New 352 Exhaust System

[Deanj]

It's just about time for a new exhaust on my 1960 352. I like some recommendations from our members. I think there's plenty information on this site, but heck if I could find it. I decided that the expensive clone system from Larry's or Mac's just isn't worth the cost unless you have a show car.

I have a shop that specializes in exhaust systems and makes their own with mandrel bends as long as it is aluminum. My concern is what do they use as a template? Would they replicate my current system which I think was Midas shop proposition? Do I even consider going to a 2 1/2 inch system?

Second, if I stay stock 2 inch system, what mufflers are we talking? There are the stock clones-and I'm good with the factory sound, or there could be could be the Magnaflow multi-chamber 24 inch 4x9 ovals which appear to be an option.

Dean

[simplyconnected]

Dean, a 'custom-built' exhaust system is by far the best you can ever hope for. Those guys don't simply buy the cheapest pre-bent pipes, they buy better quality 'aluminized-steel' tubing (not aluminum) and they use their skills to fabricate your car's system. Custom pipe jobs tend to be made from thicker tubing that lasts far longer.

I chuckle at your question about the template. Like a plumber electrician, heating guy, etc., they look at the 'canvass' and plot their course based on the requirements.

OEM exhaust is always 'purchased' and bare minimum to meet Ford's requirements for sound, size, clearance, etc. Now, it's your job to tell your exhaust guy exactly what your requirements are. Put his skills to work.

Deep 'throaty' sound comes from a combination of, your engine's cam, pipe diameter and your choice of muffler (or sound chamber). If you change any part, the sound will change.

The real advantage here is, you get to work with your installer and he will use any components you buy. The size of pipe is incidental because the bends are the same. Talk with him, let him know your wishes, then listen intently to his suggestions. - Dave

[Deanj]

Thanks Dave. I feel more confident about the exhaust system. The mufflers are a different story. I like the stock sound, but I'm not stuck on it if there's a better choice. It "sounds" as if mufflers are totally whatever I want even if I know little about these.

Dean

[simplyconnected]

I had a 5.0 Mustang GT convertible. I knew I was replacing the engine later with a 351W which has the same bore but 1/2" more stroke. Basically the same engine with more torque.

In the mean time, the OEM crossover "H" pipe failed. So like you, I found a shop that fabricated exhaust systems. I bought 3-chamber Flowmasters with the idea that they are quieter than 2-chamber. They sounded great with the 5.0's 2-1/2" pipes.

The same exact system, when married with the 351W was so loud the radio was useless. What was the difference? The camshaft with more duration. Both engines required premium (93-octane) gas so the compression ratios were close to each other.

[Deanj]

Dave, I agree the cam affects exhaust sound the most. I took a 190 HP L48 Corvette where the cam went flat and replaced it with an Erson mild performance cam and a free flow cat. Good thing I kept the stock exhaust because I wouldn't have been happy with any performance mufflers.

Would you think a 2 1/2 inch exhaust system would help the 352 or kill the scavenging effect of a small pipes? Could this be another you won't know until you try it?

Dean

[pbf777]

Would you think a 2 1/2 inch exhaust system would help the 352 or kill the scavenging effect of a small pipes? Could this be another you won't know until you try it? Dean

Yes!

When weighing potential performance, one would not generally consider a 2-1/2" diameter exhaust system to be excessive on the typical American V8 at 352 cu. in., but may feel somewhat shorted, although probably sufficient in the as delivered T-bird, with a 2" system.

This proves to be a very complicated discussion concerning a multitude of considerations; such values as engine capacities, camshaft timing values, induction tuning, intended performance applications etc.,etc., and with this information one may proceed in an attempt to determine the "ideal" exhaust system with considerations of pipe diameter(s), lengths, which include placement of expansion chamber(s), effects of bends & transitions, and even presentation to atmosphere, and let's not belittle visual presentation; all of which is compromised (in this application) to fit under, without impacting body panels or suspension components or the ground, and provide reasonable exit from the vehicle.

A.K.A......... A SCIENCE PROJECT!

As far as for your concerns of scavenging effect, again remaining within something of reasonable (2" vs 2-1/2" diameter), if one considers the O.E.M. camshaft timing values and the cast iron "block" or "log" exhaust manifolds and their effect on the flow path, I don't think there will be that great of an effect on the flow column within the pipes, within the difference of these diameters.

But, you never know until.........

Scott.

[simplyconnected]

...Would you think a 2 1/2 inch exhaust system would help the 352 or kill the scavenging effect of a small pipes?..

