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Discussion Starter #1
Thinking about getting my exhaust modded. Can't afford Tubi but the stock exhaust note is BORING. I'm NOT an exhaust guy so I'm asking for opinions from the experts.

Don't want straight pipes because they're just too loud for the car (IMHO). The question is.. has anyone removed the "Central Silencer" (the muffler in the center just beind the X-Pipe) but left the tail pipe boxes (resonators or mufflers?)? Do the tail pipe boxes lower the volume any? Change the note?
 

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What is everyone defining as straight pipes? No rear mufflers? No center resonator? No X Pipe? None of these?

Not an exhaust guy either. In pursuit of a Tubi like exhaust sound as well, without the 5K price tag, I removed the rear mufflers and the exhaust is certainly louder(too loud I think) and deeper, but not where I want it.

I am also interested in what others have done to the center section of the exhaust. I'm hoping to quiet the exhaust a little and get a sharper note closer to the Tubi. I am thinking keep the X pipe; some research tells me this is better for performance and has little to no effect on sound. Then replace the center resonator with either a dual inlet/dual outlet muffler, e.g. http://www.magnaflow.com/02product/shopexd.asp?zone=main&id=645

Thoughts, objections?
 

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I've seen plenty of these exhaust threads too, and I was wondering the same thing. I consider straight pipes to be one constant tube from the manifold back with no cats, resonators or mufflers. Cat-Back straight pipes, cat-back straight pipes with resonators, with mufflers, test-pipes vs cat's, plus different tube diameters...

We should make a database or something of what people have done.
 

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Discussion Starter #4
The straight pipes I had done to the Viper were from the CAT's back. I don't think you can pass emissions testing with the CAT's removed. Also, the thermocouples would be disconnected from the computer.

My mod consisted of straight pipes on each side with a crossover about mid way. The pipes went straight out to tips. On a large displacement motor with a low redline, the low frequency exhaust note sounded mean but it would rattle glass break detectors, set off car alarms and backfire loudly on deceleration. The Maserati deserves the beautiful higher pitched note of the Ferrari's. The question is, how to get there without Tubi.

Buzz
 

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Mine is done now. Tried about 4 combos today and stayed with the straight pipes from the cats back and added 2 12 inch glasspaks. I also tried a twisty (sound got quieter and deeper) then two 16 inch glasspaks (sounds was probably what you are looking for... quiter than the 12inch ones and cleaned it up considerably.) The difference between my plain cat-back pipes and the addition of the 12 inch paks was measureable for sure. Still get the great sound but cut it down a couple notches and cleaned it up.... say from a 10 to about an 8 or an 8.5. Now I can hear much better in the cabin and didnt lose that exotic sound outside. I know it is quieter because I only set off 1 alarm in my garage instead of the usual 4 and had a late lunch with my roads engineer in Plano and we could speak to each other easily and hear people on the phone no problem. You can even get longer paks if you want to make it quieter yet. All for less than $500 bones. Call Daniel or Jerry at Jerry's. I told them you have the same car and looking for more sound. They were great. Daniel did the install in about 2.5 hours on the total deal both visits.
You should have stopped by and heard all the combos... or just get ya a Tubi and start eating lunch off the
valu-menu:rolleyes:

Just taking the X pipe out will make a big difference and taking just the tail pipes off will also.... we tried all the combos but I wanted more sound and a little more higher pitched note... now I have it.

Combos I tried:

1. Stock
-Sucked

2. Just removed X pipe
- Better but still too low. Sounded like an over revving Camaro

3. Back Boxes off
- About the same as the X removed. Camro again

4.Straight Pipes back from the CATS and 3.5 inch tips
- Sound was awesome but a but too radical and a bit obnoxious after two weeks of driving it that way. The exhaust note exterior and interior sounded great but a bit too much.

