Twin Supercharged Hudson Hornet

TwinSupercharged

I have adapted, built and installed a twin supercharger setup on my Hornet 308. Induction is through twin cross over pipes to twin Rochester 2-jet carburetors, that have been sealed for blow through, and are mounted onto an Edmonds intake. The SC's are 1940 Graham, that have been modified to run in tandem, with all internals rebuilt. Power take off is supplied via 3 v-belts. No one in the Graham club or owners of supercharged Graham vehicles could say what boost a single SC would put out. I am happy to say that I get 4 pounds of boost at 4,000 RPM. My expectation was 3 to 5 pounds, 4 pounds is great!! If I would take it to 4,500 to 4,700 I would expect to obtain 5 pounds, but will not chance it.

This build took about 1 1/2 years at part time. I will show pictures and text in a couple of time buckets as I have a lot of data. Here is the finished product.









This is a factory print of a stock Graham SC setup. Note only one SC utilized with the carburetor mounted on top of SC. I elected to use blow thru carburetors with velocity stacks on top SC. My bug screens are Walmart SS tea strainers.


More Pixs and data to come. thanks

Beforemytime

Like.
It's purdee!
Thanks for posting

Ol racer

Very Nice Installation!

terraplane8

We look forward to seeing a video of this working hard!

foxsnout

..it looks fantastic! I wanna hear it running.

iceblade10

Wow! Amazing.

Jay_G

Great looking, I hope it runs a well as it looks.

Jay

TwinSupercharged

The Graham SC is a worm drive at 5:1 ratio, so 4000 at the crank with a 1:1 pulley equals 20,000 RPM at the rotor. Not high in todays 100,000 + RPM centrifugal SCs and turbos but good enough for 1940. There are two vertical and three horizontal Babbitt bearings that needed to be cast and bored along with re-grinding the shafts. My hot rod buds said to replace the Babbitt with roller and needle bearings but research showed that the Babbitt had a lower coefficient of friction than the roller or needle bearings. Babbitt has two weakness; low impact resistance and requires a constant flow of oil for the oil film bearing area. The Graham SC has no impact on its vertical or horizontal shafts, but relies on a constant oil feed from the engine's oil pumping system. I elected not to use the Hornet's oil system for lubricating the two SCs. The Hornet's oil pump ranges, with RPMs, from 0 to approx. 45 PIS with approx. 0 to 4 or 5 GPM. I felt that a constant PSI and GPM would insure a more continuous oil film bearing. I accomplished this with a separate 12V turbo scavenger oil pump drawing from and returning to the Hornet's oil pan. I also, gained on and off control of this pump allowing me to turn on the pump with no engine rotation at start-up and shut down for pre-oiling and/or cool down.


For all of my builds I utilize dimensioned drawings, transferred to cardboard, transferred to wood (if applicable), transferred to end metal.
I do not weld nor do I have a lathe or mill. But I am very fortunate to have three skilled friends working out of their garages only 15 minutes from home. One is a welder/fabricator, one has a Harding chucker lathe and a #2 Bridgeport mill and the other has a horizontal and cylindrical grinders, I am all set!


This shows wooden mounting brackets to the block and the individual SC angle mounting brackets, mocked up.




The wood mock ups transferred to metal. I used every tapped hole on the drivers side of the block.




The bolster plate is mounted with the rear SC in place



Here is the real first assy/pre- fit of the two SCs with all brackets.





Three pixs of the bench assy and setup with brackets and drive take off being developed.
This is where the bolster plate aligns the two SCs and the drive shafts. (Note: 1939 Stude street rod pix in corner)





Next three are of completed assy's, painted and plumbed for the external oil system. The white canister is the 12V turbo scavenger oil pump I utilized for this setup.

Note: all assy's are bolted and dowel pinned to accommodate removal and re-install all back in the same location and same alignment.







