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AHHHH......... FLOWMASTERS

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With the tune on my truck engine it lost power when running open headers......

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If you lost power with open headers it was due to your fuel mixture being too lean, not from opening up your headers.

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Depends. Seat of the pants while trying to accelerate OR on an engine dyno spinning 6500+?

Assuming trying to drive on the street/trail:

With open headers you will lose bottom end due to the loss of scavenging. You do have to make some minor adjustments to compensate from the lack of backpressure if trying to run open pipes, but nomatter what you do, you will "feel" a power drop on the bottom end (where most of us "drive"). Just like cam size, you have to comprimise on one end or the other.

You are correct if it were for am all out racing engine as you would increase top end (from the better ability to breath), but it doesn't sound like that is what the poster is doing.
 
I hate to tell ya Timmy, but the sound also depends on the type of cam you run. With a higher duration cam that overlaps more, you're gonna have a deeper, louder sound than with the stock cam in which you are probably running. There are a lot of factors that come in as to how loud they are going to sound. Also, are you running the original's or the delta flows? the delta's are a lil bit quieter, but scavange better and are more ideal for DD's.

NITRO
 
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With open headers you will lose bottom end due to the loss of scavenging. You do have to make some minor adjustments to compensate from the lack of backpressure if trying to run open pipes, but nomatter what you do, you will "feel" a power drop on the bottom end (where most of us "drive"). Just like cam size, you have to comprimise on one end or the other.

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Completely untrue. If your headers are the proper length and size, all of the scavenging effect that you're going to get will come from them. Everything after that is restriction. I have gone over this time and time again to back it up. Do a search. I have througly beaten this dead horse. Anything you can do to reduce restriction increases power.

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I hate to tell ya Timmy, but the sound also depends on the type of cam you run. With a higher duration cam that overlaps more, you're gonna have a deeper, louder sound than with the stock cam in which you are probably running. There are a lot of factors that come in as to how loud they are going to sound. Also, are you running the original's or the delta flows? the delta's are a lil bit quieter, but scavange better and are more ideal for DD's.

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Since you missed what I posted a number of hours ago, I'll post it again so you dont even need to scroll up.

Flows do sound good on big engines with big pipe and lots of cam, but I personally think mine sound like crap.

To answer your questions:

I am running the original flows.

Delta flow or not, flowmaster is one of the poorest flowing mufflers on the market so your arguement may hold true in a comparison to other flowmaster mufflers but the reality is that damn near any other brand will out flow and out perform a flowmaster so that point is essentially moot for anyone unless they are only considering one brand.
 
AHHHH, YES........FLOWMASTERS


Love them Super 40s!
 
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Headers?? no way. Not gonna mess with them! in my opinion, NOT worth the trouble on a daily driver that see's the snow! They'll rot out in a year or 2! I went with regular 40's.

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I've had mine nearly 4 years now and they're still fine.

Get coated ones.
 
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Completely untrue. If your headers are the proper length and size, all of the scavenging effect that you're going to get will come from them. Everything after that is restriction. I have gone over this time and time again to back it up. Do a search. I have througly beaten this dead horse. Anything you can do to reduce restriction increases power.

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I agree, but off the shelf headers are designed to be used with a collector and "moderate exhaust". Most are "tuned" for a sbc350 (in our case) with a moderate exhaust. A "tuned" header with proper length pipes and proper ID size and proper common chamber volume and length will give the best performance, but not with ones you buy off the shelf (contact any header manufacturer if you don't believe me).
 
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Here we go again /forums/images/graemlins/shame.gif

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Just hate to see somebody given misinformation.

The sad part is Tim is right (in a particular instance), but considering what the original post and subsequent poster is looking for, the information he is giving is misleading. I would hate to be the one making a poor decision based on that information, so I was trying to clarify (for the post, not to try and prove him wrong). Tim does have quite a bit of good knowledge but is misguided from time to time (as I have been and probably will do again from time to time).
 
