High power dsm tranny longevity.

Morpheus · Apr 2, 2009

I have a hard time believing the fluid temp will jump 100-150 degrees in a couple pulls, warrenting having an additional cooler.

The pump for the additional cooler could also aerate the fluid more which is actually worse for the gearsets and will cause pitting on the face of the tooth.

donniekak · Apr 2, 2009

Figuring the low end of drivetrain loss at 20%, 20% of 500 horsepower is a lot of heat.

Migsubishi · Apr 2, 2009

Black_ bullet said:
Yea Im thinking of using the Evo fluid too to give it a try,
and also thats crazy about the axle. So your breaking upgraded axles from a roll... Thats not right lol.

Go for it, should do fine.... about the axels, yea you have to realize that in boost my dyno graph goes almost vertical. The car hits hard as hell and has traction at full boost through almost every gear but the top of first. First only spins a little and sometimes but not all the time. When I raced that whipple nitrous cobra from a roll I broke traction for a little when brake boosting building 24psi. I litterally jumped away from him real hard by 2 cars and then pulled more in 3rd. I think thats what did it, my car digs hard from a roll too and after that is when it happened.

wheelhop said:
Ebrake preloading saves first gear at least.

I'm planning to use the dsmlink nitrous controls and rigging up the egr solenoid valve to bypass the MBC until my choice of rpm and throttle conditions are met. Pick an rpm in the nitrous control that will be just above the rpm you'll see when shifting from stock redline to the next gear (especially third). And that should end up above your launching rpm as well. It could soften the load shock. In addition to doing that, you can program in a certain MPH so that your high boost setting will never be seen in 1st gear if you're getting wheel spin off the line. Or program it at a high enough mph so that your 1st gear will be rolling faster before you see that high boost setting. Jack of Jacks Transmissions says that wheelspin is a key contributor to killing drivetrain components. It sends many "microshocks" through the gears and shafts.

Stock AWD gear ratios:

- Shifting at 7500rpms from 2nd to 3rd puts you at about 5000rpms. Shifting at 7500rpms from 3rd to 4th puts you at 5500rpms. 3rd goes before 4th usually.
- 2nd gear seams to hold up fairly well. 1st gear ends 34mph at 7500rpms red line. Most people get better results by shifting a little early out of 1st.

Based on the above, have the nitrous controls set for 5600. 3rd will have about 600rpms of low boost as soon as you shift into it from 2nd. And 4th will have about 100rpms of low boost. This will effectively preload the drivetrain before the high torque can occur in all the gears, even 1st . You could prevent having to do the ebrake preload in 1st that requires a lot of clutch slipping for a car with enough torque to blow the traction if the clutch were dumped. Set your throttle postition for a point where you want this to be active. Like at above 50% TPS, any thing below that and you're probably not racing anyway. Nor will the torque likely be high enough to damage at that throttle position. . . For many of us. No need to actually look for a laggy turbo. Make the turbo laggy when you want to.

I want to try the above this season.

Alot of truth in that!

Morpheus said:
I have a hard time believing the fluid temp will jump 100-150 degrees in a couple pulls, warrenting having an additional cooler.

The pump for the additional cooler could also aerate the fluid more which is actually worse for the gearsets and will cause pitting on the face of the tooth.

From Sheps mouth to my ear and I take nothing he says in jest..... it works man

wheelhop · Apr 2, 2009

donniekak said:
Figuring the low end of drivetrain loss at 20%, 20% of 500 horsepower is a lot of heat.

I've NEVER believed the percentage drivetrain loss is linear as horsepower goes up. Think about it. 20% of 500whp is 100 HP. At stock, there's probably about 30whp lost through the AWD drivetrain mass. That leaves 70whp in more heat above stock? That's 52,200watts of heat energy over the heat produced with stock power!!! Though I do believe that a tranny heats up quick even after just one pull with decent power running through it, my arc welder cant do 1/10th of that 52,200 watts.

donniekak, I'm not sure what the best oil is. This is the first I've heard of someone who actually used royal purple and had issues. I probably wont drive my car like it's someone elses all the time (but I do track my car), but I want to know that I could. Thanks for giving your experience. NO one whos used The mitsu oil has said any thing negative at all. I think I might try that too.

Morpheus · Apr 3, 2009

wheelhop said:
I've NEVER believed the percentage drivetrain loss is linear as horsepower goes up. Think about it. 20% of 500whp is 100 HP. At stock, there's probably about 30whp lost through the AWD drivetrain mass. That leaves 70whp in more heat above stock? That's 52,200watts of heat energy over the heat produced with stock power!!! Though I do believe that a tranny heats up quick even after just one pull with decent power running through it, my arc welder cant do 1/10th of that 52,200 watts.

You can't say 100% of that goes to heat in the trans oil. You've got losses from the trans, axles, bearings, tires.

Morpheus · Apr 3, 2009

Migsubishi said:
From Sheps mouth to my ear and I take nothing he says in jest..... it works man

I'm not arguing that the concept doesn't work. My point is, the true neccessity to have it. Sure, possibly at Shep's HP levels, he might need it, afterall he's likey got another 500-600hp on you. I'd argue the benefit is more likely the larger volume of fluid available to trans.

