Exhaust System Cost

[lkt1954]

Local muffler shop just quoted me approximately $ 800.00 for an exhaust system from the headers back to exit behind rear wheels with magnaflow mufflers.

I thought that was high until I looked at systems on line- $ 700.00+ Flow Master, Magnaflow, Hooker).

Here is the set up on my 69 C10 SWB no cab or bed on the frame at this time: 350 engine-TH 400 transmission- exhaust pipes to run through the frame at the driveline crossmember- coil over shocks-trailing arms- rear fuel tank- pipes to exit behind read wheels.

Is $ 800.00 a good price for a custom exhaust or is there a better priced system to use that the one listed above? I have a son-in-law who can tig weld when he isn't on shift work.

Any thought would help.

[geezer#99]

You can buy mandrel bent kits for a bunch less.
Lots of different ones available.
Here’s some from summit.



https://www.summitracing.com/search/...r-exhaust-kits

[MikeB]

Because your pipes run through the crossmember, a system from Flowmaster, Magnaflow, etc. won't work w/o modification. However an installation done by a local shop will probably use crush bends instead of mandrel bends. Crush bends can reduce flow by 20% or more.

If your son-in-law can TIG weld and has a chop saw, you can do it yourself using mandrel bent sections and straight tubes. I've done just that on two vehicles over the years. On both of them I used tailpipes that were mandrel bent, one pair from Flowmaster, the other from Heartthrob Exhaust.

As far the muffler shop's price quote, it seems a little high to me, but Magnaflow mufflers aren't cheap, and neither is labor these days.

Nice smooth bends here, not crushed:

[68post]

Originally Posted by MikeB

Because your pipes run through the crossmember, a system from Flowmaster, Magnaflow, etc. won't work w/o modification. However an installation done by a local shop will probably use crush bends instead of mandrel bends. Crush bends can reduce flow by 20% or more.

If your son-in-law can TIG weld and has a chop saw, you can do it yourself using mandrel bent sections and straight tubes. I've done just that on two vehicles over the years. On both of them I used tailpipes that were mandrel bent, one pair from Flowmaster, the other from Heartthrob Exhaust.

As far the muffler shop's price quote, it seems a little high to me, but Magnaflow mufflers aren't cheap, and neither is labor these days.

Nice smooth bends here, not crushed:

This is what I do also, just bought enough to do 2 of my trucks since the price hasn't skyrocketed yet on the pieces, (steel shortages have increased my wholesale garage door price up 93+% in 12 mths). Most pieces are from Summit, but one muffler from Amazon (one in stock only) - the other Summit, and Flowmaster mandrel bent tailpipes from Ebay. All aluminized and mandrel bends, with H-pipes too.

[Ziegelsteinfaust]

Engine Masters did a exhaust comparo. At roughly the 500hp level crushed pipe did not make a difference. Not going to watch again tonight.

Headers, mufflers, and number of bends do more damage to hp.

[crazy longhorn]

I should get pics of the underside of my truck....If I had to pay it, it would have been 800-1000 in the shop! It has a shorty set of headers/mandrel bent downs, tucked tight.....straight shot to the mufflers/H pipe. The rear (tail pipes), are also 2 1/2, but crush bent. Not hard , but easy on the bends.....headers to the back, I have 250-300 in the system! I worked in that muffler shop, & had the use of that shop(sat/sunday)& the pipe cost me a buck a ft. The old man donated a set of 50s Flowmasters (used but not sold, donated). That old truck has an awesome sound with that 5.3! Longhorn

[Dead Parrot]

Type of pipe? Size of pipe? H/X pipe included? Type of fitting at the header-exhaust connection? Warranty type and length? All of this will impact the price.

Will your son in law provide "warranty" work 6 months after doing the initial job? 3 years? Are you prepared for the job to take several days or even weeks if you have to wait for a replacement piece to arrive after one gets destroyed during the install?

[MikeB]

Originally Posted by Ziegelsteinfaust

Engine Masters did a exhaust comparo. At roughly the 500hp level crushed pipe did not make a difference.

What diameter pipes were they using? If 3" or more, it could be that they still had plenty of capacity to handle the engine's exhaust flow, even after being crush-bent.

Found this on a LS tech-geek site:

Mandrel 2.5" duals have a combined area of 8.819 sq. in.
Crush bent 2.5" x 2" oval tubing duals have a combined area of 6.958 sq. in.

That's a 21% restriction.

But you don't need math to simply look at both type bends to see which one will flow the best.

[MikeB]

Also, even a mandrel bend is an obstruction to flow, so the larger the radius of the bend, the better.

Finally, David Vizard recommends using adapters to install mufflers that are one size larger than your pipes. That's a simple and cheap way to make more power.

