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Alpha Exhaust... BIG DISAPPOINTMENT! - Page 2

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ALPHA XY
2/10/2008 11:00:14 AM
I like that set up, but not sure how much room is there to run the driver side strait out? Has anyone seen (at least on the Alpha) what GM did to get the pipe over to pass side pipe???? I've gotta take a picture of this?!
importkiller
2/10/2008 11:02:11 AM
there's no spare tire back there or fuel tank, should be easy to bend a pipe across to that side.
TheGunnyRet
2/10/2008 11:03:59 AM
It sounds like the exhaust on the mid 90s Mustang with the 4 cats right after the exhaust manifolds.
Resonators usually come after the muffler, if the're before the muffler then there is not much to them and act more like an expansion chamber.
If you have O2 sensors forward and aft of the cats then you will have problems with hi-flow cats with the CEL.  
You might want to give it some time before chopping up your exhaust, I mean the Alpha just came out. Pics would help greatly though.
importkiller
2/10/2008 11:08:21 AM
that's not really true about resonators coming after the muffler.....ALL import cars that have the can muffler at the bumper have a resonator near the rear axle. Same thing on the old chevy beretta, there was a cat, resonator then can muffler at the bumper. Most cars with rear mounted mufflers have a forward mounted resonator...look at the link Doc gave for the I5 exhaust and you'll see a forward mounted resonator then the rear mounted muffler.
rhill20
2/10/2008 11:17:15 AM
quote:

ORIGINAL: importkiller

quote:

ORIGINAL: rhill20

Would there be a reason NOT to go with the Dual Extreme? The one where the tailpips come out on the sides (one on each side). Was thinking (I have one of those trailer hitch baskets) that it would be better so as not to melt my cover on the basket carrier.


kinda like what I had on my Dodge
I like that setup...looks cool IMO


That's exactly the one I'm talking about.
 
 


Thumbnail Image
TheGunnyRet
2/10/2008 11:37:53 AM
quote:

ORIGINAL: importkiller

that's not really true about resonators coming after the muffler.....ALL import cars that have the can muffler at the bumper have a resonator near the rear axle. Same thing on the old chevy beretta, there was a cat, resonator then can muffler at the bumper. Most cars with rear mounted mufflers have a forward mounted resonator...look at the link Doc gave for the I5 exhaust and you'll see a forward mounted resonator then the rear mounted muffler.

 
So I guess this was a figmant of my imagination on my recent 2007 Dodge. You can't say something is not really true because different MANUFACTURERS have DIFFERENT configurations. Not all Imports have that either my past VW Golf, VW Passat, Suzuki Sprint Didn't. I can see why some members get annoyed.  
importkiller
2/10/2008 12:08:37 PM
WOW...talk about taking chit too seriously...chill out bro. you notice how we were all having a nice discussion until you took things too  seriously?and this is my fault....amazing.
 
you made it sound in your post that most resinators are post muffler...that is just not true. Sure I may have exagerated but nothing I said was meant to get into an arguement with you. There is really nothing to argue about..... there is a pre muffler resinator in the I5...that is a fact. Nothing to argue about
Doc Olds
2/10/2008 12:13:10 PM
The alpha has a set of maifold CATs way up front just like darn near every GM made now does for the early start up emissions concerns because they heat up quick.  The second CATs are the ones you should be able to replace with high flows if you are making a system.  The front ones are monitored.  I would double check that the CATs in the pipe are not.
 
This thread was started to express disgust in a system attempted to be made with parts of an 02 Trans Am Magnaflow sytem/the muffler.  Hardly tuned by Magnaflow for an 08 Alpha.  So we cannot conclude the apples to oranges comparison is really justification for chopping up the stock system just yet.  The Alpha will have systems MADE for it available soon, it is only February people. 
Doc Olds
2/10/2008 12:19:51 PM
quote:

ORIGINAL: rhill20

I wish I had about 2 grand laying around. Exhaust, hilljobs roof rack, PCMforless, Granetelli MAF.  Oh yea, the atlas transfer case too. Guess I should wish for about 4 grand

 
 
Granetelli MAF....?    No apps for the H3, yet?  I bet they won't have one for the I5 because their snake oil claims won't work with the stock configuration MAF placement.  A PCM tune can do the same stuff.
TheGunnyRet
2/10/2008 12:28:41 PM
Maybe it was the "that's really not true" and "All" part that kinda set me off because of the few Brands you might have dealt with and if you notice I said "usually". I try to generalize because I know that not ALL manufacturers are the same and I haven't had experiance with all of them either. And yes I know the I5 has one before the muffler.  
rhill20
2/10/2008 12:30:59 PM
quote:

ORIGINAL: Doc Olds
quote:

ORIGINAL: rhill20
I wish I had about 2 grand laying around. Exhaust, hilljobs roof rack, PCMforless, Granetelli MAF.  Oh yea, the atlas transfer case too. Guess I should wish for about 4 grand

Granetelli MAF....?    No apps for the H3, yet?  I bet they won't have one for the I5 because their snake oil claims won't work with the stock configuration MAF placement.  A PCM tune can do the same stuff.

