I bought myself 4200 GT

[giorgio01]

How long on average it takes for the CEL to come up? I know Jasst said 250mls . I've done about 200mls so far but I've also isolated the battery in the meantime so I don't know if that resets everything and count starts again?

 

[philw696]

How long on average it takes for the CEL to come up? I know Jasst said 250mls . I've done about 200mls so far but I've also isolated the battery in the meantime so I don't know if that resets everything and count starts again?

Yes it does do that but the ecu's will still store codes.

 

[jasst]

It does vary somewhat, usually when it's cruising after having a good work out, has happened after 100 miles once, but does vary, always with some fault code ( can't remember what it is off hand) but something like p1028 or similar. Meaning the cats are cold, so I've wrapped the cat section in heat proof wrap, but hasn't made any difference.

 

[FIFTY]

Mine does it after about 6-8 hours of driving - always at a solid cruise on the motorway, error for cat efficiency (200 cell 5" diameter sports cats)

 

[giorgio01]

Mine does it after about 6-8 hours of driving - always at a solid cruise on the motorway, error for cat efficiency (200 cell 5" diameter sports cats)

Does it go in to limp mode?

 

[FIFTY]

Does it go in to limp mode?

No limp mode. Performance seems exactly the same.

I am thinking about changing my lambdas and thermocouple to new ones to see if that helps.

If it doesn't then I might have to bite the bullet and buy the Larini cat sections - however I have read reports of it still happening even with the Larinis but much less common

 

[giorgio01]

Update,
Looks like all is good (kind of) I mean as it should be. After few more miles the CEL light is on so I'm glad I haven't started on the center section ( x-pipe) as I have to incorporate a cat somewhere over there now.

 

[FIFTY]

Go for the largest diameter cat you can get hold of as the car needs it to breath... I managed to source 5" 200 cell cats to replace the tiny 100 cell ones I originally had welded in.

 

[hladun]

Everyone seems obsessed with changing the exhaust on these cars but I don't think you get anything in return. (well perhaps a thinner wallet and a lot of CEL's) OK, if you want to be a teenager and have a LOUD car I can see that. What limits the 4200 is the beautiful intake manifold. It has long inlet runners to get low end torque as befits a touring car. Ferrari kept the variable intake system for the 430 and the 4200 runs out of power because it can't breathe at higher rpm.

 

[FIFTY]

Everyone seems obsessed with changing the exhaust on these cars but I don't think you get anything in return. (well perhaps a thinner wallet and a lot of CEL's) OK, if you want to be a teenager and have a LOUD car I can see that.

Right...

 

[jasst]

Everyone seems obsessed with changing the exhaust on these cars but I don't think you get anything in return. (well perhaps a thinner wallet and a lot of CEL's) OK, if you want to be a teenager and have a LOUD car I can see that. What limits the 4200 is the beautiful intake manifold. It has long inlet runners to get low end torque as befits a touring car. Ferrari kept the variable intake system for the 430 and the 4200 runs out of power because it can't breathe at higher rpm.

One of the reasons for changing the 'cats' on these cars is because of the risk of the oem cats breaking up and being ingested and lunching the engine, quite well documented. Ask me how I know

 

[hladun]

One of the reasons for changing the 'cats' on these cars is because of the risk of the oem cats breaking up and being ingested and lunching the engine, quite well documented. Ask me how I know

So tell us...but make sure you tell us if you monkeyed with the engine/exhaust

 

[Zep]

I have to admit, in my personal view, an engine with 4 valve heads, variable camshaft timing, a specific output of nearly 100 bhp per litre, a red line of 7,500 rpm and peak power at 7000 rpm, isn’t especially optimised for torque.

There is some benefit to changing the cats, the breakup issues mentioned have happened to many cars, here and in the US and is unrelated, from what I can see, to exhaust modifications.

In any event, it’s up to people to make their own choices. Going on a thread about exhaust mods and saying there are pointless is a bit like walking into someone’s house and telling them you don’t like the wallpaper.

 

[hladun]

Zep,

A quick search on Google will give you info on manifold design. The Maserati manifold is designed to maximise torque...long, thin runners. Put another way, why do manufacturers make variable intake engines?

When I search on cat failures I find physical (road) damage or high cat temperatures due to modifications. I'd like to hear from someone who has had a cat failure in a stock 4200 engine without road damage to the cats. Just a question because I, and probably many others, have stock engines.

You're right I'm not a fan of exhaust mods, but readers of this forum would be well served to hear some facts.

 

[Zep]

Zep,

A quick search on Google will give you info on manifold design. The Maserati manifold is designed to maximise torque...long, thin runners. Put another way, why do manufacturers make variable intake engines?

When I search on cat failures I find physical (road) damage or high cat temperatures due to modifications. I'd like to hear from someone who has had a cat failure in a stock 4200 engine without road damage to the cats. Just a question because I, and probably many others, have stock engines.

You're right I'm not a fan of exhaust mods, but readers of this forum would be well served to hear some facts.

Yes, the inlet runner are long and thin, looking at the set up on a F136 in, say, a 458 Scuderia, they are not much shorter, given that the pulse tuning length is from a change in crosssectional area. They do feature a crossover with a valve. My point wasn’t that they aren’t long(ish) and thin, but more that it can’t be looked at in isolation given the output from the engine and the other features aimed at increasing top end power. We are not talking about a lazy pushrod V8 here.

I’m not going to spend the time finding examples for you because you have already made up your mind. However I know of one unmodified car personally with a failure and a google search turns up a fair number of examples in standard cars. This is also an issue that has impacted Ferraris.

People on this forum know that the majority of posts are opinion and personal experience rather than outright fact, yours and mine included.

 

[hladun]

I don't disagree that this topic is full of opinion and legend, but here's a recent example of an "ate the cats" post on the other Maserati forum:

New engine

www.maseratilife.com

Sounds pretty bad and yet another Maserati cat failure, but if you search on the OP's name here's an earlier post:

Cat rattle

www.maseratilife.com

I admire the OP because he's honest and the thread starts with "So after modifying the exhaust my cats broke up and are now rattling,..."
I'm just saying be careful what you do and I feel for the OP who has now wrecked his engine. So if you're thinking about modifying your exhaust then think twice and remember the aftermarket guys are trying to sell you something.

 

[FIFTY]

@hladun I suggest not derailing the OPs project thread, please(?)

My opinion is based on a different experience than what you state. Maybe you can start your own topic call it something like "the hating on monkeyed exhausts thread" and we can take it up there.

 

[giorgio01]

My car didn't have any cats whatsoever but standard exhaust otherwise. In my case I have to ad the cat and modify the rest at the same time.

 

[hladun]

My car didn't have any cats whatsoever but standard exhaust otherwise. In my case I have to ad the cat and modify the rest at the same time.

Yes, I understand. The information I was looking for is how much latitude does one have or are you best served by staying with the OEM exhaust. It's something you'll have to deal with.

 

[giorgio01]

Yes, I understand. The information I was looking for is how much latitude does one have or are you best served by staying with the OEM exhaust. It's something you'll have to deal with.

Since I'll have to fit one anyway I'll fit aftermarket euro 3/4 cat. I don't have/want to leave the exhaust OEM. I like what you call asbo and now you can barely hear it which is not good for a sport car in my opinion obviously.