wastegate control

[gcorky]

hello pepes ,starting to read up on boost control methods as in keeping gate closed till optimum boost?

what are you using -i have ms ,but can it be a case of a pressure switch connected to a solenoid to pressure top of actuator till the switch pressure is met then vent to atmos....i see the likes of fozzymonster talking of rpm and load variable control...

any tips on better methods and parts to use...

cheers

Graham

[Ant]

Graham, you can use two methods of controlling boost, a simple gate solenoid blocking the W/G signal line is the easiest , mapped boost can offer X psi @ Y rpm, or X pis @ Y rpm with Z throttle opening, real pandoras box stuff M8.

if you want control, the on/off method would work with a target boost table, all already in the firmware in 029 and above, but bear in mind its all experimental code, with little or no feedback as yet that I've seen.

what are you wanting to achieve dude ? the fully mapped variable that Fozzy is working towards, or simply the ability to select a target boost level without needing to swop springs in the W/Gate

[gcorky]

hi Ant im trying to hold wastegate closed till boost pressure is met,so yes the static switch/solenoid option looks easy enough,just that Mark baffled me with science with regards to rpm/load based controlled by ms...jesus -gives me a real headache when i try to understand...what are you using or going to with your holset based build?

seems theres a lot more to boost control than just venting the top of the gate....like i was going to.

[e30_Turbo]

What did you decide on the wastegate then Graham?

Mines a Tial 38mm twin port, which is why I'm going for the boost control on MS, this type gives the ability to run positive pressure into both ports and then vent the top one at the desired pressure. This gives the wastegate added zest when opening and closing.

Mark.

[gcorky]

mines a 40 mm (hks knock off lol) twin port ...

i do appreciate you get what you pay for but build aint bad,think toby una has the 50 mm version...


so if my thinking is correct-bear with me...i have but wont need any specific w/g spring or my bleed valve but instead plumb in an air pressure switch (to sense boost pressure)that in turn is controlling an air solenoid that merely opens up and vent the line to the top of the w/g and allow the wastegate to open.....good plan

or can my ms be set to power a relay (sensing through its map sensor)to switch air solenoid on?i think i may need to add extra circuitry to ms this way..

[Turbo-Brown]

You either need a spring that's at or lower than the boost pressure you want to run. That way, the ECU can block the signal to the gate to give more boost if required.

The solenoid will be normally open and connecting the WG to the pressurised side of the system. When the ECU wants to get more boost, it turn on the solenoid which closes off the pressure side and vents the gate to atmosphere.

This way, if the solenoid fails, you only get boost to the spring setting of the WG and not just as much boost as the turbo can make, which would be a lot in your case

[gcorky]

You either need a spring that's at or lower than the boost pressure you want to run. That way, the ECU can block the signal to the gate to give more boost if required.

The solenoid will be normally open and connecting the WG to the pressurised side of the system. When the ECU wants to get more boost, it turn on the solenoid which closes off the pressure side and vents the gate to atmosphere.

This way, if the solenoid fails, you only get boost to the spring setting of the WG and not just as much boost as the turbo can make, which would be a lot in your case

and in your case now ...lol...has it arrived, if so was the turbine housing an 18

[Ant]

instead plumb in an air pressure switch (to sense boost pressure)that in turn is controlling an air solenoid that merely opens up and vent the line to the top of the w/g and allow the wastegate to open.....good plan

or can my ms be set to power a relay (sensing through its map sensor)to switch air solenoid on?i think i may need to add extra circuitry to ms this way

MS can sense the boost , and using the 5 spare wires in your loom, all you need do is replicate the boost control circuit in the proto area off the -extra site, and decide which way around you'll use the new function

Yeah cmon Alex , spill the beans dude !, I trust the Holset was torn to shaft and core immediatly it arrived, mine and Fozzys sure were

[gcorky]

short term solution run the baby with a seperate air switch and solenoid...isolated from ms

wasted spark and fancy controlling later if i feel the urge

but i think Ant you are talking of control the line that opens the gate,i was meaning the opposite keep the top pressured until x psi .this way should stop boost creep etc ....does it make a lot off difference either way...

quicky again Ant,you sent ms to me with a map to get me running 85 percent out of the box....is the boost in relation to fuel/ignition following a table of some description or have you predetermined them up to the map sensor limit....just trying to understand a bit more?

cheers.

[Turbo-Brown]

just got an e-mail from the seller to say they've got the cheque and they'll be sending it off on Friday to arrive on Saturday, just in time for Christmas

Might even wrap it up for myself.

Think I'll leave it in one piece though, it's supposed to be brand new and it even looks as though the bearing section and turbine housing can be left where they are with just the compressor going round.....fingers crossed for an 18! Just gotta give the guy at the metal workers a prod for the delivery prices!

[gcorky]

when theyre new they dismantle in seconds specially with nice v-band housings,although the numbers on the turbine....

so your gonna substitute one of the smaller turbos Alex?

[Ant]

quicky again Ant,you sent ms to me with a map to get me running 85 percent out of the box....is the boost in relation to fuel/ignition following a table of some description or have you predetermined them up to the map sensor limit....just trying to understand a bit more?

I have lots of maps to suit mate, what target boost you aiming for ??

[gcorky]

hi Ant ,whats on mine-(can you remeber the map thats burned on it) think i may have mentioned 10 psi at the time...maybe youve done it to suit?

ive decided already im gonna go for more just as soon as its all leak free etc...

awaiting prices on an mls hg...someones quoted 400 quid for a spec 3 clutch....im going for a build thats capable first time hopefully,sick of throwing money down the drain.....i am sensible sometimes.

[Turbo-Brown]

so your gonna substitute one of the smaller turbos Alex?

Pretty much starting again from scratch, new manifolds and exhaust system, a more subtle intercooler, new and improved throttle bodies (or possibly a short runner intake depending on how much effort I can be arsed to put into the induction side of things this time)

Still got some decisions to make though like whether to go single or twin sequential though.

[gcorky]

so your gonna substitute one of the smaller turbos Alex?

Pretty much starting again from scratch, new manifolds and exhaust system, a more subtle intercooler, new and improved throttle bodies (or possibly a short runner intake depending on how much effort I can be arsed to put into the induction side of things this time)

Still got some decisions to make though like whether to go single or twin sequential though.

you had good results as is.....go twin sequential...be different

[e30_Turbo]

Think I'll leave it in one piece though, it's supposed to be brand new and it even looks as though the bearing section and turbine housing can be left where they are with just the compressor going round.

Alex,

Yours will be so easy to strip, mine was and it only needed heat up the hot end, was rather rusty tho.

Measure the wheels etc and we can work out the trim. Enjoy the V-band compressor system, some peeps aren't as lucky as us and have the other type that I've heard can break fingers trying to remove!!

Pics are also required

While we're chatting turbo's, I've sourced my next one, something tells me this isn't on a T3 flange tho

[mattG]

slight bonnet bulge

mark whats that off?