What is the stall speed on a DTT TC?

[Matt400]

Anyone perform or want to perform a stall speed on their 89% DTT TC?

I talked with a vendor and they say they don't rate it that way, I thought ok. . thats fine but I would still like to know what it is because it must stall somewhere.

 

[fox]

Here is a little explaining.

The Cummins makes so much torque off idle and is so easily modified for more, it is going to stall at different speeds for different mods.

My 89h and this set-up will be different with your truck.

Talk to DTT about this. They have the answer you need.

 

[bchesley]

I just had one installed two weeks ago. I cant give you an exact number but I would say at least 400 RPM less than factory. I also have some other DTT goodies inside so I dont know how much all the other parts attribute to it. Just curious or have a real need to know?



Brad

 

[Joe G.]

The stall speed will be different for various engines because of power. A more powerful engine will cause the stall speed to be higher.

 

[Matt400]

I realize more power can drive up stall speed and just figured I would take that into consideration based on the sig of whoever posted the stall.

I would call DTT but as I understand they don't sell parts and only will talk complete units. The vendor I spoke with said it is pushing it to get TC and is the only part they would let go of.



I am curious about it and as far as a need to know. . is so I can make some sort of informed upgrade decisions that also ties in with turbo selection for good spool while providing added cooling.



One thing the vendor said that concerned me is that one of these TC's will make the truck more doggy with the boxes turned off and that is the way I drive most of the time. His reasoning is the added fueling needed to drive the tight TC.



I don't want to start a transmission ware, just wanted to compare DTT's stall speed with manufactures that post theirs.

 

[mcoleman]

That is wrong. I installed my DTT 89% before the engine mods and the truck had loads more power and driveablity. Are you sure this is a DTT certified installer. I can't see any of them saying something that stupid. There are plenty of stock trucks running up and down the road everyday with an 89% and experiencing more power to the wheels as well as better fuel mileage.

 

[AK RAM]

I would call DTT but as I understand they don't sell parts and only will talk complete units.

I never had a problem getting the individual parts that I wanted from them. They can be a little picky if you try to buy just their converter. If you get their converter, they want you to buy their valve body and really push their update kit as well... . but not mandatory to make a purchase. There are reasons for that though, so ask the question and find out why when you talk to them.



Really can't speak to stall speeds.



My only advice would be to go tight. That is the only thing I have done to date that I would change if I had to do it again..... I wish I had gotten a tighter converter. All the advice I got was that I wouldn't like it when I hooked a trailer to it, but I feel I'm loosing lots of power until the converter locks and there is lots of room left for a tighter combination. Definitely skip the 89% and go with a 91%…you won’t regret it. If mine ever fries or I win the lottery (whichever occurs first), I will probably bolt up a Suncoast 91%.



As far as being doggy, it will a little, but you probably won’t notice it. Only when pulling extreme loads would you be able to tell the little bit you will loose, and probably not even then unless your really looking for it. Definitely won't notice it around town…it will feel even peppier in traffic on stock power, not wimpier. The problem is weight and rotating mass. You will have chunked the 35 lb stock converter and replaced it with a 60 to 70 lb (single v/s triple difference) converter. There is a lot of added weight in there that you must now turn before the truck even starts to move. It takes a little power to do that, but again not really enough to notice. I don't.

 

[paulb]

I would caution anyone trying to do a full stall test with one of our trucks. Especially one that is putting out a lot of torque. Some have done it and lived others... :{



It's not just the trans that has to live under a stall test but the rest of the drive train too. The test would probably have to be done in 4x4, at least with mine I know I can't hold the brakes hard enough to even build 10 psi of boost without the tires spinning. You take a chance on breaking anything from the trans case, to welding the ring and pinions together (or at least pitting them). I saw a stock input shaft break at ~15 psi (at least that's what he said he was at... ), when someone was trying to build boost to launch. The results of the test might be interesting, but it's not gonna happen with my truck!



Just my . 02 worth.



Paul

 

[tractorface]

I don't have a DTT but I have a tight aftermarket convertor none the less. As for the deal about the box turned off here is my expierience. My Raptor is on the blink, now I do have a HRVP44 but am on stock injectors. I can honestly say that you need not worry about the truck feeling doggy. You will get slightly more smoke ( on quick takeofs) and higher EGT's at takeoff from the added load but I am talking numbers well below being a "problem". The overall improvement of the better convertor will far outway that. I really don't tow so I can't comment on that but I was worried about the same thing and now know that was a waste of time. My truck is much quicker tahn it was even with the box not working. The transmission added a good bit and feels like a power mod.

 

[Dual EE]

My stall speed (trucks wants to go)is around 1400. I haven't check when it will actually stalls out. Things start binding up at 1400 though. The last dyno I was at, I made 755 ft# of tq at 1750 rpms (see readers rigs for for dyno sheet).



The DTT TC are tight. I actually noticed a slight lag in off the line power in the beginning (w/only a #6 plate). With the stock TC the engine would rev to around 22-2400 rpms with quick off the line starts. The DTT 89TC will start coming on at about 1750-1900 rpms. It starts putting power to the ground much faster. Now w/the 300's,181's, and a new fuel plate, the lag is diminished.

 

[tractorface]

Weight issues

I would love to see the weights of different convertors posted here. When I sent my stock convertor back to GB as a core I was surprised at how close it was to the triple disc I got from dave. The convertor was shipped UPS to save a few $$ on the transmission shipment. I may have had a little extra fluid in the OEM one I sent back but they were not that much different. I do have a Suncoast Flexplate and Highly reccomend some type of upgraded flexplate during your install. My OEM plate was bent which caused a serious vibration problem.

 

[Matt400]

Highly reccomend some type of upgraded flexplate during your install. My OEM plate was bent which caused a serious vibration problem.

Thats an interesting point was your OEM plate bent with an OEM TC or a aftermarket with or without billet cover?

 

[Matt400]

All the advice I got was that I wouldn't like it when I hooked a trailer to it, but I feel I'm loosing lots of power until the converter locks and there is lots of room left for a tighter combination.

Are you using the commander with your TC and if so what do you have lock up set to?

 

[tractorface]

My plate bent with the OEM transmission and convertor. It is part of the reason I upgraded. Did not know it was the plate until they had tried at least two convertors. It was not bent enough to see you had to measure the run out with tools. Caused a wicked vibration with the new convertor. not as bad with the OEM.

 

[Matt400]

Odd, you would think that with the robust billet cover on an aftermarket TC just bolting it to the flex plate would straighten out any runout it may have developed.

Are you sure it was bent or maybe had lost a weight?

 

[tractorface]

Nope it was bent. Mailed it to Dave Goerends so he could play with it. He was curious as well.