Magnaflow Mufflers are installed
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Redbob
Well-known member
BullWinkle said:
It depends on many factors, including the type vehicle - generally, you'd spend more time on a Cadillac than you would on a Cavalier - but it also depends on what your relationship is with the customer, and how much experience you have with a particular model.
Since a typical new vehicle development cycle is on the order of four years, and exhaust system design work often begins in the second year, a fair estimate would be 10,000 - 15,000 man-hours, if you're including the time making prototypes, the manufacturing engineering time, the quality engineering time, on top of the design work, drafting work, and development tests. When you have a new supplier (like Calsonic was) taking on a completely new vehicle (the C5), the number could easily be double that. I'd be surprised if we spent less than 30,000 man-hours, and I know our tooling and equipment bills ran into the millions of dollars. The fully-automated assembly final check fixture alone was $150,000. (Not many people know that the C5 exhaust was built as one assembly from the manifold connections back to the tailpipes, then serialized, unbolted, and shipped to Bowling Green as two separate assemblies for installation at two different points on the assembly line!)
As I'd mentioned, we'd been working on Corvettes, proposing exhaust solutions to GM, since late '90. We finally started production almost 6 years later.
- R
Redbob,
Why did GM decide to go with the C5 muffler inlet and outlet on the same side?
Wouldn't a straight through design like pre-C5 mufflers have been more efficient in flow?
What area of engineering is exhaust work considered to be in? I'm guessing automotive?
Is there a market for electrical engineers in the car world? I'm just curious, I'm not an engineering major or anything like that.
Why did GM decide to go with the C5 muffler inlet and outlet on the same side?
Wouldn't a straight through design like pre-C5 mufflers have been more efficient in flow?
What area of engineering is exhaust work considered to be in? I'm guessing automotive?
Is there a market for electrical engineers in the car world? I'm just curious, I'm not an engineering major or anything like that.
Redbob
Well-known member
BullWinkle said:
GM went with that muffler layout because it was the closest thing to a logical choice available to them, since the "vehicle" engineers had cleverly completed a body/chassis layout that left only that location for mufflers.
The single most important design criterion being, of course, that the car should carry two golf bags.
Pre-C5 cars, BTW, do not have a "straight-through" muffler design either, for that matter; in fact, there is a shorter internal flow path in the C5 mufflers, with fewer reversals of direction, than in C4 mufflers. That's why the C5 mufflers have such extremely low backpressure.
Exhaust work falls in the general field of mechanical engineering, as does most other work related to automobiles, trucks, etc.
Of course, there is a huge amount of work done by electrical engineers in automotive.
Regards,
- R
-=Jeff=-
Well-known member
Redbob,
I sent you a PM also but which part of the LT4 cat back is most restrictive? the mufflers? or the Resonator?
I sent you a PM also but which part of the LT4 cat back is most restrictive? the mufflers? or the Resonator?
Redbob
Well-known member
And I just replied to it; but I'll answer here anyway. You can compare the two replies and see if they match. 
While I don't think I have any data on this, my best guess is that the mufflers are more restrictive than the resonator. The resonator, although it has rather small internal tubes, is a straight-through design, while the mufflers are of a modified tri-flow design, running the gas flow back and forth internally.
Those mufflers are still much less restrictive than the ones on your '89, however.
Regards,
- R
Graham:
If you should decide to try plugging one of the tailpipes on those Magna-Flows, try doing it with the tailpipe that's in-line with the inlet pipe. That would force the muffler to act more like a stock muffler.
- R
While I don't think I have any data on this, my best guess is that the mufflers are more restrictive than the resonator. The resonator, although it has rather small internal tubes, is a straight-through design, while the mufflers are of a modified tri-flow design, running the gas flow back and forth internally.
Those mufflers are still much less restrictive than the ones on your '89, however.
Regards,
- R
Graham:
If you should decide to try plugging one of the tailpipes on those Magna-Flows, try doing it with the tailpipe that's in-line with the inlet pipe. That would force the muffler to act more like a stock muffler.
