Transaxle oil cooler pumps Options

[pcar916]

... do you have empirical DATA so you KNOW your trans oil temp will run TOO HOT and that you MUST have an oil cooling system? You could find, as I did, that all that extra hardware is just NOT necessary.

I MUST. As I put in an earlier post temps on the track can never be less than 210 because that's the temp measured on the street in the early summer in relatively cool weather (for here). It's never going to be lower than that at the track but will certainly be higher, especially in the late summer. It's true I haven't measured it on the track, but this transaxle will never see hp and torque lower than this 3.6L delivers.

Since I'm building a filtration system anyway the extra cost is for a cooler, fan and the associated hose and fittings. I'm willing to go there knowing I'm squirting cooler oil on my R&P. I like 180-200 for an operating temp. If I could get the return oil to the 150 you see in your machine I'd be delighted. How are you measuring it?

Now, if I lived in Alaska we probably wouldn't be having this conversation... (IMG:style_emoticons/default/beerchug.gif)

[stewteral]

I'm planning on installing a trans cooler in my 1.8L race car if I ever resume racing at the National level.
I have no empirical data on which to base my decision - only experience.
What I do know is that shifting becomes more difficult the longer I'm on track.
To me, the most logical cause is transmission temperature.

Hey Racer Chris,

I'm running a 930 behind a 383 Chevy and simply installed a VDO sender in the bottom of the trans with the gauge in the dash. I started out with a trans cooler driven off the 1/2 shaft flange and after running Streets of Willow Springs
in 100+ abient got oil temps of 150F. So I removed all the hardware and found the oil temps only went up to 175F.

I DON'T NEED NO STINKIN' TRANS COOLER! (IMG:style_emoticons/default/smile.gif)

Best of luck,
Terry

[Randal]

I'm planning on installing a trans cooler in my 1.8L race car if I ever resume racing at the National level.
I have no empirical data on which to base my decision - only experience.
What I do know is that shifting becomes more difficult the longer I'm on track.
To me, the most logical cause is transmission temperature.

OK so what makes it shift harder is the higher oil temperature which cause metal to expand. Wonder if there is a rule of thumb for how much machined metal (like gears/shafts) expands for each XX degrees of temperature increase?

It would be hard to believe that the transmission fluid is breaking down, providing less lubricantion, resulting in harder shifting. (IMG:style_emoticons/default/huh.gif)

[J P Stein]

[

It would be hard to believe that the transmission fluid is breaking down, providing less lubricantion, resulting in harder shifting. (IMG:style_emoticons/default/huh.gif)

Why is that ( oil breakdown) hard to believe? Run your motor 50 deg over temp see what happens. At the only track day I ever ran (5 30 minute sessions-2 drivers), I could not believe how hot my trans got. I made the mistake of touching it......yowza!....that's enuff of that shit. (IMG:style_emoticons/default/blink.gif)

[Randal]

[

It would be hard to believe that the transmission fluid is breaking down, providing less lubricantion, resulting in harder shifting. (IMG:style_emoticons/default/huh.gif)

Why is that ( oil breakdown) hard to believe? Run your motor 50 deg over temp see what happens. At the only track day I ever ran (5 30 minute sessions-2 drivers), I could not believe how hot my trans got. I made the mistake of touching it......yowza!....that's enuff of that shit. (IMG:style_emoticons/default/blink.gif)

I guess because companies like SWEPCO have been around for some time, their products seem to work well and one would think they work well and have been tested at the highest temperature that could show up within a transmission. But then I don't have a clue on this one.

So is it the fluid losing capability or the metal expanding JP, or a combination of both? (IMG:style_emoticons/default/rolleyes.gif)

[ChrisFoley]

So is it the fluid losing capability or the metal expanding JP, or a combination of both? (IMG:style_emoticons/default/rolleyes.gif)

Even if the gear oil isn't breaking down, it loses viscosity as the temperature climbs.
Also, expansion of the case may affect alignment of components.
So its probably a combination.
I wouldn't want the temp to exceed 220F anyway.

[J P Stein]

I'm with Chris on this.

