Hey I have an 86 z28 305 camaro. I had the converter taken off and a glass pack welded in place of it. I was wondering if I should put another glass pack in for the muffler or a flowmaster? Would a flowmaster sound like crap since I have the glass pack in for the converter or what? Also any body know of any good carburetors I can save up for this car, im not wanting anything big like a new engine or anything, thanks for any help you give.

Personlly IMO, if you have emissions testing then put a cat back in.
If your area does not have emissions testing then IMO throw that glasspack in the garbage, along with that muffler and buy a Dynomax UltraFlo muffler, dont waste your money on flowmasters, i've seen flow numbers on them and they flow about 400cfm, while ULtraflo are around 2000cfm. The only thing you buy with flow masters is sound.

Did you read the flow numbers from DynoMax's website?

Flowmasters are a good choice.



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68 Coupe, 350 4-speed
Jim's Camaro Corner (http://www.personal.psu.edu/jxu109/)

I read the numbers on Dynomax's website and was surprised at how low the Flowmaster flow numbers were. However, if the muffler is not restricting exhaust flow in the first place, flow numbers don't mean much.

The only way to tell is to run the car either at the track or on a chassis dyno with the exhaust system hooked up and again with it disconnected at the headers. A properly designed system should not cause a significant reduction in power output.

Based some formulas in a David Vizard article on exhaust systems, my car is fine with a 2 1/2 inch pipe system. Based on engine output, I need 1,300 cfm of exhaust flow. The two 40 Series Flowmasters are good for a combined 1,100 cfm (based on Dynomax's flow data). Thus, my system appears to be restricted. Next time I take it to the dyno, I'm going to run with the headers uncorked and see if there is much of a difference.

If I were you, I would put the cat back on. You are getting NO performance increase from running without it, plus you have violated federal law by operating the vehicle on public roads with it removed. If you insist on not using a cat, put a piece of exhaust pipe that is the same size as the rest of the system in its place and install a good high performance muffler in the stock location out back. Glass packs generally do not flow well and I bet that it is costing you some power.

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Pearl blue & white 69 Camaro with supercharged 350, Tremec TKO, and 3.73 12-bolt

See my website updated 6/10/02 at:

www.geocities.com/gheatly (http://www.geocities.com/gheatly)

Nope, i read it on a website where no one was trying to sell me anything. The flow masters flowed around 400cfm, and dynomax ultraflo out flowed them greatly, i'll get the site later, as i'm on another PC.

Imho, glasspacks will flow better then about anything else if they are the perforated inner core types instead of the sawed or pressed louver type that stick out into the exhaust stream!

A set of glasspacks will perform great BUT they tend to be "cop-callers" b/c of all the rap,rap or "cackle" and back-firing that they allow to get out that creates noise.

I personally love the sound of a set of the cop-callers but you have to run a full "to the rear bumper" exhaust system to get away from the constant noise! I want to put long ones end to end down each side to help cut the noise level and still have the 100 percent straight through exhaust path that they allow. pdq67

PS., and btw,they will change sound and get louder with age as the fiberglass burns out unless you install "steel-packs".

Ahhh, steelpacks. I had them on my 58 Impala.

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Rick Dorion
69 RS Conv,355,M20,4.10's and I don't worry about stone chips ( yet ).

Actually, flow data will tell you that glasspacks are one of the worst flowing mufflers out there. At least according to David Vizard and others. The preforated core has little louvers that stick up and cause a great amount of turbulence, not good. Also, most glasspacks have a 2" core, no matter what size the inlet/outlet is. Also not good. I'm sure there are others that do better, though...

CNC, you are forgetting the main point on what Flowmasters are designed around. Flowmaster mufflers are not designed to produce a mass amount of continuous air flow. They are ment to handle PULSE air flow, like what an engine will produce. This is why the flowbench will say they don't work well, but the dyno and dragstrip ETs say they work great!
Try it, a Flowmaster will keep up with just about any muffler out there!

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1969 Base Camaro
Vortec 355, Perf. RPM, Demon Carb., TH-400
All sheetmetal is NOS GM
See my NEW webpage at: http://www.geocities.com/compuboy007/

I had an 86 Corvette with the cat removed and a straight pipe in its place. Then added 2 flowmasters made for specifically for the car. And man did it sound fantastic I will NEVER go glass pack muffler again. Nothing sounds like chambered mufflers.

