yes I do. The cooler assy mounts to the bottom of the trunk floor and the pump mounts to the cross member behind the diff. The fans are on the forward side of the cooler and blow to the rear.
15876

[ek1]

Thank you! Now I have a much better understanding of the setup.

More questions if you dont mind:

Did the inlet and outlet fluid ports come from the factory or did you have to drill those holes and thread them yourself?

Since you may have seen pictures of the ACR's rear end, do you think that the cooler will clash with the covers and diffuser strakes on the ACR? Looks like it may.

[ek1]

By the way, here is an interesting article on differential coolers:
http://www.turnology.com/tech-stories/fuel-cooling/what-you-need-to-know-about-differential-and-transmission-coolers/

[Dfunk]

Very good info. The cooler will be overkill for me. The track days I plan to attend won't allow me to be out more than 25 minutes anyway. Changing the diff fluid after every event is my plan.

[ek1]

So far all the track events I attended also topped out at 25 min sessions as well. Apparently there are some venues that have open track time, meaning the track is open for hours and if you sign up for an event, you can drive as long as you want. I am looking for those events.

I am also planning to try and drive in more than 1 group at regular track events I attend.

The biggest problem is that there is no temperature sensor in the axle, so you would never know if you are overheating the fluid. Once you do overheat it, it loses it's cooling and lubricating qualities and then you have a damaged diff. I think I have seen a thread here that replacement diffs currently have a 2-3 month lead time, which for me is half of my yearly driving season. I just dont want the pain if I can avoid it.

[steve911]

Thank you! Now I have a much better understanding of the setup.

More questions if you dont mind:

Did the inlet and outlet fluid ports come from the factory or did you have to drill those holes and thread them yourself?

Since you may have seen pictures of the ACR's rear end, do you think that the cooler will clash with the covers and diffuser strakes on the ACR? Looks like it may.

The diff comes with plenty of predrilled and tapped holes. No need to do anything yourself.

The cooler assembly actually mounts to the bottom of the trunk floor and exhausts thru the vent at the rear of the car. Not in the way of anything as you cannot see it by looking at the car. It sits above the rear diffuser panel.

[Jack B]

That is pretty slick. I would guess, even on the highway you are going to hit 190 deg F. i have some wireless thrmocouples that are slaved to a logging DDM, I will put one on the outside of the diff in the near future, just to see what the normal operating temps are.


Why yes I do. The cooler assy mounts to the bottom of the trunk floor and the pump mounts to the cross member behind the diff. The fans are on the forward side of the cooler and blow to the rear.
15876

[MomentaryRacing]

We built our own using some AN lines, T for the sensor, and a small pump. We ended up programming MoTeC dash to turn the pumps on every 2 minutes to cycle the fluid so temperature reading is correct, and then activate fans and keep the pump on if it exceeds about 200 degrees.

This is gen4 diff with 3.07:1 ratio. On a colder day, we saw temperatures stay below 160 degrees for extended sessions, until we blocked off the "passive" cooling airflow and went to "sampling" only pump activation until working temps are reached.

Now we can bring both trans and diff temps up to 190-210 degree range in about 10 minutes, and keep them there indefinitely.

If anyone is building this stuff, and you are looking for specific parts (pumps, sensors, etc), feel free to PM us and we will share details.

If you do not have access to programmable controller, thermostats are highly recommended, we had serious issues with gearbox when we were over-cooling.

We ended up taking out Tilton pumps as they are very heavy, and we felt are over-built for the application. We returned one, and use the other one for oil changes :)

Both trans and diff pumps we use now, combined, are lighter than a single Tilton unit! Tested in 6 hour and 1 hour endurance races, and multiple sprint events - so reliability is not an issue. They use a lot less power too, and are very quiet.

P.S. With no cooling, we saw temperatures approach 300 degrees on both gearbox and diff, in 20 minute test sessions at cool ambient temps (<60F). So both need cooling unless you like to rebuild often, or don't like to use 2nd gear :)

[steve911]

The temp sensors in both the trans and diff in my car cycle on at 195 degrees and cycle off at 165. No issues ever equipment wise since I installed 3 years ago.

[Stubbygda]

[QUOTE=steve911;204583]I have a "cloned" ACR-X diff cooler on my car. It consists of a pump, cooler, temp sensor, custom made wire harness with weatherpack connectors, relays, fans and hoses. The cooler only activates when the diff temp gets to 190 degrees., and shuts off at 165. That equates to 2 laps at road America when it turns itself on.

