wastegate question

[egmike]

If the stock setting of a intenal wastegate on turbo is 7 psi can it be set lower or it 7psi as low as it can go?

[HOK]

yup lowest... unless you put leaks into the system..

[legendboy]

if you leak the system you will boost more not less.

[2000impreza]

you can get a very weak bov and hope it leaks some boost. lol. there is not much you can do. maybe find a different wastegate...

[Illusionsir]

correct me if im wrong but are wastegates not spring driven??

If so, just take the spring out and you will have no boost. or reduce the spring coil which will make it lower.
(yes i know its internal)

just checking.

[legendboy]

can't change the spring in an internal wastegate.

[Illusionsir]

k cool, i just wasnt sure!

[legendboy]

if your feeling industrious you can customize your stock actuator arm so you can adjust it's length. thats how you can adjust your boost

[civic_rida]

When buyin a wastegate u should look at the lowest psi it can do and that should match up wit around what u wanna run right?

[2000impreza]

if you want to know about wastegates do some research.... anyways here is the basics of all basics on wastegate's. two different types:

internal-build into the turbo. you are stuck with what you have unless you can find a internal wastegate off another turbo that fits.

external-put on the exhaust charge pipe powering the turbo. you can get a softer spring.... but depends on the wastegate.

[egmike]

So If the internal wastegate was set at 7psi and you wanted to only boost 5psi think you could use a external wastegate as well to lower the boost ? or is that kinda pointless ?

[2000impreza]

you could disable your internal wastegate by not hooking up the vacuum tube.... and add a separate external wastegate. keep in mind with a external wastegate you should route it back to the exhaust after the turbo.... some guys run it open but its really loud.

[HOK]

Originally posted by legendboy
if you leak the system you will boost more not less.

i just got what you read.. no your right in a way.. the turbo will work harder but i meant leaking into the atmosphere.. if you have a leak in the compressor outlet your manifolds won't see boost... kinda meant as a joke anyways..

[Hollywood]

Originally posted by HOK


i just got what you read.. no your right in a way.. the turbo will work harder but i meant leaking into the atmosphere.. if you have a leak in the compressor outlet your manifolds won't see boost... kinda meant as a joke anyways..

He is right 100%.

Mike, I dought you will find a external wastegate that has a spring for 5psi, and if you could get one the external wastegate needs to be welded to your exhaust manifold, and the price of a external wastegate is around $500+.

Think about it this way though mike. If you think your car can run safe at 5 PSI but in danger zone at 7 PSI then maybe you should not do a turbo kit. That 2 PSI is not going to make that big of a difference if you run 7 and have a possibility of detination, then at 5 psi with small problems like low fuel in tank or hard cornering with low fuel or, bad gas, high heat...etc then you will get detonation there too. REM, Your engine/s will not be able to take the punishment of detonation like regular turbo'd cars.

I realize you are doing the boneyard turbo thing (trying to save money) but here is a small tip that does not cost a lot of $$$. Get a set of cold plugs number 7's, ex: PFR7B-9 This is a NGK Plat. cold plug for a SR20DET ;)

P.S. The nine is the gap.

[HOK]

actually with all this said tuning and fueling is key... you would be surprised how much boost you can run with proper tuning..

[egmike]

I won't install a turbo unless I have some kind of fuel management, The SOHC can 5psi with none, so if the wastegate is @ 7psi I will get a VAFC or something to manage that. I will be dropping in a newer engine D16Y8 with 80K on it as well, so i won't be boosting on my z6 that has 190K.

Although I wonder how long it would last.....:dunno:

[RT16V]

The lowest setting an internal wastgate will allow, is the boost level attained by running a boost source straight from the intake manifold (or the turbo's oputput) to the wategate actuator with out any control device (solenoid, bleed, ebc etc.) The best way to go lower, is to lengthen the actuator's arm, or make adjustable in length. Cut the arm (rod), then thread each piece. Install a small 'coupler' with lock nuts from the hardware store & you're set. Boost as low as you ever need to go.

[egmike]

So is safe to say that that how much the wastegate opens is dependant on how much boost?

so 7psi opens the wastegate less than 5 psi opens it ?

[legendboy]

No, if the wastegate spring is set at 7.5 psi then it will only actuate when the vacume line pressure reaches 7.5 psi.

[RT16V]

Originally posted by MR8
So is safe to say that that how much the wastegate opens is dependant on how much boost?

so 7psi opens the wastegate less than 5 psi opens it ?

No exactly, but really - if you can't set the boost low enough, build the adjustable arm. It's not very hard.

[legendboy]

wow, is there an echo in here? lol

[2000impreza]

i think what legendboy is saying is if your wastegate spring is rated to go off at 7psi then the wastegate won't open till 7 psi..... ajusting the wastegate rod won't do much. if you extend the length too much the wastegate flap won't close all the way.

[90_Shelby]

lIke it was said before lengthen the arm or take the arm right off the door and leave the valve fully open this would be the absolute lowest amount you could boost without enlarging the bypass hole.