Makaan

I have a 2006 Tc and am just now getting into tuning and customizing it to my liking. I was wondering if anyone could shed some light on whether or not getting a Down Pipe for your Tc will limit your choices in Cat-Back Exhaust Systems? Also, does the Down Pipe actually replace the Catalytic Converter or does that have to be moved somewhere further down the line of the exhaust line?

Thanks, and hope to see some response!

Mid_Life_tC-risis

You can connect any exhaust to any aftermarket downpipe, or S-pipe. The s-pipe does not have a cat, it's just the pipe that connects the exhaust manifold, which contains the first cat, to the midpipe, which contains the second cat.

But a new s-pipe, which typically runs $150-200, is a waste of money. You will see little or no HP gain from a new s-pipe.

If you're not getting a header, you've maximized your exhaust gains after replacing the stock midpipe + axleback muffler.

SPscionTC

Only thing to look out for is the piping size! if not there will be leaks through out your exhaust, and that will suck!
It's better to double check before than to not be sure what to check for after.

Mid_Life_tC-risis

All the aftermarket "s-pipe back" (catback) exhausts and midpipes are designed to bolt on properly with the stock s-pipe.

But you don't have to buy shiny aftermarket exhausts. Another option, which will save you hundreds of dollars, is to have a local exhaust shop make you a "custom" exhaust. After all a catback exhaust = pipe + muffler(s) +flanges +gaskets + hangers. Nothing complicated ...

Sleep3r

Makaan get what you wanna get do a little search BTW you have the best avatar!

NurSpec

A downpipe is generally a term used for the exhaust pipe turning downward from the turbo charger's turbine side.

Mugetsu

Old Muscle car heads call what we call a "S-pipe" a "Down-pipe" the term wasn't born from rice...err turbo

Menace

I got one for sale if anyone want Brand New.
Oh and don't listen to midlife_crisis, it adds 15hp

SoccerBoy_AP

Invidia's downpipe does give a considerable boost in power for a simple bolt on. The piping thru that section of the exhaust system is smaller with the stock pipe, upping to the Invidia pipe will increase airflow and even more so if you throw in a new header with it. Our full exhaust system changes pipe size throughout, thus bottlenecks.

Correct me if I'm wrong...

Menace

The s-pipe is widely considered to be the most restrictive part of the exhaust. Not only due to its sharp bends but also because of the narrow opening where it joins the mid-pipe. I have not put mine on because I am getting the Weapon-R header but I bought it because I strongly believe in it. There is a lot to be gained if you upgrade your mid-pipe, take off the cat, add a better flowing muffler, and yet bottlenecking at the s-pipe imo. While it will not add crazy hp, you can expect some more pull in the upper ranges.

Mid_Life_tC-risis

Thought you were joking until I read your second post.

"The s-pipe is widely considered to be the most restrictive part of the exhaust."

Let's see, in the stock exhaust you've got:
(1). a baffled/chambered muffler with no direct path from inlet to outlet
(2). cat in midpipe with closely-spaced honeycomb internal
(3). the s-pipe - yes it's got funky bends and reduces to 2" id - but is still just an open pipe

Yeah it's gotta be (3).

Menace

LOL I was joking in the first post. The second post is correct though. I knew you were going to call me out on it. Lets take a look here. When you replace the chambered muffler, with lets say an hks or evo2 axle back, do you get more than 1-2, maybe 3hp if you are lucky? The answer is no. The mid-pipe, with the cat in mind is actually the least restrictive, especially in an N/A application. There are a few people that replaced everything else and did the mid-pipe last, they noticed almost no gain. It is pretty straight through and adequate on it's own. If one were to go F/I, especially turbo, then it would make a world of difference. We can argue the difference of opinion but there are more poeple in this forum that would agree with mine than yours. Have you read some of the s-pipe owners comments after acquiring an s-pipe, there is nothing but positivity in those threads from it's effect. You can try to attribute that to the placebo effect in your next post but I still say if you keep your expectations reasonable it is definitely worth the upgrade. Why would one even bother to upgrade their exhaust if they are bottlenecking at 2" with the stock s-pipe.

Mid_Life_tC-risis

Agreed on that. However replacing the midpipe with a catless midpipe, or replacing the midpipe cat with a high-flow cat such as a Vibrant metal-core high-flow cat, are IMO money better spent than on an aftermarket s-pipe (although NONE of these 3 options is money WELL spent ).

click for Vibrant cat

The sad thing is you are probably right about people's opinions on SL about the s-pipe. I too have seen all the glowing comments about this magical piece of empty pipe. The car sounds different because you've changed exhaust characteristics slightly. So folks post up "Felt better pull!" ... "Car sounds faster!" ... "Everybody should get one!" How this came to be is an example of aftermarket hype overcoming common sense. So let me ask you this ...

