The 4.5 or as it is better known as the iSB4.5 is basically the iSB6.7 minus 2 cylinders so most Dodge Ram 6.7 aftermarket performance parts fit perfectly making this engine unique in strength and performance potential.
Cummins build these 4.5 around the world under a few names like the iSDE180-30 iSB4.5lt and B4.5 Common Rail Diesel engines in USA, Brazil, China and the UK.
These are not a 4BT or 6BT these are a real Common Rail beast, neither are they just a B-series block bored out to 4500cc these are a complete redesign but having said that they do owe their basic design to the B-series. Like the B-series they are not a wet sleeve this saves a lot on weight and mass as the casting doesn’t need to be as heavy cooling is more efficient as well with excellent coolant gallery design.
The standard iSB4.5 are 183 HP and 650 nm is governed to 2500rpm this is far too low for most applications and our 4×4 client base is for the most part interested in motorsport or at least playing in the Bush with higher RPM and excessive power. The possibilities of more power is enormous for the 4.5 and these have the build to become bitumen shredding torque monsters, to this end we have developed a few options from 220hp to 300hp governed to 3400rpm in the CM2150 ECU, and a motorsport model with 350RWHP is on the way.
The basic 4.5lt engine is a 4cyl 107mm bore 124mm stroke with a 16 valve head and central vertical direct injection turbocharged high pressure common rail engine with 17.3:1 compression ratio no glow plugs. The main design is based on the modern 6.7 truck engine, with rear timing gears so they do weigh in at 390kg with the SAE#2or 3 housing and flywheel, so don’t rest it on ya toes, but this is close to the td4.2 or Land Cruiser engines, as most applications will be without the SAE housing’s heavy flywheel and air compressor this drops around 40kg.
The 4 valves per cylinder design gives a much higher flow potential to the head however the plenum like all Cummins heads could do with some modification for extreme power, but this is just standard work for any high-performance Cummins build as such we have started to design a high flow head and plenum.
As the pistons, con-rods, crank design along with most internal parts are from the 6.7 with rated standard torque of 1100nm there is more than adequate inbuilt strength there and to keep this all that bit stiffer they have added a steel girdle in the skirt. Still for race builds we would go with race rods and pistons Mahle or CP-Corrillo and a ballistic girdle that incorporates main cap securing ARP studs but there are lots of go-fast parts on the market for the Dodge Ram 6.7 that will fit right in.
The timing is via a straight cut geared drive train at the rear of the engine this drives the Cam, fuel pump and accessory gear like an on-board air-compressor and power steering pump that is standard. we can also supply a new Ballistic girdle that ties the main crank caps and skirt together with 12mm ARP studs.
Timing gears are encased by the front of the cast alloy SAE flywheel housing or transmission adaptor plate gear noise is reduced vastly compared to the old front gears of the B series, these used a thin steel cover that acted like an acoustic amplifier. Also, with full gear driven valve timing no more timing belts or chains to be concerned with.
Since we first introduced the iSB4.5 into the 4×4 industry in 2017 we are very pleased to see how far they have come much of it due to the work of the team of Cummins Engineers at GLABE, we have developed the most extensive range of conversion components for the iSB4.5 from adaptor systems to our latest project the 350HP 1100nm Gen2-4.5.
And the latest fuel figures for a GU patrol towing a camper are very impressive, from Diesel conversions Australia at 11.72lt per 100klm, although most are between 11/100klm and 14/100klm.

On the High-Performance side, we have spent some time developing a prototype 13mm plunger P-pump 4.5 engine eliminating the Common rail completely with a triple compounding turbo setup for full race trucks, this engine is currently being evaluated for further development and eventual sale as a kit for experienced Engine builders.