Hose connections differences on EU / USA ?

Hi, does anyone know why the diagrams show reversed vacuum hose connections on the USA spec from the EU spec on a 1981 308 injection model?
Can they be reversed as I’m trying to eliminate some of the unwanted complicated stuff on a US model to make it more compatible with EU spec ?
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My guesses would be:

1. They just made a mistake in the US SPC figure (and I see the same difference in the OM Section 3 injection system figures). I also noted that they made a similar mistake in the figure on page D8 of the Mondial 8/QV WSM where the vacuum downstream of the throttle plate would tend to take the WUR diaphragm downward; whereas, the text on page D12 says the vacuum downstream of the throttle takes the WUR diaphragm upward (with the D12 text seeming correct, based on the WUR drawing on page D13, with the logic that less vacuum = diaphragm not pulled upward so much = WUR valve more open = lowers control pressure = adds enrichment).

2. The euro and US use different throttle bodies, and the ports have different functions (although I think this unlikely just due to the port placement on each). Do you have the Ferrari PN for the US throttle body? The euro is now 117357 (was 114720), but I don't have access to the US SPC (although this can be a little inconclusive as just a small minor change, like adding another port for something else, will cause a part number difference).

One sure functional check you can do is, when at warm idle, if you blip the throttle = the control pressure should go down momentarily adding enrichment. Or under sustained hard acceleration (less vacuum), the control pressure should go down adding enrichment.

 

Hi Steve
The throttle body for US models is part number 115633 which apparently is superseded by 117080
I guess I can try to connect hoses up as per EU spec and see what happens. It’s all part of the plan to simplify things and remove the cold start valve as I don’t really like the engine revving like mad from cold



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Went thru the photos of US version 308i engines that I have saved over the years, and they do seem to be hooked up like that US SPC figure -- so I have no idea of what's going on . Unfortunately, I don't seem to have any euro version 308i engine photos. Here are the US version 308i engine photos showing the WUR vacuum line connections:
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But I'd still say that the functional test is valid: less intake manifold vacuum should = lower control pressure = adds enrichment.

 

Also to throw in the mix, there's two different WUR's. The made in "France" version, don't have the PN off hand, is pressure sensitive to boost. It's a rare WUR in the US but found on the euro engines. Also found on the turbo Porsche and Saab I think as well of that era.

 

Thanks Steve
I’ll look at that when I get a chance
Would you like a copy of the 308 GTSi US parts catalog for your reference I have on pdf ?
Regards


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Hi,

Both ports get different pressure signals. You cannot mix that (...ok you can...). The hoses have different diameters, so Bosch tells you how to connect.
One signal is behind the throttle. The other one is in front of the throttle.

I don´t know the english word for the german "Volllastanreicherung". It is not to go lean.
Paul

 

Thanks Paul
Yes true the 2 hoses have different diameters so I’ll keep them the original way round, I’m still going to delete other items that aren’t needed for pollution control here in France


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Yes, please! Can you post a link to it, or would you need to email it to me (is it a big file?).

 

This is the French EU version.
It has 2 connections, one is upstreams and one is downstreams the throttle valve.
This is the original mounting and it works perfect.

Upstreams
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Downstreams
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(Credits to Harry SZ, its his WUR)