I was wondering if someone could help me out. I have a 1989 Firebird with a 2.8 in it.

I finaly have some cash to spend on getting some exhaust for it, I've stopped at a muffler shop...and they seem to not know much about firebirds/camaros.

One: Where can I get good headers that will allow me to still run legaly and have a cat back system?

Two: What kind of cat back system should I get?

Muffler: What is the best Flowmaster or Dynamax muffler for the 2.8?


If anyone answers these questions I will be in your debt!

PS: I've looked at Monroe Muffler and they added up a cost for a cat back pipe for about 160 bucks.....sounds like a big price to pay....


Thanks Fellas!

Dan
icepack212@hotmail.com

 

Go here for the headers https://www.thirdgen.org/techbb2/sho...hreadid=160965

I would suggest a dynomax catback the part# is 17493 at summitracing.com but if you want some thing louder I would go with flowmaster 80 series muffler.

 

Thx for the info guys, I guess headers are not worth it for a 2.8, I think i'll stick with a cat back system. I got a quote from a flowmaster dealer: $399 for a flowmaster cat back system (2.5 inch diameter pipes running from a cat converter to a muffler that runs out 3 inch dual pipes, each pipe splitting into a dual, thus a quad all together) This cat back system is designed for a 305/350, but with some modification to the cat converter hook up, I was told I could have it hooked up!

What do you think?

Dan
icepack212@hotmail.com

 

Dynomax all the way baby...

 

I'm geting a dynomax catback with a cut-out as soon as I finish my port job and maybe some headers.

 

Whats the difference in Dynomax and Flowmaster? I"m looking for some boost in HP, and some nice sound would be nice also!

 

One more question: Will a Cat back system from a 4th gen Firebird/Camaro work on my 3rd gen?

Thanks!

 

the exhaust tone & cost. not sure how much $$ difference there is between individual mufflers.

 

Would you recommend one over the other?

 

Dynomax = less aggressive tone
Flowmaster = aggressive tone
It depends on you, what kind of tone do you want? Both will give you the same amount of HP. But I would say Dynomax

 

Awesome, thanks!


Any word on whether a 4th gen firebird/camaro cat back system will fit on my 3rd gen??

 

they have a different I-pipe, but I believe the muffler & tail pipes will fit

 

Which part is the I-pipe?

 

intermediate pipe - runs from teh cat to the muffler in the back. The long pipe under the center of the car

 

A friend of mine had a 4th gen WS6 firebird muffler on his 89 RS V6. It sounded good and he said he noticed a difference.

 

Thanks. I know the Y-pipe is actually shaped like a Y, but I couldn't figure out how someone could think that one of the pipes looked like an I.

 

I am wondering if this setup right here will fit on my 89 2.8:

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2414310200



Please let me know, Thanks!

Dan

 

No that's off a 4th gen, like the others say the I pipe is different.

 

Ok thx, I guess what I'll do is get the dual pipes and muffler off a 4th gen but get the I pipe fabricated for my car.....would a 3" diameter be possible to do with my stock cat converter?

 

NO! 3" exhaust is a bad idea, our 6's need back pressure, I think you would have to be pushing 200-250 HP to get a 3" exhaust. Trust me with my open exhaust... it gives more power at the upper RMP's but decreases torque I only like it for the sound

 

Would 2.5" be good?

 

Yeah 2.5" is good but, for me it's going to be 2 1/2"

 

dont get the Dynomax cat back, the muffler that comes with it (Super Turbo) sucks. Its way to quiet, quieter than stock. But the tone is Okay. (You cant really hear it anyways because its too quiet.)

Plus its a major pain in the *** to install because of thier hanger design. Go wil flowmaster if you want nice sounding exasut.

 

Quieter than stock?! Sweet!!!!!!!! I know who I'm going with for exhaust =)

Err.. wait.. question. is the 3" version still quieter than stock, or am I going to end up having to run a pair of 3" super-stock-quiet-as-hell mufflers?

 

The super turbo muffler is quiet? Hm, news to me. Are you comparing sound to a v8 car? I put the Dynomax on when my stock muffler got a hole in it. After I started the car, I thought I forgot to connect a pipe- the car was just as loud with the dynomax as it was with my original-muffler-with-a-hole.

 

Back to the drawing board for the ultimate in quiet exhaust...

 

The dynomax ARE some of the 'quietest' (dB level), but they have a nice deep tone, that you 'hear' as louder.

If you want silence, I'd say stock, with 2 1/4" pipes.

