Same PSI, different WG spring= different HP?
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Joined: Nov 2018
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Same PSI, different WG spring= different HP? Same turbo and all, I just changed the waste gate spring from the 5.5lb one that came in it to the 6.5 middle weight one. The same position on the boost controller gave me about 8 psi with the 6.5 where the 5.5 gave me 10. I messed with it another full turn maybe and got back to the 10-11 psi mark. It may just be me but it feels like it produces power different? I dont know about less, kind of feels like less according to the seat of my pants and the tires feel like they bark a little less in the shift.
This is my first non factory turbo so first external waste gate to mess with. Is this a thing or am i just imagining it? I would think the boost would come in faster and stronger with a stiffer spring. AFR's were all groovy.
This is my first non factory turbo so first external waste gate to mess with. Is this a thing or am i just imagining it? I would think the boost would come in faster and stronger with a stiffer spring. AFR's were all groovy.
Thread Starter
TECH Regular
Joined: Nov 2018
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I just went from a 5.5 to a 6.5 for a couple more psi. The boost just came in at a slightly different time after changing it. Being a manual controller under the hood it just took me a bit to dial it back in to the right setting.
You should always verify gate opening pressure with a compressor and a simple 15-30psi pressure gauge. If the spring was stiffer then it would hold the gate closed longer and almost flutter open and closed. Which can make the power feel sluggy vs smooth with a lower psi spring which tent to open and close smoother and less snapping open closed.
If if you have a MBC you should run the lightest spring that your MBC or EBC will net you the correct boost you want. Remember that opening pressure with a compressor is not the same as on the motor as you will be fighting exhaust pressure which will push it open sooner as well as force applied depending on the valve size as the force is proportional to valve size that the exhaust pushed back on. A 12psi spring in a 60mm WG shows 12psi cracking pressure on the compressor but in the car it netted 8psi. I can push the boost to 15psi on an EBC at 70% DC. On a 5.5psi spring you should. Net at least 11psi or more.
If if you have a MBC you should run the lightest spring that your MBC or EBC will net you the correct boost you want. Remember that opening pressure with a compressor is not the same as on the motor as you will be fighting exhaust pressure which will push it open sooner as well as force applied depending on the valve size as the force is proportional to valve size that the exhaust pushed back on. A 12psi spring in a 60mm WG shows 12psi cracking pressure on the compressor but in the car it netted 8psi. I can push the boost to 15psi on an EBC at 70% DC. On a 5.5psi spring you should. Net at least 11psi or more.
