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anybody run a centri blower with a wastegate???

6750 Views 21 Replies 9 Participants Last post by  Mach828
anyone here run a wastegate on there centri setup? kinda like a tq booster i've been thinking about doing this but not really sure if its worth it.. if you have can you post your results? thanks :beer:
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No but im planning too with a head unit upgrade. What blower? You'll want to pulley to the max impeller rpm your blower allows and belt can hold. and then run the wastegate. I don't think most people know how it works and they are confusing an internal vs external wastegate on a turbo vs a centri. You would need to have the external wastegate before the intercooler so its premaf. The one on the torque booster setups is a bit much because those are being used on novi 2200 head units which push way more air than your procharger p1. A smaller wastegate would be fine. Do it!
A restrictor plate is a rigged setup for those who can't afford a wastegate. It isn't going to provide consistent results in the same way as a wastegate. With a wastegate you will maintain a set boost all year long in any elevation, it bleeds off excess air to maintain a set absolute pressure. Its reliable. One of the biggest factors for air output is the input. You put something in front of the blower to make it more difficult to pull air in and you're disrupting the mechanics of the blower's efficiency. There is a reason the inlet has the diameter it does.

Lets say you spin it hard and its in the 70% efficiency range of the compressor map flowing xxxcfm. You add a wastegate it bleeds off the air after its already been "converted" and more or less maintains the efficiency (less heat more useable air flow). If you restrict the airflow before its used, you upset the design of the blower. Its spinning at the rate that should be 70% efficient but since you've made the inlet opening half its size, it is less efficient and generates more heat and less air used to add volume and pressure in the cylinders. Sure, spin it three times faster at half the efficiency and its going to still make more power, you're just cutting yourself short and ruining one of the best benefits of a IATs and high efficiency.
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Procharger does not offer compressor maps for their superchargers. I made an excel lbs/per min calculator a while back to help me pick the right turbo. OP here is my best guess for your 3.7 mapped on a Vortech SI trim compressor map, closest comparison I have to a P1. (90% ve, 100* iat, 10lbs of boost with a wastegate, 7,000 max rpm).

Due to the engine size, you really don't generate a lot of air flow but rather a higher rate of pressure build up. By capping the boost with a wastegate you'll flow more air without increasing pressure, allowing the supercharger to move closer to its efficiency range.

The restrictor plate on a larger v8 like the vettes works okay since they flow a lot more air with little boost build up, and is already in the more efficient range on the compressor map, so you can sacrifice a little efficiency and still manage to get some extra power. You do it on your car and you'll just ride the surge line.

For comparison here is my car on a v2 map. Each green dot is 1,000rpms, boost is progressive to 8lbs. Notice that the increased displacement allows more lbs/min with less boost, better matching the efficiency range of the blower.

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