Restrictor plates
Thread Starter
Burning Brakes
Joined: Aug 2008
Posts: 906
Likes: 2
From: The Woodlands TX
Restrictor plates
OK I keep hearing about restrictor plates and forced induction. Can someone please tell me how they work other than restriction and what the benefit is and what the downside is.
Thanks
Thanks
Burning Brakes
Joined: Aug 2008
Posts: 901
Likes: 3
From: West Palm Beach FL
I believe that ECS SC kits have them. Ive noticed if you look at the big 3 SC kits that most people go with ECS usually has equal hp to tq. I like there kit becuase you get alot of power down low. Im pretty sure that the other kits can do this as well. Not really sure how it works. I would like to know as well. All 3 kits are proven winners so you can't really go wrong with any of them
Last edited by Zo6BEAST; Mar 15, 2009 at 08:47 PM.
Racer
Joined: Jun 2006
Posts: 327
Likes: 12
From: Carlsbad California
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Last edited by thomas walters; Mar 15, 2009 at 10:56 PM.
Thread Starter
Burning Brakes
Joined: Aug 2008
Posts: 906
Likes: 2
From: The Woodlands TX
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Burning Brakes
Joined: Aug 2008
Posts: 901
Likes: 3
From: West Palm Beach FL
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Racer
Joined: Jan 2008
Posts: 476
Likes: 1
From: New York
Nice write-up thank you. How much does a restrictor plate cost?
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Melting Slicks
Joined: May 2008
Posts: 2,377
Likes: 18
From: Fresno Ca
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Racer
Joined: Jun 2006
Posts: 327
Likes: 12
From: Carlsbad California
I do not have a restrictor plate yet. On the list for my next visit to the shop. Not sure of the price, but can't be much though.
BTW...a re-tune will be in order after changing your pulley and installing a restrictor plate.
BTW...a re-tune will be in order after changing your pulley and installing a restrictor plate.
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Thread Starter
Burning Brakes
Joined: Aug 2008
Posts: 906
Likes: 2
From: The Woodlands TX
Intermediate
Joined: Oct 2008
Posts: 32
Likes: 0
i cut a piece of alluminum the same size as the inlet tube that the air filter attaches to. i welded some tabs and bent them so they keep the restrictor secure in the inlet tube. i first cut a 3/4" hole in the center of the restrictor. i then made a run noting where the boost was. i then opened up the hole an 1/8" and did another run. on my setup an 1/8" equals around 1 psi of boost. it took about 8 runs to get it dialed in. you start with small increments. i got my stock bottomed ls3 with a 3.7" pulley restricted to 8.5 psi. it also has a 10% overdrive crank, which makes it equivalent to a 3.4" pulley. i also got carteks flipdrive installed. this is with a procharger d1sc
Last edited by duff70; Mar 17, 2009 at 11:03 PM.
Melting Slicks
Joined: Sep 2004
Posts: 3,153
Likes: 114
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Chris.
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From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
Simply put, a restrictor plate limits the maximum boost a given head unit can flow/generate/produce. Restrictor plates allow a user to employ a smaller pulley, thereby generating a greater level of boost (flow of air) in low and mid RPM ranges, and still limit the maximum flow of air/boost (in an effort to prevent a motor from experiencing an elevated level of boost which a motor may not be able to safely handle at higher RPMs).
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
For example, let's say I have a Procharger D-1 head unit with a 4.10" pulley with a maximum boost level of 8 psi at 6,500 RPM. Let's assume that in this example that at 3,000 RPM I am generating 3.5 pounds of boost and 250 RWHP and 300 RWTQ. Let's also assume that I want to have better low end performance (greater low end TQ and HP). The solution to my problem is to get a smaller pulley, say a 3.8" pulley, which may generate 5 lbs of boost at 3,000 RPM instead of the 3.5 lbs associated with the larger 4.1" pulley, and as a result increase my HP from 250 to 300 at 3,000 RPM, and increase of my TQ from 300 to 350 at the same 3,000 RPM level.
But let's also assume that I have a stock bottom end, and the smaller pulley will generate too much boost at higher RPMs than I am willing to run (due to the level of reduced safety associated with higher levels of boost at higher RPMs). Let's assume that the smaller pulley will generate 11 lbs of boost at 6,500 RPM, and that is too much boost for my stock bottom end. The solution to my problem is that I can then install a restrictor plate and limit the maximum boost at higher RPMs to a level I feel is safe, let's say 10 lbs, while still generating increased boost (and therefore HP and TQ) at lower/mid RPMs levels.
Bottom line is that a restrictor plate allows for higher boost levels via a smaller pulley, and therefore higher HP and TQ levels, in low and mid RPM levels, without having to contend with too much boost at higher RPM levels (by limiting the maximum flow of the head unit).
It's kind of like having your cake and eating it too. Because, when you get right down to it, what the hell good is a piece of cake unless you get to eat is as well. Cake may be fun to look at, but it's a whole lot more fun to eat it than just to look at it. Maximum HP and TQ at higher RPMs is great, but having a higher HP and TQ profile at low/moderate RPMs, as well as at higher RPMs, offers better overall performance/enjoyment.
Spot on, nice write up.
We came up with this set up when I was disappointed by the lack of torque compared to the turbo cars, we have tons of hours testing with our SC kit so when we send one out with the kit they are right where they need to be boost wise to achieve nearly the same TQ as HP.
This way, as you stated, you can have your cake (the simplicity of a centrifugal SC) while eating it too (the TQ of a turbo car without the expense and complications).
We have no problem explaining how to make one yourself, they are relatively basic, but there is some trial and error to get it right as far as the sizing goes. Fortunately it is all figured out for you when you purchase your supercharger from ECS!
We sell them for $24 separately Tony, but when not used with an ECS kit we cannot guarantee the accuracy of the boost levels.
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C5/C6 and C7 Supercharging Specialist
ECS Supercharger Kits / Mantic Clutches
www.EastCoastSupercharging.com
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C5/C6 and C7 Supercharging Specialist
ECS Supercharger Kits / Mantic Clutches
www.EastCoastSupercharging.com
Facebook Page
ECS YouTube Channel
Le Mans Master
Joined: Sep 2001
Posts: 8,840
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From: State of Confusion.
Here's a picture of one installed:
Some have tabs and some are just press fit into the grooves on the filter (as pictured) and then held in by the tubing/inlet. At least that's my understanding of it.
Some have tabs and some are just press fit into the grooves on the filter (as pictured) and then held in by the tubing/inlet. At least that's my understanding of it.
