Transmission Coolers

[charles charlie]

Yes they do. The Mocal unit is a diaphragm type yet Mocal have a gear driven unit which I could only find available in the US.

This is part of the reason why I bought the SSP version as their pump is this Mocal gear driven one.

[Armanc1]

Originally Posted by gtrsam

Does both the Forge and GTC/SVM kit use a diafragm pump !? then its a fail would never put that on my car....

What is so bad about diaphraghm pump for the oil cooler? Interested as Im on the market for the oil cooler.

[charles charlie]

The main issue with diaphragm pumps is the theoretical weakness of the diaphragm itself as it becomes weaker under extended usage. As temp rises, the risk of failure of the diaphragm increases as the rubber type material will fatigue over time. Many people would suggest that a diaphragm pump isnt suitable for pumping hot oil for an extended time.

Google "mocal diaphragm pump failure" for a taste of this issue.

Gear pumps shouldnt have this problem as the gears used to move the fluid are more temp resistant.

One way of reducing this potential risk to the diaphragm is to place the pump after the cooler of course.

I am far from an expert in pump types and failures, but I certainly feel more comfortable using a gear pump rather than a diaphragm type and the research I've done seems to show that many agree with this.

That said, there is no evidence of Mocal diaphragm pumps failing on Forge cooler kits and time will tell whether the problem is theoretical rather than actual.

I should also add that I spoke with a contact who works in a motorsport setting and he said they always use gear pumps for moving hot trans fluid or engine oil for the reasons I stated above. Had me sold.

[Armanc1]

Originally Posted by charles charlie

The main issue with diaphragm pumps is the theoretical weakness of the diaphragm itself as it becomes weaker under extended usage. As temp rises, the risk of failure of the diaphragm increases as the rubber type material will fatigue over time. Many people would suggest that a diaphragm pump isnt suitable for pumping hot oil for an extended time.

Google "mocal diaphragm pump failure" for a taste of this issue.

Gear pumps shouldnt have this problem as the gears used to move the fluid are more temp resistant.

One way of reducing this potential risk to the diaphragm is to place the pump after the cooler of course.

I am far from an expert in pump types and failures, but I certainly feel more comfortable using a gear pump rather than a diaphragm type and the research I've done seems to show that many agree with this.

That said, there is no evidence of Mocal diaphragm pumps failing on Forge cooler kits and time will tell whether the problem is theoretical rather than actual.

I should also add that I spoke with a contact who works in a motorsport setting and he said they always use gear pumps for moving hot trans fluid or engine oil for the reasons I stated above. Had me sold.

Thanks! I read on Nagtroc that you (I believe it was you ) who used the SSP cooler kit but not the sump... Was the price the only issue to use a mix of parts and not a full SSP kit? Im desperate as I keep hitting 110+ degrees on our local track after some 4 laps...

[charles charlie]

Yes that was me over on NAGTROC.

The SSP pan was over £1000, Japspeed's was £314 delivered and allowed me to add a temp switch.

Big cost difference without any additional gain in getting the SSP one.

I checked beforehand that the AN fittings were the same so that install wouldnt require too much messing around with adaptors etc and the Japspeed one came with all the bits I needed except new bolts and gasket.

OEM gasket cost me £30 or so, and SSP supplied new shiny bolts with their kit (even though I didnt get their sump).

I know many people like a whole kit in a box but for me part of the fun is putting stuff together.

I also bought decent double core wiring and sleeving so the garage fitting it wouldnt have to find anything. Final addition was a decent looking switch.

I cant say that my install is working completely to cool the trans as the only real test is on track, but that is coming soon.

I need to get some injectors and new intakes fitted first, followed by Ben mapping my car again then it's ready to go.

[Armanc1]

Thanks for the writeup! Was just wondering if you were considering also the GTC cooler which is about the same idea, just the oil radiator is smaller and placed under the lefthand side headlight and has one fan instead of 2.

[gtrsam]

Here is the bad part
"2 UK gals/10 litres per minute with 7 amps current draw.
Temperature constant use up to 130oC, intermittent up to 150oC. "
Electric oil pumps

Originally Posted by Armanc1

What is so bad about diaphraghm pump for the oil cooler? Interested as Im on the market for the oil cooler.

