Weber 32 /36 should I peanut-ize my stock manifold?

['76mintgrün'02]

I just removed my carb to rebuild and install C.D's jet prescription. The manifold has the stock hole configuration and I have read that there is an advantage to removing the metal between the holes. Should I peanut-ize the manifold?

Tom

[Simeon]

Conventional wisdom is don't peanut just taper/ enlarge the holes to match the throats of the carb. Peanut-ting may slow the speed of the charge too much by increasing the plenum volume below the carb.

I am running mine on the stock manifold, untouched. This is just a phase I am going to grow out of on the way to sidedrafts so I haven't bothered. Too many people say that you can't feel the difference, even if the flow bench tell you it's good. Just drive it and rev it 250 revs higher before you change each gear.

['76mintgrün'02]

Thank you Simeon, I wasn't really looking forward to removing that much material. I think I will go ahead and taper them to match the carburetor and call it good. Your response is much appreciated. Tom

[Guest Anonymous]

One thing you might want to strongly consider as a performance boost. Is a sync link I added one a few weeks ago , and it was an immediate WOW.....Pierce manifold sales them.

ira

['76mintgrün'02]

Heck yea! Thank you Ira, I will definitely order a sync-link kit. I am looking forward to the new jet set-up. I will see what that does and then enjoy the upgrade you've suggested. It's all about noticing the little improvements along the way... though sync-link sounds like a big one. Tom

[Cameron]

If you havent already, replace your stock throttle shaft bushings with bearings. I don't remember exactly who sells them, but search for 32/36 throttle bearings on google and you'll find it. Each kit does one shaft, so order 2. They sync-link puts a lot of extra stress on the throttle shafts, and the bushings will wear much quicker than the bearings.

[jimk]

Conventional wisdom is don't peanut just taper/ enlarge the holes to match the throats of the carb. Peanut-ting may slow the speed of the charge too much by increasing the plenum volume below the carb.

I am running mine on the stock manifold, untouched. This is just a phase I am going to grow out of on the way to sidedrafts so I haven't bothered. Too many people say that you can't feel the difference, even if the flow bench tell you it's good. Just drive it and rev it 250 revs higher before you change each gear.

+1

Finally there is a guy that understands what a sudden enlargment in an air stream does. It also causes fuel to recondense.

Flow bench testing a manifold alone does not tell the whole story. The flow bench test should be done with the carb installed both before and after peanutizing. And if the test aparatus is good enough, the after peanutizing results will be worse because of the sudden enlargement effect on the flow dynamics (it's another fitting loss coefficient in the air stream.).

['76mintgrün'02]

Thank you for the suggestion. I did buy one bearing kit and just installed it on the primary shaft. Shoulda coulda woulda ordered two sets. The secondary shaft feels pretty tight, but I wish I had ordered both sets of bearings while I was at it. I will install a second set if/when I go with the sync-link.

I ground the manifold to match the weber base and cut a gasket to replace the "stock" weber gasket. I cut holes on the new gasket to match the base of the carb, instead of using the one that has an oval shaped cut out; because that essentially connects the primary and secondary ports under the base of the carburetor. The devil is in the details... it sure is fun to fuss over them anyway.

(I wish I knew how to upload photos directly to this posting. It is kind of a pain to ask people to check a photobucket link. Hopefully my description is sufficient).

Tom

[esty]

(I wish I knew how to upload photos directly to this posting. It is kind of a pain to ask people to check a photobucket link.

Tom

highlight & copy the image code, , link next to the pic at photobucket and paste it where you want the image to appear in your forum post

[harry6422]

With all the effort you are putting in to getting your Weber right you might check the accelerator linkage and push rod from the peddle box to the carb, The lag time you fell when step on the gas peddle may not be in the carb but the linkage, below is a link to my post on what I found with my 75 02 and the pull rod I make to solve the problem. Picture is of the wear on the connecting points .

Harry

www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,376280/highlight,/

['76mintgrün'02]

Thank you Esty, I will give that a try.

I noticed that the linkage was worn and filled it in with my TIG welder and filed it back to round. This is just one of the connections that have probably seen some wear... as your photos suggest. Your linkage looks like a good solution and I will inspect the rest of my linkage and probably place an order.

The disconcerting thing is that after my rebuild/re-jet I am unable to turn my idle up. I have turned the screw as far as it will go until the spring is totally compressed. The car is idling low and a bit rough and smells like gas. It drives just fine. Plenty peppy, but idles like crap. Oh well, gives me something to fiddle with tomorrow.

['76mintgrün'02]

I goofed something up when I rebuilt/rejetted my carb. It idles very slowly and smells incredibly rich, with some smoke coming out of the tail pipe. Just for grins I put the old jets in and it still has the same issues. I did modify the base gasket and am wondering if this could be the problem. Here are a couple of photos showing the stock gasket and the one I made.

Is it possible that the carb needs the larger opening under the base?

[Guest Anonymous]

Hi Tom

One thing you may want to consider is cutting down on variables. Changing jets is not an exact science. So, if you change your jet combo, checkout the pros and cons, adjust, get it where you like it. Then move on to another function..

That way it's traceable...

As far as the bigger opening that stock manifold works perfectly, for the 32/36. I personally hogged (peanutized) out my manifold for my 38/38......But for the car I run with 32/36. I have left it stock...

Anyway one thing at a time otherwise we'll just be chasing ourselves (spoken collectively for everybody)..

ira

['76mintgrün'02]

Thank you Ira, I totally agree and tried to take it one step at a time. I adjusted valves and timing and switched to a pertronix unit with new plugs and wires... one at a time, a month or so ago. The car was running well before the rebuild. I finally fixed my odometer and when I checked my mileage I got a miserable 18 mpg. I felt like it was running a little rich and decided it might be time to try C.D's jet prescription. The rebuild was basically a cleaning with new gaskets and jets and shaft bearings. I did measure and adjust the float level (brass) to 1.6" and 2" (from carb top/no gasket), but other that that I did not change anything but the base gasket. I ground the manifold to match the carb base, partially because someone had already chewed it up. Perhaps I should pull it back off and try the stock gasket with the single large hole. It is hard to believe that is the problem though.

Tom