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Diesel Upgrades

How to Build a Reliable High Horsepower Diesel Truck

Vinny Himes



high horsepower diesel

Build a Reliable High Horsepower Diesel

There is a lot that goes into building a reliable high horse power diesel truck that can still tow at 750-800hp . First thing we need to cover is the fuel side of things. The stock fuel pump is junk for over 400 horse power.

high horsepower diesel

FASS 150gph (TD08150G) – CLICK TO VIEW

We are going to need to install a FASS Titanium 150 fuel system. This will provide plenty of fuel to support the Twin CP3 injection pumps required to run bigger injectors. A stock 5.9L Cummins has a single CP3 injection pump, but to run bigger injectors we have to add a second CP3 to keep the truck from dropping rail pressure during wide open throttle runs. You will know you are starving the rail whenever you get on the throttle hard and you get a violent popping and surging coming from the engine. That means the injection pump can’t keep up with the throttle demand.

View the ATS Duel Fueler

ATS Twin Fueler Pump Kit (7019002272) – CLICK TO VIEW

So basically the Fass is pulling extra fuel from the tank to feed the twin CP3’s and the Twin CP3’s are feeding the bigger injectors.

high horsepower cummins

Race Injectors 30LPM (0986435503-R1) – CLICK TO VIEW

Bigger injectors are required to make anything over 450 horse power. So in order to make 750+ horse power you are going to need at least a 150 horse set of 6 injectors.

Those three parts take care of the fuel system upgrades needed to make over 700 horse power.

High Horsepower Cummins

Compound Turbo Kit (IIS3GATPR) – CLICK TO VIEW

Next we have to address the air side of things. The stock turbo is only good for 450 horse power. You are going to need a lot of air to make over 750 horse power. To keep it from being laggy and make sure it’s still reliable for towing, I would recommend compound turbos and we will definitely make sure the small turbo is waste gated into the hot pipe which takes the waste energy and uses it to drive the big turbo. I prefer a none gated S300 series turbo off the manifold with an external gate dumping into the hot pipe between the small charger and the big charger. There’s absolutely no point in driving an S300 framed turbo more than 55 pounds of boost, open the gate around 50-55psi and let the little guy work easy, use the extra energy to drive an S400 framed charger closer to its full potential. Setting up compounds this way will lower EGT’s and greatly reduce cylinder pressure also known as drive pressures. Drive pressure is determined by measuring pressure created at the intake manifold as well as pressure measured at the exhaust manifold.

With an efficient single turbo setup drive pressures are usually around a 1:1 ratio. This means if we are measuring 30psi of boost at the intake manifold, we should in turn see around 30psi at the exhaust manifold, if not less. When you run a non gated compound turbo setup, the drive pressure to boost ratio can get out of hand very quickly. We have tested setups that were 3:1 and worse. Which means the truck was making 80psi at the intake manifold and pegging out a 100psi drive pressure gauge on the exhaust manifold side.The will cause bent rods, blown head gaskets and stress on the piston rings.

View the AFE Intercooler

Larger Intercooler AFE (46-20011) – CLICK TO VIEW

We need to make sure we free up the air system between the turbo chargers and the engine. The stock turbo doesn’t move much air but these compounds are going to move 3 times that amount of air and we need to make sure we can cool that charged air down before it is forced through the intake valves of the engine. The easiest way to cool down this excess air is by installing a larger intercooler and intercooler pipes. It increases the volume in the charge air system allowing the air more room and time to spread out and be cooled before it enters the engine.

High Horsepower Cummins

Aftermarket Exhaust Manifold (1045985SS) – CLICK TO VIEW


We will also have to upgrade your exhaust manifold to help the engine breath easy, forcing all that extra air into the engine, you have to make sure that air can get back out, an aftermarket exhaust manifold will flow 50% more air than the stock manifold.

In order to get the engine to hold all of this extra boost you are going to need some bad ass head studs. I use only ARP head studs on all of our builds. They are the best in the business and they will hold the power.

Click Here To View ARP Head Studs

These parts will get you the power but in order to keep that power reliable you are going to need an aftermarket cam and a set of valve springs. These parts will allow us to spin higher RPM’s at higher boost levels while reducing drive pressure and EGT’s.

Click Here To View 110lb Valve Springs

Click Here To View Aftermarket Cam Shaft

At this point the engine is good to go, but you need tuning. The best tuner on the market for your truck is going to be the Smarty SSR. It allows us to custom tune the bigger injectors and turbos.

Click Here to View Smarty SSR

All of this power is worthless if you can’t put it to the ground. You are going to need one hell of a tough transmission. This is the same transmission I am running in both of my Dodges.

Click Here To View ATS Stage 6 Transmission

That pretty much covers the performance parts needed to build a reliable 750+ horse power that you can still tow with. I may have missed a few little things but these parts will help you start planning your budget for the build.

There is going to be a lot of labor to install all of these parts. I would plan on spending around $5,000 to have everything installed. Unless you plan on tackling the knuckle busting yourself. If you have more questions, give us a call 770-267-0773 Lead Foot Diesel Performance.

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