[DeTomaso] supercharger questions

Mon Jan 4 13:37:39 EST 2010

Ken , I agree with you and if you do the math a calculate the piston speed
for a stroker motor that exceeds 600 rpm  you will find that you are pushing
the documented limits of piston speed. there is a great book you can get at
Amazon.com called :"Auto math"
It contains all the basic calculations , equations, and theroy for an
automotive entusiast to calculate what type ofhorsepoer , torgue and RPM you
can obtain from an engine design and what type of effect certain
modifications will have instead of just guessing..
You will find that engines designed with very high operating RMPs have a
very short stroke. Infact if you want to build an engine to operate at a
very high RPM you would need to de-stroke it not stroke it. 5760 ft per
minute is around the maximum piston speed one can expect to operate at
unless you have built an engine with extremely high tolerances and very
expensive parts. The formula for piston speed is  piston speed in Feet per
minute = stroke in inches x RPM / 6, RPM = piston speed in FPM x 6 /stroke
in inches. When you put a pencil to your prospective engine design you will
find that with an increase in stroke you quickly reduce the RPM potential.
The Fodr 302 which was one of the highest reving ford engines commercially
available to the general public the stroke was   only 3.0 "  so at 8000 rpm
you had a piston speed of 4000 ft per minute,  a 351 with a stroke of 3.5 "
at 8000 rpm would have a piston speed of 4666 ft per minute.  A 351 with a
1/2 " increase to the stroke distance ( making it a 427)  would increase the
piston speed to 5333 fpm. It is much harder to build an engine that will
hold together under these types of stresses then it is to  build one that
will endure the higher pressure but lower revs of a super charged or turbo
charged engine. Remember that's also one of the reasons you need an engine
with much lower compression ratio if you plan to go with forced induction. I
highly recommend this book. It is availible in paper back. The author is
John Lawlor and if I remember correctly it only cost me a few bucks. Check
out Amazon. They have allot of books on engine design, supercharging and
turbo charging, Suspension and Chassis design, exhaust design. If you want a
crash course in the science behind making your car do what you want it to do
and you don't want to waste money  starting your own Research and
development lab this is the way to go.
Boyd

On Mon, Jan 4, 2010 at 12:22 PM, Ken Green <kenn_green at yahoo.com> wrote:

