Holley/Weber vacuum secondaries

[82a]

buncha options out there, starting a thread

 

[82a]

first bit of big news, the 5220 variant holley/weber is available with VOS, however, the 6520 is computer controlled

i've seen them selling for 60 bucks rebuilt

 

[Ansimp]

I would not be using a vacuum actuated secondary on performance (lower manifold vacuume) applications. I like the idea of going to a 2 barrel carby that has a mechanical secondary so fuel/power delivery is directly linked to throttle position. I wouldn't want the secondary delivery to feel like a turbo coming on boost and providing squirrelly handling of the GW.

 

[joedrum]

yes I too would not recommend going down this road ..it leads right back to where we have tried to get away from

 

[82a]

hmmm looks like i have this backwards :smilie_happy:, folks have tried out these carbs?

i was thinking that some of the bogging issues may have been due to mechanical secondaries

 

[dan filipi]

I've never tried a carb with vacuum secondary so can't say how it would perform but the bogging issue is mostly right off idle, a long way before the secondary comes into play.

This brings up a good point though about the secondary.
On my rebuilt 32/32 both the primary and secondary throttle plates were not perfectly aligned in the carb bore. Only very slightly off but after aligning it seemed to reduce bogging a tiny amount.

 

[82a]

https://www.chevelles.com/forums/showthread.php?t=247722

https://www.carcraft.com/techarticles/se ... ight_carb/

all road demon carbs have vac secondaries

 

[joedrum]

nope not me I want full control

 

[dan filipi]

joedrum » Sun Dec 29, 2013 11:17 am[/url]":6n04bt4h]
nope not me I want full control

Yeah me too.
Too much variable possible in relying on a vacuum.

 

[sparrowhawkdesign]

I believe there is also an issue with the amount of vacuum available from the GL engine compared to a car engine??????

 

[joedrum]

hard to adjust that ...I agree

 

[82a]

sparrowhawkdesign » Sun Dec 29, 2013 2:24 pm[/url]":1ap36ep0]
I believe there is also an issue with the amount of vacuum available from the GL engine compared to a car engine??????

dunno but i've seen lotsa teeny cc fiat engines and webers with vac secondaries

 

[joedrum]

yes they seemed to be big secondary's too

 

[slabghost]

82a » Sun Dec 29, 2013 2:44 pm[/url]":2jvuyg69]

sparrowhawkdesign » Sun Dec 29, 2013 2:24 pm[/url]":2jvuyg69]
I believe there is also an issue with the amount of vacuum available from the GL engine compared to a car engine??????

dunno but i've seen lotsa teeny cc fiat engines and webers with vac secondaries

Never know until you give it a try. You might be onto something. So far the fiat carbs have cost more used than those Tom sells but they are very similar I think. :headscratch:

 

[82a]

here's a clony weber for a small fiat
https://www.ebay.ca/itm/fiat-125p-carbur ... 71&vxp=mtr

lotsa cheaper used real webers out there too
https://www.ebay.co.uk/itm/FIAT-1300C-15 ... 0940828042

Here we have a used Weber 34 DCHD 1 1K carburettor. I can't say exactly what it's for but having looked on Google it appears as though 1960's/1970's Fiats with 1300, 1500 and 1600 engines appear to be in the frame.

 

[sparrowhawkdesign]

I have a friend who's business is working with old Fiats. He does everything from Webers to FI. For some reason I can't explain the Fiat engines have more vacuum than the GL's. I need to go talk with him soon and see if he has an answer.

 

[badorderbob]

As for price,..that's a joke compared to Toms' Carb and his is new too!!: Of course that's here in the States !!! :wave:

 

[Ansimp]

sparrowhawkdesign » Mon Dec 30, 2013 5:24 am[/url]":1k8paln5]
I believe there is also an issue with the amount of vacuum available from the GL engine compared to a car engine??????

+1