UPGRADE to Alpha? Another Header thread

[humvee]

I'm thinking of trading in my i5 for an alpha for that extra power. Displacement is needed, but I'm not so keen on the gearing ratio.

Problem is, I've already invested so much time & $$$ fixing up the i5... Catback, intake, PCM tune.. The only thing missing are headers, and perhaps a ported throttle body.

With the 35's, my truck still struggles a bit in the low rpms... and I need to know if headers are worth it!

I guess it all comes down to these two questions:

1) Will headers make my engine suffer in low rpm range? (mesablackworks to be precise)

2) Does anyone have a 0-60 before and after headers on 35's?

Any sort of feedback would be great.

 

[SuperBuickGuy]

depends on the header - but with that said, I've yet to have a motor that didn't like the extra breathing absolutely everywhere

 

[MaxPF]

You can put a set of zoomies and a flying toilet in the I5 and it's still going to be a 3.7L motor. When it comes to low RPM torque, which is what you really want along with more power, there's no replacement for displacement.

 

[06 H3]

how far are you into your project? For me, upgrading to an alpha is not worth it. I have too many mods in general and specifically too many non removable mods to transfer to an H3 Alpha. I just live with the I5, when it blows up hopefully I have the cash to upgrade.

 

[MaxPF]

I just live with the I5, when it blows up hopefully I have the cash to upgrade.

Something like a 6.2, 4L80 or 6L90, and an Atlas?

 

[Snakecharmer]

I put header(s) on my 2006 and it made a significant difference. However, I think it needs a PCM tune because it seems to be struggling to reach the right gear before it gets to 50 mph. I now have an Alpha. It's much better on the low end. I have not tried the zoomies or flying toilet yet, but it's on my list of future mods.

Whether it is worth it or not depends on your disposable income. Very subjective, but it does make a significant difference. My 2006 is for sale for a very reasonable price. I suggest you buy it and try out the headers and decide for yourself.

 

[MaxPF]

I have not tried the zoomies or flying toilet yet, but it's on my list of future mods.

:giggle:

 

[amrg]

I haven't tried the flying toilet either! Maybe the zoomies when I was searching everywhere for every bit of hp to give to my old 3.5L I5

 

[humvee]

how far are you into your project?

You have a brilliant truck, I haven't done half the work you have, and I don't intend to take it much further. Its my daily driver.
As far as non swappable mods go, there's only the catback and airdoc... Other than that there's the bodylift, I'd rather just buy a new one and save 50% of the work.

PCMofNY are still working on my tune, they said I should be satisfied with my low rpms when they're done.

I have not tried the zoomies or flying toilet yet, but it's on my list of future mods.

:eek Thanks!! Let me know how it runs... cz I really gotta go
:hfalls:

 

[Blake-O]

You have a brilliant truck, I haven't done half the work you have, and I don't intend to take it much further. Its my daily driver.
As far as non swappable mods go, there's only the catback and airdoc... Other than that there's the bodylift, I'd rather just buy a new one and save 50% of the work.

PCMofNY are still working on my tune, they said I should be satisfied with my low rpms when they're done.





:eek Thanks!! Let me know how it runs... cz I really gotta go
:hfalls:

What does the PCM tune generally run? I'd like to get mine adjusted now that I've done the cat back, airdoc, and 35"s. Thanks.


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[humvee]

What does the PCM tune generally run? I

They play around with your truck's parameters, e.g: Your stock computer is programed to sock airflow and tires etc.
With a custom tune, your truck would be programmed to accommodate the changes that your upgrades brought (more air flow into the engine, more airflow out).
They can even play around with your shift points, and shift firmness, amongst many other things.

Check out PCMofNY, According to this forum and others, they're the best choice for Hummers. I should be getting my tune today, I'll post up some feedback.

 

[humvee]

Guys, anyone else care to chime in on the headers? Possibly someone who has them installed.

 

[Steve #1]

I'll also say that it depends on the header. You will want short tubes to maintain as much back pressure as possible, and at that point the benifit of the header is going to be getting heat away from the motor. It could help, but could also hurt your low end which is what you are trying to help.

 

[hockeymanam]

i have the magna flow header installed on my 06 3.5 with a pcm tune and honestly i could not tell any gain in power just a nice drone added to already having exhaust and 35 MT. i got the header just bc my other one fell apart at the CAT. I did not get my pcm retuned since i got the header but, i can't imagine making much of a difference. I you want more power and you think a header is going to save you I'm sorry to say you will be disappointed and have sunken more money into something that you will still want to trade in for an alpha.

 

[06 H3]

You have a brilliant truck, I haven't done half the work you have, and I don't intend to take it much further. Its my daily driver.
As far as non swappable mods go, there's only the catback and airdoc... Other than that there's the bodylift, I'd rather just buy a new one and save 50% of the work.