- R
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- #27
vms4evr
Well-known member
Redbob,
I definetely agree on the resonators. The tubes are small but straight through. The inlets look like the tubes would be 2" dia judging how the pipe reduces going in. We ran the car with the factory mufflers off and only a resonator. Loud and you could easily feel the exhaust flow out of the pipes even at idle.
The mufflers have a new home. But this is getting resolved. Even my wife looked at the car with the factory mufflers back on and agreed that they don't do the car justice. So in a couple of months I'm going to get back on this. I like some off the ideas I have heard. With those particluar mufflers sticking a potato, as it were, in 1 pipe doesn't appear like it would do much. The inlet diameter is 3". That big hole feeds both tubes. The tubes run straight through the muffler to the dual outlets. So the flow would be balanced on both sides. There are no restrictors in the muffler. Straight through design. The rest is the baffling material. And these mufflers are as heavy as the factory ones. I think the solution for these will be restricting flow into them. The butterfly valve and smaller diameter pipes from the resonators back seems workable. And/or dump the resonator seeing as how it doesn't work with these mufflers and place an X-pipe in there. Hopefully creating a tuneable exhaust.
Graham
I definetely agree on the resonators. The tubes are small but straight through. The inlets look like the tubes would be 2" dia judging how the pipe reduces going in. We ran the car with the factory mufflers off and only a resonator. Loud and you could easily feel the exhaust flow out of the pipes even at idle.
The mufflers have a new home. But this is getting resolved. Even my wife looked at the car with the factory mufflers back on and agreed that they don't do the car justice. So in a couple of months I'm going to get back on this. I like some off the ideas I have heard. With those particluar mufflers sticking a potato, as it were, in 1 pipe doesn't appear like it would do much. The inlet diameter is 3". That big hole feeds both tubes. The tubes run straight through the muffler to the dual outlets. So the flow would be balanced on both sides. There are no restrictors in the muffler. Straight through design. The rest is the baffling material. And these mufflers are as heavy as the factory ones. I think the solution for these will be restricting flow into them. The butterfly valve and smaller diameter pipes from the resonators back seems workable. And/or dump the resonator seeing as how it doesn't work with these mufflers and place an X-pipe in there. Hopefully creating a tuneable exhaust.
Graham
Topless
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I like this idea of butterfly valves in the exhaust system. I think it is worth trying. I am up for a test.
What size tubing would you try this with. I have a 3" system, but I think the previous owner had delusions of grandure.
Graham/Redbob: do you have a sketch of this type of system? If not, I could try to create one.
-Mike
What size tubing would you try this with. I have a 3" system, but I think the previous owner had delusions of grandure.
Graham/Redbob: do you have a sketch of this type of system? If not, I could try to create one.
-Mike
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- #29
vms4evr
Well-known member
Mike,
I don't have sketch. But look how a carburetor operates. Mainly the bottom part that less the mixture into the engine. You have the base of the carb with a rod going through it. That rod has a butterfly on it that acts as a valve. I'm thinking 3" tubing may be a little overkill and 2.5" may be more realistic. Especially with 300hp. I would assume the butterfly would be maybe 2" dia. On the outside you want a small lever on the butterfly shaft so you can manually set it. Much like how the throttle linkage opens and closes the butterfly on a carb. For purposes of the test I would setup something crude and manual. Just to see how it works. I think it maybe time for me to go dumpster diving at the salvage yard for some old rice burner that had one of these mufflers. Just so I can tear it apart and see how it works.
Graham
I don't have sketch. But look how a carburetor operates. Mainly the bottom part that less the mixture into the engine. You have the base of the carb with a rod going through it. That rod has a butterfly on it that acts as a valve. I'm thinking 3" tubing may be a little overkill and 2.5" may be more realistic. Especially with 300hp. I would assume the butterfly would be maybe 2" dia. On the outside you want a small lever on the butterfly shaft so you can manually set it. Much like how the throttle linkage opens and closes the butterfly on a carb. For purposes of the test I would setup something crude and manual. Just to see how it works. I think it maybe time for me to go dumpster diving at the salvage yard for some old rice burner that had one of these mufflers. Just so I can tear it apart and see how it works.
