"The 2.6 right now is 3.0 undercover."

Leadfoot said:
I agree.

I know LOTS of people hush this topic but what about the cheapest and easiest way to restrict air (restrictor plates). Hell, even NASCAR does it. They had problems trying to limit carbs and intakes (and guys spent money and got creative) and it was a tech nightmare (much like turbo restrictions), then they went with restrictor plates.

Why can't we do a similar thing. Restrictor tubes in the intake. A Tube (spec tube if need be), needs to be plumbed into the intake stream. It has to be X maximum ID, X minimum length (at that ID), and be placed X/Y distance from the turbo inlet with no other areas for air entry between it and the turbo and be sealed tight to the turbo inlet.

Simple, effective, easy to tech (with a pair of calipers) and it doesn't matter what turbo you run. Changing an intake system is a hell of a lot easier than changing a turbo. Also jumping classes would be easier (just have another section of intake to swap in/out). I'm willing to bet large chargers will have a hard time sucking through straws and will elimate large chargers in small classes........
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This could be a good thing in the 2.6 class to encourage the hot trucks to bump a class but I don't think it's a good idea beyond that. The bigger classes seem to regulate themselves fairly well.
 
I agree that 2.6 is the new 3.0. It's kind of silly to see $50,000 roller motors running in what was supposed to be an entry level class. Also odd to see a 3.0 truck pull 2.8 and 2.6 in one night. Heck, why not pull the weight rack off and run against some little farm kid in 2.5? I like the idea of measuring compressor housing diameter along with inducer size. Easy to enforce and seems like a way of keeping the "cheaters" out.
 
Your going to have a hard time restricting the turbocharger rule to the extent needed, I like the restrictor plate idea, but again many won't accept it.

S300 frame - 2.6" wheel must protrude MWE allowed
S400 frame - 2.6" wheel must protrude MWE prohibited

Could even take it one step farther and say no T6 turbine housings.
 
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I pull with the Midwest Pullers and we have a 9.5" max compressor housing rule which might keep some 3.0 chargers out, but I have a custom gt42r with protrusion on my truck and its just under the 9.5". We talked about lowering it to 9.0" but that would have eliminated an off the shelf S465 so we left it alone. Very tough if not impossible to get a turbo rule to get the 2.6 back to an entry level class.
 
I believe restrictor plates would work. They use them in LeMans style racing since the Audi and Peugot TDIs came in and started whipping everyone's asses.

Take the compressor map, draw a vertical line on the right hand side, and that's all the air you get....it literally chops off the flow at a pretty specific mass flow rate, irrespective of pressure ratio.

They do the same thing for the Formula SAE (engineering college car competition).

Usually it's a thin plate orifice at X diameter, Y thickness, Z distance from the comp wheel.

The reason it works is that the pressure drop across the orifice goes through the roof once the linear speed reaches certain values. With so much inlet depression, there is little one can do to try and recover it. The only thing from a tech perspective would be finding any and all "leaks" around the orifice....and again you would have the innovators at work...."really Gene, I have NO IDEA how that boot came off, I guess I didn't tighten the clamp enough, golly gee shucks" :blahblah1:

Nascar-style approach. On the one hand, people want that, on the other hand it just sounds too scary to reduce pulling to an actual driving competition :hehe:
 
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JQmile said:
I agree that 2.6 is the new 3.0. It's kind of silly to see $50,000 roller motors running in what was supposed to be an entry level class. Also odd to see a 3.0 truck pull 2.8 and 2.6 in one night. Heck, why not pull the weight rack off and run against some little farm kid in 2.5? I like the idea of measuring compressor housing diameter along with inducer size. Easy to enforce and seems like a way of keeping the "cheaters" out.
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Compressor housing diameter is a bit too simple...I can think of workarounds already....back to graduate level Fancy Covers ($$$) course...
 
