: Torque Multiplier Upgrade ??????? hmmm



AJxtcman
03-23-08, 11:06 AM
I need some input guys

I think I need to change my Torque Multiplier!

What do I need to know to get the best one for my 2700 lbs car?

If this works for me how do I find the best one for a 4000 lbs car?

I don't know everything and need some help!

I can data log the car if that will help, but then what?

Does anyone know of an equation?

I plan on that blower for my car, but what about the 4000 lbs Caddy owner?

dkozloski
03-23-08, 11:43 AM
A torque multiplier/amplifier is a piece of pipe slid over the handle of your Stillson pipe wrench. A torque convertor is the connection between your engine and the transmission. What are we talking about?

AJxtcman
03-23-08, 12:01 PM
A torque multiplier/amplifier is a piece of pipe slid over the handle of your Stillson pipe wrench. A torque convertor is the connection between your engine and the transmission. What are we talking about?

The stator? I am not sure

Turbine can't be the one. I think it is the stator. I need some engineering help!

A formula for this maybe.

Maybe a smaller turbine? :hmm:

Someone here has to know.

dkozloski
03-23-08, 02:19 PM
It gets complicated quick because your have to cut the welds on a lathe to get the convertor apart. Then you remove some of the vanes on the drive and driven side, weld it back together and see what you get. Back in the day, Buicks actually had a system that changed the angle of the vanes on the stator hydraulically. This technology was picked up by the aircraft turbine manufacturers and was a major breakthrough in turbine engine design. Because this is a complicated deal even for a well equipped machine shop most guys go with aftermarket stuff. In most cases, unless you intend to use the car only on the strip, it quickly becomes one of those deals you wish you had left alone. A car with a loose torque convertor, drives on the street like real peanut butter drive and quickly becomes annoying.

codewize
03-23-08, 07:12 PM
The only input I have is from Edge racing. This is when I was asking a lot of questions about torque converters. They told me they'd set the STR (Stall Torque Ratio) to 2.4. That was the best suggestion for my specific application.

What that means is up to the Stall speed, the torque is multiplied by 2.4

Does that help ?

AJxtcman
03-23-08, 07:33 PM
The only input I have is from Edge racing. This is when I was asking a lot of questions about torque converters. They told me they'd set the STR (Stall Torque Ratio) to 2.4. That was the best suggestion for my specific application.

What that means is up to the Stall speed, the torque is multiplied by 2.4

Does that help ?

I can order parts for a converter.
I can have them built.
I would rather have them built.:thumbsup:

Does this mean I would get 275 ft lbs X 2.4 @ 2000 RPM's?
660ft lbs is pretty good. What about DTC's?

Now looking at this you don't need your stall to lock until 3250RPM's.
So you would multiply torque up to 3250?
If I bought a 3500 and the stall speed end up at 2600 RPM's I would be missing some power correct? I may be upset.
I would not like to have to pull the trany back out because they messed up.
How do you design a converter?
http://i224.photobucket.com/albums/dd25/AJxtcman/PCM%20Stuff/Y-21.jpg

AJxtcman
03-23-08, 07:37 PM
:shhh: How would that work on the street?

dkozloski
03-23-08, 07:45 PM
Read a little bit here. This is not a good condidate for amateur hour.

http://en.wikipedia.org/wiki/Torque_converter

dkozloski
03-23-08, 07:48 PM
:shhh: How would that work on the street?
A high stall torque converter generates a hell of a lot of heat. I've seen units that get the oil so hot that it all blows out the dipstick hole.

AJxtcman
03-23-08, 08:43 PM
TCI Torque Converters Explained

Torque converter --- a torque converter is a fluid-coupling device that also acts as a torque multiplier during initial acceleration.

The torque converter consists of four primary components:

Cover --- the cover (also referred to as a front) is the outside half of the housing toward the engine side from the weld line. The cover serves to attach the converter to the flywheel (engine) and contain the fluid. While the cover is not actively involved in the characteristics of the performance, it is important that the cover remain rigid under stress (torsional and thrust stress and the tremendous hydraulic pressure generated by the torque converter internally.)

http://www.tciauto.com/Products/TechInfo/converter_exploded_view.jpg
Turbine --- the turbine rides within the cover and is attached to the drive train via a spline fit to the input shaft of the transmission. When the turbine moves, the car moves.

