46 IDAs

[Phil West]

I've not used 46 IDAs before - just wondered if they are any good for race/hot street?  Is the body outside the same size as the 48 IDA i.e do they fit 48 manifolds and linkages.

Thanks
Phil

[Erlend / bug66]

Bet you could sell them, and get several set of 48 IDAs..

[richie]

Phil

bolt pattern is same, they used to do manifolds for 46idas with smaller top hole, think it was Sauer & son in Germany, we have a pair I am going to use on a hot 912 engine we are doing for Jo's 912, I think on a smaller capacity engine[sub 1900cc] they should work better

cheers Richie

[Phil West]

Bet you could sell them, and get several set of 48 IDAs..

They sound like they are pricey - any idea of value for a pair?

[Bruce]

Bet you could sell them, and get several set of 48 IDAs..

They sound like they are pricey - any idea of value for a pair?

They are the correct carb for a Porsche 904. Since the cars are worth millions and the carbs are quite rare......

The only difference in the main body is that the bore below the venturi is 2mm smaller.  Otherwise everything else is identical.  
The 46 IDA has an extra part not found on a 48.  There's a small collar around the push rod for the pump to limit it's travel.
See part number 66 in this diagram:


If we're lucky, maybe Jim Ratto will jump in here with the original jetting the 904 needed.  Am I correct in thinking they used F14 tubes?

[dth]

A few years ago me and a friend bought a V8 inlet that had 4x 46 IDA,s on it , thought it was a
mistake when i seen it advertised , guy confirmed it , didnt pay over the odds for it, we sold the carbs
and the inlet , probably for not enough but we made a few pounds , i think Jim Calvert has has a set
fitted to to his Saltzberg rally beetle now  , so went to a good home

[Jim Ratto]

Yeah and what a weird tube the F14 is. Unlike any other IDA series tube really.
I'd have to dig my books out, but from memory, it's the placement of the top air holes that make the F14 so odd.
And why it was set up like this must correlate to the extreme valve timing they used in the race version of the T-587 Carrera motor. The 46IDM was used on 356 Carrera "2000 GT" for sports use, with F11 or F20 tubes, depending on exhaust system.

I think 904 ran 60x120 idle, 3.00 needle valve, 170 main, 130 air and those alien F14's. The Street 4 cam (356) with IDM ran 60x120, 165 main, 3.00 needle, 240 air (I think) and either F11 or F20. For Le Mans use, Porsche said to run a 175 main..

I'll dig the books out later and post a diagram of the F14

[Phil West]

I took a road trip today to see a man with 10 IDAs.  Only 4 of them were 48s so I bought them.  The other 6 were 46s but I was concerned about sourcing manifolds so I left it.  By the looks of it all I would have needed to do was bore the bottom channel and fit new butterflies to make some 48s.

Anyway far more more interesting was the sheds and workshop he had were the most amazing thing I've ever seen.  He had a staggering amount of equipment in there that was just jaw dropping.  As I passed the 10 huge mills and admired the massive flow bench next  to the crank balancer I realised I was standing on the rolling road which was next to a dyno as well.  That was just the first building.  All I could keep saying was the f word.  Boring machines, grinding lapping you name it.  Makes his own cams, cranks.  A draw containing 50 titanium rods.  About 1000  rods hanging from the ceiling.  Valve lappers Spring crack testers shim grinders plasma cutters 6 huge lathes it just went on  and on.  All this is a quiet cul-de-sac residential bungalow.

Amazing!

[dth]

Sounds great , love places like that  , i suppose welding up the manifolds and boring them back out to 46 would work
if some one really wanted to go with the 46 butterfly.

[alex d]

I took a road trip today to see a man with 10 IDAs.  Only 4 of them were 48s so I bought them.  The other 6 were 46s but I was concerned about sourcing manifolds so I left it.  By the looks of it all I would have needed to do was bore the bottom channel and fit new butterflies to make some 48s.

 
so 3 pairs of 46s?? it's not like those grow on trees!

[Eddie DVK]

I took a road trip today to see a man with 10 IDAs.  Only 4 of them were 48s so I bought them.  The other 6 were 46s but I was concerned about sourcing manifolds so I left it.  By the looks of it all I would have needed to do was bore the bottom channel and fit new butterflies to make some 48s.

 
so 3 pairs of 46s?? it's not like those grow on trees!

Yes and the million dollar question how much is he asking for a pair?

[fish]

I would love to get my hands on some 46IDAs for my period build 2180 Fumio heads.

