Well the flex section in my wife's 225 tt broke.

I'm trying to decide what to buy. I've searched this site and others to get input/advise but I still have some questions.

There is a lot of info on the 42DD downpipe. What I don't like about it is that it is aluminized steel. I live in PA that uses plenty of salt and even when aluminized pipe came out years ago the exhaust still would go bad just took about a year longer. Also, they seem to hang low which I don't want.

The Relentless is stainless and has some positive reviews and the newer versions don't seem like they have the fitment issues the first ones had. But, people say they are thin and a knock off of the 42DD. Cheap but how long will it last? I don't want to do this twice.

The cheapest I found the stock DP was 400 plus shipping. Just don't want to drop the subframe to refit. Also, the car has the 265HP APR remap so If a 3" DP will make more power that is always a plus.

Any others out there that I need to look into?

Those that have any of these how are they holding up?

Should I get the pipes with the cat delete? I don't have emissions checks in my county so I could run straight pipes if I want.
Can the O2 extensions stop the CEL? or does that need to be programmed out?

I know a full exhaust will be the best powerwise but I have no desire to spend that amount of money. I'd like to get this taken care of for less then $500. This is a woman's car and she doesn't want anything that is loud.

 

I installed a Relentless on my APR chipped 225 a couple of years ago. The install did require some modification of the pipe behind the Cat because it did not match up with the exhaust. My car already had a Borla Cat back exhaust installed. The fitment past the drive shaft in the tunnel under the firewall is REALLY tight. It takes some finesse to get it to work without bumping. I installed a stiffer dogbone (pendulum mount) while there to help with interference. I used a spacer on the rear O2 and got the CEL to clear ok. (Relentless does have a high flow cat) All in all it has been ok, but lots more trouble than I had hoped. The car sounds better with less drone at 3000 rpm. The power increase is nothing to write home about. I'm not sure it is measurable. I do track events and my speeds at end of straights at Road Atlanta, VIR, Barber ect did not change appreciably. I'm not sure they did at all. I really cannot advise you what to do but I would at least look for a good OEM unit from a salvage company.

 

Another option is to have a new flex section installed on your old pipe. Assuming it is still solid.

 

So your saying that the DP made absolutely no difference in the performance. That is good to know. I figured if I have to change mine out I may as well try to improve my power output.

I can't tell if you have the cat or catless, you said Relentless has a high flow cat but is that the one you have?

Thank You, these are the facts that I need to know.

 

I also though about this. I've found some flex sections online. My usual exhaust guy says that the new flex won't last and he won't change it. He says some cars aren't worth his time. He won't touch the dp on my TT. He wants to do easy jobs to make more profit, I guess I can't blame him.

The main reason I was going aftermarket was the fact that I could hack my DP out and not drop the subframe to replace it. Trying to make it easier on myself since I'll be doing the work.

Anyone with flex replacement experience? Work for a long time or not? It will be Mig welded not Tig, since that is what I own..

Thanks

 

Yes-- My Relentless has the high flow cat. That has never been a problem. It does take a bit longer for readiness to set on the rear O2 sensor but it does set. (with a 90 degree spacer) I realize my observations of little power gain if any are against the claims of most but I have data from two different trips to VIR both with the downpipe and without. Speeds at the end of the long straights were nearly identical. (125mph + - 1 or 2.)

 

I replaced the dp on my 2001 TT 180 with an OEM one because it blew a hole and sounded like a truck... no time to investigate options. This time, I have upgraded to a 2005 TT 225 and at 200+ kms decided to change it before the same thing happened. I have changed it with a CTS Turbo 3 inch 304ss dp and also replaced the rest of the exhaust with the CTS Turbo cat back system. I am so happy I did this. It sounds great and has more horses to play with. Gumper

 

I have a relentless dP on my tt for the past 3 years. Mina was the eArly version, so I did have to grind the flange slightly. to clear the manifold stud. The finish is great. The cat converter sat to low to the ground. Relentless did not do anything for me about the cat section sitting to low. I had a custom hi flow cat and pipe fabricated to fit properly. I did have to upgrade my dog bone mount and engine and transmission mount. The downpipe was a times touching my sway bar with my worn mounts. Since then, it's ok. No body vibrations. For the cost of my stainless downpipe and a new cat fabricated, this was still more cost effective than a cts or 42dd unit. Relentless intercoolers for the Audi TT 225 have intercooler pipes that will not clear the stock bumper ends, unless you seriously cut apart your bumper. I wound up returning mine, with problem from the vendor and bought a 42dd intercooler kit and could be more satisfied. One word of advice, pay with PayPal when dealing with relentless. Just in case you need to return or exchange anything from them.

 

42DD here and 30K on it and it still looks like new. I have one of the earlier ones that is Stainless, you can still do Stainless for a little more. No fitment issues which is a definite plus.

 

i have the relentless 3" catted setup + their uncatted pipe for off road + the borla 2.5" cat back fit was decent for the $$$. 300 series stainless is smart unless you live in arizona!!! my roadster is a summer fun car mostly but ready whenever needed in Pa weather. labor alone can be costly unless you have a FWD car. i had the borla cat-back on shortly after i got the car several years ago, wanted a downpipe but most were $$$$ + stainless was my requirement. after adding the relentless catted 3" setup i could feel the difference + see the quicker reacting boost gauge, even more so uncatted!!! my system is decently quiet with little if any droaning that many full 3" systems have i put the medium stiff dog-bone mounts on + a little tweaking + no rattles. i have 215-50-17 tyres on new suspension 25mm lowered which is the same as my tired OE ride height. just checked 42DD they have a 304 stainless catted setup for $835 for a 225Q a decent price for quality + good fitment, + its a 2 pc setup that installs easier + allows easy bolting on the uncatted-race section. they only had aluminized steel years ago at almost the same cost + from experience it don't last in Pa