Stator --- the stator can be described as the "brain" of the torque converter, although the stator is by no means the sole determiner of converter function and characteristics. The stator, which changes fluid flow between the turbine and pump, is what makes a torque converter a torque converter (multiplier) and not strictly a fluid coupler.

With the stator removed, however, it will retain none of its torque multiplying effect. In order for the stator to function properly the sprag must work as designed: (1) It must hold the stator perfectly still (locked in place) while the converter is still in stall mode (slow relative turbine speed to the impeller pump speed) and (2) allow the stator to spin with the rest of the converter after the turbine speed approaches the pump speed. This allows for more efficient and less restrictive fluid flow.

The sprag is a one-way mechanical clutch mounted on races and fits inside the stator while the inner race splines onto the stator support of the transmission. The torque multiplier effect means that a vehicle equipped with an automatic transmission and torque converter will output more torque to the drive wheels than the engine is actually producing. This occurs while the converter is in its "stall mode" (when the turbine is spinning considerably slower than the pump) and during vehicle acceleration. Torque multiplication rapidly decreases until it reaches a ratio of 1:1 (no torque increase over crankshaft torque.) A typical torque converter will have a torque multiplication ratio in the area of 2.5:1. The main point to remember is that all properly functioning torque converters do indeed multiply torque during initial acceleration. The more drastic the change in fluid path caused by the stator from its "natural" return path, the higher the torque multiplication ratio a given converter will have. Torque multiplication does not occur with a manual transmission clutch and pressure plate; hence the need for heavy flywheels, very high numerical gear ratios, and high launch rpm. A more detailed discussion of torque multiplication can get very confusing to the layman as high multiplication ratios can be easily considered the best choice when in fact more variables must be included in the decision. Remember, the ratio is still a factor of the engine torque in the relevant range of the torque converter stall speed, i.e.: a converter with a multiplication ratio of 2.5:1 that stalls 3000 rpm will produce 500 ft.-lbs. of torque at the instance of full throttle acceleration if its coupled to an engine producing 200 ft.-lbs. of torque at 3000 rpm. However, if this same engine produces 300 ft.-lbs. of torque at 4000 rpm, we would be better off with a converter that stalled 4000 rpm with only a 2.0:1 torque multiplication ratio, i.e.: 300 x 2.0 = 600 ft.-lbs. at initial acceleration. Of course it would be better yet to have a 2.5:1 ratio with the 4000 rpm in this example (provided his combination still allows the suspension to work and the tires don't spin.) This is just a brief overview as the actual scenarios are endless.

Impeller pump --- the impeller pump is the outside half of the converter on the transmission side of the weld line. Inside the impeller pump is a series of longitudinal fins, which, drive the fluid around its outside diameter into the turbine, since this component is welded to the cover, which is bolted to the flywheel. The size of the torque converter (and pump) and the number and shape of the fins all affect the characteristics of the converter. If long torque converter life is an objective, it is extremely important that the fins of the impeller pump are adequately reinforced against fatigue and the outside housing does not distort under stress.

Stall speed --- the rpm that a given torque converter (impeller) has to spin in order for it to overcome a given amount of load and begin moving the turbine. When referring to "how much stall will I get from this torque converter", it means how fast (rpm) must the torque converter spin to generate enough fluid force on the turbine to overcome the resting inertia of the vehicle at wide open throttle. Load originates from two places (1) From the torque imparted on the torque converter by the engine via the crankshaft. (This load varies over rpm, i.e. torque curve, and is directly affected by atmosphere, fuel and engine conditions.) (2) From inertia, the resistance of the vehicle to acceleration, which places a load on the torque converter through the drive train. This can be thought of as how difficult the drive train is to rotate with the vehicle at rest, and is affected by car weight, amount of gear reduction and tire size, ability of tire to stay adhered to ground and stiffness of chassis. (Does the car move as one entity or does it flex so much that not all the weight is transferred during initial motion?)

Note: While referring to the resistance of the vehicle to move while at rest, the torque converter's stall speed and much of its characteristics for a given application are also affected by the vehicle's resistance to accelerate relative to its rate of acceleration. This resistance has much to do with the rpm observed immediately after the vehicle starts moving, the amount of rpm drop observed during a gear change and the amount of slippage in the torque converter (turbine rpm relative to impeller pump rpm.) A discussion involving how resistance to acceleration affects a torque converter involves more theory than fact and must involve all the dozens of other variables that affect rpm and slippage. The primary thing we want to remember about torque converter stall speed is that a particular torque converter does not have a "preset from the factory" stall speed but rather its unique design will produce a certain range of stall speeds depending on the amount of load the torque converter is exposed to. This load comes from both the torque produced by the engine and the resistance of the vehicle to move from rest. The higher this combined load the higher stall we will observe from a particular torque converter, and conversely, the lower the load, the lower the stall speed. Naturally, if the engine is not at wide open throttle we will not expect to observe as high a stall speed as we would under a wide open throttle.

