IRS Differential Cooler

[VNEMUS]

Anyone (other than Cobra R guys) running an IRS Differential Cooler Set-up where the oil pump and cooler are mounted externally in the rear of the car?

If so, can you provide details of the following:

- What brand oil cooler you are using and what are the dimensions (i.e: 11" X 8" X 2") and how many cooling rows does it have?

- How are the oil pump and oil cooler mounted back there and exactly where? Custom fabrication?

- What size AN fittings & Stainless Steel Lines were used? (-8AN? -10AN?) What size were the threads tapped into the cover and/or differential? (3/8" or 1/2"?)

- How are your feed and return lines physically routed from the bottom of differential (either from the differential cover or bottom of differential housing) and through the oil pump and into the oil cooler and back into the top of the the differential through the cover? In other words, is there enough room to run the lines over the top of the gas tank or was another method used?

Pictures would be really helpful too.:beer:Thanks!

 

[brkntrxn]

I'll have to look through my receipts when I get a chance to figure out the exact parts I used.

I drilled and tapped holes in my bumper support and JB Welded threaded rod to make four studs. Then I used some scrap steel to bend up a bracket to mount the cooler. It is a little off center since my external fuel pumps are dead center.

Since I have a custom fuel setup, the charcoal canister in the left rear quarter panel was not being used. I modified the tray and mounted my pump in that location. The diff is tapped on the bottom for supply and at the top for return. That way, the cooled oil is dumped directly on the ring gear.


Scrap brackets bent and painted:

Threaded rod studs in the bumper support (and painted):

90 degree elbow in the top of the diff, slightly off center and directly over the gear:

Supply tap on the bottom as well as a small hole for a temp sender:

Mounted on the rear:

Modified charcoal cannister tray and pump:

 

[VNEMUS]

Thanks for the response & pics brkntrxn!:beer:

Would you agree there is plenty of room to run the stainless steel lines from the bottom of differential case, up and around the sides of the top shelf of the stock gas tank, into the oil cooler, then into the oil pump and finally around the top shelf of the gas tank on the opposite side back to the top of the differential case?

The conscensus I seem to be getting is that -8AN stainless steel lines and -8AN fittings are sufficient.

One the decisions I'm struggling with is whether or not I absolutely should drill and tap the bottom of the differential case to draw the oil into the cooler vs. modifying the differential cover by welding in bungs for the feed and return lines. I see Maximum Motorsport's Kit drills and taps the bottom of the case, but modifies the cover for the return line. Obviously, there's more than one way to do this with similar end results. I'm interested in the pros/cons of both approaches and here's what I have so far:

For drilling and tapping the Differential Case for the AN fittings:
Pros: Location is best for drawing oil from the case to the cooler.
Cons: Fitting mounted to the bottom of the case is exposed and prone to damage in the event of an on/off track incident.

For modifying the Differential Cover for the AN fittings:
Pros: The oil draw AN fitting is somewhat protected from being a low point on the rear end in the event of an on/off track incident.
Cons: The oil draw fitting location is not the best, but acceptable, however, there is the potential for oil to be drawn in to the cooler and pump, which can affect the lubricating function and properties when the oil and air mixture is pumped back into the differential case.

Additional thoughts, comments or rationale for and against either method?

Any recommendations on whether the male-to-male AN fittings that tap into the differential case or cover be -8AN to 3/8" or -8AN to 1/2".

 

[LargeOrangeFont]

The exhaust will offer some protection to the fitting on the bottom of the diff. If you rip your exhaust off, you will probably have other more pressing concerns anyway. You will want to set up the lines such that the configuration lends itself best to cooling the diff. That is why you are doing this anyway right?

If you have cavitation issues in the pump, that is hard on the pump, and won't cool the diff as effectively.

 

[NJ 03Mach1]

I'm looking into this, (not planned for anytime soon) but how do you guy's know how much fluid to run?

 

[brkntrxn]

Craig,

You owe me a beer. I bought pretty much everything at BSR and below are the part numbers from my receipts. I cannot vouch for how many of the adapters I ended up using without crawling under the car. That will cost you another beer. The amount of swivels and adapters you need will depend on where you mount your equipment.

Cooler: BWN.001 -- small cooler 5.75x11x1.5
Pump: BSR.RP.3114 -- electric pump-rear end
45`: G00.823.8 -- #8 x 3/8 45` adapter
(2x) 90`: G00.822.8 -- #8 x 3/8 90` adapter
(2x) 90`: G00.822.8.8 -- #8 x 1/2 90` adapter
Straight: G00.816.8 -- #8 x 3/8 straight adapter
(5x): G00.1136.0108 -- #8 straight h/e swivel
8': AEQ.FBA.0800 -- #8 steel braided hose


Basically, I have a Flojet pump and a small B&M cooler with -8 lines to and from. The majority of your money will be spent on fittings and braided hose. I have had my setup on for a while, but only two track weekends (I blew an engine the day I installed it and the car sat for seven months while I drove the vert). However, those two track weekends were at CMP and VIR full. It definitely works.

