Wastegate springs

[Bigsi15]

Hi guys, I'm completely stumped.

I've just fitted a kinugawa waste gate to my stock 1996 850 T5 as I've been having trouble with boost dropping. The waste gate has come with a variety of springs, 0.3, 0.5, 0.8, 1.2 bar but I have no idea which ones I'm supposed to be using for a stock car. I currently have 0.5 bar fitted which boosts fine to start with but will not go above about 0.4 bar according to my gauge

Are the springs the upper limit boost I.e a 0.5 bar spring will only allow up to 0.5 bar of boost or have I got it set up wrong? I had a feeling the old Volvo ones were set with about 4 psi of preload pressure which is about 0.3 bar however my new one is set with barely any pressure at all as I figured the weighting of the springs took care of that?

Please help!
Thanks

[Bigsi15]

Update...
It tried installing the 0.8 bar spring and things are only slightly better, now at the same point I was with the stock gate just reaching target boost occasionally then dropping back. Still no idea what spring I should be using or if I'm setting it up right


Thanks

[MoleT-5R]

Had a bit of a problem with an adjustable wastegate myself just recently, do be very careful in what you do with it, you don't want a tapping engine like mine from when I played with a 1bar spring and a boot load of throttle. Found this post on boost control that may help you understand the basics of springing etc..http://www.sr20-forum.com/information-library/16477-basics-boost-control-wastegates-how-turn-up-boost.html

tbh I'm going to drop down a couple of springs and start again gently from there and use my mbc gradually to achieve my target pressure....which is what I should have done first in all fairness......oh we live and learn lol.

[960kg]

It may help it may not!

This is quoted from Forge company that supply springs for actuators.

The spring rate is not the Boost rate?

Quote:

The following is general information regarding Forge actuator spring tensions and are important considerations when making a decision on which spring you install, especially if you are running a boost controller or planning an ECU upgrade.

The 4 springs we offer are listed below under their relevant colour codes and related pressures. Running pressure is the lowest or minimum pressure the spring will operate at, which is important when considering which spring you choose. The spool up pressure relates to the vacuum pressure required to lift the spring from its static position, at which point the turbo waste-gate will start to open (spool up).

The actual rating for these springs is as follows, the lower pressure being the spool up pressure and the higher pressure being the running pressure:

RED 17 psi (spool up) - 20 psi (running pressure) our product code FMAS049R.

BLUE 14 psi (spool up) - 18 psi (running pressure) our product code FMAS049B.

YELLOW 9 psi (spool up) - 15 psi (running pressure) our product code FMAS049Y.

GREEN 5 psi (spool up) - 10 psi (running pressure) our product code FMAS049G.

The spool up can be altered to a higher pressure by adding more tension to the spring. Be careful not to add too much tension to the spring as it will become coil bound, affecting the rod travel and thus affect the waste-gates ability to open effectively. Running pressure cannot be adjusted by adding pressure to the spring

[Bigsi15]

Thanks for your replies guys, mole sorry to hear it damaged your engine that sucks :( I'm hoping as mine has forged rods and won't boost higher than 0.5 bar anyway it will be ok! I'm now doing what your doing, starting from the lowest spring. I think part of the problem I'm seeing is the distance the wastegate arm travels per pressure. For example my stock gate only opens about 5mm at 0.2 bar then maybe 1.2 cm at 0.5 bar whereas the new one opens nearly a cm at 0.2 bar and further still at 0.5 according to my pump. They both start to open now at the same pressure. This would suggest that the reason my boost is low is that the bcs is maybe pushing on the gate as it would normally but causing the arm to move more than expected so lessening boost.

No idea how to resolve that unless the ecu eventually learns it...

[MoleT-5R]

Thanks for your replies guys, mole sorry to hear it damaged your engine that sucks :( I'm hoping as mine has forged rods and won't boost higher than 0.5 bar anyway it will be ok! I'm now doing what your doing, starting from the lowest spring. I think part of the problem I'm seeing is the distance the wastegate arm travels per pressure. For example my stock gate only opens about 5mm at 0.2 bar then maybe 1.2 cm at 0.5 bar whereas the new one opens nearly a cm at 0.2 bar and further still at 0.5 according to my pump. They both start to open now at the same pressure. This would suggest that the reason my boost is low is that the bcs is maybe pushing on the gate as it would normally but causing the arm to move more than expected so lessening boost.

No idea how to resolve that unless the ecu eventually learns it...

Forged rods will help a lot and practically insure against major troubles, A friend of mine recently had problems with a lack of boost and running the same actuator but with the 1.0/1.2 spring can't remember which, but had no boost, dropped back 2 springs and boost returned. As Keith mentioned about boost and spring rate, Kinuagwa's spring table shows full opening and dependant on pre-load the start point when the gate starts to creep open at a far lower pressure, the spring pressure stated is the full open pressure, which ticks me a bit as I was only running a 1 bar spring, mbc was wound off, but I think the error on my part was that I set the actuator as I would the standard one (i.e. the hole half way across the pin) hence the boost possibly came in way too fast for my engine......we live and learn....will be way more cautious in future

[Bigsi15]

:( they are funny beings sometimes these engines aren't they. Ok interesting to note full opening pressures. TBH I tried exactly what you did too on the lowest 0.3 bar spring by preloading it with 4psi as I did the old gate and it moved so far I couldn't screw the hole back enough to meet the arm in the closed position! This suggests it needs to be set with no prelod at all at the beginning and rely on the spring tension to achieve target boost. Probably also help to have a Mbc. Agreed with the spring pressure is full open as my 0.3 bar spring used in that example gave me just over 0.2 bar boost according to my gauge.

I have given up for now, my car is stock so won't make much change and it is probably best to use the gate when it is tuned to make sure all is safe and well

[Bigsi15]

Love that yellow t5r in your signature too buddy :)

[M-R-P]

The spring rate should be roughly half the max boost psi.

I'd get aperture tester on it and adjust it until the actuator starts moving the rod at around 5psi.

[PNuT]

sounds like the recuirculation valve if you have no audible boost leaks

[960kg]

Just found this in my photos of the way i set up my basic boost.....may be handy?

The sphyg pressure shown may not be correct just for displaying?

Sphyg was around £7 on eBay then...