SportsMaserati Exhaust Modification Guilde

conaero

Forum Owner
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34,593
Some of you may have noticed I have not been around much the past few days. I have been up with BennyD playing with exhausts and here is our findings:

Well guys, that was an interesting morning. I went to stay with that righteous pillar of our community and all round good guy BennyD last night and this morning we took my GS to his mate John, who had a spare ramp, and we fitted a new unsilenced X-pipe and modified GS rear boxes. The whole thing came apart pretty easily, although it was a bit of a faff getting the rear wheel arch liners out. Then we did a bit of messing about fitting, and videoing, various combinations of parts so that we have a video record of what does what with what. Here is a sequence of videos that is best listened to with earphones.

Firstly, this is what a GS sounds like as standard with the valves closed:



Standard GS with valves open:



I think you'll agree it leaves a lot to be desired! To try and improve matters we then fitted an unsilenced X-pipe, leaving on the standard GS rear boxes, and tried it first with the valves closed and then open:



Better! There is a bit more bass and volume and there is the first sign of the pops and crackles. But, whilst better, it's still not great. I suppose it would suit those who want a bit more, but not too much. We then fitted the heavily modified rear GS boxes and refitted the standard centre box/resonator. We thought this would make a noticable difference as they are virtually straight through:



We were wrong! It sounds a lot like standard and I guess it shows how much the standard cats and resonator kill the sound before the back end. Then we removed the standard centre box and replaced it with the unsilenced X-pipe leaving the modified rears on. First, valves closed and then open:



Success! With the valves closed it sounds a bit fruitier than the standard sport (valves open) mode but is still pretty quiet. With the valves open it sounds much better; very sporty, a lot louder and it now has a nice line in pops and crackles. Benny said it sounded fantastic when I went past him on the motorway. On the road in sport, the sound has now got a lot harder edge to it than standard and much more volume. However, and this is the good bit, there is no resonance in the cabin and very little increase in interior volume either, until you open the windows! I guess it proves what we have been saying all along; you need to change two of the three parts to make a worthwhile increase in sound volume and quality. (The three parts being; front pipes and cats, the centre box and rear boxes).

All in all, a very successful and relatively cheap mod which transforms the car into what it should have been from the factory. Thanks to John at GT Cars (Warrington) for the use of his ramp, technical input and coffee!
 
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conaero

Forum Owner
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34,593
I am now living with the new exhaust for the next few day and will be taking the car to Llandow now, so will report back with an update, but results so far are encouraging and by no means droney or invasive and motorway cruising, there is no noticeable audible difference over standard.
 

Maser Sod

Member
Messages
1,962
Cool stuff, Matt.

It's good fun getting a Maser to sound how you want. Getting new exhaust systems put into my GTV V6 and my GranSport was some of the best money I've spent, in terms of smiles generated.
 

SimonCC

New Member
Messages
690
Excellent Matt and Benny! Really good to hear the subtle changes in sound and volume.

Effectively I have ended up with the same mod as you in that I have removed the secondary cats and added Larini rears. Makes all the difference.

Brilliant work chaps! :thumb1:

What have you done to the GS back boxes? I know you've removed some of the innards. But what else have you done to create your modified rear boxes?
 

BennyD

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Thanks for your positive comments guys, it's nice to hear you appreciate our efforts to help with the age old exhaust conundrum! We completely changed the pipe work and replaced a lot of the standard perforated piping with solid walled pipe. This makes the 'loud' side virtually straight through.
 

SimonCC

New Member
Messages
690
Did you only replace the 'loud' (valved) side pipe work inside the box Benny and leave the unvalved side as standard?

Must have been fun doing this! How long did you take trying the different set ups?

Appreciate a lot of prep has gone into this before you even got to work in the garage. Good work!

Also, how does Matt's car now sound in relation to yours? And what set up do you have (if it's different to Matt's)?

Sorry for Question Time, but interesting subject! Cheers... :approve:
 

CliveP1

Junior Member
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578
nice one lads, it certain answers some questions over the age old one what to do with exhausts.
 

BennyD

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14,994
Did you only replace the 'loud' (valved) side pipe work inside the box Benny and leave the unvalved side as standard?

Must have been fun doing this! How long did you take trying the different set ups?

Appreciate a lot of prep has gone into this before you even got to work in the garage. Good work!

Also, how does Matt's car now sound in relation to yours? And what set up do you have (if it's different to Matt's)?