Another point concerning engine torque is that we are only concerned with what we'll call the "relevant range" of the engine torque curve when discussing initial stall speed. This means if our particular torque converter chosen has a design that should produce a stall speed in a range of say 2000 to 2600 rpm given the application then we would refer to this as the relevant range of our interest in the engine's torque curve for this particular torque converter. In other words, only the torque characteristics of the engine torque in this rpm range will affect the amount of stall speed we actually observe. If we are using a high horsepower/high rpm engine that does not make much torque before 3000 rpm, it does not matter that the engine makes excellent torque over 3000 rpm if we are trying to use the torque converter in this example because its relevant range is 2000-2600 rpm and we would expect to see poor stall (2000 rpm or less) due to the poor torque produced by the engine in this range.

Choosing the correct application torque converter - The buyer of a performance torque converter normally has very specific "wants" to be filled, namely: They want to improve the performance of their vehicle. This can mean they may want the new torque converter to help the car run quicker, run faster, idle in gear better, leave from a stop harder, "chirp" the tires on the gear changes, or pull a steeper hill. The buyer may be looking for any or all of these performance improvements.

They want to improve the dependability of their vehicle meaning they want to get rid of existing drive train failures they are currently having with either OEM or competitors products such as short life (to what they perceive is a proper life), "trash" related transmission failures, overheating, hard part breakage, engine problems that they may believe is caused by torque converter and general unreliable performance.

They may have been told by friends, salespeople, advertising, technical articles, etc. that their particular application needs to have a "stall" converter. This is particularly true of first time performance camshaft purchasers where the salesperson or the camshaft catalog will recommend a higher than stock stall speed torque converter.

A torque converter does not function in a void by itself. The torque converter is an integral part of the total vehicle combination. While many vehicle combinations and applications are very similar and it may seem obvious what the best torque converter selection is, it is normally a wise step to take a look at the intended application and choose the best torque converter for the particular application. TCI® uses an application questionnaire to gather the pertinent information. TCI® technical salespeople also spend a large portion of their day reviewing specific customer applications and recommending torque converters for those applications. There is no "black magic" formula that the variables can be plugged into resulting in a definitive torque converter choice. Torque converter choices are made based on accumulated historical knowledge of performance in various applications and the use of all or several basic charts and ratios derived through this historical information. As with many other automotive performance parts, torque converter design and construction is a dynamic art and can not be patterned on the results of a "plug-in" formula or solely allowed to follow the historical applications. TCI® looks at torque converter technology as an on going process of continuous improvement.

We are in a more fortunate position when dealing with street and mild off-road applications because there are greater numbers of similar vehicles as compared to racing-oriented applications. This allows TCI® to perform most of the particular design features on categories of torque converters (i.e.: Saturday Night Special®, Breakaway® and StreetFighter® styles) rather than have to set a unique combination for one particular torque converter as we have to do quite often with the more uncommon race applications. This also permits TCI® to provide training in the form of seminars, videotapes and technical literature to the sales staffs of our leading warehouse distributors and jobbers enabling the phone salesperson or counter-person to recommend a street or street/strip application in the majority of cases.

Dependability concerns in choosing a torque converter - Regardless of the reason or "want" for buying an aftermarket torque converter, an educated buyer should look for several features in the product he is considering purchasing in order to assure that he can reasonably expect to receive dependable results and long life from the purchase.

Furnace brazed fins - greatly improves the strength characteristics of the fins. The furnace brazing causes the housing and fins to move and act integrally as one unit. This greatly reduces the amount of flex, which causes fins to bend and break. Also, the more rigid the fins stay while under pressure, the more consistent the behavior of the torque converter.

Needle bearings - properly selected and installed bearings withstand more pressure and provide less internal drag (drag robs horsepower and increases heat) than can be achieved with OEM style thrust washers. Thrust washers also tend to flake off material adding to contamination in the system (the transmission/torque converter hydraulic system.)

Service and time proven manufacturer - Ask for recommendations from leading car enthusiasts in your local area or check out what the racers are using.

