FAQ

Frequently Asked Questions (FAQ)

What lift pump size do I need for my 2001-2016 Duramax based on horsepower?

For 2001-2016 Duramax trucks, lift pump sizing depends on your horsepower goal.

Up to 600 HP
100GPH system

Up to 1,000 HP
165GPH system

Up to 1,500 HP
290GPH system (competition use only, intended for 1000+ HP builds)

If you’re unsure which one to choose, contact us and we’ll match you with the correct setup based on your build.

Injector sizing and power recommendations

Approximate horsepower capability. Proper tuning and supporting mods required.

Sportsman / Stock Injectors: Up to 600 HP
30% Over: Up to 650 HP
45% Over: Up to 700 HP
60% Over: Up to 750 HP
100% Over: Up to 850 HP
150% Over: Up to 900 HP
200% Over: Up to 1,000 HP
250% Over: Up to 1,300 HP
300% Over: Up to 1,500 HP
400% Over: 1,600 to 2,000 HP
500% Over: 2,000+ HP

What CP3 pump do I need for my injector size?

Proper tuning and supporting fuel system upgrades required.

Sportsman / Stock Injectors (up to 600 HP)
Stock CP3 or Sportsman CP3

30% to 45% Over Injectors (up to 700 HP)
10mm CP3

60% Over Injectors (up to 750 HP)
10mm or 12mm CP3

100% Over Injectors (up to 850 HP)
12mm CP3

150% Over Injectors (up to 900 HP)
12mm or 14mm CP3

200% Over Injectors (up to 1,000 HP)
12mm or 14mm CP3

250% Over Injectors (up to 1,300 HP)
14mm, Alpha 550 CP3 or Dual CP3 setup

300% Over Injectors (up to 1,500 HP)
14mm, Alpha 550 CP3 or Dual CP3 setup

400% Over Injectors (1,600 to 2,000 HP)
Dual CP3 or Alpha 550 CP3 system

500% Over Injectors (2,000+ HP)
Dual CP3 or Alpha 550 CP3 system

What’s the best Duramax platform to build a race truck?

LB7 or LLY, hands down.

Better ECM tuning capabilities make it way easier to make power, and the AL5 controlled Allison makes it way easier to actually put the power down. Plus, the chassis is light.

I’m looking for an item but I don’t see it on your website. What should I do?

Call, text, or email us. Chances are we have it available or can get it.

There are a lot of products we still haven’t added to the website yet.

Phone: 443 370 3370
Email: DelaneysDieselPerf@gmail.com

How do you guys get engines to live long at high horsepower?

Great question. It comes down to the truck’s setup and the tuning.

For high horsepower and competition builds, the recipe is:
Big single turbochargers
Large injectors
A proper fuel system
And proven tuning

Anyone can make power. The right setup is what keeps it alive.

I just bought my first Duramax. What should my first modifications be?

If you have a 2001-2016 Duramax, the first mod should be a lift pump.

The factory injection pump pulls fuel under vacuum. Supplying positive, filtered fuel pressure is a huge advantage for reliability and injector life.

For LML trucks, we strongly recommend doing a CP3 conversion as early as possible. Spending a couple thousand now can save you 10,000+ if your CP4 fails.

Are L5P trucks reliable?

Yes. L5Ps are the longest tenured Duramax for a reason. Great power and reliability.

As mileage climbs, we commonly see:
Injector pigtails failing
Driver rail and pigtail failure
Passenger rail sensor and pigtail failure

We stock these and recommend keeping spares in the truck.

I want to upgrade the turbo on my stock Duramax. What size do you recommend?

Honestly, we always recommend building the transmission first.

Your stock turbo can make enough power to wipe out a factory transmission. No sense upgrading airflow if the transmission can’t safely hold it.

Transmission first, then turbo.

How important are torque converters?

A torque converter and transmission are the foundation of your build.

You can have the best engine, turbo, fuel system, and tuner, but without a properly spec’d converter or built transmission, the truck will underperform and you’ll be fighting it the entire time.

If I get tuning through you guys, how long do revisions take?

We take this seriously because we know what it’s like to be left hanging.

Revisions are typically handled within 2-3 business days max.

We need data logs before any changes unless you’re changing setups. If we find issues in the logs, we’ll let you know what we see and help pinpoint the problem so your truck runs right.

Do you offer install in house?

Yes. We are a full service diesel shop and can install everything we sell.

Do you ship?

Yes. We ship all items available on our website.

How long does shipping take?

Most in stock items ship within 1-2 business days. Orders placed by 2:00 PM Eastern may ship the same day depending on workload.

Do you accept returns or exchanges?

Yes. Returns are accepted as long as the item is unused, uninstalled, and in original unopened packaging.

No returns on:
Special order parts
Installed items
Opened items

Can you help me choose parts based on my build?

Absolutely. That’s the whole point of what we do.

If you’re not sure what parts you need for your goals, reach out and we’ll help you pick the right setup the first time, with real advice based on what works.

I live far away and can’t bring my truck to you. Can I still call or email for help with my setup?

Yes. We work with customers all over the country and we’re happy to help you plan the right combo for your truck.

Because of the high message and call volume, we require a $100 consultation fee for detailed build planning and tech support.

If you end up purchasing parts from us, that $100 is credited toward your final invoice.

This protects both of us and ensures you get real help and the proper time and attention your build deserves.

Do I need supporting mods before ordering injectors, turbo, or fuel system parts?

Yes. Supporting mods matter. Fuel system, transmission, airflow, and proper monitoring are the foundation. If you’re unsure what you need, contact us and we’ll help you choose a setup that works together.

What if I order the wrong part?

If you’re unsure what you need, please contact us before ordering. We’re happy to help you choose the correct parts the first time.

Do I need a lift pump on a mostly stock truck?

For 2001-2016 Duramax trucks, yes. A lift pump helps supply clean, positive fuel pressure to the injection pump and improves reliability long term.

What monitoring should I have before adding power?

We recommend monitoring at minimum:
Boost
EGT
Transmission temperature
Fuel pressure

Monitoring is cheap insurance and prevents expensive failures.

Do you ship to California?

Unfortunately, California’s regulations make it nearly impossible for us to ship most performance parts there.

Where can I follow your builds and shop content?

Follow our shop builds, customer builds, and real world results here:

YouTube: dmax_dante
Facebook and Instagram: Delaney’s Diesel

Important Notice

Delaney’s Diesel provides some aftermarket performance parts intended for off road and competition use only.

We do not condone the use of aftermarket performance parts on street driven vehicles where prohibited.

Buyer assumes all responsibility for the use, installation, and operation of any products purchased. Delaney’s Diesel is not responsible for misuse, improper installation, or any damage resulting from the use of these products.