how to hot rod a 4bt-3.9 cummins ?

[evldsl]

Does anyone know how to get more then the stock 105 hp out of a cummins 4BT-3. 9 ex bread truck engine?

 

[EMD-Run8]

If its got an inline pump, it should take p7100 torque plates. If its a rotary, check TST's website.

 

[DogDiesel]

4BT HP UpRate

First, if it is CPL 858 (likely is), it will be rotary IJ pump.

--you'll need a turbo,

--injector tips

--governor spring kit

--intercooler to mate with turbo/settings

--ear-plugs and sound deading mat

To my knowledge, no one sells a kit to uprate to certain HP levels for the 4BT. Hopefully, you can find someone who has did the HP you want and will let you mirror their success and give you tips. While I have heard a lot of conjecture, lot of theory and could-be's on this topic, I have seen no actual postings of dyno ratings, component listings on doing more than installing different turbochargers, intercoolers and govenor springs. And the seat of the pants difference. Someone may have changed injector tips, but I do not remember reading about it.

Another method is find the CPL of a higher HP engine, find the specifications and change the components that differ from CPL 858, like mentioned above.

I'd caution that any uprate beyond 120 HP will require intercool and cooling enhancements.

What's this HP needed for?

Wayne



Call or email Piers, hopefully you may get the info you desire.

Does anyone know how to get more then the stock 105 hp out of a cummins 4BT-3. 9 ex bread truck engine?

 

[blacksheepdiesel]

bellyscraper,



A 190hp marine version of the 4BT was and maybe still is available. The parts for it (injectors, injection pump parts, etc. ) could be helpful.



BTW, just what the heck are you scraping your belly on?



Trent