Dave1980

hello

i am booking my car in at local performance centre to get a decat and some new springs next week.

when i asked about the decat they said there are two types. A normal decat and a waistgate bypass decat.

can someone elaborate on the waistgate bypass and tell me the advantages. Not much price difference between the two but apparently this one will make it go a lot better.

if it makes any difference this is on an my93 wrx

thanks

p.s. - p.s. lewis this is a genuine question so avoid ruining it when you are trolling for threads to ruin.

RB5_245

Wastegate by-pass??? whatever it is, it's technically inacurate as the wastegate IS a turbine by-pass..

By-pass the by-pass?? sounds like some sort of government initiative

Probably means twin dump or single dump downpipe. I think the general concensus is to go for the single dump bellmouth type as it's just as good at the top end but provides better midrange (could be better at the top and just as good mid?? don't remember).

Technically the twin dump should be better but in real life this doesn't seem to be the case, the people with them seem to notice an imediate improvement on swapping to single one. I've never heard anyone say the reverse.

Dave

Dave1980

interesting i will have to investigate more, just after a bit more mid range.

RB5_245

What sort of power are you going for, smaller for better pick up, bigger ie 3" right through if you're heading over 300bhp-ish.

I think going for the open neck would be my choice in your situation.

Dave1980

well looking for around 300bhp ideally, have a 260hp ecu in there at the minute. just want something to give a bit more response and a bit more go.

Dave1980

is the general opinion to go for the lesser of the two decats as its more useable?

RB5_245

Don't know what you're getting at there, nut the gain will be greater by removing the downpipe cat than the center cat.