Opinions on tailpipe exit

I'm going to do 3" ex. looking opinions & or pics on the tailpipe exit location.
I'm debating on rear exit stock location or behind the rear tires.

I like the stock location look.

Guess we all know where I stand on this one!

Maybe something like this?

Joe73 wrote:I like the stock location look.

X2

I'm with Tom77

I like behind the tire. For a little extra quietness I'd go to the bumper.

I have mine to the rear bumper but am also going to move up to 3 inch. Not sure it well look rite going to bumper but i got time to make up my mind

I like them behind the rear tires for the summer look, However in early spring and fall when our cars are out, I like to see them out the back just to see the 2 gray exhaust streams powering straight out the back. I have them out the back with Flowmaster super44's  in my 76 Cutlass.

I guess I'm old-school, I like out the back....

So, why a 3 inch system ?? More turbulence in big pipes, affecting exhaust gas flow velocity, according to folks who seem to know...

pila wrote:I guess I'm old-school, I like out the back....

So, why a 3 inch system ??   More turbulence in big pipes, affecting exhaust gas flow velocity, according to folks who seem to know...

Yup, I agree.  3" hurts performance on the low end unless you need 3" for your horsepower level.  2 1/2" pipes are good up to about 475hp.

Quick and Dirty Exhaust System Math

Easy Way To Estimate: Your intake system needs to flow 1.5 CFM per engine horsepower, and your exhaust system needs to flow 2.2 CFM per engine horsepower.

Good Way To Estimate: Take engine RPM x engine displacement, then divide by two. This is the intake volume. Use this same volume of air for the exhaust system, but then correct for thermal expansion (you need to know exhaust temps to figure things out).

Exhaust Pipe Size Estimate: A good section of straight pipe will flow about 115 CFM per square inch of area. Here’s a quick table that shows how many CFM each common pipe size will flow, as well as the estimated max horsepower for each pipe size:
Pipe Diameter (inches)  Pipe Area (in2) Total CFM (est.) Max HP Per Pipe    Max HP For A Dual Pipe System
1 1/2                         1.48                  171                78                    155
1 5/8                         1.77                  203                92                    185
1 3/4                         2.07                  239                108                   217
2                               2.76                  318               144                   289
2 1/4                         3.55                  408                185                   371
2 1/2                         4.43                   509               232                   463
2 3/4                         5.41                  622                283                   566
3                               6.49                  747               339                   679
3 1/4                         7.67                  882               401                   802
3 1/2                         8.95                  1029             468                    935

NOTE: These numbers are just estimates. All pipes are assumed to be 16 gauge steel.

The table above is probably over-estimating pipe size, but you can see that a 400 hp vehicle with a dual exhaust system only needs 2 1/4 – 2 1/2 inch pipes. Anything larger is overkill.

Great post with the exhaust data Joe ! I would agree that 3" would defiantly kill some low end torque unless your upwards of 500HP- 500+ TQ. I'd like to know what your running under that bad boy when you get a chance.

Eric

I sold my 2 1/4" thrush header back system with Stainless sonic turbo mufflers when I took the car apart.  I'll be going with a 2.5" system, probably no crossover pipe but it would be an "H" pipe if I did, Pypes Race Pro stainless muffs (got them already) and stock exits at the bumper.  I will take every effort to have it all tucked up real tight to the bottom just like factory (and Chris' monte exhaust love his exhaust).  My opinion is, since the factory can tuck it up nice, we can too.  I really dont like when I can see the mufflers hanging below the rear axle tubes.  
Here's a pic of my 2 1/4" system before I took it out.  It tucked up pretty nice.  No muffs showing.

That looks good from the rear, tucked up nice and clean, I have full 2 1/4 stainless all mandrel bent/welded,  mine gets very tight going over the axles due to my original upper control arm fatigue. I have had a hard time keeping the pipes from rubbing against my coil springs. I installed vista cruiser station wagon coils after the exhaust was done... Big mistake, I had to put in a set of air shocks and run them @ 60psi to compensate for the rubbing. My next job is the rear upper and lower control arms at that point I can run the air shocks in around 25-30lbs.

In my pic, those mufflers are "center" out just like stock. Most performance mufflers are "offset" out which usually brings the tail pipe closer to the spring. You have to keep playing with it to get it too clear. 3" is even closer.

Your absolutely rite Joe. When it comes to the Flowmaster super 44's 2 1/4".  I ordered them from summit and had shipped to Canada not realizing at the time the offset out would be such a PITA. No center-center in 2 1/4 in the summit magazine.  I've been trying to beat it over but no luck. It will take some heat and a BFPB to get it over far anuff. I have the center in offset out #flo-942447.  That's the problem when ordering out of a catalogue. I couldn't imagine stuffing 3" pipes up over the axles.
I'm looking forward to hearing from 77cruiser and what he has in mind.

Eric

Ive never seen an offset in. You sure you have them in right. Offset out works and does clear pretty easily.

I have the centre in offset out yes in right. The bends could have been made tighter going over the axle for sure. I think its mainly due to the wagon springs I added pushing the rear up to high, moving the pipes within about 1/4" from the springs. The hangers 1/2dia rod are also welded onto the pipe inserted into a fabricated rubber cushioned metal box. So it makes it difficult to move without heating the pipe itself. Its only noticeable when going over pot holes or severe uneven pavement.

Like I said, I'm old school ( make that just OLD )
The tips on my Malibu are supposedly a 70s design (?)

I have 3"center in center out flowmasters and 3" tail pipes from Torque Tech, they clear perfectly.

Hopefully the 3" system doesn't hurt I'm putting a 421 sb should be a touch over 500hp.
Plan on dynoing it within a month. I want to find out also how my new headers do compared to off the shelf dyno headers.

That nice work I must say. I couldn't imagine starting a project like that myself. I'm in shock actually. I hope they work out for you.
Cheers
Eric

Very nice work on the headers!

My car now has the exhaust out the back.  The muffler shop guy talked me into running it that way.  I don't really like it because you can really see a lot of the tail pipe from the side, and he put on massive truck style tips.  Does anyone have nice pics of a rear exit that is more factory like?  I am thinking of redoing the tail piple and going to either factory style or perhaps a behind the rear wheel exit.

Here's what I have now.

I agree. A tucked up tailpipe would be nicer. And either factory turndowns or cbrome tips would look good as well. Yours remind me of the monte ss tailpipes in the 80s. Car looks great!!!!