Porsche's syncro system of brake bands would seem particularly sensitive to the lube thinning out. The brake band/slider is basically metal to metal less the oil film.
I've seen several brake bands worn flat on the outside.....slider & dog teeth don't live long under these circumstances. Normal wear becomes catastrophic. There would seem to be an ideal temperature range for these bits to work against each other. I also think that heat expansion has little effect on shifting, but gear to gear may be another story......then the different rates of expansion between the Mag case & the steel gears/shafts may well come into play. Of course, when the oil thins, the gears come closer together (less oil film) generating more heat, then I can see the thing cascade on you. Get the sumbitch hot enough and you have no film.......the ring & pinion begin shedding metal and loose their finish surface....more heat....well, you get the idea....

I've torn down a couple trans that had reached the metal shedding point on the R & P......into the recycle bin with those. The pinion shafts were heat discolored about 1/4 of the way up the shaft. (IMG:style_emoticons/default/blink.gif) Since those trans were from low powered cars, I think they were run out of lube.....thus the neglect.

[john rogers]

For the temps question, I found with my trans temp gauge that until temps got to about 140 to 150 the trans seemed to be sluggish but then it was setup with tight clearances and ran a limited slip. Once temps got to over 275 or so the shifting got bulky and you had to shift slowly and very deliberate. This only happened at the street circuit races in Mexico where the straights were short and there was not enough time for some cooling and that is why I added an axial fan in the ducting line with a water mister from JC Whitney and Co that was actually meant to be an add on windshield washer reservoir and pump. The pump went to a garden mister and was switched with the fan and would drop trans temps by about 20 degrees when running which helped. The little bit of water lasted about 15 minutes which was sufficient for a sprint race. I was too old to do any of those enduros!!! The type of limited slip did not seem to make a difference as I used both a Guard and a "Q" which are different designs I think? I also had a pretty good shift setup with one of James' first Rennshifts and an aerospace coupler in place of the middle flex coupler.

It is the high RPM that gets the parts, especially the racing with high RPM motors and the revving with each shift, especially with engines that routinely rev to 8,000 RPM like my 2L six did. When I moved to a 2.8L six later on, the temps dropped slightly but only a little as the engine rarely went over 7,000 RPM. The HSR, VARA, HSR-West and other Porsche 2L class cars that bilders like Wayne Baker, Frank Beck and Jim Patriack on the west coast started using the pump and cooler setups after the 1st year and several transmission failures.Hope these ideas help some what?

[pcar916]

The simplest plumb... in, out, and a vent to the catch can.

[pcar916]

Finally time for an update. I forced myself off of the road because two weeks of consecutive 100+ temperatures reminded me that I hadn't installed this cooling system into the car. Attached are photos of the installation. I'm running the wire for the temperature sending unit after lunch today but everything works with no leaks.

Total system capacity worked out to be 3.75 quarts.

I have a 7in. Spal fan in the engine lid above the pump to help move more air into that side of the engine compartment. If the cooler can't move enough heat out of the fluid in the right rear fender well, I'll cut a hole into the engine compartment next to the cooler and force air out over the cooler. But I suspect the cooler will shed enough heat for me not to worry about it... unless it starts to bake my paint!






More below...

[pcar916]

The engine compartment plumbed and the temperature sending unit installed into my speedometer block-off plug.

[0396]

Thanks for sharing. Great looking set up

[brant]

Chris,


my race trans builder switched me over to heavier lube about 4 years ago...

I know I know everyone says not synthetic
I've been using them for 20 years though..

so we went from the mobil 1 75-90
over to the mobil 1 90-140

brant

[pcar916]

Thanks, I've done all I can to make sure it stands the test of time and vibration. I really hate rework due to poor engineering. So, the interim report.

After roughly 1000 miles of both spirited twisty Arkansas roads and 70 mph highway driving. I mean it... I never exceed the speed limit. Track report when I can get to one.

Temperature: average 150F - 170F (synthetic)
Pukeage: I expected some but it's as dry as a bone
Pump volume: ~ 2.5 gpm

Observation:
1. Works better than expected. Frankly, I'd rather it ran a little hotter.
2. Changing the fluid is a breeze.

I may relocate, or add another sending unit closer to the R&P/gear stack to test whether the box is hotter up there than at the back of the transaxle. I won't do this immediately... too many other things to do. But I'll update again with the temp-delta if there is one.

