[themast]

Hello all,

if you have followed some of my recent posts you know that I had been investigating changing the mufflers on my 2004 Coupe CC.

Previous owner had setup the car with a Larini X-Pipe and Tubi Style mufflers. While the car sounded glorious and it was extremely engaging to drive it was a bit too loud for my tastes and how I am using the car (dinner out with wife, running occasional errands etc.).

The Tubi sound however was intoxicating and addicting and I wanted to find a way to retain some of the Tubi character while toning down the overall volume. With various feedbacks from this forums and some additional research and thinking I concluded that installing a pair of Gransport stock mufflers would help me achieve a good balance in terms of sound and volume.

Member Lambertius was extremely kind to sell me a pair of GS mufflers at a great price and that put the "project" machine in motion.

I made some before and after videos and I am debating whether to post them or not because it is very difficult to properly capture exhaust note with an amateur camera setup.

So let me provide my impressions first. The X-Pipe with Tubi Mufflers had a sublime sound above 3500 rpm, high pitched but sophisticated and screamed all the way up to the rev limiter. However, at low RPM was particularly "open" and loud, and between 2,000 and 3,000 RPM introduced a noticeable droning in the cabin.

The X-Pipe with GS exhausts (which I understand was the standard setup for US GS cars) is quieter than the Tubi at all RPM and stays always throatier while the Tubi was more open and Ferrari-like if you wish. With the valves closed, the droning between 2,000 and 3,000 RPM is completely gone.
However, what it is interesting, is that with valves open, the volume does not go up but it gets deeper and "boomier". At high RPM during acceleration the sound is actually very similar between valves closed and open and it sounds actually almost better with valves closed because of the higher pitch.
The open valves make a more noticeable difference at idle and on tip-out where thelet the exhaust sound gloomier, and they allow a bit more crackles (albeit at a much reduced volume compared to the Tubi, which sometimes almost sounded like a backfire, it was beautiful!).

So overall I am very happy with the result because the car becomes more usable for me. However, I wished that with valves open I retained a bit of the high pitch Tubi tone while it is actually the opposite!

Ok, so now to the install... but first I wanted to show off the switch! I had Billet Automotive make me a custom switch with a clef for the exhaust. I think it looks very nice in the cabin.

The mufflers removal is a bit tedious but quite straight forward.

First remove wheels and wheel arch linings (there is a screw and a bunch of hex bolts, quite straight forward)

Mufflers are held in place with 2 nuts on the outside, a nut at the flange connecting to the pipes going under the car, and 2 nuts at the back.

Remember to place towels around the exhaust tips before staring to wiggle the exhaust out to avoid scratches on the bumper paint. Also, when you re-install the mufflers place some spacers around the tips to help leveling them before you tighten the bolts.

The Tubi and the Gransport mufflers have a very similar outside construction, in fact they were both manufactured by Tubi. The Tubi are nicely polished and a bit lighter (I did not weigh them) since they have less material inside and no valves.

For the control system, I bought a vacuum solenoid off Ebay from a Maserati Levante. It could be really any vacuum solenoid I think but this one came with a connector and I liked that it was off another Maserati.
I attached the solenoid behind the cabin tub, using a bolt that was used to hold another wire (had to make a little bracket to properly hold it in place, I will eventually add a plastic cover too).

I wrapped the wiring into 1/4 split tubing and brought it to the back of the car (more on that later). For the vacuum hoses I used 4mm, however I think 3mm works as well, in fact at the vacuum tank vacuum hoses are 3mm internal diameter.

Vacuum hose goes to the front following fuel and brake lines on the left of the car and to the back above the F1 transmission hoses. There it splits to reach the two mufflers' valves.

The vacuum tank is behind the left front wheel. After removing the wheel and the lining, the tank will be right there.

I placed the check valve here at the vacuum tank.

For the vacuum solenoid electrical wires, I followed a line in the wheel arch and found a grommet that took me into the trunk.

Continues in next post.

 

[themast]

And this is the wire in the trunk.

