Franck's BP emulsion tubes

[SENC]

Mazzers - yes but where do you buy them? D

A link to his group is in the first post in this thread. He sells through a "WebStore", and I'm pretty sure that link is on the sidedraft central group site, though it may be embedded in one if the topic discussions.

I'll try to grab some side-by-side photos when I'm playing with it this weekend, but what you need to know if you decide to try his bits is that Keith is constantly experimenting, tweaking and further developing to try to make more predictable and efficient air/fuel mix and flow.

The BP tubes were specifically designed (recently) as an improvement over the prior NF (non-frothing) tubes for small chokes after he discovered that with smaller chokes while the NF ran well they did not respond to air/dry jets changes. Most of his recent work has been to try to make the BP tubes work well for medium and large chokes, in hopes of creating a single tube design.

I've tried the NF and BP tubes and found both an improvement over the standard weber e-tubes - better and more consistent through the rpm range, though admittedly by feel and I have not dyno'd or tested AFR.

[TBG]

Thanks so much for your help. I have emailed him and am awaiting a reply. Seems a good idea.

[ericbushby]

Thanks Henry, I had not seen that either. Much better lead than mine.
I wondered why Rob appeared to be unhelpful, sorry Rob.
Eric in Burnley

[SENC]

Keith's NF tube on the left, Weber F16 on the right. Keith's is made in 2 pieces in order to lift the fuel jet off the bottom of the well.

[TBG]

I thought it might be interesting to recount my experience with Keith Franks NF tubes in my Elan S3 S/E. I was impressed with the information on the Sidedraft website and took the plunge and bought them. I fitted them and was very disappointed. Rough running no oomph and so on. It turned out that I had not read the instructions properly!! Anyway KF was very patient and steered me in the right direction and soon I was experiencing a LOT more power but still issues with rough running at steady throttle and jerkiness at times. I have a really good chum who is an engineer in the classic car business and between us we fiddled with jet sizes and have now hacked all the problems. The car now goes, like I said before somewhere, like a greased weasel, pulls from 1000rpm in top if I am gentle and accelerates like an electrified cheetah!!

Remember I am the silly old fool who had a 3:1 CWP made instead of faffing around throwing money at a 5 speed.

I thought I would give you my final set up which is working wonderfully.

1700cc engine with QED 420 cams, Distributor Doctor electric ignition and Webers jetted as follows.

34mm chokes - Main jets 150, Air correctors 185 and Idle jets 50F8

It may not align with some of the charts I have seen but it works. Happy Bunny now and cannot wait to get back to the French Alps and chase motorbikes.

FF has been endlessly supportive via email and I heartily recommend his NF tubes but be prepared to fiddle about a bit. D

[gjz30075]

Not Famous Franks, but it is Keith Franck's emulsion tubes.

[TBG]

Oh I thought that they were one and the same. Sorry Franks. Of course I have been dealing with Keith. Good chap.
Have modified my previous post.

[mwhitaker]

Hello- thought I would share my experience with Keith Franck's VP(venturi pump) tubes which replace the emulsion tubes in the main jet assembly of side draft 40/45 Webers and are an evolution of his VF firecracker tubes with holes instead of a slot.
For background my 69 Elan was a mess when I bought it 4 yrs ago, running poorly, difficult to start, uneven idle, popping on overrun, etc. The motor is 1700 cc (rebuild 20 yrs ago, forged pistons, electronic ignition-Crane, 45DCOE Webers with 36 mm chokes)-originally made 160 hp on dyno. at 6300 rpm. C type single groove reground cams-specs unknown. Standard Weber head but I don't know if larger valves were used.

Most everything was off-incorrect cold ht range plugs with narrow gap, timing ,idle mixture, weak idle jet for 45DCOE, air corrector jet of 200, main jet of 130, carb balance, etc. Breather tube from head to airbox venting to atmosphere. Pancake air filters with no airbox.
With trial and error/ refurb , my current setup has BP6ES plugs with .032 gap, idle mixture screws 1 3/4 out, new modified airbox to eliminate taper over the #4 carb throat, hi flow K & N filter, new dizzy cap, wire, rotor with distrib service, static timing at 12 degrees BTDC. Carb settings- 65F8 idle jet- rich to overcome limitations of 45 Weber progression holes, 130 main jet, 170 air corrector, F16 e tube and 45 accelerator pump jet. Carbs balanced with 4.5 kg/h on all 4 throats at idle. New mechanical fuel pump .
The car has run well, quite strongly at mid upper RPM level but kinda weak down low although even idle and no off idle stumble thanks to the rich idle jet. Oh, all new carb o rings, spacers, thackerys at proper tightness too so no leaks. Plugs are nice dark brown, no fouling , and no smoke out the back. Relatively even exhaust manifold temps of 480-520 F across the board. I haven't measure A/F ratio or manifold settings-old school here.

Rather than decrease choke size to 33-34mm in part because I don't want to remove the carbs again for awhile after replacing block to breather tube, thought I would try Keith's tubes. Have been following his sidedraft Weber blog for a awhile and was most impressed with his white paper on Weber tuning. I would say these tubes have been a marked improvement at the low-mid range level and pull hard nicely up top-the car feels like it has more torque so i don't feel the need to reduce choke size for now.
The tubes are $25 each and you need 4. Be careful and follow the instruction diagram for proper tube positioning/clocking. Best part is you don't need to replace the other wet/dry jets unless you are having issues with them. I haven't used any of Keith's other products but everything seems well thought out/engineered and of high quality. Definitely a more efficient step up from the emulsion tubes. You may find them worth a try as I have.

Cheers, Mark Whitaker
69 Elan S4DHC
45/8396

[mwhitaker]

Sorry- forgot to add that there are small, medium, and large VP tubes depending on your aux choke size.
Small- 30-32mm
Medium-34-36mm
Large-38-40mm

Have fun-Mark

[RichardHawkins]

Mark,

I too have been following Keith’s work, as my restoration is incomplete, I have just put Keith’s work into the interesting but not yet category. One of the many things that I don’t understand is how to gain access to Keith’s “White Paper”, can you advise me?

Richard Hawkins

[mwhitaker]

Hi Richard- if you go to the first post in this thread from Henry, you will see the "sidedraft@vintagetechnology" site address to click on. Once there, look in the left side column under "Home" and you will find a "files" choice. If you click on that it will give you a list of topics including the "white paper" which is the last one on the list. Hope this helps.

Cheers-Mark

[gjz30075]

Mark, I don't see a 'files' choice here; I am signed in, too. What am I missing?

[mwhitaker]

Hey Greg- I have no idea if you are signed in why the other choices are missing. However I just did an internet search via google using " keith franck-white paper on Weber tuning" and the PDF popped up as first choice so give that a go.
Cheers, Mark

[gjz30075]

Thanks Mark!

[mwhitaker]

No problem, Greg- enjoy, it is a nice , well organized read.