Highest HP /6 ?
yes he has for sure, seen it like many others. you would think he would share his receipe!!! LOL
one thing about Mark's times... it does give a lot of credibility to the slant. not that i'm saying his power level was obtained thru any small $$$ ???????
Mark's green Lancer ('62?) is really fast for a naturally-aspirated slant six. The numbers that the online Wallace calculator give for his performance are as follows: 10.87 hauling 2,370 pounds (2,200 pounds, plus 170 pounds, driver weight,) require 364 horsepower, and the horsepower to go 119mph at that weight, requires 320hp... indicating that Mark is getting some help from the kinetic energy stored in a heavy flywheel spinning at a high rpm before the clutch is dumped for the launch. That utilized energy will show up on the e.t., but is momentary, so isn't very much in evidence on the mph. Hence the discrepancy in hp figures, from the e.t. to the mph.
If you're really interested in engine output, I'd say, go with the mph figures, since they're not skewed by the utilization of the stored energy in the spinning flywheel.
Even using the lower figures from the mph, (320) he scores an impressive 1.32 horsepower per cubic inch, NORMALLY ASPIRATED!
Given the asthmatic architecture of the slant six cylinder head, that is just amazing!!!! But, to achieve the Hellcat trouncing performance his car displays, he has taken about 400 pounds of ground-hugging weight out of that car. I say, more power to him!!!:cheers: There's more than one way to skin a (Hell) cat! AND, HE DID!!! :blob:
FABO memeber Mopar805kid built a streetable slant six that was naturally-aspirated, with maybe not ALL, but a LOT of bells and whistles, leaving very little on the table, and after months of tender love and care, could only manage about 99 mph out of his 3,000-pound '68 Dart, which is indicative of about 246 horsepower (@ 3,000-pounds plus 170 pound driver weight.)
Still, that is over 1 horsepower per cubic inch (1.1) out of a
street motor, with a strangulated cylinder head... not bad at all... Impressive, really!
The restrictive cylinder head is the Achilles Heel of any slant six motor, and there doesn't seem to be any way to fix what's wrong with it. The higher-ups mandated a short (lengthwise) motor when the Valiant was being designed, and the only way to get one (out of an inline six,) was to make the specs for the bore-center spacing "close," so they did, ending up with some very skinnny 3.4" bores. That left no room for decent size valves, and the engineers designed ports to match those smallish valves. The head really worked well on the 170 it was designed for, but when they modified it to get the 225, they stroked it a FULL INCH, for a 33-percent increase in size, they didn't do anything at all for the breathing; that's why it is so unresponsive to normal hot rod methodology for power increases.
The only thing that seems to bring it into the big leagues as far as power-output is concerned, is forced induction.
Getting 500 horsepower out of a 225 is readily available with a flat tappet cam, one four barrel carb (properly tuned, ) and a 5,500 rpm redline.
Two FABO members (Tom Wolfe and Ryan Patterson) have built engines that have posted numbers that are indicative of that power output, with Ryan's car, at 2800 pounds, sans driver, runnning 10.74, pulling a big 727 transmission, (@ 127 mph) and Tom's 400-pound heavier '70 Dart, running into a 15mph headwind, posting an equally-impressive, 11-flat at 120mph.
Here are the videos, for those of you who might have not seen them:
[ame="https://www.youtube.com/watch?v=7QzUfV8iTpQ"]Turbo Slant Six 10.74 @ 127 mph 7-19-10 - YouTube[/ame]
and
[ame="https://www.youtube.com/watch?v=EAxRmoDgsdY"]Turbo charged Slant 6 11.02 @ 120.56 - YouTube[/ame]
The amazingly strong, sturdy block and head permit boost levels in a slant six that would turn most other engines into a bucket of broken parts, making it the perfect candidate for turbocharging or supercharging.
But, if you're not looking to build a car that can do serious battle with 340s and 360-s...
There is a different plan for those among us who don't have unlimited funds to shell out for a motor: There are degrees of forced induction that will allow performance improvements on a smaller scale, that can use stock repiprocating components (pistons, rods, and stock, unaltered cylinder heads) that will yield 200-250 horsepower with little in the way of expenditure for forged internals, but the performancce gains are nothing like those demonstrated by Tom's and Ryan's cars.
Limiting boost to ten pounds and spark advance to 18 degrees and running premiusm pump gas will yield a `4-second slant six car, if you're careful with the tuning.
And yes, a 250 horsepower slant six can be pretty entertaining!
You pays your money and you takes your choice! :D