[clivemajor]

Hi

I have a Brera 3.2 S and unsure what to do or rather what is best to do regards the secondary Cats. After reading some posts on AO and other site have a few questions:

1. MOT wise does there have to be a physical Cat/s if the car is meant to have them
2. Will the ECU/computer go crazy if decat. If so hows best to deal with this
3. Is there much difference performance wise between decat and sports cats
4. I notice some custom sports cat/exhaust use one secondary cat replacement and other two. What are the benefits of both

Think that's most of my questions

Any advice is much appreciated

 

[lizard]

The most restrictive ones are those in the exhaust manifolds. If you already fitted catless exhaust manifolds, I wouldn't bother much with secondary cats, as gains aren't that high probably.

Autodelta have those in shop, but they do come at a price: Autodelta Shop

They also have sport secondary cat, what you probably already know.

 

[clivemajor]

The most restrictive ones are those in the exhaust manifolds. If you already fitted catless exhaust manifolds, I wouldn't bother much with secondary cats, as gains aren't that high probably.

Autodelta have those in shop, but they do come at a price: Autodelta Shop

They also have sport secondary cat, what you probably already know.

Thanks for the reply Lizard

I've still got standard manifolds, mainly due to cost as the engine needs dropping to fit the manifold.

So is there little point in replacing the secondary cats or decating ?


Thanks

 

[Pud237]

Little point doing anything with the secondary cats if you still have those awful manifold-cats fitted.

 

[clivemajor]

Little point doing anything with the secondary cats if you still have those awful manifold-cats fitted.

Thanks Pud

Does any one know the performance increase when removing the pre-cats? as it's over 2K including fitting

Thanks

 

[dc]

I wish somebody offered an after market exhaust manifold for the 2.2, they don't seem to be made anywhere..

 

[lizard]

Thanks Pud

Does any one know the performance increase when removing the pre-cats? as it's over 2K including fitting

Thanks

I would speculate - somewhere around 15 bhp. Not worth it in my opinion, but you do get more responsive engine as well :biglaugh: Usually mods on non-turbo engines don't make sense as gains are minor and costs are high. For faster throttle response you can also get a remap how throttle pedal responds.

This mod is much cheaper on older V6 where you just get secon-hand exhaust manifolds from older versions which were catless. I payed 50€ per exhaust manifold. A bargain really.

 

[clivemajor]

I would speculate - somewhere around 15 bhp. Not worth it in my opinion, but you do get more responsive engine as well :biglaugh: Usually mods on non-turbo engines don't make sense as gains are minor and costs are high. For faster throttle response you can also get a remap how throttle pedal responds.

This mod is much cheaper on older V6 where you just get secon-hand exhaust manifolds from older versions which were catless. I payed 50€ per exhaust manifold. A bargain really.

Thanks Lizard

Yes same here to much cost for the gain.

May be selling soon, for a 370z. love the Brera but for the running cost it's not that quick. I know it's not all about speed, hence test driving the 370z to see if it feels the same to drive

Cheers

 

[Aeroresh]

Ive got full decat on mine (manifolds and secondaries)

Im thinking of putting the secondaries back in though as the system seems to be lacking back pressure so struggles a bit under 2000rpm and even remapping hasnt helped in this respect.

It does fly at the top end though and the rasp that comes out of the pipes is something to behold. Anyone who says these GM motors cant sound as good as a Busso havent heard mine!

 

[clivemajor]

Test drove a 370z today and I was pleasantly disappointed :biglaugh:

1. Was it faster than my Brera - Yes but not pin you in seat as I was expectling
2. Was it much faster - No
3. Did it feel as nice to drive - Absolutly NOT
4. Was the general quality better - Absolutly NOT
5. Will I be buying one - I think you can guess this one!

Below are just my personal opinions, and not a dig at 370z!

Initially the interior was cheap and not aesthetically pleasing, plus cramped (I'm 6" 3) as the steering wheel only went up and down, not back/forward. There was not the same feeling about the car on the road test, plus the gear shift vibrated, the low down torque was no where near what I thought it would be. But it did go well and is faster, also does not sound as nice as the Brera.

For me it was just faster, no were near enough to think swapping.

I was pleased to get in my Brera :thumbup:

 

[clivemajor]

Ive got full decat on mine (manifolds and secondaries)

Im thinking of putting the secondaries back in though as the system seems to be lacking back pressure so struggles a bit under 2000rpm and even remapping hasnt helped in this respect.

It does fly at the top end though and the rasp that comes out of the pipes is something to behold. Anyone who says these GM motors cant sound as good as a Busso havent heard mine!

Thanks Aeroresh

Does it pass the MOT? This is my main worry e.g. Decat the manifolds and then find I can't MOT it.

Also could I ask how much you were charged to decat the manifolds, and are the Autodelta's?

Thanks

 

[Aeroresh]

Thanks Aeroresh

Does it pass the MOT? This is my main worry e.g. Decat the manifolds and then find I can't MOT it.

Also could I ask how much you were charged to decat the manifolds, and are the Autodelta's?

Thanks

It shouldnt pass technically as there should be a visual check on the cat but it was fine on emmisions.

Best way is to get your exhaust guy to fab an interchangeable bolt in cat/decat pipe just in case.

Yeah, they're the autodelta headers. Its an engine out job to fit them though. I coordinated it with a clutch change so the cost was offset somwhat. figure on about £600 if just fitting the headers?

 

[clivemajor]

Thanks

I think my plan is as below:

1. Custom cat back system, keeping Prodrive back boxes as these are good right?
2. Vortex chamber, commanderfish reports some good gains on the 2.2
3. After a while custom front pipe and high flow cats (secondary)
4. Then may be the pre-cats

Sounds like a good plan?

Cheers

 

[lizard]

I would start with decat exhaust manifolds and leave OEM secondary cats as they are.

 

[kierenc]

Thanks

I think my plan is as below:

1. Custom cat back system, keeping Prodrive back boxes as these are good right?
2. Vortex chamber, commanderfish reports some good gains on the 2.2
3. After a while custom front pipe and high flow cats (secondary)
4. Then may be the pre-cats

Sounds like a good plan?

Cheers

how did this go?