Adjustable Pressure Relief Valve!
08-16-2008, 02:21 PM
#1
Adjustable Pressure Relief Valve!
Hey everyone!
This is one of my ideas that has recently come to life and will soon be on my v-mount supercharged 350z thanks to 928 Motorsports! The adjustable pressure relief valve! Everyone has heard of people rigging up wastegates to bleed off boost pressure on their supercharged Z's so they can get more mid-range but not exceed the limits of their stock blocks.
A while back, when I finished making the supercharger kit for my car I decided that this was something I wanted to do but I didn't want to spend the amount of money that some of the other people had spent on doing this. This stemed the idea for a billet relief valve with some adjustability it in! From there 928 Motorsports stepped in to bring this idea to life and this is the result(Picture is of it on our Porsche 928):
Using a 1" NPT weld on bung this unit will thread into the bung on one of the intake pipes on my Z and I should hopefully be able to put a 3" pulley on my car and get some really good numbers!!! I currently have a 3.25" pulley and hit about 9psi on my car with my setup. This unit vents out of 6 half inch holes and uses a teflon ball for sealing. It is adjustable from 8-31psi with the current spring setup I have in it.
Let me know what you guys think about it!
My Setup:
This is one of my ideas that has recently come to life and will soon be on my v-mount supercharged 350z thanks to 928 Motorsports! The adjustable pressure relief valve! Everyone has heard of people rigging up wastegates to bleed off boost pressure on their supercharged Z's so they can get more mid-range but not exceed the limits of their stock blocks.
A while back, when I finished making the supercharger kit for my car I decided that this was something I wanted to do but I didn't want to spend the amount of money that some of the other people had spent on doing this. This stemed the idea for a billet relief valve with some adjustability it in! From there 928 Motorsports stepped in to bring this idea to life and this is the result(Picture is of it on our Porsche 928):
Using a 1" NPT weld on bung this unit will thread into the bung on one of the intake pipes on my Z and I should hopefully be able to put a 3" pulley on my car and get some really good numbers!!! I currently have a 3.25" pulley and hit about 9psi on my car with my setup. This unit vents out of 6 half inch holes and uses a teflon ball for sealing. It is adjustable from 8-31psi with the current spring setup I have in it.
Let me know what you guys think about it!
My Setup:
Last edited by Quamen; 08-17-2008 at 06:04 PM.
08-16-2008, 02:45 PM
#3
That is a great idea, and something I would DEFINITELY do if I had a supercharged car. Just make sure you don't over spin the blower, that is the only negative thing I can think of from this mod, but you probably already took that into consideration I am sure 
You should have a much better power curve now. DYNO! 
-George
You should have a much better power curve now. DYNO! -George
08-16-2008, 03:04 PM
#4
Originally Posted by George@GTM
That is a great idea, and something I would DEFINITELY do if I had a supercharged car. Just make sure you don't over spin the blower, that is the only negative thing I can think of from this mod, but you probably already took that into consideration I am sure You should have a much better power curve now. DYNO!
-George
You should have a much better power curve now. DYNO! -George
Trust me... there will be dynos in early to mid September with this on my car!
My goal is to hit 400whp which I shouldn't have trouble with but I would like to hit 8psi at about 3500-3800 rpms if possible. I will post some videos of it on the Porsche ASAP!
Last edited by Quamen; 08-17-2008 at 06:05 PM.
08-16-2008, 03:25 PM
#6
Originally Posted by George@GTM
You know what would be awesome, a T-Trim on a stock block, with this mod to keep the boost safe, that would be a nice power curve.
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08-16-2008, 03:36 PM
#8
Very cool idea. Do you think there is anything to gain with electronic control (PWM) and not soley spring based as I would worry about cracking pressures and unwanted leakage. You could put a boost control solenoid in between? Even better, you could potentially run more PSI at midrange than the top end and control your power control via your EMS.
George, how can he overspin the blower, since it is tied to rpms? With turbos I can see this overspinning (akin to a huge boost leak). The pulley size will determine max blower speed, correct? You meant don't go too small with the pulley?
George, how can he overspin the blower, since it is tied to rpms? With turbos I can see this overspinning (akin to a huge boost leak). The pulley size will determine max blower speed, correct? You meant don't go too small with the pulley?
Last edited by rcdash; 08-16-2008 at 03:39 PM.
08-16-2008, 03:57 PM
#9
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you really shouldnt have a problem hitting 400. that'll feel nice. you'll get on boost real quick.
the smaller the pulley, the more the blower will spin.
whats the max RPM/boost the S trim is good for again?
the smaller the pulley, the more the blower will spin.
whats the max RPM/boost the S trim is good for again?
08-16-2008, 04:43 PM
#10
Originally Posted by deanfootlong
you really shouldnt have a problem hitting 400. that'll feel nice. you'll get on boost real quick.
the smaller the pulley, the more the blower will spin.
whats the max RPM/boost the S trim is good for again?
the smaller the pulley, the more the blower will spin.
whats the max RPM/boost the S trim is good for again?
08-16-2008, 04:45 PM
#11
We will see how it works and go from there. The good thing is that since this is a full billet piece there is room for adaptability. I don't think it will be that bad but I will find out soon enough.
Originally Posted by rcdash
Very cool idea. Do you think there is anything to gain with electronic control (PWM) and not soley spring based as I would worry about cracking pressures and unwanted leakage. You could put a boost control solenoid in between? Even better, you could potentially run more PSI at midrange than the top end and control your power control via your EMS.
George, how can he overspin the blower, since it is tied to rpms? With turbos I can see this overspinning (akin to a huge boost leak). The pulley size will determine max blower speed, correct? You meant don't go too small with the pulley?
