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Down pipe

J

JB Miller

New member
I was intrested in a ubend delete so I am thinking about getting a 3" downpipe and have read it will add about 10 hp to my 00 gp gt. Now this might be a noob question but is what is the difference in wether it has a cat or not? Also does anyone have one they are trying to sell?
 


i am aslo a noob at exaust and am looking for a few answers about d.ps. I was also wondering to bolt up to a stock exaust what would be the best dp choice of zzperformance just untill i get some more cash for the to finish the cat back at a local shop.
 
A cat is necessary for passing emissions, so if you live in a county where you have to have your car emission tested then get a DP with a cat. If you have a GT then the 2.5" ZZP catted DP will do you just fine, if you have a GTP then the 3" would be a better choice. hope this helps...
 
GTP: 3" Catted or not...maybe 1hp difference IF that.
GT: 2.5" Probably get rid of the cat...GT's need all the power they can get :p

And for the stock exhaust...yes...that is what a "bolt-in" downpipe is.
 


Yea I am leaning towards a 3" with cat because i do need to go through emissons again in august. It seems my alpine stereo is messing with my obdII and will not communicate with the emissons computer, still dont know what I am going to do about that. Any ideas?
 
ohk thanks guys i think im going with the 3dp with no cat since i dont hook up to an emissions system, just got to get a dummy 02 sensor. but however in nys its illegal not to have a cat but since im a nys inspector no worries there:D
 


Yea i think the guy that put the stereo in tapped into the wiring harness dont know much about electrical work so im probly gonna just take it to bestbuy. And I think im gonna go with a 2.5 dp with cat as I do need to pass emissions in MD as they are really strict and I want to keep my low end torque.
 
Yeah I just put a 3" with no cat on my gtp and it made it sound deeper. I liked it. Zzp also sells those o2 emmulators if u plan on not runnin a cat. Tell us how it goes bro
 
JB Miller said:
Yea i think the guy that put the stereo in tapped into the wiring harness dont know much about electrical work so im probly gonna just take it to bestbuy. And I think im gonna go with a 2.5 dp with cat as I do need to pass emissions in MD as they are really strict and I want to keep my low end torque.
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lolz best buy. Being a former bestbuy installer, i strongly recommend taking it elsewhere. There is no reason why the headunit would be tapped into the pcm. Open it up the dash, look at the back of the head unit, there should be a harness adapter going into your factory harness for your radio. I really don't see the point of a 3" dp for a N/A gt, unless u plan on top swap in the future...I could sell u my zzp 2.5" catted dp, since I want headers now.
 
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Well that is what the emissons ppl told me when no communiction occured with my obdII but idk im sure ill fiqure it out. Yea i understand the 3" is unecessary for a n/a 3.8. How much would you want for the zzp 2.5 w/ cat?
 


It is a pretty arguable topic recently but a 3" won't HURT your n/a car it just might be a little too big. I'd still get it, especially if you never get headers and want to do rockers or a cam. That 3" will out shine that 2.5" then IMO.
 
I mean a 2.5 is cheaper and im a teenager so im on a budget. Also I already have a fwi and dont really plan to do more after a downpipe and intense pcm hopefully by this summer
 
Colder Thermostat and plugs are cheap mods...about 20 bucks for both. And they help with cooling the motor too.
 
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