PCMofNY are still working on my tune, they said I should be satisfied with my low rpms when they're done.





:eek Thanks!! Let me know how it runs... cz I really gotta go
:hfalls:

Thank you, I greatly appreciate it! I would wait to see what the tune does, supposedly it helps alot.

i have the magna flow header installed on my 06 3.5 with a pcm tune and honestly i could not tell any gain in power just a nice drone added to already having exhaust and 35 MT. i got the header just bc my other one fell apart at the CAT. I did not get my pcm retuned since i got the header but, i can't imagine making much of a difference. I you want more power and you think a header is going to save you I'm sorry to say you will be disappointed and have sunken more money into something that you will still want to trade in for an alpha.

Thats weird, The colorado guys have dyno proven results with headers claiming 30hp on the dyno...Not the seat of your pants testing.

Something like a 6.2, 4L80 or 6L90, and an Atlas?

Sounds about right! I gotta take care of that front end first. :cheers:

 

[chaos254]

The magna flow looks like a stock replacement, most people adding aftermarket headers are installing ones without the first cat.

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[hockeymanam]

Thats weird, The colorado guys have dyno proven results with headers claiming 30hp on the dyno...Not the seat of your pants testing.

30hp gain from just headers in a 3.5 hummer engine? i can't imagine that much gain from header, exhaust, pcm, and intake combined!!! I do wish i picked up 30hp that would of been awesome!! I feel like if i gained that much power i would of noticed it, but how fast can you really make a box on mud tires go?

 

[humvee]

Thanks for the input so far. The Magnaflow headers are known to be useless, built with a CAT to maintain emission standards.

I'm surprised that there weren't any real results for these headers on hummer forums. Since the AWD dynos aren't available everywhere, I was hoping to find some 0-60 figures at the very least. I know its not much, but its definitely better than this:

This is the most helpful post I found on another forum:
"installed!!! I used the extension, medium port size. Great results!!! Great sounds! Perfect!" :huh:

Most people just went on about how they were pulled back into their seats at full throttle... And that sort of feedback is totally useless.


This wouldn't be a problem if I lived in the States, but it costs $750 to buy the thing, and another $700 to ship it here! And $900 to ship it back in case it was junk.

I'd love to hear some feedback from members who have it installed.

 

[chaos254]

Thanks for the input so far. The Magnaflow headers are known to be useless, built with a CAT to maintain emission standards.

I'm surprised that there weren't any real results for these headers on hummer forums. Since the AWD dynos aren't available everywhere, I was hoping to find some 0-60 figures at the very least. I know its not much, but its definitely better than this:

This is the most helpful post I found on another forum:
"installed!!! I used the extension, medium port size. Great results!!! Great sounds! Perfect!" :huh:

Most people just went on about how they were pulled back into their seats at full throttle... And that sort of feedback is totally useless.


This wouldn't be a problem if I lived in the States, but it costs $750 to buy the thing, and another $700 to ship it here! And $900 to ship it back in case it was junk.

I'd love to hear some feedback from members who have it installed.

At those prices, can't you have someone local make you a header?

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[humvee]

At those prices, can't you have someone local make you a header?

Not in Doha... custom jobs cost an arm and a leg... And no one here does that sort of stuff anyway.

Just to put things in perspective... You guys put a man on the moon, over here they just discovered all-terrain tires.

 

[digglesworth]

I've heard you can gut your stock cat for an extra 10hp and it won't throw codes.

 

[rsc]

I've heard you can gut your stock cat for an extra 10hp and it won't throw codes.

Only for the 06's. 07+ need some slight trickery to fool the sensors, nothing big.

 

[SuperBuickGuy]

I've heard you can gut your stock cat for an extra 10hp and it won't throw codes.

you can turn off the O2 sensor with HP tuners, no codes - but again, if you're worried about back pressure, remove the mufflers and run a straight pipe from the cat to the tailgate.... trust me, the mufflers add the equivalent of at least 20' of pipe worth of back pressure.

these are the inside of side pipe inserts; but most mufflers look like this on the inside






it enters on the left, goes to the outside through those slits, then back inside at that cap, then outside, then through the fiberglass batting and out of the muffler.... the cat is designed to be a flow-through (not pellets like the first gen of cats) honeycomb.... very little restriction, it works by heating the air and reburning the exhaust....

 

[digglesworth]

Only for the 06's. 07+ need some slight trickery to fool the sensors, nothing big.

Has anyone actually done it...?

 

[MaxPF]

you can turn off the O2 sensor with HP tuners, no codes - but again, if you're worried about back pressure, remove the mufflers and run a straight pipe from the cat to the tailgate.... trust me, the mufflers add the equivalent of at least 20' of pipe worth of back pressure.

Depends on the muffler. You can see straight through the Magnaflow I have on my truck. It has no protrusions of any kind into the exhaust stream.