Disappointing Dyno #'s

[BigYellowIron]

Ok well i went to the little dyno meet in kansas city with the phords. I have the #6 tst 230/605 KN filter stright pipe on my 95 with an automatic. the trans is stock.
my dyno #'s were 160 hp at 1900 and 431 ftlbs torque. Are these numbers normal? I thought tst rated their plates at what you should expect at the rear wheels. The dyno was a dyno jet. Just wanted to know if this is normal. The plate was a huge power increase from stock, just thought my numbers would be better.
Adam


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"POWERSTROKE THIS"
Adam Harman
95 auto red and white #6 tst , eagle alluminum wheels. Stright pipe, Still BOMBING

 

[Strick-9]

Was your torque convertor locked during the run? If not, that would explain the loss of power.

Did you not have a hp peak recorded or just the torque peak?

Did you have a tach signal hooked to the truck during the run to get rpm and horsepower?

-Chris

 

[SlyBones]

Someone around here posted recently a formula for calculating hp from torque and visa versa.

431 at 1900 RPM = 155. 9 HP. Looks close enought to figure you only got peak torque and HP level at peak torque. This is probably not your peak HP.

Cool pic below.
431. 2 at 1950 RPM = 160. 09 HP using the formula.

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1997 2500 4x4, CC, Auto, 3. 54 LSD, 66K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Canopy, BedLiner, and tons more.

[This message has been edited by SlyBones (edited 03-26-2001). ]

 

[BigYellowIron]

Strick, I will have to e-mail you the dyno print out I cannot figure out how to get it on here. My converter was not locked up.
Adam

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"POWERSTROKE THIS"
Adam Harman
95 auto red and white #6 tst , eagle alluminum wheels. Stright pipe, Still BOMBING

 

[Strick-9]

Here is BigYellowIron's dyno printout.

#ad


Your torque convertor is eating up all the rest of the power. How much power a torque convertor puts to the ground is dependant on the difference in rpms between the engine and transmission. For a stock torque convertor you have to have a big (several hundred) difference in rpms to transfer substantial power.

During the test, I'm sure your engine reved up fairly quickly and the wheel speed slowly caught up. Let's say your engine was turning a constant 2500 rpms, as the input shaft speed approaches engine speed, less and less torque is transmitted through the torque convertor. This explains the steady loss of power when it should be increasing to a peak at 2500 rpms.

It makes for poor dyno numbers, but nothing to worry about in my opinion. Your engine is probably making the 230/605, but you just won't see it until lockup. That is the reason why some of us spend so much money on better torque convertors. #ad


-Chris

 

[Timinator]

How was a '95 able to rev so high without modification? I thought the governor would decrease fueling long before then. Is that a by-product of the TST plate?

 

[SlyBones]

I too am interested in the variability of RPM limits. For example if I just floor it from a stop, I can get 2750 in first, only 2600 in second, then 2750 in third. The second to third shift happens quick and does not get 2750 like other gears. Is this limited by transmission shift points, and not fuel govener cutoff?

However I can to out on I-5, do about 50 and push the OD lockout button. transmission goes into third gear, lockup. Now floor it. Runs to 3000 RPM. Is this the real gov cutoff?


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1997 2500 4x4, CC, Auto, 3. 54 LSD, 66K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Canopy, BedLiner, and tons more.

 

[Strick-9]

BigYellow,

I edited the picture you emailed to me. I rotated it and shrank it down with corel photo paint. I then uploaded it to my website and posted a link to that file.

Slybones:
The governors on the early year trucks were indeed set lower. Fueling is being cut back at 2200 rpms, but the truck still has a high idle speed of near 3000 rpms. You have no power at that engine speed, but the engine will rev that high under low load (i. e. lower gears) That is why you can reach 3000 rpms when you downshift at 50. There isn't much load on the engine.

-Chris

 

[John_P]

Big Yellow:

Those dyno figures look low to me. Before
I had my 370 injectors and "pump mods"
done last year I was similarily equipped
to your truck. I have a 96' automatic
and had the #6 TST plate also.

At that time my truck dynoed at 225 H. P. /
625 Torque on a "Mustang" Dyno at "Scheid
Diesel", Effingham, Illinois. When I did
that "run" I had just installed a new TC
and valve body, so maybe that made a
difference.

