BMW M5 Forum and M6 Forums banner

1 - 16 of 16 Posts

·
Registered
Joined
·
3,176 Posts
Do they replace the primary or secondary set of cats?


Cheers ///

If you're referring to SuperSprint, then its the 2ndary.

The Race cats needs to be installed with the SS headers.

The SS headers replaces the one piece exhaust manifold/primary cats.

Isn't that what they did on your car?
 

·
Registered
Joined
·
1,047 Posts
Discussion Starter #3
If you're referring to SuperSprint, then its the 2ndary.

The Race cats needs to be installed with the SS headers.

The SS headers replaces the one piece exhaust manifold/primary cats.

Isn't that what they did on your car?
No, I do not have race cats with my headers. Are they worth the 4g?


Cheers ///
 

·
Company Representative of RPI Power
Joined
·
3,395 Posts
The Magnaflow/Carsound 599xx line is the best flowing on the market. The 3" 59929 was tested (1000 cfm range @ 28" of H2O) to flow to 598 CFM.



The Random Technology 3" metal matrix cat (not the ceramic version) is close at around 575 CFM.

The 59926 uses the same body as the 59929, but with 2.5" inlets & outlets, which is the size we'd use.

They're not expensive either, at under $90 per (we'd need 2 on the M5).

http://www.eadperformance.com/catalog/product_info.php?cPath=42_75_77_78&products_id=194

That's $180 plus the labor of welding for the best cats on the market. Much better than $4000, IMHO.
 

·
Registered
Joined
·
902 Posts
There are substantial gains to be had from replacing the stock secondary cats; whether or not it's worth it to go with the SS part is a different story. If you know a quality custom exhaust shop, then it would probably make sense to at least talk to them about your options.
 

·
Registered
Joined
·
1,535 Posts
The Magnaflow/Carsound 599xx line is the best flowing on the market. The 3" 59929 was tested (1000 cfm range @ 28" of H2O) to flow to 598 CFM.

The Random Technology 3" metal matrix cat (not the ceramic version) is close at around 575 CFM.

The 59926 uses the same body as the 59929, but with 2.5" inlets & outlets, which is the size we'd use.

They're not expensive either, at under $90 per (we'd need 2 on the M5).

http://www.eadperformance.com/catalog/product_info.php?cPath=42_75_77_78&products_id=194

That's $180 plus the labor of welding for the best cats on the market. Much better than $4000, IMHO.
Wow, that's impressive. Do you know how it performs with respect to emissions?
 

·
Registered
Joined
·
3,176 Posts

·
Company Representative of RPI Power
Joined
·
3,395 Posts
Wow, that's impressive. Do you know how it performs with respect to emissions?
That's a bit harder to say, since emissions really depends on the cats & the car.

This being said, they're still 300-cell metal matrix cats, which is rather high. Reducing the cell count reduces the emissions related effectiveness (and also reduces the longevity).

A lot of Porsche 996TT aftermarket exhausts use 100-cell, and still pass emissions. I would guess that your typical 996TT's engine is more poluting than the M5/M6's S85, especially considering how much richer they tend to run.
 

·
Registered
Joined
·
1,535 Posts
That's a bit harder to say, since emissions really depends on the cats & the car.

This being said, they're still 300-cell metal matrix cats, which is rather high. Reducing the cell count reduces the emissions related effectiveness (and also reduces the longevity).

A lot of Porsche 996TT aftermarket exhausts use 100-cell, and still pass emissions. I would guess that your typical 996TT's engine is more poluting than the M5/M6's S85, especially considering how much richer they tend to run.
Sounds logical to me. I think you've found my cats if I ever decided to get headers. Thanks. :cheers:
 

·
Registered
Joined
·
1,047 Posts
Discussion Starter #15
The Magnaflow/Carsound 599xx line is the best flowing on the market. The 3" 59929 was tested (1000 cfm range @ 28" of H2O) to flow to 598 CFM.



The Random Technology 3" metal matrix cat (not the ceramic version) is close at around 575 CFM.

The 59926 uses the same body as the 59929, but with 2.5" inlets & outlets, which is the size we'd use.

They're not expensive either, at under $90 per (we'd need 2 on the M5).

http://www.eadperformance.com/catalog/product_info.php?cPath=42_75_77_78&products_id=194

That's $180 plus the labor of welding for the best cats on the market. Much better than $4000, IMHO.
Damn Noble, good work.:applause:

Cheers ///
 
1 - 16 of 16 Posts
Top