Sterile Unmarked ChiCom Weber Copies

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Re: Sterile Unmarked ChiCom Weber Copies

Post by farmer » Mon Dec 26, 2016 7:12 am

Hello.
I have come across these carbs on Ebay too for a while, and have been very much in doubt whether it was a Decade, Fajs or an Empi copy with out marks. I have not bought any yet, but was planning on getting a set here in january to see if they would hold up on quality and even more functionality.
The problem in general with the copy IDF´s is not idle or WOT, but everything in between. Especially the transition area can be a real nightmare. The HPMXés gen 2 & 3 are normally reasonably easy to get to run right. The Decade and the Fajs are just about impossible. That said, the horizontal Fajs are actually not that bad, so it would maybe be possible to correct the vertical without too much hazzle.

If I get around to it I will write my findings here. Otherwise we will have to wait and see what FJC finds out.

T

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Re: Sterile Unmarked ChiCom Weber Copies

Post by Marc » Mon Dec 26, 2016 9:11 pm

FJCamper wrote:...We're setting them up with 36mm venturis...
What I.D. chokes do they ship with? I missed that if it was mentioned...

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Re: Sterile Unmarked ChiCom Weber Copies

Post by FJCamper » Tue Dec 27, 2016 10:28 am

The 40mm IDF copies ship with very nicely finished cast 28mm vents. That's all I've seen so far. I've got a set of EMPI 44 IDF's here already and only bought the 40's.

FJC

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Re: Sterile Unmarked ChiCom Weber Copies

Post by Marc » Tue Jan 03, 2017 3:55 am

Do these use the same 10/32.5mm float settings as the original Italian IDFs or should they be set somewhat lower? I've been looking about online and there doesn't seem to be much consensus.

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Re: Sterile Unmarked ChiCom Weber Copies

Post by FJCamper » Wed Jan 04, 2017 9:38 pm

Hi Marc,

The float level on both carbs was the same out of the box, almost exactly the 10.5-11.5mm (32mm) as specified by Weber. The interior of the carbs was very clean. The only oddity was most of the screws, to include jet stacks, were really, really tight.

FJC

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Re: Sterile Unmarked ChiCom Weber Copies

Post by FJCamper » Fri Mar 10, 2017 3:47 pm

Image

Unmarked ChiCom Weber Copies Update

We have our set mounted and have learned a few things.

Apparently these carbs are not shipped in pairs of left and right configurations. and require reversing of the fuel inlet to face forward on the right hand carb (shown above), and reversing the levers on the throttle shaft on the driver's side.

Technically, these are copies of 40 IDF Webers, but in reality copies of the EMPI HPMX 40-44 IDF copies. The big difference between original 40 IDF's and the EMPI HPMX's is the Italian-Spanish 40 IDF's are really a 40mm bore, whereas the EMPI's are actually 44mm bore. That means original 40mm venturis for the Italian-Spanish will not fit the unmarked ChiComs.

But, for some reason, the throttle plates are just 40mm, not 44mm. A distinction without a big difference, just to say they have both sizes? The obvious way to beat the system would be to buy the 44mm ChiCom or EMPI and adapt to small or large displacement engines by reducing venturi diameters.

We're going the opposite way, and running the 40mm throttle plates with 36mm venturis in anticipation of 6000 and 7000 RPM sprints. We have all venturi steps from 28-30-32-34-36 and even 38mm for tuning. Why? The classic throttle bore for Porsche 1600cc engines was 40mm once Porsche ditched its problematic 2-bbl Zenith carbs and went to the absolutely superior twin-choke Solex 40PII, a copy of the 40 IDF in external appearance.

40PII's came with 28mm vents stock, and up to 32mm for racing. Vintage Porsche racers use 40PII's today with 36mm venturis.

Once we had the ChiCom 40's mounted, as a test we touched no bleed screws or idle adjustments, flipped on the fuel pumps, and pressed the starter button. The engine fired off almost immediately, and settled into a steady, even idle.

With a little warmup, we could get 3000 RPM runups with no problem, no backfires, no hesitation.

Next to go to Barber for a track day 0102 April, to test and tune for The Mitty at Road Atlanta April 20-23.

FJC

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Re: Sterile Unmarked ChiCom Weber Copies

Post by sideshow » Fri Mar 10, 2017 9:36 pm

They copied EMPI??? that is not what I would wish the low cost leader to make an even cheaper version of.
Yeah some may call it overkill, but you can't have too much overkill.

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Re: Sterile Unmarked ChiCom Weber Copies

Post by Piledriver » Fri Mar 10, 2017 9:39 pm

EMPI bought Bugpack, perhaps they are trying to improve their game...
I do suffer from being an optimist.

The Chinese can make perfectly good anything when they have reason to.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

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Re: Sterile Unmarked ChiCom Weber Copies

Post by sideshow » Fri Mar 10, 2017 9:46 pm

A copy of crap is unlikely to improve.

Bugpack brings a tear to my eye, they went from being one of the worst crap peddlers around competing with EMPI for the worst products ever...to actual usable products. They even started building quality stuff in the US, and innovating better parts.

Now the logo is property of EMPI, I would expect kuality to follow.
Yeah some may call it overkill, but you can't have too much overkill.

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Re: Sterile Unmarked ChiCom Weber Copies

Post by FJCamper » Thu Mar 30, 2017 2:04 pm

Image

We have the ChiCom 40IDF's set up with 36mm vents, 200 airs, 135 mains, and .55 idles. The idles really made the difference in tuning.

The inscrutable little varmints idle well and rev. No overrich fumes or black smoke. No popping, no backfires, all suspiciously good.

I was concerned I'd gone a size or two too far up on the venturi, until the first test drive. Nope. The Ghia reared up and took off.

We will be at Barber for a test day Sunday.

FJC

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Re: Sterile Unmarked ChiCom Weber Copies

Post by Lingwendil » Sun Apr 16, 2017 12:02 am

That's good to hear that these seem to work so far. I might try and get a set for my 1776 to play with.

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