Graham
Topless
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- 1992 Convt w/hard top; 2004 Z06 Z16; 1962 327/300
Good idea. I may be joining you.
This setup sounds to fun to pass up an attempt.
MIke
Redbob,
Sorry if this seems like an interogation, but I just have so many questions to ask:
Would a free flowing exhaust system also reduce interior temperatures?
Those HP gain claims that manufacturer's make, that's if you do everything from intake to heads, headers, high flow cat, etc... Am I right about that? The number that, say for instance Borla advertises a 14 HP gain, is the max potential the mufflers could give you???
Sorry if this seems like an interogation, but I just have so many questions to ask:
Would a free flowing exhaust system also reduce interior temperatures?
Those HP gain claims that manufacturer's make, that's if you do everything from intake to heads, headers, high flow cat, etc... Am I right about that? The number that, say for instance Borla advertises a 14 HP gain, is the max potential the mufflers could give you???
Redbob
Well-known member
Take a look at another concept for the "dual-mode muffler'.
Arvin's Japanese partner brought an idea for a muffler where exhaust pressure opens an internal throttle valve against spring pressure trying to close it. Come to find out, F*rd offers something like this as an aftermarket (SVO?) system for M*stangs.
See http://www.arvinmeritor.com/products/car/pdfs/toyota_dual_ mode_muffler_ext.pdf
for a description of the muffler (but not a real clear one) and see
http://www.musclemustangfastfords.com/archives/tech/0102_tech02.shtml
for some juvenile M*stang magazine's description of installing these mufflers on some teeny-bopper's toy car.
Oops is my anti-Mustang bias showing?
Anyway, if you go to a wrecking yard for muffler valves (and DO NOT tell them that's what you're looking for!), look for Mitsu 3000 GT VR-4's, a Mazda 929, or maybe a fairly recent BMW 3-series. The car I know best, the Nissan Skyline, was never imported here.
I'd put a valve, whether cable- or spring-operated, into the muffler outlet pipe that's directly in-line with the muffler inlet, if this applies to the muffler you're looking at. But before you go to all this trouble, try the outlet pipe plug we discussed earlier, just to see that this concept is worth the trouble on your particular car.
And keep me posted! Sounds like fun, and you're actually charting new territory here; you know that the aftermarket muffler suppliers think that "loud" and "shiny" are the only two criteria their mufflers have to meet to get Corvette folks to buy 'em.
Regards,
- R
Arvin's Japanese partner brought an idea for a muffler where exhaust pressure opens an internal throttle valve against spring pressure trying to close it. Come to find out, F*rd offers something like this as an aftermarket (SVO?) system for M*stangs.
See http://www.arvinmeritor.com/products/car/pdfs/toyota_dual_ mode_muffler_ext.pdf
for a description of the muffler (but not a real clear one) and see
http://www.musclemustangfastfords.com/archives/tech/0102_tech02.shtml
for some juvenile M*stang magazine's description of installing these mufflers on some teeny-bopper's toy car.
Oops is my anti-Mustang bias showing?
Anyway, if you go to a wrecking yard for muffler valves (and DO NOT tell them that's what you're looking for!), look for Mitsu 3000 GT VR-4's, a Mazda 929, or maybe a fairly recent BMW 3-series. The car I know best, the Nissan Skyline, was never imported here.
I'd put a valve, whether cable- or spring-operated, into the muffler outlet pipe that's directly in-line with the muffler inlet, if this applies to the muffler you're looking at. But before you go to all this trouble, try the outlet pipe plug we discussed earlier, just to see that this concept is worth the trouble on your particular car.
And keep me posted! Sounds like fun, and you're actually charting new territory here; you know that the aftermarket muffler suppliers think that "loud" and "shiny" are the only two criteria their mufflers have to meet to get Corvette folks to buy 'em.
