There are a lot of BOV options out there but the 1g BOV is hard to beat for it's price, function, and holding capacity. It's one drawback is that it will begin cracking open around 20psi. Until now there were really only three ways to address this (well, four if you count the Dejon Tool valve but that is no longer available so I'm leaving it out of this writeup).
1) Crushing the valve - Effective for holding more boost but can cause some problems with function.
2) Dodge Garage mod - Also effective but also sacrifices drivability in other areas.
3) If you have ECMLink you can use Nitrous Controls: More info' here
This write up simply modifies the Garage mod method by using a regulator to limit boost to the bottom of the lifting diaphram.
The first step is to do the Dodge Mod. Here is the site but I used a 1/8" npt barb where they suggest some kind of tubing. It's up to you how you want to do yours. You also need to install a barb fitting in your UIC near the BOV.
DDG- Talon BOV mod for HIGH BOOST
Parts needed:
The stock BOV has three areas that are affected by boost and vacuum.
1) The bottom of the valve opening
2) The bottom of the valve diaphram
3) The top of the valve diaphram
See the diagram below.
As you can see the boost pressure is applied to the bottom and top of the valve when the throttle body is open. Theoretically you would think this should equalize the pressure on the valve and to some degree it does. There is also a spring helping to hold the valve closed. However, in the real world there is ultimately more pressure applied to the bottom of the valve compared to the top and at around 20psi the valve will begin to crack open.
The Dodge / Garage mod raises the holding capacity of the 1g BOV by blocking the side passage that routes air to the bottom of the lifting diaphram effectively reducing the upward pressure to only what is applied to the valve opening. Although this works, it causes some drivability issues on the street and commonly a boost source is tapped on the UIC pipe to reconnect the bottom of the diaphram with a piece of vacuum hose for street driving. When you want to turn up the boost for the track, you just remove the hose and block the UIC tap. See image below:
But.... what if you want to keep that higher boost setting for the street?
This is where adding the regulator comes in. By limiting the boost that the bottom of the diaphram sees to 15psi, we keep the OEM function but increase the holding capacity at the same time.
Setting up the regulator:
If you look on the bottom of the regulator there is an arrow pointing inward. This is the inlet. There are 4 ports total (one on each side); the other three can all be used as outlets. We will be only using one inlet and one outlet. The other two ports will be plugged when mounted in the car. During calibration, we will temporarily use one of the holes to be plugged for the 30psi gauge.
To have both 1/8" barbs facing forward, install one of the 1/8" barbs into the regulator inlet and then put the 1/8"npt 90* street elbow into one side of the regulator with the opening facing the same direction as the inlet barb (see pic's at bottom of page).
Next install a 1/8" barb into the 90* fitting. You should now have two barbs facing foward.
Install a plug into one hole and your gauge into the other (to be replaced with a plug after calibration)
Using a compressor (set outlet pressure to ~ 30psi) apply air pressure to the regulator inlet and dial in 15psi. You have to lift the regulators handle to turn it and once you have the pressure set, push it down to lock it into position.
Remove the gauge, install a plug and you're regulator is ready to use. Be sure to mount your regulator so that your lines are as short as possible.
See Below:
It's really quite simple and best of all.. it works great.
On my 2g I mounted the regulator between the fuse box and cruise control actuator.
1) Crushing the valve - Effective for holding more boost but can cause some problems with function.
2) Dodge Garage mod - Also effective but also sacrifices drivability in other areas.
3) If you have ECMLink you can use Nitrous Controls: More info' here
This write up simply modifies the Garage mod method by using a regulator to limit boost to the bottom of the lifting diaphram.
The first step is to do the Dodge Mod. Here is the site but I used a 1/8" npt barb where they suggest some kind of tubing. It's up to you how you want to do yours. You also need to install a barb fitting in your UIC near the BOV.
DDG- Talon BOV mod for HIGH BOOST
Parts needed:
- Miniature Air Regulator - 25 PSI - McMaster Part #6746K17
- Mounting Bracket - McMaster Part #6763K21
- 30psi Pressure Gauge - McMaster Part #3846K1
- (4x) 1/8" npt barbed fittings
- (1x) 1/8" npt 90* street elbow
- (2x) 1/8" npt plugs
- 1-2' of vacuum line
The stock BOV has three areas that are affected by boost and vacuum.
1) The bottom of the valve opening
2) The bottom of the valve diaphram
3) The top of the valve diaphram
See the diagram below.
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As you can see the boost pressure is applied to the bottom and top of the valve when the throttle body is open. Theoretically you would think this should equalize the pressure on the valve and to some degree it does. There is also a spring helping to hold the valve closed. However, in the real world there is ultimately more pressure applied to the bottom of the valve compared to the top and at around 20psi the valve will begin to crack open.
The Dodge / Garage mod raises the holding capacity of the 1g BOV by blocking the side passage that routes air to the bottom of the lifting diaphram effectively reducing the upward pressure to only what is applied to the valve opening. Although this works, it causes some drivability issues on the street and commonly a boost source is tapped on the UIC pipe to reconnect the bottom of the diaphram with a piece of vacuum hose for street driving. When you want to turn up the boost for the track, you just remove the hose and block the UIC tap. See image below:
You must be logged in to view this image or video.
But.... what if you want to keep that higher boost setting for the street?
This is where adding the regulator comes in. By limiting the boost that the bottom of the diaphram sees to 15psi, we keep the OEM function but increase the holding capacity at the same time.
Setting up the regulator:
If you look on the bottom of the regulator there is an arrow pointing inward. This is the inlet. There are 4 ports total (one on each side); the other three can all be used as outlets. We will be only using one inlet and one outlet. The other two ports will be plugged when mounted in the car. During calibration, we will temporarily use one of the holes to be plugged for the 30psi gauge.
To have both 1/8" barbs facing forward, install one of the 1/8" barbs into the regulator inlet and then put the 1/8"npt 90* street elbow into one side of the regulator with the opening facing the same direction as the inlet barb (see pic's at bottom of page).
Next install a 1/8" barb into the 90* fitting. You should now have two barbs facing foward.
Install a plug into one hole and your gauge into the other (to be replaced with a plug after calibration)
Using a compressor (set outlet pressure to ~ 30psi) apply air pressure to the regulator inlet and dial in 15psi. You have to lift the regulators handle to turn it and once you have the pressure set, push it down to lock it into position.
Remove the gauge, install a plug and you're regulator is ready to use. Be sure to mount your regulator so that your lines are as short as possible.
See Below:
You must be logged in to view this image or video.
It's really quite simple and best of all.. it works great.
On my 2g I mounted the regulator between the fuse box and cruise control actuator.
You must be logged in to view this image or video.
You must be logged in to view this image or video.
Last edited:
