Dynamometer Questions

Da1Chief said:
Ok, trying to think this one out....

Obviously, I would want the truck tied down securly, but too much down pressure from the tie strap would be bad. That suggests that the direction of the tie straps should be more to the rear and front t cut down on the angle.

However, at a lower angle the tires would spin, which would be bad. This suggests that the tire pressure should be lower as to add better traction to the rollers.

The "Trick" would be figuring out what the ballance between the two are.

Is my thinking correct on this????
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From the what has been said already Changing gears druing the Pull would give wrong/bad readings on Torque numbers.

I could very easy press the "Tow" button on the Shifter and let the truck change gears up to normal. How do I keep it from kicking into Over Drive when I floor it for the WOT Pull??

As I have a Quad Cab (Automatic Transmission) Does mean that I would also want them to prevent the truck from changing gears/kicking into Overdrive druing the Pull????

If my thinking is correct How would I accomplish this?
 
You definitely want to push the tow/haul button. The button will lock out 4th gear. It has no other effect. So, it will shift 1-2, then 2-3, and then hold. But, the only way to keep it from doing a 3-2 down shift is to modify the govenor table curve in the computer or loosten up the TV cable just until the point to where it won't downshift at wide open throtle. The danger of doing this though is that your tranny could start slipping because of the lower associated line pressure with the looser cable. I wouldn't try this on a stock tranny. If you have a built tranny, it will likely be no problem.

The best way would be to modify the govenor curve in the ECU table and command 3rd gear to lock under wide open throttle. That way you could be in 3rd gear with the torque converter locked at around 20 mph and just stomp it from there and do a 20-120 mph pull, all in 3rd gear. It would give you a 1500 rpm - 6000 rpm pull. You will need software to do this though....
 
WOT said:
You definitely want to push the tow/haul button. The button will lock out 4th gear. It has no other effect. So, it will shift 1-2, then 2-3, and then hold. But, the only way to keep it from doing a 3-2 down shift is to modify the govenor table curve in the computer or loosten up the TV cable just until the point to where it won't downshift at wide open throtle. The danger of doing this though is that your tranny could start slipping because of the lower associated line pressure with the looser cable. I wouldn't try this on a stock tranny. If you have a built tranny, it will likely be no problem.

The best way would be to modify the govenor curve in the ECU table and command 3rd gear to lock under wide open throttle. That way you could be in 3rd gear with the torque converter locked at around 20 mph and just stomp it from there and do a 20-120 mph pull, all in 3rd gear. It would give you a 1500 rpm - 6000 rpm pull. You will need software to do this though....
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My truck is pure stock (except for a K&N drop-in air filter, don't really considerit a Mod).

You statement means that I would need to get a SCT with a Tune that modifies the ECU. That also means that if I am going to buy an SCT I might as well get the Tune to go with it.

That then Demands two sets of Pulls, one with the mod to suppress the shift and one after I flash to the Performance Tune.

The only individuals that I believe I could trust for this would either be DC or Roe.

So this is how it all starts..... Simply wanting to get an honest pull on a Dyno and that Requires/Demands getting a performance tune to acomplish a non-performance Pull.

I think it is a Conspiracy!!!! :) :) :) :)
 
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razorbackfan said:
Some shops with dyno's have the software to lock your torque converter and include this in the price of the pulls.
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Thanks Jeff, I will make sure to ask the local shops here in VA, if not that only leaves the SCT. :)


Not happy about spending that much money just to get an honest pull... :(
 
Chief-

We use a Mustang style loading dyno and this is all you have to do:

Engage the Tow/Haul mode to lock out O/D (4th).

With the dyno in Load/Hold mode, take the truck up to 3800 r.p.m. in "Drive" then, at the operator's signal, you floor it and he releases Load/Hold button on the dyno. Note- The 3800 is just a guesstimate as I forget how high you need to go so the tranny won't kickdown into second with a pure stock truck with stock programming. 3800 should be fine, if it does kickdown, go a bit higher the next time before you floor it. The idea here is to get the revs/speed high enough so it won't kickdown...

When it reaches 125 m.p.h. (max in 3rd) or if he gives you the signal to quit before it reaches 125, lift the throttle and (in any case) DO NOT hit the brakes. That is all there is to it.

That is one way to do a standard pull and keeps it straight forward. It will give you Max TQ and Max H.P. numbers (which I believe is all you are after at this point) without e.c.u./tranny or tranny cable mods being required.

If you want more info than that from your pull(s), you will have to change a few things so the tranny won't kick down, as WOT indicates.


Ronnie
 
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rottenronnie said:
Chief-

We use a Mustang style loading dyno and this is all you have to do:

Engage the Tow/Haul mode to lock out O/D (4th).

With the dyno in Load/Hold mode, take the truck up to 3800 r.p.m. in "Drive" then, at the operator's signal, you floor it and he releases Load/Hold button on the dyno.

When it reaches 125 m.p.h. (max in 3rd) or if he gives you the signal to quit before it reaches 125, lift the throttle and (in any case) DO NOT hit the brakes. That is all there is to it.

But that is one way to do a standard pull and keeps it straight forward. It will give you Max TQ and Max H.P. numbers (which I believe is all you are after at this point) without e.c.u./tranny or tranny cable mods being required.

