is this usual behaviour from the S2????

[R31LLY]

hello all...
yesterday i have a 3" bore exhaust fitted to my car along with a decat pipe, since then my car has boost spiked, missfires, cherped like a rally cars wastegate and ive had boost flutter. is this what happens to everyones untill they get a remap or what?

also just so you know, i do not have my old exhaust to put back on for now :-(

(i know not to drive the car with any throttle on etc as it will be running lean now on boost which is defo not a good thing, my car is booked in for a chip next month. this should fix it right??? )

[AndyP]

I think the boost spike is normal as the turbo should spool up much quicker with a 3" exhaust and no cat.

Did you make it yourself or get it done professionally?

[R31LLY]

got it done professionaly at longlife exhausts leeds,

[driftin jo]

Did your car run slow before ?
I'm thinking your cats my have been blocked and now the boost is coming on much faster. It could be due to waste gate control adaptation. Try resetting the ECU by pulling the fuses or disconnecting the battery.
Even if I'm wrong this is not normal at all and you don't need a remap.

[R31LLY]

yes my car was slow before it was running 15sec 1/4 miles last month, with a k24 hybrid on and i believe the standard car should do it in 14.5secs.

[driftin jo]

why do you think it would be running lean ?
is it chipped or standard ?

[R31LLY]

would a stiffer or softer wastegate spring help in anyway?

i have a rs2 maf sensor on the car but i dont think this will change too much

[driftin jo]

i'm getting deja vous now.

[R31LLY]

the car is standard except the hybrid turbo untill 23rd June

[R31LLY]

i think it will be lean cos of something i read about the car not getting enough fuel as it misfires at 4000rpm and splutters and cuts out if you drive slow it seems like is running normal, if you let off the throttle before 14psi its fine but if you dont i spikes to 30psi and chatters like a rally car, ive now learnt how to get by with my car till i stop this problem

[prj]

If you spike it to 30 psi on stock injectors you will bend your rods and eventually blow up your engine.
Your wastegate should be stock, with stock spring.

You should not spike to 30 psi boost on that turbo, no matter your exhaust.
Is your N75 connected correctly? It really sounds like you don't have the lower chamber connected properly.

When they were working on your car, no doubt they unbolted and disconnected everything, maybe they connected it wrong?

[R31LLY]

yes they said they took all the airbox off ill go check that, im sure my n75 is plugged in right i dont think the plug can go in the wrong way round can it? ill go see, would opening the d.v to vent some gases will help any?

[R31LLY]

airbox is all screwed up right, n75 is in and on right also looks to be on in the right way round,

[S2central.net]

Two suggestions...

1 - reset the ecu and see if/how it adapts

2 - unplug N75 and see how boost behaves. Shouldn't max much more than 0.4bar on stock spring

3 - Get a decent wb afr installed - that is the only way to analyse mixture properly

4 - check the plumbing for n75 to make sure it is correct... Bottom pipe goes to the turbo and the outer pipe goes to WG

[S2central.net]

Oh and yeah 30psi will kill your car as it is - something mechanical is preventing the ecu from keeping things in control.