> As for as "why supercharging"  my answer is simple.  I had planned to build
> an engine using a Fontana block, Yates heads, and EFI.  I had repeatedly
> heard how the EFI calmed down the engine.  Then I was given a ride in a 500+
> HP Pantera, with an IR EFI, which people had said was a smooth running car
> due to the EFI.  I guess it's all subjective, but my idea of smooth is a
> whole lot smoother than the car I rode in.
>
> The solution was simple, either turbo charging or super charging.  40 years
> ago I was fine with a radial motor, but I also drove few miles, and never on
> a weekend getaway.  Now I want power and a car I can drive to Monterey for
> the weekend.  So it's a no brainer.  The only solution is turbocharging or
> supercharging.  Getting an extra 200 HP is nice also.
>
> Also, there is a power range where you must either supercharge or go to
> seriously high RPM to make the target HP.  I suspect it's cheaper to build a
> 600 HP turbocharged motor that redlines at 6,000 than a 600 HP normally
> aspirated motor that has to rev to 7,500 to make the same HP.
>
> Ken
>
> --- On *Sun, 1/3/10, boyd casey <boyd411 at gmail.com>* wrote:
>
>
> From: boyd casey <boyd411 at gmail.com>
> Subject: Re: [DeTomaso] supercharger questions
> To: "Ken Green" <kenn_green at yahoo.com>
> Cc: jderyke at aol.com, detomaso at realbig.com
> Date: Sunday, January 3, 2010, 5:27 PM
>
> Ken,
> I have spoken to Chris about his modular engine. I actually would prefer
> the
> Ford modular engine . I think the 4 vales per cylinder and the DOHC seem
> much more appropriate for an Italian exotic. The only problem is the engine
> costs around twice as much as an LS 3 getting more horsepower or an LS7
> with
> the titanium  guts and no forced induction getting 505 HP and 28 mpg. You
> can buy an LS7 for $13k and change.
> Hugh
>
> On Sun, Jan 3, 2010 at 7:47 PM, Ken Green <kenn_green at yahoo.com<http://us.mc308.mail.yahoo.com/mc/compose?to=kenn_green@yahoo.com>>
> wrote:
>
> > Boyd,
> >
> >     The ZF may be a bigger issue than the engine, and more expensive to
> > replace.  It may be good to not go above 800 HP?
> >
> >     I talked to Jim Bell (Kenne Belll Superchargers) a while back and he
> > said they get an easy 800 HP in one of the current  Mustangs (I think the
> > GT500???)  and it's a very reliable street engine.  He thought it would
> work
> > well in a Pantera.  Jim seems to have some pretty cool technology in his
> > twin screw superchargers and he seems to have a lot of real world
> > experience.
> >
> >    Chris Difani would have thoughts on this.
> >
> > Ken
> >
> > --- On *Sun, 1/3/10, boyd casey <boyd411 at gmail.com<http://us.mc308.mail.yahoo.com/mc/compose?to=boyd411@gmail.com>>*
> wrote:
> >
> >
> > From: boyd casey <boyd411 at gmail.com<http://us.mc308.mail.yahoo.com/mc/compose?to=boyd411@gmail.com>
> >
> > Subject: Re: [DeTomaso] supercharger questions
> > To: jderyke at aol.com<http://us.mc308.mail.yahoo.com/mc/compose?to=jderyke@aol.com>
> > Cc: detomaso at realbig.com<http://us.mc308.mail.yahoo.com/mc/compose?to=detomaso@realbig.com>
> > Date: Sunday, January 3, 2010, 3:25 PM
> >
> > Thanks for your quick and informative reply. I should have mentioned I am
> > not planning on supercharging my 37 year old Cleveland. I have been
> > thinking
> > about what I would  do ( or will do  when my Cleveland gives up the
> fight.
> > I
> > have no indication that this is an impending issue but one never knows.
> > It's
> > like a stroke or a Heart attack, if you knew it was coming you would
> > probably have done something differently. I know supercharging my old
> > Cleveland in any form would make the possibility of a major failure a
> > certainty instead of a possibility. I know many will think it sacrilege
> but
> > I have been researching  a supercharged LS3. Based on my calculations I
> can
> > get an engine with much more horsepower and almost all the technological
> > advantageous of the LS7 or LS9
> > including the efi specifically designed for the application and the coil
> on
> > cylinder ignition as well as the advantageous of the 6 bolt main ,
> aluminum
> > block and keep the price around that of the LS7 with 200 or more
> horsepower
> > then the LS7  . According to the horsepower estimates the LS3  376/480
> with
> > 6 psi would generate  675hp at the flywheel and 540 Hp at the rear
> wheels.
> > With 8 psi you would be looking at  756 hp and 605 hp at the rear wheels.
> > With a Whipple twin screw supercharger and 3 core intercooler you can
> > obtain
> > 25 psi . If you are prepared to push the envelope and the idea of
> > rebuilding
> > your engine on a regular basis does not bother you 20 lbs psi would
> produce
> > an estimated 1015 hp at the flywheel and 812HP at the rear wheels. You
> can
> > buy an LS 376/480 for $6399 directly from a GM dealer (the retail price
> is
> > $9138). The LS7 retails around $19,000 and you can buy one for around
> > $13,000 and the LS9 which is already supercharged , comes with a dry sump
> > and drive by wire controls will run you around $19,000. In all of these
> > examples you still need to buy an ecu and harness and with the LS3 you
> > would
> > need to spend between $6000 and $7000 for a complete supercharger setup
> > with
> > intercooler. You would also need a new bell housing with any LS based
> > engine
> > and as you know and with any engine that provides a big increase in
> > horsepower you  will need to regear your ZF if you wanted to convert all
> > the
> > extra horse power into a higher top speed and a quicker 0-60 ( like 0-60
> in
> > 3 secs in first gear). I like to think about the various re powering
> > possibilities during the winter months while I can't drive the Pantera.
> > When
> > the day comes that I have to take action I will be prepared to make a
> > decision having already done the research. I have been spending my time
> and
> > money upgrading my brakes and suspension. I want to make sure I can stop
> > faster before I worry about  going faster!.
> > Boyd
> >
> > On Sun, Jan 3, 2010 at 3:29 PM, <jderyke at aol.com<http://us.mc308.mail.yahoo.com/mc/compose?to=jderyke@aol.com>
> <http://us.mc308.mail.yahoo.com/mc/compose?to=jderyke@aol.com>>
> > wrote:
> >
> > > In a message dated 1/3/10 9:57:57 AM, boyd411 at gmail.com<http://us.mc308.mail.yahoo.com/mc/compose?to=boyd411@gmail.com>
> <http://us.mc308.mail.yahoo.com/mc/compose?to=boyd411@gmail.com>writes:
>
> > >
> > > Do you think a Whipple twin screw supercharger with an intercooler is a
> > > better choice or a Centrifugal supercharger ( like a Paxton or a
> Vortech
> > )
> > >
> > > Depends on the engine and what you plan to do with it. First, I would
> NOT
> > > supercharge any 351-C that's been overbored unless you have a
> sonic-test
> > in
> > > hand that shows over 0.100" cylinder wall thickness everywhere AFTER
> such
> > > boring. Thin walls flex with combustion pressures, blown engine
> > combustion
> > > pressures are significantly higher and cast iron doesn't flex very
> long.
> > So
> > > I'd suggest a different engine. Second, actually driving most blowers
> in
> > a
> > > Pantera is difficult due to not enough space for a proper width drive
> > belt,
> > > unless the engine is shifted backward. Shift the engine first before
> > buying
> > > any blower. Next, most blower kits are made for drag racing and don't
> > work
> > > well for long-haul use. Depends on your plans for the car. Budget about
> > > $7000 for such a kit and have an extra block or two around;
> blower-savvy
> > > engine bulders say your experience with superchargers is in direct
> > > proportion to the number of ruined blocks out back...All it takes is
> one
> > > (1.0) backfire to take out most systems so a really good ignition and
> > fuel
> > > system is much more important than higher boost. There's a reason most
> > > factory systems only push about 5-8 psi. Finally, whipplechargers are
> > well
> > > known for pushing more air more efficiently than other designs, without
> > the
> > > lag built into centrifugal blowers. A well-designed intercooler (few
> > really
> > > are, by the way) is worth a few more psi in boost at the cost of extra
> > wt,
> > > complication in mounting in a Pantera and $$$, plus more damage if the
> > > engine pops. You can't practically run an air-cooled intercooler with
> > most
> > > mid-engined configurations so a watercooled assembly makes more sense.
> > Good
> > > luck- J DeRyke (who owns two factory-blown vehicles- one intercooled.
> Fun
> > > for mountain driving.)
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