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Old 03-20-2005, 04:56 PM   #1
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Has anybody tried to reprogram the 8.1 chip for more horsepower and torque? I pull an Explorer as toad and could always use more power.

Also curious if anybody considers the final overdrive shift-point at 55 mph too high under light loads. I feel that the transmission should shift earlier when lightly loaded. As I accelerate, top gear will not shift until I achieve 55 mph. If I slow down after that point below 55 mph, (like 50 mph), it will stay in the top gear unless under heavy load.

I like 50-55 mph cruising, but the current setup forces me go beyond my target and reach 55 before it will shift. I then back down a little to slow the engine rpm and reduce the rpm noise.

I watched an advertisement for a tool that reprograms the OEM chips for power curves and can also change the transmission shift characteristics. It does not mention motorhome applications, but I do intend to call the manufacturer to discuss my situation.

I am looking forward any comments, experiences and above all your warnings.
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Old 03-20-2005, 04:56 PM   #2
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Has anybody tried to reprogram the 8.1 chip for more horsepower and torque? I pull an Explorer as toad and could always use more power.

Also curious if anybody considers the final overdrive shift-point at 55 mph too high under light loads. I feel that the transmission should shift earlier when lightly loaded. As I accelerate, top gear will not shift until I achieve 55 mph. If I slow down after that point below 55 mph, (like 50 mph), it will stay in the top gear unless under heavy load.

I like 50-55 mph cruising, but the current setup forces me go beyond my target and reach 55 before it will shift. I then back down a little to slow the engine rpm and reduce the rpm noise.

I watched an advertisement for a tool that reprograms the OEM chips for power curves and can also change the transmission shift characteristics. It does not mention motorhome applications, but I do intend to call the manufacturer to discuss my situation.

I am looking forward any comments, experiences and above all your warnings.
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Old 03-23-2005, 06:05 AM   #3
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Dale, I have the same situation with my 2005 W-24, 8.1 and would like a lower shift point for high gear. My driving habits must be like yours. I have not done much research other that ask Workhorse and of course their answer was that I shouldn't change anything. Please post whatever you find... Thanks...
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Old 03-23-2005, 07:06 AM   #4
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You can check with an Allison shop about changing the shift points. I know they do it for the big 6-speed Allisons (MH 3000) and have several shift profiles to choose from. Might have something for the 1000 tranny also. And if I remember correctly, the W24 uses a 2000 series tranny.

I don't think you can move overdrive more than a 3-4 mph lower, though, especially with the extra wight of the W24. Maybe it is already set higher than a W22?

In any case, if you reprogram you cannot exceed the torque and HP ratings of the Allison tranny. For the 1000, that is 545 ft lbs and 375 hp. A stock 8.1 is under that, though.
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Old 03-24-2005, 04:41 PM   #5
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I also posted this issue on another site. I see from both posts that there are others that feel the same way I do about the shift point. I will try to find out more from Allison and let you know anything I learn.
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Old 03-24-2005, 06:31 PM   #6
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I don't believe that you'll get Workhorse to change the shift pattern.

Personally I wish the Allison would shift earlier while going slow between 48 to 53 MPH. Sometimes waiting to get to 55 you can break a 50 MPH speed limit just to slow your RPM and save fuel.

Now I do know that once I'm in 5th I can go as slow at 49 MPH while straight and level and the tranny won't shift down to 4th. I just lightly feather the throttle just to see how slow I can go without a shift. 49 is about it, and it'll run about 1800 RPM in 5th but not much lower before downshifting.

Do I think that I need to get an updated shift pattern from WCC or Allison? Probably not. I'm used to driving the motorhome the way it is.
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Old 03-25-2005, 04:27 AM   #7
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Dale read this thread,

Reprograming the chip on W22 8.1L?

Look at my three post's on this thread, I referance a "sweet spot"
I dont think the engine & trans combo we all have likes to be at the speeds you like to drive.
This thread was on a different forum, I would like some observations from the guys on this forum.
Driver, what are your thoughts.

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Old 03-25-2005, 04:51 AM   #8
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<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Gregg:
Driver, what are your thoughts. </div></BLOCKQUOTE>Hi Gregg, Thanks for sharing your previous with us but the link you provided simply brings us right back here.