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I'm likely going to put Dynomax bullet race mufflers on my truck or something. I don't drive it on the road anymore and I can hardly hear it.

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i put those mufflers on my 2wd street truck. they sound badass.now i understand why they say the bullets are race only.people tell me it sounds like a dragster when its idling.

i originally hooked them up with turnouts infront of the rear wheels. the resonance at part throttle would hurt your ears it was so bad. extremely loud.

i pulled the floor out of the bed to do some chassis work and turned the exhaust up so it dumped inside the bed. much more tolerable inside the cab. if you want to put them on your trail rig i would run them all the way out to the back bumper.i dont think turndowns would be a wise choice. if they end up being too loud, at least they are only 30bones a pop. i think you'll like em.
 
I have single in, dual out dynomax ultra flows on my 5.9L durango /forums/images/graemlins/peace.gif /forums/images/graemlins/peace.gif. If you like deep exhaust its the way to go. I wouldnt give em up . i havent heard the race muffler but the ultra flow is AWESOME. /forums/images/graemlins/k5.gif
 
i also have a 40 series flow on my 94 blazer and will never be purchasing a flow EVER AGAIN. too expensive for what you get And in the comparison of magnaflow to dynomax ultra flow... THEYRE THE SAME THING. /forums/images/graemlins/thumb.gif /forums/images/graemlins/whistling.gif
 
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I'm likely going to put Dynomax bullet race mufflers on my truck or something. I don't drive it on the road anymore and I can hardly hear it.

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i put those mufflers on my 2wd street truck. they sound badass.now i understand why they say the bullets are race only.people tell me it sounds like a dragster when its idling.

i originally hooked them up with turnouts infront of the rear wheels. the resonance at part throttle would hurt your ears it was so bad. extremely loud.

i pulled the floor out of the bed to do some chassis work and turned the exhaust up so it dumped inside the bed. much more tolerable inside the cab. if you want to put them on your trail rig i would run them all the way out to the back bumper.i dont think turndowns would be a wise choice. if they end up being too loud, at least they are only 30bones a pop. i think you'll like em.

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I like my tailpipes. That's part of the reason that I don't like my flowmasters. Flowmasters sound much better with dumps than tailpipes.

I had 12" long glasspacks for a long time and I didn't think they were too loud, just didn't care for the tone.

I'm not a sissy, I can handle loud. Once I get some time and money to mess with it, I'm going to cut my flowmasters off and throw something different on there.
 
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Completely untrue. If your headers are the proper length and size, all of the scavenging effect that you're going to get will come from them. Everything after that is restriction. I have gone over this time and time again to back it up. Do a search. I have througly beaten this dead horse. Anything you can do to reduce restriction increases power.

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I agree, but off the shelf headers are designed to be used with a collector and "moderate exhaust". Most are "tuned" for a sbc350 (in our case) with a moderate exhaust. A "tuned" header with proper length pipes and proper ID size and proper common chamber volume and length will give the best performance, but not with ones you buy off the shelf (contact any header manufacturer if you don't believe me).

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That is most likely true, but there is no question that the exhaust pipes themselves and mufflers are going to create a restriction that needs to be minimized.

The original question is for true duals without headers. The answer to that question if it wasn't already clear is that manifolds will provide so much restriction that it doesn't even matter what size pipe you use after that.

Also, the megaphone exhaust thing sounds good, but performs horribly.
 
Getting back to the Flowmasters sound vs. performance. I love the sound (not much will compare to it), but from a flow standpoint they are not the best. I have not "flow tested" them, but I have had a few different types of mufflers on my 78 (Flowtech afterburner headers with dual 2.5 pipes straight out the back). I put "Percy's" aluminum collector gaskets in and they last with glasspacks and Summit's cheap turbo mufflers (which aren't the best flowing muffler), but the Flow's are the only ones that cause the aluminum collector gaskets to "balloon" after extended use.
 
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