2 1/2 or 3" Exhaust in Stainless or Aluminumized?

3 inch stainless with mufflers on the kids 62 300.All mandrel and the guy charged him like 325 for all.That was about 12 years ago.Rocky

Rocky,
I've gotten estimates for around $1,600.
Using the 2.5" aluminized pipe only lowers the costs about $300. The expense is in the labor and custom Mandrel bending.
The system is installed from header flange to bumper with those special clamps, "X" pipe, Custom Stainless mufflers and fully serviceable too. Sounds like everything else on this build. OVER BUDGET!

aluminum vs steel on heat is that aluminum is so good at moving heat that it gives it up quicker too.
steel holds on to it longer. takes longer to heat up, takes longer to cool down.

so you will bake things longer next to steel exhaust vs aluminum.

not sure how much it matters due to wall thickness, but it will be noticible.

..why mandrel bends?

I seldom inner purge when welding SS tube, but my experience is it often forms nodules/burrs inside when tig welded, and likely not reachable or visible when welded on long tailpipe sections, and for max flow, that bothers me, FWIW.

That sounds like a ton of cash.The guy that did my kids did it at the time from the manifolds back.He even supplied the SS mufflers.My kid did cut them when he installed the custom headers he bought used.Another guy here was going to make him a custom set of headers for 1200 bucks.I didnt think that was a lot.You can buy TTIs exhasust for around 700 IIRC.Rocky

Thanks for your comments.
Do TTI's fit on a spring relocated to the frame rail and narrowed rear set up?
I need to look into them, I don't think my mods are anything radical that would affect exhaust routing. The only issue might be attaching the TTI's to the Schumacher Tri Y's. ?
As far as issues with the welds, I don't think there will be many welds, most of the connections will be those flat band clamps at service locations.
Nothing is in stone yet.

Just read on TTI's site foot note #57
Leaf-Springs relocated
MUST USE FUEL CELL..........

2.5 is plenty.The F.A.S.T. series cars use 2.5 and they are in the 10 second bracket.

I would go with the three inch system to start with, I also wouldn't have bought any brand of Tri Y headers , but that is me I had set of 2.5 inch pipes coming out of a set of Hooker A body 1 7/8 inch A body fenderwell headers into a set of 2.5 Turbo muffs and then a short set of tail pipes(side pipes almost) on them exiting in front of the rear tires on my 1969 Dart GTS with a mild 440 bracket motor, that car ran 3 runs in the 12.2s E.T. at 109.+ MPH with exhaust hooked up at the old LACR drag strip in SO CA on Friday night, I removed them and the car ran 11.39 at 117.+ MPH on the next three run I built another street and strip car several years later and put a three inch sytem on it with the same headers and that car would run 7.02 in the 1/8 mile at 97.3 MPH through the exhaust sytem that ended at the rear bumper on that car, 1971 Duster with a pump gas 518 C.I. low deck stroker motor, that car ran 6.98 at 97.5 MPH with the exhaust system removed I ended up figuring it was the weight of the exhaust system that made the car a tiny bit faster, not the exhaust sytem restrictions I had the exhaust shop used aluminized 3 inch pipes and a set of 14x7x3 side inlet and center outlet oval Magnaflow muffs mounted behind the rear end exiting at the rear bumper That system flat worked well BTW I used the stock Duster gas tank on that car, but the head pipes from the headers had to go under the rear end (do to the coil over shocks blocking the stock pipe locations over the rear end housing ) and then bent in and up to go between the stock inner sub frame and the outer 1/4 panels I ended up buying the old dart back and bought a 3 inch exhaust system from Summit and had it welded into place the same way, it has the leaf springs moved into the sub frames so the muffs and tail pipes are ran the same way as the Duster but the pipes do fit in the stock location and those pipes go over the rear end housing into the muffs beside the 1/4 panels Those Summit brand muffs sound a lot like and look similar to the Flow Stoppers muffs

I have 3" under my 66 Plymouth Satellite just saying ..

So Cab, do you really think that in your example of going from 109 to 117 mph was because of the restriction of a perfectly good 2 1/2 exhaust system and nothing else? What is that, like 80 hp on a pretty mild motor?

I have more than one example of going from a 2 1/4 compression bent system to open headers that netted 2 mph in 12 second cars.

