Conversion from 6.2 to Duramax in a Defender 90

I am the one that have been working fiendishly to install a turbo onto a 6.2 motor that is installed in a Land Rover Defender 90, with the help of the forum I have been able to try a few different things. For example, my mechanic is trying to locate an old school bus to rob some parts out of it. Even if we are successful, the job to completion is still going to be a challenge. Because of this herculean effort, I am thinking that to get more power it may make more sense to convert to a Diesel that have a turbo already installed and can fit in the engine compartment of a Defender. This the major problem that we are having is that there isn't any room for an after market turbo.

I was talking to my neighbor and he was telling me that the Duramax has less volume that the 6.2 with more power and good gas mileage. I don't need a lot more power but, enough to turn my Defender gears comfortably.

Are there any issues that I need to be aware of? What generation of Duramax would be best for this application? Lastly, if the Duramax is not the engine to convert to then please offer a better alternative is it exists. Thanks for your time you guys are awesome!

Madrugador (Defender 90, 1995)

I still say that considering that they put non-turbo 6.2s in Suburbans with a curb weight headed towards 5000lbs and 3500s with a curb weight over 5000lbs and a GVWR of 8600lbs or more, it just doesn’t seem right that a 6.2 is going to need substantially more power to push a Defender under 4000lbs...

Hi Trbankii,

You may be right! The engine has not been professionally tuned at a Diesel shop. It is at such a shop now and along with installing a turbo they are tuning it also.
They told me that it was needed. A turbo installed would increase the efficiency of the vehicle and just yesterday my mechanic told me he has a way to get a turbo into the vehicle. Is it true that the Duramax diesel is more fuel efficient than the 6.2 because it is electronic? (That can bring along a few more headaches of its own)

-Madrugador

Efficiency is relative to application. The Duramax is efficient, when used as intended and designed. The same is for the 6.2L, 6.5L, and commercial OTR engines. The Detroit 60 is a very efficient engine, when used to move 80K over long distance. The 6.2L engine is very efficient in a rig moving 10K. On a more narrow scale, the same principal applies to a turbo. A turbo can increase efficiency when more power is needed to move a greater load, but it's a liability with lighter loads. Unless you need/want more speed than a 6.5L N/A can offer, a vehicle that may never exceed 4K will gain no efficiency with a more powerful engine, or a turbo.

Add to that, efficiency is a package deal. Initial cost, fuel economy, maintenance and repair all have to be considered. You can trade any/all of the above for speed. Balance what you need with what you want. There's a reason why we never discuss the fuel economy of Rolls Royce, Bentley, Lamborghini or Ferrari. It would be entertaining to do so, but has no real purpose.

Quote:

---

Originally Posted by Madrugador

I am the one that have been working fiendishly to install a turbo onto a 6.2 motor that is installed in a Land Rover Defender 90, with the help of the forum I have been able to try a few different things. For example, my mechanic is trying to locate an old school bus to rob some parts out of it. Even if we are successful, the job to completion is still going to be a challenge. Because of this herculean effort, I am thinking that to get more power it may make more sense to convert to a Diesel that have a turbo already installed and can fit in the engine compartment of a Defender. This the major problem that we are having is that there isn't any room for an after market turbo.

I was talking to my neighbor and he was telling me that the Duramax has less volume that the 6.2 with more power and good gas mileage. I don't need a lot more power but, enough to turn my Defender gears comfortably.

Are there any issues that I need to be aware of? What generation of Duramax would be best for this application? Lastly, if the Duramax is not the engine to convert to then please offer a better alternative is it exists. Thanks for your time you guys are awesome!

Madrugador (Defender 90, 1995)

---

Adequately defining the intended use and how big the budget is will dictate choices, from a logical position. We're not always logical though.

Quote:

---

Originally Posted by More Power

Adequately defining the intended use and how big the budget is will dictate choices, from a logical position.

---

This. A lot of advise has been offered in your other posts on the subject. It just seems that something doesn’t add up. Perhaps your use or expectations are different from what most people are expecting?

Hi Guys,

First of all, thanks for all of the input over the course of the year. You have and are making me think about a lot of things.

Second I have made a lot of mistakes through out this project, trying different packages of one kind or another. For example, different transfer cases, a couple of different overdrives, the Banks turbo kit for the 6.2, etc. This has been a work in progress for about 10years. I bought the vehicle in 2005 and love everything about the vehicle except the engine. The vehicle only had around 18K miles on it when I bought it from the 1st owner, he was a doctor and just didn't driver it. I was told that a short time before I bought it a new engine was installed into the vehicle because it sat idle for over a year and when it was finally started some part of the engine blew up and was "toast". When I received the vehicle the new motor had only between 1K to 2K on it. The question of, Why did I got rid of a "perfectly" good engine begs? Well, I knew that the Land Rover engine could not be trusted and that at some point in the near future, it will be a major source of headaches. I just want to cut my "losses" now, so a few months after, I embarked on the adventure of the conversion.

Like a lot of things in life you start out innocently with the notion that it would be an easy project with the right parts and know how. My mechanic and I thought that a couple of months would suffice for this project, but then bad luck "kicked in". There was a company in England that manufactured kits for the conversion LR to 6.2 or 6.5. My mechanic thought the 6.5 would be perfect for the vehicle, but I thought that instead of the 6.5, the 6.2 should be perfect for this vehicle because of its size. (Maybe a mistake!) I bought the engine and after it arrived, I order the kit from England. A month goes by, no kit, the owner tells me it is coming, 2 to 3 weeks later I call to a disconnected phone no. I investigated more and discovered the company when out of business. Now we were stuck with a motor with no conversion kits. My mechanic decided to take on the project of making the straps and brackets himself but it was a monster of a job for him in the interim a tornado hits the shop and destoyed about half of it and a "boat load" of cars. Somebody was smiling on my vehicle that day because there were two cars on each side of mines that were completely destoyed. It just happened that mine car was on the hoist in the air and for some reason didn't receive a scratch.
Incredible!!! Long story short... the vehicle was in the shop for 3years! yes 3years! with all of the trials with the gears and such, the saga is continuing. After the turbo, I want a snorkel. A snorkel should do wonders for a diesel.

Why go through all of this? Because I like how the vehicle rides and handles with great looks, also I love my 6.2. What I want in a vehicle that is for it to be fairly fuel efficient and can cruise effortnessly at 75 in all terrains and weather conditions.

Hopefully, this will give you a little more "color" into my situation.
-Madrugador

Quote:

---

Originally Posted by Madrugador

My mechanic thought the 6.5 would be perfect for the vehicle, but I thought that instead of the 6.5, the 6.2 should be perfect for this vehicle because of its size. (Maybe a mistake!)

---

The 6.2 and 6.5 blocks are the same outside dimensions. The only real difference is the added space for the turbo on the 6.5 and possibly the configuration of the other accessories - alternator, power steering, etc.

Quote:

---

Originally Posted by Madrugador

After the turbo, I want a snorkel. A snorkel should do wonders for a diesel.

---

What sort of wonders? A snorkel only moves the air intake higher to avoid sucking water into the engine during deeper water crossings. It doesn’t improve performance.

Quote:

---

Originally Posted by Madrugador

What I want in a vehicle that is for it to be fairly fuel efficient and can cruise effortnessly at 75 in all terrains and weather conditions.

---

That should be mostly attainable with the 6.2 given the proper gearing - which has been a question all along in answers to your posts.