[mech]

I went to Grand Muffler in Marrietta, GA they come highly reccomeneded. They quoted me $600 for a full 2.5" mandrel bent maganaflow exhaust with a magnaflow cat, resonator, muffler and tip. What do you guys think?



Its pretty tempting....

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[flash]

this is somethign very high on my list - i already have worked out one system that seems to work, but this hs not met with the desires of everyone



in tandem with the roll bar, is the development and testing of a new exhaust system - it will include a high-flow cat taht is assured to fire off, thereby meeting smog test and emissions needs, a resonator, a muffler, and an oval tip - the entire system will be stainless and complete - it will require removing the factory cat and welding a flange - it will be a deep throaty sounds, about 4 db louder than stock, measured C weighted at 6 ft - we are also considering a cat-back, but anticipate less power gains from that system



should be done in about 2 weeks



anticipated retail at about $800



i'll give you more details on friday

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[968Z]

$600??? Was that an installed price? Marietta is close by, and that would be very tempting! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

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[mech]

[quote name='968Z' date='May 10 2005, 10:50 PM']$600???  Was that an installed price?  Marietta is close by, and that would be very tempting! <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" />

[right][post="4611"]<{POST_SNAPBACK}>[/post][/right][/quote]



Yes, that was installed... Its not hard to find, they were nice.

Grand Mufflers Of Georgia.

1607 S Cobb Dr SE.

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[flash]

yeah - my current system was just over 500 - i'm happy with it, and there is defintely a great tone and a bit of high mid improvement, but i can tell there is a bit of turbulence that is changing the curve in a couple of spots - i think we can do even better



my header design guy thinks there is another 5 horspower and a couple of pounds of torque to be had though with the full cat system - we'll get started on it on thursday and see what we end up with

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[Cloud9...68]

[quote name='flash' date='May 11 2005, 10:11 AM']my header design guy thinks there is another 5 horspower and a couple of pounds of torque to be had though with the full cat system - we'll get started on it on thursday and see what we end up with

[right][post="4627"]<{POST_SNAPBACK}>[/post][/right][/quote]



Can't wait to see what comes of this. Will the results be covered in 9 Magazine, or directly through this forum? Thanks

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[flash]

not sure yet - depends on how dramatic an improvement it makes - maybe both

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[mech]

Hey guys, this project is going ok.



The new tip looks great, it almost looks like it was supposed to come that way, I'll post pics soon. The first incarnation of the exhaust system was looouuuuud! it was a full header back exhaust with magnaflow components and 2.5 inch piping. The grand total was $360 for G&S mufflers in Kennesaw. They did a good job, on this flip side I wasn't happy, the performance loss. So now we are on the 2nd gen. with a much larger resonator, the sound is almost perfect, the exhaust is deep with a little gurgle. The 2nd fee was $50.



With the windows down it is louder than stock, Ill get a recording. There was a gain in some of the lost power, but Im still not totally satisfied. This weekend I may have them place some kind of 2.5 in to 2.25 inch restrictor or a more restrictive resonator to gain some more back pressure. What do you guys think I should try next, I think I can get this system semi-close to how the stock preformed.



I'm tempted to try to chip the car now, but I'm not sure if that is a smart lab procedure(too many variables) although the chip and new exhaust may work well together.



stay chill

-v

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[flash]

this trial and error thing is exactly why i ended up doing what i am - i knew ahead of time that the magnaflow wouldn't work - flowmaster had the same problem - not enough restriction to create the necessary backpressure - that's how i ended up with the sebring



the next incarnation will be a hi-flow cat with resonator built in and i'll try a perf resonator instead of a venturi type - i have a suspicion that the venturis are creating a bit of turbulence - the bottom end is good, but the mid seems to have a slower response than it could have - i don;t want to reduce the backpressure any more though, so the cat with a resonator should add back what the perf resonator decreases



testing should be next week

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[Greimann]

What you guys need is one of these mufflers with adjustable backpressure.





http://www.powereffects.com/

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[rosssurf]

[quote name='Greimann' date='May 18 2005, 02:52 PM']What you guys need is one of these mufflers with adjustable backpressure.





http://www.powereffects.com/

[right][post="4871"]<{POST_SNAPBACK}>[/post][/right][/quote]

Now thats an interesting but ugly looking idea. I'd like to know more about it. I checked the web sight and it is not yet complete.

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[Cloud9...68]

[quote name='Greimann' date='May 18 2005, 12:52 PM']What you guys need is one of these mufflers with adjustable backpressure.





http://www.powereffects.com/

[right][post="4871"]<{POST_SNAPBACK}>[/post][/right][/quote]



Since the ideal backpressure depends on driving conditions (rpm, throttle position, etc.), it would sure be slick if a system like this one could be integrated into the engine control system, allowing backpressure to be optimized for all conditions. I know the new Z06 has something like this, and I think other cars in the past have had cruder variations of adjustable backpressure. I know, this is just another dream, given the very low volume of our cars, but it would be great if somebody within the 968 community with the appropriate expertise would take something like this on...

