2015 RCR #2

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Al Fernandez
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2015 RCR #2

Postby Al Fernandez » Sat Sep 26, 2015 1:18 pm

Dyno Start RPM Revision
---1) Dustin Mozader, Rocky Mountain Region #45, Supercharged111@gmail.com/719-648-0594
---2) Rule reference: AI/CMC Dynamometer Inspection Procedures #10 -
Three consecutive runs shall be made under full power. The RPM range shall be consistent for all three runs. Starting RPM shall be no higher than 2000. Ending RPM shall be clearly beyond max horsepower.
---3) Recommended Revised Wording - Three consecutive runs shall be made under full power. The RPM range shall be consistent for all three runs. Starting RPM shall be no higher than 3000. Ending RPM shall be clearly beyond max horsepower.
---4) Reasoning for change MUST include at least 1 of the following:
---------->d) Will improve competition because…
Drivers of all platforms will be able to utilize their peak torque values. LT1s create an artificial torque peak around 2500 RPM when fitted with small restrictor plates. In contrast, less healthy LT1 engines fitted with larger or no restrictor plate will have their torque peak at 4000 RPM which is closer to where the LS1, 5.0, and 4.6 peak. Racing below 3000 RPM provides no competitive advantage no matter how much low end your motor has. Because of this, torque values below 3000 RPM are irrelevant and should not be factored in.
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Glenn
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Postby Glenn » Sat Sep 26, 2015 4:45 pm

Been saying this for years. It was more of a problem @ the 230hp years.
Texas Region AI/CMC Series Director
Inferior Driver, Superior Platform…. since 2005.

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Al Fernandez
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Postby Al Fernandez » Thu Oct 01, 2015 3:54 pm

Anyone have data to back this up?
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Supercharged111
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Postby Supercharged111 » Thu Oct 01, 2015 8:11 pm

Here's my first dyno from this year when the motor refused to break in on the dyno. You can clearly see the slight rise in torque at 4000 RPM thus indicating its peak. This dyno was run with no restrictor.

Image

And here is my current dyno with a 38mm restrictor plate. Note that by 4000 RPM torque is on its way down and the blue line clearly indicates a peak just before 2500.

Image

I won't personally benefit from this RCR as my peak torque is only 304 averaged among the 3 runs, but IMO it just makes sense.
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Glenn
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Re: 2015 RCR #2

Postby Glenn » Thu Oct 29, 2015 8:27 pm

I think peak HP/TQ numbers should only come from between 3500-5500 RPM's. Seems like a good starting point.

If my peak TQ is @ 2500 RPM's (and it is in that area) and I'm pulling out of a corner in a gear that has the RPM's down that low, I'm gonna get my ass handed to me.

I'm considering increasing the exhaust size to kill low end TQ. Either 3" duals or a 4" single. Space is an issue.
Texas Region AI/CMC Series Director

Inferior Driver, Superior Platform…. since 2005.


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