RTBenny

My car currently has a 3 inch ORY running though a Borla XR-1 and out the back through a single exit. With its most recent mods, it made 506whp. It a supercharged 383. Would increasing the exhaust size help at this point? When does 3 inch become a restriction? I'm not wanting to go duals.

dr_whigham

iTrader: (49)

Supercharged 383, over 500hp? I'd definately step it up to a single 4"

What size headers are you running?

RTBenny

1 3/4. I know 1 7/8 might be worth some power up top but headers aren't nearly as cheap or easy to change as the rest of the exhaust.

VandykeT/A

I'd be pretty confident saying the 3" is a restriction now. Just buy a 3" to 4" flowmaster merge. Some 4" piping and a bullet type muffler.

RTBenny

Thanks guys, might have a little project to get started on. Got free tuning for the next 11 months, might as well change as much as I can.

VandykeT/A

If you've got 11 monthes of mail order tuning. I'd get it on a dyno quick. I'd imagine a supercharger being a little difficult to tune through the mail. Good luck.

RTBenny

Nah, not mail order. Actual dyno tuning. When you pay for the tuning once, the tune will be tweaked for free if I bring my car in. I'd be terrified running a mail order on this thing.

dr_whigham

iTrader: (49)

Benny, have you given any thought to selling the current headers you have and stepping up to the larger primaries? I seriously think you'd see a fairly vast improvement with them.

RTBenny

I was just thinking about that. I'd like to see what 1 7/8 inch headers and 3 1/2-4 inch exhaust would make. It would be a good little comparison. I may just lose boost and not gain any power.

Exidous

iTrader: (11)

I am moving to a dual 3" into a 3.5" single and am N/A and will be close to maxing out the 3.5". Definitely suggest dual 3" into single 4" for a FI 383 with 1 7/8" primaries.

RTBenny

I may step up to 3.5". The car is already loud, I dread 4 inch. I might run a cutout and a really quiet muffler. That way, I can choose.

99Bluz28

iTrader: (35)

I'd go with the 4" and run it out the back so you can use a full size muffler in the stock location. Magnaflow #14153 (14" case L), Magnaflow #12594 (22" case L, with dual 3" exits), and the QTP #12400(13.5" case L). FYI the only reason the 4" would be any louder is if the muffler size doesn't increase. If you really want to run smaller than 4" then I'd run a FM3"/4" Y-merger into a 4" cut-out followed by a 4"/3" reducer going into your current 3" cat-back with the Borla XR1, or go with a Magnaflow #12579 (22" case L) if you really want to quiet it down with the cut-out closed. This will allow full flow when the cut-out is open and you're heavy on the GO pedal, but quieter to quiet with it closed.

RTBenny

That's a good idea 99bluZ28. The 4 inch dump would open it up but back to quiet with the 3 inch reducer and I don't even have to buy a muffler or all that 4 inch pipe. Nice!

Or since its still loud now, I may would put a 6 inch Dynomax bullet right before the turn down. It would clean up the sound when the dump was open and make it even quieter when it's closed than it is now. Right now the drone is pretty bad, especially with the windows up and t-tops in.

s346k

iTrader: (4)

a guy here with a 393 ls1 stroker made 530whp using a y pipe setup and 3.5" catback exhaust with a single muffler on a fd rx7.

i think you guys are underestimating the 3 and 3.5" exhaust capabilities.

m6 car went 136 na btw.

justin hover

Why would you not wanna go the TD route at this point? All 3" with an X pipe. You'll achieve the best flow this way, and the sound is amazing comparably to any ypipe setup hands down.

TImmy_Jones

iTrader: (4)

Time to upgrade! Kooks 1 7/8" headers and true duals...I bet you would see a nice gain!

dr_whigham

iTrader: (49)

And he probably would have made more with an X set-up. Nobody is underestimating anything, simply stating an X will outperform a Y.

Blackpanther99

iTrader: (8)

Agreed. X pipe simply outflows a Y pipe. Im not saying Y pipe doesnt make any power but an X pipe will simply outperform a Y pipe.