does anyone know why greyhound updated from ddec 2 to ddec3

[NJT 5573]

I found in DD records that they removed the ddec 2 and updated to ddec 3 on the greyhound fleet.Whats different? maybe fuel milage?

[rayshound]

Not sure of all the differences. There was some postings a few years back on all the stuff to replace to upgrade. The ddec3 and 4 are about the same. The ddec2 uses an Eprom the 3&4 is a down loadable brain. A few of the features is the two communications links for the latert electronic controlled transmissions like the eaton autoshift and allisons electronics.  Ray

[RTS/Daytona]

Ray

Maybe I'm wrong but - wasn't

DDEC 1 - Eprom  (non downloadable - chip replace only) (Luke has updated chips for N.J bus with slow pickup (no smoke feature) - before Federal standards were approved

DDEC 2 - Downloadable - First Federal Standard Compliant Version

DDEC 3&4 - very similar - More sensors - more function/features  - more user settable - downloadable

Pete RTS/Daytona

My RTS DDEC 2 - is cooled by fuel running thru a heat transfer plate mounted to the ddec

Not sure of all the differences. There was some postings a few years back on all the stuff to replace to upgrade. The ddec3 and 4 are about the same. The ddec2 uses an Eprom the 3&4 is a down loadable brain. A few of the features is the two communications links for the latert electronic controlled transmissions like the eaton autoshift and allisons electronics.  Ray

[rayshound]

Pete;
      You may be correct. I had talked with someone awhile back about upgrading his s-60 11L with a ddec 2 and he needed to go to a ddec3 or 4 to add a allison world. He got estimates in the thousands for the upgrade. Injectors, camshaft, gears, brain, wiring etc. He had said his ddec2 had an eprom and dd didn't have a program to run the allison world. I myself have an ATEC  HT- 748 that was on a ddec2 out of a 91 Eagle that the ATEC  brain has a Eprom and I do have a prom that supports a ddec 4 on my 12.7 S-60. So I'm not sure just a guess. I know to go from a ddec3 to a 4 it's a brain change, just not sure about going from a ddec2 to a 3.  On a 3 or 4 it is a large brain that bolts directly to the side of the block with 4 mini rubber mounts. No cooling plate. The ATEC brain mounts inside the bus but has the apperance of the size of a ddec2 brain which is about half the width and twice as tall.
                                                           Ray