Hey guys, I'm for certain picking up GMS1 this summer, and I'm also thinking about getting a downpipe but the real question is if I add the downpipe after GMS1 will I notice any gains? I've searched the forums and I'm getting alot of conflicting opinions, some say there will be a noticable difference and others say that modding ontop of GMS1 is pretty pointless and that the best setup is just to stay stock w/ the GMS1. Since I haven't been able to find a definative answer I figured I'd throw it out there and see if I could get some feedback from people who have actually been there, done that.

Little background info for the wondering minds out there, I have a 2010 White SS Turbo w/ 1300mi on it. Wanting to go GMS1 with a Hahn catted dp.

 

First of all , the factory D/P has two cats in line....this is a restriction of exhaust.....now replacing the pipe with one with no cats will create much faster spool up of the turbo.....using a catted after market pipe will still be compliant with state regs but will free up hp. I have stage 1 and installed a new complete system today with catted D/P....the results are excellent...the down pipe is one of the best mods to make.

 

What does excellent mean? Do you have a before and after dyno?

Dog

 

[QUOTE=meldog21;4851039]What does excellent mean? Do you have a before and after dyno?

Dog[/QUO

Yeah, dyno by sotp......the car unquestionably has more power.

 

Can you link a pic of the dyno? Very interested in this.

 

I am also very interested in seeing some before and after numbers, I've heard a lot of people raving about how much of a difference gms1 and a dp makes, I'm just curious exactly how much.

 

It def made a hell of a dif with the sc tune dont see why it wouldnt with the gm tune.

 

Hey man, I have the GMS1 and just recently installed the hahn s.steel catted downpipe and although I do not have any dyno numbers,I will def tell you that the d/pipe was worth the money,the car really pulls and spools up much quicker.hope this helps.

 

Awesome thanks alot! Did you notice any noticable sound difference after you put it on?

 

Of course it will be louder , you are removing restriction that muffles ,the sound note will be determined by what is behind the D/P.

 

I don't have dynos but I ran it at the track before, with just GMS1 and ran a 13.67. Last weekend I ran a 13.40 with a very similar 60' time but now I've got a CIA catted downpipe and the ZZP airbox mod. So there are some hard numbers to show you the difference. As far as feel - it feels stronger throughout the rpms and definitely sounds more aggressive.

 

Nice! Well I'm definitely very excited to get the ball rollin on this. Anyone have ballpark/rough estimates as to what numbers should be seen from a setup like this?

 

As far as sound it sounds almost normal at idle,slightly louder but def louder once you put your foot into it.