1. The Turbo Forums - The discussion board for both hard core and beginner turbocharged vehicle enthusiasts. Covering everything from stock turbocharger cars, seriously fast drag racers, boats, motorcycles, and daily driver modified turbo cars and trucks.
    To start posting in our forums, and comment on articles and blogs please

    IF YOU ARE AN EXISTING MEMBER: You can retrieve your a password for your account here: click here.

need heavier WG springs?

Discussion in 'Newbie and Basic Turbo Tech Forum' started by ChevelleFan, Jul 1, 2024.

  1. ChevelleFan

    Aug 31, 2016
    I have 2 50mm wastegates on my SBC single-turbo setup, one per bank.

    I ended up buying them at different times (i didnt know I needed 2) so, this is what I have:


    Where do I get heavier springs for these? The guys at the counter at Summit yesterday came up empty.

    Both come with a 4 & 6 lb spring, and both WGs have both springs installed. And I have an AmpEFI electronic boost controller too. Yet, I'm only able to get about 8-8.5 psi of boost at 100% DC on the boost controller.

    How do I get up to 14psi?
  2. B E N

    Nov 22, 2016
    You can use a combination of the included three springs to up your rate, there will be 3 different steps that the springs register on inside the gate.
  3. ChevelleFan

    Aug 31, 2016
    The pic shows 3 springs, but there is only 2 in reality. I'll open them both up again and take a look, but I'm 99% there is only 2.

    What surprises me is that I thought there would be a some sort of commonly available assortment of springs, and that doesn't seem to be the case.
  4. B E N

    Nov 22, 2016
    You might be able to use ones from someone like precision, but you would have to do measurements to see. I'm not sure what gates summit cloned for those
  5. Wallace

    Dec 3, 2004
    How do you have the boost controller connected? Have you inspected the gates to be sure they aren't binding? Fire rings installed?
    ummduh likes this.
  6. Russell

    Jan 13, 2019
    Check for boost and exhaust leaks, I swore I didn't have any boost leaks, until I capped the turbo and pressurized the intake track. Even found where I left the O-ring off the blow off valve.

    What engine (and mods). What size turbo?
    ummduh likes this.
  7. ChevelleFan

    Aug 31, 2016
    All the turbo stuff is pretty new -- I have less than 10 dragstrip passes and probably less than 100 street miles.
    Engine is 400ci SBC, 80mm BW Turbo, (2) 50mm wastegates, (1) 60mm BOV. Engine was purpose built for boost in '21 and might have 1500-2000 miles on it.

    Boost controller is hooked to switched +12v power and the other wire to BOOST output on my MS3X. The blue lines go to the tops of the WGs, the reds to the bottom of the WG. The line on the 90* on the red side goes to the intake plenum. It seems to work as expected, as when no boost control was called for, it would peak up to 7psi and taper down to 4psi on a pass.

    20240128_232038.jpg #ad

    20240128_232504.jpg #ad

    Datalog-10.42@128.png #ad

    May 25, 2004
    It looks to me that it's still using spring pressure. In TS I think I found a setting that allows the duty cycle to be reversed. In other words if you lower the DC this may increase boost not lower it.

    ummduh and B E N like this.
  9. ummduh

    Nov 19, 2016
    Iirc I read somewhere that the vsr wastegates use tial springs and diaphragm. I havent tested this.

    But I'm running a single vsr with a 3 port Mac, have the 6lb spring in it and can hit 18psi @75% DC.

    Initially I had a difficult time getting it to work, I found all my gate air fittings were loose.

    Edit: the blue line to the intake plenum should be before the throttle body, pretty sure, I run mine direct from the turbo outlet.
  10. Russell

    Jan 13, 2019
    Did you take the WG apart and inspect the inside. I have had the set screws come out. The diaphragm pinched.

    Have you tested the gate with compressed air? I have a 0-30psi regulator that I hook to the bottom and can watch the gate crank, and go to full open.

    Sounds like you Mac values are not applying pressure to the top of the gate. Put shop air on the Mac value and adjust the duty cycle and see where it starts flowing. I have never tried it but I don't see why you could hook the gate up on the bench the same way with shop air and go through a range of duty cycles it will not be exact because it doesn't have exhaust pressure pushing on the valve. But I would think it should open and close.
  11. Forcefed86

    Nov 24, 2005
    You need to back off and start from scratch IMO. I see a couple things…

    Why are you using 100mm worth of gate on a single turbo setup? That’s nuts. It will make controlling the boost more difficult than it needs to be. A tiny crack of each valve/gate will let out a ton of exhaust pressure, making control difficult.