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[flash]

hmmm - that gives me an idea............

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[Cloud9...68]

[quote name='flash' date='May 19 2005, 06:25 PM']hmmm - that gives me an idea............

[right][post="4907"]<{POST_SNAPBACK}>[/post][/right][/quote]

Does it have anything to do with occum's razor (I thought I saw one at Autozone today <img src="/forum/images/smilies/968/wink.gif" class="smilie" alt="" /> ?

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[mech]

Has anyone measured the pressure of the stock exhaust system, that would help me a ton in determining how to proceed with adding some backpressure. '





The variable system picture above is pretty cool thanks for the link Greimann.

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[Larry Currie]

I paid over $600 for my B&B and then had to pay for installation. <img src="/forum/images/smilies/968/mad.gif" class="smilie" alt="" />

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[earossi]

[quote name='flash' date='May 11 2005, 11:11 AM']yeah - my current system was just over 500 - i'm happy with it, and there is defintely a great tone and a bit of high mid improvement, but i can tell there is a bit of turbulence that is changing the curve in a couple of spots - i think we can do even better



my header design guy thinks there is another 5 horspower and a couple of pounds of torque to be had though with the full cat system - we'll get started on it on thursday and see what we end up with

[right][post="4627"]<{POST_SNAPBACK}>[/post][/right][/quote]





Flash,



I have a conundrum. I want to replace the exhaust on my 93 cab in the worst way. Since the car has the original cat and exhaust at 80k miles, and I don't like the sound, I've been reading all the posts on this forum trying to decide what to do......store bought or custom? Since the store bought is pretty much confined to either OEM or the B&B, I would opt for the B&B if I go that way.



I have also investigated a custom exhaust done locally here in Chicago. Pricing is in line with what other posters have quoted......between $400 and $500 for a cat back installed; however, I have the same concern you all express......the back pressure imbalance that results in either flat spots or a loss in low end power. Since I mostly street this car and it is a daily driver, I don't want to give anything away in low end torque or driveability. In fact, I would like to increase the low end torque, if possible. And, flat spots are disconcerting and annoying.



Which brings me to the dilemma you have just created for me. I like the way that you approach projects, and would be happy to be first in line for the full exhaust system you are considering when you are happy that it is ready to go. BUT, I also know that you have a lot of other projects on your calendar, and so wonder if the exhaust is enough of a priority for you to work it out in the next month or so......or as some of the other posters chuckle......"for Flash 2 weeks means 3 years!".



I can wait two months...........but not 3 years!



Your comments and advice would be appreciated.



Regards,



Ernie Rossi

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[flash]

i am only interested in a street system - that's why we aren't going after an equal length tube header - we don't want to lose the low end - low end is the priority, but i don't want to sacrifice top end either - i'm pretty close now, but have a couple of things to work out



it is very hot on my list - i will be wrapping up the roll bar project as soon as i get back from cancun on the 8th - then i'm onto the exhaust - since it is the same shop, and they need to finish the first batch of roll bars, it is possible i won't get a prototype built until the end of the month



i will have done flow testing on the OEM system and my current system by then, as well as the B&B



the moment it is done, i will set up dyno time where we can test each one on the same car on the same day on the same dyno



i would guess you can expect completion around the 15th of july, with availability (on the presumption it works) immediately thereafter - price should be about 800 with cat - if we find that the system works better with the factory cat, it will likely be about 650



if this turns out to be a full cat system, there will be a flange that needs to be welded where your cat gets cut off, so you can expect to have to pay an exhaust shop 50 bucks to poke the system in there

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[RS Barn]

Flash,

I have a different view on exhaust.

I developed a header/exhaust system to increase hp/tq across the board. I worked with a header design/mfg and a notable Porsche engine guru. Our equal legnth header does increase hp/tq across the board. Although the results were not as dramatic as we envisioned, the header was the launching pad for other performance gains.

The header/exhaust with cold air intake and custom chip developed a huge increase in torque form 2000-3500 and a very consistent increase from there to 7000rpm. Two to three times what a chip alone could muster. We did not receive the same results without a header. The header is clearly a launching pad for other mods. Exhaust mods alone can have more detriment than good.

I originally developed this as a system, I have found many 968 owners already have some sort of cat back system. I am working on a way to incorporate my header and cat with B&B etc.

I will have my Polar Silver 968 at the 968 celebration for test rides.

Pete

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