Lower stall speed TC than Suncoast?

sailwa66 · **Joined:** Mon May 14, 2012 9:57 am **Posts:** 32

I've had a Suncoast TC in my 05 for about a year now, and at time of ordering, asked them to set the stall speed as low as possible/practical. However, I was really disappointed at the difference in stall speed between the Suncoast and a the stock TC it replaced. The difference seems almost imperceptible to me; maybe 100rpm less?

I called Suncoast, and while they were very helpful, going as far as letting me talk directly to the guy that builds the TCs, the consensus was that it was built as 'tight' as they can, which is roughly 300rpm lower than stock.

Well... it's still way too loose. It puts the 'slush' in 'slushbox'. :roll:

I'd love to throw a NSG370 6-speed in there, but the 0.84:1 top gear is significantly shorter than the 0.67:1 of the slushbox, so that's not an option.

Does anyone know if there is a vendor which builds a TC with a substantially lower stall?

pwrwagn · **Joined:** Mon Jul 22, 2013 2:40 am **Posts:** 192

sailwa66 wrote:

I've had a Suncoast TC in my 05 for about a year now, and at time of ordering, asked them to set the stall speed as low as possible/practical. However, I was really disappointed at the difference in stall speed between the Suncoast and a the stock TC it replaced. The difference seems almost imperceptible to me; maybe 100rpm less?

I called Suncoast, and while they were very helpful, going as far as letting me talk directly to the guy that builds the TCs, the consensus was that it was built as 'tight' as they can, which is roughly 300rpm lower than stock.

Well... it's still way too loose. It puts the 'slush' in 'slushbox'. :roll:

I'd love to throw a NSG370 6-speed in there, but the 0.84:1 top gear is significantly shorter than the 0.67:1 of the slushbox, so that's not an option.

Does anyone know if there is a vendor which builds a TC with a substantially lower stall?

I have the suncoast as well, and no, it's not hugely lower, but after driving it around a while, I've come to appreciate that it makes a solid difference in how it drives. Since I had no idea what TC was in the rig when I got it, and the price wasn't much different, I went for the Suncoast. What I've noticed, is that under cruise conditions, it seems to lower the "mild acceleration" point from about 2100 to about 1750-1850 @ 45-50 mph.

It wasn't the massive change I had for my '93 dodge W/Cummins, but it also would not have been appropriate.

Auberon · **Posted:** Mon Oct 28, 2013 9:28 am

This is my concern also.
I plan on a different torque converter. As I am metricated, plugged the GDE numbers into a spreadsheet and found some interesting things.
When plotted to remove the faked bumps by smoothing the curve (you know good graphing techniques and the like) I get the following numbers:
The benefit of the metric numbers is they tend to spread the curves out a bit giving something like:
HOT TUNE: is a sharp rise to a fairly flat line between 1300 rpm & it then begins to taper off slowly after 2400 rpm - holds about (average in this range) 500 Nm fairly constantly. Torque with this tune seems fairly constant at this level of 500 Nm in the rev range quoted
ECO TUNE: is a gentle rise to about 1600 rpm where the curve begins to flatten out to the point where it begins to drop at 2600 rpm - holds about (average in this range) 450 - 460 Nm on a fairly flat line to about 2600 rpm same comment as above

STOCK TUNE: a more gentle gradient again that is overall much flatter peaking at about 410 Nm again averaged for this range with a significant flattening at 1600 rpm and then declining at 2500 rpm within this range of 400 - 410 Nm.

I agree with the search for a torque converter but I haven't been able to find one either.
Thanks for putting up the question.

pwrwagn · **Joined:** Mon Jul 22, 2013 2:40 am **Posts:** 192

Unless you can find a way to lower the actual idle speed, you probably don't want a lower stall converter.

It pulls a little more than optimal when stopped, and going to lower stall would probably cause you to really use up your brakes fast, not to mention make heat and use more fuel when stopped.

There's a characteristic, I forget the name, which is the "quickness" (amount of change in speed) where the converter goes from loose coupling to tight, and it can be altered a little, but if memory serves, it decreases the torque multiplication a bit. So, I think we're kinda stuck where it is, unless you want a very specific purpose met.