Obviously your experience is your experience, but logic suggests to me that possibly something else was at play in your example.

i can't believe that mandrel bends would do anything.

I went through this last year when I re-did my exhaust. I was looking at 2.5 or 3" and Aluminized or Stainless...I decided with 2.5 Aluminized. Not because of cost factor but because the sound of the pipe and clearance under the car.

I was quoted (converted from Euros) $650 for 2.5" Stainless. The problem with the stainless is that the wall thickness is super thin so it is going to resonate much more.

I put 1/2" Stainless flanges on my exhaust because I may want to disconnect portions down the line to remove the trans lets say. Why Aluminized and not SS? Who is going to crawl under my car to see something I paid so much for? I had 12 yrs on the last system and it didnt oxidize or discolor.

I think 3" is overkill. Thats just me....I have 2 1/2" pipes into Flowmaster 70 series mufflers (Diesel).

What will you run H or X pipe? That was what I battled more with than anything on the work....I went with an H but I also installed exhaust cutouts and it SURE IS FUN!!

Can't say about Alum vs. SS, but TTI tech said when I bought my system that 2.5" was plenty enough for 500HP or less. The 3" system I have looks bad-ass under there, and even though it fits really well, it does occupy a lot of space, and clearances are minimal. Springs, tank, shocks, and brake hose are factory located ('72 RR). In retrospect, 2.5" would probably have been better.

BTW, wife's '09 Toyota has factory mandrel bent exhaust, so there must be something to it.

I bought the TTI 3" X-pipe system out to the rear bumper. Car has stock gas tank and wheelwells and it fits fine. I went with 3" as I knew my new eng was going to be close to 600 hp and I race it capped up. Ron

I'm wanting the "X" pipe. Truth is I really dont know witch one would be better, I just like the look of the X
Spoke with the shop owner and he said if I post that his shop did my exhaust system, he would do the job for $1,100 out the door. 3" Mandrel bent Stainless with Custom Stainless Mufflers too.
No special tips, just turned down at the bumper.
I think thats hard to beat considering not having to do any work other than opening my wallet

that price is crazy..

For you guys that think (know) the price is high. Try pricing it locally for yourself. And for us too
Apples to Apples; Header to bumper in 3" SS Mandrel bent with SS mufflers installed.
First, few shops have Mandrel Bending Equipment and even with standard bending, their prices are not much cheaper if at all.
Let us hear your legit quotes.
What does bother me is that someone mention that the SS may be noisier than with the Aluminized pipe
That would SUCK!

I built my own 3" on my Charger with an X pipe all the way to the rear bumper with Flowbastard mufflers. I have less then $300.00 into mine including the mufflers. As all the local exhaust shops told me. Throughout an 8-10 hour day they could do up to 15 cat back or exhaust repairs ob different cars at several hundred dollars each or a custom like my car would tie up a hoist all day so $600.00-1000.00 was the going rate. Sorry no pics. Here is the finished product out the rear thru the stock tips.

you must have gotten the "Flowbastard mufflers" on sale!
Good for you man.
I've priced it and theres no way around here for even twice that!

I would only go 3" if the engine is over 550 HP, or it is a race car. The 3" will be louder than the 2-1/2" if using the same type mufflers. The mandrel bent exhaust does flow way better than the standard crimped bends. The rest comes down to cost and looks. Stainless should last longer and can be polished up for a show car, but is more expensive than the aluminized exhaust. Custom bent would be best if the person does a good job, but this again usually is more expensive than buying a kit off the shelf.

I went 3" with a mild 413 in my challenger, simply because it didn't cost that much more over 2.5 and would be one less thing to change when I go more motor.

Far as price, hard to beat the systems jegs/summit sells, which are for headers, not sure which you'd need.

I have aluminumized on my cummins, 2 winters with lots of salt, no rust even showing on it yet.

I went with the 3" stainless, X pipe and mufflers all from Magnaflow. It fits and no rattles but it is tight in places. I also installed four stainless mufflers and it is still pretty loud. I also installed two turbo style stainless clamps on the pipes where the turn up to go over the differential. These clamps are reuseable and easy to remove. Remove the clamps and the tailpipes and rear mufflers come out. Unbolt the header collectors and the entire exhaust system is out in less than ten minutes.

Here's a few pictures.

