[gio_momma]

Originally Posted by Dick Monahan Just out of curiosity, how does one enforce this rule? I assume tell-tale tachs can be rigged?

It's pretty easy on a crank-triggered ignition, like an electromotive or MSD. Plug in a signal generator set to something just over the limit and if you have spark, you're busted.

http://www.electromotive-inc.com/pro...simulator.html

[spankytoo]

This is just going to start new R&D. A new cam profile for a different RPM range. It is not going to solve cost issues. My solutiion is this: Give everybody a three year notice that in the year 2013 ALL MOTOR RULES WILL RETURN TO THE YEAR 1991!
If you are an in block cam you are a CAST IRON BLOCK and 166 Cubic Inch!
If you are an over head cam block you are a CAST IRON BLOCK and 155 Cubic Inch.
Volkswagen style is 140 Cubic Inch.
Dual overhead cam is 122 Cubic Inch.

[AsianPersuasian]

I can see where USAC is trying to go with the concept of limiting RPMS. They comissioned Ilmor to perform dynamic analysis of the typical midget engine setups. This most likely included an analysis of modal performance (i.e. vibrations & harmonics) as well as strength/materials analysis given the engine operating at various RPMS. The numbers presented were probably the ranges with the best compromise of power vs. reliability. In other words, perhaps 8,700rpm for a pushrod engine hurts the HP/TQ, but yields gains in the modal performance department. Less vibration due to operating within an RPM range that does not contribute to harmonics would significantly increase the life of an engine. Apply the same concept to strength/materials of the engine components...you see where this is going.

Having said that, I like the eco-tech....bring it on.

[LEADERS EDGE]

Originally Posted by AsianPersuasian I can see where USAC is trying to go with the concept of limiting RPMS. They comissioned Ilmor to perform dynamic analysis of the typical midget engine setups. This most likely included an analysis of modal performance (i.e. vibrations & harmonics) as well as strength/materials analysis given the engine operating at various RPMS. The numbers presented were probably the ranges with the best compromise of power vs. reliability. In other words, perhaps 8,700rpm for a pushrod engine hurts the HP/TQ, but yields gains in the modal performance department. Less vibration due to operating within an RPM range that does not contribute to harmonics would significantly increase the life of an engine. Apply the same concept to strength/materials of the engine components...you see where this is going. Having said that, I like the eco-tech....bring it on.

Possible...Possible. You're right....they could have taken all of the motors, put sensors on them and gathered base information on the material properties used to assemble the individual componets.

They could have ran all of the motors on a spintron doing extensive RPM simulations based on the various tracks that are run. Using the base information; they could have then inspected the used parts verses the new parts and found an optimum operating range.

That....or they could have taken three people on staff....placed blindfolds on their faces with the names of the different motors.....and bobbed for apples with RPMS on them. Whatever they pulled out....was the RPM.

More than likely....the scenario was that they took RPM readings during the season and came up with what they felt the average was.

I doubt a sincere investigation into harmonics was performed. If it was....there may have been a case for higher RPMS. Thing about a dirt racecar...it's those things like corners and heavy clay and traction and things like that which makes motors do an extensive amount of grunt work.

Using a high RPM reading as basically a guide for making motors live longer is pretty short sided. Those numbers are often a "flash" number. A number that is just for a brief moment. It's not a sustained number except at somewhere like Pheonix or Belleville or the alike. These motors don't operate constantly at the 10,200 range or 9,200 range. They spend most of their lives in the 4,200 to 6,000 range. That isn't going to change.

[gio_momma]

The Esslinger motors have a few more inches because they are actually a production-based design. The ST (and EST now) uses lots of stock parts and dimensions. The CORR/TORC/Lucas Pro-lite guys run a very similar motor on gas with an iron block and they make similar power. The aluminum block is a weight and reliability thing.

Since they are, they have a smaller (much smaller) bore center than the "half a V8" designs. They can't run anywhere near the intake valve size ( or should I say utilize?) that a 4.something bore motor has room for. You can put a bigger one in a small bore, but the cylinder wall shrouds the port.

[Charles Nungester]

I still say the easiest rule and cheapest for racers to cut cost is to cut the tire size in half.

[polecar]

how is this going to work for people who still run a mag?

[jdull99]

We better be home free Randy!!!

Jason Dull
815 494 6002
jdull99@hotmail.com
jasondull.com (For all the Racing News)

[plum]

West coast won't follow it. power i is not going to. Usac won't be able to police it they never can. They can't even pump a motor in calif. So there going to do this for there 12 nat. cars. Or are doing it for toyota. I don't beleive they will have a western states midget series next year with ventura starting its own next year.

[TQ29m]

Originally Posted by Charles Nungester I still say the easiest rule and cheapest for racers to cut cost is to cut the tire size in half.

How about they make all the bleacher seats out of 2X4's on edge!