I have an Impreza rally car with an Sti4 engine using a VF24 turbo and GEMS ecu. I have a 3 port wastgate control solenoid fitted. There is NO restrictor in the pipe from the compressor housing to the wasgate solenoid valve (or anywhere else for that matter).

Does anyone know if it should be there or not and what it actually does? The car was mapped without it, the guy who mapped it said it wasn't required and would make no difference. If I fit one now will it "bugger up" the mapping?

Thanks,

Martin

 

If it was mapped without and holds the right boost then leave it out. 3 port doesn't need one like the 2 ports do.

 

OK, thanks for that, thats all I needed to know!

Martin

 

If it was mapped without the restrictor then yes, it will bugger up the boost control if you refit one now.

There are 2 places the restrictor was fitted, depending on whether the car originally came with a 2 or 3 port boost control solenoid.

With a 2 port the restrictor (small) was fitting in the pipe from the compressor to the actuator before the t-piece for the solenoid bleed pipe.

With a 3 port the restrictor (larger) was fitted in the pipe from the bottom solenoid connection to the inlet pipe.

Andrew...

[Edited to say - cross posted with someone who has tried many more boost control options that me]

[Edited by AndrewC - 1/19/2004 1:52:55 PM]

 

Thanks Andrew, well as I said mine is a 3 port and the outlet of the solenoid has nothing on it, it just dumps into free space. I noticed that on another Sti4 engine, it uses a 2 port with the T piece like a uk MY00 car.

I think I don't need to worry about it and leave well alone.

Martin

 

STi4 would have had a 2 port originally, but many tuners change to a 3 port as they can give better boost control when setup correctly.

Andrew...

 

Well I must admit, I only used the 3 port because thats what came with all the parts when I built the car (the first engine might be off an Sti3 but looks the same), the second engine I got was piped up like a UK car with the 2 port valve. The first engine had a VF24 turbo, I cant read the number on this one due to corrosion but it looks the same externally.