Gmpp
02-23-2008, 07:24 PM
#26
hmm interesting well i was planning on going the ca route in the begginning but if i would get the gmpp if it gave close to the same results plus it would keep warranty on the exhaust manifold. if the ca header and xtc downpipe give the best gains and there arent any problems with them as far as fittting or cels then that is the route i will take. have u guys had any problems with cobalt addiction as far as shipping and whatnot because i have read posts im not sure if it was on here or g5club.net but some people say that have had some issues with getting there stuff.
GM claims the GMPP ext-honed manifold provides 7% more flow capability -- what that equates too in HP hasn't been figured out. IMO A header on our 2.4s is good for appearance (mostly hidden unfortuneately), the factory exhaust manifold is already fairly free flowing and not a "twisty-turny" flow-disturbing design -- it is very similar to a header. I would like to see an independent test of the headers - that are currently available - that proves the HP increase. I'm not stating headers are useless -- It's just that the 2.4 can work with the factory manifold or GMPP manifold considering the 2.0SC uses them very well and produces quite a bit more power.
02-23-2008, 07:28 PM
#27
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well that sux but the only time that would be a problem is when u have to get it inspected what do u do then? or is there a way to not get a cel, ive heard that u should unhook the battery when installing performance parts would that help not get one or are u screwed either way.
02-23-2008, 07:33 PM
#28
well that sux but the only time that would be a problem is when u have to get it inspected what do u do then? or is there a way to not get a cel, ive heard that u should unhook the battery when installing performance parts would that help not get one or are u screwed either way.
02-23-2008, 07:43 PM
#29
I have the GMPP ext-honed manifold and CED's 2.75" Random Tech cat-back exhaust (little loud for most areas). I was considering the 2.75" DP/converter but was warned that I would have problems with CELs unless I could tune. The factory DP is 2.25"
GM claims the GMPP ext-honed manifold provides 7% more flow capability -- what that equates too in HP hasn't been figured out. IMO A header on our 2.4s is good for appearance (mostly hidden unfortuneately), the factory exhaust manifold is already fairly free flowing and not a "twisty-turny" flow-disturbing design -- it is very similar to a header. I would like to see an independent test of the headers - that are currently available - that proves the HP increase. I'm not stating headers are useless -- It's just that the 2.4 can work with the factory manifold or GMPP manifold considering the 2.0SC uses them very well and produces quite a bit more power.
GM claims the GMPP ext-honed manifold provides 7% more flow capability -- what that equates too in HP hasn't been figured out. IMO A header on our 2.4s is good for appearance (mostly hidden unfortuneately), the factory exhaust manifold is already fairly free flowing and not a "twisty-turny" flow-disturbing design -- it is very similar to a header. I would like to see an independent test of the headers - that are currently available - that proves the HP increase. I'm not stating headers are useless -- It's just that the 2.4 can work with the factory manifold or GMPP manifold considering the 2.0SC uses them very well and produces quite a bit more power.
The stock mani looks like it should be on a toy.
Just because they are making more HP doesn't mean it is efficient.
I mean by all means choke your car out but seriously...but if the OP does decide to get the GMPP honed bullcrap just go to wal mart and buy a machining set and do it yourself and save yourself some serious money
If you have the back o2 sensor set to not give you error will you still fail emissions?
Last edited by steddy2112; 02-23-2008 at 07:43 PM. Reason: Automerged Doublepost
02-23-2008, 08:02 PM
#30
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"I have the GMPP ext-honed manifold and CED's 2.75" Random Tech cat-back exhaust (little loud for most areas). I was considering the 2.75" DP/converter but was warned that I would have problems with CELs unless I could tune. The factory DP is 2.25"
did u put them both on at the same time or seperate if separate did u notice any gain with just putting on the new manifold
did u put them both on at the same time or seperate if separate did u notice any gain with just putting on the new manifold
02-23-2008, 08:10 PM
#31
Have you ever seen any other aftermarket header compared to the stock mani?
The stock mani looks like it should be on a toy.
Just because they are making more HP doesn't mean it is efficient.
