Has anyone done a VNT on a 603 yet? I have ideas
Has anyone done a VNT on a 603 yet? I have ideas
I have a non-egr, 603.97 manifold on the way from a friendly junkyard seller. This will put me at the same configuration as the 617 crowd
It will also make the oil drain on my 2256v be in the less than 30 deg. off vertical position. I'm also thinking about having the manifold ceramic coated, but I don't have a job right now, so that might have to wait. Grr.I plan on going the dual actuator route, with the vacuum actuator on the opposite side, so it is fully open with idle vacuum.
The important part:
Now, what I have found is that the hated EGR/ARV solenoids and airflow meter box system can actually be of some benefit! Connecting my mityvac to one of the smog solenoids showed that there is 17-17.5" vac available under light throttle, and at cruise, and no throttle above about 1300 rpm. After this, there is about 10 at light acceleration, and 4 at heavy accel / not moving.
THIS, at least to me, is an excellent way to have a cruise boost function. What I am thinking of doing is having one line off of the smog solenoid, and meeting another that will be off of the trans vac. A check valve will be open to allow the ARV vac to control the vanes until vac goes below 15" hg, when the valve will close and be at the discretion of the trans (throttle). I may add another valve on the trans line to keep the 17" vac from making the trans flare.
I am especially excited about this because I found that even under very light around town accel / cruise, where I wouldn't need boost, the trans vac is down to 12-10", and highway cruising it is 11-9" depending on speed. While this might not produce much boost, it would be even better if the other solenoid were holding it open fully.
The other good thing is that the vac actuator on the 2256v I have to play with is set to be fully open at exactly 17.5"!
The opposing pressure actuator will be "open" on the end where it meets the vane lever, so it will not reduce the vacuum actuator's range by making it work against the pressure spring. (PS, I still have yet to find an actuator for less than $40..any ideas?)
I still have some more testing to do, and a LOT of turbo work to do. I have considered just trying to find an HX30 or something, but I think the VNT (even a 2256) might yield better economy.
Lastly, is it right to assume that a pressure actuator's full actuation psi will be that psi, plus the force that the vac actuator spring is opposing? I.e, if the vac is at 0, but 17" hg opens it fully (which is 8.35 psi), would a 7 psi actuator then take 15.25 to fully open it?
I suppose our biggest setback is the crappy egr'd exhaust manifold. Some of the problems presented here are lack of room, odd flange angle, and no room for an opposing actuator.
I have a non-egr, 603.97 manifold on the way from a friendly junkyard seller. This will put me at the same configuration as the 617 crowd It will also make the oil drain on my 2256v be in the less than 30 deg. off vertical position. I'm also thinking about having the manifold ceramic coated, but I don't have a job right now, so that might have to wait. Grr.
I plan on going the dual actuator route, with the vacuum actuator on the opposite side, so it is fully open with idle vacuum.
The important part:
Now, what I have found is that the hated EGR/ARV solenoids and airflow meter box system can actually be of some benefit! Connecting my mityvac to one of the smog solenoids showed that there is 17-17.5" vac available under light throttle, and at cruise, and no throttle above about 1300 rpm. After this, there is about 10 at light acceleration, and 4 at heavy accel / not moving.
THIS, at least to me, is an excellent way to have a cruise boost function. What I am thinking of doing is having one line off of the smog solenoid, and meeting another that will be off of the trans vac. A check valve will be open to allow the ARV vac to control the vanes until vac goes below 15" hg, when the valve will close and be at the discretion of the trans (throttle). I may add another valve on the trans line to keep the 17" vac from making the trans flare.
I am especially excited about this because I found that even under very light around town accel / cruise, where I wouldn't need boost, the trans vac is down to 12-10", and highway cruising it is 11-9" depending on speed. While this might not produce much boost, it would be even better if the other solenoid were holding it open fully.
The other good thing is that the vac actuator on the 2256v I have to play with is set to be fully open at exactly 17.5"!
The opposing pressure actuator will be "open" on the end where it meets the vane lever, so it will not reduce the vacuum actuator's range by making it work against the pressure spring. (PS, I still have yet to find an actuator for less than $40..any ideas?)
I still have some more testing to do, and a LOT of turbo work to do. I have considered just trying to find an HX30 or something, but I think the VNT (even a 2256) might yield better economy.
Lastly, is it right to assume that a pressure actuator's full actuation psi will be that psi, plus the force that the vac actuator spring is opposing? I.e, if the vac is at 0, but 17" hg opens it fully (which is 8.35 psi), would a 7 psi actuator then take 15.25 to fully open it?
(11-20-2009, 11:39 PM)awsrock Lastly, is it right to assume that a pressure actuator's full actuation psi will be that psi, plus the force that the vac actuator spring is opposing? I.e, if the vac is at 0, but 17" hg opens it fully (which is 8.35 psi), would a 7 psi actuator then take 15.25 to fully open it?
Not quite. Actuators are usually rated at cracking pressure (when they start to move). My 5psi WG actuator actually limited boost to 8psi.
Most dual actuator applications I've seen involved opening the vacuum actuator and removing the spring.
ForcedInduction
11-21-2009, 01:15 AM
#2
Sounds like a good plan.
(11-20-2009, 11:39 PM)awsrock Lastly, is it right to assume that a pressure actuator's full actuation psi will be that psi, plus the force that the vac actuator spring is opposing? I.e, if the vac is at 0, but 17" hg opens it fully (which is 8.35 psi), would a 7 psi actuator then take 15.25 to fully open it?
Not quite. Actuators are usually rated at cracking pressure (when they start to move). My 5psi WG actuator actually limited boost to 8psi.
Most dual actuator applications I've seen involved opening the vacuum actuator and removing the spring.
(11-21-2009, 01:15 AM)ForcedInduction Not quite. Actuators are usually rated at cracking pressure (when they start to move). My 5psi WG actuator actually limited boost to 8psi.
Most dual actuator applications I've seen involved opening the vacuum actuator and removing the spring.
So would removing the spring in the vacumm actuator still allow it to function the same, just be working against the pressure spring?
I was thinking of getting an actuator that cracks at 5 psi, too, since I don't have any need to go above 14-15 psi for now. I have only seen some that crack at 3 and open at 7, or others that are rated too high.
(11-21-2009, 01:15 AM)ForcedInduction Not quite. Actuators are usually rated at cracking pressure (when they start to move). My 5psi WG actuator actually limited boost to 8psi.
Most dual actuator applications I've seen involved opening the vacuum actuator and removing the spring.
So would removing the spring in the vacumm actuator still allow it to function the same, just be working against the pressure spring?
I was thinking of getting an actuator that cracks at 5 psi, too, since I don't have any need to go above 14-15 psi for now. I have only seen some that crack at 3 and open at 7, or others that are rated too high.
ForcedInduction
11-21-2009, 08:15 PM
#4
Yes. In a dual system, both springs are working together as one. It would be like having a 14psi spring instead of 5psi.
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