5. Straight pipes and 16 inch paks.
- Sounded great but I liked the 12s better

6. Straight pipes with 16 inch "twistys"
- Sound got deeper and quieter. I wanted a higher pitch.

7. Went with Straight pipes and 12 inch paks.
- Sounded like a cleaned up and toned down version of just straight pipes. The paks made it a tad quieter, a tad snappier and a tad higher pitched. PERFECT for me.
 

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The Maserati deserves the beautiful higher pitched note of the Ferrari's. The question is, how to get there without Tubi.

Exactly :)

So to be clear Masher, you removed the X Pipe in your final configuration? From what I have read in general applications it has little effect on sound, and removing it can limit performance.

From front to back: you have both sets of factory CATS, X-Pipe, 12" glass packs, stainless tubing straight to dual 3.5" tips (4 total) Also, what type of tips did you use? I have seen tips that have internal perforation in them like a mini glasspack.
 

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Just read this online, this would seems to explain our system's stock setup a bit (the large center resonator AND rear muffler boxes), but I am by no means an expert. Do we have any exhaust experts out there that can comment specifically on the performance impact of the different exhaust setups people are taking?

"...Open chambered mufflers such as Flowmasters often appear to the pressure wave much the same as the end of the pipe. This means the pressure waves see no change in length and reflection occurs largely as it did prior to the fitment of the muffler.

A glass pack muffler can act significantly different. It does not appear as a pipe end but as a substantial increase in collector length. Result: a reduction of power even though there is no measurable backpressure involved. From this we can see that many comparative muffler tests were in fact “pseudo pipe-length” tests. Although many invalid conclusions were drawn, these tests still demonstrated some important facts. The most important is that the engine's needs in terms of flow and pressure wave length tuning must be isolated, one from the other. This is easy to do by means of the pressure wave termination box (resonator box) mentioned earlier. Incorporating a resonator box into a system produces a layout along the lines seen in Fig. 9. With enough volume, the resonator box makes everything down stream appear invisible to the header's primary- and secondary-tuned lengths. With a flow capability of 2.2 cfm or more, the muffler appears virtually invisible from a flow standpoint. As a result, we have a muffled system that produces virtually the same power as an open exhaust."
 

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The best combination we've come up with for Sound, Performance and Price ( although not necessarily for a legal application <disclaimer> Track Only </disclaimer> ) is leaving the X-Pipe for performance reasons and running straight pipes all the way back from there. i.e. no mufflers and no resonators.

You will still keep all your factory O2 and Thermocouplers sensors.

I do believe that by removing the mufflers completely it may cost you a few ponies. The best of all worlds may be to use a high flow muffler in the rear, it should still be less restrictive than stock.

The sound is excellent and the TUBI to me doesn't sound that much better although it is an improvement. If cost is no issue, I would get the TUBI!

I do believe that Kevin at MVP is working on a more affordable setup as well. Perhaps you may want to go for the above combo to start and then see what his offerings are before you shell out all that money for the $TUBI$
 

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Yep, maybe a good combo would be

a) replace the stock muffs with high-flow ones at the back (maybe the race series from Magnaflow would do; you need to make custom mounts, but nothing a specialized shop would not be able to do...) plus

b) double wall, straight-cut 3.5" polished stainless oval tips (again from Magnaflow; see part #35170)

whilst keeping everything else in place. Unless you want to replace mid-pipe sections with stainless.

BTW Bee, fancy looking at some circuitry (got it from Italy) to connect to the NIT to hook-on aftermarket DVD/NAV/etc using the OEM screen?

Ed
 

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cardiffGiant said:
The Maserati deserves the beautiful higher pitched note of the Ferrari's. The question is, how to get there without Tubi.

Exactly :)

So to be clear Masher, you removed the X Pipe in your final configuration? From what I have read in general applications it has little effect on sound, and removing it can limit performance.

From front to back: you have both sets of factory CATS, X-Pipe, 12" glass packs, stainless tubing straight to dual 3.5" tips (4 total) Also, what type of tips did you use? I have seen tips that have internal perforation in them like a mini glasspack.
My final set up.

