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BugMan114
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Joined: March 22, 2007
Posts: 3744
Location: Ellenwood, GA
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 Posted: Sun Jul 04, 2010 8:38 pm Post subject: Twin Judsons |
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Hi yall. I remember a pic floating around here somewhere about a motor that had twin judson superchargers on it (can't remember if it was a 40 horse, or a 36 horse). I can't seem to find the pic, but it was an old black and white pic (i'm guessing from the 50's or 60's). I was just wondering if anyone seems to have any more info about it, or if anyone had done, or even attempted this mod before?
I've heard that with a judson, you are pretty much limited to a stock motor, or else you'll surpass what the blower is capable of. But if you were to add two of them, i would think this would open up possibilites to larger heads, better cam, larger displacement, etc. Thanks in advance
-Mike
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1974 Super Beetle: Custom resto in progress
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John Moxon 
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Joined: March 07, 2004
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Location: Southampton U.K.
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Kais Collection
vintage treasures
Joined: February 18, 2005
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Location: Rotterdam, The Netherlands
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John Moxon
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ProjectX
Accessory Nut
Joined: May 01, 2006
Posts: 1014
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| Posted: Mon Jul 05, 2010 7:50 am Post subject: |
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| kai wrote: |
so who has the guts to do it??   |
It's about time you stepped up and show us your skills Kai... sell a few of those plate frames and ........ 
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Kais Collection
vintage treasures
Joined: February 18, 2005
Posts: 1570
Location: Rotterdam, The Netherlands
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| Posted: Mon Jul 05, 2010 8:54 am Post subject: |
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| 56OvalRHD wrote: |
| kai wrote: |
| so who has the guts to do it?? |
It's about time you stepped up and show us your skills Kai... sell a few of those plate frames and ........ |
I'd have to sell all of them, and then still would come up short Eric..
It would be a cool project to do though, once the Speedwell kit is in the ghia.
My girl Luna has been saying for years that double Judson's can (and should) be done..
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BugMan114
Samba Member
Joined: March 22, 2007
Posts: 3744
Location: Ellenwood, GA
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| Posted: Mon Jul 05, 2010 9:22 am Post subject: |
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Thanks so much. But whats with the generator nuts? it seems the shaft is so long, that one of those early big nuts are installed, as well as a later model cap (the piece that holds the extra shims), is backwards, and a regular nut over. whats the deal with that?
Anyhoo. It seems that now you have double the airflow, that would open up possibilities to larger heads, and other things.
_________________
1974 Super Beetle: Custom resto in progress
1972 Super Beetle: Daily Driver
1971 Std. Beetle w/ 1929 Mercedes Benz Gazelle kit
1960 Baja Bug
1969 Baja Bug
Sand Rail- Homemade
Sand Rail- FUBAR
Aircooled Airheads
Why the hell do they call it a gland nut. its obviously a big fat bolt!!! |
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James D
Samba Member
Joined: July 17, 2007
Posts: 236
Location: Germany
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| Posted: Mon Jul 05, 2010 10:48 am Post subject: |
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| BugMan114 wrote: |
Thanks so much. But whats with the generator nuts? it seems the shaft is so long, that one of those early big nuts are installed, as well as a later model cap (the piece that holds the extra shims), is backwards, and a regular nut over. whats the deal with that?
Anyhoo. It seems that now you have double the airflow, that would open up possibilities to larger heads, and other things. |
Perhaps he had to backspace the fanbelt pulleys to allow room for the dual belts for the Judsons?
You wouldn´t necessarily need the biggest valves or wildest cam with a blower(s) as there is already a pressurised fuel/air charge building up in the inlet, just waiting for the valve to open. Big valves couldn´t hurt though, I suppose...  |
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grueni
Samba Member
Joined: November 03, 2008
Posts: 582
Location: Germany
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| Posted: Mon Jul 05, 2010 12:23 pm Post subject: |
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at first..twice the parasitic power makes no sense with judson also double bad in fact of the fan cantact to the housing. at the end this all is more stress to the crank + thermal overkill in compare to the power it gives.
but it looks cool for sure!
big valves are the supercharger's best friend.
for example: my 1200cc 36er and 17psi of boost the same power i could build with a 40hp 1200cc and 1300dp heads(35,5x32mm valves) and half of boost at same rpm.
