need a few more exhaust details

[solowookie]

OK I put an exhaust in my k5 about 3 months back, and I gotta another one coming that will be my family travel vehicle. the first K5 is way too load for a family driver so I want this one designed differently. I also want it to be built more around torque.

I'm wondering how headers affect the performance / sound volumn. I'm considering thorleys, but I'm wondering what the best performance / quiet setup would be. maybe some shorties???

what about a dual vs. single exhaust??? which is quieter? and how is the performance difference between a dual and single???

I'll definately be removing the cat. I'd like to go with headers that will meet emissions (even though I have none here), but I will be disconnecting the smog pump.

so far I'm caught between going with flow master 70 series mufflers and dynaflow. any other suggestions???

<font color=blue> Jeff </font color=blue>

 

[Chris Demartini]

<font color=blue>about 2 years ago when I put my new motor in, I put in full-length headers at the same time. It wasnt that much louder but it sounded better. Billybob on this board just put JBA shorties on his new 84 and its quiet inside (replacement mufler and single pipes). Single will definetly be quieter. Go with a 3" exhaust and a Flowmaster 50 series, that should be quiet enough but still sound good and make power.</font color=blue>

 

[CaptCrunch]

well headers add volume almost always... I personally for your daily driver truck would stick w/ stock manifolds for underhood temps, ease of spark plug removal, and sealing. Run 2 1/4" true duals. In terms of muffs the Flowmaster 70's are pretty tame and the 50's are a bit louder w/out the blarring of the 40's. Also I think the Dynomax or thrush turbo muffs are pretty decent... about the 50 series level... mostly get volume when you nail it, but add a tiny bit to idle. Also may want to look into the 3" gibson singles... Mine sounds nice... is kinda rusted out, but I guess it has been on there for like 100k of the trucks 145k life... so not too bad for here in the midwest

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<A target="_blank" HREF=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</A>

 

[jarheadk5]

If you're disconnecting the smog pump, there's no reason that I can think of for buying emissions-legal headers. This probably depends on the manufacturer, but I believe what makes a header emissions-legal is the fittings for the AIR (AIR-Air Injection something-or-other) and the testing it went through. Why pay extra for the CARB E.O. number and the AIR fittings when you won't be using them? If I recall correctly, the non-emissions-legal Thorleys are like $100 cheaper than the legal ones.


If at first you don't succeed, failure may be your style...

<font color=green>Semper Maintenance!<font color=black>

 

[pregate]

i donno about your local laws.. but here in texas its illegal to take the cat out of any car built with one. even if you no longer have to pass the emissions test, they still make sure all the parts are there..

1979 K5 Blazer
4x4, 350 V8

 

[solowookie]

I'm sitting here looking at the prices in summit racing and I'm only seeing like a $10.00 difference. if they were $100 diff then it would be worth not hooking it back up.

If I change headers I'd want to keep the air injection because it would be pretty easy to hook the belt back up, and add a cat if I eventually sold it somewhere they had emmisions.

<font color=blue> Jeff </font color=blue>

 

[solowookie]

I live in Wyoming... (nuff said???)

<font color=blue> Jeff </font color=blue>

 

[solowookie]

I've heard pretty good things about the gibson systems... I'd really like to do a different header, but if I do I'd almost definately have to go with the thorleys, or nothing.

I need to talk with the guy over at the muffler shop about headers etc, but right now I'm thinking more and more about 70 series. I'll probably change my current one over to 50 series flow masters.

<font color=blue> Jeff </font color=blue>

 

[Thunder]

I'm running Edelbrock headers into a single 3" mandrel bent exahust and a flowmaster 70 series muffler no cat. It is a great set up for a daly driver. Gives great power and torque. Is quiet at idle but lets you know you are running a flowmaster when you romp on it. I also get better gas mpg on the freeway.

<font color=orange>GOT HORSEPOWER?</font color=orange>

 

[Smitty]

I just had a new system put on last week. Went with 3" from the front of the cat to the tail pipe. Asked for a 50 series Flowmaster but the put a 40 series on by mistake. I'm going to change it out later because it's too loud heading down the road.

They also put the new cat on upside down (says "top" on the bottom). The only reason that I can think of for specific positioning would be the heat shield. I ran it through smog and it passed with flying colors. Does anyone know if it will cause any damage to the cat if it's mounted upside down???

Smitty

 

[solowookie]

I was thinking of the flow master 70 series, but I think I'm going to do the gibson cat back system. I also think I am going to swap out my 40 series flow masters on the current rig I have to 2 24" gibsons. (I almost did 70 series flow masters on it too).

I will probably do the 2 gibsons on the current one I got first to measre how I like it.

<font color=blue> Jeff </font color=blue>

 

[dyeager535]

As others said, emissions legal=AIR injection ports on teh headers, and perhaps the O2 bung, which, depending on year, you might need.

Word of caution about the AIR pump...if you disconnect it, more than likely (75% or so? hehe) you are going to end up replacing it. Without use, tehy seem to "freeze up" pretty regularly to anyone that has done this, and require replacement. Not sure what they cost, but to me it would be an either or situation. Either run no emissions, or buy the smog legal headers and run all emissions. The AIR pump costs virtually no horsepower.

On the mufflers, I will say that I had "California Turbo" dual Thrush mufflers on my '83 with 305, and it sounded kinda funny. i didn't really like the sound when I was revving the engine up, like getting on the freeway. To tell you the truth, i really like the GM mufflers I have on it now that are off a 6.2 litre diesel blazer. Pretty quiet, a little bit of a deep tone to them, and they are duals, and made to fit under our trucks.

Just my opinion.

Dorian
My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
No anti-theft measures on your truck? No pity when its stolen

 

[84_Chevy_K10]

Mufflers are what detirmine your sound. Yes, headers will make it louder, but if you use quieter mufflers you've got nothing to worry about.

The best exhaust system would be 1 1/2" headers, 2 1/4" pipe with an X crossover if possible, place the mufflers as far back in the system as you can get it, (less volume=better flow and less noise) and let the tailpipes exit wherever you choose. Choose some non-restrictive type mufflers if you can.

Contrary to popular belief, Flowmasters and other chambered mufflers are quite restrictive. Straight through mufflers are your best bet. Borla and Dynomax make good ones. If you get some with a bigger case, they'll probably be more than quiet enough for your taste.

I like them LOUD, so I have Dynomax Jet-Hot coated headers, 2 1/4" pipe, 12" long glasspack mufflers, and side exit tailpipes (more echo). I love it, but I'd bet that you guys would consider it very loud. It's louder than any truck with manifold straight pipes.

Tim
'84 Chevy K10, lifted, loud, fast, and 3/4 ton axles