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Exhaust Thread

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Just wondering if anyone has used a Megan Racing muffler? and if they like it or not?

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A lot of people in this topic really need to read up on exhaust theory.

 

exhaust.jpg

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there is more than backpressure at play, there is also exhaust velocity...read back a little at some of the info I posted before sticking a 3"+ exhaust on your mostly stock 4 banger.

 

I can't talk too much about oversized exhaust because my Naps is running dual exhaust...but I did it for sound and looks, and fully realise that I am loosing 5hp or so because of it (scavenging be danged!) :D

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From Spade's post

What I have found works well to get a deep tone for 4 cylinder cars, is using a VERY long glasspack close to the engine, and a small muffler near the end of the car. A 24"+ long Thrush glasspack with a Borla or short(12ish inches) glasspack at the tailpipe works well. I know some of the non-baffled/louvered ricer mufflers that would normally be too loud and high pitched can be quieted and sound perfect with a long glasspack used as a resonator.

 

 

i am very interested in this method, what brand of glasspack would you guys most strongly reccomend? my family has been using cherry bombs since before i was born, but i have heard a few negative comments about 'bomb's glasspacks

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cherry bombs are ok, they will be quieter than the thrush or other straight through option, just keep in mind, they are slightly louvered, not as bad as some glasspacks, but they will not flow quite as well. That being said, they still flow quite well.

 

Most parts stores will let you see inside the box if you ask, if you see little louvers, grates, or other protrusions that stick into the exhaust expect it to be quieter, but not flow as well. Thrush and a few other brands use a wire screen or will use holes drilled into the center pipe. because there is nothing sticking into the path of the exhaust this reduces turbulence and increases exhaust escape velocity and reduces some back pressure.

 

Remember, if you get a 30ish inch straight through glasspack and it is still too loud, you can either use a exhaust turn out (a bend at the end of the pipe lowers volume, I think it is about 1.5 Db for a 45 degree turn down, if i remember correctly) or you can use a smaller high flow muffler on the end and not have to worry about the notorious high pitch fart sound.

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cherry bombs are ok, they will be quieter than the thrush or other straight through option, just keep in mind, they are slightly louvered, not as bad as some glasspacks, but they will not flow quite as well. That being said, they still flow quite well.

 

Most parts stores will let you see inside the box if you ask, if you see little louvers, grates, or other protrusions that stick into the exhaust expect it to be quieter, but not flow as well. Thrush and a few other brands use a wire screen or will use holes drilled into the center pipe. because there is nothing sticking into the path of the exhaust this reduces turbulence and increases exhaust escape velocity and reduces some back pressure.

 

Remember, if you get a 30ish inch straight through glasspack and it is still too loud, you can either use a exhaust turn out (a bend at the end of the pipe lowers volume, I think it is about 1.5 Db for a 45 degree turn down, if i remember correctly) or you can use a smaller high flow muffler on the end and not have to worry about the notorious high pitch fart sound.

 

spades, thanks for the tip. I went with a long thrush and a slightly wider pipe from cat to muffler.

 

datmuffpipe.jpg

 

the thing is actually pretty dang quiet now but only because the previous muffler had deteriorated pretty badly. I like the tone (or lack there of I guess!) but really like that the slimness of the Thrush lets everything be tucked up very close to the floorpan. I hate exhaust that can be seen hanging down under a car.

 

I did go for a small portion of a rice though:

 

datmufftip.jpg

 

a co-worker had the fartbox tip laying around and since it was free.......it's got a few scratches on it (the discoloration on top is actually a reflection of the black bumper edge though) but the shine overall is pretty slick!

 

I paid $29 for the Autozone off-the-shelf muffler and my guy charged me $50 for the new pipe, hangers, labor, etc so I have about $80 in an exhaust system that is new from the cat back.

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In response to using fart cannons in the back, the only time I have a major issue with them is when people straight pipe back to them, it is hard to make anything sound good with a 4 inch fart can...I have heard V8 mustangs that were riced out with a fart can, and they sound bad...it is hard to make 8 cylinders sound that high pitched, but a ricer muffler does it with ease.

 

With that being said, all it takes to fix that is what you did, a glasspack in the middle of the car. It will deepen the tone and get rid of the rice sound...and the exhaust velocity will not be hurt too bad because it is at the end of the pipe.

