Just in general, when do you think it is wise to swap out to a bigger wastegate spring compared to just using a boost controller to increase boost?

Advantages/Disadvantages to running near/above 30psi on a 7psi spring as an example?

Advantages/Disadvantages to running near/above 30psi on a bigger spring such as a 14psi or 20psi spring.

How does it affect spool and boost control?

 

Adv - can run low boost for launches and lower gears
Disadv - 7psi spring probably won't hold 30+ psi

Adv - reliable boost control for 30psi+
Disadv - cannot run lower boost than the spring for launches and lower gears

Spool depends on how the controller is setup (can be setup to hold and ramp up steadily or light switch affect)
Boost control - see above responses

If you want both (low boost with small spring and high boost control at higher pressures), you should probably look into C02 for your BC and the wastegate outlets.

 

good luck getting to 30lbs on a 7psi spring. idk if you can even do that. i know i had a 7psi spring in my wastegate and it wouldnt hold past 14lbs with the duty cycle on my boost controller as high as it would go.(i use aem truboost)

 

I'm not doing that. I was just throwing that out as an example.


I was reading that running just a spring slows spool down and running with a boost controller actually help spool quicker. The more the spring is stressed, the quicker the spool because its not gonna crack the wastegate open. Thats kinda what got me curious. If that is the case, would it be beneficial then to run a spring that is around half of your target boost or would it be tough to consistently control boost that high?

As an example, Hallman claims that their ball-spring MBCs can increase spool by 600rpms.

 

I've gotten 39 psi on a 11 lb spring for what it's worth

I guess i should mention this is without CO2

 

Run the psi spring that you want for your low boost setup. I got a tial 7psi spring to hold to about 27psi with an AEM MAC solenoid. When I upgraded the spring the increase in spool was well worth it. You could also not hear the wastegate crack as soon with the stiffer spring.

You can only hold so much before back pressure opens a soft spring...Unless you use Co2 to close the wastegate like the drag cars your best to use a spring closest to the boost setting you plan to run.

 

TJ, it is my opinion that you pick the samllest pressure you want to run and put in the corresponding spring.

 

Why though? Whats the reasoning other than its the lowest you'll run in the car?

This question is just theory.

 

It's trial and error. Each setup and b.controller is different. Springs aren't cheap, so unless you have money to burn, make an educated guess.

I'm also the theory of running the smallest spring you can that won't hurt your overall psi.

Example 11psi making 30lbs. If you want to run 30lbs, and an 11psi spring will get you there, run it. No point in running a 14psi spring.

 

in my experience it seems that with a boost controller you can nicely control boost levels roughly 2X that of your spring rating. so i would use the 7psi for example for boost levels of around 14psi + or - a few psi but definitely not 30psi. at high boost levels the boost controller has a hard time keeping the target boost constant with an under rated spring.