Drivability concerns in choosing a torque converter - A performance torque converter should not compromise one aspect of car performance to achieve another. When investigating a converter purchase ask whether the particular torque converter being looked at may improve initial takeoff at the sacrifice of top end mph or other similar results, questions, etc. With the technology and product available today a buyer very seldom needs to sacrifice one area of performance to gain in another. However, without proper selection assistance or guidance (and with many under engineered products on the market today) it is unfortunate that many buyers end up with a product that does not best suit his needs or expectations. Too low a stall torque converter will not benefit the customer. If the user has an application which requires at least 3000 rpm stall and they purchase a 2000 to 2500 rpm stall range converter, it will normally not even give them the 2000 rpm stall. It will act very similar to the stock torque converter they just removed.why? Because the engine needs to operate in its optimum rpm range and since the chosen torque converter is below that range, it is not getting enough load from the crankshaft side to operate as designed. Symptoms include engine stalling when in gear at a stop, low stall speed, hesitation when going to full throttle, a "bog" when leaving from stop at wide open throttle. Too high a stall range torque converter will not benefit the customer. You will see this situation most often when the customer does not have sufficient gear ratio for the converter stall range or the engine is not capable of the appropriate rpm range (too small a duration camshaft, inadequate valve springs, too low compression, etc.) Symptoms include high "revs" to pull away from stop, "marshmallow" accelerator feel when driving at part throttle, transmission and possibly engine overheating, and a pronounced engine rev when nailing the throttle from a cruising speed.

CadillacSTS42005
03-23-08, 09:18 PM
all this is greek to even me....
but so long as it makes 4200 lbs shoot 0-60 in faster times
im game

codewize
03-23-08, 11:21 PM
AJ, what you described there in your post is correct. I spent a lot of time with Andre from Edge racing explaining what we had done, what I wanted from the car. There were many discussions about heat, driveability and such.

The outcome was he told me that the TC would probably run cooler than stock, he recommended 3000 RPM stall, 3200 at the highest. There are no driveability issues and the folks here who have changed TC's have sworn up and down that there are no DTC issues.

The STR is altered by changing the angle of the fins on the stator. Edge does NOT just go in and bend fins like some companies do. They use new parts with the specs they're after to assemble the TC you desire.

The idea is that the torque is increased below stall to help a.) Launch the car and b.) Bring up the RPM's faster to get into the power band. Thus decreasing 1/4 mile ET's and putting more power to the pavement.

dkozloski
03-24-08, 01:48 AM
I always preferred the old four speed Hydramatic with a fluid coupling rather than a torque converter. It was all heavy as hell because it was all steel but at the time I was using them you didn't need a scatter shield because nothing ever got out of the case. Fairbanks Automotive and B&M built the best ones I ever saw. My buddy and I had a '58 Bel Aire with a 283 bored and stroked to 358 cu in. We used a Latham axial flow blower with four Carter side drafts and a Chet Herbert cam. That thing got rubber with every shift and ran in the low elevens.

AJxtcman
03-24-08, 07:12 AM
AJ, what you described there in your post is correct. I spent a lot of time with Andre from Edge racing explaining what we had done, what I wanted from the car. There were many discussions about heat, driveability and such.

The outcome was he told me that the TC would probably run cooler than stock, he recommended 3000 RPM stall, 3200 at the highest. There are no driveability issues and the folks here who have changed TC's have sworn up and down that there are no DTC issues.

The STR is altered by changing the angle of the fins on the stator. Edge does NOT just go in and bend fins like some companies do. They use new parts with the specs they're after to assemble the TC you desire.

The idea is that the torque is increased below stall to help a.) Launch the car and b.) Bring up the RPM's faster to get into the power band. Thus decreasing 1/4 mile ET's and putting more power to the pavement.

So you order up a 3500 stall and get a 2600.
You think it though and add a solid front mount.
Now you get a car that steers all over the road on launch.
Then you add a set of 18" tires and make the 245's
You still are not getting everything out of the car and it pulls all over the road.
You add a button to increase torque output and stop the T/C from kicking in.


If you remember I said that the the power was turned up in one of the PCM's, but the amount of power defeat from the Torque Management system was more. Basically if you don't spin the tires you could get more power out of that PCM, but the millisecond that the tires spin the Torque Management system takes more out than other programs have. You have to see all the tables in the software.

