H3 HI-Flow Catalytic Converter

[H3HummerLineX]

Hello Guys, I'm looking into Hi-Flow cat's. I'm hoping this will give me a little performance boost.. Any recommendations?

FYI I'm in a very smog friendly state. lol California!

Thanks in advance.
Jeff

 

[Best4x4]

Magnaflow makes them for the I5. They come in two versions CA emission certified or 48 state certified. If u have an Alpha with the 5.3L I'm not sure what u can get.

 

[SolidusJ]

Hello Guys, I'm looking into Hi-Flow cat's. I'm hoping this will give me a little performance boost.. Any recommendations?

FYI I'm in a very smog friendly state. lol California!

Thanks in advance.
Jeff

It's a HUMMER brother not a corvette. You could check out a tune, polished TB and spring delete for the coils to help it along to move it but in the end she's a fat brick on wheels.

 

[Best4x4]

Yeah I find the 3.7L fine once up to speed. It will not win any drag races but it moves the H3 around better than a 4.0L or 3.8L Jeep 6 cylinder.

 

[rascole]

Replacement cats are far and few between for CA. Even worse for the I5, only a couple are 50 state legal. Besides, not much to gain power and it may rob low end torque if not set up correct, opposite of what you want.

 

[Best4x4]

Yeah Magnaflow is the only one I'd trust vs OEM.

 

[H3HummerLineX]

LOL.. Big fat brick for sure. Just looking to squeeze all the power I can out of it and the cats already a suspect of being clogged up.
So I if im going to need to replace it I was thinking of going with a hi-flow unit.


Magnaflow will be my choice think..

 

[alrock]

Well, the second cat on an 07 isn't monitored by the 02 sensors so you could cut it out and replace it with straight pipe. It would pass emissions if all they do is hook up a code reader to the truck. Not sure of the legality of it, that you'll have to research. But removing it would surely clear up any clog in that cat.

 

[4speedfunk]

I'm with Solidus. Why put a high flow cat on a low flow motor? When it comes to the H3...the best motor mod u can do is: leave it alone and pray nothing goes wrong with it.

 

[derian06]

Exhaust, tune, super sparks coil delete, ported throttle body, iridium plugs, synthetic oil, cold air intake, trans cooler, dual efan, and you're ready to go.

 

[4speedfunk]

And just think....all of that netted you a whopping 5 hp gain, cost you a grand, voided your all-ready useless warranty, and gave you occasional Check Engine lights.

I ain't touching mine. :no:

 

[rascole]

And just think....all of that netted you a whopping 5 hp gain, cost you a grand, voided your all-ready useless warranty, and gave you occasional Check Engine lights.

I ain't touching mine. :no:

Ditto

 

[Best4x4]

Just slap a K&N sticker on it, that's a 10HP gain right there!!

 

[H3HummerLineX]

Thanks for all the info guys. Really appreciate it.

Looks like it's the second cat that is bad. This could also be one of the reasons my rig is running a little hotter than normal.

 

[derian06]

Just slap a K&N sticker on it, that's a 10HP gain right there!!

Don't forget the throttle body spacer and the racing stripes!

 

[digglesworth]

i have an airdoc intake, spring deletes, p+p throttle body and a pcm tune. costs me 5-700 bucks or something like that... it runs better now with 35s than it did before with 33s. and i get anywhere from 16-20mpg... thats about all ill do to it power-wise...

 

[4speedfunk]

I'll admit, I have the AirDoc and a PCM tune. The PCM tune had more to do with tire size & gearing correction and shift points...than actual performance.

 

[amrg]

Dont forget, H4O stickers are a proven performance booster (some say you get 10 extra hp just by joining this forum!!!)

 

[H3HummerLineX]

Dont forget, H4O stickers are a proven performance booster (some say you get 10 extra hp just by joining this forum!!!)

If hats the case please send me 10 stickers.. lol