The original cooler kit was $1440.00 through Mopar. I made or bought everything exactly as supplied by Dodge and I still have $600.00 into it, and most items were bought wholesale. There is quite a bit of labor to install one. I have done 4 cars in my area. I attached just a few pics to give you an idea.

I do have one on my Gen V. As the old saying goes, "An ounce of prevention is worth a pound of cure".




Steve do u have a vendor/parts list for this setup? Or a kit u sell? I am interested in putting one on my ta 2.0. I have found some coolers i think will work but no need to reinvent the wheel since it looks like u figured it out already.

[ACR Steve]

somebody sell the kit ..............please lots of guys need it

[XSnake]

somebody sell the kit ..............please lots of guys need it

is Tom F not selling them?

[ek1]

Who is Tom F?

I am looking for a turn key install on my Gen V ACR

[1of1TA1.0]

Tom Francis with DMS South (Parts for Comp Coupes as well as ACRX)

[1of1TA1.0]

Pics of a set up I did, all told it was pretty close to $1,000 with all parts, sensors, lines etc.... As with others, this is a knock off ACR X piece

http://i74.photobucket.com/albums/i277/F8LSNK/ACR%20to%20ACRX%20Photos/DSCN0797.jpg (http://s74.photobucket.com/user/F8LSNK/media/ACR%20to%20ACRX%20Photos/DSCN0797.jpg.html)

Here are a few of the ACR X transmission cooler if anyone is interested (purchase from DMS)

http://i74.photobucket.com/albums/i277/F8LSNK/ACR%20to%20ACRX%20Photos/IMG_0475_2.jpg (http://s74.photobucket.com/user/F8LSNK/media/ACR%20to%20ACRX%20Photos/IMG_0475_2.jpg.html)

http://i74.photobucket.com/albums/i277/F8LSNK/ACR%20to%20ACRX%20Photos/IMG_0472_2.jpg (http://s74.photobucket.com/user/F8LSNK/media/ACR%20to%20ACRX%20Photos/IMG_0472_2.jpg.html)

[Simms]

Tom Francis with DMS South (Parts for Comp Coupes as well as ACRX)

Tom is a great guy.

[ACR Steve]

I was told they no longer sell the kit?

[bluesrt]

where did you guys get the temp sensors at ?

[1of1TA1.0]

I got mine from Tom, it was the only piece I couldn't find a good source on.

[MomentaryRacing]

All parts together are A LOT less than retail on the kits we saw, when we first built the car. Of course, you are getting the benefit of someone else's R&D :). On the other hand, if you are a DYI type (mounting coolers, fans, AN lines and some wiring) or have access to a competent fabricator, drop us a message. We are building parts list for the system we run (to those of you who already messaged us - sit tight - the car is getting the drivetrain serviced in about a week, we will have the info then.)

[Tamvette]

Any update on this? I am also available for testing at the Ridge if you guys need : )

[lmcgrew79]

I was considering one of these setrabs link below, already has the fans just needs a pump, wiring, lines and mounting bracket of some sort.

http://setrabusa.com/products/fanpacks/fp920m22i/index.html

[Stubbygda]

i was looking at a very similar derale unit. my question is does anyone know what the specs should be for the unit. what size is right size. too much cooling and pump cycles too much. not enough and it stays on all time and maybe never gets to right temp. anybody have the btu and cfm specs on unit sold acrx or comp coupe or specs on a unit they r using and it works correctly????

[steve911]

i was looking at a very similar derale unit. my question is does anyone know what the specs should be for the unit. what size is right size. too much cooling and pump cycles too much. not enough and it stays on all time and maybe never gets to right temp. anybody have the btu and cfm specs on unit sold acrx or comp coupe or specs on a unit they r using and it works correctly????

You are over thinking it.
There are several threads on this, a couple of which I started. The diff coolers are thermostatically controlled for the pump. They turn on at about 200 degrees and turn off at 165 degrees so they will not over cool or under cool. Have used this same cooler on my Gen 3 and my Gen 5 car.

The one I use is a copy of the ACR-X (2010) that I made. It uses 2 3” axial flow fans mounted in a shroud, that is bolted to the underside of the trunk floor behind the diff in the airflow that exhausts through the rear of the car. Power is routed through a 50 amp relay that is wired into the battery with a switch that is normally off unless I am at the track. Thermostat is plumbed into bottom of diff.

Using Road America as an example, the cooler will normally come on after about 4-5 laps depending upon ambient temp. It will cycle on and off, mostly on, for the session. After returning to the pits, it will stay for about 2-3 minutes then shut off.

