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Old 07-11-2011, 08:02 AM
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Caprimaniac Caprimaniac is offline
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Join Date: Sep 2006
Location: Skjetten, No
Cobra Make, Engine: Unfortunataly ; none
Posts: 333
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Default Needle valve & seat

Dear fellow Weber drivers.....

I went racing this weekend, and this time I really felt like converting to injection....

I had some big troubles getting the engine to drive properly; it was stumbling and clearly some of the cylinders didn't fire as or when they should.

I friend came up with a theory that the carbs were struggling to get enough fuel and that larger inlets to the float chambers were needed. We are talking needle valve & seat. I have seen little discussion of this here. And I couldn't find it in 13's great little table either.

A look through my setup show the needle & seat are 200.
As far as I can tell, these are the smallest type for the IDF's (200, 225 and 250 are listed in the partslist I have).

For IDA I find 200 and 300 + they also have an inlet ball valve whereof 16 different are listed.

Another cause for the Webers not doing the job right might be high cornering forces: We were pushing 99- 100% (ending out in the sand) going in powerdrift with Michelin racing slicks.

The engine has caused me headscratching before not doing as expected while going around the track; loosing mid- rpm out of the corner punch is not very funny!

I'd be thankful for any input on the matter.
(I'd like to add that my idle quality was not 100% with at lease 1 carb out of sync, which migth have caused some of the trouble. Anyway, the car went as a rocket in high RPM straightline; 7800 in 4. equals somewhere like 250 km/h)

By the way, it almost ended like thisRøykfull gatebilfestival | sa.no but luckily, we did put in a new windscreen later that evening.
Rock on!
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