Anyone running a downpipe?

[MEXICANPT]

Finally my mechanics got around to installing my downpipe.

I dropped part of my BTG cat-back along the way, they installed the downpipe, then they removed the bottleneck of it, they ran a 3" tubing all the way to he axle-back of the BTG.

I haven't had a chance to test it properly, but the sound it just like that of an SRT-4.

I'll be updating this tomorrow.

[ptgtcb]

Hello MEXICANPT, [:X]

Are you only noticing an improvement above 4000 RPM? Does it pull hard(er) all the way to redline or does power drop off? Any check engine light? Could you describe the improvement in more detail, please. How is the quality of the downpipe? I want to install the same downpipe and need convincing.[]
Thanks

[MEXICANPT]

Hi ptgtcb

The quality is great, it loks much better than the OEM part.

The fit is perfect on top, you just have to lenghten it a bit to meet the exhaust, something I didn't worry about since I ran a 3" tube from it.

I drove the car some more today and let me tell you this, it's stonger to below 4000 RPM, it just gets off the line quicker and the revs climb like crazy, I'm taking it to the 1/4 mile on sunday to measure the difference in perfomance.

I'll keep you posted, but I just have to say this, this piece is by far a better mod than any CAI or catback, I have both and it's only behind my Stage I when it comes to seat of the pants performace.

I'll keep you updated.

[jgale]

From what i've been told, this is precisely why the Mopar exhaust is 2.5". It would be very interesting to see a dyno plot of a stage 1 GT with a 3" turbo-back set-up vs. a 2.5" turbo-back; if only to see where the torque peak moves.

[Rolo]

Hmmm...from the Service Manual, p. 14-41, 42:


UPSTREAM OXYGEN SENSOR
The input from the upstream heated oxygen sensor
tells the PCM the oxygen content of the exhaust gas.
Based on this input, the PCM fine tunes the air-fuel
ratio by adjusting injector pulse width.

The sensor input switches from 0 to 1 volt, depending
upon the oxygen content of the exhaust gas in
the exhaust manifold (this is offset by 2.5 voltage on
NGC vehicles). When a large amount of oxygen is
present (caused by a lean air-fuel mixture), the sensor
produces voltage as low as 0.1 volt. When there is
a lesser amount of oxygen present (rich air-fuel mixture)
the sensor produces a voltage as high as 1.0
volt. By monitoring the oxygen content and converting
it to electrical voltage, the sensor acts as a rich-lean
switch.

DOWNSTREAM OXYGEN SENSOR
The downstream heated oxygen sensor input is
used to detect catalytic convertor deterioration. As
the convertor deteriorates, the input from the downstream
sensor begins to match the upstream sensor
input except for a slight time delay. By comparing
the downstream heated oxygen sensor input to the
input from the upstream sensor, the PCM calculates
catalytic convertor efficiency. Also used to establish
the upstream O2 goal voltage (switching point).


So...will horking these two inputs confuse the PCM and mess up the injector pulse widths?


Deleting the cat: O2 sensor outputs match, thinks A/F is rich, thinks cat is dead, triggers CEL

Deleting the cat, let downstream O2 sensor dangle: thinks A/F is terribly lean, dumps fuel to match, ???

[brngrhd]

no it will not dump fuel. it see's upstream as ruler if it says it's good then it will ignore the downstream it will set 2/2 o2 stays lean. they set codes for rich and center too. as far as i know i could be wrong since i have not seen this done.

[ptgtcb]

It would seem to me the o2 sensor is going to see quite a bit of o2 dangling around and will never come to temp most likely burning out he heater, both of which will set a code asap.

[ptgtcb]

quote:Originally posted by MEXICANPT

Hi ptgtcb

I'll keep you posted, but I just have to say this, this piece is by far a better mod than any CAI or catback, I have both and it's only behind my Stage I when it comes to seat of the pants performace.

I'll keep you updated.

How is the Downpipe working now that you have some miles on it. Do you think the PCM is reeling in the power improvement?
Thanks

[MEXICANPT]

Nope, it still feels just as strong.

There's a speed bump in the street I live in and if I mash the gas pedal now I get to the first turn's "braking zone" about 9 MPH faster than before and the distance is about a 1/4 mile.

It accelerates harder, but the real difference is in the upper end of the tach, above 80 MPH it just accelerates much faster than before.

I strongly recommend this mod.

[LAF]

OK I am convinced!!!!!!!!!

I ordered the ATP 3" with H/F Cat. I have looked at all offerings that have been shown in various links. There just does not seem to be anything close in quality. I mean no disrespect to anyone. And yes it is more than others offered but again, look at it.

Just look at this thing on their site and you tell me.

http://www.atpturbo.com/Merchant2/me...gory_Code=VSRT


I got a quote in writing for 70 for the cat to the BTG axel back in 2.5" Also will install the down pipe and cat for 30 at a local Monroe.

I know every one is saying 3" to 2.5" what is the sense, blah, blah. Well first I think the opening of 3" will decrease back pressure, yes I know there is an O2 pipe there also, but I think this is going to take a lot more stress off of the turbo and increase exhaust flow a LOT! And yes to a BTG axel over, blah, blah. Well at least it is high flow.

So 364 to my door in pa, 100 for install and 2.5" pipe, and what ever I have in the BTG axel back, I think 200 or so. So for 700 I got the highest flow solution other than resonators, but will still have that choice and sell the BTG.

BTW, when they had it on the rack to quote it I just could not believe how small the stock exhaust pipe is. What is it, 2" or 2.25”?

Mexican, you got me convinced, I was on the edge, and you pushed me over.