Powerband manipulation
Powerband manipulation
(OP)
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?
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?





RE: Powerband manipulation
Rod
RE: Powerband manipulation
In my world of 4-cylinder motorcycle engines with an even firing pattern, it's not unusual to have the intake runners a different length on the inner pair of cylinders compared to the outer pair, and it's rather normal to have the exhaust primary pipes join 1-2 and 3-4 (uneven pattern of pulses, 180 - 540 - 180 - 540 into the first junction). On some carbureted engines, the inner two cylinders are jetted differently from the outer two, and on fuel injected engines, they are often mapped individually to each cylinder. From that point of view, your idea is not completely out to lunch ... but on a V8, the exhaust is already asymmetric, so there is nothing extra needed to achieve that ...
RE: Powerband manipulation
RE: Powerband manipulation
I was making the design around the idea of using sequential fuel injection and individual coils. I was also hoping to run boost one day so I was going for a design that uses a plenum. I also want it to be a compact design like the LS1 intake manifolds.
RE: Powerband manipulation
RE: Powerband manipulation
RE: Powerband manipulation
We could call VW, as their new GTI certainly has its max torque from 1800 to 6000.
I can vouch for that.
Fe
RE: Powerband manipulation
I would have thought the drawback with using different tuned lengths and even different cam profiles in different cylinders would be the need to control the fueling and ignition separately to match. While this is possible to do, it certainly isn't particularly simple or cheap and there are easier and cheaper ways to go - like forced induction.
Nick
RE: Powerband manipulation
Indeed, my Kent SP 310 and SP 296 camshafts ARE ground with differing profiles. That's what the SP stands for "scatter pattern". It arranges different timing events for the center and the end cylinders of my Mini Cooper's race engine.
My first post was, admittedly, factitious. However, seriously, have a few more beers and perhaps you can come up with some other "off the wall" ideas. They are a hoot!
Rod
RE: Powerband manipulation
Come on 2 Hp from 2.1cc .
Sure you would have to pay 200 dollars every 15min for fuel....but who cares
Fe
RE: Powerband manipulation
Regards
Pat
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RE: Powerband manipulation
RE: Powerband manipulation
The only real way to spread the torque etc. is with a genuine variable duration cam - and, for all practical purposes, such things do not exist.
I agree with 540Z - even extremely odd ideas should be investigated - you can never tell where they may lead.
RE: Powerband manipulation
Something of the like of the camshaft had a '3D" profile manipulated by moving it along its axial direction.
Fe
RE: Powerband manipulation
As to the rest of it, VVT, VCR and, even variable valve lift have been used in the past. One odd design utilized a four valve design that opened the "second" valve as rpm increased. Not sure where that one went, it was in the 1920's or 30's. One newer version of that scheme was to use two seperate intake manifold runners for each intake valve. Hmmmm? Wasn't that the Yamaha deal at Ford?
Tmoose's link to the BBC/Lola manifold from the CanAm era was cool. One thing for sure, when you got passed by one of the CanAm cars using that configuration, it sounded like music to the ears. It was also awfully loud. BTDT!
Stay with it, guys. Sooner or later something will "stick"!
Watched a video of a F1 engine test run...Don't know what technology was involved to get a powerband of over 10,000 rpm. Sure looked/sounded good, though. I could almost "SEE" the $$$$$$ coming out the exhaust...
Rod
RE: Powerband manipulation
The "3D" cam is an often-suggested idea for variable duration but there are apparently real problems with the geometry of the tilting follower that is needed.
Ferrari did a lot of work with 3D cams but I don't think they were ever in a production Ferrari.
RE: Powerband manipulation
Good to know.
Fe
RE: Powerband manipulation
There's nothing to stop you from doing this- and the exhaust tract could be designed to do this also in league.
I would use 1 D cycle simulation to investigate.
This is what I will do for my Mopar engine and a Jaguar XJR (should I ever get around to buying one).
www.auto-scape.com
RE: Powerband manipulation
Thats the truest statement Ive read In a long while.
RE: Powerband manipulation
Regards
Pat
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RE: Powerband manipulation
RE: Powerband manipulation
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.
RE: Powerband manipulation
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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RE: Powerband manipulation
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
RE: Powerband manipulation
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
RE: Powerband manipulation
RE: Powerband manipulation
www.auto-scape.com