Kinda curious how people like the 4in exaust? Hows the ground clearance and the sound??Any pics? Have 3in flowmaster cross flow now. Want something diffrent. Please post!

I love mine....the ground clearance is awesome and the sound is good. I have the 4inch with the spin tech muffler ( single out)
Just click the link in my sig if you want to hear it.

Man..pretty aggressive sounding..I LIKE

I have one with a flowmaster and I couldn't be happier with it

my buddy's old Ls1 car had a 4inch mufflex. it sounded great but i just dont like how it only has 1 exit. i like dual exits.

for the most part the fit and finish looked great. You only really need a single 4 inch exhaust for big hp numbers tho. i'd stick with a good 3-3.5 inch catback if your not planning on anything big. I will be running a 3inch single for now when my 383 goes in. i'm looking for near 500hp too on motor, so i know a dual 2.5 or single 3.5-4 is in order

I emailed mufflex and they recommended a 4" for anything over 375 flywheel hp.

there are guys making that to the WHEELS using good 3inch stuff.... i dont buy their claims

I don't disagree. but, here is the email

I really recommend 4'' for any motor making 375+ crankshaft HP. 3rd and 4th
gen systems have some different mounting points for hangers so they will not
work without fabrication involved
Thanks Denny,
www.Mufflex-Performance.com
609-890-0481
----- Original Message -----
From: ">
To: "Mufflex" <mufflex@comcast.net>
Sent: Tuesday, December 25, 2007 12:41 AM
Subject: Support form - Mufflex

With in my experience you can make power with a 3 inch and short tube headers for that matter too but with my 357 vortec head engine and a factory LT-4 cam I dropped a half second and gained 5+ MPH by switching from TES headers and a 3 inch exhaust to hooker long tubes and a 4 inch just my experinece

I picked up quite a bit from getting rid of my old single 3 inch and moving to a dual 3 inch. Buuuuut for the past year I've been wanting to quiet the car back down and run a single 4 inch with the Spintech.

yeah I find my 4 inch with a flowmaster to be a good compromise between all out performance and obnoxiously loud my friends 5.0 with 3 inch pro dumps is just too much IMHO

FWIW, I was just at the dyno last weekend with my friend. He pulled off his 4" spintech, and put on a 4" Ultraflo. Picked up 24 rwhp just with the muffler change. Tuning in more fuel (less back pressure, more airflow) ended the day with an additional 62rwhp..

Take a look inside a spintech, before you decide to install one...

Yea.. I've seen with my own eyes how bad spintech flows...With a head flowing machine.. Flowmaster flowed better..Glass packs the best. But hate how they sound.Ew. But love how spin tech sounds!

Holy crap, thanks for the heads up!!

I've run spintech in the past, really liked the sound. Don't recall hearing the ultraflo but may look into it.

Totally missed Mikes post!!!

I have had a Mufflex 4" system for a few years now. Just replaced my SpinTech muffler with a Dynomax Ultraflo. A year ago.. I went to a Dyno Day and put down 450/455 rearwheel. 13.2 AFR's

This past week I went back to the same dyno and right off the bat put down 474rw with a 14.x AFR. Added fuel to make the AFR's where they need to be.. and put down 511/501 rw, that tells me the SpinTech was holding me back....

YMMV..

Rick

That is AWESOME. Can you tell us the PN of your Ultraflo muffler?

Thats awesome to know. And to think I was gonna get spin tech. More than likely get a flowmaster kit. But the ultraflow sounds pretty sweet!

how is the sound of ultraflo? is is loud at idle and part throttle?

You still can, just get yourself an electric cutout to make up for the loss when racing....

Yea..I dunno. I don't really want to mess with cut outs. One more thing to mess with. Has any one here used ultraflow? Never heard of it till now.Any sound clips??

Dynomax UltraFlo part #: WLK-17538

http://store.summitracing.com/partde...5&autoview=sku

Mike seemed to think the idle was "louder" just at a deeper tone. Cruise is just really quiet compared to the SpinTech. The SpinTech had this tin can sound to it.. and loud at cruise/part throttle.


I had an UltraFlo back in the day and loved it, 3" in with dual outlets on Dr. side. (just like the SLP system)

I dont have any sound clips.. I will try to get some this week..

Rick

Cool - I will get this muffler also.

