Forge BOV review
Jan 3, 2005, 08:41 PM
#19
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OK, here are my thoughts:
The blue spring won't necessarily create compressor surging unless it is stiffer than the amount of boost that the car is currently making. In that instance, it will not fully allow the air to pass through the valve which can create some minor surging effects.
I would only recommend to use a stiffer spring if the current spring being used is not able to hold the requested amount of boost under FULL THROTTLE throttle lift.
PART THROTTLE throttle lift is a different story altogether and is what you will experience the effects of in part throttle conditions. What you are experiencing is the inconsistent pressure differential between the pressure side of the valve and the vacuum line. This inconsistent valve response come from the "hesitant" throttle input that the driver is providing, or so the car thinks.
This bucking or hesitation that you are feeling is a common occurance with almost all single-piston or single-diaphragm valves and is vitually unavoidable. The OEM valve does not have this problem as the 3 chambers in the valve allow for more "fluidic" movement and consistent response of the valve. It is very difficult for us to duplicate the operation and design of the OEM valve, so this is why we are looking to utilize the dual-pistons from the atmospheric valve in the body of the recirc. valve.
The design will allow the main piston to open under vacuum, but the secondary piston will remain closed keeping the intake air in the intake side of the system. When it is required that both pistons open to vent the charge air back into the intake side, both pistons will be forced open by the positive pressure. We are hoping that this will still maintain the recirc. function of the valve but will allow for smoother operation.
This will also require the installation of the valve with the bottom port connected to the pressure side and the side port connected to the intake hose. This is absolutely necessary to allow the dual counterbalanced pistons to function proper, where as the single piston valves can be installed in either orientation.
I have a gentleman testing a version of this valve on his '03 (I think) Evo at this time, but I have not had a chance to talk to him over the holidays to get his input. This is something I hope to do in the next day or so.
The shims included with the valves will only be used for minor adjustment of the pre-load on each spring when installed in the valve. We recommend using a maximum of only 2 shims when adjusting the pre-load. If you feel that you require additional stiffness above and beyond a given spring and 2 shims, just use the next spring up.
The blue spring won't necessarily create compressor surging unless it is stiffer than the amount of boost that the car is currently making. In that instance, it will not fully allow the air to pass through the valve which can create some minor surging effects.
I would only recommend to use a stiffer spring if the current spring being used is not able to hold the requested amount of boost under FULL THROTTLE throttle lift.
PART THROTTLE throttle lift is a different story altogether and is what you will experience the effects of in part throttle conditions. What you are experiencing is the inconsistent pressure differential between the pressure side of the valve and the vacuum line. This inconsistent valve response come from the "hesitant" throttle input that the driver is providing, or so the car thinks.
This bucking or hesitation that you are feeling is a common occurance with almost all single-piston or single-diaphragm valves and is vitually unavoidable. The OEM valve does not have this problem as the 3 chambers in the valve allow for more "fluidic" movement and consistent response of the valve. It is very difficult for us to duplicate the operation and design of the OEM valve, so this is why we are looking to utilize the dual-pistons from the atmospheric valve in the body of the recirc. valve.
The design will allow the main piston to open under vacuum, but the secondary piston will remain closed keeping the intake air in the intake side of the system. When it is required that both pistons open to vent the charge air back into the intake side, both pistons will be forced open by the positive pressure. We are hoping that this will still maintain the recirc. function of the valve but will allow for smoother operation.
This will also require the installation of the valve with the bottom port connected to the pressure side and the side port connected to the intake hose. This is absolutely necessary to allow the dual counterbalanced pistons to function proper, where as the single piston valves can be installed in either orientation.
I have a gentleman testing a version of this valve on his '03 (I think) Evo at this time, but I have not had a chance to talk to him over the holidays to get his input. This is something I hope to do in the next day or so.