[Ziegelsteinfaust]

Originally Posted by MikeB

What diameter pipes were they using? If 3" or more, it could be that they still had plenty of capacity to handle the engine's exhaust flow, even after being crush-bent.

Found this on a LS tech-geek site:

Mandrel 2.5" duals have a combined area of 8.819 sq. in.
Crush bent 2.5" x 2" oval tubing duals have a combined area of 6.958 sq. in.

That's a 21% restriction.

But you don't need math to simply look at both type bends to see which one will flow the best.

I think they did both 2.5, and 3 inch.

Bends the way they cause a restriction in hvac duct work, and I believe it is the same in cars. Is by increasing the effective total length.

In hvac a 90* adds anywhere from about 40 to 100 total equivalent feet. Depending on type of 90*, and pipe sizing.

So if those numbers hold true for a typical over the axle bends on a car it can be from 160 to 400 equivalent foot. Where as a truck would be less since in all likely hood it would be less severely bent to get over the axle due to extra real estate. Thus reducing total equivalent feet.

Car-Craft years ago had a dyno test where a 350sbc with close to 500hp on tap lost 25-30 hp/tq in the meat of the power band due to a over the axle mandrel bent system vs a typical turn down set up. So I always run turn downs for power, and straight through mufflers. I will use the longest one possible, and a shorter one or resonater if I want quiet.

My 07 gmc rcsb with a 4.8 first thing I did was exhaust. I had a Flowmaster super 44 3" put on for the sound, and hopefully pick up some power. I used a turn down, and while peak power did not change. My mid range or meat of the band really felt stronger.

So after watching the episode. Which I will watch tonight as I have tomorrow off so I have free time to watch it. I am less likely to concentrate on the piping as much as I used too, and now concentrate on the parts that effect power more. Which are headers, mufflers, and system layout. Atleast at the power levels I play in. Which are in the 450-500 hp

[Ziegelsteinfaust]

Originally Posted by MikeB

Also, even a mandrel bend is an obstruction to flow, so the larger the radius of the bend, the better.

Finally, David Vizard recommends using adapters to install mufflers that are one size larger than your pipes. That's a simple and cheap way to make more power.

Exhaust system design does not make power it keeps it. And most mufflers are the same from 2-3 inch. Plus cheaper ones 3" is necked down to 2.5.

Straight through mufflers typically do not cause a big loss of hp or much of to begin with. So buying a 3" magnaflow likely will not do anything. Unless the case is physically larger vs a 2.5 version.

[MikeB]

Would be interested in looking at the exhaust systems on the new 600+ hp cars, like Dodge Demon and Corvette Z06. It's probably easier to reduce bends on the mid-engine Corvette.

Speaking of Engine Masters, they did a show where they tested several exhaust configurations, and as I recall, having 3-ft lengths of 3-inch straight pipe behind 3-inch collectors was one of the best things you could do. Minimal obstruction on the way to the mufflers.

I'm not challenging Car Craft, but was surprised to hear about their test where over-the-axle tailpipes killed so much power. I've always thought that lots of the energy was given up as heat by the time the exhaust got back that far. I've even heard that in a 2.5" system, using 2.25" tailpipes would not hurt a thing.

Sounds like you've done some HVAC work. At my last job, one of the items our company sold was flow meters. Learned all kinds of things about properly sizing piping and how piping bends affect flow & flow measurement. Bends play havoc with flowmeters, so a meter typically need to be a certain number of pipe diameters downstream and even upstream from bends to make accurate readings.

[MikeB]

Originally Posted by Ziegelsteinfaust

Exhaust system design does not make power it keeps it. And most mufflers are the same from 2-3 inch. Plus cheaper ones 3" is necked down to 2.5.

Straight through mufflers typically do not cause a big loss of hp or much of to begin with. So buying a 3" magnaflow likely will not do anything. Unless the case is physically larger vs a 2.5 version.

Well, of course you don't want to use a necked down 3" muffler! That would be the same as using crush bends. Performance mufflers that I'm familiar with are not necked down.

About exhaust not making power, now you're nitpicking. Exhaust will affect how much power the engine makes. So, I'm not sure what you meant there.

[Ziegelsteinfaust]

Originally Posted by MikeB

Well, of course you don't want to use a necked down 3" muffler! That would be the same as using crush bends. Performance mufflers that I'm familiar with are not necked down.

About exhaust not making power, now you're nitpicking. Exhaust will affect how much power the engine makes. So, I'm not sure what you meant there.

It is about the details when deciding on exhaust, and much of it is on personal preferences. Not typically ultimate power.

A few cheaper mufflers can be necked up from the Chinese factory.

Most mufflers use the same case for differing sizes of exhaust pipe.

If your engine makes 400hp for simple reference in a perfect scenario like a dyno. If you want ultimate power. You watch the details so you loose as little as possible.