nwpadmax said:
...."really Gene, I have NO IDEA how that boot came off, I guess I didn't tighten the clamp enough, golly gee shucks" :blahblah1:
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Top 3 trucks get teched after the event. Spray propane (or similar) around the turbo inlet and see what happens. Simple/easy/effective. If RPM's go up, you're DQ'd. It's a puller's responsibility to make sure his/her truck is pull ready. You might get away with it at one or two pulls, but it's bound to be caught. One bad pull (aka a DQ) and your shot for the title is gone.

nwpadmax said:
on the other hand it just sounds too scary to reduce pulling to an actual driving competition :hehe:
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:lolly: Yeah, we wouldn't want people to actually learn how to read dirt and drive a puller now would we.... :hehe:

The problem is it's simple, easy, effective, and would work. Something like that doesn't belong in truck pulling :pop:
 
LB7 heaven said:
Very tough if not impossible to get a turbo rule to get the 2.6 back to an entry level class.
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I hate to start this into *bdh*, but restrictor plates would.
It would also allow existing "fancy", "custom", "cheater" turbo's to run without having to buy a new one or modify. All the big companies could start mass producing "spec" restrictor plates for a minimal fee and cash in as well.

Power WILL go down, competition will get closer, driveline parts will be saved, overall cost will go down (initial purchase and repairing), and hopefully those that feel as though it's out of reach will take the plunge.

A spec would have to be determined with diameter, length, FINISH, etc. and restrict any extra machining, surface prep, coatings, etc, etc. Keep it plain and simple. Allow for NO modifications whatsoever (no gray areas), if you modify it in any way, shape, or form, you cheated. :rules:
 
Isn't a bushing the same thing as a restrictor plate? I don't see any difference. Maybe the distance from the turbo will have some effect but in the end who really cares. Just allow bushings. Bushings keep cost down, at some point you can only spin so big of wheels and it will be diminishing returns going bigger.
 
Just allow bushings. Bushings keep cost down, at some point you can only spin so big of wheels and it will be diminishing returns going bigger.
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Hang on to your ass the bad stuff is comming.
 
lubeowner said:
Isn't a bushing the same thing as a restrictor plate? I don't see any difference. Maybe the distance from the turbo will have some effect but in the end who really cares. Just allow bushings. Bushings keep cost down, at some point you can only spin so big of wheels and it will be diminishing returns going bigger.
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LOL You wish!
 
itpa uses a restrictor plate for there pro farm class seems to work. restrictor plates dont have a map groove.:charger:
 
lubeowner said:
Isn't a bushing the same thing as a restrictor plate? I don't see any difference. Maybe the distance from the turbo will have some effect but in the end who really cares. Just allow bushings. Bushings keep cost down, at some point you can only spin so big of wheels and it will be diminishing returns going bigger.
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A thin plate orifice will be more "lossy" and will be more effective at reducing HP than a bushing of the same ID. So for example I'm just throwing this out, a 2.5 bushing within 0.050" of the wheel may be equal to a 2.6 thin plate restrictor. So yeah, I think you could work out some equivalent diameters and put them in the same ballpark.

Also, as said above, the thin plate restrictor restricts the flow through the MWE as well....so it kills 2 birds with one stone, and keeps the MWE from being developed as an advantage.

I guess you could have bushings made that also block off the shroud and stop the flow through it. That's probably the cheapest solution and most effective.
 
is it me or is the overall wheel size the bottom line. thats what it all boils down to. pop the cover and check it or nobody knows what the hell is inside......
 
Is it too far out there to suggest looking at the truck, not just the charger?
Don't get me wrong, I like the charger rules that are trying to bring the 2.6 class to just that, 2.6. Could you say, no duals, maximum of 1000lbs hanging out front, the rest in the box to make 8000? Just thinking out loud.
 
Moore Power said:
Is it too far out there to suggest looking at the truck, not just the charger?
Don't get me wrong, I like the charger rules that are trying to bring the 2.6 class to just that, 2.6. Could you say, no duals, maximum of 1000lbs hanging out front, the rest in the box to make 8000? Just thinking out loud.
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The 1000lb rule might be tough to tech. Limit the tires and you will limit the useable power.
 
Probably a single 35x12.5 and maybe duals would have to be the factory size.
 
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