H3 Performance questions...

[Babyjohn460]

Hello all! Ok so, after all the recent repairs (trans, torque converter, trans cooler/radiator, heated seat switches, ball joints and alignment) I decided to pick up a Superchips tuner last week for the Alpha. This past weekend was a fairly good test, 8 hour round trip camping trip with loaded toy hauler on the back. The tuner made a noticeable power and transmission difference. Not sure if it's a $350 difference, but a difference none the less. Was able to stay steady at 65-70 mph no problem. Figuring out the unloaded fuel mileages this and next week to see if it goes up or down with the tuner on different settings. Since the tuner was added, I had a few things I was hoping someone else has some info on.
-One thing I didn't like that was a selling point for the tuner was it was advertised as being able to change your axle ratio/tire size in the computer to adjust your speedo. Unfortunately, it seems GM doesn't allow this adjustment without a complete PCM retune, is this correct?
-Already have a high flow factory replacement air filter ordered to help get some more air into the intake. Has anyone played with the intake to get more horsepower? If so, what did you do and was it worth it? Seems like the intake system on the 5.3L is pretty no nonsense as it is. I've seen some people with AirDoc "systems" but not sure if they're worth the $$ since the factory air box is already, for lack of better term, a cold air intake. Are there any factory intake hacks to get more air flow?
-And lastly, I've been kicking around the idea of chopping off the "S" piping from before the muffler back and bending up a straight pipe from above the rear axle and exiting the passenger side of bumper. Has anyone done this on an Alpha? Notice any performance difference or is it all noise? How much louder was it? Alittle reluctant to do this as I'm not sure if I want the exhaust noise bouncing off the camping as I drive if it's a lot louder.

 

[GreatDaneHummer]

I felt the AirDoc is worth it to get a smooth direct flow of air into my throttle body. I do have the I5 and no it didn't give me some super imaginary power boost but at least it is clean looking and a little more power at top end. I combined this with the PCM tune from NC and it seems to add realistically maybe 10hp total. If I had a v8 I would look into combining these upgrades with a ported throttle body and maybe a good set of headers on the engine. Do a cam and new heads you can get a lot more power to wake it up.

Great article below on some 5.3 build up options for ya.

http://www.trucktrend.com/how-to/engine/1208tr-5-3l-bow-tie-builds-mild-to-wild/

 

[650Hawk]

I made my own "Air Doc", by cutting off the stupid resonator (or whatever it's called) and covering the hole with a piece of ABS plastic, siliconed and pop riveted in place. Can't say I notice a difference on my Alpha, but the stupid resonator just bugged me.

 

[BIGFRY77]

as far as headers go you would have to have custom ones made as I am not aware of any you can buy that will fit in the engine bay.

 

[Babyjohn460]

Yeah I don't think I'll end up going the headers route. If anything, for reliability sake. Road conditions in the winters by me take its toll on parts like that. Thanks for that link, GDH! Some good info in there. I think I may end up going with an AirDoc. If you found a marginal improvement with it on your i5, it should work nicely moving a little more air with the V8 and that programmer.
As far as I've found, that "resonator" is just for noise, likely slowing the air at the same time. I've heard that flap in between the fender and air box is the biggest restriction though.


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[GreatDaneHummer]

For my I5 exhaust I did an MBRP resonator and Flowmaster 44 muffler. Seems to work pretty well without being too loud on a long trip. Just an idea.

 

[justin94tt]

You should be able to change the tire size within he tuner so the speedo is calibrated correctly.

 

[Babyjohn460]

You should be able to change the tire size within he tuner so the speedo is calibrated correctly.

That's what I thought but it's not in there. Have searched extensively. Still have to get Superchips on the phone though. I hope I still can so my speedos back to right. At least before the regear and 35's.


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[2010H3TAlpha]

I love fast trucks but these trucks are slow and require serious investment to be even on par with most 5.7L+ full size trucks. Mine with tune, Airdoc intake, and cat-back exhaust EMPTY still gets absolutely spanked by my buddy's bone stock 2013 RAM 1500. I really wish there had been a super Alpha with a 6L or 6.2L and 6L80 trans but then it probably would have been a $50k+ truck, crazy money for a midsize. But it would have been pretty cool!

Some lady in a brand new SRT8 Jeep tried to race me on the highway today but I just laughed. Our trucks are cool but ~300wtq on 35's isn't winning races anytime soon. I'd love to do a cam but then I'd want to do heads, valvetrain, etc. Then if I am doing all that, might as well do the bigger motor. Suddenly $20k later the gain might be 1 second faster 0-60; worth it to some but not to most. IMHO 4th gear already puts rpm too high for 70mph cruise so a regear isn't on my to-do list. These trucks really needed a 6-speed, not the very limited 4.

The thing I liked most about the tune was getting rid of the dangerous throttle lag GM uses to protect the drivetrain. Nothing like turning left on a blinking yellow with a limited gap and the truck hesitates with the pedal to the floor and suddenly it becomes a sitting duck. E-throttle be damned! And of course to fix it back in 2013, the only option for the 2010 Flex Fuel motor was a $700 HPTuners setup, no handheld programmer was available at the time. Madness! But at least we plan to buy a GM SUV soon so I can tune that as well with some of my remaining credits.

 

[amrg]

Do a 6 speed swap (been done already) and your golden. Wil be like driving your alpha on 32s all again (with 35s). More low end torque and slightly lower rpms in 2nd overdrive!

 

[4Lo-Tank]

That's what I thought but it's not in there. Have searched extensively. Still have to get Superchips on the phone though. I hope I still can so my speedos back to right. At least before the regear and 35's.


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Then you have the lower end tuner. I have a superchips for my 09T alpha and it allows for adjustment. Did you look under the advanced settings

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[BIGFRY77]

These trucks were not made to be street demons... It would be the same thing if you challenged them to an offroad race, it simply would not be fair the hummer would win because the other trucks were not designed to have the same level of off road capability.

Comparing strawberry's to grapefruit and why they don't taste like kiwis here....

 

[Babyjohn460]

Who's expecting a Hummer to be a race truck??


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[Babyjohn460]

Then you have the lower end tuner. I have a superchips for my 09T alpha and it allows for adjustment. Did you look under the advanced settings

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What model do you have? I called summit before ordering for that exact reason and they said the 48xx did the speedo recal and engine fan setting and the 28xx did not.


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[rsc]

Who's expecting a Hummer to be a race truck??


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Rod Hall?

 

[5gn-h3t]

 

[Babyjohn460]

[emoji849][emoji1303]


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[scoreh3]

Rod Hall's I5 H3 has been ruling Baja for years ...