IF you have a Magnaflow Cat-Back kit...

NateRW21

NateRW21

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Can you take some pictures of it installed for me??

I have an 03' and if it isn't too different from the gen II exhaust, I may just modify it to make it work... I'd really appreciate the help!

note: my speculation is the cat-back connects at a bit different spot and obviously the tips are different; if that's it, it shouldn't be too much to get it to work! And I think that would be the sound I've been looking for.
 
Cheaper to buy the muffler and tips that you want and have a local exhaust shop bend/weld up some pipe.

Just my 0.002.
 
yeah but there's no one around here with a mandrel bender... if it's not mandrel bent, I might as well leave it stock.

Could do just the mufflers with the factory pipes... I don't know...
 
I feel that is debatable; non-mandrel bends severely restrict flow; something like up to 40-50% depending on the degree of bend. Plus you have the turbulence of going from a restriction to open, restriction to open over and over again.

No thanks... if it's not mandrel bent; I'm not interested. (when's the last time you saw an aftermarket exhaust company make a cat-back system that was non-mandrel?)
 
Unless you're going forced induction, you will not notice a difference. Even more so on a naturally aspirated small V8 like the 3.9.

The exhaust that was on my '87 was not mandrel bent all the way through and it still put out ~450-ish at the crank. The exhaust on my LS isn't mandrel either. Not worth the extra money to me. If you wanna do it for the coolness factor, by all means go for it.
 
Exhaust difference---Magnaflow cat-back

I wish I could help you, but my exhaust system is behind my belly pan. I am under the impression that the only difference between the '02 and '03 is the downturned tips on the '02 and the through-the-valance shiny tips thereafter. It sounds great, and seems to make a difference, particularly when paired with Ken's (LSK) intake tract.

KenS from Ben's Place
 
Thanks Ken... I was thinking pretty much the same thing. Sound is my issue; magnaflow had said they couldn't do much for performance improvement on the 03-up (although a while back they supposedly had something in the works that was worth 10-15HP... yet they never released it). So I'm not looking to see much of anything for performance gain (hey, if there is a gain... good); I'm really looking for a nice, yet subdued sound. Perhaps I'll give it a shot when it warms up a bit outside!!
 
i have a '00 LS and i was debating on either going magnaflow or buying a flowmaster universal kit and just using some tuner style mufflers (which are just basically resonators) but with some turned down tips so i can tuck them under the car and no one will be the wiser, anyone think that will be a bad idea?...will i lose too much back pressure?...
 
First off, If it was that easy to modify, magnaflow would probably just have done it. Secondly, I had my custom exhaust made on my 03 LS8 so I have seen the ends and outs of the stock system. There is a 3rd cat in our system that works as a balancer pipe (ie. h pipe). If you were to put the magnaflow on you would have to keep the stock crappy cat/hpipe and would again have to put another one on due to the x pipe that magnaflow supplies. That third cat is a horrible design and needs to go if you are wanting to see gains. If you are strictly going for sound then just get some weld-in mufflers and be on your way....

Thirdly, as mentioned above, with such a small displacement V8 I guarantee you will not see ANY difference between crush bent vs. mandrel bent. Just go with 2.5in crush and you will be FINE. Now if you are planning on going forced induction then you need to look at mandrel bent JUST to get the most out of what you have. (I doubt this is your situation.)

I feel that is debatable; non-mandrel bends severely restrict flow; something like up to 40-50% depending on the degree of bend. Plus you have the turbulence of going from a restriction to open, restriction to open over and over again.
No thanks... if it's not mandrel bent; I'm not interested. (when is the last time you saw an after market exhaust company make a cat-back system that was non-mandrel?)
Click to expand...

This is simply relative you what car you have. Yes, a crush bent exhaust is going to DEF hurt you if you are running 600 HP. However, this is not an application where this factors in. As far as the after market goes, Companies as big as Magnaflow create thousands of exhaust systems a year. Its that simple. The paid for that mandrel bender the first 3 months they had that thing.
 
Third cat Bull S***

2102074784_2f9eeab271.jpg


In reality as well, the stock system has some wicked bends that arerent needed. Look at the tail pipes in this.

2101293341_ef7485d62f.jpg
 
WOW... you feel really strong about that third cat huh?

I'm going to go the route of the obvious here, but you're positive that's a third cat and not just some sort of crappy cross-over chamber? I've not looked at the exhaust that much and my manual doesn't reference specific cats or quantity... and the emissions part of the manual only goes up to 02.

I was really looking for something where I knew what sound I'd be getting... the resonators and mufflers were my real interest, not the piping. Maybe I can get some 2" versions of the same resonators and mufflers that come in the kit; I'll have to look into it.
 
NateRW21 said:
WOW... you feel really strong about that third cat huh?

I'm going to go the route of the obvious here, but you're positive that's a third cat and not just some sort of crappy cross-over chamber? I've not looked at the exhaust that much and my manual doesn't reference specific cats or quantity... and the emissions part of the manual only goes up to 02.