George, how can he overspin the blower, since it is tied to rpms? With turbos I can see this overspinning (akin to a huge boost leak). The pulley size will determine max blower speed, correct? You meant don't go too small with the pulley?
08-16-2008, 05:55 PM
#12
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Do you know the closing pressure of the relief valve?
I think you are going to have to find a valve that will dump just the right amount of charge air without dumping too much. I can't wait to see how this goes
I think you are going to have to find a valve that will dump just the right amount of charge air without dumping too much. I can't wait to see how this goes
08-16-2008, 06:33 PM
#13
I'm definitely interested! I have the Si trim blower, but am only running the 3.33 pulley since it puts out 9 psi with a stock block. I would like to go to the 3.12 to get some extra mid-range power...since it's pretty much non existent.
How reliable will it be? If I set it to 9 psi, will it change depending on temperature? Will it wear out over a short time and need adjustment?
How reliable will it be? If I set it to 9 psi, will it change depending on temperature? Will it wear out over a short time and need adjustment?
08-16-2008, 07:45 PM
#14
Originally Posted by Quamen
I believe it is good for 55,000rpms at which point the cast impeller tip speeds start to become a problem but the bearings could handle more. I believe it is 22psi it can handle. Again impeller limited.
WHen releasing the majority of the boost and flow the blower will make . Do you think the blower will have less stress on it when over spinnning it ? Making this mod very doable . Only problem I see is when it does open , that it may release to much preasure . But only doing it will tell . Good luck ! I hope it works well . It will give SC guys more options for more power .
08-16-2008, 08:39 PM
#15
Originally Posted by rcdash
Very cool idea. Do you think there is anything to gain with electronic control (PWM) and not soley spring based as I would worry about cracking pressures and unwanted leakage. You could put a boost control solenoid in between? Even better, you could potentially run more PSI at midrange than the top end and control your power control via your EMS.
George, how can he overspin the blower, since it is tied to rpms? With turbos I can see this overspinning (akin to a huge boost leak). The pulley size will determine max blower speed, correct? You meant don't go too small with the pulley?
George, how can he overspin the blower, since it is tied to rpms? With turbos I can see this overspinning (akin to a huge boost leak). The pulley size will determine max blower speed, correct? You meant don't go too small with the pulley?
In order to do what he wants, which is produce more power at a lower rpm and bleed off the excess boost. He will need to run a much smaller pulley, doing this with out the proper research can cause the blower to over spin in the higher rpm's damaging the blower, so you have to make sure the blower you have will be operating within its design specs based on the pulley you will use and that you don't go beyond the blowers rated rpm.
How that makes sense.
Turbos can be over spun if they are too small, and revved to high as well. Although very uncommon.
08-16-2008, 08:41 PM
#16
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If wastegates work for turbos then it should be just as easy for a supercharged system to do. I have wondered about this for a long time. I guess I would over spin my blower as I don't have a T or S-trim. I was thinking though about putting a 2.87 and one of these valves to limit boost to 10 lbs. Then I thought about doing a 2.62 and the issue of over spinning my blower became a problem. I would love to see a dyno graph on one of these setups. Wow just think if this works, we could have torque!
08-16-2008, 09:12 PM
#17
Originally Posted by booger
WHen releasing the majority of the boost and flow the blower will make . Do you think the blower will have less stress on it when over spinnning it ? Making this mod very doable . Only problem I see is when it does open , that it may release to much preasure . But only doing it will tell . Good luck ! I hope it works well . It will give SC guys more options for more power .
08-16-2008, 09:15 PM
#18
Originally Posted by JonnyC
I'm definitely interested! I have the Si trim blower, but am only running the 3.33 pulley since it puts out 9 psi with a stock block. I would like to go to the 3.12 to get some extra mid-range power...since it's pretty much non existent.
How reliable will it be? If I set it to 9 psi, will it change depending on temperature? Will it wear out over a short time and need adjustment?
How reliable will it be? If I set it to 9 psi, will it change depending on temperature? Will it wear out over a short time and need adjustment?
Reliability should be excellent as the craftsmenship and engineering on this part is very good. The unit itself will not be affected by temperature change.
08-16-2008, 09:19 PM
#19
The pressure shouldn't drop below the set cracking pressure. If you set the valve to 10psi cracking pressure then if the valve starts to release enough air to lower the pressure below 10psi like 9.9psi, the valve should close and pressure will build and blow off again.
My guess is that at a certain rpm you could get flutter caused by this but the pressure should remain consistant. Again, we have had good success with our brass adjustable pressure relief valves. This is just those on a much larger scale!
My guess is that at a certain rpm you could get flutter caused by this but the pressure should remain consistant. Again, we have had good success with our brass adjustable pressure relief valves. This is just those on a much larger scale!
Originally Posted by Ahsmo
Do you know the closing pressure of the relief valve?
I think you are going to have to find a valve that will dump just the right amount of charge air without dumping too much. I can't wait to see how this goes
I think you are going to have to find a valve that will dump just the right amount of charge air without dumping too much. I can't wait to see how this goes
08-17-2008, 07:40 AM
#20
very cool man! cant wait to play around with it.
we run the T trims on both our formula d cars (350z). they are both still stock motors and are holding up like a champ. we do run all C 16 in them though.
with the 3.12 pulley on the revup setup, we see 15-16 psi on them. it makes between 450-500 depending on the tune for the conditions...
we run the T trims on both our formula d cars (350z). they are both still stock motors and are holding up like a champ. we do run all C 16 in them though.
with the 3.12 pulley on the revup setup, we see 15-16 psi on them. it makes between 450-500 depending on the tune for the conditions...