Note: About the sending unit.
To have one less place to leak fluid, I drilled the hole for the sending unit dry, so it doesn't contact the trans fluid directly. Then filled it with salt water as the sending unit was screwed in.

[naro914]

I am planning to do something similar. Been taking forever to get the time to do it, but finally got started last weekend.
I like the simple approach like this. My only concern is still when to have the pump turn on. manual is fine, as long as I remember to turn it on.... Some guys have told me that since the engine needs a warm up period anyway, just wait until the engine is warm, then flip the switch for the cooler pump when you head tot he track. While in THEORY that works, I just don't want to forget and end up overheating when I have a cooler installed but not running...

hmmm....

[pcar916]

This geared pump has no trouble at all pumping even cold fluid at more than 2 gpm so turning it on at the beginning of a run isn't a problem. As well, since it's a constant duty pump it won't matter how long it's on. That was a perk over the intermittent duty diaphragm pumps.

I considered installing a thermostat but I like simple systems.

One thing I am going to do is replace the 90 degree AN fitting on the pump outlet to a 180. It'll then run toward the right sidewall and be easier to batten down. The more I looked at this installation the more I didn't like a hose just going out into the engine compartment subject to vibration.

[naro914]

Guys,
For those using the Tilton pump, how noisy is it? We turned it on to test and it's REALLY loud. Not as loud as the engine, but loud enough to sound like there's something wrong with it.

I thought it was the mounting, but even holding it still against the rubber mounts doesn't change anything. I even thought that once it primed it would quiet down, nope. It's working fine, pumps the oil ver well, but just really loud.

thoughts??

[pcar916]

Ok, since I haven't seen an answer to this noisy-pump issue....

Considering how loud even rotary pumps are in a car with most or all of the sound deadening removed, I'd bet the pump is just fine. Every one of the diaphragm pumps I've used (some in fuel applications) is the same way.

I'd run it and listen for anything that changes. If I'm right about that car's usage you aren't running it more than two hours at a time, which is the Tilton time limit they state as the outside (per a Tilton vendor I talked to while deciding on a pump). On that point.

If anyone can point to documentation about that I'd like to actually see it in writing. Preferably tied to operating-temperature limits.

Have you learned anything different?

[moggy]

Ok, since I haven't seen an answer to this noisy-pump issue....

Considering how loud even rotary pumps are in a car with most or all of the sound deadening removed, I'd bet the pump is just fine. Every one of the diaphragm pumps I've used (some in fuel applications) is the same way.

I'd run it and listen for anything that changes. If I'm right about that car's usage you aren't running it more than two hours at a time, which is the Tilton time limit they state as the outside (per a Tilton vendor I talked to while deciding on a pump). On that point.

If anyone can point to documentation about that I'd like to actually see it in writing. Preferably tied to operating-temperature limits.

Have you learned anything different?

This has been a REALLY useful thread guys. Thanks.

I am just about to go down this route of cooler and spray bars on my gearbox after experiencing the same problems mentioned in this post, I.e. difficult shifting once the box starts to get real hot and now the synchro for second is needing replacement. I have the same causes - spirited driving (IMG:style_emoticons/default/happy11.gif) with lots of shifting due to the nature of rallying and the shorter gears (4th is now my 5th), powerful engine, Guard LSD, and to make matters a lot worse.... A skid plate. That last part basically stops any decent air flow cooling the box down and worse... Keeps the heat from the exhaust reflected back up (IMG:style_emoticons/default/blink.gif) cooking the gearbox.

Anyway.... My concern is regarding the choice of pump to go for. The Tilton says it should only be used For intermittent use, I think it was mentioned here, no more than 2 hours constant use. I was wondering if the RB Racing pump has the same limitation? 2 hours constant use is sorta ok but longer would be a lot better with my application. My plan is (was) to wire it up to the fuel pump 12v supply so it comes on with the ignition.

[pcar916]

I was wondering if the RB Racing pump has the same limitation? 2 hours constant use is sorta ok but longer would be a lot better with my application

The RB Racing pump is constant-duty so run it until the cows come home. It's interesting that Mocal now sells the RB Racing pump for about $25 more than RB does directly.