 

Mellow Tone

 

The Super Turbo IS louder than stock, but it is primarily deeper...and it is not MUCH louder than stock. I was surprised at how quiet it was after the system was installed. It's hard to find a 'sleeper' muffler, because the general philosophy is, 'if you've got a performance muffler, you probably have a performance car, and you want to show that off'....

 

Well, let's see.. I'm going from 275 cfm max intake flow to about 350 cfm.. plus the turbo I have is being restricted heavily by the exhaust side already... getting ahold of a #8 turbine housing will cause that number to grow to 375-400 cfm.. and all of this is without pondering thermal expansion of the air plus the increased volume of exhaust gas... 2 1/4" just isn't going to do it

 

Yeah.. it's unfortunate like that, which is why I'm seriously considering terminating the exhaust with a Y pipe going off to a pair of dead-quiet stock-type mufflers off a station wagon or some such noiseless vehicle. I'm just still looking for something that will flow better and fit better under the vehicle at the same time..

 

No, we don't need backpressure. That's why we put higher-flow mufflers and headers on- to REDUCE backpressure.

 

TomP is correct. This 'lack of torque' you guys are feeling, is the power band being shifted up slightly into RPM band.

Trust me - it's shifted up, and increased.

 

So your saying I should keep my open exhaust and have no torque? I would think we would need some backpressure for that little problem but, if you say so Tom

 

Alright, I'm still a little confused.... But I know Tom knows alot.

 

LOL.... Yeah, TomP = V6 ***?

Seriously... the low end torque is increased in the upper end rpm torque (more hp).

You want to know if it works? I dropped .4 seconds getting rid of the stock cat, and putting a pipe in its place.

 

*sigh* Backpressure is bad. Period. What exhaust is there for is a scavenge effect. As an exhaust pulse leaves the head it has velocity and momentum, and behind that pulse is a vacuum. The idea is to tune an exhaust at multiple levels to make sure that vacuum is there to help pull the next pulse out of the cylinder, through the head, through the header primaries (if you have log manifolds, the physics end there), through the collector, through the exhaust system, and out the tailpipe. With log manifolds, tuning the scavenge effect is pretty much a moot point, but there still needs to *be* a scavenge effect. Backpressure destroys the pulse timing completely, since the pulse gets stopped.

Also, 5 ft-lbs of torque is more power at 3000 rpm than at 2000 rpm. torque*rpm/5252=horsepower

EDIT ---
I figure I need to expand on this real quick. If a pipe is too big, the exhaust pulse loses its velocity too quickly and the vacuum behind the pulse dissapates rapidly, thus also killing the scavenge. See venturi theory (high pressure/low velocity, low pressure/high velocity

 

Since almost no one has headers, scavenging is a moot point, like you said. So instead, just open and run as close to free-flow as possible.

Now, that said, you don't want TOO big a pipe! As the air travels down the exhaust pipe, it'll cool. What does are do when it cools? Condenses, and slows velocity. If it slows enough, you will create a 'wall' of air that your engine now has to fight to get the air out. Best bet - a well tuned exhaust, or go open exhaust.

 

I'd have to agree that cooling would have some effect also, since as the exhaust gas expands in a pipe which is too big, it will tend to cool, just compounding the problem

 

Yep... I've got extremely free-flowing exhaust on my 5.0....equal-length shorty headers, 2 1/2 in mandrel bent stainless steel pipes, a very high-flowing X pipe, and two Flowmaster 40's, open mufflers...no tailpipes or turndowns. The car makes ZERO power from 0-3000 rpms. It's only average up til then. 3000-3500, the powerband comes on so strongly it'll shift you back in your seat some days. Enough torque to roast the ZHP-01 245's for a good several seconds but not enough to get the car really moving quick. BUT, my car, with an aftermarket upper/lower intake and the full exhaust, breathes and pulls to over 6500 rpms..in a V8!!!..verified by my psychotic self. Never have your auto manually held in first gear, and talk on a cell phone when it rings.... You forget to shift.

 

Makes sense to me.
Backpressure = bad
Cool exhaust = bad

But I knew there was a reason to big was bad.

 

Well Ive decided to get a cat back system that has a Flowmaster Delta 80 hooked up to it (2.5" setup) cant wait to put that baby on!

 

run a bullet muffler right after the cat, for the tail pipes, add resonators with some suppertrapps tunned for quiet. that should be quiet enough for ya, and add about 100lbs tothe car