How to know Wastegate spring pressure??
03-01-05, 02:50 AM
#1
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How to know Wastegate spring pressure??
ok, i have a blitz type B wastegate.. i have been looking at pics of blitz wastegates to confirm its a blitz becuase i looked at my firends and his was different. i now know they make 2 different ones. now, the previous owner didnt know what the psi setting for the spring is thats in there is so i want to know if my idea will work?
if i take a boost pressure tester (a hand pump that makes boost) and it has a psi gauge on it and put a vacuume line on the wastegate, will it open up when it reaches the set psi??? or will it need to be on the car before something happens??
the reason why i ask is if the spring is set for lets say, 15 lbs, i want to know now and change it to a lower one so i can run lets say 11 or 12 lbs....
Thanks a lot and i appreciate all the help!!
-Roman
if i take a boost pressure tester (a hand pump that makes boost) and it has a psi gauge on it and put a vacuume line on the wastegate, will it open up when it reaches the set psi??? or will it need to be on the car before something happens??
the reason why i ask is if the spring is set for lets say, 15 lbs, i want to know now and change it to a lower one so i can run lets say 11 or 12 lbs....
Thanks a lot and i appreciate all the help!!
-Roman
03-01-05, 04:00 AM
#2
John
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hook up just the side port to the intake manifold. Whatever you boost to is what the pressure of the spring is. Though it doesn't always turn out that way, most ofthe time it is accurate.
03-01-05, 11:11 AM
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Originally Posted by 2a+RoN
it should not matter if it is on the car or not, as long as it sees the pressure it is set for, it should open.
if u have a 1bar spring u cant use a Bc to make it boost at 12
cant lower the boost w/BC if the WG spring is set for a higher target boost setting
i know some fools that dont even have a BC and rely on the WG for boost management
stupid but they say its effective
correct me if im worng people
mike
03-01-05, 05:00 PM
#5
No it's not Turbo'd
You're right, get it checked, by someone that can pressureize a hose and see when it opens.... if it's a 1 Bar spring, you'll know on the stock computer right about when your seals blow @ 12-14 psi 
On an aftermarket.... as soon as you have too little fuel for when it finally opens.
Another idea is to possibly buy a spring that you want, say 7-10 psi, compare it, if it's the same, return the new one, if it's different, install the new one
On an aftermarket.... as soon as you have too little fuel for when it finally opens.
Another idea is to possibly buy a spring that you want, say 7-10 psi, compare it, if it's the same, return the new one, if it's different, install the new one
03-01-05, 05:59 PM
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Originally Posted by DCrosby
You're right, get it checked, by someone that can pressureize a hose and see when it opens.... if it's a 1 Bar spring, you'll know on the stock computer right about when your seals blow @ 12-14 psi
On an aftermarket.... as soon as you have too little fuel for when it finally opens.
Another idea is to possibly buy a spring that you want, say 7-10 psi, compare it, if it's the same, return the new one, if it's different, install the new one
On an aftermarket.... as soon as you have too little fuel for when it finally opens.
Another idea is to possibly buy a spring that you want, say 7-10 psi, compare it, if it's the same, return the new one, if it's different, install the new one
hahaha..... why so hostile! j/k
ahaha.. im with you but the problem is that it will take 2-4 months from Blitzusa... and i dont know if any other ones are interchangeable... so im stuck with what i got for the time being... so, will it work or were you being sarcastic?
Thx
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03-01-05, 06:29 PM
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Originally Posted by 2a+RoN
it should not matter if it is on the car or not, as long as it sees the pressure it is set for, it should open.
so i can pump boost in there and the spring should start opening... ??? im going to try itt today and let you guy's know..
03-01-05, 11:39 PM
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ok, so i tired it with a hand pump and got nothin below 20lbs... then i tired an air compressor and it worked so i t-ed a boost (only boost, no vaccume) guage to it and it started opening at 22-23psi!!! i highly doubt that it is a 23lb spring.. so we were confused.. then, my firend gave me the idea about atmosphereic pressure... basicly, anything that the guage shows under 14.7 lbs is vacuume and the rest is boost?? this would make sense becasue the stock mazda boost guage is a 2 bar (29.4lb) sensor but doesnt read anything above 14.7 lbs.. the first is just vacuume... is anyone good at this or knows more about it than me would help me out??? im lost!!!
if what i descovered is true, then i have a 9 or 10 lb spring... which would make sense!!
AAAAAAAAAAAAAAAAAAAAAAAHHHHHH !!!!!!!!!!!!! im going crazy!!! anyone ???? help me out!!
if what i descovered is true, then i have a 9 or 10 lb spring... which would make sense!!
AAAAAAAAAAAAAAAAAAAAAAAHHHHHH !!!!!!!!!!!!! im going crazy!!! anyone ???? help me out!!
