I also have an 08 Alpha Superchips K&N and my exhaust is a cat back Gibson.
I love the combo, and I run my Superchips on the tow setting and my normal
driving gets me 16 mpg.

 

Yep, me too. Pretty much run in tow mode all the time now. Better mileage and highway power than any other mode.

 

Tainter: I'm glad to hear that out of you! I tried the other setting at one month intervals and by far was most satisfied with the tow for the same reasons as
yourself.

 

How do you like your Cat-back? I looked at the Gibson and magnaflow, I am leaning toward the Gibson.

 

tow tune actually feels much better, maybe it is all mental but with that tune the truck has a little get up.

 

I run my own design intake tube and a snorkle with SyKlone prefilter and I have a K&N I sometimes run on long road trips but not offroad in dusty conditions. I just use one of the many replacements for the stock filter for best filtration on the Alpha.


I use the superchips in tow mode on the Alpha because at 6600 lbs loaded for my travels I wanted the shift points changed, which is one of the changes it does but I run 87 octane with it most of the time. I wanted the options to change settings with the Alpha but I did use custom PCM programming on my I-5 but had a stock one I carried with me and for warranty inspections.
I also x'ed the muff on the I-5. That has less back pressure than any muffler I know of and did not have any adverse affects I could detect on the engine performance. All together gave smoother idle, faster response and of course unknown level of perfomance except by SOP dyno but I liked it! It also reduced the amount of downshifting on the I-5 in hilly terrain or towing.
Initial MPG will probably be reduced because of your right foot, but will eventually come up a bit.
Those changes help both engines but I have not messed with the Alpha muff.

 

I love the gibson and easy to install, and your right it my be mental but I agree.

 

I want to do some upgrades to the H3 Alpha so I'd like some opinions on a few things
1. Exhaust looking into a cat back
Gibson
Magnaflow
GM
Has anybody installed the GM touring or performance system that the dealer sells? I have read plenty on the Magnaflow and Gibson so I'm wondering about the GM system any thoughts?

2. Cold air Intake
Most of these are not really a CAI in my opinion, simply changing the intake tube,filter and air box and leaving it all in the engine compartment does not make a cold air intake. A cold air intake is suppose to draw air from an area outside the engine compartment where there is engine generated heat. The theory being that a cold air charge is denser than a warm or hot air charge. I haven't seen where the H3 systems accomplish this, they may increase airflow to the intake but I doubt its any cooler than the stock air-box system. That is without rerouting the whole intake system and I'm not sure there is a location to draw air from on an H3 that won't compromise the off road capability. So lets say increased air flow.

3. Ported and Polished throttle body

anybody had any success here? this seems like the best way to increase performance and add to it a higher flow air filter.


So I like to here all opinions

 

I don't know of anyone with a port/polished TB with the Alpha. I know where you can have them done, just haven't heard any feedback yet.

Re-read this thread. Good luck.

 

Ricky: Ummmm.....did you read this entire thread? By the way ALL H3s regardless of the engine (I5 and V8) get air from inside the passenger fender (OEM). There is a clear path to fresh cool (depending on the outside temp) air. Hence, the H3s already have a "cold air intake", now you just have to make that path as smooth as possible to the TB. That is why I have AirDoc CAI tubes on both of our HUMMERs.

As far as the "high flow" air cleaners, take a look at all of the research done lately on the "high flow" air cleaners VS a good dry media style. The Good dry media style filters better through the life cycle and flows about the same through the entire life cycle. Unlike the "oiled" type of performance filters.