Exhaust exit location?

[ksquared 13]

I'm approaching a point where I have to decide how to finish my exhaust system. Engine is a moderately warm 428 making hp in the mid 500's with a solid roller. Trans is a 4spd. 90+% street driven with a little autocrossing. Not looking for a quiet Lexus. Don't want the dreaded drone either. Thinking about Magnaflow's or whatever. Question is should I exit out the back or side pipes just ahead of the rear tires? Probably running 2.5 to 3 inch exhaust. Don't know what's available or wise yet. Suggestions? Warnings?

[BuckeyeDemon 211]

I have had side exit and given the pipe is almost under your ear, the sound will be dramatically louder as compared to out the back. Plus out the sides they will almost be pointed directly at your neighbors homes....

[barnett468 418]

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hello . . i would suggest the following as one option.

 

exits on the side are pretty loud as BuckeyDemon says [ok actually they are really f'n loud with a high horse engine, lol] and kinda defeat your goal of not being "too loud" imo . . i had them on a few cars including a big block cobra and a 65 shelby and they really drove me nuts.

 

with 500 hp, i would run 2 3/4" to 3" pipe . . if you use an x pipe with 2 3/4", i seriously doubt if will cost you any hp overall . . the problem is that there is incredibly little room for 3" over the axle and next to the gas tank so it would take a near miracle worker along with a big wad of cash to do that.

 

a straight thru muffler will have the least hp loss . . anytime you put a bend in an exhaust pipe it can cost you some amount of hp.

 

as far as headers go, you need ones that have the same or bigger opening size as the heads and have 1 7/8 tubes . . you can loose overall hp if you go too big too.

 

heres a dynomax muffler sound comparison video the double wall stainless mufflers shown at the 4:30m mark will be drone free and the quietest straight thru mufflers i am aware of and are good to 1000 hp and would be one of my choices for your app . . i would also avoid "chambered" mufflers for your noise and drone level goal.

 

 

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Edited December 23, 2014 by barnett468

[LindenBruce 27]

Ditto Buckeye. Out the back will be quieter for the occupants and your neighbors. Take a look at Dynomax also. And go with a 2.5" pipe. Anything bigger and you will hit fitment issues for sure. B.

[Rsanter 152]

Dual 2.5" pipes is a lot of pipe

The bigger you get you will get to the point that you can loose scavenging ability at low RPMs. You may loose a little off the top but unless you plan to be at those higher RPMs a lot the bigger pipes are not worth it

Out the back for sure to keep things quiet. Also you need to look at other places the noises come from.

With headers the collectors will give a lot of noise.malso you will get some noise from the intermediate pipes in the tunnel.

How to quiet that?

A couple of ways. Have the headers ceramic coated inside and out as well as the intermediate pipes. Or use a header wrap around the collectors and intermediate pipes

 

Bob

[1969_Mach1 333]

I can't speak for exit location but Borla has high end straight through design mufflers. I had a set with 2.5 inch inlets and outlets installed on my Mach 1. These are 304 Stainless Steel, (not polished) and very well made. I don't have the interior drone with them but I also have my exhaust exit in the stock location for 1969 Mach 1's. I don't know why you don't find Borla mufflers on many muscle cars. In my area of Northern California Borla mufflers are used frequently on late model dirt track stock cars so they are fairly robust.

Edited December 23, 2014 by 1969_Mach1

[LindenBruce 27]

Can you post a video on your exhaust with the Borla's? I'm interested. B.

[BuckeyeDemon 211]

Can you post a video on your exhaust with the Borla's? I'm interested. B.

 

 

 

3" sportsman XR1 (12" body)

Edited December 23, 2014 by BuckeyeDemon

[rwcstang 201]

if you are running leafs, I suggest 2.5

 

here are some pics to let u see how close they get to the leaf brackets but they did fit. Im also running magnaflows.

