Cat Twin turbos

[csevers]

We just got a new Freightshaker with a C13 Cat acert engine in it with twins on it with a coolant to air heat exchanger just before the intercooler. It looks pretty good, I test drove it and it is a DOG due to torque tailering, empty it spools about 1800 and govs at 2200. I sure hope it has more go under load. I wonder how why Cat was the first to go this route to try to make Emission standards?



Craig

 

[bmoeller]

How many HP is the engine you have? What gearing?



The EPA doesn't really give them a choice to put that crap on the engines.



With it being a dog, I wouldn't bet on it performing any better with a load on it. Mack has the same problem on the 355/380hp MaxiCruise engines that I have used in lease and demo trucks. By the time the engine decides to kick in the extra ponies, it is already to late to overcome the load. It works fine empty, and can feel the power come like my Ram does with the #10 plate in it.

 

[CFast]

Cat chose that because "caterpillar doesn't eat it's own waste". ie EGR. They had to lower NOX and upping the boost and adding a Caty conv. were how they chose to do it. BE glad you didn't get a S60 EGR.

 

[csevers]

Oh I am totally against EGR in any form on any vehicle that is diesel. No arguement there. Every one is the shop was just surprised to see twins. They also made fun of me asking if I was going to order the parts from cat for my truck... . lol



It was a 435 hp we don't get the "big hp" in a lease fleet, the morons would really break stuff then.



Craig

 

[BigYellowIron]

the turbos are not the only difference, you should take a look under the valve covers!!!



Adam

 

[GTop]

I thought the C13 makes its peak torque at 1200. Its a waste of fuel to rev high. All the power is made down low. Hopefully the C13 wont have the head gasket and turbo problems that plagued the C12.

 

[CPjMech]

All the PT and HP ratings are the same on the new C11,C13 & C15 as the old C-10, C-12 & C-15. There was some cold start up timing/smoke issues at first but seem to be OK now. We haven't seen any head gasket probs yet, the head is now a crossflow design. The turbos should hold up better since they are only turning half the RPM. The only prob we've seen so far is air comps, they are now a single cyl instead of 2 cyl. We changed out about 55 of them at the KW factory 3 weeks ago with an updated design. What fun.

 

[CFast]

The meradeez use a single piston compressor and those build up air pretty fast. How about the CAT's?

 

[CPjMech]

All the CAT's are using a single cyl air comp made by Bendix. They do build air faster than the old ones.

 

[Will24]

Twins on a little guy? Damn, I know the new C18 ACERT engine has twins, didn't know they were putting them on the smaller ones too!





-Will

 

[fbaurley]

If what ive heard is correct, the cats have variable valve timing, on the intake stroke they momentarily open the exhaust valve to pull some exhaust gas back in, therefore you get the same effect as EGR , but you arent running it throught the intake. The second turbo is to help pull the air thoeught tthe enginee, due to the fact that open the exhaust valve on intake kinda screws up the air flow throught the engine. The heat exchanger, before the air to air is to cool the extremely hot air after its been heated and com pressed by the two turbos. The end result is really close to an egr engine, and is actually more complex, but you arent running crap thorought the intake. I belive the variable valve timing is controlled similar to a jake brake operation by a soleniod on the valve crossheads?

 

[JohnE]

C-9 ACERT uses a single turbo.

Don't know much about the engine yet. I haven't had a chance to play with the electron box to see what goes on from the ECM side.



Expect a big derate until coolant temp is up. These engines must run warm.

 

[R.E. Miller]

One of the main reasons for CAT's using the twins is due to emissions and the fact that they wanted to run the Holset version of the VGT turbo. Cummins would never have that, so the staged turbo design is the next best idea for what they are trying to accomplish.

Russell

 

[CPjMech]

The C7 & C9 both use single turbos, very little changes to ECM programing from the older 3126E's, they have added piolet injection to all engines. C11, C13 & C15 all use twins. The ACERT (11,13,15) engines are only using the variable valve actuaters (VVA's) on the intake valves, but it does work the same as a Jake Brake. From what I've seen they are only opening the intake valve earlier/and more duration on overlap to let the 45-55 PSI boost blow the exhaust out of the cyl and pack more fresh air in. They don't work all the time, only under certain conditions. I don't see how you can have any EGR action by opening the exh valve when you have 45-55 PSI of boost on the intake side + all the cyl PSI.

 

[MMiller]

I've seen a couple of C15's acerts at 500 horse. The right side is real busy, as is under the valve cover. I also noticed the yellow paint on the second turbo compressor housing was turning brown from the heat. I wonder what that will do to the longevity of the secondary turbo. Usually from what I see and work on the paint stays on the compressor housing and stays yellow, doesn't get burnt off.



Michael

 

[KIseminger]

Kind of aside from Cat's; I am a firefighter and we just speced a Pierce with a 515hp Detroit. Has anyone had much experience with this motor? Good? Garbage? I am assuming it has all the emmisions junk on it. We've had Detroits in the past and had good luck.

 

[fbaurley]

I have heard rumors that earliy on some of the Cats had the turbos get hot enought o actually bubble paint on truck hoods. This was heard from a cummins distributor, so take it with a grain of salt. Most like to emphasize the Negative about there competitors. I saw, a cut away Acert, and Talked to a Rep at the Mid america truck show this weekend, and stand corrected on some of my above statements. The variable valve timing is on the Intake valve, High boost, 45 to 50 psi as stated above, and the engines have a split/ pilot injection, but the c 13 and c15 still use the Meui, mecancial unit injectors with electronic metering. alla Acert engines , now have a catalytic convertor/ muffler on them also, to help meet emissions