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Paulyy
Joined: 05 May 2014 Posts: 87 Location: Melbourne
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Posted: Wed Dec 13, 2017 3:10 pm Post subject: Weber dcoe40 install help with fuel system. |
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I’ve got the carbs, I now have the right jetting.
We have dellorto dhla 40s on there running (terribly) with a redline FPR and the stock fuel pump. I have the fpr on the return line so the fuel goes in both carbs then out to the fpr on the return.
Does that sound right?
The dellortos are old and probably jetted wrong as we haven’t touched the jets, we just tried to get the car running with them in the first place. Which it turns on and revs.
So I have the Webers. New. Jetted to the 924 spec. Now I want to put them on and make sure the fueling is right so I don’t break anything.
Thanks. _________________ 924 - Race car project in the works.
http://www.924board.org/viewtopic.php?p=384410#384410
951 - 400whp. |
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Fasteddie313
Joined: 29 Sep 2013 Posts: 2596 Location: MI
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Posted: Thu Dec 14, 2017 6:04 am Post subject: Re: Weber dcoe40 install help with fuel system. |
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Paulyy wrote: |
We have dellorto dhla 40s on there running (terribly) with a redline FPR and the stock fuel pump. I have the fpr on the return line so the fuel goes in both carbs then out to the fpr on the return.
Does that sound right?
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IDK about those carbs in particular but NO..
So you are pretty much trapping max fuel pump pressure in your carbs?
I think you need to so something more like..
Gas tank-fuel pump-Fuel line T-pressure regulator-return line-Fuel line T- Fuel tank
And you need to go..
Pressure side T-carb in-carb out-return side T
I think you only want like 5psi into your carb and then 0psi out of your carb..
I don't know what kind of FPR you are using, ho many ports and what they do, how it's designed to work, or if your carbs are quite different than usual, but it should be something more like this..
Or like this..
Or with a carb return line T back to the return line like I was saying..
Depends on what kind of FPR you are working with but I don't know of any carburetor that wants a system pressure trapped in it like a CIS distributor.. _________________ 80 Turbo - Slightly Modified |
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Fifty50Plus
Joined: 28 Feb 2008 Posts: 1354 Location: Washington DC area
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Posted: Thu Dec 14, 2017 8:10 am Post subject: |
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Like Eddie says for the routing. Solex, Weber and Dellorto carbs don't like more than about 3 1/2 pounds fuel pressure. More like 2 -3 pounds. _________________ 1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car |
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Paulyy
Joined: 05 May 2014 Posts: 87 Location: Melbourne
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Posted: Thu Dec 14, 2017 11:29 am Post subject: |
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The FPR im using is this Redline one,
http://garage.ideola.com/prod-EngineMods.html#weber
1 In and 1 out.
I set it up how you'd set up a normal fuel rail. Fuel goes into the rail, then out of the FPR keeping equal pressure though the rail.
So with carbs, there's no return i assume from those images. Except the last one with a bypass.
I do understand about the 2psi thats needed. _________________ 924 - Race car project in the works.
http://www.924board.org/viewtopic.php?p=384410#384410
951 - 400whp. |
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MikeJinCO
Joined: 08 Jun 2010 Posts: 1228 Location: Maysville, Colorado
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Posted: Fri Dec 15, 2017 1:03 am Post subject: |
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A fuel return line from the regulator isn't required. I use a Holly 12-804 FP regulator. It might be easier to run a return as the difficult part was finding a cap for the existing return line. Finally found one made by Vibrant Performance It is like a 12x1.5 or 14x1.4 pipe cap which is not easy to find in this country. I am going to try to use the standard NA fuel filter when I tested it with a low pressure fuel pump it worked. Again the fittings are hard to find and they came from Vibrant Performance thru Summit Racing. The inlet and outlet are different sizes. _________________ Mike
'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild) |
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Paulyy
Joined: 05 May 2014 Posts: 87 Location: Melbourne
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Posted: Fri Dec 15, 2017 1:15 am Post subject: |
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I got it now plumbed like the 2nd image. and have 2psi to the carbs.
Soon i'll get the webers on. will update. Hopefully they are turn key. _________________ 924 - Race car project in the works.
http://www.924board.org/viewtopic.php?p=384410#384410
951 - 400whp. |
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