I have just purchased a '05 Kodiak C5500 with the 6.6 Duramax. I am looking to increase hp and torque, but I have a 75 mph speed limiter. Anyone know how to remove it or a juice box of some sort that will? This thing will only run about 72-73. Everytime it get close to the 75 mark it starts shutting it down. Running 72-73 cross-country is a bummer. Sparky

Sparky,

The speed limiter is there for a reason. The manufacturer limits the speed based on the tire manufacturer's recommendation or drivetrain limitations.

I special ordered Michelin brand highway use tires that are restricted to 85, and a 4.44 differential, so that is where my speed limiter is set to (03 GMC C5500).

Your choice of factory ordered tires (rotation per mile) and differential ratio (engine and drivetrain RPM) limitations dictate the speed limiter settings from the factory, and may not be altered for safety or reliability reasons.

Changing the factory setting to a higher than recommended speed will void your tire or drivetrain warranties!

Not to mention cost a fortune, in extra fuel. Above 70 mph, the 6.6 guzzles lots and lots of fuel. The happy place for fuel economy with these trucks is below 60. - Grossing 20,450 pounds this trip, I averaged 10 mpg, if I kept the speed down, but the wide open Texas roads made it unsafe to go slow - trucks roaring around at 70.. So my fuel economy went to a low of 7.4.. not good at $2.19 a gallon.

Mylash

When this light went on, what were the circumstances (temp, first startup of the day, did you wait for the wait to start light to go out, etc.)? What type of brakes and engine do you have? Please be as detailed as possible. When you get the code, can you let me know what it was. Thanks
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Just found out BD Power is running a C5500 on the dyno today. A fix is coming soon.:grd:

BD has finished running their 05 Kodaik C5500. They tell me a box should be ready in the next few weeks. This box will remove the speed limiter plus give you some more power.

BD has finished running their 05 Kodaik C5500. They tell me a box should be ready in the next few weeks. This box will remove the speed limiter plus give you some more power.
Sparky, post a reply if you find more out about the speed limiter.

Mike

Will do!!

BD Power has the Kodiak C4500/C5500 boards in for more power and more. They should have the wiring harnesses done in the next few weeks to remove the speed limiter.

http://www.bd-power.com

Any more findings on the the speed limiter? I am still looking and have not found a solution? Any MD owners have a fix yet?

Mike

Not yet. I would call BD Power and talk to Christian.

http://www.bd-power.com/

Hello RadioFlyer03,

I saw your post about changing to a 4.44 differential, and wondered what your performance and mileage results are. What rpm are you turning going 65 mpg? What is your average fuel economy?

I just purchased a Gulf Stream Enduramax toy hauler model motorhome on a 2006 Kodiak chassis 22,000 lb upgrade with the '06 Duramax LLY engine. It is limited to 75 mph and has a 4.78 differential. At 65 mph I'm turning 2300 rpm which is way to high, and it only gets about 8.5 mpg.

I'm looking at changing it to a 4.44 differential. A 4.10 is also available, but I'm afraid of lossing the lower gear ratios with possibly not enough torque in the motor to pull me out of the hole.

Any information or recommendations would be appreciated.

Jack

I am still stock. Mine is a Jayco Seneca 35ft model. I am waiting for someone to come out with a mod that can remove the 75mph limiter before I change anything. I agree it is spinning too many rpm's. Sorry I did not have any better info for you.

http://www.pacificp.com/cgi-bin/cat/xceleratorlly.html?id=MLfmG2QX&mv_pc=1029

This will remove the speed limiter.

Thx!!!

The 4:78 is the only GM option on the 22000 and 26000 GVW trucks, but its only a matter of changing out the ring gear (roughly $1500 + labor and fluids). Don't think you want to go as low as 4:10, since any hill or head wind will have you out of OD and into high-revs. This will null any fuel mileage gains you may have by doing this change. The 4:44 may do better. I spec'd my truck in 02 for a 7,000 lb load and 18,000 lb trailer for speeds up to 75 MPH. I travel cross-country with roughly 26,000 lb gross weight and get between 9.5 and 10.5 MPG, while local unladen driving gives me 15.2 average. My revs can also be considered rather high when compared to the traditional over-the-road diesel tractors, but that's the draw back of a 8-cyl. short stroke motor over a 6-cyl. long stroke one. Torque has to come from somewhere.... if not from "displacement" then it has to develop in the higher RPM's. Simple physics.

Sorry if that is not the answers you are looking for, however you have to consider that although Man's laws can be broken, Nature's laws cannot.

Removing the speed limiter is risky....consider that many of the tires that are ordered on these trucks are rated at 65 or 75 MPH to prevent premature separation of the tread (alligators on the side of the road). You can spec. your truck with Michelin's all around, at an additional charge, and get a 86 MPH speed limiter setting (as I did). If you override the speed limiter, consider changing your rubber for ones that are rated for whatever speed you want to operate. At roughly $325.00 each, it does get expensive.

RF

Ive got 488s behind my lb7 4500. If I were you I would check into an edge with monitor, It sure helped my performance.

The Diablosport Predator will give you power and remove the limiter.

John