Anyone running a downpipe?

[ptgtcb]

MexicanPT, I am very glad to hear your system is not reeling it's self back in.[:X]

I feel if we open up the CAT and down pipe to 3" we really do not need a 2.5" all the way back and that the stock exhaust will work with a straight through style muffler. We are removing a lot of the restriction in the exhaust with the downpipe, negating the requirement for the 2.5" exhaust for stage II. The Stage II requirement for 2.5" is only CAT back and retaining the stock CAT!

Remember, you also want to keep the heat in the exhaust because hot gases will flow faster, 3Bar is seeing an improvement with only a 2.25 test pipe! Is he still running a stock exhaust to the back?

Is opening up the o2 housing really going to make that much of a difference? It is only about 4" long and the turbo opening it's self is only 2"?
However, there are several companies making 02 housings that should work with any down pipe and ATP is considering an 02 housing. We should lobby them to make the downpipe fit directly to the stock PT exhaust.
Contact them @ http://www.atpturbo.com/root/navigation/contactus.php

Just my thoughts

[LAF]

MEXICANPT,

I am waiting for it(ATP down w cat)to come in the mail and want to be sure of everything here.

Did the O2 sensor go back in ok on your ATP? By this I mean I see the O2 is behind the cat on the transition pipe to exhaust. I assume so you can pull the cat, 2 bolts with the V-clamp, put in a race pipe, go to the track, and not throw a code, cause your O2 sensor is still there Was there enough wire for it to reconnect properly? Was any wire splicing needed there? I just want to be sure before I go to the shop for the pipe!

Also, as I am doing the same thing with the pipe to the BTG axel over, how do you like it sound wise?

[MEXICANPT]

The O2 sensor fits just fine, but whenever you remove the cat a CEL will come on, the PCM compares the air between the upstream and downstream sensor and if the readings are the same the CEL will come on to let oyu know your cat has deteriorated.

I'm not sure about the wire splicing since I wasn't actually there when the installation was being done, but I assume there was none of that.

I love the way it sounds, with my BTG CAI it's louder than a SRT-4, I tried it wothout the CAI and it's just like a SRT-4. I like it loud but not to the point where you can't speak in the cockpit.

You'll love it, trust me.

[LAF]

Had my 3" down with cat on today. All I can say is 1st gear don't last long, and I think I can hit the speed limiter in 3rd with auto stick, and not hit the rpm shift point. Top end just spools so nice. It was pricey, but when you see firsthand what comes off, and what is on, you would say it is the foundation of a great exhaust. I have some picks and if you want to see em I will post, I was under the car on the lift shooting them while the Monroe guy was working. He was cool.

Mexicanpt you were right for sure, good call.

[ptgtcb]

[:X]

Please post some pic's when you have a chance . This mod is going to work great with SII. This is killing me I've got to order this soon [8)]

[crazyjoe]

quote:Originally posted by ptgtcb

MexicanPT, I am very glad to hear your system is not reeling it's self back in.[:X]

I feel if we open up the CAT and down pipe to 3" we really do not need a 2.5" all the way back and that the stock exhaust will work with a straight through style muffler. We are removing a lot of the restriction in the exhaust with the downpipe, negating the requirement for the 2.5" exhaust for stage II. The Stage II requirement for 2.5" is only CAT back and retaining the stock CAT!

Conventional wisdom on exhausts is that you do not want to shrink down as you go along the pipe. As the air cools, if you restrict it more, it will have a bigger impact. No turbo guy I know will suggest going smaller as you head toward the bumper, so I wouldn't recommend it. If you DO do it, let us know how it works, though.

[LAF]

I did it, and don't see an issue. While it is true that it gets necked toward the tail, really axle/octy over to BTG Strait thru muffler. I Believe 3bar said these things don't like back pressure what so ever ESPECIALLY next to the turbo. Well, when you see this ATP pipe and your own stock cat, you know you did the right thing. OK, then I put on a true 2.5" pipe to the axle over with BTG. What did I do wrong? I just replaced the exhaust from front to rear that FAR exceeds factory, Mopar, or any other exhaust on the market that I haver seen. Yes I know the axle over is a block, it needs to go for sure, just trying to figure out how. Then a 3" pipe all the way with resonators and chrome tip. Till then I don't think my turbo is going to do anything but flow, long and strong. Oh, and I bet you my gas mileage goes up.

[ptgtcb]

quote:Originally posted by crazyjoe

Conventional wisdom on exhausts is that you do not want to shrink down as you go along the pipe. As the air cools, if you restrict it more, it will have a bigger impact. No turbo guy I know will suggest going smaller as you head toward the bumper, so I wouldn't recommend it. If you DO do it, let us know how it works, though.

Did you even read my post?
Actually with the smaller pipe you are keeping in the heat in the pipe and the gasses are flowing faster. Larger the pipe the sooner the gases cool and slow. My exhaust is also a straight through muffler. The stock cat is choking the heck out of the engine. I think you are going to reduce a lot more back pressure with the CAT/downpipe than with a CAT back exhaust system. BTG got very minimal, if any, gains with a 2.5" over their 2.25 system so I think that should tell you something. LAF said it best, this is a good foundation to an excellent exhaust system.

[LAF]

OK had the ATP 3"down pipe with cat installed for a few days now and have some time to run and adjust it a bit.

On the adjust part I had a hit from a bad bend around the gas tank heat shield, had a new stick re bent this morning and that issue is solved. While looking at it I realized that the flex down pipe has a lot of slop in it, it is like 8" long at least, so I asked my Monroe buddy to weld me a small stay from the new lower section of the ATP, in front of the O2 bung, to my frame. That did it very nicely. As it was, it just hung from the flex down pipe all the way to the first rubber grommet at the front of the rear wheel, too far in my opinion.
Still have a slight rattle where I need to loosen up the v-clamps and turn the cat a hair to get it centered in the channel a little better. Price one pays for custom work though and I am getting it worked out.

Power and spool are just too much. It works well and is all I will do for my exhaust. I just wanted all to know my experience with this install, it wasnt bad at all. Worth the money for sure, and I would say if you are going to Stage II, do this mod. If not, still do it.