BTW, if and when you do this, expect the pump to be loud. Seems to be that way for most people no matter which pump you use.


I also wrapped the tail pipes that in the area where they are near the diff:

Clamps: KEB.007 -- stainless steel clamps
Wrap: KEB.006 -- thermal header wrap (DEI header wrap)



edit: i before e, except after c

 

[brkntrxn]

I'm looking into this, (not planned for anytime soon) but how do you guy's know how much fluid to run?

LOL, good question.

Short answer: til it is full.

Long answer: This is what I did if I remember correctly. Disconnect the hose going from the bottom of the diff to the cooler as well as the add plug in the cover. Have someone hold that hose approximately the same height as the cooler. Put a hose into the cooler in the open connector. Turn on the pump and fill the cooler until oil runs out of the hose your buddy is holding or the fill plug. That should get you close.

I may have put a tad too much in mine as any time I do not turn on the cooler, I will get a burp or two out of the overflow tube on the top of the diff. Thinking about putting a catch can on it.

 

[brkntrxn]

Answers in yellow:

Thanks for the response & pics brkntrxn!:beer:

Would you agree there is plenty of room to run the stainless steel lines from the bottom of differential case, up and around the sides of the top shelf of the stock gas tank, into the oil cooler, then into the oil pump and finally around the top shelf of the gas tank on the opposite side back to the top of the differential case? Yes

The conscensus I seem to be getting is that -8AN stainless steel lines and -8AN fittings are sufficient. Yes

One the decisions I'm struggling with is whether or not I absolutely should drill and tap the bottom of the differential case to draw the oil into the cooler vs. modifying the differential cover by welding in bungs for the feed and return lines.

The diff is almost an inch thick at the top and bottom, that is far stronger than the 1/4 inch or less of the cover. Add to that I cannot weld and it made sense to me to tap it on the top and bottom where it would not only dump cool oil on the ring gear, but also drain the most oil from the bottom. Like stated above, if I rip that thing off, I have torn off way more than the 90` fitting as it sits right in between my tail pipes.

 

[brkntrxn]

BTW, don't ever touch the cooler as soon as you come off the track. Every single fin will leave a small narrow burn mark all the way across the palm of your hand. Go ahead, ask me how I know.

 

[NJ 03Mach1]

BTW, don't ever touch the cooler as soon as you come off the track. Every single fin will leave a small narrow burn mark all the way across the palm of your hand. Go ahead, ask me how I know.

Ok, I will!


How? :shrug:





:banana:

Thanks for the reply.

 

[VNEMUS]

Craig, You owe me a beer. I bought pretty much everything at BSR and below are the part numbers from my receipts. I cannot vouch for how many of the adapters I ended up using without crawling under the car. That will cost you another beer. The amount of swivels and adapters you need will depend on where you mount your equipment.

Kevin, I really appreciate your detailed responses and the extra effort you went through to confirm the part numbers and post the pictures.:bowdown: :beer:2X

Basically, I have a Flojet pump and a small B&M cooler with -8 lines to and from. BTW, if and when you do this, expect the pump to be loud. Seems to be that way for most people no matter which pump you use.

That is my understanding as well.;-)

The majority of your money will be spent on fittings and braided hose.

Yeah, you ain't kidding!!!

I also wrapped the tail pipes that in the area where they are near the diff.

I will definitely keep that in mind. Thanks for the suggestion!:rockon:

I think I've decided to drill and tap the differential case just like Maximum Motorsport's install instructions srecommend. This weekend I'm going to take a closer look at pump and cooler mouting locations and sketch out bracket design ideas and oil line routes and make a list of fittings I'll need to buy. I'll keep everyone posted.:thumbsup:

 

[brkntrxn]

No problem.


(VIR was MOST EXCELLENT today, btw. 65, partly cloudy and plenty of track time.)

 

[Maynor]

.. This weekend I'm going to take a closer look at pump and cooler mouting locations and sketch out bracket design ideas and oil line routes and make a list of fittings I'll need to buy. I'll keep everyone posted.:thumbsup:

Keep tabs on the pricing if you don't mind. Only reason I haven't gone this route is the cost of the "kits" out there. I'm not sure I can do it any cheaper than the kits but if you can, I may replicate it.