Pic 2

The fuel tank was custom built for this one but a stock tank would fit here with no problems.

Nice! Thats what I needed to see, WELL DONE!

I don't think I have room for multiple mufflers and I don't want it to be too loud. Options? Are stainless mufflers louder than others typically?

Being SS has no bearing on sound.It just depends on the muffler type.I have Summits 3 inch SS on the 65.Exits in front of the wheels.Just has a deep throaty sound.Been on for 8 years and still look great.If I went all the way out back it would be quieter.I believe you can run 2 1/2 out the back with springs moved in.3 inch I dont believe will fit unless the tank is narrowed.Rocky

curious, has anyone weighed a 2.5" system over a 3" system?

As was stated already, I don't think the material the muffler is made from determines how loud it is. The muffler design has the biggest effect on how loud they are. In my case, both styles of mufflers I used are very low restriction units. If you hold them up and look through one end you can see directly out the other end. That was the main reason I installed two on each pipe.

1) As it has been stated; a good 2.5" system will support over 500hp without issue.

2) yes mandrel bends matter

3) and exhaust system is a SYSTEM and many/most people underestimate the importance of muffler choice; the difference between a crappy flowing muffler like a Flowmaster and a good one like a Dynomax Ultra-Flow is HUGE.

3" pro's
- all other things being equal (mufflers, mandrel bends) then the 3" has room to grow if you want 600 or 700hp later.


3" cons
- price
- space restrictions (like the fuel cell note above) can make install and working on nearby components more difficult.



Dave

Very well put "Out of the Closet"! Bravo.
You summed it up in one post.

P.S. I'm only bowing at the neck, not at the waist. I don't want any misunderstandings.

If you really want to get technical and figure the exact size pipe and muffler you need for maximum flow with the minimum amount of noise, here's a long but very good read on header, exhaust and muffler design.

http://www.superchevy.com/technical/engines_drivetrain/exhaust/0505phr_exh/

Just read all the posts. First of all, I'm in the Motor City & don't know of ANY regular exhaust shops that have a mandrel bender. I know companies that can mandrel-bend exhaust tubing, but they won't work on someone's car. You can buy mandrel bends & cut & weld the system together, but that is very tedious. I have no problem with good muffler shop compression bends - if the shop has a good custom exhaust man. Also, muffler shop machines (Huth or Ben Pearson) are not made to bend stainless tubing - bending 304 or 409 require too much tonnage for most muffler shop machines. Be aware too, there are muffler shops that do the smooth compression bends & will tell you they are mandrel bends. You should use 16-gauge tubing, whether it's stainless or aluminized. NO muffler shops build exhaust systems out of ALUMINUM! It won't take the heat. As far as stainless types, 304 is the good stuff & is non-magnetic, & it will NOT corrode at all. 409 stainless IS magnetic, & it will get rust & corrosion, but not as extreme as aluminized steel. NEVER let anybody use non-aluminized steel tubing to fab an exhaust system with - it will begin rusting overnight. NEVER use thinner 18-gauge tubing even if it's stainless no matter what grade.

As far as diameters, at around 500 HP & under, 2.5" is probably the right diameter. If you are going to be street driving mostly & not at the drag strip, then 3" would probably be overkill & you may lose some low-end & midrange performance. The right diameter system will give the exhaust flow velocity. Choose mufflers that FLOW WELL! I wish I would have known this back when I had my Hemi Charger back in 1981 - I used some stock Chrysler Hemi mufflers from Mitchells & they flowed like crap! I should have used some Walker Redline Z's back then.

STAINLESS PIPE (304 grade) produces a "ring" & many guys prefer the sound & cooling efficiency of aluminized steel. If you want the best flowing stainless oval mufflers on the market, there is no better choice than the Dynomax Ultra Flow stainless with the stock-looking spun-locked heads. NOTHING flows higher sCFM's than them. Good luck. Hey, the place that is going to mandrel-bend a system for you, ask them what kind of bender they use? I'd like to see if they will even tell you.

I went with the Pypes 2-1/2" Stainless/ X-pipe/ Race Pro Muffs, for my 68 Barracuda. The price was very reasonable and it's mandrel bent. It was less expensive than the locally non mandrel bent 2" system EDIT plain muffler moly, non aluminized I had installed many years ago. Even factoring in the install, the Pypes system is a much better deal. YMMV.