Yet Another Exhaust Thread!

mchristyuk

mchristyuk

Junior Member
Messages
668
Ok 4200/Gransport owners..

My 3200 had a decat and Tubi rear exhausts and sounded great. However it was a bit too loud for my 8 month old daughter to travel any great distance in. So I want to upgrade the exhaust on my 4200 but without it being deafening when cruising.. loud with the pedal down, but sensible (ish) when just poodling along.

So for the moment I've decided that I should go for some kind of X or H pipe, delete the resonator box but keep the stock back boxes. All well and good.

My dilemma is what to do about the CAT setup whilst we're under there as it currently runs the US style headers with the CATS built in and I want to minimise my risk of engine damage without going to the £££ of Larini's. As far as I can see I have two options...

1) Gut the primary cats and move the Lambda sensor to after the second set of cats.
2) Remove the secondary cat and hope that any break up of the primary cat comes out through the vacant space left by the secondary cat.

Now, option 2 is the easiest but then what do I do when the primaries finally do give up the ghost? New headers? Open them up and weld in after market cats?

Option 1 removes the worry of the primary cats ever trying to kill my engine, but is there enough cable to actually move the sensor to after the second set of cats?

Over to you boffins...

Mark
 
Contigo

Contigo

Sponsor
Messages
18,376
John can answer your question about length of cable to run after the secondaries. I am still amazed at how shite the design of the 4200 exhaust system is.
 
maverick

maverick

Member
Messages
1,982
mchristyuk said:
Ok 4200/Gransport owners..

My 3200 had a decat and Tubi rear exhausts and sounded great. However it was a bit too loud for my 8 month old daughter to travel any great distance in. So I want to upgrade the exhaust on my 4200 but without it being deafening when cruising.. loud with the pedal down, but sensible (ish) when just poodling along.

So for the moment I've decided that I should go for some kind of X or H pipe, delete the resonator box but keep the stock back boxes. All well and good.

My dilemma is what to do about the CAT setup whilst we're under there as it currently runs the US style headers with the CATS built in and I want to minimise my risk of engine damage without going to the £££ of Larini's. As far as I can see I have two options...

1) Gut the primary cats and move the Lambda sensor to after the second set of cats.
2) Remove the secondary cat and hope that any break up of the primary cat comes out through the vacant space left by the secondary cat.

Now, option 2 is the easiest but then what do I do when the primaries finally do give up the ghost? New headers? Open them up and weld in after market cats?

Option 1 removes the worry of the primary cats ever trying to kill my engine, but is there enough cable to actually move the sensor to after the second set of cats?

Over to you boffins...

Mark
Click to expand...

Yes the cable is long anough as it runs towards the front then towards the back again , all you need to do is reverse the clip / bracket which holds the cable connector by 180* than you will find the cable will easily reach the rear of the seconds . See pic
image.jpg
image.jpg
 
Contigo

Contigo

Sponsor
Messages
18,376
Then you will need need a centre pipe and some Larini rears. That's what John's is missing now a set of valved Larini's.
 
Panicracing

Panicracing

Junior Member
Messages
376
On my GS I also have U.S. style headers. Secondary cats and centre box gone. Replaced with Larini straight thru front sections and x pipe. I also have 2 year old and no issues with noise or resination but never push to hard when she's in the car. This was done about 2 years ago and had no issues. I ordered valves Larini rear boxes about 3 weeks ago and due anytime now.

Sent from my LG-D855 using Tapatalk
 
Panicracing

Panicracing

Junior Member
Messages
376
06454a1385d82b920162bee256aa1aae.jpg


Sent from my LG-D855 using Tapatalk
 
B

BenjaminBraddock

New Member
Messages
70
mchristyuk said:
Ok 4200/Gransport owners..


So for the moment I've decided that I should go for some kind of X or H pipe, delete the resonator box but keep the stock back boxes. All well and good.

My dilemma is what to do about the CAT setup whilst we're under there as it currently runs the US style headers with the CATS built in and I want to minimise my risk of engine damage without going to the £££ of Larini's. As far as I can see I have two options...

1) Gut the primary cats and move the Lambda sensor to after the second set of cats.
2) Remove the secondary cat and hope that any break up of the primary cat comes out through the vacant space left by the secondary cat.

Now, option 2 is the easiest but then what do I do when the primaries finally do give up the ghost? New headers? Open them up and weld in after market cats?

Mark
Click to expand...

Hi Mark

Option-1 sound like an excellent mod.

My exhaust is fairly close to Option-2 in that I had the secondary cats removed, have an H-pipe and am back to factory rears.

When we catch up you'll be surprised at how much quieter it is now without the Larini rears on, but it still sounds purposeful and have to say now I'm used to it I don't miss the Larinis as much as I did at first. I think it may work well for you.

Simon
 
mchristyuk

mchristyuk

Junior Member
Messages
668
Simon/Panic,

Certainly getting rid of the secondary cats is the easiest option.. it's just in the back of my mind at some point the primary cats will break up and need fixing. Which will be easier, welding in new cat material to the primaries or just replacing the secondaries as and when?.. I think Option 1 may be initially more work but will be more "future proofed"...

Cheers

Mark
 
Caldy999

Caldy999

Junior Member
Messages
445
Collected mine today - primary cat delete, replaced secondary cats with sports cats, central kidney silencer/x-pipe replaced with straight through x-pipe, standard rears. Only crawled home through traffic but on odd occasions managed to rev it out. It's surprisingly quietish but with a nice warble and the good news is that I do seem to have the throttle blip!

Decat 2.jpg

Decat 1.jpg

I'll try to get a sound video asap.
 
Caldy999

Caldy999

Junior Member
Messages
445
http://www.theexhaustdoctor.com/

I bought the flanges from a forum member, Maverick kindly made me the temperature probe bosses and I bought a used Larini centre x-pipe from a forum member but it appeared to be an incorrect part so a new one was fabricated.
Took a little longer than expected owing to snapped studs etc but a quality job.
 
safrane

safrane

Member
Messages
16,852
FYI there is a member on the maserati club uk site who is asking for some replacement factory cats if you want to move them on.
 
Caldy999

Caldy999

Junior Member
Messages
445
safrane said:
FYI there is a member on the maserati club uk site who is asking for some replacement factory cats if you want to move them on.
Click to expand...

Hmm thanks for the tip but I'm not sure - I think mine may be a keeper in which case it wouldn't matter but if I were ever to sell.....
 
FIFTY

FIFTY

Member
Messages
3,100
They look great Caldy. Let us know what you think of the throttle response when you get to drive her properly.
 
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