--------
John_P

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Red '96 4x4 2500 Auto 3. 54, TST #5, Major Pump Mods(By "Scheid Diesel") 370 Diamond B Injectors, Gov. Spring kit, AFC Spring kit, Banks Exhaust, Prime Loc, Cummins Chrome Kit,Psychotty Air Filter, Pro-Torque Converter, BD Valve Body, BD Pressure Loc, Isspro Gauges, Sendel 16" Alum Wheels w/ 33" BFGs

 

[BigYellowIron]

strick
How did you get my dyno numbers on the tdr, I think it is with photo point?
Adam

 

[Steve St.Laurent]

That's the strangest dyno chart I've ever seen! Your hp peak should be WAY higher (in RPM) than your torque peak, plus there's a spike on both runs at between 2750 - 2850. VERY strange.

-Steve

 

[vc]

for us that are still learning about this, when you guys are talking about the tc locked up versus not, how do you lock it or unlock it. Which way will give me fastest 0-60 speed if I want to smoke a friend off the line?
Thanks

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'97 Ram,auto,3. 54 lim-slip,4x4,smoothie,BD(TST)#8 fuel plate-slid forward,Prime-Loc,VDO Vision pyro/boost,HiddenHitch class V Magnum.

 

[Strick-9]

vc,

You COULD lock up your torque convertor to beat someone in a race. I used to do it all the time. I'm on my third transmission in less than a year and I learned the hard way not to use the TC clutch lining for acceleration.

Buy a good torque convertor. Even if it costs $1000 it will save you money in the long run over using a mystery switch.

To answer your question. Search the archive for installing mystery switch. You could also visit TST's website. They have instructions for lockup switches I believe.

Don't say I didn't warn you though.

-Chris

 

[SlyBones]

OK, I'll bite... .

If we dont what the TC locked up, because we dont want to buy 3 trannys in one year, and not having it locked up provides these poor dyno runs, then how are we supposed to smoke powerjokes? .....

Was the transmission supposed to go from unlocked to locked some where in the course of the acceleration ( dyno ) run? Or is the TC lockup only used in OD or 3rd, with the OD locked out? ( Not including exhaust brakes )

I asked before and thought I got it, but now I seem confused again... .

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1997 2500 4x4, CC, Auto, 3. 54 LSD, 66K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Canopy, BedLiner, and tons more.

 

[BCFAST]

with an automatic, the more power the motor makes, the faster the gearbox burns up... very little of the added power actually gets to the ground. The automatic transmission is a terribly inefficient mechanism that eats power... I suggest a call to Bill K.

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97 2500 CC 4x4 3. 54 5spd, Green, #12 plate slid all the way forward, 4inch open exhaust, 235/85 Michelins, RS 9000's, PrimeLoc, Red Tops, TDR cloisonae grill badge!

 

[Strick-9]

Slybones,

The transmission should not go from unlocked to locked during a full power run. That would be very hard on the clutch lining.

Lockup torque convertors were desingned for better fuel economy to be used during cruise conditions.

If you want more power transferred to the ground, then rev her up a little more. More rpms = more power transferred. I've never been beaten by a powerstroke with either my stock TC or DTT's.

If someone wanted to produce a better dyno run, they could turn OD off and use a mystery switch to lock the transmission in 3rd gear. Mash the throttle at 1500rpms and hope for the best.

That would make for a nicer piece of paper to talk about, but wouldn't change how the truck drives on the road. It would be nice to see both runs from the same truck so we could all see the TC inefficiencies.

-Chris

 

[SlyBones]

Ya know sometimes ya just gotta beat this stuff into me with a stick. So... .

I have seen lots of Dodge advertised charts and a few other dyno reports in the past. I too expected to see peak HP way higher in the RPM's. However this is not the case, here.

OK so dodge is displaying crank measurements. Can I assume this is the true curve for the engine itself?

Next if we dyno'd a manual transmission with a clutch locking up the entire way, we would see the typical HP/Torque curves?

So this just happens to be how automatics deliver power to the ground? The better the TC, the better the curve. We could achieve the typical curve by locking up the TC, at the cost of destroying the lockup clutch and rebuilding the transmission too often.

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1997 2500 4x4, CC, Auto, 3. 54 LSD, 66K, Everything inc Leather, K&N, 4" BD cat-back, otherwise stock, Isspro Gauges(3), 285/75/16 on Alcola's, RS9000's, Canopy, BedLiner, and tons more.

 

[Strick-9]

Sly,

You got it! A locked TC or a manual transmission would display the graphs you are used to seeing.

-Chris