My trans cooler is the same way. It uses the diff cooler thermostat to control the pump.

[JGK95]

Hi Steve, when I see you on Monday at Autobahn, please take a minute to talk to me about building one of these.

Thank you,

Jay K.

[Arizona Vipers]

Doug Shelby makes a complete kit now- http://www.dougshelbyengineering.com/viper.html

[gpbtt]

I have the Doug Shelby Cooler......very good and well thought out......comes with everything you need!
You can't go wrong with Doug's set up!

[Bryan Savage]

I was tipped off by Autoweek about a series of great videos on differential cooling from Banks Power that were made in 2018. If you have an hour and change, you should definitely check them out. They're geared to big trucks, but the principals are the same for all vehicles.

Part 1: 9:59

https://www.youtube.com/watch?v=n4DQ-jzKQRw

Part 2: 19:39

https://www.youtube.com/watch?v=09JsDorR6tw

Part 3: 12:08

https://www.youtube.com/watch?v=0PMvVcsU3PE

Part 4: 33:46

https://www.youtube.com/watch?v=vdtmDl5EDJ8

It got me thinking about the diff covers in the Gen V. Mine is the same diff cover as the Gen IV, as it's got a Fangs logo cast into it.

44460

ACR diff covers have cooling fins on them though. Has anyone ever rigged up a temperature gauge and compared the two different covers?

Looks like the part number for mine supercedes to the 2017 cover, so on later-than-2014 cars, do all Vipers have finned covers?

44459

From some of the above posts in this thread, temperatures with no cooler were getting up to 300°F, and the coolers were set to around 195°F. As Gale Banks explains in the videos, and as we all know, fluid temperatures are usually only this high to boil off any moisture that gets mixed in with them. Colder fluids are not better, so taking the thermostat out of your car isn't going to do your oil life many favors.

Both Doug Shelby Engineering and TKO Motorsports make transmission and differential cooler kits now.

DSE (Doug, please add separate pages of part categories to your site. The "one long-ass page" format is a pain. lol)
http://www.dougshelbyengineering.com/viper.html

TKO
https://tkomotorsports.com/product-category/drivetrain/differentials/

Both of these coolers have slightly different designs. The DSE kit has a cooler that "faces" the assumed airflow direction under the car, but the TKO kit mounts perpendicular to the airflow, likely due to the larger core and the cavernous space afforded by the Gen V. And as all coolers, you need a fan, so that negates a bit of the airflow question. I would expect the TKO kit to need to use the fan more often, since the core isn't facing the airflow, but I am only assuming what the airflow under there looks like. It might be a turbulent mess.

These Banks videos had got me thinking about what's going on with the airflow under the car. All Gen V cars have that aluminium plate underneath with that not-a-NACA-duct inlet to scoop air towards the differential and out the back above the tailpan.

But what's the actual airflow under there doing? It's a pretty shielded place, and aside from air that gets above the aluminium plate near the transmission or through that scoop in the plate, no other air is going up there. The differential is tucked up under the car pretty well, so the differential is not getting the airflow that Banks' big trucks are getting.

It's not like SRT doesn't know what they're doing, so my stock differential is likely fine, as long as I'm not pounding the crap out of it on track all day, but I'm still curious now about how much airflow I'm getting, what my temperatures are doing, and how much benefit the finned covers provide.

Discuss!!!

And for the love of all that is holy, please don't "reply with quote" and reprint this whole post for a one-line reply.

[TKO MOTORSPORTS TEAM]

444614446244463
We have had our diff cooler kits available for 3 years now. Properly engineered and track tested.
TKOSROD1277K 5th GEN VIPER RACING DIFFERENTIAL COOLER 1856.39
• Differential cooling is one of the most overlooked areas on performance-based vehicles. 5th Gen Vipers with their much-improved performance over earlier models need cooling of all fluids as much as possible. Our differential cooler kit allows you to keep the differential oil temperatures below 200 degrees even weight billet aluminum powder coated mounting bracket
• Steel braided AN lines and fittings (also available with light weight nomex AN lines
• All necessary hardware for a complete and easy installation
on the most demanding track days with the simple flip of a switch. Installation is very easy and completely hidden under the rear of your Viper.
Kit comes complete with:
• Completely self-contained unit ready for install
• Complete wiring harness
• Automatic temperature control unit on/off automatically
• High volume 1000 hr endurance racing sealed electric pump
• High volume Setrab aluminum oil cooler