Edelbrock says "do NOT use Edelbrock"

[jlmccuan]

Well, it took me long enough, but I ran across some info on carb mods. There is more, and as I refind it I'll list it.

Here is an oldie but goodie

http://www.vs57.com/carb.htm

and another discussion forum

http://www.superchargersonline.com/forum/

Jim

_________1966 Avanti II RQA 0088______________Rabid Snail Racing

[jlmccuan]

I've found a good bit of help here. http://www.superchargerhelp.com/

Somewhere I have all the mods necessary to use an Edelbrock in a blow-through without the airbox. I'll post it when I come up with it again.

Jim

_________1966 Avanti II RQA 0088______________Rabid Snail Racing

[64V-K7]

I think the first concern that comes to mind in using any carb, behind a blower, is will the float collapse or distort..

Bob Johnstone

[sbca96]

Thats the difference between the drawn through and the blow through. A
GMC 6-71 blower is a draw through, the carb has the fuel air sucked
through it, thereby not needing to be pressure sealed. The Paxton is
a blow through, which forces pressure into the carb, and requires that
it be pressure sealed or leaks will occur :

6-71:



Paxton:



Tom

quote:Originally posted by 63r2
I bought a #1406 recently and in the owners manual it has a little section on blown engines which states " Two model #1405 carburetors should be used on engines with positive displacement superchargers such as GMC 6-71 blowers or equivalent".
It even suggests a calibration as the starting point for tuning.
I realise that it may not be a fair comparison to the typical Stude setup, however it proves that the carby is suitable for supercharger use.

[63r2]

Strange that they would not recommend a carby for supercharger use.
I bought a #1406 recently and in the owners manual it has a little section on blown engines which states " Two model #1405 carburetors should be used on engines with positive displacement superchargers such as GMC 6-71 blowers or equivalent".
It even suggests a calibration as the starting point for tuning.
I realise that it may not be a fair comparison to the typical Stude setup, however it proves that the carby is suitable for supercharger use.
I assume they will not recommend anything because it's going on a Studebaker motor and not the typical Ford/chev/etc application that they have done all the R&D for.
That said I will be putting my Carby in an R3 airbox and onto my Avanti.
pb

[bige]

My second spring is mounted in the typical Avanti spot...at the throttle bellcrank, stretched to the rear valve cover bolt. It actually works better than the two springs at the carb because I can use lower tension springs and get full closure.

The position of the carb spring is at the upper hole now. The present adapter for the 700R4 TV cable is different than the one in the picture and I had to move the spring upwards.

On my GM stuff I run the spring within the spring, it works well with a GM throttle cable.

I had an incident, when I was a kid...63 Tri-Power Bonneville, center carb closed but at least one didn't. Good thing it was back in "the old days", before locking steering columns, threw it in neutral and shut it off, without disaster. I'll never forget hurtling down a side street in a 4,000 pound land yacht with the girl I thought I was going to impress screaming and then looking at me like I was the biggest idiot in the world when we came to a stop. (G)

ErnieR

[JDP]

He has the correct spring, even the color is correct.

JDP/Maryland
63 R2 SuperHawk (Caesar)
spent to date $54664,75
64 R2 GT (Sid)
spent to date $62,839.60
63 Lark 2 door
51 Commander
39 Coupe express
39 Coupe express (rod)

[Dick Steinkamp]

quote:Originally posted by bige

Please Explain?

I think Jerry means throttle return spring. Two is usually a good idea to prevent unintended WOT. Studebaker put the additional one from the throttle bell crank to the valve cover. GM just ran a "spring within a spring".

[JDP]

You took my basic idea and expanded and improved it. Sort of like I suggested you might want to buy a watch, and you built one. Thanks for all the modifications you explained, I copied them to my notepad.

JDP/Maryland
63 R2 SuperHawk (Caesar)
spent to date $54664,75
64 R2 GT (Sid)
spent to date $62,839.60
63 Lark 2 door
51 Commander
39 Coupe express
39 Coupe express (rod)

[bige]

Please Explain?

[Jerry Forrester]

quote:Originally posted by bige

I have a Hybrid 1406 on my R2 Avanti. I took JP's idea of the AFB top on the Edelbrock bottom and did a couple of mods that have made the car perform better.

One change that would only be necessary with the AFB top installed is the use of the original AFB primary and secondary venturi clusters. The primary clusters of the Edelbrock have shorter vent tubes and rather than being separated from the air stream though the throats they would be exposed to it. I found that once I went to the AFB clusters throttle response and FUEL MILEAGE greatly improved. The secondaries had a slightly different configuration so I changed them also but it may not be critical, the primary change is. Before the change the car needed a larger jet to perform properly.

The second change is subtle and easy but helped eliminate a big drop in power at high RPM's. The secondary air flap on the Edelbrock doesn't lay flat like the AFB's. In a naturally aspirated sitiuation this positioning probably helps it open a little quicker. I think in a blow through situation it's angle allows it to be pushed shut or flutter at high RPM and full boost. A little grinding on the counterweight allows the flap to lay flat like the original R2 AFB.

The third mod is to make a hard connection on the secondary linkage. Both the AFB and the Edelbrock can benefit from this mod. The secondary plates are not directly connected to the primary. There is a fairly heavy spring that opens the secondaries once the tension from the primary linkage is released and the choke is fully open. If your choke isn't opened all the way the secondary plates on the AFB and the E Carb wont open but the pedal will still go to the floor. I may not be explaining it well but the bottom line is that full boost can overpower the spring pressure and keep the secondaries closed. I tack welded the linkage together although there may be other ways. I noticed an instantaneous change in full throttle performance after I did this.

