Boost Controllers?

[SpeedySub]

Ok, so have been trolling the internet reading info on turbos and boost controllers and wanting a bit of help determining whether I need one and if so whats good.

So the car is 91 RS legacy with TD05 and V4 wrx Z4 ecu. No mods except for exhaust.

1. without mods do I need a boost controller - I have read that a manual boost controller is better than the stock one as it allows to wastegate to remain fully closed to full boost is achieved as what Ive read the factory solenoid will start open a little before full boost.

2. Is a MBC safe to use? how easy to set up? I have a boost gauge so I can see whats happening.

3. Is there a risk of boost spikes?

4. Does a boost controller need a tune to work properly?

 

Im not wanting to up the boost at this point, but most things Ive read say ditch the factory solenoid.

Im totally new to the world of turbos and wanting to increase my knowledge before I buy anything or do anything to ruin the car. It does seem there are varying opinions about MBCs and EBCs.

 

Any/as much info on whats required, if I should get one, am I an idiot for suggesting it, any comments please.

 

Thanks

[slystiguy]

I run an electronic one on my bc, would happily use either manual or electronic. Boost spikes can be for a number of reasons but I doubt at those sort of levels it's much of an issue. Unplugging your solenoid will bring up a CEL.  I would suggest before you go turning the boost up you grab an AFR gauge and check the engine isn't leaning out. Plus they're a good tuning tool to have for future upgrades/compatible with link. And probably good to do the fuel pump wiring mod and make sure it has a upgraded pump in it. Good time to check out condition of coils/plugs too as the more boost you have the more likely you will be to have spark issue up in the rev range. Those ecu run like 12.5 psi anyway? And cuts at 15ish so there's not much room for tweaking. Generally putting a couple psi into a factory tune won't hurt it but you might not get much of a power increase. Make sure you run good fuel so your det chances are reduced. 

 

 

P.S You need to do a garage thread so we know what mods your car has

 

 

[SpeedySub]

Yeah I really need to set up my garage thread (might do that now).

 

Not really wanting to up the boost as such, Im quite happy with it, but after spending a night reading I wasn't too sure if I needed one or not.

Im always running 98 in it.

 

[THUNDA]

Been doing the fuel pump wiring mod today, however I dont have the same colour wires as in the guide  nothing is straight forward bleh

 

https://www.dirtyolbc.co.nz/community/topic/906-changing-a-fuel-pump/

 

He says cut a black wire with yellow stripe, ive got a thicker wire at the relay  which is red and black but that is already substantially thicker gauge, and am thinking its power from battery/ignition and if you zoom in you can see he doesnt cut the black with red stripe

 

 

plug at relay has 4 wires

thick one black with red stripe, 2 thin yellows and a thin green with black stripe

 

at fuel pump ive got 5 wires, 3 thin ones which are 2 green and a black, and 2 thick ones which are blue with yellow stripe and black

 

 

is it possible subaru changed the loom when my car was made ? (1992 bc5) or am i changing one of the thin wires to a thick one

 

[Guest]

Just get a $5 test light from repco or whoever. Easiest way to find out what wires are what.

[THUNDA]

Sorted it, from the relay in my car its a thick black with red stripe which heads to the fuel pump - but changes colour half way at another plug

at fuel pump plug its a thick blue with yellow stripe, ground is thick black which heads back towards the relay but goes somewhere else, at relay there is no black wire to indicate a ground