# Quieter HP gains...



## GTO BEN (Feb 5, 2011)

What would be the best upgrades to look into to grab some more HP without making the car any louder. I have an 06 M6 and it has corsa sport catback on it already and short throw shifter, but thats it. It sounds good but I am already concerned about noise with neighbors/cops and I want more of the sleeper shock when I blow someones doors off. I even debated putting the stock exhaust back on, but I really like the corsa so I am torn. Since this is my DD I dont want any unreliable mods, anything that will kill my MPG, or take down the life of the car either. Are there any quiet but high performance cams for this? Or should I look more the heads? Or is there something else I should look into? I guess I dont really need the HP since this is a DD, but I do want it...


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## svede1212 (Nov 1, 2005)

Change the exhaust to something quieter. You could sell that one and get something more reasonable for the same or less. Most significant HP gains flow more air and those make more noise. Heads would be well down my list. LT headers should always to the first mod for the subsequent mods to gain the most HP. After the LTs then a cam and intake would be my followup mods. With LTs (~25), cam (+60) and intake (~15) you could pick up close to 100 RWHP. Don't be too swayed by the 60 that I quoted for the cam as just dumping one of those in without headers would not get you that. It all works together.


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## jpalamar (Jul 22, 2008)

Weight reduction and nitrous.


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## GTO BEN (Feb 5, 2011)

svede1212 said:


> Change the exhaust to something quieter. You could sell that one and get something more reasonable for the same or less. Most significant HP gains flow more air and those make more noise. Heads would be well down my list. LT headers should always to the first mod for the subsequent mods to gain the most HP. After the LTs then a cam and intake would be my followup mods. With LTs (~25), cam (+60) and intake (~15) you could pick up close to 100 RWHP. Don't be too swayed by the 60 that I quoted for the cam as just dumping one of those in without headers would not get you that. It all works together.


Thanks for the info! Yea. I mean I thought about going to a quieter exhaust, but I really like the sound so its tough. I cant do LT... stupid California crap... I wanna keep it legal and smog-able. That also really limits my cam choices. When you say intake are you talking CAI? I feel like i have read on here or one of the other forums for GTO's that those dont really add much in gains... maybe I am wrong about that though. Also can I ask why not heads? Is it because of the money vs gains? I would like to get to 400 rwhp. Havnt put mine on a dyno yet so i dont know its at now, but I think i read a stock is close to 330 stock. Maybe I am wrong there too tho.


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## GTO BEN (Feb 5, 2011)

jpalamar said:


> Weight reduction and nitrous.


Trying to keep it CA legal and I would like constant power so nitrous isnt really for me. Thanks though. Weight reduction is a very interesting topic to me. Not sure what kind of gains can be had without affecting the drivability of it. This is my DD so what little comforts are afforded to me in the GTO are welcomed. Also I feel like this could get very expensive very quickly...


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## svede1212 (Nov 1, 2005)

The 243 heads are reasonably good so it's usually the last thing you do. 400 and smog legal is going to be tough the NA way. It could be done with a CAI (yes it can help), 100mm MAF, FAST manifold, a baby cam, shortie headers and a really good tuner. Even then the inspector may know that the MAF or whatever doesn't have a CARB approval.

Some models of Magnacharger or STS turbo are the only other thing I can think of that could pass and keep the drive-ability, mileage and all that stuff you need.

One more thing. Put a set of gears on it and you'll feel more acceleration.


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## GTO BEN (Feb 5, 2011)

svede1212 said:


> The 243 heads are reasonably good so it's usually the last thing you do. 400 and smog legal is going to be tough the NA way. It could be done with a CAI (yes it can help), 100mm MAF, FAST manifold, a baby cam, shortie headers and a really good tuner. Even then the inspector may know that the MAF or whatever doesn't have a CARB approval.
> 
> Some models of Magnacharger or STS turbo are the only other thing I can think of that could pass and keep the drive-ability, mileage and all that stuff you need.
> 
> One more thing. Put a set of gears on it and you'll feel more acceleration.


Thanks. Any suggestions for baby cam? Also what gears you recommend? Just found out it has a ported throttle body too. Not sure that is really going to pick up much in the way of power though.


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