[Dale]

This is not intended to be a joke.

When you are at a rally or meet up with another owner of a coach of your type and weight do a drag race. As an alternative maybe we can poll our members and any that are on the road can time a zero to sixty time and report on the forum. Then you can compare yours.

You likely cannot compare performance to other coaches unless they are quite similar. Even if a coach such as your previous one weighs the same the engine may have a different torque curve or the transmission may have different gearing or the rear end ratio may be different. My first coach was a snail on acceleration and acceleration was almost non-existent at higher altitudes. But once it got the revs up in first gear it pulled strong and would catch and pass almost any other coach until it hit its top speed of about 72.

Add your coach information to the signature line. It helps with answers. If you haven’t yet done so weigh the coach. Not only will that help in evaluating answers it will help you use the proper air pressures for your tires. Without knowing your axle weights you do not know what tire pressures are correct.

[Herb]

Could be a boost problem and the CAC.

[Archived]

JD, if you want improved acceleration, make sure your transmission is not in the economy mode. There is a button marked “Mode” on your transmission pad. Some coaches (like mine) have the default set to economy mode and require the button to be pushed to shut it off (or rather, to engage the performance mode). On mine, a red light is illuminated when the performance mode is engaged. Others are the reverse, with the button pushed to engage Econ. In the performance mode, the transmisison will hold gears longer before shifting and will get you rolling into second at higher revs for better pickup.

You didn’t say what your prior Cummins powered coach was, but unless it was a bus it was likely quite a bit lighter weight than your Prevost. That could explain the difference you perceive. At around 50,000 pounds, the bus is simply not going to start moving much until your revs build enough to get the turbo going.

Without putting it on a dyno to test, observe how you accelerate compared with semi trucks. With my older 8v-92 coach I could rarely beat a semi from a stoplight, but with my Series 60 bus I can accelerate faster from a stop than a big truck about 85% of the time, even when towing a heavy car. If you are slower than most semi trucks, you may have a problem.

[Mike]

I agree with Tom … the CAC is in good condition ? You had CAC checked out in the pre-purchase inspection and it passed ?

So… with our former 2005 Marathon XL-II acceleration from dead stop was not anything to brag about. Just to get the 53 K lbs rolling off the line as turbo boost kicked in RPM came up then up shift to 2ad then 3ad steadly increased in speed.

I’am driving our current 2000 Marathon the same way just letting the engine, trans and turbo do the work. If you drive her hard the fuel economy will be awful.

AL

[Archived]

Our coach is an 04 and although it’s not a Prevost it has the same engine and transmission although there may be programing differences. Our coach was a real dog off the line and really came alive as the RPMs passed 1500. This made left turns in traffic a test of patience for following traffic and a bit exciting in the coach. This phenomena was far different from any truck I have driven.

Everything changed for the better after installing The Ugly Fix. Now our coach accelerates as I would expect any large vehicle to accelerate.

The Ugly Fix replaces the barometric pressure sensor and apparently fools the ECM into thinking the engine is at high altitude turning off the EGR system. In another thread Jon pointed out that this doesn’t always work depending upon ECM programing. It works on our coach.