I did not take a picture of it but I placed a relay next to the CD charger.

For power, I originally wanted to use one of the fuses in the trunk but I discovered that they are all always live (at least the low-amp ones for accessories). So I had to find a different source for power.

My car was previously modified so that the turn-on wire for the amplifier was hard wired to a 12V switched source under the arm rest. I believe that in vehicles with the original NIT, the amplifier turn-on wire will be controlled by the NIT, so the wire highlighted below won't work for this application. If you have removed your NIT and want to follow a similar approach I can dig up some photos of the connection under the armrest to make this work.

The harness pictured below is behind the battery and even if my car originally had the ASK amplifier (that I removed) it is probably similar in every car.

For the wiring itself, I wanted the valves to be closed at startup. To achieve that, the solenoid had to open when engine was running so that vacuum could pull the valves shut (valves are normally-open open on these mufflers). Moreover, I wanted the control switch to illuminate when it is depressed (valves open) and to illuminate (dimmed) when headlights are on. So this is how the wiring looks like (I forgot include the fuse to the 12V battery in the diagram)

The way it is wired, the solenoid gets 12V when the car is started and then the relay cuts off the solenoid when the exhaust switch is depressed (hence opening the valves) and sends 12V to the switch so that this illuminates.

More details on how to route wires from the trunk to the center console can be found here.

Coupe/Spyder/4200 Aftermarket Radio, Backup Rear Camera...

Hello all, I wanted to share my experience with installing an aftermarket radio in my new-to-me 2004 Coupe equipped with the optional auditorium system. My situation was a bit unique as the previous owner had already removed the NIT and installed a tablet in-lieu of the head unit. Also, he had...

www.maseratilife.com

That's all folks!

 

[Catmanv2]

Love the switch

Does your amplifier control line stay high when the NIT is turned off, though?

C

 

[Ramp]

Very nice write up.

 

[themast]

Love the switch

Does your amplifier control line stay high when the NIT is turned off, though?

C

Now that I think about it, you are (almost ) absolutely right.

The NIT was previously removed from my car and the amp turn-on wire was hardwired to a 12V switched source under the center armrest to bypass the NIT switching function. I forgot about it when I installed "my" muffler control system on the car, I will edit the writeup to clarify this point.

Also, perhaps my amplifier failed because with this modification it was always ON when ignition was on. I did not think about this aspect.

 

[.6845]

This is magnificent…..I wish I had your skills.

Kindly,
Stephen

 

[themast]

I have been on the fence regarding publishing these because I think audio clips introduce a lot of uncontrolled variables. However, I tried to record the before and after as closely as I could. Therefore, this should an idea of the differences, at least directionally.

Few of remarks:

• The videos don't really capture how much louder are the Tubi mufflers. Don't get me wrong, they are not extreme but the videos don't fully capture the difference in my opinion.
• I think the last bit of the driving comparisons with the low rpm in the tunnel highlights that difference well, and quite frankly that is the reason why I wanted to replace the Tubi. Flat out they are glorious but I wished they were quieter at low RPM.
• Yes, it may sound counter-intuitive but under hard acceleration the GS mufflers may sound louder with the valve closed. I think that is because with the valve open the sound gets deeper, with more pronounced bass tones. In real life, at idle and at tip off, they actually feel louder with the valve open because they are "boomier" but under hard acceleration they feel very similar. While driving, with valve open there is not a huge difference but the "boomier" sound makes the driving experience sportier.

Tubi Mufflers Revving

GS Mufflers Revving

Driving Comparisons (recorded with driver's window down)

 

[campipilot]

Maserati Gransport, Larini exhaust

'05 Maserati Gransport, full Larini exhaust. The car has most Formula Dynamics mods.

youtube.com

ok this is full larini exhaust…mufflers, x pipe/H pipe, decats……I think it sounds amazing. BUT I will say I do wish it weren’t quite as loud. If I drive it real mellow it is fairly quiet and deep and throaty. Jeff at FD did it to my car. My car has almost everything FD offers.
that reminds me. Jeff still has all my old pipes, cats and mufflers I need to get from him!

