Weber DCOE 45 - Will bolt on velocity stacks work?

[JeffB240z]

I've gone through the forums and cant seem to find a bottom line answer to this. I have Weber DCOE 45's on my 240 and I just purchased some new stacks (pictured in red). These stacks are the bolt-on style and do not slide into the carb, like some that I am seeing (also pictured).

1. Will my bolt-on stacks work with no issues?

2. I  read that the "slide-in" type stacks help hold the venturi in place, is this true?

3. I also read that the "slide-in" type stacks do something with the choke plate, is that true?

Thanks,

Jeff

[grannyknot]

Can you post a couple of pics of the front of your carbs, looking down the throat? We need to see your configuration. The slide in type stacks can be used to butt up against the venturi but there are also short sleeves that will do that but don't interfere with a bolt on stack. Make sure that the inside dia. of the bolt on stack is the same dia. as the opening of the carb body. You don't want a lip there, you want a smooth transition between the bolt on stack and the carb.

[JeffB240z]

On 9/8/2016 at 6:05 PM, grannyknot said:

Can you post a couple of pics of the front of your carbs, looking down the throat? We need to see your configuration. The slide in type stacks can be used to butt up against the venturi but there are also short sleeves that will do that but don't interfere with a bolt on stack. Make sure that the inside dia. of the bolt on stack is the same dia. as the opening of the carb body. You don't want a lip there, you want a smooth transition between the bolt on stack and the carb.

Just got the filters and backing plates off. Here are the pictures of what it looks like. There doesn't seem to be any sort of sleeves in there now, but not exactly sure what that would look like if there was. I held the new stacks in place and the transition seems like it's going to be smooth and the diameter feels perfect. There is that small lip just inside the edge of the throat though, will that noticeably interfere with the air flow?

[grannyknot]

I might be mistaken but those look like kind where the venturi, chokes and butterfly are installed from the rear, so if that lip you mention is sticking up into the air flow then it will interrupt the laminar structure of the flow. Now does that mean less power, maybe, probably not but if you can smooth it out you will get the most from the stacks.   Those air filters you have won't fit anymore but there are stainless steel mesh caps or foam sock filters that can be used instead.

[Mike W]

So the short answer is yes they should work but with a few caveats.

I run 40 DCOE's not 45's and so I don't know the differences with the main venturis and how they are clocked into place and also held in place.  In my early Italian made 40's  the main venturis were installed from the front and were only held in place with the stacks that slid in between the venturi and carb body.  On the later Spanish made 40's, which are the ones I run right now, the main venturis are clocked into place with a key and slot and are held in place with a set screw on the bottom of the carb, so I don't believe they rely on the stacks to hold them in place.

In addition, I have always had a fuel "weep" out of the front of the carbs whereby I would get a very small amount of fuel that appeared to leak from the slot that the venturis slide into.  I messed with float levels etc to try and cure this and never got to the point where it was reduced to zero.

So with the bolt on stacks, I now use a large o-ring thats approximately the size of the main venturi outside diameter and sandwich the o-ring between the flange of the stack and the inner part of the carb opening, which now covers up that slot, and fuel weeping solved.  Don't even get a drop coming out from there not and I get the extra benefit of the o-ring holding the main venturi in place.  I have some pictures of my install included here but unfortunately I do not have a picture of the 0-ring installation.  I can get that for you later as well as the o-ring dimensions if that would help you out further.

Also I use the mesh filters from Bills B Racing and they have worked out great.  They look fantastic and do an admirable job of filtering as well.

Finally, I purchased my stacks, which are really well made by the way, from Borla Induction as it was the only place I could find them to fit Webers and with the length that I wanted.  They actually had to make them as a special for me as they did not have stock at the time.  I'm curious to understand where you sourced yours as they also look very nicely made.

Hope that helps.

Mike.

 

[JeffB240z]

Thank you guys for this information on the stacks. I got them installed on Friday, still need to put on the heat shield from Datsun Spirit, but here is a picture of them. One thing that they definitely do is make everything else look real dirty!

Matt, good point out on the weeping, I will keep an eye on that and see if I experience the same. Thanks for sharing the info on the mesh screens, I will be ordering up a set of those this week.

The stacks that I have are from a company in AU called RHD Engineering. They actually sell a few sets on ebay, which is where I ordered them through and they came in less than a week.

http://racehead.com.au/products-page/velocity-stacks-and-spacers/velocity-stack-ram-tube-trumpet/

I ordered the 76mm length. They seem to be decent quality. Two piece (all aluminum) design, which I like because you can easily trim down the trumpet to whatever length you need.

 

 

 

[ksechler]

Mike:

Where'd you get those screens?

[JeffB240z]

9 minutes ago, ksechler said:

Mike:

Where'd you get those screens?

I dont know which ones they are specifically but this is the website for the screens.

http://www.bbrfilters.com/

 

 

[Mike W]

Yes I purchased the screens from Bill at BBR Filters.  He is the founder and owner and knows his stuff.  All I had to do was to tell him the stacks I was purchasing along with my carb set up and he knew exactly what I needed.  Great product and they do a much better job of filtering than you may think.  Bill has quite a bit of data on that front as well.

 

Mike.