So by choosing less efficient headers you loose 10hp, choose chambered mufflers another 10. Go up and over the axle you loose 20hp from 2000-5000 rpm.

Yes all those things are what required to fit in you car lots say. Along with keeping your sanity as you drive.

So your 400hp motor 380 hp.

[crazy longhorn]

The way it was explained to me, by a man with 45yrs in the buisness.... After the mufflers, you can cut the pipe size down & really no issues on the power. Also on the crush bent pipes, the bigger the pipe, the harder it will crush it. I saw that, working in that shop I shot for mandrel downs/ straight shot to the mufflers.....after that, your exhaust has cooled down, & it does not need the larger pipe to maintain the power? Check that with the Pontiac guys (forget the names), but they showed on the drag strip that smaller tail pipes did not hurt the times! On your average street engine, I would doubt that you will see much difference......all out race, you will want all you can have Longhorn

[Ziegelsteinfaust]

Just watched the crushed vs mandrel exhaust engine masters episode.

On a 540hp LS3 the exhaust systems killed 10 hp from open headers.

Mandrel bent was 1.7hp and 2.9 tq peak to peak over crush bent. With a few spots opening up to 6tq, and back to even.

Funny thing was no big loss of tq with full exhaust, but rather a constant 10 hp. I wonder if that is something to do with the LS intake manifold having better resonance then a typical sbc dual plane?

[Mike C]

We paid $900 for a local shop to build the exhaust on my kid’s Jimmy. And we provided the mufflers. We ran 2 1/2” Corvette manifolds and there is no off the shelf bolt-on solution.

We ran 2 1/2” all the way and used some 6’” round cased Magnaflows because I had them from a parts truck.

I had two takeaways from different Engine Masters episodes: 2 1/2” is plenty for 500 whp and the Dynomax turbo mufflers are fairly cheap, pretty quiet and didn’t cost any real power.

[lkt1954]

A lot of great information here and I appreciate it.

Dead Parrot said what I have been thinking all along about getting my son-in-law to do the tig welding for me. While I think $ 800.00 might be a little steep, it does get a turn-key job done and in a short period of time. This is a project I'm building for a grandson as his first truck- so a little less horsepower might not be a bad thing.

Thanks again.

[68post]

Originally Posted by lkt1954

A lot of great information here and I appreciate it.

Dead Parrot said what I have been thinking all along about getting my son-in-law to do the tig welding for me. While I think $ 800.00 might be a little steep, it does get a turn-key job done and in a short period of time. This is a project I'm building for a grandson as his first truck- so a little less horsepower might not be a bad thing.

Thanks again.

Nothing wrong with supporting your local economy and neighbors !!

[GASoline71]

Originally Posted by Ziegelsteinfaust

Headers, mufflers, and number of bends do more damage to hp.

??? You meant stock manifolds right?

Gary

[Ziegelsteinfaust]

It was more of statement of headers which I am more familiar with, and have only a passing knowledge of exhaust manifolds.

Either way you choose a less then optimal option. You get less the optimal results. Obviously everything is based on engines hp/tq levels, and end users wants. Either you, me, or the next guy.

Long tubes are almost always better then short tubes, and the gap narrows as hp levels drop. Even when tube size is the same. Engine Masters had a episode where shorts made more power everywhere in a single exhaust set up.

Some manifolds are better then others, and improvements can be made to them to enhance them even further.

So as a blanket statement proper selection of exhaust including headers will improve a smogger engines power level. Rather or not it matters to the end user.

[truckdude239]

I paid 650 for 28nch front to rear with knock off flow masters

[TrybalRage]

I paid $1200 or $1300 for a manifold-back dual 2-1/2" stainless system. Behind-wheel exit.

I have two cats, a crossover pipe, magnaflows.

I could have cut the cost a lot by using aluminized pipe and no cats, but we still have visual emissions inspection here in PA and I didn't want any hassle.

[MikeB]

Ah, yes. Engine Masters. Solid roller cams, electric water pumps, no vacuum advance, very few carbs with chokes. Dyno charts that start at 3500 rpm, with no concern (or way to test) throttle response in the real world! Most episodes are concerned only with peak horsepower numbers at around 6,500 RPM. Fun to watch, but virtually no relevance to street-driven vehicles. I recently saw an episode where they mentioned "mid-range power", but their idea of mid-range was 4500-5000 RPM!

That said, I did watch a couple episodes where they tested smaller carbs and dual plane manifolds, but those shows are rare. Maybe I'm wrong, but I think most guys would like to see various components tested on street engines that make 350-400hp and spend most of their lives between 1500 and 4500 RPM.

[AcampoDave]

^^^ totally agree. I really enjoy the show more when they keep it real.