Proposal: Change in P Class Displacement

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3rdgendennis
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Proposal: Change in P Class Displacement

Post by 3rdgendennis »

This is just an idea I'm throwing out there to see if there is any objection, furthur justification, etc. I will make a formal proposal later.

Quoted from current rules:
PREPARED 2 – Cars with a displacement of 2201cc to 4500cc.
A. Supercharging, turbocharging, or nitrous oxide induction: Multiply actual
displacement by 2.

I would say, and hope others agree that a turbo 4 cylinder should not be run against a 500 hp modified, however by the current rules, a 2.5L Turbo Dodge, or an SRT-4 for example, would be pushed into P1. 2400 cc x 2 for turbo= 4800 cc = P1.

I propose to extend the Prepared 2 class to 5000 cc displacement

Another possibility would be to decrease the multiplier for a turbo to, say 1.5 or 1.75

Quoted from rules:
F. Four Wheel Drive: Multiply actual displacement by 1.25.

I believe (correct me if i'm wrong) that having 4WD or AWD would be much more desirable than a turbocharger on our hills (ask Joey Kale if he would rather give up his turbo or his AWD), however the turbo receives a bigger multiplier. I would propose to change that.

Any comments, objections, or justifications are appreciated.
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walterclark
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Re: Proposal: Change in P Class Displacement

Post by walterclark »

It took me about 2 minutes to locate turbo kits for a range of 4 bangers that claim to deliver 200hp or more per liter. This is an example for the Subaru but there are many other makes offered at this site with similar gains including you SRT4:http://www.turbo-kits.com/08+_wrx_turbo_kits.html

Around or a bit over 100hp per liter still seems to the about the reliable limit for a normally aspirated engine unless it is built to spin above 7,000 RPM or tuned to a narrow high RPM power band.

So a 2X factor for turbos still seems appropriate to me.

However, the idea of bumping the break point for P1/P2 up to around 5 liters has merit in my mind. A 5 liter break would put up to a 302CI NA engine in P2 where it would be in P1 currently as well as permitting 2.4 and engines like the Subaru 2.5 (2.46 liters). That would then leave "big" small blocks and big blocks in P1. Maybe make it a bit over 5000 so the old small blocks like 307, 318 and perhaps the 327 pushrod engines also fit in P2?.
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Re: Proposal: Change in P Class Displacement

Post by jkale »

Hmmm, hate to disagree with you but im gonna have to. Turbo 4 cylinders are capable of producing a lot of power..I mean 2.5L turbo AWD cars are kindof taking over the hills... arent they?

Maybe, include in your rule something along the lines of turbo size.... Like anything with compressor exducer larger than 70mm get a 2 for multiplier, anything smaller gets a 1.75 for a multiplier. Thatll put all "larger" turbo cars in P1 while "stock" sized turbo cars remain in P2.
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sachilles
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Re: Proposal: Change in P Class Displacement

Post by sachilles »

Just a thought, what about a multiplier for non stock engine management(perhaps different ones for N/A versus forced induction)? As anyone with an aftermarket turbo/supercharger would likely need, some sort of engine management solution. Yet those that have a turbo'd car that is stock relative to it's turbo, would be on stock management.

My thought on it is that for anyone to take advantage of big turbo upgrades, or adding a turbo to an N/A car, they'd really need aftermarket engine management to get the full amount of power out of the vehicle.

Not sure if this would work as intended, but maybe something like this would work.
Lower turbo's multiplier from 30% to 25%, and supercharger from 25% to 20%, and then ad a multiplier for non-stock engine management for 5%. Non stock engine management being defined, as any piggyback, stand alone, or retune of the stock engine management system.

Given a stock car, changing the engine management often yields good results. So it might be something due for a multiplier on it's own.

Just a random thought.
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walterclark
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Re: Proposal: Change in P Class Displacement

Post by walterclark »

I think to keep it from getting too complicated, the P class rules need to assume an engine type is developed to its max potential (or to any level the owner sees fit). I think that by trying to classify turbos by size or engine management mods within Prepared to determine class would make the class determination too complex.
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sachilles
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Re: Proposal: Change in P Class Displacement

Post by sachilles »

I see your point. I was thinking more along the lines of SP.

In regards to the srt4 in P, and displacement, I think the biggest obstacle might be the drivetrain orientation. I think higher horsepower front drivers have always had difficulty putting power down. I think if you had equal weight, and power and all other factors being equal, with the only difference being fwd vs rwd I think rwd would have a clear edge in a P prepared car.
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jkale
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Re: Proposal: Change in P Class Displacement

Post by jkale »

sachilles wrote:My thought on it is that for anyone to take advantage of big turbo upgrades, or adding a turbo to an N/A car, they'd really need aftermarket engine management to get the full amount of power out of the vehicle.

Just a random thought.
Seth, this is not true. It IS possible to tune the stock ecu to suit a large turbo.
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sachilles
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Re: Proposal: Change in P Class Displacement

Post by sachilles »

jkale wrote:
sachilles wrote:My thought on it is that for anyone to take advantage of big turbo upgrades, or adding a turbo to an N/A car, they'd really need aftermarket engine management to get the full amount of power out of the vehicle.

Just a random thought.
Seth, this is not true. It IS possible to tune the stock ecu to suit a large turbo.
I think you misunderstood, or I wrote it wrong.(or I still don't understand).

You can still use the stock ecu, but you must re-flash it. In essence changing the programming, making it non stock. I'm suggesting a reflash would be considered the same as an aftermarket ecu, or piggy back type of system.
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sdwarf36
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Re: Proposal: Change in P Class Displacement

Post by sdwarf36 »

You can still use the stock ecu, but you must re-flash it. In essence changing the programming, making it non stock. I'm suggesting a reflash would be considered the same as an aftermarket ecu, or piggy back type of system.
That has been discussed in the past-no way for tech to check it. Or if they could, it would easily be changed the second you made it past tech.
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sachilles
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Re: Proposal: Change in P Class Displacement

Post by sachilles »

True, you can't verify it easily. Lots of things can be changed after tech.

I was under the impression that NEHA operated more on the honor system. Do we ever tear down a car to make sure someone hasn't done something funny?
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