Carburation choking my engine?

sxuxrxf · Posted: Fri Jul 25, 2014 10:57 am Post subject: Carburation choking my engine?

My engine pulls hard to about 4k rpm and runs out of steam. I'm assuming it's the carbs. Engine is in a '71 Westfalia Bus.

1968cc (74x92 thick-wall)
40x35.5 valves, no port/polish
Web Cam 218 (.460" lift, 280* duration, 242* @ .050")
1.5" heater boxes and header w/large 3 bolt flange and 2" tubing to Dynomax Super Turbo muffler
and...
Kadrons w/32 venturi. I think, 60 idles and 160 mains.

Time for some 40mm IDF's?
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jfats808 · Posted: Fri Jul 25, 2014 11:33 am Post subject:

Mains are huge. Try down jetting it to 140s and try another pull.
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madmike · Posted: Sat Jul 26, 2014 5:10 am Post subject:

Yep get IDF's Cool

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VWCOOL · Posted: Sat Jul 26, 2014 5:28 am Post subject:

I spin one of my engines to 7000rpm with Kaddies, and it's lusty all the way... so the problem isn't with air

But yes as mentioned, 160 is rather moist with the mix!

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135-140 main will work. I also think 60 idles are too big.

The extra fuel is putting out the fire. It will pull much crisper with the leaner jetting.
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sxuxrxf · Posted: Mon Jul 28, 2014 7:40 am Post subject:

A friend dropped off a set of 44 IDF's yesterday! I just need linkage and some downsizing on the venturi and jets.
It looks as though the smallest venturi for the 44's are 32's...will this be ok? Guessing on the jetting...50/52.5 idles, 135/140 mains, 200 airs, f11's?
Recommendations?

I will be wiring up my Innovate AFR meter so I can get it dialed in.

I know the Kadron's will work, but the Webers will be better. I had two 2017 engines with the same cam, heads and exhaust.. One with Kads, the other with IDF's....the Weber engine was much more powerful with minimal fuss, while the Kads required several hours by AJ Simms and larger throttle bodies to still be underwhelming.

Engine specs:
1968cc (74x92 thick-wall)
Short 5.32 rods
40x35.5 valves, no port/polish
Web Cam 218 (.460" lift, 280* duration, 242* @ .050")
1.5" heater boxes and header w/large 3 bolt flange and 2" tubing to Dynomax Super Turbo muffler

'71 Westfalia @ sea level.
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66brm · Posted: Mon Jul 28, 2014 5:05 pm Post subject:

One question, are you running dual valve springs?
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Danwvw · Posted: Mon Jul 28, 2014 5:17 pm Post subject:

You should be able to run the the 32mm venturi's especially with the 40x35 valve heads. What are those heads? Also the Web-Cam 218 is not a high RPM cam. Mine has 30mm venturi's and the Web Cam 163 which is like 8' more duration & a lot less lift and 35.5X32mm valve stockish heads and pulls strong to 4500 RPM but still is there above that. Does it have the short rods?
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sxuxrxf · Posted: Mon Jul 28, 2014 8:14 pm Post subject:

Danwvw · Posted: Tue Jul 29, 2014 3:14 pm Post subject:

I have been thinking about your engine and with so much lift on the cam is should pull strong all the way up to the cam's limit Which should be 5000' ish. So it must be those carbs! I really like the Dellortos but you need to find them used. They have a little more control for a driver. The Web IDF 40's would be what is available new but they are a little bit more aggressive.
Check the Samba Ad's for Dellorto's 36's or Dells they would be the same size as the Web-40's and Probably run a 30mm or 32mm Venturies.
Here is an example of the Dellorto carb's: http://www.thesamba.com/vw/classifieds/detail.php?id=1650099 I may buy these myself for my spare engine!
The manifolds would need to be opened up to port match your heads! Probably involve pulling the heads, Just as well have them cleaned up in the ports 3 angle valve job if needed. I am curious to know how it works out if you do it because your engine is the engine combination I want to try my-self. How fast does your bus go up hills in 4th gear. You know those hills that are steep enough to give it a real work out but not so steep that you must down shift to 3rd gear on! Mine pulls those hills at about 54mph in 4th, But with those heads and your engine you should be pulling them at 65mph? An example would be Crater Lake Hill in Oregon.
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