I mean by all means choke your car out but seriously...but if the OP does decide to get the GMPP honed bullcrap just go to wal mart and buy a machining set and do it yourself and save yourself some serious money
The stock mani looks like it should be on a toy.
Just because they are making more HP doesn't mean it is efficient.
I mean by all means choke your car out but seriously...but if the OP does decide to get the GMPP honed bullcrap just go to wal mart and buy a machining set and do it yourself and save yourself some serious money
02-23-2008, 08:13 PM
#32
I don't dispute you on the fact that a header has the capability to flow more than the GMPP manifold does -- that's a proven. It's just that the GMPP manifold provides more than adequate flow for a basically stock 2.4. The 2.4 does not push more air then a 2.0 yet the 2.0 engine is producing 30-70 more HP at a higher RPM all through the same manifold.
Hey like I said it is your car not mine...I suggest you hone and polish it yourself before you try to buy one though
02-23-2008, 08:14 PM
#33
"I have the GMPP ext-honed manifold and CED's 2.75" Random Tech cat-back exhaust (little loud for most areas). I was considering the 2.75" DP/converter but was warned that I would have problems with CELs unless I could tune. The factory DP is 2.25"
did u put them both on at the same time or seperate if separate did u notice any gain with just putting on the new manifold
did u put them both on at the same time or seperate if separate did u notice any gain with just putting on the new manifold
02-23-2008, 08:17 PM
#35
02-23-2008, 08:22 PM
#36
What are you talking about?
You can buy a honing kit at like home depot that you put on a dremel tool or a drill for like 50 bux TOPS.
Then you can either:
A) Have your car down for a day
B) Buy an SS manifold on here for no more than a 100 bux tippy tops
If you were talking about the cat back I would like to know who paid 800 bux for a GM exhaust so I can point an laugh until I die.
My touring was like 550
You can buy a honing kit at like home depot that you put on a dremel tool or a drill for like 50 bux TOPS.
Then you can either:
A) Have your car down for a day
B) Buy an SS manifold on here for no more than a 100 bux tippy tops
If you were talking about the cat back I would like to know who paid 800 bux for a GM exhaust so I can point an laugh until I die.
My touring was like 550
02-23-2008, 09:20 PM
#37
What are you talking about?
You can buy a honing kit at like home depot that you put on a dremel tool or a drill for like 50 bux TOPS.
Then you can either:
A) Have your car down for a day
B) Buy an SS manifold on here for no more than a 100 bux tippy tops
If you were talking about the cat back I would like to know who paid 800 bux for a GM exhaust so I can point an laugh until I die.
My touring was like 550
You can buy a honing kit at like home depot that you put on a dremel tool or a drill for like 50 bux TOPS.
Then you can either:
A) Have your car down for a day
B) Buy an SS manifold on here for no more than a 100 bux tippy tops
If you were talking about the cat back I would like to know who paid 800 bux for a GM exhaust so I can point an laugh until I die.
My touring was like 550
I meant $400-$800 for a header...i already have a GMPP Ex-Hon mani and cat-back exhaust
02-23-2008, 10:25 PM
#41
Still no header designs that you can use with the SAI (not that I've seen or read about
). There is a way to disable the SAI in the ECM by a GM technician but if you live in a state that requires it they probably won't turn it off -- IF you could find a dealer service department that would. The disable ability is in the same area of the ECM the dealer would go to when they install 16" wheels on a Cobalt equipped with 15" wheels -- I haven't seen it done personaly.
Last edited by Red07SSNA; 02-23-2008 at 10:26 PM. Reason: Automerged Doublepost
02-23-2008, 10:47 PM
#44
Yep, SAI is only on some 2.2s...................Cat-back first -- biggest restriction. Then header or GMPP. I read threads of owners installing a larger DP and they had problems with CELs because of the cat/converter H02S not reading what it is set for. Need to find out more about tuning before going with a DP.
02-05-2009, 11:29 AM
#48
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any dyno numbers?
i agree with Red's point of view. For me i just want a lil more kick in the ass and to keep my dealer and warrenty happy. The e-h mani works well on an engine that is moving way more air, so it should show gains on our 2.4's..... sure headers will flow much better but can a 2.4 with just an Intake and Catback taje advantage of thoes gains is the real qestions.
