Yesterday I was driving on the freeway, and next to me there was a semi truck with a flatbed trailer. On the flatbed there was a wrecked semi tractor; it was so wrecked that I couldn't tell what brand it was. I could, however, see the engine. It was an inline 6 (probably a Cummins, I'd imagine) and it had compound twins on it. They did NOT look new. Do they come from the factory like this, or did someone decide to upgrade their rig?

 

I got pics somewhere of a factory set of Cummins twins on a old PeterBuilt, I dont know when they stopped makin em.

 

we have too kw's with 3406 cats and there stock with twins.i think one is around 600 hp and the other is 550 hp.

 

i had a 1982 359 pete with a 475 twin tubro. i think they made them 2 yrs as a proto type
Clark

 

Lots of the newer Cats have compound turbos on them-- I think the ACERT C15s have them and maybe some others.

Those twins are setup for maximum spoolup to help reduce emissions.

jh

 

2002 to now CAT Accert engines use compound turbos for emissons.
Gutless wonders if you ask me.

Cummins had a compound turbo engine but there piles of junk so they stuck with the single.

Nick.

 

C12 and C15 ACERT Cats have them. Not for power, emissions solely. I don't know about the maximum spoolup thing either, my 00 14.0L Detroit sure seemed like it would spool quicker than the 06 C15 I drive now, and that one didn't smoke at all. This one will let out a cloud every now and then, but most of the time it's a marginal haze.

 

IIRC back in the late '70s Cummins had a twin turbo setup. Believe it was a NTC-450 or 475.

MikeyB

 

My new 08 KW at work has twins on it...iirc its a Cat C11;also has a DPF and 7" stack. However, driving around with 80,000lbs with a seriously detuned (by work) engine really isnt very much fun.

 

This is a pic of Accert twins that I took in '04

 

That is totally it. They weren't painted, but those are they. They really didn't seem very big for the size of the engine. Common sense says otherwise, but they didn't LOOK too big to put on our trucks.

 

In the early 70's I used to drive a Mack R700 tow truck that had a 903 Cummins with twin turbo's.

We also had Double Deck transit coaches made by Neoplan powered with 903 Cummins with twins.

 

You guys hit on the head. They are solely for emmisions and in my opion the suck power from the engine. We hurried and got some of the last pre-emissions engine trucks while we could. Then the last truck was a cumins, almost a 1/2 of a day better fuel consumption and better power. I guess that what happens when you take a 475 cat and turn it up to get 500 hp and take a 600 cumins and turn it down to 525.

 

I know they still made a 475 twin cummins in 86 because a buddy of mine has one with a factory 5x4 trans and when he got it stock it was very weak but with a few changes about 5k it turned into a beast. had no problem passing a KTA 600. these new accert motors are junk right from the get go, but that is what cat had to do because on all pre-emmision motor they had to pay a fine to EPA for pollution.

 

I ran a kt 450 back when with a few minor tweaks it put down close to 600hp to the ground short on legs but it would pull hills only ever had 1 truck pass me , over fueled cat 3408!!!!!!!!!!!