[spanners]

All that glitters gentlemen,,,,,,, you can't turn the clock back, age,,, Jim Calvert sourced some from Europe for the Salzburg rally car project, he's all but abandoned hope of getting them sorted despite all the resources available to him, he took spare weber IDFs and manifolds on the Eifel rally, needles to say they were used for the event, a Spanish event looms in just a few weeks, it's not looking good for the 46s..

[Jim Ratto]

back on Porsche application with these, sorry cannot find my Weber book with dimensions of the F14, but what I remember is the F14 is super thick diameter, like fatter than F11 (!) and with top air holes way up high, and I think not many other. Why? From what I have read the thick diameter has an extreme "braking" effect on fuel level in well, and is supposed to cancel out effects of strong pulsations from intake signal. But the larger diameter, the less volume of fuel available on instant demand in the well. So I don't get it. The high air holes seem to mean they were shooting for an early admission of air into main circuit.
What's also interesting is Porsche used the 48IDM (predecessor to IDA) on smaller 1.5, 1.6 and 1.7 4-cam motors, those most of these were used in single-seat, real light formula cars, and sports cars. The formula cars had real close ratio 6 sp gearboxes. If you read Sloniger's book, somebody mentions that under 5000 rpm, lights were completely out, there was nothing but gasping carbs, and then above 5000 it was all hell breaking loose. When Porsche tried the 48IDA on the 904 Carrera they determined the 48mm carbs were too big (?) and went with 46mm. Which is weird as the 904 motor was almost 2 L, (1966cc) and by 1965 had some of the wildest valve timing Porsche had ever (and would ever) use.

[K-Roc]

Hey Jim is this the F14?   ( image from fleabay)

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[Jim Ratto]

Yep, that's the one. Weirdo tube.

[Udo]

You can keep the 48 maifolds like they are ,but those 46 are very rare and expensive . We had a time like 20 years ago someone in germany had some sets and bored them to 51 :-( because nobody wanted them

Udo

[Phil West]

/Quote
Yes and the million dollar question how much is he asking for a pair?




Guess I should maybe have bought 'em all!  I've got a friend who is likely buying them soon, I'll let you know then.

[Bruce]

What's also interesting is Porsche used the 48IDM (predecessor to IDA) on smaller 1.5, 1.6 and 1.7 4-cam motors,

Didn't Porsche use the 46IDM on the first 904s?

[Jim Ratto]

Yeah looks like it, according to Sloniger's book. I've seen one factory photo of a 904 frame with motor and in the picture the carbs look more like IDM, than IDA (the steps in casting look more pronounced)

[fish]

I remember reading somewhere that 46 IDAs were used on a European Rally bug 1600cc with open chamber heads.
One of my mates and mentors also used them on circuit/hillclimb 2110cc bug with awesome results, he still holds a local circuit class record that stood for some years and cannot be beat because the circuit has since closed.

[Bruce]

Yeah looks like it, according to Sloniger's book. I've seen one factory photo of a 904 frame with motor and in the picture the carbs look more like IDM, than IDA (the steps in casting look more pronounced)

Can you post a pic?
Here's a section of an F14.  I don't know what that other tube is.
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[Bruce]

...... the F14 is super thick diameter, like fatter than F11 (!) and with top air holes way up high, and I think not many other. Why? From what I have read the thick diameter has an extreme "braking" effect on fuel level in well, and is supposed to cancel out effects of strong pulsations from intake signal. But the larger diameter, the less volume of fuel available on instant demand in the well. So I don't get it. The high air holes seem to mean they were shooting for an early admission of air into main circuit.

Have you ever tried F14s? 

[modnrod]

I remember reading somewhere that 46 IDAs were used on a European Rally bug 1600cc with open chamber heads.

Salzburg rally beetles?

The heads interest me too...........

[Jim Ratto]

...... the F14 is super thick diameter, like fatter than F11 (!) and with top air holes way up high, and I think not many other. Why? From what I have read the thick diameter has an extreme "braking" effect on fuel level in well, and is supposed to cancel out effects of strong pulsations from intake signal. But the larger diameter, the less volume of fuel available on instant demand in the well. So I don't get it. The high air holes seem to mean they were shooting for an early admission of air into main circuit.

Have you ever tried F14s? 

No, I haven't.

[Phil West]

Here's the stash......

[Eddie DVK]

Damn 

[alex d]

 

what are those manifolds? 4-cam carrera engine maybe? the stories those carbs could tell!

[Phil West]

They are for minis.  He did also have another few sets of carbs but wanted to keep those as spares.  So there were loads!