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Altema
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Joined: June 20, 2010
Posts: 2906
Location: Lower Michigan
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| Posted: Mon Jul 05, 2010 5:18 pm Post subject: |
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| kai wrote: |
| so who has the guts to do it?? |
I've got the guts, but not the money 
Seriously though, the parasitic losses would be a major problem like stated by grueni; twice the friction, twice the strain on the crank and bearings. You could reduce the strain by using a single serpentine cogged belt with cogged pulleys, and just line up all the pulleys. But, there is no way to reduce the internal friction of the Judsons unless you coat the internal housing surface, vanes, and vane slots. The cogged belt would kind of ruin any hopes of appearing vintage though.
Paul |
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BugMan114
Samba Member
Joined: March 22, 2007
Posts: 3744
Location: Ellenwood, GA
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| Posted: Mon Jul 05, 2010 5:41 pm Post subject: |
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a triple belt instead of two would look badass .
I mean if one judson increases power, its also taking away from the motor a little. But with two, sure you have twice the parasitic loss, but then again, you have twice the gain. Can anyone give an approxamate HP on a motor like this? if i an hearing this right, a judson on a stock 36hp motor gives about 57 to the wheels. so with two and maybe some big valves, you might be around 80hp?
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1974 Super Beetle: Custom resto in progress
1972 Super Beetle: Daily Driver
1971 Std. Beetle w/ 1929 Mercedes Benz Gazelle kit
1960 Baja Bug
1969 Baja Bug
Sand Rail- Homemade
Sand Rail- FUBAR
Aircooled Airheads
Why the hell do they call it a gland nut. its obviously a big fat bolt!!! |
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GeorgeL
Samba Member
Joined: January 16, 2006
Posts: 7346
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| Posted: Mon Jul 05, 2010 6:01 pm Post subject: |
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| BugMan114 wrote: |
a triple belt instead of two would look badass .
I mean if one judson increases power, its also taking away from the motor a little. But with two, sure you have twice the parasitic loss, but then again, you have twice the gain. Can anyone give an approxamate HP on a motor like this? if i an hearing this right, a judson on a stock 36hp motor gives about 57 to the wheels. so with two and maybe some big valves, you might be around 80hp? |
Nope, doesn't work that way.
There is a limit to the amount of air you can cram into the engine without bad effects. To use some round numbers, consider that your compression ratio is 8:1. If you run 7PSI of boost (1/2 atmosphere) you will get an effective CR of 12:1 which is getting into detonation territory.
The only purpose to running two S/Cs is if one S/C cannot supply the flow you want at the boost you want. That would imply that you either have greatly increased displacement or are running at much higher RPMs.
So, you might want to run dual Judsons on a large type IV where the increased displacement might require more flow.
