Exhuast centre section - okay to swap without mapping issues?

[Swanny_UK]

Gents,

I\'ve currently got a stock twins downpipe, 2.5" WGT centre section and a 3" Amemiya dolphin tail as my exhaust setup.  The car\'s running an Apexi Power FC ECU.  I\'ve got a 3" silenced dragon centre section ready to go on, but I was going to fit it when I took the car off the road this autumn for a few new bits.  

My question is - as Ive got the stock downpipe (biggest restriction), do you think that swapping from the 2.5" to the 3" silenced centre section would have any detrimental effect and require tweaks to the ECU map?

[Efinity]

I would of thought that you wouldn\'t need to remap the ecu for exhaust changes below the manifold.

Looking at it logically exhaust gases are a by product of the engines process and are not controlled by the ecu.

Yes initially,when the exhast setup is changed, the ecu would need mapping as the system would be less restrictive and therefore processes, turbo spooling is greatly changed due to the increased volume of exhaust gasses leaving the engine.

Buy for a 0.5" increase in diameter, there won\'t be any noticable alterations to engine performance.

Think I\'m going off on a tandem lol, sorry. To put it simply. You don\'t need to remap the ecu as what you want to do is a small change. But if you are performance nut, tweaking the ecu will prob give you the tiniest, minisculest performance increase that you will not notice, as more exhaust gasses will be leaving the engine so this will slighty effect turbo spooling and exhaust process, but again.....the change is soooooo small that you can do this without tweakig anything.

[trotter]

Just to put the cat amongst the pigeons here......

By increasing exhaust diameter (however slightly) are you not making it easier for exhaust gases to leave the engine? In this case, if you\'re wastegate isn\'t correctly sized would you not risk boost creep? In this case i\'d consider re-mapping, as you would when de-catting.

Apologies if i\'ve got the wrong end of the pointy thing here!

[leefitz]

On the same note as the question, if i was to remove the cat on my standered fd would I need to worry about problems it may cause? Running lean??

[turbotoaster]

On the same note as the question, if i was to remove the cat on my standered fd would I need to worry about problems it may cause? Running lean??

i would imagine so, i went from 283bhp to 326bhp just from putting a decat on with no other changes so id imagine you would run lean.

[leefitz]

and a mapable ecu and a rollin road is the only way to cure it then really. or is tehre a poor mans way about it?

[jackaleks]

and a mapable ecu and a rollin road is the only way to cure it then really. or is tehre a poor mans way about it?

drive off the boost

[leefitz]

no fun in a drifter :mad:

[Aubec]

and a mapable ecu and a rollin road is the only way to cure it then really. or is tehre a poor mans way about it?

Poor man\'s solutio is to put a restrictor plate in before the midpipe with a narrower opening, 2.5" say, to restrict gas flow: kind of defeats the point of the exercise though.  Don\'t risk leaning out on a rotary... that\'s the route to a sudden big bill!

[leefitz]

na,  wont take the chance. see how i get on at the driftin it and if i think i need more power then i will splash out on apexi fc and bits