external wastegate?
 

i have just put an external wastegate on my 94 sti (rs200 replica, look in projects), now its on what do i do with the bottom valve in the pic, the vaccum pipes went to the turbo housing and the actuator,

http://i51.photobucket.com/albums/f3...Picture007.jpg

cheers phil.:thumb:

anyone...

Apologies for the late reply - see her for where all the appropriate vac lines go to/come from (courtesy of Scott T's Polar Performance website)...


http://www.polarperformance.co.uk/Boost_Control.jpg

hi, thanks for the reply, but the thing is, now the external wategate is on the exhaust, it has a pipe going from the turbo to the wastegate making the bottom solenoid redundent, so what should i do with it?

I would have thought you need to disconnect the vac line at the external wastegate end and move it to the top of the BCS (where it says "turbo outlet nipple"). Then a vac hose goes from the bottom-side nipple of the BCS ("actuator connection"), and back to the W/G.

What you've done is still maintained the connection from turbo to W/G but have looped in the the BCS so that the ECU can intervene to modify the boost levels - either more boost or less boost - as it sees fit. Don't quote me on this though - it's just that's how I thought it worked. :wonder:

Also, at the very bottom, you have no hose (which would go the airbox resonator after the MAF... or vents to atmosphere if a CAIK is fitted). It also has a small brass restrictor pill in which is designed to maintain the correct level of level of baseline boost. Without it, I think you may suffer overboost :wonder:

How do you control the boost if there is no solenoid to bleed off pressure whilst accelerating ? Direct connection means any boost will start to open the wastegate, in general you have just added a different part that needs connecting the same way, and then re-mapping for correct operation.

I take it that your (new) turbo not have an integral wastegate ?

All imho

dunx

If the BCS is not looped in between the turbo and W/G, then the ECU obviously has no electro-mechanical means to control the W/G actuator to regulate boost pressures. So all that would be available is just the std boost rating of the external W/G's actuator setting - neither more nor less - as no boost can be bled away so as to allow more effective pressure at the W/G before opening, therefore more boost pressure. (At least it'd be safe lol).

I'm no expert but does a TD 06 not have a wastegate built-in ? What are these external units set to ? Could be 3 bar ? I don't know....

dunx

External W/Gs are massive aren't they. As the large turbos require them to be, hence why they're remotely mounted. They sure do look like they would have very stiff diaphragms :wonder:

hey happy new year to you all, my set up is virtually the same as the on in the pic and you can see its piped straight from the turbo to the wastegate, im sure the wastegate in the pic is adjustable as mine is, thats how i thought it is supposed to be done, sorry for confusing everyone about the bcs but i would have thought its not doing anything with this setup, so what to do with it?
http://i51.photobucket.com/albums/f3...subenigine.jpg

anyone?

Compressor housing outlet into a 'T' piece, one run then goes to the side port of the Ex WG, the other run (from the 'T') to top port of the BCS (Turbo Outlet Nozzle in the above picture).

The side port of BCS (Actuator Connection, above pic) runs to the Top Port on the Ex WG.

If you are running the car in, or pre-remap than I strongly suggest just using a vacuum pipe run from the compressor housing to the side port of the wastegate only. This will give you spring pressure.

Use good quality hose, keep the runs as short as possible and well away from heat sources :thumb:


Jase.

Jase, FTR are those connections the same for a conventional integrated turbo's W/G actuator? Does the integrated W/G have two ports on it then, like the external W/G?

thanks jase, its much clearer now, it will be pre remap so ill run a pipe from the turbo housing straight to the wastegate, and pipe it to the bcs when remapping, thanks again, phil.

Slightly different - Compressor cover to 'Compressor Outlet Nipple' and then 'Actuator Connection' to WG. This way you can 'bleed' off pressure going to the WG to achieve a higher boost pressure than what the actuator/WG is rated for.

Most external WG's have 2 ports so you can 'pressurize' both sides of the diaphram. Stock/integral WG's only have the one port.


Jase.

Cheers. That's what I thought (hence my earlier post; albeit 'wrong' advice for the OP's ext. W/G).

Regarding later 2-port BCS on the later cars; why did they change it from the more controllable 3-port to the 2-port? Is it something to do with the early ones' bottom vac line (with the restrictor pill to control BCS's baseline boost) going into the intake i.e. not required anymore? If so, why?

oooh now youve confused me, mine has two nipples on the wg, so do i use a T piece to the bcs/side port on the wg then to the wg or do it go straight to the bcs and back to the wg, sorry, phil.

The correct hook-up info is described in Jase's post # 12 for your external wastegate - he mentions about the two W/G nipple connections, etc. :) :thumb: (please ignore my own ramblings :cuckoo: :rolleyes:)

ha ha, ok thanks.:thumb:

He's getting there, I'm glad mine's integral !

Good luck, with an impressive project.

dunx