 

[themast]

Maserati Gransport, Larini exhaust

'05 Maserati Gransport, full Larini exhaust. The car has most Formula Dynamics mods.

youtube.com

ok this is full larini exhaust…mufflers, x pipe/H pipe, decats……I think it sounds amazing. BUT I will say I do wish it weren’t quite as loud. If I drive it real mellow it is fairly quiet and deep and throaty. Jeff at FD did it to my car. My car has almost everything FD offers.
that reminds me. Jeff still has all my old pipes, cats and mufflers I need to get from him!

That sounds great. At the end it boils down to personal taste and circumstances. I live in a densely populated (sub)urban area and use my car a lot for family errands and outings. Under those circumstances I always felt that the car was unnecessarily loud. However, if I lived in a more secluded area and used the car mostly for driving events, spirited driving, etc. it would have been a different story.

 

[themast]

Update.

When I originally did this job I wanted to replicate as much as possible the GranSport setup. While I don't think this is necessary, since it was not too expensive I ordered the rigid vacuum line for the GranSport but it took a long time to arrive, so I temporarily installed a rubber hose under the rocker as an interim solution.

This week end I tackled the install and while not complicated it was obviously a little project. While I was there, I also installed a little box to protect the solenoid. I don't drive much in the rain, but I think the GS has a small cover (which I could not find as a spare part) and again I wanted to replicate the setup.

This is from the back, looking toward the front. I found a box that fitted perfectly in that recess.

The rigid line was a perfect fit. I added some ziptie holders to secure it to the undercarriage in areas where no other hooking points were available.

The rigid line comes in and then back out. I was a bit confused at first as mine was a bit bent and it looked like it wanted to follow the other lines.

And then it bends up in between the frame and the wheel arch lining.

Totally unnecessary but I am happy with the end product!

 

[lambertius]

Really impressed with the job you did, and glad my mufflers went to a good home!

 

[themast]

Really impressed with the job you did, and glad my mufflers went to a good home!

Thanks again for the great deal on the mufflers!

The only issue is that I am missing a bit the Tubi. Once you hear the V8 in all its glory it is difficult not to miss it. I have other things to address now but later on I want to see if I can modify the mufflers to have a bigger delta between valve closed and valve open. Valve closed are perfect for me but I would like a bit more volume with valve open! I am not sure whether that is achievable with this design with the valves on the tips but I will look into it at some point.

 

[lambertius]

That's exactly the issue I was having. The Larini's are on point when open, but too loud when closed. The GS mufflers are by far the most polite street option while adding some spice.

Ultimately I think it is easier to modify the Larini Mufflers than the GS which is why I kept them.

If you want to modify them, you want to cut the top of the muffler off, pull out the packing and run a solid pipe instead of perforated pipe, then you'll get what you want.

 

[themast]

That's exactly the issue I was having. The Larini's are on point when open, but too loud when closed. The GS mufflers are by far the most polite street option while adding some spice.

Ultimately I think it is easier to modify the Larini Mufflers than the GS which is why I kept them.

If you want to modify them, you want to cut the top of the muffler off, pull out the packing and run a solid pipe instead of perforated pipe, then you'll get what you want.

Well, the issue though is that if I do that, then with valve closed the gasses don't have anyway to go.

This is why I think on the Granturismo they put the valve before the muffler so that when closed, the gas are forced to the muffled side. When open, the gas can escape through the "straight" side. Not my photo and these are modified anyway but I think that on these cars they put the valve where the red lines are. That way, when the valve is closed, gasses will follow the other path and expand in the muffler. When the valve is open, gasses will have a path of least resistance in the straight pipe section.

With a valve at the tip I am not sure how to achieve this, if possible at all.

 

[lambertius]

Not sure if I sent this to you, but I stick a boroscope inside the GS mufflers.

The GS mufflers have a restriction and baffle on the default side, they will still muffle if you pull the packing out and replace the inner pipe with a solid pipe. When the flaps are open the mufflers are a straight pipe.

