Project: 1939 Jaguar SS100 Replica Classic Roadsters, LTD. "Duke"

[Bruce Nunnally]

One way to go to a turbo setup on the 3TC is to get an appropriate carb

Read more: http://www.jegs.com/p/Demon-Carburetion/Demon-Carburetion-Mighty-Demon-Blow-Thru-Carburetors/2849647/10002/-1

Available in 650, 750, and 850 cfm, Mighty Demon Blow-Thru Carburetors operate with up to 18 psi of boost. They increase the vacuum signal to the carb under boost to enrich calibration. Metering blocks have .078" power valve channel restrictors (others have .059"), and fuel bowls have solid nitrophyl floats and .130" needle-and-seat valves (.110" is standard).

Would need a custom intake manifold to bolt up the carb, then pipe in air after the intercooler, and tune.

[thedukejag]

Holy crap Bruce. Even with a Turbocharger,that is one huge carb.An 850 cfm carb is a lot for a big block street engine.Perhaps your research shows that this is a doable endeavor ,but I'm real skeptical. I would love to see where this is going ,though.

[Texas Jim]

I ran a 780 cfm on a high winding 340 cubic inch MOPAR, way back in the day and it was slightly too big.

[Bruce Nunnally]

I was thinking the 650 cfm, but depends on how many PSI of boost I suppose. The smart way is to do EFI (fuel injection) then a turbo, but we'll see. If the car stays carbed, it wants a carb built for boost like a holley marine carb, or this one I linked. There is a lot more fab and expense in getting the turbo setup though, which is what makes me think a tuned crate engine is an inviting solution.

I sent off to BRD Racing for more details but they really want to sort it out over the phone instead, so I guess I'll wait and see if I'm sure I want to write a check for a crate engine then call.

(See previous discussion here).

[Cadillac Jim]

I had a friend with a 350 hp 327 cid Corvette and he thought that the secondaries on his 850 cm Holley weren't opening. I drove the car myself and they didn't open in reasonable driving of someone else's car. I ran some calculations and figured that they secondaries *might* open near redline at full throttle.

The air flow rate is the displacement, divided by the number of strokes (four), times the RPM, times the "volumetric efficiency" (breathing efficiency) which is about 0.8 for a high performance street engine, higher for turbocharged or supercharged engines. There are units to convert, and you should have some margin to keep the vacuum very low at full throttle and redline for maximum horsepower, but these numbers surprise some people. For example, a 5 liter engine at 6000 RPM needs 212 cubic feet of air per minute, with a volumetric efficiency of 80%.

For more interesting numbers, put in the gas mixture of, say 12:1 and the energy of combustion of gasoline of, say 120,000 BTU/lb, then use a good high efficiency of 20% and this motor can theoretically put out 625 hp with that 212 cfm of air. Anybody have better numbers for mixture under full throttle and combustion energy of pump gas?

[Bruce Nunnally]

One of the HAMB guys previously found this on the BDS site,

It said :" To measure CFM on a blown engine: {(CID x RPM) ÷ 3456} x {Boost ÷ 14.7 + 1 } = Cfm "

So ((108 x 6500) / 3456 ) x ( 21 psi / 14.7 +1 ) = 203 x 2.8 = 567 cfm

Yes that is a lot of boost and yes that is what people run on these (and yes, dogs can live underwater, just not for very long).

I think I would prefer a strong revving normally aspirated engine (and seems simpler to me) but not ruling turbo out just yet

[Martin Monaco]

I would suggest beefing up the chassis and also the rear end first if you are serious about ever bumping up the power of the engine too much. The Duke chassis is too thin and flimsy and you'll end up ripping the car apart. :-)

[Bruce Nunnally]

Yes, but the original SS100 perhaps made 125 bhp back in the day, and weighed similar with a arguably much worse suspension (ok for its day). This was a sports car (for 1936), not 'just' a cruiser!

I also look at power rating with some deratiing in mind - shoot for more than target so if it runs under still over target.

Some Duke owners put 302 V8s in, so there is reason to believe more power suits.

But yes, good to keep the whole platform in perspective.