Regards,
- R
Do you think there is any way to do the automatic sound reducer on single inlet/outlet systems?... or is there a manual way on straight pipe systems? It would be nice to have something to put on for the highway, but be able to keep it loud for in town
Redbob
Well-known member
BullWinkle said:
Sorry I didn't really answer most of your questions in my last post, so here goes:
1. The best way to reduce interior temperatures with a free-flowing exhaust is to space the pipes farther away from the body!
Backpressure does not have much effect on exhaust gas temperature, within the range of practical backpressures. Excessive backpressure, really excessive backpressure, will result in cooler exhaust since not much horsepower is being produced.If you want to reduce exhaust heating of the cabin, put aluminum heat shields on the body above the pipes, and keep them clean. They reflect heat, and work best when they're more reflective.
2. In most cases, the horsepower gains that muffler manufacturers advertise are complete fabrications - except in the case of the L98 C4's; that car has very high backpressure, and is very responsive to a free-flowing exhaust. HOWEVER: If you'll note Graham's and others' experiences, modifying the exhaust will usually result in very objectionable noise levels in the cabin. This need to make the car quiet is why the exhaust was so restrictive in the first place, and unless you're still in high school, I'm guessing you wouldn't want to take any long trips in a car with a good free-flowing exhaust, unless the installation was very well-thought-out.
And by "long", I mean a trip of over about 15 minutes!
When you see some muffler company claiming major power gains on a C5 car, I can promise you those claims are absolute bullsh*t.
I developed the C5 exhaust, and total power loss, as compared to NO exhaust restriction, was less than 10 hp. And you only get zero restriction by putting the engine on a dyno and dumping into a vacuum exhauster.
Regards,
- R
Redbob
Well-known member
Vettelt193 said:
I'm sure you could come up with something that would work on single in/single-out systems; an example is the muffler (FR500?) offered by Ford's SVT for Mustangs. The valve that varies backpressure is inside the muffler. I seriously doubt that muffler would work on any Corvettes, designed as it was to work on the teeny V-8 in a Mustang!
Your best best would be to convert to a dual-outlet low-restriction muffler, like the Magna-Flows, and put a plug in the outlet pipe that lines up with the inlet for around-town driving.
Regards,
- R
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- #36
vms4evr
Well-known member
Hey Bob,
I haven't forgotten about or dropped this idea. I'm still doing my homework on the sites you posted and some others I'm finding. Spending the money to do it is on hold but the research is in progress. So I have another question. I need some good reading material on the resonance and harmonics issues as it applies to cars and exhaust systems. Not the rocket scientists version. Kinda like the "Blah for Dummies" books. I need to get some better detail on this. "How To Make Your Magnaflows Tuneable and Resonance Free" would be really good, but I can't find that one at the library...
;stupid
Graham
I haven't forgotten about or dropped this idea. I'm still doing my homework on the sites you posted and some others I'm finding. Spending the money to do it is on hold but the research is in progress. So I have another question. I need some good reading material on the resonance and harmonics issues as it applies to cars and exhaust systems. Not the rocket scientists version. Kinda like the "Blah for Dummies" books. I need to get some better detail on this. "How To Make Your Magnaflows Tuneable and Resonance Free" would be really good, but I can't find that one at the library...
;stupid
Graham
Redbob
Well-known member
vms4evr said:
Graham:
Maybe we could re-package the contents of this thread and publish it?
There are a number of texts out there, such as "Scientific Design of Exhaust & Intake Systems" by Morrison & Smith that have useful information in them, backed up by some theory, but I think you could expect to read several such texts before you got a good handle on the practical sort of solutions you're looking for. Still, I'd recommend looking around, and don't discount the "old" British books with titles like "The Design of Racing Sportscars" or "Sportscar Intake and Exhaust Design"; like someone said, those books are old, but so is the internal combustion engine. You might also glance at a high-school physics text for a brief explanation of organ-pipe tuning, wave behavior in pipes that are open at one end and in pipes that are open at both ends.
