Lil Red

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Duramax Diesel Power Project


Rocket science is a whole lot more entertaining when you actually get to drive one! The primary mission for this Duramax Diesel Power Project includes exploring the performance potential of the Duramax/Allison in a lightweight 4x4. This truck was first driven in April 2004 soon after completing the conversion.



A wide range of Duramax performance products have been tested, and more are in the works, which help us explore the performance potential of the Duramax/Allison powertrain - both on the dyno and at the track. In addition to performance products that increase fueling and boost pressure, a nitrous oxide system was included in the range of tested products. Many of these product reviews are currently available online here at The Diesel Page which help to explain what we did and why we did it.




A 4" exhaust system, 4" polished stainless exhaust tip and Bilstein HD shocks were installed in May 2004 after the body work and paint had been completed. A custom exhaust system was chosen because we needed a 4" tailpipe without pre-welded hangers to work for this rather unique application. There is no muffler or catalytic converter installed, which means the truck sounds a little more like a hot-rod. The addition of a set of CalTracs traction bars help control axle-wrap during a launch.

After exceeding the power/torque limits of the factory Allison automatic, we installed an ATS Allison transmission in 2005. There are several different ATS Allison options available from mild to wild, and ATS set us up with what this particular truck needed. The new transmission shifts mildly when dialed back for daily type driving, but performs with authority when needed.

Prior to May 2004, we had been looking for just the right set of tires & wheels before we finally settling on the silver finished factory Chevy SS 20" x 9" aluminum wheels. The matching Goodyear Eagle tires in 275/55R20 were an excellent choice, being almost 32" in diameter and more than 11" wide.



The original 10-bolt ½-ton rear axle was replaced in late 2004 with a disc brake equipped six-lug 9-1/2" 14-bolt semi-floating rear axle. Our replacement axle was rebuilt with a new Eaton Positraction differential, new 3.42 ring & pinion and all new bearings and seals. Other than shortening the rear driveline about 3/4" and upgrading the rear driveshaft u-joint to a 1350, this was a bolt-in upgrade that has performed well in this lightweight truck.



This project was about power and performance, but it also provides a tremendous opportunity to learn more about the powertrain in the process. The payoff is all of the new articles and product reviews that result from the buildup and testing. Aside from providing more interesting content for the web site, members learn more about product application for their own trucks, and manufacturers/vendors gain exposure by sharing their knowledge and expertise. Everyone wins!

The above is about midway through a 12.9 second run, showing Lil Red squatting the rear and lifting the front all the way through the 1/4-mile. This photo was shot during one of the bracket runs, where they handicap the faster trucks - allowing the slower trucks to leave first off the line by some whole or fraction of a second. In this case, the Dodge got the green light about a half second before Lil Red. The Dodge was overtaken well before reaching the lights.

This truck has appeared in the January 2007 issue of Diesel World magazine, the May 2006 issue of Diesel Power magazine and in three separate issues of Truck Trend magazine.

TDP

The Duramax Conversion Guide is now available! This new second edition includes glossy full-color photo-quality front and back covers, a completely updated and revised interior that includes 62 glossy pages (17 B/W + 45 full color pages) filled with updated photography and graphics, along with even more information that will not only help you succeed, but will inspire you to complete your project.This professionally written and bound volume illustrates what you'll need to know when installing a Duramax 6600 diesel engine and Allison 1000 automatic transmission into a 1988-98 classic (OBS) C/K GM pickup truck or Suburban (plus boats and even the 1980s trucks).

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Was in town on Tuesday to take a few photos of the brand new 2021 Duramax Diesel pickups. The Chevy dealership had just received their very first 2021 model year trucks... due to covid-19 delays this year, so I made arrangements with the manager a couple of weeks ago to drop in for a few photos when they arrived. They are sweet. I'll have a new article available soon.

It was a really-really nice day here (especially for November 3), so I thought I'd drive Lil Red to the dealership.