[thedukejag]

The evil twin that lives inside me keeps saying these cars are just screaming for a 302 roller motor and 5 speed,but as cyberfooks points out,oh yeah bigger rear axle,8.8 minimum,oh yeah reinforce the the rails.now it might need a cage.Upgrade wheels and tires..It never ends.Just saying....Rick

[thedukejag]

Getting back to the Turbo business.A four cylinder with fuel injection and turbo would have good street manners as it would not be in boost mode at normal driving conditions.The aftermarket fuel injection market makes this a very doable option.Would be a lot of fun. Rick

[Bruce Nunnally]

You guys are making sense and I am listening. I do want to give mine a bit more edge than current; we'll see how that plays out.

[Martin Monaco]

Please don't get the impression that I'm against it... I used to run a Nitrous Jag with 450 ponies on full boost and found out the hard way, which parts of the chassis and drivetrain, I should have beefed up. ;-)

The Duke chassis is one of the least sturdy which I have ever seen and it wouldn't be hard to custom fabricate a new chassis, which the Duke body could mount onto, which would be sturdy enough to handle whatever you could shoehorn under the grp. ;-)

[thedukejag]

So,are you thinking a 2x3 mild steel street rod type chassis.I think that would work very well.The mustang ll front end is already there and a bigger rear end would be easy. Rick

[Martin Monaco]

Rick,

Spot on sir! :-)

[Cadillac Jim]

I saw a retro-looking street rod around here (South Jersey near Philly) that had a nice look. As it turned a corner, I got a look at the exposed rear suspension and there it was, the unmistakable transverse leaf spring and SLA independent rear suspension of a Corvette. Of course I couldn't tell what generation. Apparently this guy got a Corvette that was totalled because of body damage and just put a street rod body on it. Lord knows what he did for the drive train.

But, a Duke body wouldn't fit over that chassis at all. Except for wheelbase, the dimensions encompassing the wheels and drive train are just not there. Perhaps a 1954 Chevrolet Bel Aire? Henry J?

[Bruce Nunnally]

The Excalibur automobile from Milwaukee, Wisconsin, was a car styled after the 1928 Mercedes-Benz SSK by Brooks Stevens for Studebaker. Stevens subsequently formed a company to manufacture and market the cars, which were conventional under their styling.

A prototype premiered at car shows in 1964, fitted on a Studebaker chassis and using a 290-horsepower Studebaker 289 V-8. Studebaker subsequently ceased its operations, ending the availability of its 289 V-8. General Motors friends Ed Cole and "Bunkie" Knudsen agreed to provide Brooks Stevens with Chevrolet 327s in 300-bhp Corvette tune, making the 2100-pound Excalibur a strong performer. With the standard 3.31:1 rear axle, acceleration from 0-60 mph took less than five seconds. Projected top speed was 160 mph.

The Excaliburs used Corvette chassis's

[thedukejag]

That would be a fun car and pretty cool looking also.A coup;e new pics.

[Cadillac Jim]

The Excalibur was around for quite a while. There were some driving around L.A. when we moved away for awhile in 1992.

That new picture of the Dutchess draws you in. There is nothing like a natural light photograph to bring out soul.

[Texas Jim]

The Excalibur automobile from Milwaukee, Wisconsin, was a car styled after the 1928 Mercedes-Benz SSK by Brooks Stevens for Studebaker. Stevens subsequently formed a company to manufacture and market the cars, which were conventional under their styling.

A prototype premiered at car shows in 1964, fitted on a Studebaker chassis and using a 290-horsepower Studebaker 289 V-8. Studebaker subsequently ceased its operations, ending the availability of its 289 V-8. General Motors friends Ed Cole and "Bunkie" Knudsen agreed to provide Brooks Stevens with Chevrolet 327s in 300-bhp Corvette tune, making the 2100-pound Excalibur a strong performer. With the standard 3.31:1 rear axle, acceleration from 0-60 mph took less than five seconds. Projected top speed was 160 mph.

The Excaliburs used Corvette chassis's

I ALMOST bought one of those in 1967...

I thought they were pretty... and with the Chevy running gear, they would be reliable.

[Bruce Nunnally]

Yes. The early Series had Chevy 300s, then 327s and 454s. Weight was 2400 lbs or so, and 0-60 was quoted in the low 5s at a time when few cars could touch that. Later they became more baroque and ornamental and lost the performance edge the designer intended. There is still some aftermarket parts support for these, and as you say with the Chevrolet engines would be easy to hodrod if desired.