 
Thanks Doc, wasn't aware that they were "snake oil". There are so many out there that are, kind of why I mention these things in passing hoping that someone will say something. So the PCM tune will do the same?
alphadogg
2/10/2008 12:39:29 PM
Well I had gone out to the garage to make room for my Alpha so I could get in out of the weather for the purpose of taking some pictures of the exhaust system to post but now I'm more confused then ever! You guys are arguing about mufflers & resinators on the Trans Ams, Mustangs, Dodge Trucks, imports, VW Golf, VW Passat, Suzuki. All I wanted to know about was the friggin' H3 Alpha. I'm not sure I want to get involved. Sorry but I think I'll sit this one out.
TheGunnyRet
2/10/2008 12:45:55 PM
Jet has a Hi-flow MAS for GM 5.3. I do know the MAC CAI has a replacement 72.5mm MAS replacing the stock one on the I5 but I think that is the same size as the stock one. Why you want to put an 02 TransAm muffler on a Alpha seems usless to me.
 
Only 2 of us are arguing, and I am done with that as well. I am just noting that there are many exhaust configurations and basing our analysis on what has been said and reference past experiance on the given.  
importkiller
2/10/2008 1:10:34 PM
quote:

ORIGINAL: alphadogg

Well I had gone out to the garage to make room for my Alpha so I could get in out of the weather for the purpose of taking some pictures of the exhaust system to post but now I'm more confused then ever! You guys are arguing about mufflers & resinators on the Trans Ams, Mustangs, Dodge Trucks, imports, VW Golf, VW Passat, Suzuki. All I wanted to know about was the friggin' H3 Alpha. I'm not sure I want to get involved. Sorry but I think I'll sit this one out.

 
seriously, if that little arguement is enough to keep you out of the discussion then your not long for this site. There are always gonna be disagreements...that's all that was. I have no hard feeling and I'm sure the gunny doesn't either....good lord, it was just a little arguement.
 
There is nothing to be confused about...the I5 has a cat in the exhaust manifold that are monitored, it has a cat after the manifold collectors, under the passenger seat area...then it has a resonator, then has the rear mounted muffler. I assume the alpha is the same as GM runs this setup alot of thier trucks. So the alpha would have two manifold cats, then an inline cat then a resonator then the rear mounted muffler. A picture would ice what kind of system it really does have though.
 
 
now post pictures of the exhaust. 
TheGunnyRet
2/10/2008 1:30:29 PM
I agree, if you want our advice we can't help by guessing.
Patches
2/10/2008 2:22:14 PM
I would have put my Alpha on my lift to get some better shots but it's too cold to be shuffling cars on and off the lift today so I just settled for crawling under and getting the following shots.
 
The driver's side "pre-cat" or "pup-cats" as they are also known.  There is one of these coming off each of the exhaust manifolds, driver and passenger, just after the O2 sensor.  The pup-cats light off faster than the main cats to keep cold start emissions low.  I'm not familiar enough with the H3 to know if it also uses an Air Injection Reation (AIR) system to pump fresh air into the exhaust stream on cold starts to reduce emissions until the cats warm up enough.  That air is injected for only the first few minutes of a cold start.
 

 
Here's the passenger-side O2 sensor there are two, one on each exhaust manifold collector.  These are essential to the operation of the engine as they monitor air/fuel ratio and allow the PCM to constantly adjust fuel injector pulse width and try and maintain as close to stoichiometric (14.7:1) air/fuel ratio as possible except on wide-open-throttle (WOT) where Power Enrichment (PE) mode is enabled which is essentially just a rich mixture for safety.  GM, as far as I know, uses only narrow-band sensors so they cannot be used for tuning purposes.  Wide bands have to be added (as I do on my vettes) in order to be able to tune the car using one of the sw/hw packages available.
 

 
Here you can see the relationship of the driver's sensor to the pup-cat (shot taken pointing towards rear of rig).
 

 
Both sides continue back to a main cat, one of which can be seen in the pic below.  Surprisingly, there is no secondary, colder O2 sensor behind each of these cats.  It's surprising because the rear O2's in other GM setups like my vettes monitor the operation of the rear cats and report an emissions DTC if one or both fail due to clogging or other problem.  The tuning software allows these sensors (their trouble code generators, really) to be shut off so that they can be removed or replaced with a high-flow aftermarket version.  This means none of the 4 cats is monitored by the PCM.
 

