[DeTomaso] supercharger questions

[boyd casey]

Mike,
Once again in the interest of keeping my post brief i have condensed my
message. I know I have habit of being long winded and I am trying to improve
on that trait. I'm sure  engines will not suffer any dramatic reduction in
their life expectancy just because their bore or stroke have been increased.
Normally there is allot more that is done  to maximize the engines power.
The combined effect of pushing all of these systems to limits well beyond
their original engineers and designers intention weaken some parts of the
engine  to the point where they are at a dramatically increase the chances
of a failure. Now if these modified engines were driven in a "normal manner"
by normal manner I mean non -competitive operation, not racing, not pushing
the RPM's in excess of the original design specifications. In other words
driving it like a passenger car. Another factor when comparing a Ford (or
any other make stroker engine to something like an LS7 or LS9 or one of the
super charged  Ford Modular engines . Is That in the case of either the Ford
or Gm engines they have been designed and tested so that every component has
been selected and tested to provide the maximum output with out compromising
the engines efficiency or longevity. These engines are being sold in
production vehicles and are sold with warranties for up to 3 years and
36,000 miles.  They are expected to be driven hard and still withstand the
demands and stresses with out premature failure. Now when comparing to a
stroker motor there is no" standard" to compare too. Many stroker motors are
assembled by engineers that know and have researched the build to make sure
every component has been selected to match the other changes being made to
the engine. On the other end of the spectrum you get some backyard grease
monkey  who uses what ever parts are on hand and throws a stroker motor
together and has an engine that is full of "Weak links" and doesn't produce
the horse power gains expected.  Now when you take  either of these examples
of building a stroker motor and then operating it at levels that push the
limits of it's "weak links" the likely hood of a failure has a much higher
degree of probability. The Ls7  is over built using titanium pistons, push
rods, connecting rods and valves. It has every single component designed and
chosen just for this specific application. It has a 6 bolt main and rather
than being set up to squeeze out every last ounce of horse power it has been
designed to  to provide very substantial  power but not pushing it anywhere
near it's limits. The same goes for the LS9. Instead of throwing a
supercharger on to an LS7 block they went to the LS3 block to get the
thicker cylinder walls so it would be capable of withstanding the added
stresses of supercharging. They also  set it up to use only 5 or 6 psi. They
could obtain 700, 800, or 900 hp very easily by just increasing the boost
with a larger pulley. Because of the large numbers of engines produced and
their obligation to provide a warranty and a degree of reliability as well
as fuel economy ( stated EPA 28 MPG) . So in an effort to clarify my idea it
is that in a case where there is very little consistency in the various
stroker engines that people talk about while a GM factory built LS7 or LS9
is mass produced with as close to identical as you can get when comparing
one to another.  You can have a realistic expectation  to use your
engine for the purpose it was designed for. High performance, high speed
driving for extended periods of time with a realistic expectation that your
engine is going to last. With a Stroker built by either a recognised  engine
builder using a standardised set of components ( like Smeding performance )
they build a 427 stroker Called their 427 Cobra) based on a  a Windsor
racing block  , made by Dart. ( here's a link :
http://www.smedingperformance.com/ford/427+Cobra+Special+560+Horsepower.html
) It has an out put of 560 HP and 560 ft lbs of torque with a normally
aspirated 4 barrel carb. The block is around 140 lbs lighter then the
original block. . Smeding is a great company. All their engines come with a
dyno sheet from the  engine you actually buy ( not one "just like it ") and
the engine comes with a 24 month unlimited mileage warranty. All this for
$9995.00

 *Smeding 427 Cobra Special Features *

Block: Dart Splayed Cab Four Bolt Mains, C.N.C Machined, 4.125 Bore,
Scalloped Water Jackets, One Piece Rear Main Seal
Crankshaft: 4340 Steel, Non-Twist Forging, Micro Polished, and Chamfered,
Internal Balance, 4.000” Stroke
Rods: 4340 Steel "H" Beam with 7/16" ARP Cap Bolts, 6.200" Length
Pistons: LightWeight Forged, Reverse Dome, 10.2 Compression, with Wrist Pin
Below Oil Ring
Rings: Low Friction Single Moly 1/16” x 1/16” x 3/16”
Camshaft: Custom Ground Hydraulic Roller .544”/.573” lift 238°/248° Duration
@.050”
Rocker Arms: 1.6 Ratio, Full Roller To Reduce Friction
Intake: Edelbrock Victor Jr.
Cylinder Heads: Smeding / AFR, 205cc Intake port, Fully C.N.C Ported,
2.08"/1.60" Valves
Carburetor: Quick Fuel 750, Dual Feed, Double Pumper,Calibrated and Tuned on
our Dyno.
Distributor: Hall Effect Electronic, Polished Billet Aluminum Housing

Now I will grant that when you are dealing with an outfit that has a engine
like this that is thought out from begining to end and has a consistency of
manufacture and the manufacturer has the confidence to back up their product
with a 24 month unlimited warranty  it  shines a new light on the picture.

The only thing that still keeps the LS7 in contention for me  are the things
like the titanium gut,s the coil on plug ignition, the dry sump, thee EFI
and heads designed especially for this application. We all know a good EFI
system allows for an engine that will run more efficiently at any and all
weather and altitude conditions and is the reason this engine can crank out
505 HP while still providing an EPA est of 28 mpg.  In any case it is a
hypothetical exercise ( at least for me at this point). I need to finish my
Brembo brakes and the rest of my works in progress before I consider
tackling an engine change (plus my engine still seems to be running strong.
I have always been a believer in the adage if it ain't broke , don't fix it!

Boyd