    Are you running a divided setup? 38mm gates are MORE Than enough. If not… you don’t need 2 gates. Where are the WG’s located on the hot side?

    I’d pull one gate and test it with shop air.


    With and 6lb and a 4lb spring the gate should crack at 10psi form the shop air with just the bottom port connected. Make sure it’s doing this. If not you don’t have 10psi worth of spring installed. Also check for leaks at that time. Once you have confirmed this with no leaks you can install it.

    Though at this point I'd install the lines/MAC valve and not the gate itself. Then use shop air on the supply and use the MS3 test feature to pulse the mac valve at different duty cycles. You can then watch the gate valve move to ensure you have the polarity and HZ correct.
  12. ChevelleFan

    Aug 31, 2016
  13. Forcefed86

    Nov 24, 2005
    It’s best to have 2 in that case. Just wouldn’t have suggested 50’s. Not saying 50’s wont’ work. They will just be “touchy”. When the cracking pressure is reached, a lot of exhaust pressure will escape very quickly. So manifold pressure will want to oscillate there. Boost control will undershoot and overshoot and you’ll have to spend some time dialing in the PID settings for closed loop BC.

    You should be good with 10lb springs. I get 9lbs with my “10lb springs” w 2 38mm gates. Can adjust up to 30+ if I want with a simple 3-port mac. Thats on a S480 single on a divided hotside LS SBC setup.

    You want it plumbed in a way that all the boost is diverted to the bottom port only if the BC is off. And at 100% DC all the boost is directed to the top port and none to the bottom.
  14. ChevelleFan

    Aug 31, 2016
    Pulled the WGs off tonight and opened them up... the short version is I think I need to buy a matching WG. But which one?

    Driver's side WG is a VS Racing with 6 screws holding the spring housing. It's a diaphragm style and had 2 springs. They much larger physically than the Summt springs.

    Passenger side WG is a Summit Racing with something akin to a v-band clamp holding the spring housing on. It was a piston style WG. It also had 2 springs, physically smaller than the VS springs. This one seemed much easier to service in terms of opening it up.

    We took measurements of all 4 springs for height, diameter, and thickness of wire.

    Very unscientifically, my friend and I both felt the VS Racing unit was stiffer as we pushed open the WG with our fingers.

    Ok, that makes sense to me, but does that mean the documentation is wrong? My setup is shown in post #7, which is similar to the documentation, here: https://www.ampefi.com/product/ebc-electronic-boost-control-solenoid-kit/

    Because in their plumbing diagram for a 2-port, how is there ever NOT going to be boost to the bottom port? (their pics are lousy)


    Last edited: Jul 11, 2024
  15. ChevelleFan

    Aug 31, 2016
    Before the throttle body?? I'm taking it from the plenum, and it's on the red side (bottom port).. I don't have an outlet on my compressor housing.
  16. underpsi68

    Jul 9, 2005
    I have my mac valve plumbed like diagram 2 in the above. With 4.5 wg springs I can make 30+lbs.
  17. B E N

    Nov 22, 2016
    Boost doesn't care if the gates match or not. Shim the springs you have or add another spring to the gate.
  18. Russell

    Jan 13, 2019
    I thought you had to have a 4 port to have 100% going to the top only. That's what I am using.

    I drilled an tapped a hole in the cover on my turbo to feed the Mac value. The farther away from the turbo the more loses you will have so that why I assume you want as close to the turbo as possible to get you boost from not using CO2 or on board air.
    ChevelleFan likes this.
  19. Forcefed86

    Nov 24, 2005
    You can get the same minimum and maximum boost with a 3 port plumbed like this. You just have a bit more resolution with a 4 port. Def. don't "need" a 4 port.

    upload_2024-7-14_12-35-12.png #ad
    B E N and Russell like this.
  20. Russell

    Jan 13, 2019
    I didn't know that was an option.
Similar Topics - heavier springs Forum Date
Wastegate springs Newbie and Basic Turbo Tech Forum Jul 31, 2020
New guy and question on wastegate springs- Ford 200 I6 Newbie and Basic Turbo Tech Forum Jul 4, 2020
18 pound springs only 12 pound boost Newbie and Basic Turbo Tech Forum Mar 30, 2014