So as the title states im playing with the idea of getting a custom exhaust done from the down-pipe/header/cat back. I know many people are choosing the t1r b-pipe and an axle-back of their choice but why spend all that money when you can piece together everything yourself and have a muffler shop perform the welding.

So here is what I am thinking. Id like to go with 2-2.25in piping so around 60-70mm and id like to put a higher flow glass pack/resonator where the stock one is in the b-pipe section of the exhaust. I plan on picking up a universal Greddy TiC or HKS Hi Power muffler to finish it off.

Adding up all the parts between the resonator and muffler it will cost around 250 and then the custom piping and welding will be appx another 150, so up to 400 for the whole setup rather than spending the same for just an axle-back.

So do you guys have any suggestions or thoughts about what I am planning? Let me know if I should look into other parts or if I am on the right track. Thanks alot!

 

What are you goals or future plans for modification? An N/A Fit would be best served by 60mm or smaller exhaust. Especially if there are no intake mods planned.

Whatever you do.. if you are going to have one custom made and you are going to spend a couple hundred on it, have them V-band the sections together. Make sure you include a full metal flex section near the engine too!

 

I am planning to eventually purchase the Sprintex SC when it is available so that was a main question of mine. I know for that a 2.5 -3in would be better but until then would I lose any performance on my non sc'd fit with piping that large?

Also I dont know too much about exhausts or welding so bare with me, but can you explain a little more what you mean by v-band and the flex section? Maybe if you have a picture example that would be awesome, because its worth a thousand words

 

If you're gonna go with the Sprintex, but you are designing the exhaust now.. I would just go straight to a 70-75mm exhaust.

The flex section basically lets your engine move about on its mounts without cracking your manifold or other expensive exhaust bits.



The V-band clamps have a whole bunch of advantages.. everything from easier maintenance to a more flexible install and they seal better than traditional gaskets.






They can be used on the intake or the exhaust side of a boosted application, but are more common on the exhaust when running low boost.

On high boost systems which in my mind is over 30psi... you see these V-band clamps or wiggins clamps on both the intake and the exhaust.

Because for most people, when they go boosted exhaust pressure is just as high or higher than intake manifold (boost) pressure. This is almost always true on turbo systems. Especially poorly designed ones.

In most cases the goal is to have boost pressure and drive pressure on a 1:1 ratio.

You have a supercharger so even though you won't have the back pressure of a turbo, it will still be higher than the NA version of the same engine.

 

That flex section would probably go at the beginning of the b-pipe where it connects to the header/down pipe right? That makes a lot of sense! And those v clamps are a really good idea, i was originally just going to have them make a solid pipe from down-pipe to muffler but its a good idea to have sections to maintenance down the road.

Thank you so much for the suggestions!

I should also mention that I am trying to keep this legal for emissions, am I on the right track with the parts i listed to maintain that? I'm assuming i should be ok as long as i don't touch the cat.

 

Oh that will be tougher on a larger than stock exhaust.. you will want a highflow cat in there.. if it is too big for the volume passing through at idle it may not heat up enough. And yes the flex section goes right at the beginning of the B-pipe.

Otherwise it sounds like you are right on the mark with what you have in mind!

Glad I could help!

 

So should I put a high-flow cat where the current stock resonator is instead of a glass pack? This would then create a dual cat setup if I am following correct?

 

The heat is what lets the elements in the cat do their thing. So one cat as close to the engine as possible if you are going with a 3" ID should do the trick!

I would do this were I in your shoes:

Header>Flexpipe>Cat>Resonator>Straightpipe>Resonat or>StraightPipe>Muffler

Or something similar. With 2 resonators and 2 lengths of straight pipe I don't know if I would even use a muffler.

Another option would be to use a smaller exhaust, and then have a manual or pressure-activated (Hobbs switch) cut out.

This would allow the engine to breathe in boost with the cut out open, and then still pass emissions in vacuum with the cut out closed..

You could muffle/resonate the pipe after the cut out if you are afraid of making too much noise.

If you go this route you would just put the cut out between the end of the flexpipe and the cat.

Anyways just a thought.

Edit: Whatever you do, and feel free to be creative make sure you retain all your stock sensors and as close to their original locations as possible!

 

Lmk if you wanna buy a universal hks hi power, i was going to go this route but switched to a quieter setup so ive got one w/ ge hangers ready to go. I'm really interested to see what you end up with here

 

pm'ed ...........

 

Hi,

You got excellent advice from DSM. I'll throw in the suggestion that you also take a look at Magnaflow mufflers and cats. I've had good luck with them. There are also places out there that sell stainless steel mandrel bends and straight tubing (Burns, etc). If you are going to this much trouble, you might as well go with stainless.

Prices on mandrel bends and things like O2 bungs are all over the place so do some searching. Then find a welder you can work with.

Muffler shops can also 'puff' or enlarge small sections of tubing for slip fits which will help with your fabrication. Then you can always clamp together and take to your welder for finishing.

John

 

Thanks for the input, I think my hardest thing will be trying to get it to pass emissions once I do all this work. I am still contemplating if I was to just do this from after the cat back, so essentially my own b-pipe/axle back combo or if I want to gung ho it and replace everything from the engine back(header/downpipe) cat, res, straitpipe, muffler etc.

I am gonna need to price it all out and see if it it manageable pricewise, and then determine how emission's friendly it will be.

 

I can't offer advice, but let me know how this all goes. I may have you ship me a second one and pay you extra for a finders fee if you'd be interested.

 

i have a custom exhaust with 2.25 inch piping. i took out the second cat since there are no emissions tests in michigan. then i took out all the stock piping including the resonator and just straight piped it to my hks exhaust. with my intake it actually sounds pretty beefy

 

mmmh... this is a mod i've been contemplating for a while, but i'm going to let my wallet breath for a while...