I'm looking forward to working on this with the posters in the forum.
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Old 03-25-2005, 05:31 AM   #9
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I will start calling Allison dealers today to see if anybody has a recommendation. Will let you know what I find out.
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Old 03-25-2005, 01:42 PM   #10
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Well, I have spent the day visiting and calling experts on the transmission issues:

Went Aamco Transmission - they knew nothing about the unit

GM dealers (two of them) they did not think anything could be done and had no suggestions

Allision Transmission dealers - two of them - nothing can be done to reprogram the transmission.

Local truck transmission experts - nothing can be done by them expept to put the OEM programming back in.

Hypertech - manufacturers performance chips and programers - never tested on a motorhome so they can not recommend their product for this application. Although I noticed they sell it for GM 8.1 with Allison, so I wonder why this won't work for us. Check out this link and let me know what you think.

http://www.hypertech.com/programmer.html

Banks Engineering - Nothing can be done to reprogram the transmission. For the power needs, they recommended their exhaust kit which provides aprox 50 more HP and 58 lbs torque - I think we all know about these upgrades which work well - however expensive.

All that is left is to call Allison themselves.

It looks like I am out of luck with the transmission - too bad since we all feel the same.
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Old 03-25-2005, 02:16 PM   #11
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<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dale Smith:
.... too bad since we all feel the same. </div></BLOCKQUOTE>Wellllll .. Not exactly. In 2001 the initial W20s were programmed to downshift to the basement in order to pick up speed when negotiating a grade.

Workhorse received numerous suggestions that it's not really necessary to go from 5th to 2nd just to pick up speed and they agreed and now we see a better shifting transmission that down shifts from 5 to 4 to 3 to 2. That's all I ever wanted at any time. I had both an 01 and now the 03.

The way the Allison shifts right now is just fine and I don't think you're going to convince engineering at WCC that the shift point needs to be set any lower than 55.

WCC wants the MH to pull as many revs as it can before shifting because in most cases the MH is under load and more revs equals more cooling. Slow that process down any and you could have a lot of problems with engines over heating.

I think that's a safe bet on why the tranny shift the way does.

You sure did cover a lot of bases today.
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Old 03-25-2005, 02:53 PM   #12
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Hi Driver,

I understand your points about the "heat concerns" and "usually under a load". I consider myself to be very conservative on the throttle and find myself traveling comfortably around 50 mph often. I wish that the transmission would shift sooner when there is very little load. It will not shift sooner even if coasting downhill!

I suppose that the shift programming is the best compromise and the engineers know their business. It is not a big problem anyway, merely a driver preference issue. (no pun intended Driver!)

Thank you, as usual, for your welcome comments.
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Old 03-26-2005, 03:55 AM   #13
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<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Hypertech - manufacturers performance chips and programers - never tested on a motorhome so they can not recommend their product for this application. Although I noticed they sell it for GM 8.1 with Allison, so I wonder why this won't work for us. Check out this link and let me know what you think.
</div></BLOCKQUOTE>

The reason it MAY not work is the difference in rear axle gear ratio and the total weight of the unit, compared to a pick-up truck or van. The W20/W22 chassis uses axle ratio 5.38 with 22.5 inch wheels and 4.88 with 19.5's. A 4.78 is optional with either. The W24 uses a 5.86 and the P32 either 4.56 or 4.63, depending on GVWR. These different rear axles substantially can alter the loads on the engine at different RPMs and require a different shift profile. The vans and pick-ups use rear axle ratios in the range of 3.73-4.11 and of course the max load (weight) is far less than a W22 or W24.

There may also be programming differences in the original 8.1L ECM chip for the Workhorse versus the GM pick-up application for the same engine. Electronic control engines are typically tailored to the specific application by chip programming changes, e.g the same engine block will be operated differently in a boat than a passenger car because the typical power demands are different. In the old days they used to put in different cams, valves or carburetors to handle different applications, but now they do it all via parameters in the engine control chip (now called a powertrain management system). Replacement chips mimic most of the original programming and alter some of the values to get a different performance profile. Until they study how the motorhome application of the 8.1L differs from the pick-up application, Hypertech won't know if there chip mimics the right chip values nor if their changes are improvements or actually hurt performance (or worse, overstress the powertrain and cause damage).
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Old 03-26-2005, 04:31 AM   #14
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Sorry about the mistake guys,
Heres the correct link, I'm curious to see how many others have discovered what I did.

http://www.woodalls.com/cforum/index...g/1/page/1.cfm
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