Restrictor plates
07-07-2010, 12:06 AM
#1
Racer
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Restrictor plates
I know this request is unusual for this forum and is opposite what most people want to know but....
Does anybody have any data on the effect of restrictor plates on reducing horsepower/torque? My 89 turbo is basically stock with a fresh rebuild with Carillo rods and JE pistons, a 3" Lindsey exhaust and no cat with a Flowmaster race muffler, Lindsey clubgate, and factory mapped chip with the overboost raised. I dynoed at 238hp and 268 torque at the wheels. I'm looking for a way to reduce power to be legal for different race groups. I have a machinist that can make me a set of restrictor plates for between the throttle body and intake that we can swap out on the dyno to see the effects of different sizes and would like to know if anyone has tried this and what kind of diameter bores you used and what kind of reductions you saw. I need to keep all the wastegate plumbing stock. Any data supported info is appreciated...
Does anybody have any data on the effect of restrictor plates on reducing horsepower/torque? My 89 turbo is basically stock with a fresh rebuild with Carillo rods and JE pistons, a 3" Lindsey exhaust and no cat with a Flowmaster race muffler, Lindsey clubgate, and factory mapped chip with the overboost raised. I dynoed at 238hp and 268 torque at the wheels. I'm looking for a way to reduce power to be legal for different race groups. I have a machinist that can make me a set of restrictor plates for between the throttle body and intake that we can swap out on the dyno to see the effects of different sizes and would like to know if anyone has tried this and what kind of diameter bores you used and what kind of reductions you saw. I need to keep all the wastegate plumbing stock. Any data supported info is appreciated...
07-07-2010, 12:25 AM
#3
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It may not be as easy to change but a set of plates between the intake manifold and head would probably be a workable solution for you. If you do it at the throttle body you have to take into account accumulating pressure / volume under boost in the area past the plate before it reaches the cylinders which could be a tuning nightmare.
If you do make the plates between the manifold / head make sure to offset the restricted holes to the top in order to preserve the injector spray pattern. Sounds like a neat idea. Let us know how it works out with some dyno sheets if you do runs.
If you do make the plates between the manifold / head make sure to offset the restricted holes to the top in order to preserve the injector spray pattern. Sounds like a neat idea. Let us know how it works out with some dyno sheets if you do runs.
07-07-2010, 12:47 AM
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I would dyno every setting on the FQR first .
then consider a throttle stop.
and posibly even consider putting a restrictor on the inlet of the turbo sometimes it will bring the turbo into a more efficient part of the map so you may see a torque increase ..it is increases the pressure diferntail across the turbo without increasing manifold pressure ..and the turbo map is worked out in pressure differential across the turbo..
then consider a throttle stop.
and posibly even consider putting a restrictor on the inlet of the turbo sometimes it will bring the turbo into a more efficient part of the map so you may see a torque increase ..it is increases the pressure diferntail across the turbo without increasing manifold pressure ..and the turbo map is worked out in pressure differential across the turbo..
07-07-2010, 08:59 AM
#5
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Restrictor plates (unless really small) will not affect mid-range torque but might be usable to limit high RPM power. You would be much better off to regulate boost – that will give you an across the board adjustment for torque and HP.
BTW – you might have a problem with the throttle butterfly hitting the restrictor plate if you go with a simple plate behind the throttle body.
You could just stuff the air filter box with oil dirty laundry
BTW – you might have a problem with the throttle butterfly hitting the restrictor plate if you go with a simple plate behind the throttle body.
You could just stuff the air filter box with oil dirty laundry
07-07-2010, 09:16 AM
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Since you were hitting the Overboost Protection on the chip, I would start by lowering the boost to get the HP you want.
07-07-2010, 10:27 AM
#7
Nordschleife Master
I would dyno every setting on the FQR first .
then consider a throttle stop.
and posibly even consider putting a restrictor on the inlet of the turbo sometimes it will bring the turbo into a more efficient part of the map so you may see a torque increase ..it is increases the pressure diferntail across the turbo without increasing manifold pressure ..and the turbo map is worked out in pressure differential across the turbo..
then consider a throttle stop.
and posibly even consider putting a restrictor on the inlet of the turbo sometimes it will bring the turbo into a more efficient part of the map so you may see a torque increase ..it is increases the pressure diferntail across the turbo without increasing manifold pressure ..and the turbo map is worked out in pressure differential across the turbo..
2005, bmw, body, f250, ford, limit, muffler, plate, plates, restrictor, restrictors, throttle, torque, turbo, turbocharger, turbochargers