 

[themast]

Not sure if I sent this to you, but I stick a boroscope inside the GS mufflers.

The GS mufflers have a restriction and baffle on the default side, they will still muffle if you pull the packing out and replace the inner pipe with a solid pipe. When the flaps are open the mufflers are a straight pipe.

This is where I am confused. Yes I saw the video and I have a general understanding on how the internals are laid out. The problem that I have is that if you put a solid pipe on the valved section, when you close the valve, the gasses won't have anywhere to go. See below

To make it work I have to find a way to use the valve at the tip to force the gasses either through a straight pipe or through a baffled section. What I have in mind, conceptually, looks like the sketch below. With valve CLOSED, the gases will flow more easily to chamber 2 and out (this would be the loud side).
With valve OPEN, some of the gasses will be able to flow out of the tip with the valve and expand into chamber 1, that will have some perforations and sound dampening materials inside (this would be the quiet side).
This is still a rough concept, and unfortunately I have not been able to find an image of an actual GS muffler cutout to better understand what to expect internally.

Just for reference, this is supposedly how a Tubi looks like inside

And this is how a stock 4200 muffler looks like

 

[themast]

I need to achieve this, but with the valve at the tip. I am not sure if it is possible.

 

[lambertius]

I think you're close to understanding what is happening inside but not quite there. I've put my MS paint skills to work here.

The tubi muffler and the GS muffler are exactly the same internal layout, so I've drawn over both of them to try and help you visualise what is happening.

On the GS image, the black pipe is a perforated tube. The rest of the muffler is packed with fibreglass.

The red line is the default gas pathway, which passes through a restriction (a perforated baffle in yellow) which I've circled in the screen shot from the boroscope. The arrow is the path to the valve, which is closed by default (the blue line on the GS muffler). This means that when the valve is closed, the factory muffler is a single-chamber baffled muffler. The 4200 muffler is a three chamber baffled muffler.

In the screenshot you can see all the perforations in what would be the black tube on the GS muffler. This is what is wiping out most of the extra noise, even though when the valve is open the car is technically straight piped.

What I'm suggesting you do, is that you open the GS muffler, and replace the black pipe with the same solid pipe as the tubi muffler, but retain the restriction to the default tip.

 

[themast]

I think you're close to understanding what is happening inside but not quite there. I've put my MS paint skills to work here.

The tubi muffler and the GS muffler are exactly the same internal layout, so I've drawn over both of them to try and help you visualise what is happening.

On the GS image, the black pipe is a perforated tube. The rest of the muffler is packed with fibreglass.

The red line is the default gas pathway, which passes through a restriction (a perforated baffle in yellow) which I've circled in the screen shot from the boroscope. The arrow is the path to the valve, which is closed by default (the blue line on the GS muffler). This means that when the valve is closed, the factory muffler is a single-chamber baffled muffler. The 4200 muffler is a three chamber baffled muffler.

In the screenshot you can see all the perforations in what would be the black tube on the GS muffler. This is what is wiping out most of the extra noise, even though when the valve is open the car is technically straight piped.

What I'm suggesting you do, is that you open the GS muffler, and replace the black pipe with the same solid pipe as the tubi muffler, but retain the restriction to the default tip.


View attachment 148511



View attachment 148509

View attachment 148510

Ah, now I understand your boroscope videos. I did not understand that first part was taken from the "engine" side and second part from the valved tip. Also, I did not appreciate that the GS and the Tubi also had the same internal general design.

However, if I got that right, the valved side is also perforated and the yellow baffle is actually inside the "main" conduit. So I think my final design would have to look like the sketch below.

The path to the valved tip has to be substituted with a solid pipe. The rest left unaltered (TBD whether to leave the sound dampening cloth inside).

Makes sense?

 

[lambertius]

You're getting close, but if you just grab a bright light and look inside the default tip, you should be able to see how it is assembled!

Honestly, if you just cut it open you'll see what you need to do pretty quickly!