Exhaust advice - 2.5" down from 3

[lmoengnr]

6" bodied 400 cell cats

Are they Euro 4 Commodore cats?

 

[Ginger Beer]

Are they Euro 4 Commodore cats?

Nope after market, I also made a mistake in the size, the body is only 5"

https://racecraftaus.com/products/catalytic-converter-universal-400cpsi-euro5?variant=39439772680305

My opinion is keep the exhaust as clean as reasonably practicable for a street car

I also noticed no power loss from going from a Euro 2 high flow to a Euro 4 high flow, on the dyno at Autotech it needed nothing done to the tune, it made exactly the same power, and the car ran exactly the same on the street and strip

Making the car emissions compliant was a 100% requirement, the Euro 2 failed failed, horribly, the Euro 4 passed easily on 98 with the new cats the only change

Maybe it would be noticeable if I was making big power, but 2 of these cats easily flow the 500hpatw that the car makes

 

[lmoengnr]

Nope after market, I also made a mistake in the size, the body is only 5"

https://racecraftaus.com/products/catalytic-converter-universal-400cpsi-euro5?variant=39439772680305

My opinion is keep the exhaust as clean as reasonably practicable for a street car

I also noticed no power loss from going from a Euro 2 high flow to a Euro 4 high flow, on the dyno at Autotech it needed nothing done to the tune, it made exactly the same power, and the car ran exactly the same on the street and strip

Making the car emissions compliant was a 100% requirement, the Euro 2 failed failed, horribly, the Euro 4 passed easily on 98 with the new cats the only change

Maybe it would be noticeable if I was making big power, but 2 of these cats easily flow the 500hpatw that the car makes

I know of 3 E series Maloo's with factory exhausts, running Heartbeat superchargers that vary between 390-400 RWKW, and comply with emissions.

 

[RevNev]

I know of 3 E series Maloo's with factory exhausts, running Heartbeat superchargers that vary between 390-400 RWKW, and comply with emissions.

What's acceptable as emission compliance seems to vary a bit from state to state. In SA, you must retain the OEM cats in the original location, headers and exhausts are free other than extreme noise. If the cat setup is modified, they have to pass a full ADR emission test certified by a specific test station. Interestingly, if you pipe stock cats, they don't even look at it and assume it's unmodified even if they're choking on exhaust fumes!

 

[Ginger Beer]

In NSW you can be reported by anyone, or instructed by the RMS, or on a police defect for a IM240 test

 

[RevNev]

In NSW you can be reported by anyone, or instructed by the RMS, or on a police defect for a IM240 test

How often does that happen with the mass volume of modified Commodores?

In SA, exhausts are an issue at rego inspections, interstate vehicle applications for SA rego or defect notices for something else. On the road, the cops generally only target excessively noisy exhausts and unless you get caught doing something stupid, they don't bother too much with modified cars that aren't radical.

 

[dassaur]

Nope after market, I also made a mistake in the size, the body is only 5"

https://racecraftaus.com/products/catalytic-converter-universal-400cpsi-euro5?variant=39439772680305

My opinion is keep the exhaust as clean as reasonably practicable for a street car

I also noticed no power loss from going from a Euro 2 high flow to a Euro 4 high flow, on the dyno at Autotech it needed nothing done to the tune, it made exactly the same power, and the car ran exactly the same on the street and strip

Making the car emissions compliant was a 100% requirement, the Euro 2 failed failed, horribly, the Euro 4 passed easily on 98 with the new cats the only change

Maybe it would be noticeable if I was making big power, but 2 of these cats easily flow the 500hpatw that the car makes

That size cat will take away another 1 inch of ground clearance which I am already stretched on!
If the entry/exit were offset I would definitely give it some good consideration.

I also don't quite understand why the euro 5s are allegedly hi flow and the 4s are not. If the 5s are a 5 inch body that is 400 cel, then there will be the same catalyst material as a proportion to the 4 inch bodied 400 cel!

 

[lmoengnr]

That size cat will take away another 1 inch of ground clearance which I am already stretched on!
If the entry/exit were offset I would definitely give it some good consideration.

I also don't quite understand why the euro 5s are allegedly hi flow and the 4s are not. If the 5s are a 5 inch body that is 400 cel, then there will be the same catalyst material as a proportion to the 4 inch bodied 400 cel!

The Euro 5 OEM cats are physically smaller than the Euro 4 OEM cats.
I remember reading somewhere that the Euro 5 cats are 600cpi compared to 400cpi on the Euro 4's.
I have Sureflow headers and large body 100cpi Ballistic cats on my Maloo, they sit in the same position as the factory cats and don't effect ground clearance.
I also know VicPol will defect you, if they look under the car and see the cats positioned near the end of the gearbox.

 

[dassaur]

The Euro 5 OEM cats are physically smaller than the Euro 4 OEM cats.
I remember reading somewhere that the Euro 5 cats are 600cpi compared to 400cpi on the Euro 4's.
I have Sureflow headers and large body 100cpi Ballistic cats on my Maloo, they sit in the same position as the factory cats and don't effect ground clearance.
I also know VicPol will defect you, if they look under the car and see the cats positioned near the end of the gearbox.

My cats end where the factory ones do.

 

[RevNev]

That size cat will take away another 1 inch of ground clearance which I am already stretched on!

I don't think Ginger Beer's car is a VE/VF and if it's on the VT/VZ platform, the floor-pan is raised to accommodate the OEM cats towards the rear of the gearbox. There's no room for 5" diameter cats on a VE/VF other than in the OEM location.

I also know VicPol will defect you, if they look under the car and see the cats positioned near the end of the gearbox.

Particularly when someone buys an interstate VE/VF with long tube headers and takes it for an SA rego inspection, they'll issue a work order to return the cat setup to stock. You can have HSV headers or Pacemaker shorties and any exhaust system that isn't too loud, but the stock cats must remain in the stock location to pass the inspection. They'll seem to pass VE or VF1 Euro 4 cats on MY17 VF2's that should be Euro 5 no problems.