Part of the reason is that exhaust system development is a highly experience-based field; only those who work in the field have practical experience in it, since academics don't have access to the muffler-building and pipe-bending tools required to try out their theories. Those who do work for Arvin or Walker - or Calsonic - have always been quite careful to never write a "Handbook of Exhaust System Design" because (A) they don't want their competitors to find out any of their "secrets", and (B) if that's what you're paid to do, and it's taken you 20 years to learn how to do it, why give it to someone else for free?
Frankly, it's unlikely that the people at the aftermarket muffler shops have the analysis tools, the technical background, nor the experience to design a good exhaust system. They may well make a low-backpressure one, but it's unlikely it'll be acceptably quiet.
I'm not just some kind of environmental whacko that thinks cars should make no noise; I like the thunder of a strong-running V-8 as much as anyone, but I know it also sends out a signal to the cops - "Here I come!" - and I'm more interested in going fast than in sounding fast.
Keep in touch;
Robert
O
ocrick
Guest
Hey Redbob
Redbob...
I noticed that you used to work for Calsonic....seems like a small world...I used to work for them too. Have been in Shelbyville phase III many times.
What are you doing now?
Redbob...
I noticed that you used to work for Calsonic....seems like a small world...I used to work for them too. Have been in Shelbyville phase III many times.
What are you doing now?
Redbob
Well-known member
ocrick:
I'm now at Peterbilt in Denton, Texas.
Trying to make those big trucks quiet!
(Success eluding me, must press on regardless...)
Regards,
R
PS:
Visited Calsonic around last Thanksgiving, current management has managed to fritter away both the Corvette and Mercedes (ML-series) exhaust business.
But they have gotten Isuzu - whoopedoo!
I'm now at Peterbilt in Denton, Texas.
Trying to make those big trucks quiet!
(Success eluding me, must press on regardless...)
Regards,
R
PS:
Visited Calsonic around last Thanksgiving, current management has managed to fritter away both the Corvette and Mercedes (ML-series) exhaust business.
But they have gotten Isuzu - whoopedoo!
O
ocrick
Guest
Hey Redbob,
Looks like the slide from the "golden days" has continued. Currently, I am at NNA HQ in Gardena. I get back to Smyrna @ once a year but have not gone down to the plant. I don't know if I would even know anybody there (it's been 7 years). Maybe next time I will have to look some of the old crew for a beer at Toot's or something!
BTW... I recently got myself an 89 C4. There have been a lot of little projects need to get it where I want it.
One is the exhaust (duh!). It's loud...not "turn up the radio" loud....more like "keep your mouth open to keep your ears from explodin" loud between 1200 and 1800 RPM.
It has what looks to be a Walker aluminized Y-pipe (without cross tube) which is rotting from inside and muflers which may have significant deterioration inside as well. I am considering installation of the newer Walker Y-pipe with cross tube and either the Walker Quiet Flow series mufflers or their SS high performance series.
What do you reccomend to keep the peace in the neighborhood?
Rick
Looks like the slide from the "golden days" has continued. Currently, I am at NNA HQ in Gardena. I get back to Smyrna @ once a year but have not gone down to the plant. I don't know if I would even know anybody there (it's been 7 years). Maybe next time I will have to look some of the old crew for a beer at Toot's or something!
BTW... I recently got myself an 89 C4. There have been a lot of little projects need to get it where I want it.
One is the exhaust (duh!). It's loud...not "turn up the radio" loud....more like "keep your mouth open to keep your ears from explodin" loud between 1200 and 1800 RPM.
It has what looks to be a Walker aluminized Y-pipe (without cross tube) which is rotting from inside and muflers which may have significant deterioration inside as well. I am considering installation of the newer Walker Y-pipe with cross tube and either the Walker Quiet Flow series mufflers or their SS high performance series.
What do you reccomend to keep the peace in the neighborhood?
Rick
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