I put my money into safety this year (roll bar, hans, FIA seats, harnesses etc) and have a little left over if a custom cooler can be had for the remaining amount.

 

[VNEMUS]

Keep tabs on the pricing if you don't mind. Only reason I haven't gone this route is the cost of the "kits" out there. I'm not sure I can do it any cheaper than the kits but if you can, I may replicate it.

I basically priced out the indivdual parts of the $1349 Maximum Motorsport's Kit. Their Kit includes the following:

(1) Fluidyne Oil Cooler w/electric fan - $500
(1) Tilton Gear-oil Pump - $180
(1) Thermal Activation Switch - $50
(1) Electrical Relay - $10
(1) Relay Electrical Socket - $10
(2) In-line Fuse Holder - $10
(2) 10A Fuse - <$5
(4) 90 degree -8AN Fittings - $120
(5) Straight -8AN Fittings - $60
(1) 90 degree Swivel -8AN to NPT Fitting - $40
(2) 3/8" NPT to AN Adapter Fittings - $10
(1) NPT to Steel Adapter Fitting - $5
(1) -8AN Bulkhead Fitting - $7
(1) -8AN Bulkhead Nut - <$5
(2) AN Aluminum Crush Washers - <$5
(1) 15' Stainless Steel Braided Teflon Hose - $150 ($10/foot on avg.)
(1) Check Valve - $89
(1) Aluminized Heat Shielding - $10
(1) Silicon Heat Shielding - $10
(2) Hose Clamps, Rubber cushions for Pump & Cooler Mounts - $10

Important Notes about my finding above: These prices are what I researched online with various vendors and do not include shipping. These are for reference purposes only. Additional costs for fabrication, installation and parts not included such at an Oil Temp Gauge are not included.

My summary of findings:
A large chunk of the cost of MM's Kit is the Fluidyne Oil Cooler with Mounted Fan (approx. $500). It's an expensive piece. Is that the only Oil Cooler set-up for the job? I suppose that depends on the individual. Generally, what I've seen of heard people are running are Oil Coolers priced between $80 - $250 that do a perfectly fine job. There's $200 - $300 in savings right there.

Another large chunk of the cost of MM's Kit is the AN Fittings & Stainless Steel Braided Lines (approx. $250 for all the AN fittings and $150 for the SS Lines). MM kit provides extra fittings, more than what's needed. If you shop carefully, you can probably get all the fittings you need for <$100 and <$100 for about 10 feet of SS Lines. There's another $200 in savings.

MM's Kit recommends the use of a Check Value (approx. $89) and a Thermal Activation Switch (approx. $50). From what I gather some people use one or both, some use neither. There are benefits to using both, but not absolutely necessary parts. Potentially another $125 in savings.

The Oil Pump is $180 brand new pretty much wherever you look.

Misc. Parts / Differential Temp Gauge / Pod, wiring, etc. is going to cost about an additional $100, give or take a few bucks.

My final Conclusions:
A Differential Cooler Set-up that closely replicates the design and function of the more expensive kits on the market can be put together for about $700 - $800. I'm definitely moving forward with putting one together:thumbsup:

 

[Maynor]

Damn. Thank you. That even more detailed than I imagined.. Much obliged

John
Novi'd 99 Cobra

 

[Force4.6]

Awesome thread!!!! I had been wondering about a less costly way to get an IRS cooler, keep the info coming. :read:

 

[pkwest]

Sorry about the pictures. I just took these with the car on the ground. Tough to get far enough away for a good shot.
I used a mocal pump because it comes standard with viton diaphram/seals and can operate up to 300 degrees. The tilton comes standard with burna valves and seals and operate to 265 degrees. My pump is activated with a SPAL Thermal Fan Relay Kit with a 185 degree temperature switch mounted in the cover (It's like this one although I didn't get it here http://www.emspowered.com/storefront/index.php?main_page=product_info&products_id=166 ). See pic. The oil cooler is an afco but I forget the part number. I put all three bungs in the differential cover. The return is just above the filler plug and the suction is on the lower left side but is blocked by the Maximum motorsport differential mount in the pictures. Make sure to put some kind of sleeve on the braided hose because it can act like a saw over time and cut anything it contacts.

 

[99COBRA2881]

I wonder how much side exhaust would help bring down diff temps?

 

[Maynor]

PK, thanks for the pics. One concern... how do you manage airflow through radiator?

99 Cobra, yes, it will help.. Its just a pain to mount them if you have subframes and want to maintain some ground clearance.

 

[pkwest]

I plan on adding a fan if it is an issue. So far I don't think will be.