Franko · **Posted:** Mon Oct 28, 2013 11:21 am

What about the Euro Torque converter, would that possible be the solution. I'v heard good things about that one.

Auberon · **Posted:** Tue Oct 29, 2013 7:25 am

Indeed - have considered this one but can't seem to lay my eyes over useful figures for it.
Hang the tweaks of response time how on this green earth do you select a TC when you cannot find the performance data that you need to see how it marries to your rig. That is also affected by the friction materials employed on clutch packs and the response time of the valve body.
There is no dark science in this - it should all be able to be done on the REAL known performance numbers.
This is purely an engineering excercise based on data - to keep you looped into the original marques and find a better job.

We can all determine the ideal selection parameters for our needs to best match the TC to the 545REF and this rev range with our turbo - but where the heck do you find that data?
Any clues would be appreciated VERY much.

I don't deal in opinion and personal views. I need real numbers to match with what I have collected on this engine/tranny/turbo combo. I fail to be convinced there is only one TC that will fit.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The mopar euro TC is exactly the same as the stock one, except for stiffer lockup clutch springs. The rating goes from 300 ftlb up to 400 ftlb. The stall speed is the same as stock. Stall speed is not the best number for rating converters since the stall is proportional to the horsepower output from the engine. Example: stock CRD makes 160 hp and brake torque would give a stall lets say around 2300rpm, with a tune you would have about 185hp and brake torque would then show a higher stall speed maybe around 2500rpm.

Manufacturers use the k-factor instead of stall since this rules out the input power. The mopar converter has a k-factor of 150.

Auberon · **Posted:** Tue Oct 29, 2013 11:36 pm

That's a really valid comment from the guys at GDE (as you would, of course, expect) but most TC makers seem reluctant to disclose k-factors when you shop around.

"They" (being the TC makers) want to do the selection with an absolutely minimal input from the customer. When parting with this kind of money especially when you may be shipping it across the world with heddy shipping involved full disclosure of data would be a nice thing [u]before[/u] ordering.

So far they ask HD or stock equivalent for the most part and that seems to be all you get. That may be heavier springs but not necessarily.

I like to know what I'm paying for.

Auberon · **Posted:** Sat Nov 02, 2013 9:00 am

I hope I have this right:
Data for input into one of the simple formulae often used would be (for the GDE HOT TUNE)
Torque = 350 ft lb
K factor = 150 (based on the data in this thread)

rpm = K x sq root torque
= 150 x root 350
= 150 x 18.7
= 2800
This would therefore be indicative of the stall speed of the euro TC.
Gives ball park figures but as stated in the thread you need to consider many other factors when selecting a TC.

Of course, there are other formulae out there to determine K factors I just used a simple algorithm I am aware of.

MOST IMPORTANTLY (not shouting just emphasizing):
Seems this is one area where compromise is necessary whereby one needs to use a unit known to be compatible rather than here-say from some unknown individual pushing their personal ideas and rather accept what GDE say as sound.
They seem to have no barrow to push in this regard and are just honestly offering the best of information they have.
Works for me. Now I just have to find one at reasonable cost (with freight).

WWDiesel · **Posted:** Sat Nov 02, 2013 10:53 am

Auberon wrote:

I don't deal in opinion and personal views. I need real numbers to match with what I have collected on this engine/tranny/turbo combo. I fail to be convinced there is only one TC that will fit.

I totally agree with Auberon; What would be real nice for KJ future TC purchasers would be a side by side comparison of real figures between the European TC and the Suncoast TC. I would like to view all the real world specifications that the manufactures can provide without giving up any proprietary data. Stall speed is OK, although I think on a diesel it is not that important as compared to a gas engine. To me, the most important data would be the amount of surface or friction area for the lockup clutch along with the thickness of the clutch plate and the thickness of the metal area in the TC where it locks against. Secondly the pressure or force applied by the springs against the lockup clutch when in lockup mode. :roll:

I know from building up my Dodge Cummins and going through three TC's before installing a Suncoast that these factors are what really matters when trying to hold high rotational force (torque) in a diesel in lockup. Factors to consider: lockup clutch slippage or chatter wears the clutch lining and at the same time heats the metal contact area in the TC and causes it to warp. When my first two TC's were replaced; both of them on the back side of the TC (flywheel side) had blue spots on the metal from warpage and overheating caused by slipping. These two problems together as it happens increases the rate of chatter or slippage exponentially until it slips anytime high torque is applied while in lockup and will eventually lead to total failure. :dead:

The Suncoast TC weighed about 1 ½ times as much as either of the previous TC’s, this is due to the much thicker billet steel flywheel area to prevent any warpage.