[David.Yu]

Originally Posted by gtrsam

Here is the bad part
"2 UK gals/10 litres per minute with 7 amps current draw.
Temperature constant use up to 130oC, intermittent up to 150oC. "
Electric oil pumps

What's bad about that? Highest I've seen on track with my cooler had been 115C. You're never going to get it to be constantly at 130C with the cooler on.

[gtrsam]

Pls see post 10# Forge Motorsport transmission cooler - NAGTROC - The Nissan GT-R Owners Club

Originally Posted by David.Yu

What's bad about that? Highest I've seen on track with my cooler had been 115C. You're never going to get it to be constantly at 130C with the cooler on.

[charles charlie]

Originally Posted by David.Yu

What's bad about that? Highest I've seen on track with my cooler had been 115C. You're never going to get it to be constantly at 130C with the cooler on.

More a theoretical issue in this case David.

Generally, the diaphragms are the weak point in these type of pumps and longevity is affected directly by exposure to temperature and pressure.

Pressure is less of an issue with trans fluid coolers but the higher the running temp, the more flexible the rubber type diaphragm gets and thus over time there is the potential for failure given the rapid in/out movement of the diaphragm.

The potential for fatigue and failure will be a combo of how much the pump is used at what temps.

Gear pumps have no such issue but as yet, we have seen no failures of these pumps so the risk is a theoretical one.

I chose a gear type and mounted it in a cooler position as I had misgivings over Forge's placement of the pump very close to the high radiant temps given off by the downpipes.

Again all theoretical and may never show themselves in reality. Only time will tell.

[Chubby]

Originally Posted by David.Yu

What's bad about that? Highest I've seen on track with my cooler had been 115C. You're never going to get it to be constantly at 130C with the cooler on.

I have had it over 130C with a cooler on track - it all goes red!!

Rich.

[David.Yu]

Originally Posted by Chubby

I have had it over 130C with a cooler on track - it all goes red!!

Rich.

Is that with the fan assisted SVM cooler? I think it's safe to say nobody drives as hard on a track day as you do racing!

But as the specs for that Mocal pump say, it's ok for it to go to 130 occasionally. Having said that, provided the size of the unit is not completely different, I can see why a diaphragm pump could not be simply replaced with a gear pump.
And failure of the pump does not lead instantly to gearbox failure, it will just get hotter and you bring the car in.

[Guy]

Originally Posted by Chubby

I have had it over 130C with a cooler on track - it all goes red!!

Rich.

Not surprising if you're running 700bhp+. The amount of heat energy the transmission creates is closely linked to power passed through the gearbox.

Thats still a lot better than stock, as I was able to get my stock '09 to 140c easily on track.

[Chubby]

Originally Posted by Guy

Not surprising if you're running 700bhp+. The amount of heat energy the transmission creates is closely linked to power passed through the gearbox.

Thats still a lot better than stock, as I was able to get my stock '09 to 140c easily on track.

I agree with all above - and it was a very hot day - if we can remember those..

No I do not have a fan assisted transmission oil cooler.

I do have a fan assisted engine oil cooler SVM upgrade.

The fan only helps when you slow down / stop - if you get off the power and drive quickly but not 'balls oot' the temps fall very quickly.

Am now looking into fitting a rear diff cooler, as hopefully everyone is aware that this is bolted on to the gearbox and also contributes to the increase in oil / transmissions temps..

Rich.

[David.Yu]

Originally Posted by Chubby

I agree with all above - and it was a very hot day - if we can remember those..

No I do not have a fan assisted transmission oil cooler.

I do have a fan assisted engine oil cooler SVM upgrade.

The fan only helps when you slow down / stop - if you get off the power and drive quickly but not 'balls oot' the temps fall very quickly.

Am now looking into fitting a rear diff cooler, as hopefully everyone is aware that this is bolted on to the gearbox and also contributes to the increase in oil / transmissions temps..

Rich.

Yeah a rear diff cooler should help. It's the first thing the Nismo race cars do.
What make of trans cooler do you use?
130C is no problem if you change the fluid after every race. With Willall fluid you could probably not even need to do that.