I've gotten mixed answers everywhere I've asked, but for my target boost level of 14psi for a Greddy TT setup, what is the recommended wastegate spring I should get?

I have a Turboxs BCS installed btw and SVRT open dumps if that makes a difference....

---15psi spring and just keep the wg signal closed till 14psi is seen by MAP sensor?

---12psi spring + BCS?

Etc??

Any input greatly appreciated.....

 

I'm not sure what weights are available but I'd probably run a 10lb spring and run an electronic boost controller with it. General rule of thumb is that you don't want to go over double the psi of the wastegate spring. So, it'll give oyu some flexibility if you ever want to run more boost or leave it on wastegate spring and run like 9psi manifold pressure.

 

i would stay with the 10lb. springs and move up with the boost controller. either that or just up you target to 15psi and use the 15lb. springs.

 

They come in...

.5 bar / 7.25 psi
.6 bar / 8.70 psi
.7 bar / 10.15 psi
.8 bar / 11.60 psi
.9 bar / 13.05 psi
1.0 bar / 14.50 psi
1.1 bar / 15.95 psi

Answers I've gotten:

Get the 1.1 Bar and I'll see around 14, then use the BCS to keep the wg closed until target

Get the .5 Bar you'll have better control

Get the .8 Bar...

I would have thought the 1.0 or .9 Bar would be best? No?

 

My perception of which WG spring to run is a non issue with a boost control solenoid since the boost signal line will be holding the wastegate closed and not the spring pressure. When the desired boost is reached the solenoid will route the pressure to the opposite side of the diaphram opening the valve taking the spring pressure out of the equation. So you can run any spring you want and have the same results.

JET

 

1.0bar = 14.7 psi.

 

thats not entirely true JET, the boost signal goes to the spring side of the WG and the in port on the ebc. then you have an out line to the other side of the wg from the ebc. so what happens is the spring pressure is always there, but the ebc adds pressure to the opposite side to increase your possible boost level. so the spring pressure is always doing its job, the ebc just "pushes" on the other side of the WG, making the spring stronger, but not really. so if he gets a 14.7psi spring, hes still using the 14.7 spring, but the ebc makes it act like a 20psi spring by adding resistance to the other side.

i think thats right.

 

I believe the key is that an EBC can ADD pressure and assist a WG spring, but that it cannot reduce the force that the spring is making on it's own. This is what tig488 is referring to... I'm also under the impression that for "rock solid" boost, you want to try an get a spring that closest to your optimum setting. Low/Med/High boost settings are cool and all, but why bother? Get a spring that's suited to you goals and fine tune up to your desired boost levels.

Soooooooooo, I'd look at doing the following considering your goals:

.9 Bar Springs / EBC to 14psi

Just my

 

I run the Tial 1 bar WG springs for 13-13.5psi on WG spring. Boost builds quick about 10psi @ 3000rpms.

 

i ran the 5 pound stock springs on mine and boosted up to 22 psi a couple times. you can safely boost 15 psi more than the WG springs with no issues.


pretty much, anyone in the 350z market with external WGs doesnt need to worry about the springs...

 

Sounds good, 14 psi here I come... gotta match winston at least

 

Hey... where can I get springs for my WG greddy TT?

 

A one bar spring delivers 12.5psi-13psi in practice. IMHO, the less the boost controller has to work, the better your results will be. So if you are ok with 12.5psi as your lowest boost setting, I would swap to the 1 bar spring.

 

we have 1 bar springs in stock always...call if you need them.

 

Thanks!