I was really looking for something where I knew what sound I'd be getting... the resonators and mufflers were my real interest, not the piping. Maybe I can get some 2" versions of the same resonators and mufflers that come in the kit; I'll have to look into it.
Click to expand...


Yes it is a cat. Its a cat and a crossover built in one.

PLEASE do not get 2inch mufflers. Im telling you that crush bent piping will still be more free flowing then that stock crap.

Look at the stock diameter comparted to the new 2.5 in.

2101294179_10e3ec3b5f.jpg


-- I am done wasting my time trying to explain this for you. MOST everyone who know what they are talking about are going to tell you the same thing I just did. If your not going to take our advise, go buy 2in mufflers and gain 2 HP.
 
Crushed 2.5", at a 90 degree bend decreases the flow by about 20-25%; this is equal to just a hair over the flow over a 2" mandrel bend. So in reality, you aren't getting that much of a flow gain (you will only flow as much as the smallest point). Certainly not enough for me to bother with having pipes bent up and installed.

I'm looking for a suttle muscular sound and given Magnaflow said they couldn't do much to better the factory exhaust as far as performance goes... I have serious doubts what benefit new pipes would have for a pretty much stock gen II LS when you take the "third cat" into consideration (which I highly doubt I'd consider removing). I'd be happy with new mufflers and resonators to give me the sound I want.

As far as Mandrel vs pressure bending... The numbers don't lie; mandrel bending flows better with less turbulence. This is an indisputable fact; if you're happy with your pressure bend pipes, good for you... but that's not good enough for me. If I'm going to do something, it's going to be right and with all available technology... that means if I do pipes, they are mandrel bent and stainless (Galvanized would only last a couple years here in MI, even though carbon steel retains heat better, keeping velocity up).
 
Are you planning on making 90 degree bends??? Its obvious that mandrel flows better, Just not enough for you to notice. Im just trying to save you time, money, and frustration. Take it or leave it.
 
I agree the connection were the cat-back bolts and the tips are the likely only difference keeping you from bolting it on. But having the 3rd cat will change things sound and performance wise compared to the 00-02 cars. The 00-02s don't hve it, why is the 03-06 system supposed to flow better is beyond me. I'm guessing that its the exhaust manifold design itself that was better and not the exhaust itself that was better, and this was confussed somewhere down the line.
 
02LSE96LSC91SE84TC said:
I agree the connection were the cat-back bolts and the tips are the likely only difference keeping you from bolting it on. But having the 3rd cat will change things sound and performance wise compared to the 00-02 cars. The 00-02s don't hve it, why is the 03-06 system supposed to flow better is beyond me. I'm guessing that its the exhaust manifold design itself that was better and not the exhaust itself that was better, and this was confussed somewhere down the line.
Click to expand...


Hmmm... I don't know! Were the manifolds in-fact different??

You make a good point with the third cat changing the sound... what a PITA...
 
02LSE96LSC91SE84TC said:
I agree the connection were the cat-back bolts and the tips are the likely only difference keeping you from bolting it on. But having the 3rd cat will change things sound and performance wise compared to the 00-02 cars. The 00-02s don't hve it, why is the 03-06 system supposed to flow better is beyond me. I'm guessing that its the exhaust manifold design itself that was better and not the exhaust itself that was better, and this was confussed somewhere down the line.
Click to expand...

One thing is high flow CAT's on the 03+.
 
BTW you can buy prebent mandrel pieces in various angles through Summit. So if you must have it you can go custom this way.

I made a pair of over the axle pipes on my 76 CobraII this way. There was no way a bender could fit a pair of 2 1/2" pipes on the SAME SIDE on that thing. Did it with 4 180degree prebent mandrel pieces from Dynomax. Turned out slick.

The diff on a 03up sits more to the drivers side, something else to consider.
 
yup... had to go that route on my truck for my true duals; Bassani Y-pipe w cats and gibson cat back; turned the Y-pipe into an H-pipe, two flowmaster 50D's out the gibson pipes which I changed from side, behind tire exit to exit at rear corners. Used the Gibson muffler along with some 45 degree bends for a cat-back on my father's truck, exiting before pass. side rear tire. Works well enough...
 
That's how NickT does the exhausts on the Mark VIIs over the axle. Orders pre-bent mandrel over axle pipes from Dynomax.
 
Exhaust manifolds

I am handicapped by never having seen the exhaust manifolds of a 3.9. However, the 4 litre Jag engine that's being built as a replacement engine for my '02 has manifolds that seem to have exits in the same location as the original engine. (I have a Magnaflow system on mine and could see the cat lay-out as I installed it.) The intake manifold runners on the Jag seem to be larger than the ones on my '02 so it makes a certain amount of sense that the exhaust may be larger as well. They assuredly aren't as free-flowing as a set of custom headers would be, but the gain, for my turbo set-up---see my thread in the HP section---would be slight enough as to be not worthwhile.
KenS from Ben's Place
 
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