If you want more info than that from your pull(s), you will have to change a few things so the tranny won't kick down, as WOT indicates.


Ronnie
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Thanks Ronnie, that is about as simple as it gets, and saves me money as well.

Why does it not suprise me that you would have the answer.. :)
 
The only problem with the 3800-4000 then stomp it method is that you don't get any values below that rpm. So, if you are stock, you will basically get a 4000-5700rpm pull. Plus, your torque converter won't be locked, so you will have some efficiency losses there (your indicated hp will be lower). But, like Ronnie says, it won't cost you anything....
 
Do the run in either Tow/Haul mode or you can disconnect the kick down cable. That is what Roe recommended to me. If you are just getting a run just to see where your numbers are then don't nuke it out. Just go to a local shop and watch them hook it up. They know how to do it how to strap it down. Even on the same dyno your numbers will vary from pull to pull.

DTP racing in Chesapeake is who installed my turbo and have done lots of runs for me and Jrgnd. Just get 3 runs and see where you stand. Then when you get an SCT pay the extra cash or get them to cut a deal to get some before and after runs.
 
FlyingLow said:
Do the run in either Tow/Haul mode or you can disconnect the kick down cable. That is what Roe recommended to me. If you are just getting a run just to see where your numbers are then don't nuke it out. Just go to a local shop and watch them hook it up. They know how to do it how to strap it down. Even on the same dyno your numbers will vary from pull to pull.

DTP racing in Chesapeake is who installed my turbo and have done lots of runs for me and Jrgnd. Just get 3 runs and see where you stand. Then when you get an SCT pay the extra cash or get them to cut a deal to get some before and after runs.
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Thanks for the Info!

I had heard about them a couple of months ago and actually drove over to try and locate them, with no luck (did it without a map and from memory, always a mistake with me). Actually printed out the address this time.

I will give them a call this week and set up an apointment. What days would you be avail to meet up as you suggested?

Thanks again, look forward to seeing you...
 
FlyingLow said:
I'm still on leave all week so anytime is good for me.
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I am going to be working close to there this week. I will call or drop by and get an apointment and let you know. As soon as I get it set up I will post here and also send you a PM with my Phone # so we can talk and GTG.
 
Went to see the shop that FlyingLow suggested. I am going to have the Dyno Pull done on Thursday. Will make sure I post all the Info on my Base Line.

FlyingLow -- PM sent with my Cell Phone # if you want to meet up.. :)
 
farm out:rock: right arm :burnout:
 
Went to the "Torture Booth" today and got what I think was the "Honest Pull" I have been looking for. Tow/Haul Button pressed to keep it from going into 4th gear. Cable Disconnected to keep it from "Kicking Down" from 3rd to 2nd. Did NOT change gears during the Pull. A/F Readings.

Not Bad for a Pure Stock QC

3 Pulls No Aborts.

Horse Power 447.5
Torque 472 Ft Lbs
Air/Fuel 10:1 (Tail Pipe Clip On)


Temperature 86 Degrees
Humidity 53 Percent
Pressure 29.89 inches
Dew Point 67 Degrees
Elevation 12 Ft above Sea Level

Photobuckte Link to the Graph
 
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Da1Chief said:
Went to the "Torture Booth" today and got what I think was the "Honest Pull" I have been looking for. Tow/Haul Button pressed to keep it from going into 4th gear. Cable Disconnected to keep it from "Kicking Down" from 3rd to 2nd. Did NOT change gears during the Pull. A/F Readings.

Not Bad for a Pure Stock QC

3 Pulls No Aborts.

Horse Power 447.5
Torque 472 Ft Lbs
Air/Fuel 10:1 (Tail Pipe Clip On)


Temperature 86 Degrees
Humidity 53 Percent
Pressure 29.89 inches
Dew Point 67 Degrees
Elevation 12 Ft above Sea Level

Photobuckte Link to the Graph
Click to expand...

Those are VERY GOOD power numbers. What kind of dyno was it??
The A/F is rich and that can be solved with a performance flash.
Those kind of power numbers would be 475 (wheel) behind a manual tranny...
 
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Da1Chief said:
Went to the "Torture Booth" today and got what I think was the "Honest Pull" I have been looking for. Tow/Haul Button pressed to keep it from going into 4th gear. Cable Disconnected to keep it from "Kicking Down" from 3rd to 2nd. Did NOT change gears during the Pull. A/F Readings.

Not Bad for a Pure Stock QC

3 Pulls No Aborts.

Horse Power 447.5
Torque 472 Ft Lbs
Air/Fuel 10:1 (Tail Pipe Clip On)


Temperature 86 Degrees
Humidity 53 Percent
Pressure 29.89 inches
Dew Point 67 Degrees
Elevation 12 Ft above Sea Level

Photobuckte Link to the Graph
Click to expand...
:rock: :rock: :rock: :rock: :burnout: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats: :congrats:
 
Brand name of the Dyno is "Dyno Dynamics" it is a Mustang Style Dyno..

Yea, the guy was impressed that it made that power running that rich. He started to hint about a performance tune until I told him that would be a DC or Roe only mission... :)
 
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