I can not speak as to the European TC specifications although I can say with certainty that the Suncoast TC in my Dodge Cummins has held everything I have thrown at it so far. :BANANA:

I learned from my Dodge experience that the second TC was costly learning and I do not wish to repeat that on my KJ. If buying the higher priced Suncoast will ensure no costly third time, then the money is well spent considering labor costs and / or down time. There again, if someone can provide real data on the European TC for comparison sake, I would feel much more comfortable taking the European TC route. :2cents:

Auberon · **Posted:** Sat Nov 02, 2013 11:54 pm

So very true VWDiesel. Stall speed means very little to us with the diesel unless you are running track :ROTFL:

That's why I ran the numbers to illustrate.
Not my primary parameter for performance. Mine are more along the lines of those you are driving at.

Take an OAD just for example for discussion purposes. We can compare the absolute merits of the Goodyear and Gates brands and others and then make a really informed decision on what we choose to install. These are only a max $100 part for the most part. I'm ignoring freight here as that is usually the killer but it puts more emphasis on making the right choice outright.

With the TC I want to compare apples with the same kind of apples.
Hate being stuck with one source of data (not detracting at all from what the chaps at GDE say) but I like to have input to what I spend my hard-earned on. It's too hard to come by in my situation.

Why can't we do this with our TC - a component that can stuff up your whole tranny if it's inadequate.
This is just BS. on the part of suppliers and keeps us in the dark assuming we have no b****y brain or brains trust to discuss it with.
I have a list of parameters that I want answered and they will not or cannot answer me.

It can cost me more than the value of the TC to freight it to Australia - it's a lot of coin to part with on someone elses' opinion of what I need for my style of driving and what I want my Jeep to be capable of doing at the right time repeatedly and reliably. In my country I cannot just get it fixed and buy parts.

I want to know those parameters VWDiesel hints at and more but they don't or won't answer me.
Comments like "Oh we haven't gone to heavier springs yet but it is a HD TC - well I don't want THAT TC.
That affects my abilities to reduce friction and the metal particulates circulating in my tranny (regardless of filtration and in a closed system the supplied filtration should not need augmenting although I have considered that too) and keeping heat down increasing the life of the dang thing.

They also seem to be oblivious to the fact that from a marketing point of view they could impress the members of this forum (and other forums) worldwide and do a lot more business. I thought things were tough these days.....the customer should always come first.

Sorry for the rant but this is a very frustrating buying experience.

woodtick · **Posted:** Sun Nov 03, 2013 9:57 am

In my last CRD I had 3 stock replacements in 8 months. :evil:

Then I got the Euro TC. That worked flawlessly.

Then I wound up rolling it 4x. :roll:

Now CRD 2 is looking at the same thing.

More info is always helpful when trying to make an informed decision.

WWDiesel · **Posted:** Sun Nov 03, 2013 12:22 pm

Auberon, I fully understand your frustration! :banghead:

I think to some degree it may be a marketing strategy to keep the masses in the dark and hopefully make purchases on word of mouth and advertised recommendations rather than informed decisions based on real facts. I fully understand your dilemma, as a very dear friend shipped some items while in Australia back to the states and it cost him 700 dollars shipping, I was floored at the costs! :shock:

Do yourself a favor, get up in the middle of the night over there and call Suncoast (800) 868.0053 or (850) 864-2361 or email them (http://www.suncoastconverters.com/contact/) and see if they will answer all your questions and concerns. :?:

I like the Suncoast due to my experience with my Cummins and the fact that the guy who got me to try one is a diesel truck racer and he had personally tested everything out there and knew what worked and what did not, he broke a bunch of them. A TC for my Cummins was not cheap, $1800 to buy not including installation, a hard decision, one I now do not regret.

