Just got a TopSpeed header in the mail and a Vibrant 2x6 flexpipe.

I am going to chop the 'stock' TopSpeed flexpipe out and replace it, I just wanted to know if I should add any length in the process or if the fitment should be good already?

I know others have talked about adding a little length to the DC header and I figured since this was a copy of the DC header that this may benefit from a little extra length.

Just wanted to check and see before I dig in on this.

Thanks.

 

I got my header installed first and then had the flex pipe replaced. That made work more precise and lowered the chance of a failure of length.

 

^+1

 

Ok, so since it seems I just need to fit it and see for myself if I need to leave some length, I'll retire that question

How about a question about the header itself. It seems the stock bottom section of pipe (on my 06) that attaches from to the upper section of the stock exhaust manifold to the cat is larger in diameter than the topspeed header's bottom section? Why would that be?

 

Down section is indeed larger, but the pipes that lead exhaust away from the cylinders are narrower. The purpose of that is suppression of sound. That wide pipe works like a muffler between the small chamber where individual pipes merge and restrictive catalytic conv. Makes sense ?

 

Yep, that makes sense. I haven't got the stock exhaust manifold off yet to take an inside gander at that lower section. Dang lower section flange to cat flange bolts are not wanting to come loose without stripping the nuts so i figured I would get some replacement bolts and nuts before i go any further.

 

^ wd 40 ?

 

Yea, wd-40... I used an open ended wrench and rounded off the head of one of the nuts, decided i'd wait to get replacement studs and nuts before I go any further since I dont want to reinstall with bad hardware. Autozone wasnt able to tell me what exact bolts and nuts I needed so I am working on figuring that out right now. Might just have to get one off and take it to match it up at a hardware store... This car is a dialy driver so I have to have everything in line when i take it a part in order to make sure it can get back together asap

 

Those exhaust bolts are always in terrible shape. I rarely bother even trying to unbolt them and just get with the cutting right off the bat. I always thought they were some standard size because I've always just told the auto parts guy I need a new set of exhaust bolts (without springs) and he gives me a box with 3 bolts and 3 nuts.

Where did you get this information? The pipe diameter is inversely proportional to exhaust gas speed (smaller pipe, faster gasses). This is a big factor in engineering a header, if not the biggest. I've never heard this sounds suppression theory mentioned anywhere before.

 

^ What other ideas do u have? Why make that pipe 2.75 or 3 inches wide and tighten it to ~2 inches at the end? My guess is that they wanted to create a gas chamber/pillow for sound vibrations to settle down in. Topspeed or any other header for this matter provides almost equal size pipes from motor to the cat to make the flow smoother.

I have TS header and rt cat and car is MUCH louder when I floor it than it used to be even with untouched stock cat-back.

PS: I forgot to mention in the beginning that this is just a theory.

 

I had my flexpipe replaced once my Topspeed header was already on my car. I did this based on ljuka's experience doing the same thing. It stands to reason - if you have it installed with the header and cat already in place, you're sure to get plenty of length of flexpipe, which leads to less worry of stretching/breaking later on. I've had no problems with my Topspeed header since having the Vibrant flex welded in back in August or so.

 

Did you get the regular vibrant flexpipe or the one that can also be used for forced induction applications? I just got the regular one.

I think I will just go ahead and install the header, then make some marks, chop with a sawsall, tac it into place, and remove it to make the final weld, I am not expert though

 

I got whichever one was on eBay... but it's the same one Tsx536 (Kenny) got, and his TSX is boosting quite happily, so I'm not worried about that.

 

Always use a 6-point socket when working with nuts and bolts under the car because you can have corrosion from the salt use during winter which makes it easier to round the nuts.