Jim

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9-1-2021 - Felt confident about the recent Duramax head gasket R&R in Lil Red so we took about a 300 mile overnight road trip on Mon/Tue. No oil use, no coolant loss and no abnormal pressure buildup in the cooling system.



This photo was taken on I-90 about 60 miles east of Missoula Montana, headed west/home. The speed limit on I-90 here is 80-mph. The 3.42 gearing and 275/55R20 tires make for fairly tall gearing. The truck loves it. Once off the Interstate, we crossed the continental divide on US-12 coming/going. Truck stays in OD with ~8-10 psi boost and ~1000 degrees EGT at 60-70 mph while climbing the grade (corners determine speed). So far so good!

Edit: The Kennedy 600+hp ECM race programming (video- did 632 on its last dyno pull) was replaced recently with a new Kennedy program that includes both a stock power/fuel economy setting plus a +100 horsepower switchable setting. This was a part of a civility plan for this truck. The ~stock program also allows the performance Allison to shift with near stock manners. Overall, it's a lot more pleasant to drive, yet it retains the muscle (when selected) that can surprise folks. Also, John corrected the speedometer for the 3.42 differential gearing and tire size as part of his programming for me - thanks John.

This engine is also running a Banks "BigHead" wastegate actuator, which has a larger diaphragm than the stock actuator, and it includes an adjustable control rod - to control spring pre-load (thus boost pressure). Current rod adjustment produces a max of 25-psi boost pressure during a brief full pedal run - still goes like a bat even with stock power. Boost pressure quickly rises to its 25-psi max and stays there as long as your foot is in it. The truck delivered 22.13-mpg on the last fill-up (250.1 miles), which was a good part of this trip. Great fuel economy, considering the speed... I'd like to do a serious fuel economy run some day to discover what this 3.42 geared 5,000-lb truck is actually capable of when driven slower... I just need more willpower...

Read more about Lil Red's Duramax Head Gasket Replacement HERE. If you're not already registered here at The Diesel Page Forums, please do. It's free. Register Now! You'll need to register to open the head gasket replacement link.

Jim

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I've embarked on a civility program for Lil Red. The first step was to add a foam rubber block (5 x 5 x 24") to the back of the cowl injection hood scoop - on the inside. I theorized that a lot of engine noise was coming through the screened back of the scoop and into the cabin air inlet in the factory windshield cowl. The block was painted black on the visible side (visible through the windshield), so it looks like a foam air filter. That block of foam cut the noise a noticeable amount.

Next, I added a couple smaller foam blocks (each 5 x 5 x 5") that were squeezed into the area between the scoop and the underneath hood framework - center and near the hood latch, to dampen resonant noise. That helped too. The hood now sounds like a normal hood when shut. I plan to add a full-size under-hood pad in the near future, to complete the hood sound abatement portion.

On the "to-do" list is a muffler. Right now, the truck is running straight piped. I'm looking for a muffler that produces a mild throaty rumble without any droning. Since I'll be driving this truck more as a fun daily driver, I want the exhaust note to be a little more civilized, yet still sound as good as it looks.

Beyond that, I'll be installing a rubber bed mat, to help with the echo chamber. It already has a fiberglass bed cover, but not much else in the way of sound deadening...

Let me know if you have any other ideas...

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I've been asked a few times these past few months about the newer style dash I installed in Lil Red (1989 Chevy K1500).



They asked whether the newer dash was too wide for the OBS (Old Body Style) truck's cab interior, they asked about the HVAC (heating-venting-air conditioning) package used in my truck, and they asked about the electrical harnesses I used.

The newer dash is wider than the original, but it fits if the door panels are modified to be as thin as possible. The above photo shows the modified 1989 door panel. Basically, the door panel is only about 1/8" thick where it fits against the new dash. I cut that section out of the original door panel and plastic welded in a piece of 1/8" ABS flat sheet to replace it. Then, the new ABS piece, once shaped to fit exactly, was covered in vinyl imitation leather, before I used an automotive interior spray color dye to get the door panels to color-match the new dash.