In my opinion, I cannot imagine a Chrysler mass produced TC for CRD's being in the same league with a Suncoast TC but if I had real numbers and specifications my mind could be changed. In your case with the extremely high shipping costs involved I doubt I would gamble when looking at a 300$ difference between TC's a total cost mistake including shipping twice... :2cents:

papaindigo · **Posted:** Sun Nov 03, 2013 1:00 pm

If you want to talk details with Suncoast I'd suggest going directly to the head person who is Ron Wolverton whose direct email last I knew is ron@suncoastconverters.com

Nice guy gave me a tour of the facilities when they did my TC install.

I say this because when I first called whomever answered the phone said they did not do TC installs. Several months later after installing my GDE Stage II turbo I really needed a TC upgrade (stock OEM TC won't handle that turbo unless you baby the go pedal) I spoke directly to Ron and he was happy to arrange an install at their location which is only a couple of hrs drive from my home.

Auberon · **Posted:** Sun Nov 03, 2013 11:28 pm

Thanks for the support gents. Person to person has a lot to be said for it. Papa, now I have a person to speak with that's wonderful.
Saving madly to cover that dang freight component for the present. As WWDiesel correctly said that is a big factor.
Thank you both. Cheers and much gratitude.

WWDiesel · **Posted:** Mon Nov 04, 2013 12:00 am

Ranger1 wrote:

Quote:

Got this pm from Ranger1
Check with MacD on LOST - he lives in Australia and had a SunCoast shipped by USPS for far less than UPS or Fedex. I didn't know our post office system shipped there but they do.

That was several years ago and it was much less than half of what UPS charged. He's had the SunCoast in his CRD for several years now and could be a good resource for this other gent to pm.

Regards,
Ranger1

Hope this helps on the shipping problem, worth checking into. :roll:

sailwa66 · **Joined:** Mon May 14, 2012 9:57 am **Posts:** 32

GreenDieselEngineering wrote:

The mopar euro TC is exactly the same as the stock one, except for stiffer lockup clutch springs.

The PO claimed that there was an updated TC in the Jeep when I got it, and I experienced no shuddering. Whether it was a 'Euro' unit or not, he couldn't tell me, nor can I tell from looking at it. What I do know is; after installing the Suncoast, the difference in apparent stall speed between the two is very small:

BS (Before Suncoast), I couldn't get 4th to lock unless I held at least 2100rpm on flat ground.

AS (After Suncoast), I can't get 4th to lock unless I hold at least 1950-2000rpm on flat ground.

And there is little discernible 'feel' between the two... They're both ridiculously 'loose', IMO. If I'm accelerating moderately through 40-45mph and give it 1/3 throttle, the engine jumps at least 600rpm, with virtually no increase in acceleration. Once it hits the magic 50mph, the TC locks, and THEN it takes off.

Just seems like a lot of wasted fuel because of these loosey goosey TCs.....

flash7210 · **Posted:** Wed Nov 06, 2013 8:30 pm

Torque converters just behave differently with diesel engines.
At work I drive a GMC 6500 with a inline CAT engine and 4 speed Allison automatic transmission.
That truck will barely move below 2000rpm and you have to get it above 2200 before it will shift.

A "tighter" torque converter in your CRD will just bog down the engine when stopped at a light and
you will nearly have to stand on the brake just to keep it stopped.
What you (and every CRD owner) really need is a 6 speed manual transmission.

CRD Joe · **Posted:** Thu Nov 07, 2013 12:37 am

I have a SC TC and the Transco shift kit. I STILL occasionally get shutter. That bothers me.

WWDiesel · **Posted:** Thu Nov 07, 2013 8:24 am

flash7210 wrote:

Torque converters just behave differently with diesel engines.
What you (and every CRD owner) really need is a 6 speed manual transmission.

Now that would really be sweet!! :-)r

I get to select shift points and no slippage :mrgreen:

Lower stall speed TC than Suncoast?

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