I'd be interested in see the temp traces of the trans fluid. Unless you're doing 1-5 mile WOT's, I just don't think it's neccessary. Hell, a 610 ft-lb diesel pulling a 20K trailer on a 6% grade won't put 100 degree into the diff oil in 10 secs. You're talking 5-15 minutes. Even then, pull level ground, it cools back off.

Anyone ever thought of doing any aero mods to provide fresh are to the trans? Afterall, it's a big heatsink.

Migsubishi · Apr 3, 2009

Morpheus said:
I'm not arguing that the concept doesn't work. My point is, the true neccessity to have it. Sure, possibly at Shep's HP levels, he might need it, afterall he's likey got another 500-600hp on you. I'd argue the benefit is more likely the larger volume of fluid available to trans.

I'd be interested in see the temp traces of the trans fluid. Unless you're doing 1-5 mile WOT's, I just don't think it's neccessary. Hell, a 610 ft-lb diesel pulling a 20K trailer on a 6% grade won't put 100 degree into the diff oil in 10 secs. You're talking 5-15 minutes. Even then, pull level ground, it cools back off.

Anyone ever thought of doing any aero mods to provide fresh are to the trans? Afterall, it's a big heatsink.

What I think your missing is how hot the cast iron engine block is. Not sudden heat from a pull but over all heat that a pull can add to. A tranny cooler isn't just for sudden pulls, its for any prolong duration that the engine is putting heat through the trans. Our cars run in temps between 180 - 210 degrees, now that temp is right at the core of the block. Now what is at the core of the block, the crank, and what is bolted to the crank, flywheel,clutch and through them the tranny. Now that input shaft takes the brunt of the heat and distributes it through out the rest of all metal that comes in contact with it. Now lets say 100 degrees of engine heat is already in the trans, now add hard stress and fatigue on top of that. Now picture this, when there is no trans cooler what happens to the oil, it stays in there boiling the gears.

Another smart thing to do aswell is when you just get done racing or doing a hard pull you should drive around a little to keep the fluids in the trans moving and cooling. When you stop and let it rest all that heat in the fluid just boils the gear clusters.

Tranny cooler ftw regardless of hp.

Morpheus · Apr 3, 2009

Migsubishi said:
What I think your missing is how hot the cast iron engine block is. Not sudden heat from a pull but over all heat that a pull can add to. A tranny cooler isn't just for sudden pulls, its for any prolong duration that the engine is putting heat through the trans. Our cars run in temps between 180 - 210 degrees, now that temp is right at the core of the block. Now what is at the core of the block, the crank, and what is bolted to the crank, flywheel,clutch and through them the tranny. Now that input shaft takes the brunt of the heat and distributes it through out the rest of all metal that comes in contact with it. Now lets say 100 degrees of engine heat is already in the trans, now add hard stress and fatigue on top of that. Now picture this, when there is no trans cooler what happens to the oil, it stays in there boiling the gears.

Another smart thing to do aswell is when you just get done racing or doing a hard pull you should drive around a little to keep the fluids in the trans moving and cooling. When you stop and let it rest all that heat in the fluid just boils the gear clusters.

I work for an OEM. I also dyno test powertrains daily. In addition, I've also done vehicle testing on Davis dam, Baker Grade, and in Death valley in the middle of July and August. I realize the temps where the engine runs. However, your actual trans temp at speed (say 55) isn't going to be 180 or 200 degrees.

A trans cooler, for the average DSM enthusiast, isn't going to do much if anything. An auto putting 600-800hp through it might heat the trans by 100 degrees for a pull, but it's an auto with a torque convertor. Convertors create ALOT of heat.

Migsubishi said:
Tranny cooler ftw regardless of hp.

I strongly disagree with that. There is a cross over point between where it will won't help. Where? I can't tell you exactly, either can anyone else.

Do you have any temp data to prove it help your situation? At the point you added the cooler, what else did you change/modify?

wheelhop · Apr 4, 2009

Morpheus said:
You can't say 100% of that goes to heat in the trans oil. You've got losses from the trans, axles, bearings, tires.

Still enough heat to melt your mom into a 5 chick orgy

. I wish my welder could do better. Either the heat is't there and the crank hp is lower. Or the heat is there and the crank hp is higher. I'm not disputing you at all. But alot of heat is being discussed.

donniekak · Apr 4, 2009

I live in arizona, the ambient temp 2 feet off of the pavement is already 130+. I've though about this before, but as others have mentioned i worry more about airation of the oil from pumping. The gear oil in my stealth would come out looking like i burnt french fries in it, so i know it gets real hot. I've turned royal purple black in less than 10,000 miles. So the heat is there, no doubt.

Morpheus · Apr 4, 2009

I can't tell you what vehicle this is from other than it's many years old, a turbo diesel with a GCW north of 23K, putting down north of 600 ft-lbs on Baker Grade on the I 15 in CA. Please note the length of time to acheive 100 degree increase in temp. This is rear diff temp running around 2 quarts of oil. DSM trans runs around , what 2.75 quarts or so. Axle is steel and will retain heat better, trans will cool better. Thus, my reasoning why I'm raising questions.

