Sports cats - worth it?
#1
Sports cats - worth it?
I have a 2006 STI (2.5L) which has been remapped to 344bhp and 382lb ft.
I have the standard downpipe in place and a decatted mid section, like the PPP set up. Car is otherwise standard apart from a panel silter and RCM fuel pump.
I'm wondering if it might be better to replace the downpipe and the decat pipe with 200 cell sports cats.
So my question is this:
What's better for performance, a single OE cat in the downpipe or 2 x 200 cell sports cats (one in the downpipe and one for the mid cat)??
Strange question perhaps but emissions regs over here in Switzerland force creative thinking...
I have the standard downpipe in place and a decatted mid section, like the PPP set up. Car is otherwise standard apart from a panel silter and RCM fuel pump.
I'm wondering if it might be better to replace the downpipe and the decat pipe with 200 cell sports cats.
So my question is this:
What's better for performance, a single OE cat in the downpipe or 2 x 200 cell sports cats (one in the downpipe and one for the mid cat)??
Strange question perhaps but emissions regs over here in Switzerland force creative thinking...
#2
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im running the same setup as you and my downpipe has just failed. got a h&s sportscat downpipe going on friday.
do you need to have 2 cats ? if so a sports cat downipe and the std centre cat would prob be the easiest option.
do you need to have 2 cats ? if so a sports cat downipe and the std centre cat would prob be the easiest option.
#7
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I have a 2006 wrx 2.5L with vf48 turbo, panel filter, Walbro fuel pump, STI intercooler etc with a 200 cel sports cat downpipe and resonated mid section. Only 1 sports cat and the car made 334bhp & 381lb/ft.
I’d say stick with your current setup if you made that power. Little to be gained!
I’d say stick with your current setup if you made that power. Little to be gained!
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#8
thanks for the feedback, very interesting - sounds like there's basically no massive difference between the standard dp and the sports cat.
Sure we're running different maps but it doesn't sound like there's much difference either way.
I'm on a vf43, not sure if that produces more or less power than the 48?
Do you find you are still able to hit EU4 emissions with the sports cat?
My figures are from a road dyno (Bob Rawle), not sure if that makes a difference?
Sure we're running different maps but it doesn't sound like there's much difference either way.
I'm on a vf43, not sure if that produces more or less power than the 48?
Do you find you are still able to hit EU4 emissions with the sports cat?
My figures are from a road dyno (Bob Rawle), not sure if that makes a difference?
#9
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VF43 and VF48 are basically the same turbo. VF48 is the updated version but so similar. Expect them to make same power / torque.
My car has just flown through its MOT with the sports cat exhaust on so no problems there.
My figures were from rolling road but I think Bobs road dyno software is also pretty accurate.
My car is running a 2.5” system still but 3” 200 cel sports cat downpipe tapering to 2.5” at the mid pipe flange. The turbo was mapped with a 3 port boost solenoid to 1.35bar max as it had slight crack in wastgate housing. Yours may be mapped to more boost and making more power. Every car is different but sounds like yours is making good power on the current setup to be honest. Only way you would increase that by much would be to decat completely.
My car has just flown through its MOT with the sports cat exhaust on so no problems there.
My figures were from rolling road but I think Bobs road dyno software is also pretty accurate.
My car is running a 2.5” system still but 3” 200 cel sports cat downpipe tapering to 2.5” at the mid pipe flange. The turbo was mapped with a 3 port boost solenoid to 1.35bar max as it had slight crack in wastgate housing. Yours may be mapped to more boost and making more power. Every car is different but sounds like yours is making good power on the current setup to be honest. Only way you would increase that by much would be to decat completely.
#10
cool, thanks for the info.
Would you be able to send me the emissions specs of your car from the MOT? I'm trying to work out if I'm going to be able to get my car through the testing over here and it sounds like we're running a pretty similar set up so if your sports catted car got through I should have no trouble... (in theory!)
Would you be able to send me the emissions specs of your car from the MOT? I'm trying to work out if I'm going to be able to get my car through the testing over here and it sounds like we're running a pretty similar set up so if your sports catted car got through I should have no trouble... (in theory!)
#12
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Mine was a Cobra exhaust system with 200 cel sports cat, could always ask them if a sports cat of this type is likely to pass American standards and what sort of emissions testing results they have? (Just in case I can’t find my results fast enough). lol
http://www.cobrasport.com/
http://www.cobrasport.com/
#15
ok, thanks for the advice.
When the MOT is carried out in the UK, what specifications are the emissions values measured against? Is it just a measurement of the emissions at idle?
I'm trying to figure out if the car is really still EU4 compliant even after a remap and removal of the 2nd cat...
When the MOT is carried out in the UK, what specifications are the emissions values measured against? Is it just a measurement of the emissions at idle?
I'm trying to figure out if the car is really still EU4 compliant even after a remap and removal of the 2nd cat...
Last edited by MadUsa1; 02 January 2012 at 02:21 PM.
#16
Hang on, if the STI can meet EU4 emissions standards with only the cat in the downpipe, why did Subaru fit the second cat in the mid pipe as well?
The JDM STI's only have the cat in the downpipe so they could've used the same decat mid section from that.
The RB320 only has a cat in the downpipe and that seems to still comply to EU4. Any ideas???
The JDM STI's only have the cat in the downpipe so they could've used the same decat mid section from that.
The RB320 only has a cat in the downpipe and that seems to still comply to EU4. Any ideas???
#19
super!
so essentially in the UK the MOT only tests CO and HC and both limits are massively high so you'll quite easily get through.
and you failed after the mods??
so essentially in the UK the MOT only tests CO and HC and both limits are massively high so you'll quite easily get through.
and you failed after the mods??
#22
yeah massive difference in emissions. Hmm, bit worried now!
Thanks for posting these up, very interesting to see.
It seems the RB320 is still EU4 and that doesn't run a mid cat so perhaps I'll be ok.
Thanks for posting these up, very interesting to see.
It seems the RB320 is still EU4 and that doesn't run a mid cat so perhaps I'll be ok.
#23
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I thought the PPP kit as fitted to the RB320 is essentially a post registration mod. so it is classified differently to EU4 as hinted on the Prodrive docs
www.prodrive.com/up/06MY%20STi%20PPP.pdf
#25
I have a 2006 STI (2.5L) which has been remapped to 344bhp and 382lb ft.
I have the standard downpipe in place and a decatted mid section, like the PPP set up. Car is otherwise standard apart from a panel silter and RCM fuel pump.
I'm wondering if it might be better to replace the downpipe and the decat pipe with 200 cell sports cats.
So my question is this:
What's better for performance, a single OE cat in the downpipe or 2 x 200 cell sports cats (one in the downpipe and one for the mid cat)??
Strange question perhaps but emissions regs over here in Switzerland force creative thinking...
I have the standard downpipe in place and a decatted mid section, like the PPP set up. Car is otherwise standard apart from a panel silter and RCM fuel pump.
I'm wondering if it might be better to replace the downpipe and the decat pipe with 200 cell sports cats.
So my question is this:
What's better for performance, a single OE cat in the downpipe or 2 x 200 cell sports cats (one in the downpipe and one for the mid cat)??
Strange question perhaps but emissions regs over here in Switzerland force creative thinking...
Its an RB320 so has a prodrive pump
Last edited by chopperman; 06 December 2011 at 10:33 PM. Reason: added to post
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