Hey guys, I needed some info before I buy the ATLP exhaust. I'm currently planning:

Comptech Headers>XLR8 Cat>ATLP

I believe everything is bolt on except for the connection between the Cat and the ATLP straight pipe, which is welded. My question is, what is the stock cat outlet size? I know the XLR8 outlet and the ATLP inlet is 2.5", but will the stock cat be able to connect to the ATLP? I ask this because I don't want to have to bend the ATLP pipe to make it fit, as I can just wait until I get the high flow cat.

I have a TL-P if that affects the cat outlet diameter.

 

being that you want to do a full exhaust with HEADERS, it does not really matter if you got a TL-P or an S (but yes the S has a slightly larger diameter exhaust though, and a different bolt pattern, but that should not matter though)

as far as everything bolting up, should be no problem since everything is design to work with stock compenets still in place (you just happen to be replacing them with other components that are designed to be a direct replacement





biggest i have had with the mix match of exhaust components though, has been getting a good seal between the components with gaskets and such though (but nothing that a little permatex muffler and tailpipe sealer can't fix )






btw i hope you are prepared for a louder exhaust with some good drone to it

 

I don't mind it being loud, but I'm trying to avoid drone/rasp. A little drone is fine, but I definitely will change something if it's raspy.

So I can have the ATLP welded onto the stock Cat, and then change it to the XLR8 Cat later?

 

No welding should be required at all. It is straight bolt on from headers -> cat -> exhaust. The catalytic converters itself are welded onto straight pipes, which connect to the headers/exhaust. So you can just swap in the HFC later. Being that ATLP exhaust and XLR8 cat are both compatible with the TL-P, it shouldn't be a problem for you at all.

 

Oh ok, that's awesome! I didn't know that the ATLP exhaust had the bolt on part at the inlet.

Thanks for the info!

 

and as said biggest issue is getting a good seal between those flanges (because they are only worried about matching the stock components nothing aftermarket)






and as far as how much drone ask kdawg, he has the ATLP with comptech headers (and i had sold him my high flow cat) and when he put that on the drone was too much for him, so he had to put the stock cat back on






and personally people hate raspiness, i actually like it having some on mine though (comptech headers, p2r straight pipe and apexi exhaust), and it is still a relatively quite combo too (so drone is minimal)

 

That's an interesting setup. So the p2r straight pipe is replacing the cat?

Would you say that the CT headers + ATLP exhaust is the best setup for performance? I might stick to stock cat if the noise is overwhelming.

Btw, I'll PM you when you need to change your sig.

 

best performance would be without the stock (even if it is a high-flow replacement)


for5 a direct bolt-on application yes i would say the comptech headers, either a test-pipe (or at a minumum a high-flow cat), then the ATLP would be the best for performance, but you have to be able to withstand the extra noise though


but if you are willing to go a custom exhaust route though (which i want to go, my apexi came on the car ), i would say you be able to achieve the same power, while still having it be a bit quieter at the same time too (since iirc the ATLP was made not only for power, but also those people who do like loud exhausts, so it has very little sound dampening in the system

and the comptech headers they are considered the best especially for build quality, but they could be slightly larger at times though, especially in the j-pipe section (it's only a 2" outlet ; which for a relatively stock motor is fine, and does not sacrifice too much low end, but once the engine really starts to be upped in power; ie force induction, nitrous, stroker; they do start to become the limiting factor)







and as far as my sig, you are in the SOUTHWEST, not the Rocky Mountain region








edit: and yes the p2r replaced the cat (so i have no cat on the car)

 

use a good hi flow cat from Excelerate/Josh
ck the info on using a spark plug anti fouler on the O2 sensor here on azine, or the tube for O2 on cat being extended approx 6 inches to get useable reading for the ecu

that will keep the car running pretty low emissions-
do something to offset your increased carbon footprint from more throttle use and more time just fun driving on the backroads,,use of SS - higher rpms,,,all at 4 bucks a gal already!! here in Ca. and expected to easily reach 5 by summer

 

spark plug anti-fouler don't know what you are smoking..., but i want some

but yes a anti-fouler will still be required with the hi-flow cat from josh (had to use one on mine when i had it to keep the check engine light off; it keep itself off for about two months, then it popped on after the cat was "broken" in)


as far as low emissions, i guess but i will say though that it did keep the smell of burned fuel and such down though (to the point where it still smelled like a stock cat when it was running) since some people do not the smell of the raw exhaust (btw: if you ever smell race fuel )



edit: btw the only hi-flow that i know of that is a direct bolt-on is from josh (actually random technologies makes it for him), so not much as far as choices out there