I know there are a lot of truck drivers and diesel mechanics on here, so I thought I'd ask if any of you have been around the new Cat ACERT engines. I read an article about them last winter and thought it would be fun to get to drive one. Well, this summer I got the chance. It was a 475 HP in a '04 Pete with an 18spd. Talk about fun. It did take a long time to get use to since it runs at such a low RPM, but once I got it figured out it was really fun to drive. Unfortunatly I only drove it about 600 miles and it took about 400 miles to get figured out where it really ran the best. For those who don't know the new Cat ACERT engines have twin turbos and you run them between 1200 and 1500 RPM. It doesn't take long to rap up and shift to the next gear. I was really impressed with it. It had no problem keeping up with a 550 Cat. It did take some getting use to running about 30 psi of boost all the time. After I got it figured out I could set the cruise so I was running about 1350 RPM and it basically could hold it no problem. Even going up hills if you were about to the top and down to about 1100 RPM it would pull over no problem with out having to down shift. It was just an experience I really enjoyed and I was just wondering if anybody else has been around them.

 

What if anything were you hauling?

 

do you have to run a lower rpm to help build more heat?? I've heard lots of bad things about the bridge and ACERT motors.

 

I was running bobtail the first 300 miles, then coming back I had a Gleaner combine and a grain cart behind me. I'm not sure of my weight, except that it was under 80,000. I think it was only around 70,000, but not sure. As for why it runs at such a low rpm, I'm not an engineer or diesel mechanic so I'm not sure. I just know that is where it makes all the power. It might have to do with the twin turbos. I've also heard that if you don't keep it in the "sweet spot" you're fuel milage drops fast. The guy who owned it said he didn't like it at first, because he was running it up to about 1800 rpm before shifting like his old truck. Then he learned to keep it down lower and he is really impressed. The advantage I see to running lower rpms is you save on engine wear.

 

Old habits are hard to break. Ever since the drive by wire has hit the big truck market we've been keeping are RPM's at or under 1500. The old mechanical motors were making their power at a higher RPM than these new electronic ones. Lot of guys were so use to running the old mechanicals up into the high teens before shifting which doesn't work well with the new electronic motors. My first electric Kitty (3406E) made its most torque from 1350-1500. Running much over those RPM's just didn't do much other than make more noise and feet better. I currently have the new Mercedes which they tell you in your owners booklet, CD & cassette along with the book to not exceed that magic 1500 number. Infact they also state start up/warmup time to be enough once you have did your walk around! Cooling down also is shortened consideralbly. The manufacturers are trying to cut idle time down in the name of MPG's which always raises the question about longevity. I still prefer the old mechanical motors, but as with everything else one must move along.

 

my paw has a 04 peterbuilt with the new twin turbo cat and it only goes up to 30 psi of boost on a hard take off but going 70 mph down the road it only makes 3-10 psi of boost. and you only have to use the clutch on take off but after that you dont have to and he likes that alot.

 

Thats the way all trucks are, with the clutch. Except for the volvo transmission I believe, but I wouldn't own one of those anyways. I have been wanting to take a spin in a new acert motor, but I have heard of so many problems with them. The old mechanical motors are cool, but are on there way out. Gonna run ol' thumper as long as I can though.

 

Any big rig I've drove you didn't have to use the clutch to shift. Then again, if you do use the clutch you have to double clutch, which is an art I haven't learned. The ACERT engines run lower than even the 3406E. I drove one of them this summer too, which was a 550. You had to run it up to about 1800 in the top gears for best performance. I also drove a truck with an old mechanical, and that was a nice pulling motor. It was a 425 turned up pretty good, don't know what it would dyno but guessing over 475. I think the 425 would actually lug better than the 550 HP 3406E, but I think the ACERT would lug even better. Then again I didn't put as many miles on the '04 so I'm not positive, I was impressed though. What problems have people heard of with the new ACERT motor? The only thing I wasn't sure about is overheating, since you are running two turbos. I know they are cooled through an intercooler on the first turbo then and air-to-air aftercooler after going through the second, but I can still see overheating with that much boost. It's kind of nice hearing from other people about this and I look forward to finding out more.

 

I have yet to really hear of one that has gone over 150k miles without a lot of problems. I was talking to a friend (wouldn't you know it) I forgot what fleet his is in, and they ordered 25 ACERT motors and they have 2 of them still going. Not sure on what kind of failure they are having, but paying out the cash for a new truck and having it sit in the shop. A pickup isn't as bad, it usually isn't a tool, but a truck is. I have a 3408, that is fueled. AI was gathering the pieces and was getting ready to have a set of marine pistons sent to be ceramic coated, and then fuel shot up. It was going to be an industrial TT, air-to air intercooled setup, shooting for 850 horse. But with fuel, I will probably park thumper and look into a ISX 565-600. But I'm guessing it to be at around 530 to the wheels in Denver. My dads old 3406B with cermaic coated pistons, marine injectors, ect. put down 519 in cheyanne. (sp) I know.