This all could not have been accomplished without relocating all of the accessory drive brackets (A/C, Alt., PS). Note the SC power take off pulley and shaft are fixed and all three belt adjustments was accomplished with each assessory's individual tensioning mechanism, no idler pulley.




Now the installation of the Edmonds' intake and the twin Rochester 2-jets.


Finished product with cross over pipes and velocity stakes. Note, the balance tube between the cross overs for equal boost to each carb. (4 pounds at 4,000 RPM)





Now the end ride. As you can see the body and paint is next, but first I have to go looking for some rice burners to nock off.






Thanks all, for looking. Fred

29sptphaeton

What did you use for a steering box for your power steering? Looks like a GM pump.

TwinSupercharged

yes a GM pump. The steering box is an after market Ford Mustang for early years. I got from ABS with opposite rotation. Mounted in the same location as the original box with a custom made mounting bracket, I fabricated.

TwinSupercharged

I forgot, I will post a video when I learn how to.

Glowplug

Fred that is a LOVE of the UNUSUAL result!!! Great pictures. Thanks for posting

Ol racer

Awsome Job of Engineering and Fabrication... Car will be a sensation at Cruise- In's…….Just a cooling tip from the Western Reserve Chapter over here in Pa, put a cup type soft plug (Dorman #565 023) in the Goose Neck recess at the top blocking the bi-pass then drill a small steam hole in the center of the plug; Then, Install a modern thermostat like Ford 390 V8 Gates #33036. I seal the t/stat into place in the goose neck before set on the head.

TwinSupercharged

Olracer, thanks for the comments. I used Walt's blockout and drilled thermostat assy. Runs very cool, thanks for the heads up on the Gates number.

PaulButler

Beautiful workmanship Fred! Keep the story going with pictures

pistonfarmer

amazing, do you have drawings for your mounting plates?

BigSky

That is such a blessing to not only have guys near you with those skills but to be able to have then do some unique things like you are doing is outstanding.  I’ve never been lucky enough to have any car guys even in my neighborhood!  

Thank you for sharing & I would love to see some video on it running as well!

TwinSupercharged

TO PISTONFARMER; I do not have drawings, I started with cardboard..but I do have the wood patterns, which I could trace onto paper if that is workable to you. Note: I believe you are only interested in the two brackets that mount to the engine block? They mount 1 inch off of the block. The front utilizes the two head bolts and two tapped holes originally for the generator. The back will only fit if you have changed the starter to a mini gear drive starter. E-mail me if you want the paper tracings. Fred

HOVBOY

Hi Fred awesome looking but no cooling by water or intercooler  any problems with preheated air? my intention is to fit a Graham unit on my 8 cyl Stude

MickeyB

Those superchargers can't be easy to get, nor cheap.  Tremendous amount of engineering there.

50C8DAN

Is that a straight 8 Stude or V8?  I can't imagine that the boost is high enough to worry about needing and intercooler.

TwinSupercharged

HOVBOY said:

Hi Fred awesome looking but no cooling by water or intercooler  any problems with preheated air? my intention is to fit a Graham unit on my 8 cyl Stude

With low compression, low boost and low top RPMs along with being momentarily (not a racer) into boost equals no requirement for inter-cooling. Graham made a SC just for an eight cly. as well. I have never seen one. If this is for a straight eight, that will be awesome! Keep us posted. I have SC teck and maint. sheets if you get into this project. E-mail me at xxxjfhaller@cox.net....drop the xxx

TwinSupercharged

MMickeyB said:

Those superchargers can't be easy to get, nor cheap.  Tremendous amount of engineering there.

The SCs are out there, I joined the Graham club and bought them off the classified. They are $250 to $300 each. But you have $800 to $1,000 to rebuild. It took me four units to equal two good units. The key is that the unit is a worm gear drive which are a matched set of gears. These sets are not available anymore, one needs to pick a sound set to begin with. 

VicTor Z

Seen this at San Clemente Outlets.