Very slow acceleration until 2000 rpm then zoom, is this normal?

[jarmar]

I am quite new to the Dodge diesel world. When I step on it, say merging onto the Interstate, there is very slow acceleration until c. 2000 and then it takes off like a scared rabbit.



I am wondering if this is normal for a CTD?

 

[SRadke]

Paeak torque is 17-1800 rpm, that is where it should really start to pull. Below 1700, yea doggish.



-Scott

 

[jarmar]

Paeak torque is 17-1800 rpm,...

I will need to watch a little closer but it seems like closer to 2000. It seems like the truck is being held back by a huge rubber band and then suddenly it snaps and jumps ahead.



jr

 

[SRadke]

You know I really need to start editing these posts Two A's in peak... . rediculous



I've never driven a 600 but my poor little SO was like that. Didn't really get going till about 2100. I think it was because of the speed you're already rolling. When on a load dyno or pulling a trailer it got started earlier. Of course that was before TST sold me their product, she lights off a little sooner now



-Scott

 

[Blufrog]

Open up the air intake. I put on the AFE Pro 7 kit and what a difference it made, the whole rpm band is way more responsive. Mine seamed sluggish till around 2k rpm before and now does not feel that way. only mod is the AFE kit.

 

[oilburner]

My truck is the same.

It is because boost and air flow must increase before the ECM will allow more fuel flow to keep egt's and emissions within acceptable limits.

 

[jarmar]

OK, thanks for the explanations. Just wondered if something might not be quite right.



jr

 

[turboost]

On mine it feels like the turbo isn't spooling up till about 2k rpm. And when it does the remaining rpm goes by fast and before you know it your shifting again. I only have an exhaust. I think a chip would help alot by spooling the turbo up faster.

 

[EEdmondson]

Mine does the same. I almost clipped the rear corner of a car I was going around once.

 

[KD7GYJ]

I have a 600 and the turbo doesn't let loose until I hit around 2000+ RPM's. Then it throws you back into your seat and if your not watching where you're going, your running up the back of the car in front of you. It is really strong in 3rd on up. Second gear romps, but the gearing is so low, you don't have the speed.



Blair

 

[yogibear]

When Edge gets the Juice on the market that will change!! Mine comes on strong at 16-1700. I used to have to grab 5th when loaded and it got down to 1900, now I can back it down to 1700, and it comes back strong!

I know you are all PI$$ed at Edge, but they are having some issues with it, and want it to be perfect when they put it on the market. I don't know how it will compare in hp withe the TST, but mine is working great for towing. My dually weights 9800 full of fuel (165gal. ) and me in it (185#) and I'm getting 19-23+ mpg running 70-72 mph empty. Thats not including my 8 gal. water tank for the Snow water inj. system.



Larry

 

[jarmar]

Mine does the same. I almost clipped the rear corner of a car I was going around once.

Exactly, I thought maybe I was the only one. There have been times when it was almost a little scary.



I was thinking it would be smoother than it is. Perhaps there is nothing that can be done but caution.



jr

 

[GFritsch]

Yea--my 600 feels slow below 2,000 rpm and the BAM. I shift at about 1,800 rpm for economy. When I want quick speed I shift at about 2,500. Coming from a 94 It took a little getting used to. The 12 valve felt very strong at about 1,200 rpm.

 

[DCTECH]

There was a post on this a while ago, TSB 18-07-04 might apply to your vehicle if built from 12-10-03 through 2-2-04 and between engine #57130285 to 57149668. Covers flat spot on acceleration between1500-2000 rpm. Engine controller needs reflashing to fix. This reflash will also give lock up torque convertor clutch when manual 2nd gear is selected on auto trans models. I have done several of these flashes and cured problem.

 

[klenger]

Keep in mind that while the engine reaches max torque at 1600 RPM, HP increases linearly almost up to redline. As diesel owners, we get so wrapped up in torque discussions that we seem to forget that HP is part of the performance equation.

 

[MCornwell]

As mentioned earlier in the thread its so the EPA stays half way happy... and



for smoke control. If fuel came on strong from idle with these little 9scm



turbos, the heavy towers out there would be popin turbos and drivelines on



DCs dime... smokin like a train untill 1500rpms :-laf -my take on it.



-Mitch

 

[EBottema]

Welcome to the diesel world powered by RPM

 

[jarmar]

There was a post on this a while ago, TSB 18-07-04 might apply to your vehicle if built from 12-10-03 through 2-2-04 and between engine #57130285 to 57149668. Covers flat spot on acceleration between1500-2000 rpm...

I think this is worth a followup. I took to the dealer for this problem and other service and was told that there were no TSBs applicable to my truck. Yet it falls within the parameters you mentioned above.



jr

 

[OT-OF-HERE!!]

I had a box on mine for a heart beat and it went away totally. It would patch out nicely when before it was almost as you described. Mine wouldn't pull hard until about 1500 rpm. Also if you haven't pulled anything heavy yet you need to do it. The sooner after initial breakin the better for mpgs and for power. It makes a major difference,... you'll see.

 

[opjohnny]

You don't get all 600 ft-lbs in low gear according to a dyno chart for the engine from cummins. Low gear is limited to 450. I am not sure if this applies to both trannies.