Now back onto this $500 torque multipler problem. I need to know what I am getting. If I spend $500 for a part it better be the correct one. In the old days hacks cut out or bent over the vanes. I want a properly designed Torque Converter and it starts with the Torque multiplier!:rant2:
$500 and it is off by 900 RPM's:rant2:

codewize
03-24-08, 09:33 AM
Hmm no AJ I don't think you order 3500 and get 2600. I must have missed that part.

I'm pretty sure if you order a TC from one of the reputable places like Edge or Yank you're going to get what you ask for using real parts not bent up parts. I bugged them about that for a while.

Yes I've always considered a solid motor mount.
I love torque steer LOL
And of course I understand the concept of spinning tires loosing power

Give me a little more insight as to what you're stirring up and I'll try to be more helpful. Or is the TC the $500 part you speak of.

AJxtcman
03-24-08, 01:31 PM
Hmm no AJ I don't think you order 3500 and get 2600.



Give me a little more insight as to what you're stirring up and I'll try to be more helpful. Or is the TC the $500 part you speak of.

I talk to one of my new good friends Dennis. He explained that you get about 80% lock at the 2600. That would explain it. I though on one trip I was at 3000, pulling a hill at 65 mph after I disengaged the lock up.

AJxtcman
03-29-08, 08:12 PM
This is what I came out with. Traction control off on both runs

.
Start of both runs
Old
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Oldconvertertractionoffstart.jpg

New
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Newconvertertractionoffstart.jpg

.
0 mph vs RPM's
Old 645 RPM's
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Oldconvertertractionoff0mph.jpg

New 2513 RPM's
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Newconvertertractionoff0mph.jpg

.
Initial stall speed vs RPM vs MPH
Old 1967 RPM's
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Oldconvertertractionoff1967.jpg

New 2513 RPM's
Oh wait :eek: it has not moved:cool:
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Newconvertertractionoff0mph.jpg

.
I am thinking full stall speed
Old 2622 RPM's ?
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Oldconvertertractionoff2622.jpg

New 3298 RPM's ?
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Newconvertertractionoff3298rpm.jpg

.
0 MPH to 6400 RPM's vs time
Old 4.742 seconds
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/oldconvertertractionoff6400.jpg

New 4.378 seconds
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Newconvertertractionoff6400rpmshift.jpg

:bouncy:
RPM drop on shift
Old 2315
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Oldconvertertractionoff2315rpmdropo.jpg

New 2353 not too loose. The 38 more drop maybe from the tires?
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/Newconvertertractionoff2153rpmdropo.jpg

AJxtcman
03-29-08, 08:33 PM
Take a look at this. Hmmm One looks stronger
http://i224.photobucket.com/albums/dd25/AJxtcman/Bert/converter/test.jpg

turbojimmy
09-15-08, 02:50 PM
Hmm no AJ I don't think you order 3500 and get 2600. I must have missed that part.

I'm pretty sure if you order a TC from one of the reputable places like Edge or Yank you're going to get what you ask for using real parts not bent up parts. I bugged them about that for a while.

Yes I've always considered a solid motor mount.
I love torque steer LOL
And of course I understand the concept of spinning tires loosing power

Give me a little more insight as to what you're stirring up and I'll try to be more helpful. Or is the TC the $500 part you speak of.

Bump for an old post:

Codewize: did you ever put a higher stall converter in your car? I need to take my trans out to replace the TC solenoid and I'm thinking about putting a high-stall converter in. The DTS 'launch' is lazy because you have to wait until it gets into the 'power band' of the revised cams.

I talked to Yank and they said they've done them before. They said they did a 3600 RPM stall for one Cadillac customer, which seems like too much for daily driving.

Thanks,
Jim

AJxtcman
09-15-08, 04:21 PM
Bump for an old post:

Codewize: did you ever put a higher stall converter in your car? I need to take my trans out to replace the TC solenoid and I'm thinking about putting a high-stall converter in. The DTS 'launch' is lazy because you have to wait until it gets into the 'power band' of the revised cams.

I talked to Yank and they said they've done them before. They said they did a 3600 RPM stall for one Cadillac customer, which seems like too much for daily driving.

Thanks,
Jim

PM sent

MisterBlue
09-17-08, 08:31 PM
I doubt the N* slushbox would take the gaff of a racing convertor. It does little good to change the convertor, and then have to constantly replace gearsets and clutchpacks.

turbojimmy
09-17-08, 08:39 PM
I doubt the N* slushbox would take the gaff of a racing convertor. It does little good to change the convertor, and then have to constantly replace gearsets and clutchpacks.

