RJC powerplate theory at high rpm?

slimtastic

yea dude...I rock
Joined
Aug 9, 2002
i understand the basic operation of the RJC powerplate which is to restrict air flow from packing the back 2 cylinders and even out airflow properly across all 6 cylinders to prevent a lean condition in the back and a rich condition up front.

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but looking at this thing, i can help but wonder if my engine is getting full boost at the back of the valve, full boost like what my gauge(tapped in front of the plate) is getting? then i wonder if the restriction in route to the heads gets even worse at 5500? 6000? 6500 rpm?

this is in no way bashing RJC or their products AT ALL. i run a powerplate on my car and will for every turbo buick i own. but i am asking if its a great idea to have all vacume/boost references for wastegate/map sensor before the plate or after the plate??

i mean if the plate starts to restrict more at higher rpm wouldnt you be loosing psi to the motor and therefore leaving hp on the table at the top end

any thoughts on the subject?
 
yea but you can compress air,not a liquid

and that same air is gonna act differently at 3500 rpm than say, 6500 rpm will the powerplate restrict cylinder filling near redline?
 
yea but you can compress air,not a liquid

and that same air is gonna act differently at 3500 rpm than say, 6500 rpm will the powerplate restrict cylinder filling near redline?

It still doesn't matter. Pressure is distributed equally.

And HP is really about airflow not boost pressure
 
It still doesn't matter. Pressure is distributed equally.

And HP is really about airflow not boost pressure

how do we know the same ammount of pressure is distributed past the plate? airflow is hp i agree, but doesnt a restriction in the path of airflow hurt the hp possible?all things being equal isnt there more potental "airflow" in 15lbs vs. 10lbs?

what if lets say 19 lbs of boost in a high loaded gear starts to taper off closer to redline cause of a restriction induced by a powerplate? what if it tapers off to 18 or 17 lbs? if it does then thats power left on the table.
 
how do we know the same ammount of pressure is distributed past the plate? airflow is hp i agree, but doesnt a restriction in the path of airflow hurt the hp possible?all things being equal isnt there more potental "airflow" in 15lbs vs. 10lbs?

what if lets say 19 lbs of boost in a high loaded gear starts to taper off closer to redline cause of a restriction induced by a powerplate? what if it tapers off to 18 or 17 lbs? if it does then thats power left on the table.

Under 6000rpm on a 231ci you will not flow more air through the engine than the plate itself can flow. The pressure of the intake charge has nothing to do with the flow. There could be 300psi and zero flow if all the valves were closed.
 
Under 6000rpm on a 231ci you will not flow more air through the engine than the plate itself can flow.
even with a heavy set of heads and a cam to match?
The pressure of the intake charge has nothing to do with the flow. There could be 300psi and zero flow if all the valves were closed.
i get what your saying but i was talking about all things being equal on a running motor from the standpoint of air temp/headflow/backpressure ect.... if you turn the pressure up in the manifold then the potental airflow through the heads/valves goes up
 
if you turn the pressure up in the manifold then the potental airflow through the heads/valves goes up

The mass flow goes up not the cfm. Airflow has to do with the movement of the air the air through the engine not the density of it. The overlap period and backpressure has a very small effect. Heads and cam will increase the engine rpm potential and increse cfmh. You wont have a hyd cammed engine making peak power over 6000 rpm.
 
Here is the simple answer:
If you add up the area in sq mm of the RJC power plates holes they will be larger to or equal to that of the throttle body.
The throttle body is the dictating restriction factor; so if you were to get a hogged out throttle body and upper plenum then perhaps the RJC power plate would become a restriction.
 
With and without RJC Power Plate, racing/mpg results, Thumbs UP WITH

After speaking to Red Armstrong, regarding Ron Joseph, with his car around 700 HP with rjc powerplate, after removing rjc powerplate (restrictor plate) over 800 HP... on the dyno....

I Drove my 87 Buick GN with over 100,000 miles from Auburn Maine to Bowling Green, KY USING RJC POWER PLATE
MPG 16.58 mpg up to 20.71 mpg using 91 octane, 93 octane in states available, now apply to my street driven vehicle
ok NO it is not 0-60 in 2 seconds,

but now I have numbers to back it up
Kumho Estac AST 245/50/16 Street Tires
RJC POWER PLATE, weight of car 3745 pounds

13 Gallons of 93 octane plus 4 gallons of 110 octane, then adding 2.5 gallons of 110 total for fuel, to begin racing on Thursday Oct 21, 2010... and no fuel changes for friday with very strong head wind....

20 Quarter Mile Passes from 11 am to 5 pm --- best runs at the end of day
ALWAYS DRIVEN IN OVERDRIVE, when I try "DRIVE" I get high rpm and spins out, I gotta get out of the hole and going and my black stallion loves to fly, maybe becuz I have TA 49 turbo with GN1 front mount intercooler, after the tube is filled up watch out, pulling hard with right fuel... add 110 or higher, boost up 24 pounds, no knock...

There were some other tweaks, but cant give away all the secrets, haha

Sunny Beautiful Day - No Wind
2:13 pm - Oct 21, 2010 - Thursday
R/T: .109
60': 1.814
330: 5.128
1/8: 7.90
MPH: 88.88

1000: 10.303
1/4: 12.483
MPH: 97.94

Oh yeah, this pass I removed my freaking floor mat to get more throttle,

2:17 pm - Oct 21, 2010
R/T: .641
60': 1.806
330: 5.136
1/8: 7.920
MPH: 88.53
1000: 10.334
1/4: 12.396
MPH: 108.95


Back to conversation after racing, discussing power plate, and we know the benefits, and my car runs great either way when adjusted, however after drinking at hotel, we Removed power plate

HERE ARE RESULTS WITH NO RJC POWER PLATE AND VERY STRONG HEAD WIND
Those who had boost to turn up had a great day, but those maxed out on the best day felt the wind the next day pushing slower numbers...
Friday Oct 22, 2010
7 Quarter Mile Passes from 10:40 am - 4:47 pm
10:54 am - Oct 22, 2010
R/T: .655
60': 1.998
330: 5.362
1/8: 8.15
MPH: 88.13
1000: 10.584
1/4: 12.651
MPH: 108.76

3:00 pm - Oct 22, 2010
R/T: .693
60': 1.951
330: 5.272
1/8: 8.039
MPH: 88.90
1000: 10.446
1/4: 12.503
MPH: 109.14

4:47 pm - Oct 22, 2010
R/T: .860
60': 2.077
330: 5.463
1/8: 8.251
MPH: 88.65
1000: 10.656
1/4: 12.702
MPH: 109.87

The only way is to test back to back on and off with power plate for cars under 600 HP or 500 or over 800, I dont know what HP is applicable

BUT based on my results I firmly believe for my application
USE RJC POWER PLATE
My scanmaster numbers love the way the RJC Power Plate Massages the air in and how it runs best... maybe your car is best...
using my signature parts... and HRPARTSNSTUFF REAR SUSPENSION, use of C116 fuel, I see low 12's and more tweaking high 11's next year

After Bowling Green, I drove 87 GN from Bowling Green, KY to Kaukauna, WI
616 miles 18.82 mpg - 20.94 mpg, ranging in speeds that moves with traffic, ok with my GN - I love to lead and leave the bad drivers weaving in and out behind me... now I have new max speed on my GPS....

My 87 GN loves bolt on parts with pure 93 octane...
go to the track add racing fuel turn the boost up, 20 mpg,
mid to low 12's 110 mph, depends on weather and fuel...

Oct 24, 2010 No RJC Power Plate, Fuel Tank Filled up with 93 octane
Boost turned down 16-18, down the track in overdrive

9:16 AM- Oct 24, 2010
R/T: .313
60': 2.196
330: 5.725
1/8: 8.623
MPH: 84.92
1000: 11.127
1/4: 13.246
MPH: 106.10

Overall, my car is STOCK with bolt on parts with LIL TA 49 Turbo and a BIG FRONT MOUNT INTERCOOLER
USING FULL HR Parts n Stuff Rear Suspension... 1.806 with street tires and using RJC Power Plate....

interesting topic of conversation GS Nationals 2010....

Next year = HIGHER OCTANE plus Drag Radials....
 
Drill and tap the lower intake and install another boost guage then you will know for sure. Easy enough to prove or diprove the theory.
 
Here is the simple answer:
If you add up the area in sq mm of the RJC power plates holes they will be larger to or equal to that of the throttle body.
The throttle body is the dictating restriction factor; so if you were to get a hogged out throttle body and upper plenum then perhaps the RJC power plate would become a restriction.

i know what your getting at, but what about the idea that high speed air hates making turns? or backing up? or hitting the back wall of a dog house and having no choice but to backfeed towards the throttle then down through a powerplate? wouldnt that cost cfm? wouldnt that be an artificial restriction causing a loss of power?


