Powerband manipulation 2

[540ZCar]

I want to build a Ford 302 with a redline of 6750 that has peak power at 6000. I rather have a broad powerband instead of high numbers so I want to fabricate intake and exhausts with different diameters and lengths for different cylinders.

Right now I'm thinking of setting up cylinders 1,4,6, and 7 tuned to peak power at 6000. Then cylinders 7 and 4 tuned for peak power at 5250. Cylinders 3 and 5 for peak power at 6750.
Then I was thinking that maybe it would be better to have cylinders 3 and 5 set up for 6750, 2 and 8 for 5250, 4 and 7 for 5750, and finally 1 and 6 for 6250 might be a better idea.

Which one do you feel will be the better route, and while I'm at it are there any formulas that you all know that will calculate what length and diameter would be ideal?

 

[patprimmer]

Tiger Woods and Jesse James might disagree on the grounds that they have both had some bad ideas recently. ;-)

Regards
Pat
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[LionelHutz]

I think you can safely assume it's a bad idea unless the it's required by the engine configuration. The only examples that have been given were done to make up for shortcomings in the engine.

 

[1gibson]

Sorry for no link, but I have seen an adjustable ratio rocker gimmick for OHV engines.

Big tilting cam mechanism mounted somewhere on the pedistal, controlled by an actuator that can increase lift at low RPM to increase power, then reduce at high RPM so your springs and heads don't have issues.

Not sure how effective, practical, or non-gimmicky it really is.

 

[patprimmer]

Sounds VERY gimmicky to me.

Good springs would be cheaper, easier, more reliable and a lot less bulky that what I imagine is involved.

Regards
Pat
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[dicer]

evelrod, you beat me to it, old tech stuff.
Hmmm kinda like when turbocharging and after cooling hit and everyone thought it was new stuff. It just took years to discover what was done in the old days. Something about modern engineering and regression. LOL

 

[anyoldname]

"The Porsche Cayenne V8 has a patent where by the cylinder that is effected most adversely by charge robbing, has an individual shorter profile to compensate."

Marquis, I'd be interested in understanding this, can you give me a few clues as to what this patent is on or how it works? Google has failed me so far.

Cheers, AJ

 

[BrianGar]

They learned Pat did'nt they, from their 'ideas'

 

[Marquis]

AJ- all I can reveal is exactly what I wrote- the cam profile on the adversely effected cylinder (adversely effected by charge robbing) has been individually optimised so that this charge robbing doesn't effect it so much. Charge robbing typically occurs on high output cruciform crank V8 due to charge robbing from an adjacently fired cylinder -typically during the overlap/scavenge period.

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