The shims included with the valves will only be used for minor adjustment of the pre-load on each spring when installed in the valve. We recommend using a maximum of only 2 shims when adjusting the pre-load. If you feel that you require additional stiffness above and beyond a given spring and 2 shims, just use the next spring up.
Jan 3, 2005, 09:13 PM
#20
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Originally Posted by Mike@Forge
OK, here are my thoughts:
The blue spring won't necessarily create compressor surging unless it is stiffer than the amount of boost that the car is currently making. In that instance, it will not fully allow the air to pass through the valve which can create some minor surging effects.
I would only recommend to use a stiffer spring if the current spring being used is not able to hold the requested amount of boost under FULL THROTTLE throttle lift.
The blue spring won't necessarily create compressor surging unless it is stiffer than the amount of boost that the car is currently making. In that instance, it will not fully allow the air to pass through the valve which can create some minor surging effects.
I would only recommend to use a stiffer spring if the current spring being used is not able to hold the requested amount of boost under FULL THROTTLE throttle lift.
Originally Posted by Mike@Forge
PART THROTTLE throttle lift is a different story altogether and is what you will experience the effects of in part throttle conditions. What you are experiencing is the inconsistent pressure differential between the pressure side of the valve and the vacuum line. This inconsistent valve response come from the "hesitant" throttle input that the driver is providing, or so the car thinks.
This bucking or hesitation that you are feeling is a common occurance with almost all single-piston or single-diaphragm valves and is vitually unavoidable. The OEM valve does not have this problem as the 3 chambers in the valve allow for more "fluidic" movement and consistent response of the valve. It is very difficult for us to duplicate the operation and design of the OEM valve, so this is why we are looking to utilize the dual-pistons from the atmospheric valve in the body of the recirc. valve.
The design will allow the main piston to open under vacuum, but the secondary piston will remain closed keeping the intake air in the intake side of the system. When it is required that both pistons open to vent the charge air back into the intake side, both pistons will be forced open by the positive pressure. We are hoping that this will still maintain the recirc. function of the valve but will allow for smoother operation.
This will also require the installation of the valve with the bottom port connected to the pressure side and the side port connected to the intake hose. This is absolutely necessary to allow the dual counterbalanced pistons to function proper, where as the single piston valves can be installed in either orientation.
This bucking or hesitation that you are feeling is a common occurance with almost all single-piston or single-diaphragm valves and is vitually unavoidable. The OEM valve does not have this problem as the 3 chambers in the valve allow for more "fluidic" movement and consistent response of the valve. It is very difficult for us to duplicate the operation and design of the OEM valve, so this is why we are looking to utilize the dual-pistons from the atmospheric valve in the body of the recirc. valve.
The design will allow the main piston to open under vacuum, but the secondary piston will remain closed keeping the intake air in the intake side of the system. When it is required that both pistons open to vent the charge air back into the intake side, both pistons will be forced open by the positive pressure. We are hoping that this will still maintain the recirc. function of the valve but will allow for smoother operation.
This will also require the installation of the valve with the bottom port connected to the pressure side and the side port connected to the intake hose. This is absolutely necessary to allow the dual counterbalanced pistons to function proper, where as the single piston valves can be installed in either orientation.
Jan 3, 2005, 09:19 PM
#21
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One thing that would be nice to add to the Forge BOV is an adjustment screw. Move the vaccum nipple to the side or offset from the center and use a 10 mm bolt and locknut to adjust the pressure on the spring. This would allow for easy tuning. I will probably be doing this to my BOV in the future as tuning by replacing springs and adding shims is time consuming and basically sucks.
Jan 4, 2005, 08:31 AM
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To jj,
Yes, there is a secondary spring for the secondary piston that is counter balanced against the main piston. This spring keeps the secondary piston closed at vacuum. We also have different versions of this secondary spring that will be tested to see which offers the best response of the secondary piston.