The HVAC package beneath the dash and dash-mounted controller I'm using are the original 1989 units. However, if doing all this again, I'd be tempted to install a new HVAC package that matched the new dash. This way, the ducting could be easier to complete and the dash HVAC controller would be plug-n-play with both the HVAC package and the new wiring harness borrowed from the Duramax/Allison donor truck.

Speaking of electrical harnesses... I recommend using the GM factory Duramax donor truck's electrical system harnesses. With the exception of Lil Red's lighting system (head/tail/courtesy, etc) the remainder of the truck's wiring was swapped out for the new. This actually made the conversion easier and simpler - though you have to be committed once the original wiring system has been stripped out... Incorporating the complete OE Duramax donor's wiring harnesses and various control modules allow you to incorporate any of the luxury and safety features into your build that are found in the newer trucks. These optional features don't have to be used/incorporated, but they are possible when using factory parts. You can pick and choose. For example, the airbag system could be transferred to your earlier truck. The 4-wheel ABS system could be transferred. Then there's the security system, audio system, climate control, even OnStar and any other feature that was found in your Duramax donor truck. In talking to (or through email) hundreds of conversion project owners, these factory offered features have been incorporated in part or in whole in some number of the trucks that have been converted through the years.



There's no going back... This is a very early photo showing how Lil Red's interior looked after the original dash and most of the wiring had been removed. Was a little scary at this point.

So, it took time to make the decision... The indecision about whether to strip out the original wiring (and swap the dash) cost me nearly a year, because at that point in time (late 2002 - late 2003) no one outside of GM had converted an earlier GM truck to D/A power. Seemed like a big-big risk at the time. Now I know it's not... Once the decision had been made, the conversion you see here was completed and drive-able in just a few months (first driven in late April 2004) - which included the dash conversion, all of the new bodywork/paint, all new interior from carpet to headliner, intercooler fabrication/completion, a working air conditioning, custom 9-1/2" 14-bolt rear axle with an Eaton posi differential, rear disc brake conversion, new custom front/rear driveshafts, and a host of other mechanical and cosmetic additions that may not be necessary for your project.

All that said, I ask that those planning a conversion consider retaining their own project truck's original dash and HVAC package, and just modify the truck's original instrument gauge panel surround to accept the newer instrument panel gauge cluster from the Duramax donor - and install the modified Duramax donor's steering column. This simplifies the total conversion. I found that installing the new dash doubled the time it took to complete the conversion in my truck. You have to be committed and you need to accurately assess your skill level if you decide to swap the dash.



However, in all of the car shows and diesel events I've attended with this truck, I will say that I'm surprised that the newer style dash usually draws more attention/comments than does the clean OE appearance of the Duramax under the hood. Not sure what to make of that... A typical car audio shop should be able to help you create a new gauge panel surround if you need help doing that part - this is what they do for custom speaker installations, etc.

The dash install and most other items shown here are discussed in more detail in the Duramax Conversion Guide.

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Here's another interior photo - an early one - from a different angle.

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I just finished the installation of a 2" receiver hitch in Lil Red. This is a "Draw-Tite Max-E-Loader Trailer Hitch Receiver - Custom Fit - Class III - 2" Item #41524". Though it says "custom", it was a production hitch that I bought from Amazon in 2018... Just got it installed...

This receiver hitch is rated for a 1,000-lb tongue weight and a 10,000-lb gross trailer weight when using a weight-distributing hitch. Without a weight-distributing hitch, the rating drops to 600-lbs/6,000-lbs. More than enough for this 1500 series chassis.



Shown here is a device (a clamp pointed to in photo) I bought from Harbor Freight that was designed to reduce the rattle/slop for anything slid into the 2" receiver. There's always a bit of clearance designed into these 2" receiver hitches, so ball hitches or whatever ... slide in easily. A rattle-stop is necessary to keep the bumper-ette tight (shown in the next image).

