Very long story short, I have 3 gauges..I'm not attempting the install. 2 shops quoted me at $350 - 460.

Now.. if they have to take off the stock downpipe to weld on a bung for the AFR gauge then they want $460 total ($135 for removing and installing downpipe). Do I pay that price or just buy a downpipe (aiming for AMS) with a bung already on it?

Many sources say downpipe doesn't improve anything and it's a waste of money if I am not planning on changing the turbo. So Idk what to do.

I figured since they are removing my downpipe to install a bung on the stock pipe (assuming the stock downpipe doesn't have one?) They could just install a new downpipe.. but why pay more money for a down pipe if it is not necessary...... basically $135 extra to install rather than the $400 for a downpipe.

Advice please. Sorry for the sloppy English.. I'm typing on my phone at work lol.

 

there are 2 types of 'downpipes', first is the one with the o2 housing, the other is just the elbow pipe that connects to the o2 housing.
when u said ams, theirs is attached to the o2 housing (bellmouth in their case)

if you are going with the elbow part, i read that ams posted and showed zero gain, it is only when you change the o2 housing as well that there are gains. but more people said if you have stock turbo to pass on it and use money elsewhere.

if your just thinking of doing it for the purpose of a gauge i would just change the elbow or see below.
also, might ask now, do u have stock cat? or hfc or are u considering changing it? because they do have bungs welded on some of them already and you can just change that piece out and put the wideband sensor in there. get my drift?

in my case, i didnt want to pay for that downpipe for not much gains, plus the install price. so i opted for an ams hfc and it has an extra bung on it so i can put a wideband sensor in.

 

OP, Thanks for your question! I'm going through this dilemma at the moment.



SujinX, you're correct! Having the AFR attached to the HFC or TP is another option BUT, some have said that having the AFR connected to the HFC or TP wont be as accurate as if it were connected to the DP. Could this be true and does it really matter?

 

The difference in accuracy between the test pipe bung and downpipe bung is negligible. Unless you're planning to get a bigger stock frame turbo in the future, you're better off just putting the sensor in the test pipe/HFC.

 

Waste of money on stock turbo. 5, maybe 10whp is not worth the 500 dollars, plus install, plus very possible headaches of breaking bolts off in the turbine housing. If you ever do an upgraded stock frame turbo later on, install a downpipe and manifold along with it. The shop also should not be removing the O2 housing to put in an O2 sensor bung. They're likely removing the short pipe between the O2 housing and the cat.

 

i would like to know who said this, because the bung on the elbow vs the bung on my ams hfc (which is still before the cat) is no more than 5" apart and if 5" length is not accurate on a car i dont know what to say.
below is the ams hfc, the bung on the right is the one im talking about, the left is the secondary.


here is the ams downpipe with bung and the bung on the hfc for visual purposes, photos via google.

 

Sometimes Maperformance puts their downpipe on sale. I bought mine for 3.. something. I would suggest waiting for a sale and replace the downpipe !

1whp is 1whp !

 

1whp that costs $XXX install plus a re-tune? That's just a waste of people's time and money.

 

This is all I needed to know! Thanks guys! Looks like I'm going to pay the additional $135 (instead of $500 for new pipe) for them to weld one on my existing down pipe.

I have the ETS V2 exhaust. I am not planning on changing any turbos or anything. Just need a simple gauge put on then jumping on the dyno. I don't need to waste $500 + labor for 1whp gain. I am not sure if I already hang a bung or not on the stock pipes. I believe not.

thank you for the help.

 

It was brought to my attention I should just get a test pipe with a bung to finish off my bolt on... but I am not too sure the difference in test pipe and down pipes or what's better..

 

Bung-wise for a wideband AFR gauge, the downpipe location will have slightly more accurate readings. However for a DD bolt-on car, either location will work.


Lots of test pipes come with an extra bung already on it, so that's very much OK to use instead of having a new one welded on your downpipe for extra expense.

 

^ local people are selling AMS test pipes for $140 and to weld one on my stock pipe is $135. I have the ETS V2 exhaust... will the test pipe amplify the noise level times two? Are all test pipes compatible with the V2 system?

 

A test pipe and a downpipe are different.

The test pipe replaces the cat with a straight through pipe. The test pipe connects the cat back to the downpipe.

There are downpipes that include the "test pipe" section making them go from the turbo all the way to the catback. There are also downpipes which are only the downpipe section. This then requires you to get a test pipe or a high flow cat pipe to go from the downpipe to the cat back.



As of right now I'm only running an aftermarket catback, but I like the idea of having the test pipe separate from the downpipe. This allows you to quickly throw the cat back on if you need it for an inspection. Although I'm not sure how often you would ever have to do this...

Also, it seems like with the X, an aftermarket downpipe does not offer much HP so you should probably just replace the cat with a test pipe or a HFC and forget about the downpipe for now.

 

^ you're the man. Thanks for the explanation.

 

Kreeker gave some good advice.


Regarding the noise/fitment - yes, it will be louder. Yes, any test pipe by any of the reputable names will fit with the V2 system.


Note if you get a test pipe, you need to get a tune for it (if that wasn't in your plans already).