In earlier days, we used 'H'-pipes with a tube that connected both sides of the exhaust just below the transmission. Later, the industry went with full-diameter 'X' pipes. These are crossovers that connect both input pipes with both mufflers.

Since all fluids take the path of least resistance, by connecting both sides of a dual exhaust system, in affect we just cut the resistance in half starting at the 'X'. Think about that. Now, both pipes and their mufflers handle the same pressure and sound that only one handled in the past.

Equal length tube headers don't contribute much advantage until engine rpms are up there. So they won't help much getting groceries but they will on long interstate trips, provided your overdrive hasn't sent engine speed too low.

I assume your exhaust system guy will use an 'X' pipe. I also assume you won't look for low times at the track. I see nothing wrong with a dual exhaust system in 2" for the 352. If you're not comfy with that you can always go with 2-1/4".

Let's do some math on the cross section of both pipes...
Area of a circle is equal to Pi times the radius squared.
The radius of 2" = 1" so 3.14159 times 1" times 1" = 3.14159 square inches.
The radius of 2.25" =1.125" so 3.14159 times 1.125 times 1.125 = 3.976 square inches.
The area difference is nearly a whole square inch larger in the 2.25" tube over the 2". Again, not a big difference in city driving but it's huge at and above 4,600 rpm. - Dave

[Deanj]

Dave and Scott, I think both of you are right. I found this interesting web site on exhaust system calculations.

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

It seems a 2" system for a stock 352, actually 357 after a rebuild, is probably adequate, meaning everything else is a waste of money. I've wasted a lot of money before trying to uncover a few HP which can't be felt or appreciated.

It's always a let down when you find out there's nothing to gain from an upgrade.

Dean

[simplyconnected]

Oh boy, I read the article and they left a whole lot out. Length of the system and number of degrees of bend makes a lot of difference in back pressure. They mention nothing about an "X" or "H" pipe.

I showed how to get the area of a pipe. How the article can be so far off on a 2" pipe is beyond me. They claim the area of a 2" diameter = 2.76 square inches. No it's not, it's Pi or 3.14 square inches.

I think the article is a very crude 'tool' to give the reader peace of mind. At least, it shows a difference in pipe sizes. - Dave

[Deanj]

Dave, you're right. In fact every calculation is off. I guess they right when they said it was an estimate. Maybe they figure in a few non-mandrel bends, ha ha.

Dean

[pbf777]

Oh boy,.....................
How the article can be so far off on a 2" pipe is beyond me. They claim the area of a 2" diameter = 2.76 square inches. No it's not, it's Pi or 3.14 square inches. - Dave

Yes, a somewhat simplistic article, but I believe, that was the intent of its' author. It seems mostly concerned with the understanding of flow sums thru simple tubing, with a goal of establishing the flow volume vs. diameters, and perhaps to spark some basic insight as to one's true requirements.

As far as the math, I believe the author is calculating the approximate area available based on the fact that the dimensional nomenclature for such tubing is referencing O.D. dimension not I.D..

Scott.

[lake bird]

muffler choice

I presently have a set of thru mufflers on the cross pipe ends
pretty loud, anyone have a preference for a nice sound just not
to loud....probaly just have the last sections make at a local shop or run them out the side not over the axle...

[StealthSRT10]

I got my exhaust done about 5 months ago. Its just true dual straight pipes turned out before the rear tire, Like the old racing thunderbirds. its 2 1/4inchpipe.Pretty loud if i step on it but super quiet on freeway. untill you drive by a concrete median lol. it just sounds so **** good

[Wyldie]

Oh boy, I read the article and they left a whole lot out. Length of the system and number of degrees of bend makes a lot of difference in back pressure. They mention nothing about an "X" or "H" pipe.

I showed how to get the area of a pipe. How the article can be so far off on a 2" pipe is beyond me. They claim the area of a 2" diameter = 2.76 square inches. No it's not, it's Pi or 3.14 square inches.

I think the article is a very crude 'tool' to give the reader peace of mind. At least, it shows a difference in pipe sizes. - Dave

Hey Dave

Here is an interesting Video I'm sure you will get a kick out of on the subject

https://www.youtube.com/watch?v=azPKIjxmmdU&t=646s

[Deanj]

Since the new exhaust system installation, the exhaust manifold exhaust pipe connection leaked and was repaired twice. My shop said something about trying a copper crush gasket before maybe fabricating a new pipe. I’m having a hard time understanding exactly what the issue is. All I know is after driving about 100 miles, the exhaust gasket starts leaking really bad.

I assumed that the set up required an asbestos – metallic type donut gasket. Can anyone explain what a copper crush gasket is, how it’s different and how it works.

Dean