Wastegate Springs
Thread Starter
Joined: Oct 2016
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From: Armstrong BC
Wastegate Springs Hey guys quick question so I got a new 50mm Turbosmart gen 5 gate it says the 14 psi spring is installed but turns out the 7 and 5 psi springs are in there for 12 psi. Would it be better to run a slightly less spring and use more controller than a heavier spring with less controller?? Everything is controlled by the Dominator ecu and target boost is 25 psi for now. Turbo is a TNT 88/96 T6 with the gate inline before the flange. I'm also not running Co2 or on board air it's just plumbed from the compressor into the bottom port and into the mac valves. Thanks guys.
How are you going to make 25 psi without C02?
I'm running 2 46mm WGs, single midframe 85, and am running 3 lb springs. But when I next have the engine out I'd probably switch to 6-8 lb springs though I don't need to.
I'm running 2 46mm WGs, single midframe 85, and am running 3 lb springs. But when I next have the engine out I'd probably switch to 6-8 lb springs though I don't need to.
Thread Starter
Joined: Oct 2016
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From: Armstrong BC
Last edited by 91 Z28; Jan 25, 2026 at 04:53 PM.
Nice, I had my combo make 18 psi in 1.2 seconds, 8 on the leave, but I have to use C02. Without a wg reference it would make about 14 psi at 7100 in 1st gear.
Sorry if I'm taking your thread on a tangent.
Sorry if I'm taking your thread on a tangent.
Thread Starter
Joined: Oct 2016
Posts: 1,584
Likes: 374
From: Armstrong BC
No worries. I've never actually given this any kind of thought so I'm curious to know what everyone's thoughts are on this. I've been considering getting a Motion Raceworks CO2 setup since I've got no back seats I'd just mount the bottle beside the fire extinguisher
Depends on how much BP you're seeing in the hotside.
I tried 3-4lb. springs in my last car which was a single 44mm on an LS1 with a 7875 and the BP would push the gate open prematurely. I stepped up to a 6-7 lb. spring and got my control back.
I run 6-7 lb. springs now and made almost 16 lbs. using reference pressure and then 22 using compressed air.
For a streetcar I'd do compressed air before I did CO2.
I tried 3-4lb. springs in my last car which was a single 44mm on an LS1 with a 7875 and the BP would push the gate open prematurely. I stepped up to a 6-7 lb. spring and got my control back.
I run 6-7 lb. springs now and made almost 16 lbs. using reference pressure and then 22 using compressed air.
For a streetcar I'd do compressed air before I did CO2.
Thread Starter
Joined: Oct 2016
Posts: 1,584
Likes: 374
From: Armstrong BC
Depends on how much BP you're seeing in the hotside.
I tried 3-4lb. springs in my last car which was a single 44mm on an LS1 with a 7875 and the BP would push the gate open prematurely. I stepped up to a 6-7 lb. spring and got my control back.
I run 6-7 lb. springs now and made almost 16 lbs. using reference pressure and then 22 using compressed air.
For a streetcar I'd do compressed air before I did CO2.
I tried 3-4lb. springs in my last car which was a single 44mm on an LS1 with a 7875 and the BP would push the gate open prematurely. I stepped up to a 6-7 lb. spring and got my control back.
I run 6-7 lb. springs now and made almost 16 lbs. using reference pressure and then 22 using compressed air.
For a streetcar I'd do compressed air before I did CO2.
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Verdad Gallardo This is the one I use, works great. Fills the tank in about 1-2 minutes and is pretty quiet. If you can make sure your system is leak free it'll hold pressure much longer. It never really bothers me, so I haven't put any effort into finding all the little leaks.
Thread Starter
Joined: Oct 2016
Posts: 1,584
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From: Armstrong BC
This is the one I use, works great. Fills the tank in about 1-2 minutes and is pretty quiet. If you can make sure your system is leak free it'll hold pressure much longer. It never really bothers me, so I haven't put any effort into finding all the little leaks.
My whole thing is if you forget to turn it off and it leaks out, then the next time you go to drive you're out whatever the CO2 powers.
Plus, with CA you can air down your tires at the track and fill them back up.
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It ultimately depends on how much resolution you want/need out of your setup. Are you traction limited as it is now? If so, you don't want to put more wastegate spring in because that will make it worse. If not, and you can get away with more boost before traction becomes an issue, then you can add in some wastegate spring.
I like to keep just enough spring in the gate to where you can have fun on the street without getting dangerous, on the wastegate setting. Then use the ECU to add boost from there. Having a rotary switch definitely helps in that regard because you can change your boost on the fly (as long as it's configured).
I also run the Viair system. Its pretty convenient and you don't ever have to worry about running out. And then, like mentioned above, you can plumb in an air hose to top off your tires if needed. Some people will use it to blow out their rear mounted radiator setups because they can accumulate debris. I run AN lines on mine and don't have any leaks.
I like to keep just enough spring in the gate to where you can have fun on the street without getting dangerous, on the wastegate setting. Then use the ECU to add boost from there. Having a rotary switch definitely helps in that regard because you can change your boost on the fly (as long as it's configured).
I also run the Viair system. Its pretty convenient and you don't ever have to worry about running out. And then, like mentioned above, you can plumb in an air hose to top off your tires if needed. Some people will use it to blow out their rear mounted radiator setups because they can accumulate debris. I run AN lines on mine and don't have any leaks.