Straight individual pipes from the two front CATS back with 2 12 inch paks about 1 foot behind the CATS. Removed X pipe. Removed back boxes. 3.5 inch tips from Anza.

I did not want each side to mix with the X pipe, I wanted to hear each side and not have the notes mix. ( just my preference, like my boat). I tried both ways and went with no X. The X pipe weighs close to 50 pounds. It is in my closet and so are the back boxes which are 30 or so pounds each and have to be very restrictive with that weight.
From what I have been told over the years and with this car, the lack of back pressure, theoretically you might lose a smidge of low end and now with the high flow set up, theoretically you would gain a smidge on the top end of the band. I cant tell any noticable differences.

I thought about going with square tips or something real different but chose the round. The double wall tips dont do nothing for sound unless you have a muffler.
My video camera allowance was used on my rear spoiler so I will work on getting a few clips soon.
 

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The only TUBI Masers I have heard have been on video so it is hard for me to judge any similarities/differences. I love mine now. Based on the ones I have heard online and listening to mine, they seem similar. The reason I tried all those combos today was to tone it down one or two notches and get a higher pitch.... This combo did just that. Maybe putting an empty X pipe would get you a more streamline, mixed note but I liked the sound of the individual pipes for sure.
I think mine is a small bit louder than a TUBI but the pitch seems the same to me.
 

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Sorry to hijack the thread, but Troesma wrote:

"BTW Bee, fancy looking at some circuitry (got it from Italy) to connect to the NIT to hook-on aftermarket DVD/NAV/etc using the OEM screen?"

So, is this for real? Has this been done? Any info would be greatly appreciated!

Art
 

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Discussion Starter #13
melton7a said:
Sorry to hijack the thread, but Troesma wrote:

"BTW Bee, fancy looking at some circuitry (got it from Italy) to connect to the NIT to hook-on aftermarket DVD/NAV/etc using the OEM screen?"

So, is this for real? Has this been done? Any info would be greatly appreciated!

Art
I know the I-Bus (CAN Bus) fairly well and actually designed the Sirius interface into my BMW so that artist/title was displayed on the MID and volume/channel was controlled by the steering wheel controls. My wife is now enjoying this integration while I listen to CRAP! So, yes I would be interested. If it's too expensive or hard to get, I'll build my own eventually. Need to find a bus connection and sniff the messages to find out where everything is.

So this isn't totally hijacked, thank you for some very interesting insight into the exhaust system. I'm now more confused than ever! I think Masher has it right. Do it until you're happy with it!
 

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BeeYouZeeZee said:
Thinking about getting my exhaust modded. Can't afford Tubi but the stock exhaust note is BORING. I'm NOT an exhaust guy so I'm asking for opinions from the experts.

Don't want straight pipes because they're just too loud for the car (IMHO). The question is.. has anyone removed the "Central Silencer" (the muffler in the center just beind the X-Pipe) but left the tail pipe boxes (resonators or mufflers?)? Do the tail pipe boxes lower the volume any? Change the note?
To answer the original question of removing the central "resonator" located in front of the "X" and leaving the rear boxes.....

1. YES, everyone who owns a Gran Sport in stock form is running this configuration. There is no center "resonator" in the stock setup. This is responsible for 90% of the sound difference between a 4200 coupe and gransport. Tubi is not doing a whole lot.

2. The "X" pipe weighs les than 2 lbs, it is only 10 inches of pipe. and YES, it is proven to not only INCREASE PERFORMANCE by expelling gasses faster, but also to influence the pitch of the exaust to be throatier. The "X" pipe is not related to the "resonator" except for the fact it is on the exhaust as well.

3. it seems the only way to get the high pitched whiney over-rev so many are looking for is to remove the rear set of cats.

Hope this helps,

Robb
 

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Discussion Starter #15
Robb373 said:
To answer the original question of removing the central "resonator" located in front of the "X" and leaving the rear boxes.....

