New engine in. New problem found. Ran it with open headers, ran good. Added Y-pipe and 3" Catback. Runs like crap now.
Need:
Best <b>Flowing / Quietest</b> Header-Back suggestion anyone can make. the 3" just aint doin it...

 

Not a lot of options here since 550 horsepower is basically more than 99% of aftermarket systems are made to handle. 4" mufflex should do it, or you could fabricate a true dual system with 2.5 or 3" pipes. You may be looking at some custom work for the y-pipe. Don't settle for some cheap mashed together thing if you go that route, make sure it's a true Y at the connection to the "offroad" pipe.

What kind of headers?

 

Yep, there's not much out there for a cat-back over 3".

I guess cause most people that put that kind of HP together realize the benefits of true duals.

 

A motor like that needs true duals.

 

www.mufflex-performance.com

 

oh boy. chassis dyno results.... Catback eating 60-70 horsepower and TQ throught the entire graph... ouch eh? Working on a solution.. thanks for feedback!

 

Here's what I am in the process of doing. I had the same problem. Ran good without exhaust, slow with 3" exhaust.
I Ordered the Mufflex 4" system, took the y-pipe from my hooker super comps and cut it where it y's down to 3", extended the 2 1/2" pipe (from the y-pipe) around the corner headed towards the cat (where mine used to be), bought a Flowmaster dual 2 1/2" to single 3 1/2" y-collector, had an exhaust sjop expand the 3 1/2" end to 4" o.d., and will weld it to the mufflex as soon as I get the darn thing. (they make them to order).
This should flow plenty of air for my 383ci.
The single 4" pipe will outflow dual 2 1/2's. Besides, look how quick Spohn is running with a single 4" pipe.

 

Yeah, the 4 inch Mufflex system is supposed to be equal in flow to 3 inch duals.

 

hey just screw it all do what im doing once i get a bigger motor with power. im going with hooker super comp long tube headers, moroso turndowns from jegs and im goin to cut a section out of the turn down to throw a muffler in there the quiet it a little and then have it exit in front of the rear tires. the moroso turn downs are 3'' and 4'' pipes. i was also thinkin of tryin to find a way to put a X pipe in there too but who knows.

 

The only problem with that is that ground clearance gets to be really low, trust me I know...

 

That's why I am doing itthe way I am.....so I can keep some ground clearance.

 

Actually I believe he is running dual 4 inch, becauses I have talked to him about running duals before and he said I could do it with smaller pipes if he could do it with dual 4". I looked at his sight and I know his headers have 1 7/8" primaries and 4" collectors so that is all I know for sure, but I am pretty sure he is running dual 4" pipes.

Ben

 

Hmm.....I thought I heard he was running only a single 4"....but who knows.....I have never seen his car

 

I would want somthing like this with all that power. Well with the 3" pipes. For now I'm thinking of that remote cap.

https://www.thirdgen.org/techbb2/sho...hreadid=126944

 

i am gonna agree with the 4 in mufflex people... i have a buddy with a 94 z28 355cid port/polished heads, blower cam and a AT1 procharger running about 12 lbs of boost and runs the mufflex 4 inch... he loves it... it sounds awesome too...

 

Drag,
If you can get the 3.5" side expanded to 4", then can they expand the 2.5" side to 3"?

That would make my life easier since I dont have a cat.
I just run the headers back under the spohn tranny x mount and into a flowmaster collector mounted in the tunnel and then to the stock location modified muffler.
I need a quiet exhaust to race at tracks like laguna Sec that are sound limited to 90 db, but flange the muffle to replace with a straight pipe for open exhaust tracks like thunder hill.
Evan

 

I believe they make a 3".....look it up at Summit

 

Whatever you do, don't get dual 2.5" Friend's car was running dual 2.5" on a 500+ hp motor and switched to dual 3inch huge difference.

 

believe it or not as far as sound tolerance my friend has a 500 hp 454 in his malibu and he has dual straight 3" with the cheap $20 summit mufflers dumpin before the axels and they rob very little horsepower and are quiet for what he is workin with.... just my two cents

 

I would have to agree with that. A 550 hp engine is gonna need to breathe

 

www.drgas.com

goto the nascar link.

I'm ordering 9ft of the 3 1/2 inch oval pipe,2 round to oval adapters for Hooker Long Tubes,aX-Pipe. & 2 spintech muffs.
SORTA like this
but more sized for a 3rdGen

Gona run 4th Gen tips out just befor the rear tires like this picture


Im picking up the supercomps next saterday. but might be a month or 2 befor I have it all in. Gona order a Roadtech k-member and A-arms 1st also..

Later
Chris@cecoatings.com