A week with no mufflers... will it drive right?

[TomCat]

Well I got it back with no mufflers and yep... it's very very loud. Not ear busting loud, kinda sounds like a WWII plane. Anyways, as far as backpressure for power... you need it! The car feels like it has lost half of its low end torque. Still screams up top, but down low it's a dog. Oh and for anyone that cares, the new tranny is awesome! I'm happy!

 

[90mustangGT]

Camman - Really, do you know how engine's work? You are one stupid SOB. They are refering to velosity. Mass, volume, and velosity. It's a lot more complex than that. So, according to these books you have read, what is an acceptable amount of backpressure, such as at idle, cruising? One pulse of the exaust on one runner pulling the exaust out of the other runner. So how does exaust pressure backed up into the engine help it run? I bet you dont' know the answer. What is the actual mass of air? The idea of an exaust system is to get the gas out of the engine, not to keep it in. Different sizes of tubing, different lengths, and even the shapes contribute to the way it performs, as well as how it was designed to remove the exaust gas from the engine. The factory designed the exuast systems with the smog test in mind and cost, not performance. What do you do for a living? Me, automotive technician, two years of trade school, seven on the job, my certifications include X1 - exaust systems and A8 - engine performance, among others but those areas include backpressure as some of the subject matter. Have you ever hooked up a backpressure gauge to an exaust system. If you want to come making insults to me. Short bus, call me a stupid, really. Prove it.

Here are some eye opening threads about exaust systems:
http://bbs.hardcore50.com/vbulletin/showthread.php?t=30103
Those are some guys that actually know what they are talking about, a lot mroe than me and most people.
Linked from that:
http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/index.html

Now that is a artical worth reading. Everyone should read that artical.

 

[90mustangGT]

Anyways, as far as backpressure for power... you need it! The car feels like it has lost half of its low end torque.QUOTE]

So, you hooked up a backpressure gauge and your backpressure dropped? I bet if you did, you would see more backpressure and erradic flow.

 

[TomCat]

Anyways, as far as backpressure for power... you need it! The car feels like it has lost half of its low end torque.QUOTE]

So, you hooked up a backpressure gauge and your backpressure dropped? I bet if you did, you would see more backpressure and erradic flow.

No... I don't have a backpressure gauge? Ok, I've just always heard that less restriction = less backpressure. Off to read those articles.

 

[Camman]

Camman - Really, do you know how engine's work? You are one stupid SOB. They are refering to velosity. Mass, volume, and velosity. It's a lot more complex than that. So, according to these books you have read, what is an acceptable amount of backpressure, such as at idle, cruising? One pulse of the exaust on one runner pulling the exaust out of the other runner. So how does exaust pressure backed up into the engine help it run? I bet you dont' know the answer. What is the actual mass of air? The idea of an exaust system is to get the gas out of the engine, not to keep it in. Different sizes of tubing, different lengths, and even the shapes contribute to the way it performs, as well as how it was designed to remove the exaust gas from the engine. The factory designed the exuast systems with the smog test in mind and cost, not performance. What do you do for a living? Me, automotive technician, two years of trade school, seven on the job, my certifications include X1 - exaust systems and A8 - engine performance, among others but those areas include backpressure as some of the subject matter. Have you ever hooked up a backpressure gauge to an exaust system. If you want to come making insults to me. Short bus, call me a stupid, really. Prove it.

Here are some eye opening threads about exaust systems:
http://bbs.hardcore50.com/vbulletin/showthread.php?t=30103
Those are some guys that actually know what they are talking about, a lot mroe than me and most people.
Linked from that:
http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/index.html

Now that is a artical worth reading. Everyone should read that artical.

A back pressure gauge... . I stick to my guns that your ignorant. Your qualifications mean nothing because you totally miss the point.

 

[90mustangGT]

Oh, a backpressure guage doesn't exist??? TU-24A, google search it. I have it, and it doesnt' take much backpressure to cause problems. It's pretty obvious you have pressure wave and backpressure confused. You couldn't answer any of my questions. Look at page two of that artical, but of course, you know more than anyone else, so of course, your above it. Your point? You have no point.

How exactly does backpressure help an engine run? ANSWER IT

With muffler flow requirements out of the way we can move on to methods of applying suitable capacity mufflers to the “system” without needless disruption of length-induced pressure wave tuning. Probably the best way to ease into this somewhat complex subject is to consider some of the published muffler test results done in recent years. These tests appeared to have shown that, sometimes, lower flow mufflers inducing at least some backpressure were required to make best power. In all such tests that I have studied, the conclusions (as apposed to the tests) were invalid. There turns out to be several reasons for this and all are relevant to building a near zero-loss exhaust system.

The first point canceling the supposed validity of back-to-back test results is due to the varied internal designs seen amongst the test pieces Fig. 8. Many mufflers are made up of a number of inter-connected chambers having varying degrees of access ease by the exhaust. Others are of the “glass pack” variety. These types represent opposite ends of a spectrum and have a substantially differing response to arriving pressure waves.

You see what they are saying, it's not the backpressure of the smaller mufflers, but how they effected the pressure waves.

Call me ignorant and stupid, but based upon what? I think anyone reading this thread can see that you (camman) don't know what your talking about. Read up on that artical, it might open your eyes to a few things. I know it did mine.

 

[90mustangGT]

C'mon man, educate me. I'm serous, I mean if backpressure is so important, I want to know why. Some info please. I'm in the middle of a 347 buildup, doing all new exaust, hell I need to know. Since you have sat down and talked with Carrol shelby, Steve Saleen, Marc Visconni, John Force about these subjects, you must really be someone special. I think I should link Jay Allen, Buddy Rawls, and Ed Curtis, maby you can teach them a thing or two about camshaft design. God, were lucky to have someone as great as you on Stangnet!!! Of course, you're probally just too good for us so you'll do what the professional adult does, just call names and not back up what you say. :Teh-Win:

 

[Camman]

I never meant to say I know more than anyone else. I will say that you do not get the point however. I am sorry I stepped on your ego. You go ahead and call any one of those gentlemen you link and ask them if you should run a straight through exhaust, no crossover, on a street vehicle. Also, where did the camshaft design come in? I have never claimed to know anything about camshaft design. This is an open forum, it is good to have differing opinions. But you sir are just plain misleading people. Since you obviously have done your research you know that telling people back pressure is not necassary is both ignorant and irresponsible of you. If you truly do believe that you should take your 2.2l honda civic and have open pipes then I will not waste much time arguing with you, read some more, broaden your scope.

edit: I dont mean to be a bick old jerk about this, and I have no doubt that you are very experienced in this subject. My point is that backpressure is not evil. It is infact good to have on most any stock motor as it will bring your powerband down into a much more usable zone, also as you realize the area under the curve is what we are looking for in a street machine. I was just pointing out that backpressure is not necissarily evil. Also, I was not saying that back pressure gauges do not exhist, but they are not usually called "backpressure" gauges. With the proper knowledge any properly ranged "pressure" gauge will work. thats all. I didn't intend to get into a big argument with you, just mearly point out how potentially damaging a statement like
"Anyone who says backpressure is nessasary for a car to run right doesn't know what they are talking about" can be in an open forum like this.