I think in this case the goal is more aesthetic than practical. Two Judsons makes someone the Alpha Dog of the show from the moment their car rolls out of the trailer until they push it back into the trailer. |
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BugMan114
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Joined: March 22, 2007
Posts: 3744
Location: Ellenwood, GA
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| Posted: Mon Jul 05, 2010 9:20 pm Post subject: |
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well the idea would be to increase displacement, as well as use larger valves. if one jusdon was good for 1200cc's, wouldn't 2 be good for 2000-2400cc's, if airflow was the main issue here? perhaps this could be used on a late model 1600 increased to 2000cc's (perhaps a 2074cc, or 2110) i would think this could be made to be streetable. just a thought
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1974 Super Beetle: Custom resto in progress
1972 Super Beetle: Daily Driver
1971 Std. Beetle w/ 1929 Mercedes Benz Gazelle kit
1960 Baja Bug
1969 Baja Bug
Sand Rail- Homemade
Sand Rail- FUBAR
Aircooled Airheads
Why the hell do they call it a gland nut. its obviously a big fat bolt!!! |
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GeorgeL
Samba Member
Joined: January 16, 2006
Posts: 7346
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| Posted: Mon Jul 05, 2010 9:24 pm Post subject: |
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| BugMan114 wrote: |
| well the idea would be to increase displacement, as well as use larger valves. if one jusdon was good for 1200cc's, wouldn't 2 be good for 2000-2400cc's, if airflow was the main issue here? perhaps this could be used on a late model 1600 increased to 2000cc's (perhaps a 2074cc, or 2110) i would think this could be made to be streetable. just a thought |
That's why I mentioned the type IV engine. However, going that way kinds of corrupts the whole Judson vintage speed mystique. |
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BugMan114
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Joined: March 22, 2007
Posts: 3744
Location: Ellenwood, GA
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| Posted: Mon Jul 05, 2010 9:31 pm Post subject: |
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yeah, but cmon, if you see a 1600 based motor, with TWO judsons, you know you'd stop and drool all over it, lol. 1600, 25hp, their all the same, 1600's are just cheaper, and faster, 36hp's are older, slower, expensive as hell to mess with, but much MUCH sexier . besides, a 40 horse looks almost the same as a 1300, or 1600. I personally can't tell the difference, unless i see the case numbers, lol
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1974 Super Beetle: Custom resto in progress
1972 Super Beetle: Daily Driver
1971 Std. Beetle w/ 1929 Mercedes Benz Gazelle kit
1960 Baja Bug
1969 Baja Bug
Sand Rail- Homemade
Sand Rail- FUBAR
Aircooled Airheads
Why the hell do they call it a gland nut. its obviously a big fat bolt!!! |
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krusher
Samba Member
Joined: September 24, 2002
Posts: 7662
Location: europe
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| Posted: Tue Jul 06, 2010 12:18 am Post subject: |
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| BugMan114 wrote: |
| yeah, but cmon, if you see a 1600 based motor, with TWO judsons, you know you'd stop and drool all over it, lol. 1600, 25hp, their all the same, 1600's are just cheaper, and faster, 36hp's are older, slower, expensive as hell to mess with, but much MUCH sexier . besides, a 40 horse looks almost the same as a 1300, or 1600. I personally can't tell the difference, unless i see the case numbers, lol |
Just standing there drooling in the uneducated "bigger is better" state of mind , after the great explanations of why 2 would not work, you would be a fool standing there drooling over something that did not work.
Is that why people love chrome?
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Last edited by krusher on Tue Jul 06, 2010 10:03 am; edited 1 time in total |
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John Moxon
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Kais Collection
vintage treasures
Joined: February 18, 2005
Posts: 1570
Location: Rotterdam, The Netherlands
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| Posted: Tue Jul 06, 2010 1:03 am Post subject: |
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| John Moxon wrote: |
| If you know how tight it is under the decklid with one Judson just imagine the problems with two. |
Stick it in a barndoor
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Jacks
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Joined: July 15, 2006
Posts: 2442
Location: San Clemente, Ca.
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| Posted: Tue Jul 06, 2010 8:07 am Post subject: |
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| krusher wrote: |
| BugMan114 wrote: |
| yeah, but cmon, if you see a 1600 based motor, with TWO judsons, you know you'd stop and drool all over it, lol. 1600, 25hp, their all the same, 1600's are just cheaper, and faster, 36hp's are older, slower, expensive as hell to mess with, but much MUCH sexier . besides, a 40 horse looks almost the same as a 1300, or 1600. I personally can't tell the difference, unless i see the case numbers, lol |
That's just standing there drooling in the uneducated "bigger is better" state, after the great explanations of why 2 would not work, you would be a fool standing there drooling over somthing that did not work.
Is that why people love chrome? |
That's why people use dual 48's  |
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doveblue3
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Location: Florida
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| Posted: Tue Jul 06, 2010 12:39 pm Post subject: |
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| If you are going to use 2, at least stack them..... |
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