1. YES, everyone who owns a Gran Sport in stock form is running this configuration. There is no center "resonator" in the stock setup. This is responsible for 90% of the sound difference between a 4200 coupe and gransport. Tubi is not doing a whole lot.

2. The "X" pipe weighs les than 2 lbs, it is only 10 inches of pipe. and YES, it is proven to not only INCREASE PERFORMANCE by expelling gasses faster, but also to influence the pitch of the exaust to be throatier. The "X" pipe is not related to the "resonator" except for the fact it is on the exhaust as well.

3. it seems the only way to get the high pitched whiney over-rev so many are looking for is to remove the rear set of cats.

Hope this helps,

Robb

Thanks Robb. The best I can tell, there is a set of pre-cats right off the exhaust manifolds and a set of cats directly behind them. Then straight pipes to the X-pipe, then what the Maserati shop manual refers to as the "central silencer" then straight pipes to the rear muffler boxes where the tips are connected. Am I right? Are the rear boxes mufflers, resonators or baffles?? Anyway, just removing the "central silencer" sounds like a good place to start.

Buzz
 

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Has anyone removed the second set of cats and tried to pass emissions, or had trouble with the check engine light?

So I'm thinking I will go with some 12 or 16" glass packs on Masher's recommendation, just need to decide on whether to keep the X Pipe or not. Does the Gran Sport have it?


Can MVP chime in on this thread and shed any light yet on what the setup he is planning to sell will look like??
 

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warning

cardiffGiant said:
Has anyone removed the second set of cats and tried to pass emissions, or had trouble with the check engine light?
I removed all cats including the precats. In their place I used Kreis-sieg's dummy cat, which is supposed to fool the computer and avoid a CEL. Well, it didn't quite work because sooner or later the malfunction light would come on.

Then I tried connecting "MIL Eliminators" to the O2 sensors, and the CEL problem only got worse. It's on all the time now. Supposedly the MIL eliminators work on de-catted Ferraris, but it didn't do the trick in my case.

So BEWARE removing the cats on your Maserati. (By the way, the pre-cats are part of the exhaust manifolds, to remove these you'd need new headers.)

There are still ways to pass emi$$ions with a CEL, but there's no need to go into that here.
 

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You'll need to fool your EGT as well because without cats the temperature will be off what's expected and throw a MIL or CEL as well.
 

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Discussion Starter #19
I think I have decided on a place to start based on Robb's excellent insight.

I'm going to leave the X-pipe (which I believe was carefully computer designed), remove the central muffler in the middle and leave the rear boxes in place. Per Robb, this is the stock GranSport setup.

I'm going to have the shop fabricate 2 pipes the diameter and length of the central muffler and have them "bolted-in" in place of the muffler. This way there's no welding and the central muffler can be put back in easily.

I believe the sound will be significantly more agressive (remains to be seen).

My baby's new and I have nightmares envisioning her getting cut up and welded on.
 

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Certainly have a shop do everything bolt-on. I had them do this when they removed the back boxes on mine. I've decided on a different final config:
X Pipe, no central resonator, two small straight through mufflers (probably glass packs), pipes back to the tips.

BeeYouZeeZee, I would be a little concerned about actually adding back pressure by removing the central resonator and then using standard mufflers like the stock back boxes. It seems the center resonator was designed specifically to imitate the end of the exhaust system, so anything beyond it (our stock back boxes) is transparent to backpressure of the complete system. By removing it, you may then be subject to the design of the back boxes (which are different than the GS ones I beleive.)

...Incorporating a resonator box into a system produces a layout along the lines seen in Fig. 9. With enough volume, the resonator box makes everything down stream appear invisible to the header's primary- and secondary-tuned lengths. With a flow capability of 2.2 cfm or more, the muffler appears virtually invisible from a flow standpoint. As a result, we have a muffled system that produces virtually the same power as an open exhaust."

This seems to make a lot of sense in our system, considering how quiet the stock system is, and how little extra power people are getting by completely opening it up with straight pipes.
 
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