My scanmaster numbers love the way the RJC Power Plate Massages the air in and how it runs best...

well yea but lets say that you fully setup your car around the idea of "no power plate" by this i mean adjustable fuel and spark per cylinder and egt probes for each runner inthe exhaust.

then via egt probes you managed to trim individual cylinder corrections to have the same egt(basicly the same AFR). would the power plate still make the same power? assuming both setups were ran to the same afr obviously....


Drill and tap the lower intake and install another boost guage then you will know for sure. Easy enough to prove or diprove the theory.

thats basicly what i was gonna end up doing. kinda wondered if anyone had ever checked
 
well yea but lets say that you fully setup your car around the idea of "no power plate" by this i mean adjustable fuel and spark per cylinder and egt probes for each runner inthe exhaust.

then via egt probes you managed to trim individual cylinder corrections to have the same egt(basicly the same AFR). would the power plate still make the same power? assuming both setups were ran to the same afr obviously....

your thinking to much :p Melissa's GN street car .. 9.9@ 138+ drive in ..race..drive home. NEVER broke a plug or blown a headgasket. Tuned with a scanmaster for NO KNOCK :cool: Have the PP on all my junk here. If ya do a search this has been beaten to death :redface:
 
your thinking to much :p :
i get that alot
Melissa's GN street car .. 9.9@ 138+ drive in ..race..drive home. NEVER broke a plug or blown a headgasket. Tuned with a scanmaster for NO KNOCK :cool: Have the PP on all my junk here. If ya do a search this has been beaten to death :redface:

i was just wondering if 15 lbs on the top of a powerplate would be 15 lbs on the bottom of a powerplate. no worrys its just somthing i was thinking about
 
hey slim,
if you do end up adding that seccond gauge, im sure there are plenty of people here that would like to know the outcome if you would like to share.

nice thought, keep em coming.
 
hey slim,
if you do end up adding that seccond gauge, im sure there are plenty of people here that would like to know the outcome if you would like to share.

nice thought, keep em coming.

sure thing. whenever i get some raw data ill post up
 
i know what your getting at, but what about the idea that high speed air hates making turns? or backing up? or hitting the back wall of a dog house and having no choice but to backfeed towards the throttle then down through a powerplate? wouldnt that cost cfm? wouldnt that be an artificial restriction causing a loss of power?

Air not wanting to turn is the reason for the power plate. The air doesn't want to turn to get to the front so the front cylinders get less air(richer) without the powerplate. The limiting factor is how lean the rear cylinders are. Say you are at 450 horsepower and the rear two cylinders are making 80 hp each, the middle two are making 75 each and the front two are making 70 hp each. Now say you add the powerplate and you restrict flow to the rear cylinders which drops you to 77hp there but because the front 4 cylinders are getting similar air flow as the rear cylinders you are now getting 75hp out of each of the front 4 cylinders so you end up with 454 horse power.



well yea but lets say that you fully setup your car around the idea of "no power plate" by this i mean adjustable fuel and spark per cylinder and egt probes for each runner inthe exhaust.

If you can do this with the more expensive software but not with the stock computer.

then via egt probes you managed to trim individual cylinder corrections to have the same egt(basicly the same AFR). would the power plate still make the same power? assuming both setups were ran to the same afr obviously....

the powerplate would make less power. But the engine would run smoother if you can equalize air flow to each cylinder and have each cylinder making the same power.

thats basicly what i was gonna end up doing. kinda wondered if anyone had ever checked


David
87gn
 
If you can do this with the more expensive software but not with the stock computer.

If you had cylinders that were known lean you could absolutely have a chip burner add fuel to those cylinder(s). Under 600hp you wont see much adjusting every cylinder. More of a reliability thing. Fwiw the cylinders that usually go lean when running hard with the factory fuel system are #1 and #3.
 
A few years ago I worked on a pro outlaw car that had a 540cid alchy/blower set up:rolleyes:.Under the helix blower was a triangle plate that was alot smaller than the blower opening.:confused:The reason was to equally distribute air.With mech fuel injection it would always pick on cylinders.:rolleyes:The blower would always ram all the air to the rear cyl and they would go lean.Same principle:biggrin:


Kevin
 
Slim,

Air under pressure does not even come close to behaving like N/A airflow.

Also to clear up the pressure issue: A system under pressure exerts pressure equally on each and every surface in the system... basically pressure is pressure, no matter what, when, where, or how.

Pressure is also not the concern here, mass air flow is.

I too work with 1,500hp blown methanol BBCs... we use airflow distribution plates.

Haha I'll second that you're thinking too much, F/I is a different kind of animal.
 
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