today we had a cooper s in 2009 that had been to a so called tuning house nearby and had bigger intercooler fitted bigger injectors dump valve pretty blue pipe work hmmm take it from me black for gobabygo rule of thumb as handles heat better and a mother of a remap and as requested by owner wanted pops and bangs from exhaust which is very much possible and is ok when done correctly ie can have some right big flames on and off over run and work fine like it,
so what you dont do is all of the above and then leave the cat in place and leave 02 sensors controlling the fuel air mix trim, what happens is to get pops and bangs more fuel is used for long duration to allow unburnt fuel and air mix to enter the exhaust on overlap scavenge where it ignites a bit like a furnace ie cats max temp 1000c on the very top end by adding fuel at that time it pushes the temps well north of that is a restricted area and just explodes the cat over time,, also its melts the 02 sensors and puts massive heat and pressure on turbo and engine etc , so correct way should be decat ie keep the cat looking standard and sleeve it inside with a straight pipe this will pass mot for a start, then on on the remap you must map the upstream sensor value parameters different to the down stream sensor cant tell you these figures as part of the mapping and depends on the car etc, when this is done the whole system breaths correctly etc, this guy spent £1700 on this car to make 300bhp and all he got was a hot engine that oil light came on, 10 miles per gallon and undrivable,, after he had got black magic performance centre ie john to sort it all out and do the job correctly on that level car was totally different and so fast,,, honestly be ware there are people out there that can order mod parts from a book and bolt it on but the devil is on the detail getting it all to play right and out of the box as such or before its given back to customer,, the above is very common on petrol tuned cars that run cats for emissions and wont cope with to much non stop heat that remaps and pops and bangs cause, done a ford focus rs turbo other day same thing this one just melted the cat funny enough from same place, the customer rang them and told them about it,, their answer was ho sorry we have had a few like that hmmm that's not right, and did not ask to see car again to sort it or at least find out if was their doing... naughty is what that is, anyone want a good honest garage in southwest or remap or timing chain done etc give john a call
so what you dont do is all of the above and then leave the cat in place and leave 02 sensors controlling the fuel air mix trim, what happens is to get pops and bangs more fuel is used for long duration to allow unburnt fuel and air mix to enter the exhaust on overlap scavenge where it ignites a bit like a furnace ie cats max temp 1000c on the very top end by adding fuel at that time it pushes the temps well north of that is a restricted area and just explodes the cat over time,, also its melts the 02 sensors and puts massive heat and pressure on turbo and engine etc , so correct way should be decat ie keep the cat looking standard and sleeve it inside with a straight pipe this will pass mot for a start, then on on the remap you must map the upstream sensor value parameters different to the down stream sensor cant tell you these figures as part of the mapping and depends on the car etc, when this is done the whole system breaths correctly etc, this guy spent £1700 on this car to make 300bhp and all he got was a hot engine that oil light came on, 10 miles per gallon and undrivable,, after he had got black magic performance centre ie john to sort it all out and do the job correctly on that level car was totally different and so fast,,, honestly be ware there are people out there that can order mod parts from a book and bolt it on but the devil is on the detail getting it all to play right and out of the box as such or before its given back to customer,, the above is very common on petrol tuned cars that run cats for emissions and wont cope with to much non stop heat that remaps and pops and bangs cause, done a ford focus rs turbo other day same thing this one just melted the cat funny enough from same place, the customer rang them and told them about it,, their answer was ho sorry we have had a few like that hmmm that's not right, and did not ask to see car again to sort it or at least find out if was their doing... naughty is what that is, anyone want a good honest garage in southwest or remap or timing chain done etc give john a call