Migsubishi · Apr 4, 2009

Morpheus said:
I work for an OEM. I also dyno test powertrains daily. In addition, I've also done vehicle testing on Davis dam, Baker Grade, and in Death valley in the middle of July and August. I realize the temps where the engine runs. However, your actual trans temp at speed (say 55) isn't going to be 180 or 200 degrees.

A trans cooler, for the average DSM enthusiast, isn't going to do much if anything. An auto putting 600-800hp through it might heat the trans by 100 degrees for a pull, but it's an auto with a torque convertor. Convertors create ALOT of heat.

I strongly disagree with that. There is a cross over point between where it will won't help. Where? I can't tell you exactly, either can anyone else.

Do you have any temp data to prove it help your situation? At the point you added the cooler, what else did you change/modify?

Thats great you have done so much, but I see we are not going to agree on any of this as I still agree to disagree with most of what you said.

An auto trans has a cooler running on it consistantly, not just when you floor it. Now how do you know what the temps are in every transmission and or engine. Lets say your engine is 7.8:1 compression and runs cooler than my 10.1:1 compression engine... is there a heat difference there to be transfered through all connecting metal parts? Yes

Auto transmissions cool all the time as should we do with our tansmissions, now lets think about this for a minute. The trans might not see 200 degrees but do you think at 120-150 with constant stress a fatigue would not benifit from some temperature relief. TRE, Shep racing,Rau, etc all can''t be wrong...

Morpheus · Apr 4, 2009

Migsubishi said:
Auto transmissions cool all the time as should we do with our tansmissions, now lets think about this for a minute. The trans might not see 200 degrees but do you think at 120-150 with constant stress a fatigue would not benifit from some temperature relief. TRE, Shep racing,Rau, etc all can''t be wrong...

Go back to what Wheelhop mentioned. The preload. So, joe average DSMer that makes 200-400 (or whatever hp), that on a pull puts 1/4 (or whatever percentage) of the heat that you might or a lesser percentage in comparison to Shep/Rau (ie 1000/1400hp), puts a cooler on his trans. Now, instead of running near the normal operating temperature of say 150 degree, now runs at 100 degrees or 80 degrees.

How does that affect preload?
How about viscosity of the fluid?
Are the bearings that are splash and gravity fed, going to get the correct flow of fluid to them?

slow talon · Apr 6, 2009

I think aerating the fluid is bs, 1 What the hell do you think the actual gearset or even better the front diff is doing to the fluid while spinning at a high rate of speed and 2 if the cooler pump is pumpng into a cooler that will help this so called aeration.

Im going to test this pumping system on my trans that will be set up on the preloading tight side of the scale and see what happens to it. Our transmissions are just plan junk but i sure as hell cant afford a ppg dogbox.

Black_ bullet · Apr 8, 2009

+1 ^

And yea so now I have re convinced myself to go with the evo3 gears, since it is proven that they are indeed stronger. But Iam only doing 3rd and 4th. Think I will also test out the tranny cooler thing as well. With that done to the tranny if it can hold up 400 ish ft/lbs of torque reliably with occasionally passes at the strip then Ill be content...

Morpheus · Apr 8, 2009

slow talon said:
I think aerating the fluid is bs, 1 What the hell do you think the actual gearset or even better the front diff is doing to the fluid while spinning at a high rate of speed and 2 if the cooler pump is pumpng into a cooler that will help this so called aeration.

Sure the gearsets are aerating it. Explain how a cooler gets rid of aeration.

slow talon · Apr 9, 2009

I doesnt get rid of it but helps smooth the fluid out abit to form larger bubbles and not the possible foam that could accur thus getting rid of the air quicker.

wheelhop · Apr 10, 2009

Time gets rid of aeration. A cooler affords more time to the fluid. And also raises the required fluid volume which helps that time do a better job. How is the aeration by a tranny pump not canceled by the higher fluid volume and longer time between being aerated?

I have to agree with the trans cooler. It does several things. Mainly, it has been proven to help. So I'm not understanding the arguelmet about joe dsmer not needing it. Whoe here doesn't push their dsmtranny beyond what the factory intended.

wheelhop · Apr 10, 2009

Besides, with respect to a tranny oil pump aeration only really can be measured significantly when cavitation occurs since the system is completely primed. There is no air to fill holes when the forces moving the fluid are in check with the forces of the atmosphere. We're not talking about overworking a pump or the fluid it moves. We're talking about uniform movement to provide cooling that would otherwise not occur. After all it is simple: heat kills transmissions.

Lastly, no one using a tranny cooler has remarked on pitting of gearteeth to support that assumption.

vinnybean · Apr 24, 2009

What else needs to be done when switching to EVO 3rd and 4th gears. TRE sells a double syncro evo 3rd and 4th kit for like 425. Anything else needed?

High power dsm tranny longevity.

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