cotpc 2.5 question

Macktruckdriver

Macktruckdriver

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OK I'm working on a 2.5 truck for MTTP rules. I'd like to make it for our rules but also cotpc so I can make the run out of state when we don't have a hook and make it to some big hooks. Our rules don't say anything about no runner intakes so I was going to run a side draft intake. However Cotpc says no "individual runner intakes". So technically a side draft isn't an "individual" runner intake. So are they allowing side draft intakes or no? If no what are guys doing? Cutting the intake off and bolting on a "stock appearing" intake? I'd like to figure out what direction I'm going with the head.
 
Most I've seen are either a box or shelf replacement style... I guess I don't understand what your refeering to as a side draft.
 
I've been wondering about that similar question, is a side draft consider the same as bolting on an intake runner like what enterprise makes?
 
I think the "stock appearing engine" might make the side draft a no go. I just want a simple yes or no from them not the BS if I want to pull with them.
 
This style of intake is legal.
image-9.jpg


This style is NOT legal.
image-8.jpg
 
So is a side draft that's more like the enterprise one just air comes in differently. They need to just say one way or the other. Aftermarket/cut off intakes are legal or not. Not word it so retarded.
 
Macktruckdriver said:
So is a side draft that's more like the enterprise one just air comes in differently. They need to just say one way or the other. Aftermarket/cut off intakes are legal or not. Not word it so retarded.
Click to expand...

Not sure whats so hard to understand. It's pretty straight forward "NO INDIVIDUAL RUNNER INTAKE MANIFOLDS".





"The engine is limited to a stock appearing, OEM compression engine, available from the factory in a one ton or smaller truck. Cubic Inch limit of 444CI. Block must circulate coolant freely. No hard filled blocks. Water pumps may be factory or electric powered. All factory belt driven accessories, excluding the air conditioning compressor, must be retained and powered via the crankshaft by a standard serpentine “V” belt. Electric cooling fans are permitted. No individual runner intake manifolds. (Example: ZZ-customs). Belt driven alternator. No deck plates. "
 
So why word it that way? Are individual runners going to gain anything over a side draft? I don't see how they would.
 
How much do those run from them? Looks like a nice piece


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Maybe because they didn't want to allow individual runner intakes.:doh:

Yes they make more hp.
 
OK that's what I'm asking. At first I was only looking at it from the standpoint of porting the head more on the intake side. I didn't think individual runners would make any more power. How does that work? More velocity through the runners? If so that explains the intake I saw the other day that was like an individual runner intake but then welded closed to look like it didn't have runners.
 
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The runners should help with the velocity if built correct and the big plenum allows you to have a higher volume of air on hand and helps distribute it more evenly to each cylinder when it's needed. This might not be 100% correct but it's what I was told probably 15 years ago by a pretty good source.
 
Macktruckdriver said:
If so that explains the intake I saw the other day that was like an individual runner intake but then welded closed to look like it didn't have runners.
Click to expand...

And here's where the grey areas come in the rules...the rules say no individual runner intakes, but it says nothing about an intake that has been modified as you posted above.

So, would it pass tech if you did something like this, had the individual runners enclosed inside a plenum that appeared as a stock or side draft intake?

The rules say stock appearing, but also say no individual runners...this looks stock or at least close from the outside...
 
That's what I was thinking a side draft isn't "stock appearing" but it's not a individual runner either.
 
Machine a stock style plenum with runners built in. Then bolt on a plenum to the top. Problem solved. Ive have always been curious why the intake manifold rules are always directed at the cummins engines and nothing about duramax engines.
 
I love how it says no Hamilton for Cummins, no brodix for duramax...... In other words anyone dumb enough to run a power stroke have at you need all the help you can get we will look the other way.
 
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