There were Roadsters, meaning a 2 seat car for this marque, and phaetons meaning a 4-seater. I find the later cars less attractive, but an early, lighter, more powerful example from Milwaukee with a manual transmission is attractive. That said, I am not sure I wouldn't rather have the same-year Corvette. Lots more parts support for the vette.

I first saw an Excalibur in person as a teenager parked in front of a movie theater, and instantly fell in love with the look. They have always been more than I wanted to pay to own one however.

[Cadillac Jim]

I think that they are fibbing about the weight, though. The Corvette weight is usually about 3200 pounds curb weight (coolant, oil, half tank of gas, brake fluid and power steering fluid, ready to drive), more if it has A/C or big-block motor, the 36.5 gallon fuel tank, or some other options. Stripped for racing gets a stock-looking Vette to 2900 pounds without straining. But the Vette is hard-core engineered to control weight, and the Excaliburs were not, and they began with a corvette chassis, not something for the Studebaker 289. But 3000 pounds will still get you 0-60 mph times in the five second range.

[Bruce Nunnally]

Some chance my Duke Roadster will see sunlight this week, fingers crossed:

...struggled getting the differential to spring pads... So i ordered some industrial rubber and we are going to make them ourselves... we should finish up by the end of the week.

[Bruce Nunnally]

Here was the rest of my reply:

Hopefully it comes together well. The passenger footwell has the rear shocks and the front suspension a-arm strut bushings.

Besides the rear bushing issue and resultant effect on car dynamics the other reason I got into the suspension was to restore ground

clearance, which replacing front springs did.

I wonder if when the current toyota 3tc engine went in it mounted lower than the ford engine would have. I can't add headers to it

as it sits either because the collector hangs below the framerail and kills ground clearance (but added 5 hp).

Problem is we can't address wheel to fender gap by lowering (again) because only has 5" ground clearance to start with. If we go larger wheels then will have to regear speedo.

Counter to good handling, but can the engine be mounted 2-3" higher and not upset drivetain dynamics? Then headers can fit, and can lower Front springs to bring the fenders down.

Thoughts or advice?

[Cadillac Jim]

Handling dynamics are set in a chassis design by determining the roll axis and suspension compliance and damping. If the car's center of gravity is above the roll axis, the car will lean, but if the roll axis is too high and very near the car's center of gravity, the compliance of the suspension in cornering is very low and the ride and grip are not satisfactory for a street car.

Other axes are important, such as the pitch axis. Using the front suspension to raise the pitch axis to reduce dive on braking is anti-dive, and reduces front suspension compliance on braking, which can reduce braking traction on rough surfaces.

The roll axis passes through roll centers for the front and rear suspensions, which are set by the design and linkage. A live axle will have the roll axis pass through the center of the axle; a multi-link will place the roll axis higher and reduce lean. The front suspension likewise sets the front roll center.

Compliance and dynamics at the wheels is not as simple as one might think. Give and rebound in the tires, unsprung weight (wheel, wheel hub, and 1/3 of the suspension) and how it is distributed, the spring and the shock absorber all provide a complex transfer of each pavement irregularity to the chassis and a complex trajectory of the wheel hub, and the direction of the force on the tire and the suspension geometry interact to throw more variables into the equation.

The combination of factors being what it is, you may improve or degrade some handling features while degrading or improving others by raising the engine an inch or two. You won't know until you drive the car, and all the variables would have to be measured with a test track and instrumentation.

If it makes the car easier to work with and drive, raise the engine a couple of inches.

[thedukejag]

I also thought that there was too much gap between the top of the tire and fender.Simple,or so I thought,Just put blocks in the rear between the spring and pad.For the front, use drop spindles.When I looked under the car,there is very little clearance between the driveshaft and emergency brake bracket.One solution would be to raise the entire driveshaft tunnel,and for me that's not happening.So, I think to raise your engine ,you would need to raise the trans a like amount and unless your car is different you are up in the tunnel too much.The only viable solution I have seen is to use 18 or 19 inch wheels and tires as was used back in the 30's and 40's.They give the car a more period correct look,but as you pointed out,we now have speedometer issues.Probably the only way to use a header is modify what you have or have one custom made.I'm going back through this thread to review the header posts.