To mhutch,
For our existing valve lineup, we will not be altering the components to add any type of twist adjustment. The interchangeable springs we offer are used on over 30 different valves that we make, so those will remain in use. As consolation, we do have a separate top half to the valve that has a side vacuum port that is mostly used for Eclipse applications. This is easily adapted to the Evo valve as they use the same bottom half of the body. The all-new valve which we will be releasing will have a twist adjustment AND a side vacuum port that swivels around the body of the valve for perfect placement AND will only utilize one spring that will never be replaced or changed. This valve will also incorporate numerous other features to set it apart from the competition.
To Zeus,
At this time, there are no current plans to offer the internals separately as there may also be required changes to the body of the valve as well, though don't rule it out. If we are able to adapt the dual-pistons to the existing recirc. body with no changes to the body, then, yes, we MAY offer the internals separately to upgrade an older valve. But, again, we are still designing and testing this.
Yes, there is a secondary spring for the secondary piston that is counter balanced against the main piston. This spring keeps the secondary piston closed at vacuum. We also have different versions of this secondary spring that will be tested to see which offers the best response of the secondary piston.
To mhutch,
For our existing valve lineup, we will not be altering the components to add any type of twist adjustment. The interchangeable springs we offer are used on over 30 different valves that we make, so those will remain in use. As consolation, we do have a separate top half to the valve that has a side vacuum port that is mostly used for Eclipse applications. This is easily adapted to the Evo valve as they use the same bottom half of the body. The all-new valve which we will be releasing will have a twist adjustment AND a side vacuum port that swivels around the body of the valve for perfect placement AND will only utilize one spring that will never be replaced or changed. This valve will also incorporate numerous other features to set it apart from the competition.
To Zeus,
At this time, there are no current plans to offer the internals separately as there may also be required changes to the body of the valve as well, though don't rule it out. If we are able to adapt the dual-pistons to the existing recirc. body with no changes to the body, then, yes, we MAY offer the internals separately to upgrade an older valve. But, again, we are still designing and testing this.
Last edited by Mike@Forge; Jan 4, 2005 at 08:34 AM.
Jan 4, 2005, 04:50 PM
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Well, I have some disappointing news for those of you who are interested!
I just met up with the gentleman who was doing the testing for me and I was disappointed to say the least.
It turns out, dual counter-balanced pistons in a recirc. valve don't work as I thought they would.
It actually had the exact opposite effect as what I thought would happen. It actually caused the car to stall before any throttle was even applied, so this is something that we will not be implementing into our valve line-up.
At this point, I am not sure how we will approach the hesitation concerns at part throttle when using a recirc. valve. I haven't yet figured out how we can design a 3-chambered valve like the OEM valve.
The all-new valve we will be releasing will soon be tested on another EvoM member's car in a single piston recirc. configuration and I expect it to operate at least equally to the existing recirc. valve if not marginally better. This person and I will bring you all the information that we are able to come up with.
I will continue to look into the hesitation situation though and how we can approach creating an adjustable recirc. valve that eliminates it completely.
I sincerely appreciate everyone's input in the matter and I'll keep you all up to date!
Thanks for your time!
I just met up with the gentleman who was doing the testing for me and I was disappointed to say the least.
It turns out, dual counter-balanced pistons in a recirc. valve don't work as I thought they would.
It actually had the exact opposite effect as what I thought would happen. It actually caused the car to stall before any throttle was even applied, so this is something that we will not be implementing into our valve line-up.
At this point, I am not sure how we will approach the hesitation concerns at part throttle when using a recirc. valve. I haven't yet figured out how we can design a 3-chambered valve like the OEM valve.
The all-new valve we will be releasing will soon be tested on another EvoM member's car in a single piston recirc. configuration and I expect it to operate at least equally to the existing recirc. valve if not marginally better. This person and I will bring you all the information that we are able to come up with.
I will continue to look into the hesitation situation though and how we can approach creating an adjustable recirc. valve that eliminates it completely.
I sincerely appreciate everyone's input in the matter and I'll keep you all up to date!