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1978 Z28 350 4 speed 3:73's

read this article specifically: http://www.boyleworks.com/ta400/psp/exhaust.html
He does quite a few runs with alot of different types of mufflers including 2 types of flow masters, you'll have to look up the numbers to see which ones they were exactly.
The tests showed dynomax 17749 to be the closest one in MPH to open exhaust, the lowest sound level off all the mufflers, and almost the quickest ET, the quickest being open exhaust of 12.95, with dynomax they got a 13.05, and flows they got a 13.20.

in terms of sound:

I just replaced my manifolds with 2 glasspacks turned down at the axle with 2 of the dynomax ultra flows with coated headers and 2 1/2 mandrel bent pipes all the way out the back.

the ultra flows are actually slightly quiter then glasspacks at idle but really wake up at WOT. however, the sound quality is no comparison, the ulta flows sound awesome. and a few months back they were offering a rebate and I got both for $70 a great deal.

also, the ultra flows are a straight thru design with packing, the inside tube has holes but the walls are smooth unlike most glasspacks, just looking through the muffler you wouldn't believe they would do anything, you can almost reach right through the 13" or so by 2 1/2" dia pipe.

Per Silver69Camaro,
"The preforated core has little louvers that stick up and cause a great amount of turbulence, not good. Also, most glasspacks have a 2" core, no matter what size the inlet/outlet is. Also not good."

The dynomax/Thrush/Walker-Continental perforated core glasspacks are totally smooth inside as well as come in a variety of sizes up to a true 2.5" through core!

If you ever get a chance, hold one up to the light and look throught it and you will see what I mean!

They flow about as well as a straight-though PIPE!!! So you can't get any better then that unless it's a modern equivalent made like a turbo muffler but "y'ed" inside to double the flow capacity! I think both Dynomax and E-brock are selling them made like this.

Check it out if you get a chance. pdq67

All this talk about Flowmasters not flowing had me worried. I searched the web for some results and couldn't find much. I almost ordered a set of Dynomax Ultras just to try out. But I went to Torque Techs site and read what they had to say. Here it is.

"There are many claims about different mufflers being better than
others. Our experience is that the above mentioned Walker's and
Flowmasters are hard to beat. There is NO difference between
them except for maybe sound. Our experience involves both "at-
the-track" tests and dyno tests - we just don't see any difference."

Now I feel a little better. I still might try some Ultras later but for now, UPS just delivered some Canfield 200's. http://www.camaros.net/forum/biggrin.gif Gotta concentrate on them for now. One thing at a time.


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409SB, TH350, 12bolt 4.10
7.18 @ 95 on premium pump gas

[This message has been edited by Hals73RS (edited 07-11-2002).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Green 86 Z28:
Hey I have an 86 z28 305 camaro. I had the converter taken off and a glass pack welded in place of it. I was wondering if I should put another glass pack in for the muffler or a flowmaster? Would a flowmaster sound like crap since I have the glass pack in for the converter or what? Also any body know of any good carburetors I can save up for this car, im not wanting anything big like a new engine or anything, thanks for any help you give. <HR></BLOCKQUOTE>Flo Schmo...Just look at the incredible history and construction of "FLOWMASTERS". I run an aluminized 2-1/4 FLOWMASTER system on my '67 Camaro L-30 and they are superb! Go with the FLOWMASTERS, you will love 'em!

Flo schmo eh? Is that right? Well the ET's on the pontiac seem to think Flow gets them down the track faster.
Not all of like the resonation of them ethier.
My personally choice would be Straighline performance "street" mufflers, i dont want an obnoxious sounding car, but i want it to go!

He, He!!

CNC,

That is half the fun of owning a hi-po street car is the constant rubber-necking around to catch sight of the Cops first so you can take your foot out of it before they hear you coming!!! pdq67

Hehe, i guess your right, but i drive it alot so i dont want to deal with the noise everyday, but i do want it to have a nice sound, and have the power there!
Your right it is half the fun, if this was my sunday cruiser my combo would involve straighline performance "race mufflers" along with 4.88's out back, huge cam, and alot of people holding there ears when i gas it.

I've installed both dynomax & flowmaster cat back systems on many LT1 motors and they are both good.
The dynomax system is louder but the pipes don't hold up as long as flowmasters. The mufflers are stainless steel but the pipes aren't and I've seen them rot out in little more than a year.
The flowmaster system will hold up much better and uses an "H" pipe before the mufflers which gives you a balanced system and a slight horsepower gain, lots of racers do this so there must be something to it. We just got a chasis dyno at my shop but it isn't installed yet so I can't post some real numbers.
It's your call!

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Drew

69' X-11 350, Turbo 350, Factory Air, PS, PB, 12 Bolt (410 gear) & NOT AN SS

why doesnt anyone just get the cut off valves for after the headers, that way you can run a "quiet muffler" on the street and just open them up and scream on the track?? Thats what im thinking about doing so i can drive it everyday then have the benifits of open exahust at the track, what do you all think?

Alot of tracks and classes require mufflers, and alot of cars are actually ET quicker becuase of the extra torque for the exhaust. The best thing is to opyimize your exhaust to give you the best torque with minimal top end restriction.

oh thanks for the info, i was just curious, its seemed practical.