6.5 TD Swap into an A2 or M1123 HMMWV

[JimDu]

Hi All,
I’ve tried but failed to find the info I’m looking for, so please forgive me and point me in the right direction if this has been previously discussed. Has anyone swapped a HMMWV 6.5TD into an A2 truck? I’m not talking about adding a turbo to my engine. I’m talking about replacing the 6.5NA with a complete 6.5TD pullout, or a brand new complete engine. I know that generally any engine swap is a PIA. What I’m looking for specifically, is what needs to be done to the A2 truck to make it happen? It should be easier than swapping a 6.5TD into an A0 or A1 truck, in that I already have the 4L80E. I’m hoping it’s as simple as trimming the body to fit the turbo dog house, and getting the different exhaust components. Is that accurate? If not, what am I missing? Does an A2 require any body lift to accommodate the center-mount turbo? I want more power and torque, and I don’t want to lose ground clearance. I’ve looked at BMI’s turbo kit (ground clearance issues) and Bullet’s Eaton-based supercharger. AMG went with the center-mount turbo. I’d rather use OEM stuff and not re-invent the wheel. I’ll do the swap myself, with help from my family.
Many Thanks for your help!

 

[Mogman]

I have a thread on this, basically install the two trim pieces for the turbo dog house, the old exhaust will work as long as you have the correct down pipe and you should do at least a 1/2" body lift.

 

[Mogman]

Here is the link to my conversion, it is a little different as I had a 6L80 transmission but the info on the trim pieces starts on post 8 with part numbers.

M998 turbo conversion

I am starting to do a GEP turbo conversion on my 1992 M998 I call "Detroit" so maybe some would be interested in the "ride" Back story: When I was getting ready to install the 6L80 in Detroit I knew I was going to have issues with my doghouse, I was using a cable driven tach out of a another...

www.steelsoldiers.com

 

[JimDu]

Awesome.
Many Thanks for the quick reply and the info.
I’ll check out your thread.
Have a great day!

 

[JimDu]

Hey Mogman,
I have a couple of follow-up questions…
1. Did you make your own 1/2” body lift? Is one commercially available? I think there are 1” body lift kits available. I don’t want to go any more than that anyway, but what is the limit on lifts before one needs to worry about modifying wiring, steering column, tank straps, etc?
2. Is there a particular reason you went with a 6L80E instead of an Allison 6 speed, or just sticking with a 4L80/85E? Like driveline horsepower loss, packaging, availability, etc? I like the idea of an additional gear on each end for acceleration and to drop freeway cruising RPM, but how much does one really gain by making the swap? Sounds like a lot of money and effort, unless you had the three speed or no transmission at all…
No criticism! I’m just curious and trying to figure my best way forward…
Thanks again!

 

[Mogman]

I just bought 1/2" body pucks, I will look for the link later, then used some 1X1/2" aluminum bar to lift the hood hinges. that was all that needed to be done no steering or fuel tank needed.
I started with a M998 with a three speed and wanted to do something different and that was possibly the first 6L80 in a HMMWV, the Allison is much too much transmission for the anemic 6.5L Detroit, the 4L80E is fine as the 6.5L cannot make enough horsepower to hurt it.
Unfortunately you may find all the work installing a turbo engine is not worth the effort unless your original engine is toast, the 30 or so additional HP is no big game changer.
Most people will not admit this as they want to believe all that work was worth it.
While I did like the 6L it was an expensive endeavor that required some advanced skills to build the custom adapter so the stock transfer case would bolt up as nobody makes that adapter, add almost $1000 for the computer to make it stand alone.
The 6L however is a much more efficient transmission than the 4L with a much lower 1st and of course closer range shifts with 6 gears.

 

[JimDu]

Gotcha.
Yes please, the link would be appreciated whenever you can find it.
I guess I was hoping to find someone who could help me squeeze 250hp/500tq out of the stock 6.5TD by tweaking whatever can be tweaked. Turbo impeller, free-er flowing exhaust, dial up the fuel pump, etc. I think the swap would be worth it if those numbers could be achieved.
Is that possible?

 

[Mogman]

Gotcha.
Yes please, the link would be appreciated whenever you can find it.
I guess I was hoping to find someone who could help me squeeze 250hp/500tq out of the stock 6.5TD by tweaking whatever can be tweaked. Turbo impeller, free-er flowing exhaust, dial up the fuel pump, etc. I think the swap would be worth it if those numbers could be achieved.
Is that possible?

No, the P400 can make those numbers but it was a very expensive engine that had special crank, pistons extensive block and head work including a girdle to keep the lower end together, it also requires computer control, those numbers cannot be made with a mechanical injection pump.
The 6.5L barely stays together, even in stock form they have a high failure rate, if you managed to squeeze even 130HP out of it, it would not be for long especially in a Humvee where it is subjected to high loading and RPM

 

[JimDu]

Copy all.
Thanks!