imported_ksyu1

Hi..I have a intake and header installed on my car with stock cat converter and stock exhaust..I was wondering is it worth it to change to a highflow cat converter and a full catback exhaust..or can I just change to a high flow cat converter with a muffler using stock piping and still get noticably better flow..thanks alot for your advice

1sykcoupe

U have an si so the pipes already pretty good. if u do go with a catback pipe u shud proli do 2 1/4. I believe thats the reccamended size. Put on a high flow cat and a aftermarket exhaust and u'll be good.

Nova_Dust

What is your header collector size? 2.25", or 2.38"? You can do a catback with a minimum 2.25" mandrel bent application. Cat wise, I would leave it stock.

1sykcoupe

paul at splitifire said crush bending and mandrel bending both give same results. if its crushed right. mandrel is usually twice the cost of crush bent. maybe a waste of money.

chris_si98

dont mean to sound like a dick.. but if you have a d16y8, your wasting your money. The stock systems flow well enough for the stock CR, actually if you upgrade your going to suffer whatever low end your car has.

imported_ksyu1

thanks, you guys are really helpful..yea I guess I dont want to waste too much money on bolt ons for a d16y8..so im thinking about just getting a muffler..anyone recommend one thats not too loud with a deep tone? and where I can buy it/price?..thanks you guys own!

Nova_Dust

Crush bending reduces pipe radius at the crush angle, for obvious reason. Exhaust flow is measured at the narrowest pipe diameter. Crush bend and mandrel bent will only be identical in flow if you increase the pipe diameter at the crush angle.

i.e. 2.5" mandrel bent vs 2.5" straight pipe + 3.5" (as an example) crush bent arm will most likely yield the same flow result.

For muffler, you could go with magna flow, or type R muffler.

WayFastWhitie

Oh wow, i just lost more respect for these people, not that i had much to begin with

1sykcoupe

splitfire is a dick but i've heard this more than once.

imported_ksyu1

how much do people usually charge for a muffler + welding..sorry guys for the noob questions..thx

Nova_Dust

If you buy a bolt-on, labour should be next to nothing, provided your bolts are not seized. (1/2 hour job)

If you buy a generic muffler, what they might do is chop up the old muffler, reuse the pipe and do a quick mig weld. Again, that should be relatively cheap as well.
(1 hour job)

Nowadays, shop labour is about 50 to 70 dollars an hour, that should give you an idea. Time is estimated.

imported_ksyu1

thanks for your help!

VTEC_Thunder

There isn't a HUGE difference from crush bend to mandrel bend pipes, but there is some. If you look at your exhaust like a river of flowing fluid (which it kind of is) in the bends, the fluid flows more so to the outer side of the bend, and is more turbulant in the inner part of the bend. So in a crush bend, where the ribs are on the inner part of the bend, there isn't too much resistance cause the flow is already turbulant there, and the outer edge where most of the flow is, is still smooth and flows well.

So there are some gains to be had from mandrel bends, but not much on a stock vehicle.

High flow cats help alot (from my experience), you may want to get a universal magna flow high-flow cat and slap it in place of the original, and also put on a universal muffler.

Magnaflow make excellent exhaust products.

I have a tanabe muffler, without the cork it sounds great. Not too loud, and it's mostly low mellow sound (untill vtec hits...heehee)


Hope that helps

DumbasSi

I had a stock 99-00 SIR cat converter, midpipe and muffler on my old 98SI. The SIR exhaust was a bit bigger in diameter then the stock SI exhaust. It "felt" like it fowed better and it definately sounded nice.

Like mentioned above, dumping alot of cash into a relatively stock D16 is a waste. Spend the money on suspension parts because IMO its much more appreciated.

VTEC_Thunder

imported_ksyu1

wow very good inputs here..yea right now im thinking of getting a magnaflow muffler and a magnaflow highflow cat..but alot of people have told me that the magnaflow cats wont pass emissions or they stop working after a couple of months..can anyone confirm this? thanks

imported_weiRtech

i hope you're kidding. mandrel bends will outflow crush bent in any situation, particularly with boost.