I also needed to relocate the exhaust tailpipe hanger due to interference with the hitch mount. The above photo was taken just before the exhaust hanger was relocated.



Aside from the practical, i.e. towing trailers, a big reason for installing a receiver hitch was to provide some protection to the rear of the truck in case of a bump from the car behind at a stoplight or something similar. Shown here is a relatively inexpensive bumper-ette that would help. There are many other options available online that offer more strength and protection, but.. we'll see what develops. This one is pretty lightweight.



This was a more or less custom installation because I wanted the hitch to be tucked in as tight as possible - to make it less noticeable. In a typical stock installation where the rear bumper is retained, there would be room for the spare tire, but not here due to the roll pan requiring the hitch be mounted a bit farther forward. This required drilling new holes... though I don't think this hitch could be installed without drilling some or most of the holes anyway.

The engineers at Draw-Tite were especially helpful in answering questions about an off-the-shelf hitch fitting this unique situation. Though it was designed for an unmodified truck (1988-98 body style), this is a great hitch that fits the roll-pan very well.

The only negative... the hitch shown here arrived from Amazon with some chips in the finish (the hitch is heavy and the packaging could have been better). Amazon generally does an amazing job with shipping, so I'll cut them a little slack. I touched up the chipped areas using POR-15. It's all good. I'm happy with it. Now, I just need to get the trailer wiring/connector installed along with a brake controller.

This receiver hitch is available right now at: https://www.etrailer.com/p-41524.htm...+Series+Pickup with free shipping for $218. Amazon was out of stock when this was first posted.

Jim

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Here's an image of the Husky Liners floor mats installed in Lil Red. I bought these a few months ago, and just got them installed. I love them. I've had a set in my 2001 GMC for more than 20 years. They are the best mats I know of to help keep the carpet clean in our Montana winters - mud, snow and winter road de-icer are rough on carpet. I used to stress about either myself or passengers tracking in stuff, but these mats make it OK. The mats keep the water, mud and dirt corralled before it can run off onto the carpet.

My first experience with these mats was when John Kennedy drove to Ohio for our 2001 TDP Rendezvous. He had these in his truck. I wasn't sure what I thought about them at that time. But, after discovering that there wasn't anything on the market that would do a better job, I bought a set for my 2001 GMC - front and rear. Great choice! I still have them, and they still look/perform as good as new. That's why I wanted a set for Lil Red and for Sarah's Blazer.

The mats are form-fit for each truck make/model. The ones shown here were made for the 1988-98 GMT-400 body style GM trucks and SUVs. They are easy to remove from the vehicle, they clean up easily with just a light scrub using soap and water, and they stay put because of all of the pointy nubs anchoring into the carpet.

The front mats cost about $75 using Amazon Prime. Not many products I like, or would buy again, after 20 years... I do/did these!
https://www.amazon.com/s?k=Husky+Lin...ref=nb_sb_noss

[JohnC]

Too funny! I was checking their Amazon ad to see if I could figure out where they came from (Good news, made in USA). the TV was on, and when I looked up there was a WeatherTech ad on... (I bought a WeatherTech liner for the back of the GLS last fall after the dog barfed in the back...)

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Too funny! I was checking their Amazon ad to see if I could figure out where they came from (Good news, made in USA). the TV was on, and when I looked up there was a WeatherTech ad on... (I bought a WeatherTech liner for the back of the GLS last fall after the dog barfed in the back...)

I bought a set of WeatherTech mats for our 2016 Malibu. I still prefer the Husky Liners. The anxiety from winter muck and nice carpet is a thing with me... Living in MT doesn't help...

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I finally got around to installing the Husky Liners mud flaps for the front of Lil Red.



These are part number: 56221 listed as for the "1988-98 GM Truck/Suburban, Tahoe, Yukon - Mud Guard".

I like the look. Should help to keep the rocks off the rockers. They make a set for the rear too, but... The coming steps should help with keeping the rocks off the side of the truck too.


Jim