Oh yeah - Bug list - The speedometer is off (a simple calibration issue). The idle lopes and the mixture is way too rich (you can almost watch the gas gauge going down and the exhaust really smells of gas). It's a bit too loud going down the freeway for my tastes so I might have the muffler changed out. The gearing is now way too low for this engine. RPM's about 2400 at 80 mph so I may have the final drive ratio changed so I can have a bit lower RPM on cruise. The first two are simple calibration issues and won't be much to fix. The second are going to cost me a bit more $$$ (and might have to wait for a bit) but I really want this to be right for our purpose (daily driver)...

 

Thanks for the prod; This is the conversion that I was planning even before I found my 2010 I5. Looked at Jeeps had a Dodge Hemi at the time. Turned me toward Hummers. Alpha average about $10000 more than I5 and didn't want another underrated 5.3. Bought an immaculate, 2010 never off the highway, just with this conv. in mind.
My plan is a low miles L92 out of a escalade 6.2, stock 403hp, would like a 6L80 trans. but maybe more practical labor and $ wise to beef stock. But the gearing HAS to change to make this a feasible swap. Currently 4.55s to get a 5 cyl even move this beast.

I'm thinking 3.71s or some where in that range, suggestions???????

 

That is my dream swap in my H3T, definitely go with the 6L80 if you can. 6L80 1st gear is steep so I'd run lower gears, upper 3's at the most. Here's a thread with more 6L80 swap info:

6L80e 6spd Conversion - Page 18

 

We are still tweaking the computer and trying to make everything a bit more compatible with everyday driving (this is a learning curve). We will be changing out the final drive ratio in the future since this thing is revving way too high at highway speeds.

Here's the issue I had with Mash Motors in this conversion and why I don't recommend anyone do business with this guy. Yes, he has done successful conversions but his business model is absolutely the pits. My shop wanted to take my existing harness out of the truck and send it to the computer people to rewire it so it would be compatible with the LS3 but it would take an additional 3 weeks to have them finish it. They would send the harness and computers back as a package with a "base" program already downloaded so that only additional tweaks would be needed. This would have cost me about $800. I was impatient so I contacted Mash to see if they can expedite me a harness so that I would not have to wait the 3 weeks. He said he could do it but the price was a whopping $1900!! I really wanted to rush this job along so I bit the bullet and ordered it (huge mistake on my part). First, he was 2 weeks in getting me the part so that meant I only "saved" one week. Then he did not provide enough information on the mods required to connect this supposedly "complete" harness to a couple of connectors in the engine bay. After many attempts to contact him for help (never returned calls or emails) I finally called the credit card that I purchased this with and opened a "dispute" because the harness was not usable as shipped (we are now something like 4 weeks into the project so I've actually lost a week of "progress"). This finally gets his attention and now he starts feeding us bits and pieces of info as the dispute will only remain active for about 3 weeks. We finally get enough info to get it running but some things are not yet correct and we have to find a connector for the body module that he said he could get for us. My shop finally found one in a wrecking yard and used it. We are now something like 7 weeks into my 4 week project. As the time is about up for me to "escalate" my dispute and since we now have the harness functioning (which seems to have been his plan all along) I drop my dispute and consider this an expensive lesson to me to listen to my local guy and don't trust someone who is hundreds of miles away. If I'd done it my guys way the project would have been done in 4 weeks instead of 10 (not to mention the $$ I would have saved).

Want to do business with Mash, go ahead. I've told you my experience with him. I'm sure if you just drop your H3 there and let him do the entire project he will get it done but don't expect any kind of support afterwards...

 

Hi !
Thank you for sharing this info. ! I have approx. 149,000 miles on my '06 and when the I5 finally lays down, I am definitely going to do an LS swap. I really like my H3, and don't foresee getting rid of it. Now about the transfer case & front/rear differentials, what are you considering ? Maybe a ford 8.8 setup ?

Steve.

 

Absolutely luvin this thread. Gr8 info and enjoyable to read about. I know what ya mean about the impatience and quick fixes...

 

Finally some video. Here's a walk around.


And here's a test run 0-60 which came in at 7.1 in spite of some stumbling off the line. We are going to spend some more time tuning to try to fix that.

 

Here's what I've learned about this conversion and what I can pass along as advice to anyone trying to make their own. First, unless you are making a drag racer don't do like I did and go for the biggest baddest engine you can buy. As it turns out the engine I bought has more HP than I need and because of the aggressive cam it will not perform well at low RPM. I am planning to spend some more $$ to put a stock cam in it to fix this. Was a waste to spend extra $$ for HP and then have to pay a second time to tone it down some. I think a 6.0 standard cam engine would have been a better choice.

I would also go with a quieter muffler unless you just like loud. I kept the factory tranny but it was completely purpose rebuilt to handle the additional HP. The final drive gears are much too low for this engine and it turns almost 3000 RPM at 80 MPH so that is another expense coming maybe next month.

Once these changes are complete I'm certain this will be exactly what I wanted. An H3 that actually runs and drives like a powerhouse (and from what I've seen so far the gas mileage will actually be a bit better).

 

Nice! Changing the rear gears out should not be too awful expensive.

 

I got tired of taking this back to have their "tuner" look at it so I broke down and purchased a HP Tuner Pro and have started to play around with the tuning myself. If anyone else here has this tool and is experienced in using it I would appreciate any "education" I can get. I did buy a tuner book and I'm reading that.

What I did first of all is back up the tune information so that I can always go back to the start. They used the H3 Alpha as the base tune and worked from there. What I did was take their tune and then copy over some settings from the sample 2014 Corvette tune included with the HP Tuner. First I just tried copying everything from the Corvette tune and the car would not even start. Then I copied only the fuel portion of the tune and it ran pretty good. They I tried copying the spark advance from the Corvette and it still ran good. I then tried to copy the MAF portion and it would not start. So I know that my setup differs from the 2014 Corvette in the MAF setup. Right now it's actually running pretty good but I still have some stumbling at small throttle inputs. It is a bit better than before though so I'm doing some more reading and will make some small changes when I know more.

I did find that there's a setting for the gas sender so I have played with that a bit but I really need to find another H3 so I can copy those numbers and input them into my tune.