Thanks for your time!
Jan 4, 2005, 04:57 PM
#27
Originally Posted by Appauldd
The only time my Forge valve causes problems is at highway speeds when I am in the throttle and let off slowly.....the car jitters and bucks a bit. I have the yellow spring in the valve, and my boost is rock steady at 21 psi. There is no problem if I let off the throttle quickly.
Mike@Forge....what are your thoughts on this????
Mike@Forge....what are your thoughts on this????
I love my forge valve and I have the same issue that you have exactly. I thought its a missfire but I think I am wrong. I think its a mix between turbo surge and the valve. well at 30 PSI you have to feel the jerk
Jan 4, 2005, 04:58 PM
#28
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Like I said on the phone and in this thread (and other members resounded) - thanks for trying and keep up the good work with R&D; but as it stands right now - they work pretty well, so no complaints (at least from me 
)
)
Jan 4, 2005, 05:05 PM
#29
Originally Posted by Mike@Forge
Well, I have some disappointing news for those of you who are interested!
I just met up with the gentleman who was doing the testing for me and I was disappointed to say the least.
It turns out, dual counter-balanced pistons in a recirc. valve don't work as I thought they would.
It actually had the exact opposite effect as what I thought would happen. It actually caused the car to stall before any throttle was even applied, so this is something that we will not be implementing into our valve line-up.
At this point, I am not sure how we will approach the hesitation concerns at part throttle when using a recirc. valve. I haven't yet figured out how we can design a 3-chambered valve like the OEM valve.
The all-new valve we will be releasing will soon be tested on another EvoM member's car in a single piston recirc. configuration and I expect it to operate at least equally to the existing recirc. valve if not marginally better. This person and I will bring you all the information that we are able to come up with.
I will continue to look into the hesitation situation though and how we can approach creating an adjustable recirc. valve that eliminates it completely.
I sincerely appreciate everyone's input in the matter and I'll keep you all up to date!
Thanks for your time!
I just met up with the gentleman who was doing the testing for me and I was disappointed to say the least.
It turns out, dual counter-balanced pistons in a recirc. valve don't work as I thought they would.
It actually had the exact opposite effect as what I thought would happen. It actually caused the car to stall before any throttle was even applied, so this is something that we will not be implementing into our valve line-up.
At this point, I am not sure how we will approach the hesitation concerns at part throttle when using a recirc. valve. I haven't yet figured out how we can design a 3-chambered valve like the OEM valve.
The all-new valve we will be releasing will soon be tested on another EvoM member's car in a single piston recirc. configuration and I expect it to operate at least equally to the existing recirc. valve if not marginally better. This person and I will bring you all the information that we are able to come up with.
I will continue to look into the hesitation situation though and how we can approach creating an adjustable recirc. valve that eliminates it completely.
I sincerely appreciate everyone's input in the matter and I'll keep you all up to date!
Thanks for your time!
Thank you so much for the great info. Would this hesitation cause the turbo to fail? in other words will it efect the turbo in any way?. I get the hesitation only on 5th gear under heavy load once i let off the gas slowly. Its strong hesitation and you can feel the whole car jerking. It happenes on 10 psi and above. If I let off the gas all at once its all good. I do boost up to 30 psi on race gas and around 24~ 23 on pump.
Thank you
Jan 4, 2005, 05:08 PM
#30
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Thanks! 
That's much appreciated, but I'm the type of person who strives for perfection in all situations. The problem seems to be widespread enough to cause many people some headaches so i'd like to eliminate that as much as possible.
We won't give up.
I'm just looking for us to be able to create the "ultimate" valve!
We'll see how that goes!
That's much appreciated, but I'm the type of person who strives for perfection in all situations. The problem seems to be widespread enough to cause many people some headaches so i'd like to eliminate that as much as possible.
We won't give up.
I'm just looking for us to be able to create the "ultimate" valve!
We'll see how that goes!