with the code throwing issues, cant you guys use a defouler? or are you unable to with cobalts? with hondas we just use defoulers and bam, no codes... evar.

 

Have no idea the numbers..but I have the highest GMS1 dyno I've seen so far with Catted DP and Intercooelr upgrades (along w/ charge pipes, k&n filter, air box modification, and aem coupler from airbox to turbo). GMS1 netted a gain of 67whp/73wtrq over stock with the same modifications

 

You have a catted DP so of course you wouldn't have problems with codes...I'm catless...and anyone that's catless CAN get a code at any time...regardless of the "angled O2 bung." Like I said...my cattless was fine for nearly 10k miles...then bam while cruising home from work on the highway one day it just came on. Whether or not you throw a code is purely luck.

That being said...the catless ones can make slightly more power with a custom tune (Not a GM canned tune) mainly because of not having to worry about Cat Over Temp protection. Most modern High flow cats flow so astonishingly good it's silly. So flow is not really an issue (especially on a stock turbo)...it's the fact that you could melt the **** out of your cat and shoot bits of it out of your exhaust if you don't reduce the power by richening up your AFR (reducing power) when the cat reaches a certain temperature.

To sum it all up...if you only plan on going with the GM stage kit...you might as well go with a downpipe that has a high-flow cat instead of catless because the GM stage tune will NOT remove the cat over temp protection boundaries and WILL richen up your AFR on long pulls (1/4 mile, highway pulls, etc.) regardless of you being catless or not. On the other hand...if you're going with a custom tune and want to make a solid 10whp more...get a catless.

 

so it sounds like I will be in the market for a 3" high flow catted downpipe as jersey inspection has wonderful people!!!!

 

I've installed zzp catted last week, getting code every day. Got low voltage,inactivity and lean code. Removed it yesterday and my sensor was wet, it's winter time here.

 

Go with a 3" dp. Go catless if you can its the best performance option. If your area is really strict on the emissions, and there is no way for you to get around not having a cat. Have a local shop make you a custom 3"dp out of T304 USA stainless with a test pipe. Have them make you a straight test pipe and one with a cat. Then you can just swap it out if and when needed. Now that you have the gms1 you could have some one with HPTuners or Trifecta give you an even better tune, along with turn the code off for the secondary 02. You won't throw a cel from not having a cat then. This is my opinion on the detail but, if you want to get ass plunged on a price then buy hahn products.... the end

 

Buy one used on here. I got my ZZP catless shipped for 150 bucks. I have emission laws here, but I have no problem turning 7 bolts once a year to replace it with my stock catted.

 

It depends on you and what you like, just look at all the DP every company has to offer and make your descision.

I personally look for how the DP is made what the welds look like and i would go with the Stainless steal dont go with aluminized it will rust on you!

 

Thats just a peak number. Where it really helps is in the power curve. Say you are making 360wtq at 3300rpm and by 6300 you are now making 320wtq. The new dp will get rid of that choke point in the higher rpms. So now you might be more like 370wtq at 3300rpm and 340wtq at 6300rpm. Your biggest gain is gonna be getting rid of the stocker. Then the catless just gives that extra bump.

If your worried about the noise, dont be. The only time its loud is that first 45 seconds in the morning with its in warmup mode. After that it only gets loud when your getting on the throttle. Cruising sounds very close to stock.
For the smell. I drive with my windows down 90% of the time. The only time I ever smell the exhaust is if im in a drive thru for a couple mins.

 

Clear Image Automotive Catless downpipe, save your stock one and put it back on come inspection. I have the GMS1 and the Clear Image downpipe and that's it and it pulls way harder than i thought it would. i had a second party drive the car (my girlfriends dad, hes a mechanic into high performance) before and after the GMS1 and the GMS1 w/Downpipe and he said the catless downpipe was way worth the money. it runs great and doesn't throw any codes and under WOT sounds awesome. idles and drives normal pretty quietly. plus a catless downpipe is cheaper.

 

If you go catless dp on gm stage 1, and you throw a code, the only option is to reset and see if it happens again? maybe change the o2 sesnsor? or get it disabled in hpt

 

The only DP I never heard talked about on the forums is the 3" OTTP DP Catless and also their CP's. Has anyone heard any good things about it. I'm been eyeballing the DP and CP for awhile and others like their transmounts.. I plan using it on the roads and switch back to stock on inspection day. Is there any good things about OTTP's product? I know they are praised for the Cobalt SS/SC, but unsure about the SS/TC's.

 

I thought I read some guys using the catless ottp 3" and liked it. It is tempting because after you get it with the angled bung its still $240, which is cheaper than anyone else.

 

I wonder how long it took him to throw a code or CEL.

 

the I think 2-3 ppl that had a ottp catless didnt throw a code....

 

that's awesome. I gotta get one. Don't care about the emissions, until inspection day.

 

I have an OTTP Catless Downpipe and id say it's a good peice but not great. When I bolted the DP in it doesn't sit centered, it's slightly off to the left a bit so it is touching the exhaust heat shield a bit which I had to bend but I'm not very happy with that. I think I will take it to a muffler shop and have them try to bend it a bit so it's closer to center.

That being said the DP has top notch welds and it went in without a hitch, the angled O2 bung is great I havent seen any CEL's and I've had it for about 2000miles *knock-on-wood*. And you really can't beat the price.

 

i want to buy a downpipe as well for my car but i can't post on the for sale forums yet =[
can someone help me out please by postiing for me? i want a cat-less dp!! ty

 

I may be selling mine shortly and going back to stock...PM me if you're still interested.

 

I installed the Hahn 3" dp and cb no codes at all very good fitment and it sounds great .Have had 3-4 good comments on its sound the first came from the owner of the shop that installed it.As for power ,there is definitly a noticable increase and the sound is amazing.At low rpm the sound is a mello growl at high rpm the growl is ,well not so mello lol but not really loud like alot of 3" exhausts.