 

here is a video of my magnaflows

 

Warmed up:

 

Cold Start:

 

 

 

[rwcstang 201]

Ill take more pics tomorrow of the completed setup its been raining down here and I have no garage, not trying to get my clothes wet lol :(

[Ridge Runner 1,113]

I have 2 1/2 inch into and out of 4o flow masters, exiting the side of my 35 Ford truck .The motor is about a 400 hp 302 ,it is loud .I am going to run it out the back . My 65 Shelby was the same way but with glasspacks ,if i happened to step on the pedal with someone beside me i really got a dirty look,sounded good though.

A buddy has borla's on his Fox Body and i really like the way it sounds .

[1969_Mach1 333]

Can you post a video on your exhaust with the Borla's? I'm interested. B.

 

I wish I could but I have no way to record a video. Mine are Borla's Pro XS series, 14" long case and 2.5" diameter inlet/outlet. Actually they sound similar to the video clips BuckeyeDemon has posted in this thread only mine are a fair amount quieter. You'd think they would sound similar to the Magnaflow mufflers of similar construction but they don't. I also have a 3" diameter X-pipe which people tell me has an affect on the sound. I don't know because I have always had the X-pipe on it.

 

Like others have posted in this thread, 2.5" tail pipes are about the max that will fit over axles and between the rear leaf springs and fuel tank.

Edited December 23, 2014 by 1969_Mach1

[BuckeyeDemon 211]

3" is doable but tight.

 

 

 

 

[mustangmike6996 34]

I have 3" on my 69 with a 331.

 

I got a flowmaster kit and it was worth it.

[1969_Mach1 333]

Nice 304 Stainless Steel exhaust BuckeyeDemon. I see the grey color inside the tail pipes, what type of fuel are you running? I cannot find any shops in my area that will work with 300 series Stainless Steels, only the 400 series stuff and then they want a fortune for the material.

[BuckeyeDemon 211]

Nice 304 Stainless Steel exhaust BuckeyeDemon. I see the grey color inside the tail pipes, what type of fuel are you running? I cannot find any shops in my area that will work with 300 series Stainless Steels, only the 400 series stuff and then they want a fortune for the material.

 

i mix a little race fuel in it when i go to the track (i think the last time was Sunoco 110 leaded). the lead turns the pipes and plugs a little different color.

[barnett468 418]

i mix a little race fuel in it when i go to the track (i think the last time was Sunoco 110 leaded). the lead turns the pipes and plugs a little different color.

 

 

Killer car.

[barnett468 418]

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you can gain around 1/4" more clearance if you run shackles like the ones below because the nut will be on the other side.

 

http://www.drakeautomotivegroup.com/Store/Category/Suspension/Leaf%20Springs%20and%20Shackles.aspx?wid=141&page=2

 

 

you may loose some hp with 2 1/2" pipes.

.

[beecj0 11]

BuckeyeDemon, what brand is that. I have the magnaflow 3" ss, yours looks a lil nicer.

[BuckeyeDemon 211]

BuckeyeDemon, what brand is that. I have the magnaflow 3" ss, yours looks a lil nicer.

 

custom made with 304 using borla mufflers. I sanded and polished after it was built.

[JXL 12]

Some advice that I can give is to go straight out the back using some nice tips and the rear vallance with the two cutouts for the tips. I have the vallance without the cutouts so when I ordered my flowmaster kit I ordered the one where the pipes end with two turndowns just before the vallance. I find this causes a major bass sound inside the car at idle which I personally find annoying. And if there is any dust on the road it causes a major dust storm.

[1969_Mach1 333]

JXL, it may also be the Flowmaster mufflers causing the deep interior noise at idle. That's a common characteristic of many of the Flowmaster mufflers. I know the original 40 series are bad in that respect. The 50 series are a little better. The 70 series, which is too big for these cars almost sounds stock. To help reduce that deep resonating interior noise Flowmaster has offered for many years the Delta Flow version of most of their mufflers, including the 40 and 50 series. Lastly, large diameter exhaust tips that some people like also increase exhaust noise.

[JD08 42]

BuckeyeDemon, please don't take this the wrong way, but your undercarriage is a work of art.

[BuckeyeDemon 211]

ok, thanks. happy holidays!

[LindenBruce 27]

Thanks for the video links guys. It really helped. B.