 

So, if it works, go for it! Also, keep in mind you can expect that if this is a daily driver, in about 6 months or so some of the glasspacking will deteriorate. Not by a large amount, but enough to where it will get slightly louder. Also, on paper, a muffler or resonator by the cat will help increase efficiency, which would explain why I see more manufacturers placing resonators right after the cat.

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A lot of people in this topic really need to read up on exhaust theory.

 

exhaust.jpg

thank you. i know that my lack of exhaust tuning is probably not netting me much if any horsepower but i dont have the money or care to fix it. but i do know a fair amount of exhaust theory. more than most people think i would.

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thank you. i know that my lack of exhaust tuning is probably not netting me much if any horsepower but i dont have the money or care to fix it. but i do know a fair amount of exhaust theory. more than most people think i would.

 

I just went thru this topic again and didn't see anything really out of line from you other than a tone preference.If you are after a"sound",then knock yourself out and enjoy.If you are after HP,then you don't know as much as you think you do.Guilt must have caused you to put up your last post....months later.

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O.K After reading some of the post here I was more baffeld that the muffler on my freakin car. So I went to the shop here in town and had them run a

2 1/4 dia with a magnaflow turbo it sounds just about right and runs a little better. Went from 1 3/4 So not really that different but it sounds better.

Not loud at all. Just right for a 4 banger..

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Hey, sorry new here, if I step on toe cause I did something wrong, let me know. What is the diameter of an exhaust doughnut for a 79 210 with the 1.4L A-14 engine, the nuts holding mine in took off and I lost the doughnut some where on the road during the rains we had.

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You could always build the header to the cam specs and the desired RPM range. I dont remember the formula off hand but will look for it.

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I have 3 inch stainless exhaust from headers back to a Thrush chambered muffler on my Wagon with a VG30, I am possibly considering a 2.5 inch exhaust since the 3 is so damn huge its the biggest obstruction under the car. The car runs awesome and sounds great as is but I just dont want to hurt the performance it has already, not sure if 2.5 will help or hurt. Any thoughts?

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I have 3 inch stainless exhaust from headers back to a Thrush chambered muffler on my Wagon with a VG30, I am possibly considering a 2.5 inch exhaust since the 3 is so damn huge its the biggest obstruction under the car. The car runs awesome and sounds great as is but I just dont want to hurt the performance it has already, not sure if 2.5 will help or hurt. Any thoughts?

A 2.5 will not hurt it.

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I'm running an S14 SR20DE NA approximately 180hp. My exhaust is 2.25" from the down pipe back. There's a 12" Cherry Bomb glasspak that has a perforated ID that does not protrude into the exhaust flow right at the exhaust manifolds down pipe. Outback is a Magnaflow muffler, no fart cans here. The sound is awesome when tooling around and not to bad on the highway but it gets loud and raspy when getting into the throttle and sounds like dual webers on a GT3 race motor. Likely due to the dual overhead cam 16 valve design. I tried one of the Cherry Bomb Turbo mufflers out back and it was way louder and raspier than the Magnaflow so it got sent back. I wouldn't mind cutting the exhaust down 10 decibles for hiway running for those long 15 hour drives to NC via Summit Point 510 gathering each year.

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ran the pipe through the crossmember on the 521 build 3 inch with v bands 

null_zps35065a2f.jpg

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It may be a littile late in the thread but according to the book Maximum boost the exhaust size should be calculated to flow at @225 feet per second at peak torque for a turbocharged vehicle. There are a lot of factors that will go into calculating that IE displacement, pressure ratio (boost), volumetric efficiency, RPM,  air fuel ratio and average exhaust temperature (to calculte density). There are obviously other constraints that must be consitered like tubing only being avalible in cerain sizes and what size tube will fit in the vehicle. Having said that you can simplify your equasion by basing it off of estimated airflow+fuel flow as it accounts for 8 to 9% of your exhaust content by weight I'm just not sure how to adjust that for the change in density in the exhaust

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Hi everyone,

 

i own a 521 1.3L truck that has a rusty-broken-ready to be replaced exhaust pipe...

 

I found that the silencer(muffler) has also been damaged by rust...And i was wondering...

 

I have in my garage a stock rear silencer from a 1.4L catalytic 2008 car....Not a truck,and over 10mm bigger pipe diameter....Could i get it on?Would there be any engine problems ar it will do its job without problems???

 

 

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AND...as Driftease brought up already, turbo exhaust done correctly will be VERY different from an NA system.

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