how do blower restrictors work?
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how do blower restrictors work?
I've read a few posts about using a smaller pulley on a centri blower to get boost to come in sooner, but then using a restrictor to limit overall boost?
How does this work?
Does the boost curve flat line and carry a certain PSI in the upper rpms?
Can restrictors be applied to any blower?
I have a D-1SC w/ a huge 4.75" pulley that's making 9psi w/ my custom intake. I'd love to pulley down but restrict the blower if it would help torque and still make 9psi and the same whp up top.
How does this work?
Does the boost curve flat line and carry a certain PSI in the upper rpms?
Can restrictors be applied to any blower?
I have a D-1SC w/ a huge 4.75" pulley that's making 9psi w/ my custom intake. I'd love to pulley down but restrict the blower if it would help torque and still make 9psi and the same whp up top.
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I feel like the procharger kit kind of did come with a restrictor... the standard molded plastic inlet.
With the procharger inlet the car made ~7.5psi. With the inlet removed it made ~9psi, and with my new 4" intake it still makes ~9psi.
I'm curious if I put the original inlet back on, lost that psi, then pullied back down to get to ~9psi again if it's going to help low end torque by making the system less efficient.
With the procharger inlet the car made ~7.5psi. With the inlet removed it made ~9psi, and with my new 4" intake it still makes ~9psi.
I'm curious if I put the original inlet back on, lost that psi, then pullied back down to get to ~9psi again if it's going to help low end torque by making the system less efficient.
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A restrictor can be used on any type of centri, however it takes a bit of trial and error to figure the exact size needed. A 1/16" will add at least a lb of boost, but there are variables to that too. What pulley your starting with and so on.
If you go too small you will have excessive drop off in the upper RPM's. It's not rocket science, but it could take a while to get it just right for your application.
If you go too small you will have excessive drop off in the upper RPM's. It's not rocket science, but it could take a while to get it just right for your application.
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I'd love to get something like that working... pulley it down for 14 psi and set the wastegate at 9psi to bleed off the boost pressure so the motor only sees 9, but sees it from ~5500-6500 for example instead of from 6490-6500.
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Do they make a bov style wastegate to vent air from the charge pipes? Or are people adapting exhaust wastegates?
I'd love to get something like that working... pulley it down for 14 psi and set the wastegate at 9psi to bleed off the boost pressure so the motor only sees 9, but sees it from ~5500-6500 for example instead of from 6490-6500.
I'd love to get something like that working... pulley it down for 14 psi and set the wastegate at 9psi to bleed off the boost pressure so the motor only sees 9, but sees it from ~5500-6500 for example instead of from 6490-6500.
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I'm actually really intrigued by the wastegate setup.
I assume a tial 38mm would do the job? They're pretty cheap and it wouldn't be hard to fab a flange onto my existing intercooler pipe. Just need to tap a vacuum source.
It would need to be retuned, but probably just fuel tweaks to add more earlier in the rpm range.
I guess I just don't see the noticeable benefit of the restrictor plate. Does anyone have a before/after dyno w/ boost logged?
Even if you used a restrictor, it can't create the turbo-like boost plateau, which is a major draw of the wastegate setup... it should increase power all across the curve instead of the 'peaky' centri power curve.
I assume a tial 38mm would do the job? They're pretty cheap and it wouldn't be hard to fab a flange onto my existing intercooler pipe. Just need to tap a vacuum source.
It would need to be retuned, but probably just fuel tweaks to add more earlier in the rpm range.
I guess I just don't see the noticeable benefit of the restrictor plate. Does anyone have a before/after dyno w/ boost logged?
Even if you used a restrictor, it can't create the turbo-like boost plateau, which is a major draw of the wastegate setup... it should increase power all across the curve instead of the 'peaky' centri power curve.
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I'm actually really intrigued by the wastegate setup.
I assume a tial 38mm would do the job? They're pretty cheap and it wouldn't be hard to fab a flange onto my existing intercooler pipe. Just need to tap a vacuum source.
It would need to be retuned, but probably just fuel tweaks to add more earlier in the rpm range.
I guess I just don't see the noticeable benefit of the restrictor plate. Does anyone have a before/after dyno w/ boost logged?
Even if you used a restrictor, it can't create the turbo-like boost plateau, which is a major draw of the wastegate setup... it should increase power all across the curve instead of the 'peaky' centri power curve.
I assume a tial 38mm would do the job? They're pretty cheap and it wouldn't be hard to fab a flange onto my existing intercooler pipe. Just need to tap a vacuum source.
It would need to be retuned, but probably just fuel tweaks to add more earlier in the rpm range.
I guess I just don't see the noticeable benefit of the restrictor plate. Does anyone have a before/after dyno w/ boost logged?
Even if you used a restrictor, it can't create the turbo-like boost plateau, which is a major draw of the wastegate setup... it should increase power all across the curve instead of the 'peaky' centri power curve.
The waste gate set up is great, but the restrictor plate has the same "draw" as the waste gate, just not quite as flat. You get the low end of a smaller puller, while it flat lines the top end boost. Taking the peak off basically.
If you have the means though, a waste gate works great.
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Actually, I guess I kind of have one... This is my dyno of the original procharger inlet vs. no inlet. So basically a pre-blower restriction of 1.5psi. Power and torque everywhere seem down, where based on the theory of a restrictor I would expect the same bottem end torque?
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The waste gate set up is great, but the restrictor plate has the same "draw" as the waste gate, just not quite as flat. You get the low end of a smaller puller, while it flat lines the top end boost. Taking the peak off basically.
If you have the means though, a waste gate works great.
If you have the means though, a waste gate works great.
I'm just struggling to picture the restrictor plate bringing in torque earlier and flattening the boost curve up top.
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Actually, I guess I kind of have one... This is my dyno of the original procharger inlet vs. no inlet. So basically a pre-blower restriction of 1.5psi. Power and torque everywhere seem down, where based on the theory of a restrictor I would expect the same bottem end torque? .
I have a t-trim with a 3.6 pulley that makes 10-11 psi up top. ECS uses a restrictor plate and (I think) a 3.25 pulley on their base kit that uses the same head unit to make ~9 psi?
Really is the same concept as a wastegate. Pulley down for more low end boost, but limit the airflow/boost on the top end.
If you are really interested in the wastegate idea, there was just an article on it in my latest gm high tech performance issue. Might want to hit up the shop doing the install for the article.
Last edited by Streetk14; Nov 17, 2011 at 06:52 PM.
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It won't. The whole concept works because you put a much smaller pulley on at the same time. The pulley/plate combo work together to alter the boost curve.
Adding a restrictor plate to a given pulley/blower combo is not going to boost power down low. For that you need to change the pulley.
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It won't. The whole concept works because you put a much smaller pulley on at the same time. The pulley/plate combo work together to alter the boost curve.
Adding a restrictor plate to a given pulley/blower combo is not going to boost power down low. For that you need to change the pulley.
Adding a restrictor plate to a given pulley/blower combo is not going to boost power down low. For that you need to change the pulley.
Well... I just mean that with the same size pulley with and without restriction the power and torque is lower or higher accordingly.
Even if I pulley down with a restrictor and pick up power/torque, it would have to be enough to overcome the deficit and then make additional power.
This may be possible, but it would be a fairly sizeable gain. I would just like to see an example of it working.