I'm actually running an ultraflo with dual outlets on the 3" system I have now. I like it - not too loud, not too quiet. But I'm upgrading to 4" this spring. Thanks for the info!

i'm at a loss of what to do with my 383. either a single 4 inch or dual 3. single 4 will use ultraflo. dual 3" will use powersticks like i have now on my single 3

FWIW, when you do the math and calculate the "cross-sectional area," the single 4" is about 12.6 sq in. and dual 3" is about 14.1. Not as big a difference as I thought it would be.

Wow, that much power over a muff change? I bought a 4 in mufflex used and it has a flowmaster on it. I might to look into the ultra flow. That's some jack for a muffler, $200? Damn. It costs money to go fast.

Seems like alot of ppl are picking up with free flowing exhausts. i may consider my true dual 3inch ideas and possibly ultraflos if i need to keep noise down

Yep.. its called bottle necking. If the air can come in.. and cant get out fast enough. Hp is limited. Free up the bottle neck and wonderful things happen..

Well as they always say.. " Wanna play .. gotta pay!" HP dont come cheap.. especially "reliable" hp...

That sounds great. I think I am also going to go with the Mufflex four inch exhaust. I want to run the Dynomax bullet muffler instead of the Spintech. Did you have to elimate any suspension parts where the pipes go up and over the rear axle? If so did it affect the handling. I have a set of weld in subframe connectors installed on the car but I would still like to keep the vehicle safe on a road course.

I just swapped my Spintech for that Ultra-Flo PN# WLK-17538 muffler on my 4" Mufflex last weekend. Man let me tell you it's like night and day. I had to add more fuel at WOT. I used to have consistant 113-114 mph trap speed in the 1/4. I went to the track last weekend and ran a 11.64 @ 120 mph with a 1.68 60ft on the first pass, I added more fuel at WOT and backed it up with a 11.66 @ 122 mph with a 1.80 60ft. So all you guys thinking about getting a 4" mufflex don't buy it with a spintech or flowmaster. I have proof in my hand what a Dynomax Ultra-Flo can do. And it sounds pretty good too.

thats REALLY hard to believe that the spintech held you back roughly 60-70hp. that is Huge just for a muffler to do that.

7mph in the 1/4 is HUGE. there must have been a big difference in weather that gave you some more power as well.

I know what your saying, I was baffled myself. I just scanned my time slip of both runs. On the second pass I had to let off at the top of second because I was breaking loose. Well I can't get the link to work so I guess you'll have to go to the Dragracing forum for the time slip. I can't attach the same pic on this thread.

thats running the setup you have in your sig right?

Thanks man for the props. I'm going back to the track tomorrow and see what happens on the bottle. I'll post results.

thats a very nice combo something i was considering doing. Gives me some hope my combo may be near that in power. I think i'm gonna run ultra flo's on my car

Do you think a 4 inch Magnaflow muff would yield the same results?

I didn't have to make any changes at all. I didn't have to elimate any suspension either

is the tip 4"? it would look like a diesel i think...

Where can I pick up 4in pipes with that amazing sound "1FastZ"?
I loved that sound. What would I have to do to it to make the pipes fit?

i believe summit and jegs sell 4inch exhaust pipe sections. I may be goin 4inch single or else true dual 3inch havent decided yet

Would it be stupid to put on a muffler or does that defeat the purpose

what do you mean? A muffler wont hinder too much performance if it is a good muffler, but will quiet it down some. Open exhaust is TOO loud for street cars

oohh ya trust me i kno that one. had to cut off my old muffler cuz it was too rusted. drove w/ no muffler for a week while i waited for the new muffler to arrive

You don't even see the exhaust tip on my car.
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Other than Mufflex, I don't know where you could get them. Maybe a diesel place would sell the 4 inch pipes

ooh ok cool.

Hey "1FastZ" Could you possibly put up a few pics of your exhaust setup underneath. That would be cool. Thanks.

These are the only ones I have

Is that a muffler it is hooked up to? If so what kind is it? Where could I pick this setup at? A truck shop or what. Mufflex really didnt have anything I could find.

Thanks "1FastZ" for bearing with me hear. I just love the sound and is EXCATLY what I'm looking for the sound.

Thanks again

what were your ets? I am considering doing a 3.5" catback if i can get only the intermediate pipe from mufflex.....i want my Hooker Areochamber!!

You got to look under there web site a little. Forgot what its under. Had that problem too.