Exhaust, does size count?
08 May 2010, 04:08 PM
#1
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Exhaust, does size count?
Hi,
I have an 02 bugeye with a PPP, i want to replace the the downpipe and centre section cats, and hopefully keep my prodrive back box.
So I can get a 3" decat downpipe the narrows to 2.5" at the flange and a 2.5" decat centre section so that connects to my prodrive backbox, is this set up good enough or do I need 3" all the way thru and replace the back box??
thanks
I have an 02 bugeye with a PPP, i want to replace the the downpipe and centre section cats, and hopefully keep my prodrive back box.
So I can get a 3" decat downpipe the narrows to 2.5" at the flange and a 2.5" decat centre section so that connects to my prodrive backbox, is this set up good enough or do I need 3" all the way thru and replace the back box??
thanks
08 May 2010, 04:14 PM
#2
Thats what most of the down pipes do unles they state that they have a 3" flunge on them. I have a H&S full system and that is what it does and i am running about 340 - 350 bhp.
08 May 2010, 04:15 PM
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You can do what you want and it will work okay. Keeping the 2.5" exhaust will limit your power, but that limit is probably beyond what your current setup can deliver so no real concern. You can buy an adaptor to do this if you go for a full 3" downpipe and centre (often come as a one piece anyway) and then you'll be future proofed - just whip off adaptor and you have a 3" flange
08 May 2010, 04:29 PM
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You can do what you want and it will work okay. Keeping the 2.5" exhaust will limit your power, but that limit is probably beyond what your current setup can deliver so no real concern. You can buy an adaptor to do this if you go for a full 3" downpipe and centre (often come as a one piece anyway) and then you'll be future proofed - just whip off adaptor and you have a 3" flange
The only trouble is I can find a 3" centre section, any ideas?
08 May 2010, 04:32 PM
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Speak to Exhausts UK about their Cobra exhausts. I have their 3" decat and centre, mated to my blitz backbox. Little unreliable, and you certainly get what you pay for on terms of quality, but I've had worse
Check out the trader section for their contact details.
Check out the trader section for their contact details.
08 May 2010, 04:32 PM
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Speak to Exhausts UK about their Cobra exhausts. I have their 3" decat and centre, mated to my blitz backbox. Little unreliable, and you certainly get what you pay for on terms of quality, but I've had worse
Check out the trader section for their contact details.
Check out the trader section for their contact details.
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08 May 2010, 04:38 PM
#8
I've got a Kakumei 3" downpipe and middle section mated up to a TSL GrpN back box. Because of the 3" flanges not mating up to the 2-5/8's backbox flanges some cutting and welding had to be done but it works well. A slightly narrower back box pipe may help a little bit with torque but not so much that i think you would notice. Sounds nice though and not to loud.
It won't limit your power output enough either so that you'd notice. Should still be good for 500bhp if that's where you're heading but you'll need to change the headers and uppipe to something more appropriate.
Just make sure you remap for it as you'll experience some overboosting due to the quicker/stronger turbo spoolup and no doubt you want some more power from it however, it might not be too bad and you might get away with it if you don't remap. You won't gain much extra power though.
It won't limit your power output enough either so that you'd notice. Should still be good for 500bhp if that's where you're heading but you'll need to change the headers and uppipe to something more appropriate.
Just make sure you remap for it as you'll experience some overboosting due to the quicker/stronger turbo spoolup and no doubt you want some more power from it however, it might not be too bad and you might get away with it if you don't remap. You won't gain much extra power though.
Last edited by scoobiewrx555; 08 May 2010 at 04:40 PM.
08 May 2010, 05:29 PM
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I've got a Kakumei 3" downpipe and middle section mated up to a TSL GrpN back box. Because of the 3" flanges not mating up to the 2-5/8's backbox flanges some cutting and welding had to be done but it works well. A slightly narrower back box pipe may help a little bit with torque but not so much that i think you would notice. Sounds nice though and not to loud.
It won't limit your power output enough either so that you'd notice. Should still be good for 500bhp if that's where you're heading but you'll need to change the headers and uppipe to something more appropriate.
Just make sure you remap for it as you'll experience some overboosting due to the quicker/stronger turbo spoolup and no doubt you want some more power from it however, it might not be too bad and you might get away with it if you don't remap. You won't gain much extra power though.
It won't limit your power output enough either so that you'd notice. Should still be good for 500bhp if that's where you're heading but you'll need to change the headers and uppipe to something more appropriate.
Just make sure you remap for it as you'll experience some overboosting due to the quicker/stronger turbo spoolup and no doubt you want some more power from it however, it might not be too bad and you might get away with it if you don't remap. You won't gain much extra power though.
Thats pretty much what I wanted to hear thanks.Yeah I have been told its best to get a remap done, once i save the cash up!! Im not looking for tons on bhp really, just want things running nice
Is there any real gain in changing the manifold?
08 May 2010, 05:58 PM
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At around 360-400 bhp you will benefit from a full 3" exhaust, I did !
On a nearly std. car you may adversely affect turbo spool by adding tubular manifolds, harvey does ported items that are good for most road cars, IMHO
HTH
dunx
On a nearly std. car you may adversely affect turbo spool by adding tubular manifolds, harvey does ported items that are good for most road cars, IMHO
HTH
dunx
Last edited by dunx; 08 May 2010 at 05:59 PM.
08 May 2010, 07:58 PM
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