Caterpillar (6NZ) 3406E & C15 ACERT Engines 1.38
The 6NZ (first 3 numbers of the serial number) 3406E/C15 engine is, depending on who you speak to or read, is either the last of the 3406E series or the first of the C15 series. Either way, it is regarded as the best engine in the 3406 series. The 6NZ was the first of the mighty CAT’s to be rated at 600hp from the factory (even though it was still only 14.6L like the rest of the 3406 family).
The 6NZ differed from the previous 3406’s in that it had improved sealing for sumps and head gaskets, to name but a few modifications, which carried through to the first of the C15’s.
Even though the 6NZ had full ECM control on its operation, they were a pre-emissions engine. They were also the first of the CAT’s able to use an Automated Manual Transmission (AMT) so it can used with an Eaton UltraShift transmission if you wish.
This pack contains 4 6NZ 3406E (14.6L) engines rated from 525hp to 600hp and 3 C15 ACERT (15.2L) engines rated from 475hp to 580hp.
Engines use Kriechbaum’s ‘Original 3406E sounds for Fmod’ included.
Pack also includes Spicer SST20 Proshift gearboxes with 3 common diff ratios.
Technically speaking, the Spicer SST20 was a 20-speed ‘intergrated’ gearbox – 5-speed main plus 4 x ‘auxiliary’ (Low, Under, Direct, Over), usually controlled by a 4 position splitter switch on the gear-lever (can also be dash-mounted), however due to some of the higher ratios overlapping or being the same, it is usually used as a 15 or 16-speed (Low only being used in 1st and reverse gears):
1st – 1Low: 11.782
2nd – 1Under: 9.263
3rd – 1Direct: 7.47
4th – 1Over: 6.051
5th – 2U: 5.059
6th – 2D: 4.080
7th – 2O: 3.305
8th – 3U: 2.802
9th – 3D: 2.260
10th – 3O: 1.831
11th – 4U: 1.538
12th – 4D: 1.240
13th – 4O: 1.125
14th – 5D: 1.000
15th – 5O: 0.810