another decat question

[harvey197]

a few weeks back i changed my manifold for a second hand one from jms tuning, with the precat deleted, now gives a little pop when engine is cold, been thinking of getting the second cat removed now. is there going to be any big down side? flat spot ect. recently one of my dumdass mates removed all cats, silencers and boxes from his astra Nurburgring and mapped it him self along with a intercooler, throttle body mod, diffrent air box, ect, after about a month he blew it up @ 155mph,

i told him at the time not to mess with the exhaust and that he was messing up the engine back pressure, after taking the head off he found that pistons 2 and 3 were melted and one liner gone.

i know his car has more and just a decat, but i dont want to look like a tit if mine goes bang after lecturing him. lol

So to fully decat or not to? and can i get away with it with out a remap to suit??

 

[Russell]

ur mates vxr wld run alot better with decats but for a clio all u really get is noise and no performance, and yes u get a massive flat spot!!

ps. ive not known a astra vxr to melt a piston! there semi forged already so it was his dodgey map not the exhaust at fault!

 

[harvey197]

okdoke, yeah i call his maps "google maps" a bit mickymouse lol

it was ment to be running like 340 bhp, better off with a pro live map, but no one seams to do them up our way i have been told.
cheers for the input.:thumbup:

 

[Foxspeed]

melting pistons is the mapping and a turbo engine runs with back pressure due to a turbo in the exhaust system...

as for a 197 - its a n/a engine - so you need the easiest route in and the least restriction out (f1 engines dont have any restriction)

alot of reasons for flatspots is due to the engine meeting emission standards etc of many 000s of miles - if both cats are removed it needs mapping to sort it out

no cats = mot fail....

 

[harvey197]

melting pistons is the mapping and a turbo engine runs with back pressure due to a turbo in the exhaust system...

as for a 197 - its a n/a engine - so you need the easiest route in and the least restriction out (f1 engines dont have any restriction)

alot of reasons for flatspots is due to the engine meeting emission standards etc of many 000s of miles - if both cats are removed it needs mapping to sort it out

no cats = mot fail....

yeah the mot is no problem, och i will just leave it, i do like the thought of som pops and bangs tho,

 

[Graeme GTR]

another question on decats hopefully someone can answer. When you see the decats for sale from the likes of Milltek, they have a little off shooting bit of metal in the middle, whats this for?? what goes in there?