[DeTomaso] Weber's or IR Stack EFI for high HP applications
Daniel C Jones
daniel.c.jones2 at gmail.com
Sun Dec 7 19:45:31 EST 2014
> Dan thought that Weber's wouldn't supply enough fuel to reach the maximum
HP potential.
That's not exactly what Dan said. 48 mm diameter IDA Webers will supply
the fuel, they will just become restrictive on air flow at greather than
500 HP. 48 mm is approximately 1.89 inches. Your A3 cylinder heads have
intake valves that are 2.19" in diameter. Area goes up with the square of
diameter so there is no way the carbs are going to flow as well as the
cylinder head intake ports. Shelby ran 48 mm IDA Webers on the 289 Cobras
which used an intake valve approxiamtely the same size (1.875 inches in
diameter) as the Webers. For the 427 side oiler engines, Ford cast up a
special run of 58 mm (2.28 inches) Webers. Vizard's testing (on his 350
SBC pick up truck engine) indicated that a suitably sized single four
barrel carb made better power above 480 to 500 HP than 48 mm IDA Webers.
He ran the Webers because they made better average power (better low and
mid range power) and returned 18 MPG in the truck.
> When I approached Jim Inglese about a set of Webers he was adamant that
was complete BS, quoting numerous race cars running well north of 600HP
using 48IDA Weber carbs with no issues
And NASCAR uses 390 CFM Holley barrel carbs as restrictors in some of their
classes (Truck and Southwest Tour). With larger carbs, the engines would
make a bunch more power and those 390 carbs are seriously re-worked. My
engine builder's carb guy gets around $5000 for a Holley "390" CFM race
carb (which are legal to the specs but flow more like 600 CFM at 20.3
inches of water, the truck carbs have looser rules and flow more like 750
CFM).
The point is not will 48 mm IDA Webers support 600 HP, the point is how
much power do they give up on a 600 HP engine?
Dan Jones
On Sat, Dec 6, 2014 at 3:38 PM, Boyd Casey <boyd411 at gmail.com> wrote:
> I was asking Dan Jones aboutA running Weber's on the engine he and
> Dave McClain areA A putting together for me. Dave is building and Dan
> doing the simulation and design.A It's a 408 stroker A-3heads fully
> portedA (not back from the porter yet ) so they have not been bench
> flowed yet. I really like the looks and sound of a stack set up and
> since I am running 180 degree headers the sound with stacks the sound
> can't be beat.A Since my engine is expected to be producing north of
> 635 HP at 6500 rpm Dan thought that Weber's wouldn't supply enough fuel
> to reach the maximum HP potential. Does anyone have experience or
> opinions on a set up that wouldA allow for the optimum low , mid range
> and high endA HPA withoutA losing any throttle response or HP at any
> of the key points.
>
> A On another point who makes the best Chassis stabilization kit (
> rigidity kit) for use on a 1971 L.A I already have Billet rear risers
> , CV joints ( porsche 930) poly bushings from Dennis Quella ( along
> with his Koni set up and coil overs, Sphere ball end sway bars Front
> a-arms modified by johnny woods modified for maximum adjustable castor,
> Brembo 4 piston calipers from a Porsche 911 turbo, Coleman custom made
> rotors with center directional vanes and gas vents and custom billet
> hats. Dual CNC master cylinders with a balance bar long throw clutch
> master with SS sleeve andA Anodized Slave cylinder with SS sleeve. So
> I want to get the best possibleA Rigidity kit for the full chassis
> Front hood,rear engine compartment, under chassis. Also any other
> recommendation which could be made to help deal with the high
> horsepower and torque.
>
> _______________________________________________
>
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-------------- next part --------------
> Dan thought that Weber's wouldn't supply enough fuel to reach the
maximum HP potential.
That's not exactly what Dan said.A 48 mm diameter IDA Webers will
supply the fuel, they will just become restrictive on air flow at
greather than 500 HP.A 48 mm is approximately 1.89 inches.A Your A3
cylinder heads have intake valves that are 2.19" in diameter.A Area
goes up with the square of diameter so there is no way the carbs are
going to flow as well as the cylinder head intake ports.A Shelby ran
48 mm IDA Webers on the 289 Cobras which used an intake valve
approxiamtely the same size (1.875 inches in diameter) as the Webers.A
For the 427 side oiler engines, Ford cast up a special run of 58 mm
(2.28 inches) Webers.A Vizard's testing (on his 350 SBC pick up truck
engine) indicated that a suitably sized single four barrel carb made
better power above 480 to 500 HP than 48 mm IDA Webers.A He ran the
Webers because they made better average power (better low and mid range
power) and returned 18 MPG in the truck.
> When I approached Jim Inglese about a set of Webers he was adamant
that was complete BS, quoting numerous race cars running well north of
600HP using 48IDA Weber carbs with no issues
And NASCAR uses 390 CFM Holley barrel carbs as restrictors in some of
their classes (Truck and Southwest Tour).A With larger carbs, the
engines would make a bunch more power and those 390 carbs are seriously
re-worked.A My engine builder's carb guy gets around $5000 for a
Holley "390" CFM race carb (which are legal to the specs but flow more
like 600 CFM at 20.3 inches of water, the truck carbs have looser rules
and flow more like 750 CFM).A
The point is not will 48 mm IDA Webers support 600 HP, the point is how
much power do they give up on a 600 HP engine?
Dan Jones
On Sat, Dec 6, 2014 at 3:38 PM, Boyd Casey <[1]boyd411 at gmail.com>
wrote:
A A I was asking Dan Jones aboutAA running Weber's on the engine
he and
A A Dave McClain areA AA putting together for me. Dave is building
and Dan
A A doing the simulation and design.AA It's a 408 stroker A-3heads
fully
A A portedAA (not back from the porter yet ) so they have not been
bench
A A flowed yet. I really like the looks and sound of a stack set up
and
A A since I am running 180 degree headers the sound with stacks the
sound
A A can't be beat.AA Since my engine is expected to be producing
north of
A A 635 HP at 6500 rpm Dan thought that Weber's wouldn't supply
enough fuel
A A to reach the maximum HP potential. Does anyone have experience
or
A A opinions on a set up that wouldAA allow for the optimum low ,
mid range
A A and high endAA HPAA withoutAA losing any throttle response
or HP at any
A A of the key points.
A A A On another point who makes the best Chassis stabilization kit
(
A A rigidity kit) for use on a 1971 L.AA I already have Billet
rear risers
A A , CV joints ( porsche 930) poly bushings from Dennis Quella (
along
A A with his Koni set up and coil overs, Sphere ball end sway bars
Front
A A a-arms modified by johnny woods modified for maximum adjustable
castor,
A A Brembo 4 piston calipers from a Porsche 911 turbo, Coleman
custom made
A A rotors with center directional vanes and gas vents and custom
billet
A A hats. Dual CNC master cylinders with a balance bar long throw
clutch
A A master with SS sleeve andAA Anodized Slave cylinder with SS
sleeve. So
A A I want to get the best possibleAA Rigidity kit for the full
chassis
A A Front hood,rear engine compartment, under chassis. Also any
other
A A recommendation which could be made to help deal with the high
A A horsepower and torque.
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