 
The exhaust then continues rearward where the two sides meet up and merge into a single pipe.  The driver's-side flattens out for a short distance before the Y to traverse and clear one of the crossmembers where there's not enough room for the round pipe to pass.
 

 
The single pipe is interrupted at this point, just after the Y by the resonator . . .
 

 
. . . and then continues over the passenger-side rear axle to the muffler.
 

 
The exhaust gasses exit the muffler out the driver-side-only tail pipe.
 

 
It seems that running a true dual exhaust will be a little bit of a challenge due to the fuel tank that blocks access to the driver's side.  Dual is still possible but would be circuitous as the driver's side makes a detour around the tank.  An x-pipe section could be placed further back, possibly in the area where the resonator currently resides.  Clearance for heade
importkiller
2/10/2008 2:36:46 PM
So a true cat back would remove the resinator and rear mounted muffler...that would open up the sound a good amount I would think. Having no downstream 02 sensors also helps cause you can replace the back cats to a highflow cat if you want to really open it up....good stuff...thanks for the pics!!!
alphadogg
2/10/2008 3:51:46 PM
Patches,
I just signed on to post some pictures but alas you beat me to it! Thank you very much for the great shots as I know how difficult it was to get a decent shot without lifting the truck. Now we all can be enlightened.
alphadogg
2/10/2008 4:15:13 PM
quote:

ORIGINAL: importkiller
seriously, if that little arguement is enough to keep you out of the discussion then your not long for this site. There are always gonna be disagreements...that's all that was. I have no hard feeling and I'm sure the gunny doesn't either....good lord, it was just a little arguement.

 
mr. importkiller,
I have been around enough forums to see "little arguments" like that turn into nasty full blown wars and not knowing the relationship between you and TheGunny I did not know what direction that was going so I simply did not want to be involved. I'm at a point in my life that I don't need to prove anything to anyone and don't need any stress or BS from anyone either. Everyone here has been a great help to me but I certainly don’t expect anyone to get their shorts in a knot over something I’ve asked about. Thanks for all your help.
 
Gar
importkiller
2/10/2008 5:05:35 PM
not to worry bro...we are all cool here. Even when arguments get really heated (and they have before) we always seem to find a happy zone and calm down. Normally it takes Bob posting something funny to bring us around but we hardly ever leave with hurt feelings. I have much respect for the gunny and his knowledge and my intent was not to hurt his feelings...I don't think he feels that way but if you do Gunny, I am sorry. I admin two boards currently and mod two others and this is the only place where almost everyone is man (or woman) enough to be able to have a productive argument where name calling and personal attacks never come into play. Hell, 75% of the arguments here that get really heated are by long time members that are just messing with each other. Some of the old arguments I had with shorty you would of thought we wanted to kill each other...but in the end Shorty is probably my best friend on the board and someone I respect a great deal. It's all good brudda
ALPHA XY
2/10/2008 5:51:06 PM
the flattening out of the driver side pipe to cross under the x-member is what I was at when I was under there today?? Don't you think that interrupts flow making for an unblanced exhaust pluse?

All the cats and res's/goofy bends, Nissan Z esque muffler......we have to figure out something better guys! :)
importkiller
2/10/2008 6:06:02 PM
the I-5 has the same flattened out section of pipe. I don't like the design either. There was a member here awhile ago that redid that part of the exhaust after he did a cat back and said that he noticed no improvements. Coming out with something better definately couldn't hurt any though.
TheGunnyRet
2/10/2008 11:16:42 PM
Man, what a mess. Everything after those cats is just sound reducing resonators or whatever you want to call them.
 
Here is what I think, I would see if the MAC GM 5.3 Headers fit, look at Dr Gas for an X-pipe that has a 90 degree bend off one leg then run that to a Spintech dual in and out and split them out the back.
 
The other thing you could do is volunteer your Alpha to one of the major Exhaust Makers if you live close to them.  
alphadogg
2/11/2008 4:07:41 PM
I agree with TheGunny, what a mess! When I have the extra coin I'm going to replace the mid-truck resonator and install a hi-flow muffler in it's place, then some how with dual tailpipes exit out the back. There's a muffler shop in my hood that does custom work (bending etc.) and might be up to the task. I'll go by and see what the muffler shop says and let everyone know what the verdict is.
Alpha Offroad
2/12/2008 8:08:51 PM
Regardless the alpha has 4 cats. How many time does a man have to say it. I talked to a g.m. tech and he told me their monitored before the first cat and after the second cat. And removing or altering any of them could cause you to throw a o2 code. My only option with removing the pre-cats it to park my alpha,core my ecu.and get a new comp. tune to accept the loss of backpressure and possibly advance spark,time.,air,fuel, but you hafta run 91oct. Or get o2 simulators---  they make them for late model muscle cars.
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