soo... i want to get some new headers with a bigger output pipe, then prolly go 3" piping to the exhaust. I'm thinking of building the piping myself, i'm wondering if it's cheaper than to just buy a kit. like buy materials, and go to a machine shop to bend the pipes, and have someone water blast the flange, but i can weld it fit it on, etc.

I was wondering though... if the headers for an NA is the same for a turbo II, cause right now the engine is young 47k, and i'm planning on swapping it to a TII, i don't want to buy the headers for this engine, if it wont' fit on the TII one.

and for the headers, if i get a bigger diameter, will that actually slow the output of exhaust? cause instead of that, w/e diameter the stock one is, the molecules of gas would expand more/cool/have a harder time going down the pipe, and travel along a bit slower, and i'm wondering if there would be back pressure if any, to help suck out more exhaust. or is this factor too insignificant? because i don't want it so big that it won't do anything, like trying to push air out of a room by blowing with your mouth so to speak. like what diameter seems optimal for exhaust.

and where can i look to get aftermarket headers. i can't seem to find any.

 

I don't know for sure if the N/A headers work with the TII, but I do know this.... (Not trying to be an a-hole, I just can relate it better in a metaphor...)

Breathe in a big breath and try to force it out of a straw.... hard to do right? Now remove the straw and breathe out, it's alot easier; That's basically what you are doing when you go with a larger diameter exhaust, getting a bigger straw for your engine to breath (out) with. Ideally you could have no pipe and just let the thing belch exhaust all over the place and into your cockpit choking you to death, but that would be bad, and there are other reasons to have a pipe as well, a little back pressure is good I think.... I may regret saying that....


Anyways, I've got a 3" pipe, and my engine loves it, take the smogger off too if you haven't already, that will really help the engine breathe better as well.

 

headers is to NA as downpipe is to........ TURBO.

it wont work. the exhaust from a turbo engine goes to a manifold and into a turbo and into the exhaust. one pipe from the turbo exhaust side.


hopefully i put a little water on the possible flames to come

 

isn't headers the manifold tho? o.0 i mean there are still 2 pipes that go into 1 before turbo right? or different piping. dammit maybe i should just start wiht the engine before i do anything else huh

 

yea, there's no such thing as a header on a turbo.

 

so it's just called piping from the exhaust valves to the turbo?

what does anyone think of a turbo back exhaust at 3"?

i ahve a NA right now, and i kinda wanna do something before i get my TII, casue i only have 47k on it. i was thinking of doing a sigle exhaust 3" from the stock down pipe. think that will cause back pressure? or should it help more? also cause the molecules expand after dp going into a bigger pipe, does it cool it down too much? or would it still be a good operating temp for the cat to filter out nox and w/e?

 

If you want to apply your NA terminology, this picture and what i have circled is the "header" on a turbo II. The correct name is turbo exhaust manifold, and as you can see, totally different than a NA header.

 

For now If i was you, just buy a cat back, if you're planning on buying a turbo, you can use it on both cars.

 

In order of flow on a turbo car: exaust port(no valves), exaust manifold, turbo, downpipe, midpipe/cat, catback.

In order of flow on an NA car: exaust port, stock exaust mani/headers, midpipe/cat, catback.

That will come with a downpipe that will bolt to a turbo. I would go with a Racing Beat header to a RB presilencer/custom made midpipe/cat/whatever, and a catback. When you go turbo, the catback will transfer over, and possibly the presilencer/midpipe depending on what you choose.

Keep in mind that a freely flowing exaust on an NA car is LOUD.

 

sweeeeeeet thanks. any problems with increase in diameter from the downpipe to the 3" piping? not much affect? whats the range on hp with this anyway? like 2-5hp gain or something? also i'm thinkin of just buying a cat and exhaust with 3" intake an outake (for cat anyway) and go from downpipe (stock) to 3" to the end.

 

also thanks for clarifying all the parts for me haha. oh is the turbo exhaust mani the stock one in that pic?

 

stock s5

 

ohhh kk. and what does fsm stand for... is that the faq here?

 

FSM = Factory Service Manual. Found linked in the FAQ.

 

cool thanks. oh also i have a question. i was talking with one of my buddies that i work with here. and he was talking about exhaust, and how scavaging works. for rotaries do we even ahve to worry about scavenging? or not at all since we have no ports, and the rotar kind of pushes everything out?

 

yes it helps on rotaries also. although i believe turbo systems dont benefit from it though.

 

you can hop on ebay and buy a pacesetter header and ssautochrome turbo back exhaust. the catback and midpipe will bolt right up to the header. when you go turbo you can sell your header and you'll already have your 3" downpipe.

 

oohhhh sweeet idea. thx guys