03-02-05, 07:30 AM
#11
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i am not familiar w your specific wastegate. if it works in the common fashion, it has a line in that communicates w the pressure from your turbo compressor housing or intake manifold runners thru a boost controller solenoid /or not/ thru a BC if you don't run one...
the executive summary: if you were able to pump the wastegate actuator up to 20 psi and the spring didn't move (opening the valve) your spring is way too stiff.
many people haven't thought out how springs work:
a ten pound linear rate spring for example.
10 pounds of force will move the spring 1 inch.
5 pounds force will move it one half inch. ( that's why a 10 pound spring will start to open at less than ten pounds.)
20 pounds will depress a 10 pound spring two inches
i don't know how Blitz/Greddy/HKS rate their wastegate springs. is a true 10 pound per inch spring considered a "10 pound spring," or is it a spring that is sufficiently stiff as to allow the average motor to make 10 psi intake pressure?
i will tell you that i recently checked a few wastegate actuators. i found that they started to open at 9 psi on my the pressure gauge on my Mitey Vac. my guess is that's about what you are looking for as you can run a controlled 9 to 20 something psi with such a spring and a good boost controller.
there is another powerful factor effecting wastegate dynamics.
exhaust pressure:
just like there is pressure from the compressor in the intake runners of you motor, say 10 psi... there is pressure out the exhaust side of the motor. primarily from the exhaust port to the turbo turbine. it is this pressure that drives the turbo. depending (primarily) on the sizing of your turbine housing and turbine wheel the exhaust pressure may be between 1 and 2X of your intake pressure.
you could easily be making 10 psi at your intake and 20 psi out the exhaust port. for this reason, if your feel your wastegate open and you look at your boost gauge and see you are making 10 psi it does not mean you have a 10 pound spring. (of course you could consider it to be a 10 pound spring if you wished to think pragmatically.)
my advice is that if your spring didn't move at 10 psi pressure on the gauge call a good turbo shop and ask them for advice as to a spring rate for you. you will probably end up w something in the 9/10 range... which BTW, is what is on the OEM fd.
good luck,
howard coleman
the executive summary: if you were able to pump the wastegate actuator up to 20 psi and the spring didn't move (opening the valve) your spring is way too stiff.
many people haven't thought out how springs work:
a ten pound linear rate spring for example.
10 pounds of force will move the spring 1 inch.
5 pounds force will move it one half inch. ( that's why a 10 pound spring will start to open at less than ten pounds.)
20 pounds will depress a 10 pound spring two inches
i don't know how Blitz/Greddy/HKS rate their wastegate springs. is a true 10 pound per inch spring considered a "10 pound spring," or is it a spring that is sufficiently stiff as to allow the average motor to make 10 psi intake pressure?
i will tell you that i recently checked a few wastegate actuators. i found that they started to open at 9 psi on my the pressure gauge on my Mitey Vac. my guess is that's about what you are looking for as you can run a controlled 9 to 20 something psi with such a spring and a good boost controller.
there is another powerful factor effecting wastegate dynamics.
exhaust pressure:
just like there is pressure from the compressor in the intake runners of you motor, say 10 psi... there is pressure out the exhaust side of the motor. primarily from the exhaust port to the turbo turbine. it is this pressure that drives the turbo. depending (primarily) on the sizing of your turbine housing and turbine wheel the exhaust pressure may be between 1 and 2X of your intake pressure.
you could easily be making 10 psi at your intake and 20 psi out the exhaust port. for this reason, if your feel your wastegate open and you look at your boost gauge and see you are making 10 psi it does not mean you have a 10 pound spring. (of course you could consider it to be a 10 pound spring if you wished to think pragmatically.)
my advice is that if your spring didn't move at 10 psi pressure on the gauge call a good turbo shop and ask them for advice as to a spring rate for you. you will probably end up w something in the 9/10 range... which BTW, is what is on the OEM fd.
good luck,
howard coleman
12-09-15, 09:42 PM
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i am not familiar w your specific wastegate. if it works in the common fashion, it has a line in that communicates w the pressure from your turbo compressor housing or intake manifold runners thru a boost controller solenoid /or not/ thru a BC if you don't run one...
the executive summary: if you were able to pump the wastegate actuator up to 20 psi and the spring didn't move (opening the valve) your spring is way too stiff.
many people haven't thought out how springs work:
a ten pound linear rate spring for example.
10 pounds of force will move the spring 1 inch.
5 pounds force will move it one half inch. ( that's why a 10 pound spring will start to open at less than ten pounds.)
