In that case you should vent it back to the front of the throttle body.
You don't want Methanol going out to the open air.
What is the supercharger drive ratio?
M112 - 300 Build for the '56
- Thread starter clintonvillian
- Start date
You don't want Methanol going out to the open air.
What is the supercharger drive ratio?
clintonvillian
Famous Member
2.67:1
clintonvillian
Famous Member
If I go with the biggest pulley available I can get it to 2.5:1
On paper a 2.67 drive ratio is close to 14.5 lbs of peak boost but the 300 six with a big cam and a ported big valve head probably has a better volumetric efficiency than the Eaton 112 at that pressure level so the boost may be less.
Does the supercharger have a bypass valve?
Does the supercharger have a bypass valve?
clintonvillian
Famous Member
Yes, when vacuum is seen, it will open.
Im not sure a BOV is really what I want or even necessary. Id just feel more comfortable being able to limit the boost. I thought a BOV would do it, but the more I read...
I almost need a BOV from an air compressor or something..
clintonvillian
Famous Member
Any recommendations on brands?
I've always worked with TiAL.
A 38mm gate should be plenty.
Turbosmart would be my other choice
They have a better spring selection that TiAL
You could use their 5 lb spring as a base and use a variable low pressure air regulator in the cab to feed the top wastegate port so you could increase or vary the boost on the fly.
A 38mm gate should be plenty.
Turbosmart would be my other choice
They have a better spring selection that TiAL
You could use their 5 lb spring as a base and use a variable low pressure air regulator in the cab to feed the top wastegate port so you could increase or vary the boost on the fly.
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Sevensecondsuv
Well-known member
How are you going to use a wastegate to control boost? Are you going to mount it in the intake?
Seems to me a better option would be a bigger pulley on the S/C. That way you're not driving it faster than you need for your desired boost level and creating a bunch of extra heat.
Also, it's your build and you needn't pay any attention to my unsolicited opinions, but I'd do a simple air/air intercooler before messing with methanol injection. You've already got the supercharger mounted remote from the intake manifold so it'd only be a matter of piping it in....
Seems to me a better option would be a bigger pulley on the S/C. That way you're not driving it faster than you need for your desired boost level and creating a bunch of extra heat.
Also, it's your build and you needn't pay any attention to my unsolicited opinions, but I'd do a simple air/air intercooler before messing with methanol injection. You've already got the supercharger mounted remote from the intake manifold so it'd only be a matter of piping it in....
clintonvillian
Famous Member
I agree with the pulley.
Largest pulley off the shelf is 3.1". Id have to have a custom one made. It's doable but not something I want to invest in until I actually see where the system is at....for the most part everything here is just a good guess.
Wastegate will be mounted on the the pipe sticking up behind the S/C.
I had intentions of running air to air. Not enough room to het it in the front of the 56. I don't think I will be hot enough to need much cooling. So the water/meth is a pretty simple setup to trade off.
You mount the wastegate on the pipe after the supercharger and vent it back to the throttle body.
The bottom port boost reference line also connects to the same pipe.
The wastegate will begin to open as the pressure approaches the spring pressure and will regulate the pressure at that point.
You can use a 3, 5, or 7 lb spring as a base line pressure.
If you add a 0 to 15 psi air pressure regulator and connect it to the top port of the wastegate you can increase the boost above base with a twist of the regulator knob.
The decreased pressure from the wastegate will also decrease the heat so no need to decrease the drive ratio and decrease maximum boost available.
So I disagree with decreasing the supercharger drive ratio when you can simply change the boost pressure with a twist of a knob.
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Firepower354
Famous Member
How about using the stock internal bypass controlled by a boost-referenced actuator instead of vacuum?
That's possible but then you can't use it as a bypass when you want to cruise without boost.
Firepower354
Famous Member
After revisiting, aren't the actuators dual-acting diaphragms?
Yes
Top port for vacuum reference to open the bypass valve and the bottom port to deactivate the actuator by the PCM in case it needs to kill boost for whatever reason.
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clintonvillian
Famous Member
Okay so, we have a solution???
I think Holley can control the actuator...but where do I find one?
I don't understand why one vacuum line is running to the intake pre throttle body? It looks like it would see constant vacuum, and hold the valve open all the time?
I think Holley can control the actuator...but where do I find one?
I don't understand why one vacuum line is running to the intake pre throttle body? It looks like it would see constant vacuum, and hold the valve open all the time?
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clintonvillian
Famous Member
To find an actuator Google "M112 bypass valve actuator"
It is used with vacuum lines after the throttle body.
There is not enough vacuum to operate the actuator pre- throttle body plus the vacuum increases with throttle opening at pre-throttle body which is opposite of what is needed.
The Holley HP has the ability to control boost but it requires dual solenoids with a pressure sensor and works best with a higher, constant pressure source.
It also requires a higher volume than what is in the M112 actuator and a place for the pressure sensor to screw in directly.
In other words the Holley boost control is set up to work with a wastegate but not a small actuator.
I used the same type of boost control on our turbo race cars because it allows programmable boost over time so I could increase the boost gradually from launch.
The bypass actuator can probably be used to control boost with an air pressure regulator similar to the previous mentioned method but then you loose the ability to bypass during cruising.
You will need to get an actuator first to know how much spring pressure it has.
I would use the M112 actuator for bypass during cruising and the wastegate and air pressure regulator combination for boost control.
It also requires a higher volume than what is in the M112 actuator and a place for the pressure sensor to screw in directly.
In other words the Holley boost control is set up to work with a wastegate but not a small actuator.
I used the same type of boost control on our turbo race cars because it allows programmable boost over time so I could increase the boost gradually from launch.
The bypass actuator can probably be used to control boost with an air pressure regulator similar to the previous mentioned method but then you loose the ability to bypass during cruising.
You will need to get an actuator first to know how much spring pressure it has.
I would use the M112 actuator for bypass during cruising and the wastegate and air pressure regulator combination for boost control.
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Firepower354
Famous Member
In OE use, it looks like the vacuum side of the actuator, is hooked between TB and SC, with no other input?
Between spring tension, preload, arm length/angle, it should allow for a passive off-boost bypass, no?
Between spring tension, preload, arm length/angle, it should allow for a passive off-boost bypass, no?