I've spent LOTS of hours making the Hybrid carb work. The Avanti has run a best of 15.097 and gets 22 MPG on the highway with the 3.73's and the 700R4. It doesn't leak ( anymore than the original AFB did, mild seapage after lots of hard driving ), idles smoothly in the hottest weather and responds as crisply as any carbureted car possibly can.

My next mod is not to the carb itself but to use an "O" ring for the carb hat rather than a paper gasket to get a better seal and pick up a tiny bit of hood clearance.

ErnieR

Nice mods Ernie, but you need another spring.

Jerry Forrester
Douglasville, Georgia
Be sure to check out my eBay store
http://stores.ebay.com/CHROME-CHROME-CHROME_
for your shiny Stude stuff

More pix of Leo the '55 Pres HT here...http://tinyurl.com/2gj6cu

[bige]

I have a Hybrid 1406 on my R2 Avanti. I took JP's idea of the AFB top on the Edelbrock bottom and did a couple of mods that have made the car perform better.

One change that would only be necessary with the AFB top installed is the use of the original AFB primary and secondary venturi clusters. The primary clusters of the Edelbrock have shorter vent tubes and rather than being separated from the air stream though the throats they would be exposed to it. I found that once I went to the AFB clusters throttle response and FUEL MILEAGE greatly improved. The secondaries had a slightly different configuration so I changed them also but it may not be critical, the primary change is. Before the change the car needed a larger jet to perform properly.

The second change is subtle and easy but helped eliminate a big drop in power at high RPM's. The secondary air flap on the Edelbrock doesn't lay flat like the AFB's. In a naturally aspirated sitiuation this positioning probably helps it open a little quicker. I think in a blow through situation it's angle allows it to be pushed shut or flutter at high RPM and full boost. A little grinding on the counterweight allows the flap to lay flat like the original R2 AFB.

The third mod is to make a hard connection on the secondary linkage. Both the AFB and the Edelbrock can benefit from this mod. The secondary plates are not directly connected to the primary. There is a fairly heavy spring that opens the secondaries once the tension from the primary linkage is released and the choke is fully open. If your choke isn't opened all the way the secondary plates on the AFB and the E Carb wont open but the pedal will still go to the floor. I may not be explaining it well but the bottom line is that full boost can overpower the spring pressure and keep the secondaries closed. I tack welded the linkage together although there may be other ways. I noticed an instantaneous change in full throttle performance after I did this.

I've spent LOTS of hours making the Hybrid carb work. The Avanti has run a best of 15.097 and gets 22 MPG on the highway with the 3.73's and the 700R4. It doesn't leak ( anymore than the original AFB did, mild seapage after lots of hard driving ), idles smoothly in the hottest weather and responds as crisply as any carbureted car possibly can.

My next mod is not to the carb itself but to use an "O" ring for the carb hat rather than a paper gasket to get a better seal and pick up a tiny bit of hood clearance.

ErnieR

R2 R5388
Tack weld at the screwdriver tip.

[PlainBrownR2]

It sounded like in the first query Edelbrock expected to hear, and looked up, a draw through setup. They didn't expect to be looking for a carb for a blow through setup. I'd almost want to go back, provide the Studebaker specifications, VE, etc, and ask what they have in a sealed carb for a blow through setup. What throws me is they didn't go look up the sealed carb for the blow through setup. Far as I know their site only provides a few models for this application. I've attempted the sealing and vent redrilling of a 2bbl vented carb, never used it though. That said I prefer the R3 airbox, less fuss, and no need to pull a carb completely apart. I'll vie that you made need the expertise of the Studebaker people. Get a number and then go back to Edelbrock and look it up for your application. Somebody like Harbit, T-Bow, or Myers might have some input .

I wonder if the 1806 is the R1 setup, with the external vents? Since they went looking for a draw through where the pressure is under instead of above the carb(blow through), thats why they said the carb wouldn't work without modification.


1964 Studebaker Commander R2 clone
1950 Studebaker 2R5 with 170 turbocharged
[img=left]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00003.jpg?t=1171152673[/img=left]
[img=right]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00009.jpg?t=1171153019[/img=right]
[img=left]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00002.jpg?t=1171153180[/img=left]
[img=right]http://i158.photobucket.com/albums/t102/PlainBrownR2/DSC00005.jpg?t=1171153370[/img=right]

[JDP]

They told me no also. I moved the R2 top over and used it on 3 R2's so far without a issue.

JDP/Maryland
63 R2 SuperHawk (Caesar)
spent to date $54664,75
64 R2 GT (Sid)
spent to date $62,839.60
63 Lark 2 door
51 Commander
39 Coupe express
39 Coupe express (rod)

[Chris Collins]

I've been following the Edelbrock threads too, thinking of an eventual upgrade for my R2+ pressure box Avanti. While the box takes care of the sealing issue, I presume you would have to re-use the old mechanical choke, instead of the electric one. To me that takes away some (but not all) of the benefits to changing.

Given today's lawsuit-happy environment, it is so much easier for a company to say "No" to any application that sounds a bit unusual, especially if something like the fuel system is involved. It may be understandable, but still frustrating.

It may take longer, but the real-world experience of other Stude people may be the only source of answers to help make a decision.

Chris Collins
63 Avanti R-2
66 Cruiser