20 pounds will depress a 10 pound spring two inches
i don't know how Blitz/Greddy/HKS rate their wastegate springs. is a true 10 pound per inch spring considered a "10 pound spring," or is it a spring that is sufficiently stiff as to allow the average motor to make 10 psi intake pressure?
i will tell you that i recently checked a few wastegate actuators. i found that they started to open at 9 psi on my the pressure gauge on my Mitey Vac. my guess is that's about what you are looking for as you can run a controlled 9 to 20 something psi with such a spring and a good boost controller.
there is another powerful factor effecting wastegate dynamics.
exhaust pressure:
just like there is pressure from the compressor in the intake runners of you motor, say 10 psi... there is pressure out the exhaust side of the motor. primarily from the exhaust port to the turbo turbine. it is this pressure that drives the turbo. depending (primarily) on the sizing of your turbine housing and turbine wheel the exhaust pressure may be between 1 and 2X of your intake pressure.
you could easily be making 10 psi at your intake and 20 psi out the exhaust port. for this reason, if your feel your wastegate open and you look at your boost gauge and see you are making 10 psi it does not mean you have a 10 pound spring. (of course you could consider it to be a 10 pound spring if you wished to think pragmatically.)
my advice is that if your spring didn't move at 10 psi pressure on the gauge call a good turbo shop and ask them for advice as to a spring rate for you. you will probably end up w something in the 9/10 range... which BTW, is what is on the OEM fd.
good luck,
howard coleman
the executive summary: if you were able to pump the wastegate actuator up to 20 psi and the spring didn't move (opening the valve) your spring is way too stiff.
many people haven't thought out how springs work:
a ten pound linear rate spring for example.
10 pounds of force will move the spring 1 inch.
5 pounds force will move it one half inch. ( that's why a 10 pound spring will start to open at less than ten pounds.)
20 pounds will depress a 10 pound spring two inches
i don't know how Blitz/Greddy/HKS rate their wastegate springs. is a true 10 pound per inch spring considered a "10 pound spring," or is it a spring that is sufficiently stiff as to allow the average motor to make 10 psi intake pressure?
i will tell you that i recently checked a few wastegate actuators. i found that they started to open at 9 psi on my the pressure gauge on my Mitey Vac. my guess is that's about what you are looking for as you can run a controlled 9 to 20 something psi with such a spring and a good boost controller.
there is another powerful factor effecting wastegate dynamics.
exhaust pressure:
just like there is pressure from the compressor in the intake runners of you motor, say 10 psi... there is pressure out the exhaust side of the motor. primarily from the exhaust port to the turbo turbine. it is this pressure that drives the turbo. depending (primarily) on the sizing of your turbine housing and turbine wheel the exhaust pressure may be between 1 and 2X of your intake pressure.
you could easily be making 10 psi at your intake and 20 psi out the exhaust port. for this reason, if your feel your wastegate open and you look at your boost gauge and see you are making 10 psi it does not mean you have a 10 pound spring. (of course you could consider it to be a 10 pound spring if you wished to think pragmatically.)
my advice is that if your spring didn't move at 10 psi pressure on the gauge call a good turbo shop and ask them for advice as to a spring rate for you. you will probably end up w something in the 9/10 range... which BTW, is what is on the OEM fd.
good luck,
howard coleman
This is a very interesting topic to me!
I have a bunch of questions about this,
1. If my target boost max was 20psi, and I anticipate buying a 10psi spring and turning it up, how much exhaust gas pressure would it take to start interfering with my intake manifold pressure? Is there an anticipatory ratio of drive pressure like 2:1 I should be concerned about? Do we normally worry about such things, or is it better to just buy and try, then adjust later.
2. Would a good electronic boost controller be able to remove alot of that issue?
3. Does an early opening gate due to high EGP contribute to lower intake manifold pressures, or only slower boost rising rates, or both? i.e. if I buy a 15psi gate spring, and my combo has a LOT of EGP, will it deny me a full 15psi of intake manifold pressure? If so, how much lower could it become?
4. Doesn't a larger diaphragm allow for a larger spring to be used, and thus larger springs/diaphragm combos (although slower) able to resist more Exhaust gas pressure? Is there any company that offers a special "robust diaphragm/spring" combo for this situation?
5. Lets say I buy a 15psi gate but it comes on very very slow due to an early crack because of high EGP. If I buy a stiffer spring, isn't that the same as raising the boost pressure? In other words, if I ever have an EGP problem, buying a stiffer spring will just increase the boost pressure on me- it isn't really a good solution because now I am over boosting (compared to before). How can I buy a stiffer spring without getting more max boost?
Last, do you feel that in your opinion this issue (exhaust gas pressure vs wastegates) is worth considering in a novice (first timer turbo) application? What can a novice do to assure that the spring/gate design will be sufficient for their application? (How can knowledge of this issue save us time or money)?
Thanks!!!!
Last edited by Kingtal0n; 12-09-15 at 09:44 PM.
12-11-15, 11:02 AM
#13
You guys are all forgetting Manifold Pressure.
If you have a 10 pound spring, 10 pounds of air pressure through the bottom port will not be enough on its own to open the wastegate. If you are only using air pressure you will need roughly double the air pressure to crack the gate open.
So if you need 20-23 lbs to open that gate with just air your wastegate spring is roughly 10-12psi.
If you have a 10 pound spring, 10 pounds of air pressure through the bottom port will not be enough on its own to open the wastegate. If you are only using air pressure you will need roughly double the air pressure to crack the gate open.
So if you need 20-23 lbs to open that gate with just air your wastegate spring is roughly 10-12psi.
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