After looking at the relatively flat torque curve it doesn't look like moving the launch RPM up any higher will do much good anyway.

Jim

AJxtcman
09-17-08, 09:06 PM
I doubt the N* slushbox would take the gaff of a racing convertor. It does little good to change the convertor, and then have to constantly replace gearsets and clutchpacks.

This is NOT a 4T65E!

This is a 4 T 80 E!
4 = 4spd

T = Transverse

80 = The level of Torque

E = Electric

The 1 ton trucks with the huge trany's ran 80's (4L80E) forever!

Have you ever heard of a Chain or gear set failure?

I have NEVER seen one.

I have seen some clutch and band failure, but they are caused by worn bushings or warped channel plates. This causes a fluid leak and the lack of pressure allows the clutches to slip or the leak may pressurize another clutch or band and cause it to drag!

Now on to the converter. I had a GM engineer look at some data logs and he said 3000 minimum and he really felt like a 3500 would be the best. Also the TCC will still start locking up at 35 mph, so you won't have anymore stall speed than the factory would at this point!

Just think about it.

AJxtcman
09-17-08, 09:18 PM
This trany is very heavy duty



Caution: The forward and coast clutch assembly weighs approximately 50 lbs. Personal injury may result if you drop the assembly.

Install the J 39053 . Using a chain hoist or suitable lifting equipment, secure and lift the forward and coast clutch assembly (626-834) out of the case.

http://i224.photobucket.com/albums/dd25/AJxtcman/Trans%20Parts/11871.gif

AJxtcman
09-17-08, 09:21 PM
http://i224.photobucket.com/albums/dd25/AJxtcman/dyno/TorqueCurve-00.jpg

Like I said a GM engineer said 3500

AJxtcman
09-17-08, 09:25 PM
After looking at the relatively flat torque curve it doesn't look like moving the launch RPM up any higher will do much good anyway.

Jim

How any NON VVT do you know of that have a 4000 rpm range?
That would be 2500 to 6500 correct?
How about 3500 to 6500? This would = a 3000 rpm rang. Does that sound familiar? Take a look at some cam specs for a SBC and the RPM range.

AJxtcman
09-17-08, 09:27 PM
This is a 3500 stall
ztnK5e9BSF4

turbojimmy
09-18-08, 06:04 AM
How any NON VVT do you know of that have a 4000 rpm range?
That would be 2500 to 6500 correct?
How about 3500 to 6500? This would = a 3000 rpm rang. Does that sound familiar? Take a look at some cam specs for a SBC and the RPM range.

My intentions were to try to 'make up' for the lost torque over the LD8. Looking at the torque curve, that doesn't happen until ~4,500 where the lines cross over. Adding a few hundred more RPM to the stall isn't going to give me much more torque as I had hoped it would. 3500 RPM is way too much stall for a daily driver, IMO. I have a 3500 stall converter in my Grand National and it's great at the dragstrip but I wouldn't want to drive it around every day. MPG is in the single digits (okay, so there are other reasons for that) and the loose converter generates a lot more heat (I have an external cooler in addition to the stock cooler, which could easily be done on the Caddy, too). Listening to that DHS launch, while it sounds nice, reinforces why I wouldn't want to do that to my daily driver.

I thought maybe a few hundred RPM, maybe even like 600-800 over stock, would wake it up but I'm not so sure. 3,000 would be my max.

Jim

AJxtcman
09-18-08, 07:47 AM
My intentions were to try to 'make up' for the lost torque over the LD8. Looking at the torque curve, that doesn't happen until ~4,500 where the lines cross over. Adding a few hundred more RPM to the stall isn't going to give me much more torque as I had hoped it would. 3500 RPM is way too much stall for a daily driver, IMO. I have a 3500 stall converter in my Grand National and it's great at the dragstrip but I wouldn't want to drive it around every day. MPG is in the single digits (okay, so there are other reasons for that) and the loose converter generates a lot more heat (I have an external cooler in addition to the stock cooler, which could easily be done on the Caddy, too). Listening to that DHS launch, while it sounds nice, reinforces why I wouldn't want to do that to my daily driver.

I thought maybe a few hundred RPM, maybe even like 600-800 over stock, would wake it up but I'm not so sure. 3,000 would be my max.

Jim

Lets see if I get this correct or mess it all up.