Sorry for Question Time, but interesting subject! Cheers... :approve:

The 'quiet' side is technically the same as standard in as much as it supplied through perforated pipe which allows the gases to expand through it and into the acoustic packing thereby quietening it down.

This is the second version. Version 1 is on Conaeros 'old' spyder (now owned by Zagato).

Mine is quite a bit louder than Matts system. They are identical from the cats back but I have Larini sports cats on mine whereas Matts are still standard. Last year at Le Mans I ran straight through rears instead of the valved boxes and it was quite a bit louder still. It roared and snarled on acceleration and the pops and bangs on the overrun were like artillery fire! Great fun on an event like that but it was a bit wearing for every day use, hence the push to develop something that was loud but could be calmed down by shutting the valves. Personally, I don't really care what it sounds like with the valves shut, be it a kazoo or anything else similar, as long as it sounds good when 'going for it' and it does.
 

BennyD

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14,994
If you want one, let me know and I can organise it. However, all this experimenting is applicable to the 4200/ GS not the 3200 which I see in your avatar. The exhaust mechanics and dynamics are completely different between the two and the turbos on the 3200 quieten the exhaust sound down so what works for the 4200/GS won't necessarily work on the 3200.
 

MAF260

Member
Messages
7,662
Option 3 is by far the best sound and is really what I would have expected from the standard car! I'm surprised how quiet the modified boxes are with the standard, silenced x-pipe. The combination of x-pipe and rear box mods makes a huge difference.
I'm glad I'm having a sports silencer fitted when I change my manifolds and fit sports cats. With the Larini rear boxes I reckon it would be too much!
**Now waiting for general abuse from Benny regarding the last sentence!
 

BennyD

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14,994
Option 3 is by far the best sound and is really what I would have expected from the standard car! I'm surprised how quiet the modified boxes are with the standard, silenced x-pipe. The combination of x-pipe and rear box mods makes a huge difference.
I'm glad I'm having a sports silencer fitted when I change my manifolds and fit sports cats. With the Larini rear boxes I reckon it would be too much!
**Now waiting for general abuse from Benny regarding the last sentence!

No mate, no need! As Matt said in the blurb, option 3 is good way to go for those wanting a fairly subtle increase but Matt was after something a bit more Gutsy. Also, the sounds recorded when revving whilst stationary are completely different to when accelerating under load. IMO, Matts sounds fantastic under load as those going to Llandow will appreciate. TBTW, to those who are going to Llandow, please post up your impressions and let us know if we are on the right track. Thanks.
 

Contigo

Sponsor
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18,376
If you want one, let me know and I can organise it. However, all this experimenting is applicable to the 4200/ GS not the 3200 which I see in your avatar. The exhaust mechanics and dynamics are completely different between the two and the turbos on the 3200 quieten the exhaust sound down so what works for the 4200/GS won't necessarily work on the 3200.

Yep I realise that I can't fit it to mine but was just stating which one I liked the sound of. I am going down the Larini race pipes route....
 

dunnah01

Member
Messages
648
Great work gents - you must have spent a fair bit of time and effort swapping parts over so credit to you.

If I could get my 3200 to sound like any of the setups I'd be a happy bunny - unfortunately removing the turbos and adding a litre to the engine isn't that practical (and buying a GS isn't an option :0036:).
 

MAF260

Member
Messages
7,662
No mate, no need! As Matt said in the blurb, option 3 is good way to go for those wanting a fairly subtle increase but Matt was after something a bit more Gutsy. Also, the sounds recorded when revving whilst stationary are completely different to when accelerating under load. IMO, Matts sounds fantastic under load as those going to Llandow will appreciate. TBTW, to those who are going to Llandow, please post up your impressions and let us know if we are on the right track. Thanks.
By option 3 I meant the combo of unsilenced x-pipe plus the modified boxes. The best sound of the combos you show by far.
Mine already sounds quite beefy with just the valved Larini rear boxes. With the changed manifolds and sports cats I reckon mine would be too loud for 'every day' use if I had an unsilenced x-pipe as well. I'm going to bin the standard (very heavy) x-pipe and resonator and replace it with a sports silenced (i.e. straight through) pipe. I'm removing 2 600 cell cats and 2 400 cell cats, the standard x-pipe resonator and fitting 2 200 cell sports cats and a sports x-pipe. I'm very excited/nervous about the outcome!!
 

Neilf1965

Junior Member
Messages
126
A pair of straight through rears from Marios has given mine a nice sound at idle and whilst under load.
Neil.