Have ANY of these "S-pipe is the $hit!" testimonials ever included a dyno result? Improved 0-60 times? Better 1/4-mile?

NO, because on an N/A tC an s-pipe might gain the equivalent of a dyno error, and the aftermarket companies know this. If someone would actually do an "S-pipe Shootout" it would kill all the senseless hype the same way the GSC Intake Test proved those K&N drop-in "high performance" air filters gain NOTHING.

Sleep3r

just let people get what they wanna get and go by whatever people say / experience, thats what modding is all about. if you feed everyone with your negative knowledge about don't do this and spend money on that then your just asking for an argument.......seems like everyone wants to have the LAST WORD.....

Menace

Midlife I understand everything you say and agree with most of it, however, everything you say applies to practically everything except F/I. I am just wondering why you are so adamant about the s-pipe in particular when the same case can me made about any part of the exhaust except maybe the headers, and thats a whole another issue on their own. My point is that if you upgrade your exhaust system, there is no reason not to upgrade the s-pipe, its an integral part of your exhaust. As long as everyone has reasonable expectations it is more than justified imo.

Mid_Life_tC-risis

IMO the s-pipe is wrongly characterized as a performance part for the N/A tC. As you've pointed out most people seem to have "drank the kool-aid" on this pipe, for unknown reasons. I've seen it touted for everything from "significant HP gains" (without a dyno or time slip to prove it) to "I'm buying an s-pipe to fix my rasp".

In fact, there is no evidence that it will increase HP or improve track times, and there are people saying their new s-pipe actually caused rasp.

For people conscious of $$ per HP, for a s-pipe/catback exhaust - which is the topic of this thread - for N/A the only exhaust part worth replacing is the stock muffler. This has been shown to provide a gain of 5-6whp on a stock manual tC.

https://www.scionlife.com/forums/viewtopic.php?t=80070

A suitable aftermarket muffler can be bought and installed by an exhaust shop for less than $125, giving a $$/HP ratio of $25 or less. This is good bang-for-the-buck compared to an s-pipe retailing for $150-200 which might give 1-2HP at most.

Menace

I tend to disagree on the notion that since it hasn't been tested it is an inferior upgrade. Lets be realistic, GSM motorsports did a good job of testing products that they carry. Thats it. No one else has done any other type of independent testing nor was the Invidia s-pipe available at the time of testing. Also, why wouldn't it be characterized as a performance mod? In every other car a more efficient flowing downpipe is characterized as a performance mod (not to mention most of the other stock downpipes are straiter and more consistent in diameter as opposed ours).

As far as causing rasp, that it will, anytime you increase flow, in turn you increase rasp. This is also exaggerated in DOHC engines.

Last, its not just a muffler that gave 5hp gains in those tests. It was an axle-back. Replacing just the muffler will not produce as much.

Mugetsu

On our car the "muffler" is an ""axleback" its one piece simple as that.

I have never heard an S-pipe causing nor curing rasp...
*edit: rasp is not caused by increased flow, its caused by poorly tuned after market headers( as in all them) But the stock one is no better( as some would like to believe) its the combination of both cats + the stock 18" resonator and the chambered muffler that makes a stock tc so "raspless" and quiet.

I also think on an NA tc a megan 2.25 s-pipe is enough and a 2.5 one will only result in loss of low end TQ.

If i could only change out 2 parts of my stock exhaust i would choose the header and the axleback muffler.
the rest is just open pipe of slightly varying sizes(minus the cats course). the stock s-pipe IS ugly but not useless.

Sleep3r

^^ as far as the megan 2.25 goes......it also results in loss of low end TQ, i had it then went back to OEM

Mid_Life_tC-risis

GSC tested almost all products available at the time in 2005, not just ones they sold. For example they dyno'd Weapon-R and Unmitza intakes that were sent to them by their mfr's.

I'm not saying the s-pipe is an inferior upgrade just because it hasn't been tested, I'm saying no one is going to waste their time on a dyno of a section of open pipe hooked up to a n/a Camry 4-banger. Least of all the aftermarket companies who sell these s-pipes, because the dismal results would hurt their sales.

You're correct in saying smoother, straighter, constant diameter piping makes good flow and a technically better exhaust. But the results of replacing stock piping don't show up - and therefore IMO are not worth the cost - until you connect them to a much more powerful engine. Which for the tC means forced induction.