I think the stock converter initially flashes to 1600 and then drops to about 1200 before the PCM starts to reduce power (shutting down injectors).

Try this I maybe wrong on my numbers.
Please report back to me on this.


How to perform a stall test (http://www.tpub.com/content/trucktractor6x4/TM-9-2320-363-34-1/css/TM-9-2320-363-34-1_23.htm)

How to perform a stall test #2 (http://www.txchange.com/stalltc2.htm)


Perform a second gear pull from a stop and see what RPM the engine wakes up at and what RPM it drops off at.
Please let us know again on this.


Next the Heat Myth.
Yes a higher stall usually generates more heat, but we need to look at the big/whole picture on this.
In the two link they tell you not to perform the test longer than 30 second Correct?
If you are loading the stall at 1200 RPM's it is generating more hea than if the stall was 2000 RPM's correct? I maybe wrong on that.
We found at the track the Trans Temps were way up and we had to let the trans cool off more that the engine.:eek: I am thinking 230° after a run without leaving on the brake. That means it occurs after a 1/4 mile WOT run. The runs reflected this also. They were all over the board. 3 or 4 tens apart even after some cool down time. We were trying for 180° or less on a run.

After the converter the runs are more consistent and the trans temp doesn't shoot up at all. We don't even monitor it at the track anymore. We can now make run after run and the times are with in a tenth.


Now the fuel economy. I have no clue it is not my car.
I can tell you that when the PCM starts enabling the TCC/VCC in as low as 2nd gear the stall is eliminated. If this was not the case the PCM would throw a DTC P0741.
The PCM starts TCC/VCC in second gear under non or low load condition. The converter is going into lockup in 2nd.:eek:

What speed do you come out of 2nd?
By that speed the TCC/VCC would over ride the Stall correct?

Like I said I probably messed this all up.

turbojimmy
09-18-08, 06:16 PM
I think the TC locks up above 40, not sure about 2nd gear. The GN locks up in 2nd but I don't think the Caddy does. It won't lock up unless you're at light throttle and off the brake anyway.

The heat thing is not a myth. A higher stall torque converter is slipping more than a lower stall converter. More slip = more heat. If the fluid coupling doesn't happen until 3500 RPM vs. 1600 stock, that's a lot of slipping. That's also why you're seeing the temps go up on the 1/4-mile run. But that's not to say an external cooler can't cool it down. Like I said, my GN has a 3500 stall converter in it with an external cooler and it's been fine. But then I only get about a season (2,000 miles) before I break the 2004R anyway :p

Looking at the L37 torque curve, I can see why 3500 is recommended. You'd get to the peak torque pretty quick. The curve isn't real steep, but moving up in RPM does give you more torque. I'll have to think about it some more. It just feels laggy off the line compared to my mom's LD8 car.

Jim

codewize
09-18-08, 07:27 PM
I think if you took an LD8 and mated it to a 4T80E with 3.71 gears with a 3000 RPM converter you'd easily put that 4000# car into the 14's.

But that's just my theory of course.

turbojimmy
09-18-08, 07:49 PM
I think if you took an LD8 and mated it to a 4T80E with 3.71 gears with a 3000 RPM converter you'd easily put that 4000# car into the 14's.

But that's just my theory of course.

Maybe. I'd like my DTS to squeak into the 14s. But I'm not sure how much I'm willing to pay to do it :)

Jim

AJxtcman
09-18-08, 07:53 PM
maybe. I'd like my dts to squeak into the 14s. But i'm not sure how much i'm willing to pay to do it :)

jim

$600?

codewize
09-18-08, 07:58 PM
Right exactly. That's all I'm asking for is to be in the 14's consistently.

From what I understand a hi-stall TC is good for about .5 sec. so right there is you're 14.9 ET

AJxtcman
09-18-08, 08:01 PM
Right exactly. That's all I'm asking for is to be in the 14's consistently.

From what I understand a hi-stall TC is good for about .5 sec. so right there is you're 14.9 ET

14.6 to 14.7 all day long on the motor.

turbojimmy
09-18-08, 08:05 PM
$600?

$600 and no DTCs? Need to get through NJ inspection.

Jim

AJxtcman
09-18-08, 08:38 PM
$600 and no DTCs? Need to get through NJ inspection.

Jim

NO DTC's. I have proof.

turbojimmy
09-18-08, 08:54 PM
NO DTC's. I have proof.

I'll give you a call tomorrow!