[David Burke]

Well I did it...I went ahead and spent $2K on a Larini system (rear mufflers only) for my '02 CC. Put them on a few days ago and have had mixed feelings about them. On one hand, I didn't expect them to be so much louder than the stock set-up, (although they're really quiet)...and on the other hand, holy sh_t...the sound that comes out of those pipes!! (kinda like a big block F430)
I must say that it's taking me some getting used to having so much noise (sorry, sound) coming from the car, but what 's really bugging me is that the car seems slightly less 'snappy' throughout the entire RPM range in the acceleration department.
I've read elsewhere on this forum that a decrease in back pressure can result in a loss of low end power, and I feel that's what's happening in this case.

By the way, before installing them on my car (an easy, 45 min. bolt on job)
I noticed that the're almost 100% copies of the Tubi mufflers although with slightly larger end pipes.
The reason I'm bringing this up, is that the common belief is that these types of mufflers add HP not decrease it.

In any case, could anyone who may have put Larinis on their Coupe let me know what their experience has been? I'd appreciate the feedback.
Thanks!

[SJP63]

Hi David

I put Larini's on my 04 Coupe about 2 months ago. At first they sounded great - not too loud and only at high revs. Then over time I became aware of a deep booming noise under any sort of load below 3000 rpm. Even pulling away the boom was there, disappearing above 3000.

I had to take them off in the end. All Larini said was check the rest of your stock system for leaks.

Shame as when they were first fitted im sure it didnt sound like that.

As for power - I didnt notice either way

[GCalo]

Originally Posted by David Burke

---I've read elsewhere on this forum that a decrease in back pressure can result in a loss of low end power, and I feel that's what's happening in this case.

That's a bit ridiculous.

If you are feeling a reduction in performance it's directly related to that muffler's design.

Free flow mufflers should enhance performance and not degrade it. I speak from years of first hand design experience on this subject!

Frequently designs try to achive a specific sound level rather than design for maximum efficiency. This will include internal restrictions to achieve that sound.

Proper design should always be for performance.

[pganmol]

Originally Posted by GCalo

That's a bit ridiculous.

If you are feeling a reduction in performance it's directly related to that muffler's design.

Free flow mufflers should enhance performance and not degrade it. I speak from years of first hand design experience on this subject!

Frequently designs try to achive a specific sound level rather than design for maximum efficiency. This will include internal restrictions to achieve that sound.

Proper design should always be for performance.

Free flow does not mean it increase performance all the time. It is true that free flow muffler will lost a bit of low end but it will gain more at the high end. This is the nature, cannot change it. If you want both end performance increase, you have to have active exhaust system that have the right back pressure for the low rpm then by pass to the free flow at high rpm.
pganmol

[GCalo]

If this were in fact the case you'd see other than straight pipes on Indy cars and F1 cars.

Any exhaust restriction limits performance whether low or high end.

[MaseratiBoy]

Originally Posted by GCalo

If this were in fact the case you'd see other than straight pipes on Indy cars and F1 cars.

Any exhaust restriction limits performance whether low or high end.

actually, pganmol is completely right.

free flow does NOT mean increased power all the time...

ie, xpipes give a big boost compared to not.

The logic of f1 cars wouldnt use straights unless they were the best is liek saying that since f1s use RWD, AWD isnt as good for performance cars.

[M!]

Originally Posted by GCalo

If this were in fact the case you'd see other than straight pipes on Indy cars and F1 cars.

Any exhaust restriction limits performance whether low or high end.

how often do Indy or F1 cars run at low rpm?

[RickBullotta]

Out of curiosity, did you reset the ECU? Anytime you make a change that could affect the engine's calibration (new fuel, air filter, exhaust system or other engine changes), it would seem a good idea to allow the ECU to recalibrate itself to the new conditions.

[Aeroresh]

Originally Posted by RickBullotta

Out of curiosity, did you reset the ECU? Anytime you make a change that could affect the engine's calibration (new fuel, air filter, exhaust system or other engine changes), it would seem a good idea to allow the ECU to recalibrate itself to the new conditions.

Agreed. When I installed my straight through rear pipes I too noticed a decrese in power and the gearshifts were alot slower than before.

It took a few hundred miles for things to settle down and it now feels a fair bit quicker than stock