Accelerator Cable for Dual Carbs ? Options

[Darren C]

Ok Aaron,

Lets look at what I wrote and what you replied….

1, To be frank... You have no idea what you are talking about.

You are perfectly entitled to your opinion I respect that, so let me answer.

2. The throttle levers stay on and are "pinned" to the pulleys.

I wrote, you take off the weber levers with a QUESTION mark as I was NOT 100% certain.
I wrote that in my opinion it was over engineered. Pinning pulleys to levers is over engineering. Like the bracketry to the carbs it's lazy engineering to have all those slotted holes and even more lazy to fit a pulley to a spindle instead of a lever, then leave the lever on and pin a pulley to that. The lever is only held on with one nut for heavens sake. Your point has totally confirmed my observation that its bad engineering.

3, The cable connecting the master to the slave is ideal as it doesn't change with heat or expansion. Once the slack is taken out you are more or less done.

A cable between master and slave I wrote “you’re totally reliant upon Carb B’s return spring to keep the cable tension” this is ok until a spring breaks. It is not fail safe like a solid rod linkage.

4, All the standard springs for the carbs stay in place, so you are no better or worse than with a linkage. If one carb hangs open with either system you have a potential problem.

We agree believe it or not. This is my point entirely because its a cable between A & B if any carb hangs open or its return spring breaks (carb B) you have a potential problem. Any throttle linkage needs to be intrinsically safe. This is why a fully cable system is not a good idea.


5, This setup is WAY smoother than my PERFECT CB hexbar set up. My balance and feel is perfect with this setup. Something I could never achieve no matter what I did with a hexbar setup.

Again I never said this set up wasn’t smooth, I never said it wasn’t better than the hex set up for smoothness or feel or ease of set up. I said it was worse only in its inability to fail safe as in point 4 that we both agree on. We both know the Hex bar system is poor.

I race the stuff Chris builds and appreciate his engineering greatly. Not a fan boy, just a user.

I understand fully that I’m against fans and friends of Chris or whoever makes whichever linkage. I have constantly maintained that I am not interested in the people behind these linkages, only to point out as an engineer, the areas in which these linkages can be improved for the benefit of all.

Again Arron I respectfully ask those of you who have issues with my observations to take a little time to read into and understand what I’m saying here rather than shoot me down based upon your interpretation of what you think I’m saying.

[ChrisFoley]

If any of the vendors visit this site or if any of you know them, please get them to PM me, I’d be only too pleased to help them develop their products, free of charge.

You're just too smart for the rest of us Darren. (IMG:style_emoticons/default/dry.gif)
However, none of your strongly worded opinion about my linkage kit is based in any semblance of factual (real-world) information.
It's unlikely I'd ever ask for advice (on any subject) from you after reading this thread.
(IMG:style_emoticons/default/KMA.gif)

[somd914]

If anything I'd say the DD with FI has an issue if its got the same heavy pedal feel/resistance as the carb conversion car!

I can say that I converted from D-Jet to dual carbs using the existing cable that was re-routed. My CSP linkage turned out to be somewhat lighter, better throttle feel, and returns faster in comparison to how the D-Jet was, though I'll admit this is a qualitative assesment as I didn't instrument the rig.

I'm not attempting to draw out an argument, just saying what my experience has been.

[Darren C]

If any of the vendors visit this site or if any of you know them, please get them to PM me, I’d be only too pleased to help them develop their products, free of charge.

You're just too smart for the rest of us Darren. (IMG:style_emoticons/default/dry.gif)
However, none of your strongly worded opinion about my linkage kit is based in any semblance of factual (real-world) information.
It's unlikely I'd ever ask for advice (on any subject) from you after reading this thread.
(IMG:style_emoticons/default/KMA.gif)

Hey Chris,

Finally.

Unfortunate everyone before you has muddied the water with what they think my intentions are here and a general consensus has been reached that is incorrect.
I just want to see better products for everyone, no more no less.

When reactions simmer down, have a think again, my doors always open.

Regards
Darren

[rhodyguy]

Muddied the fucking water? Dude, you tore the linkage up! Let us see...."bloody stupid" (tally ho!), "over engineered", "damn right dangerous", next "plain stupid" ( make up your mind!) and then dangerous again. Have you forgotten what you have written? My cable goes thu the tin, with a grommet, where it is supposed to, stays where it's supposed to at the firewall and operates nicely. My last entry on this one. One wonderful thing about the British (IMHO) is you can tell them to fuck off and nobody breaks a sweat. Calling someone a cunt works for both genders and as a general rule is no foul. There you have it....bob's your uncle.

[Darren C]

Muddied the fucking water? Dude, you tore the linkage up! Let us see...."bloody stupid" (tally ho!), "over engineered", "damn right dangerous", next "plain stupid" ( make up your mind!) and then dangerous again. Have you forgotten what you have written? My cable goes thu the tin, with a grommet,where it is supposed to, stay where it's supposed to at the firewall and operates nicely. My last entry on this one. One wonderful thing about the British (IMHO) is you can tell them to fuck off and nobody breaks a sweat. Calling someone a cunt works for both genders. There you have it....bob's your uncle.

Hey Bananaman,

Are you sure you're not my ex wife?

Yes I tore the linkages up. All types in equal measure, no particular favorite.
Every now and then you have to shake the tree to clear the dead wood.
Got to admit it's made a hot topic out of it now.
Maybe that's what's needed to effect change or just make people look at things with a fresh perspective. Either that or just alienate me then....

[rhodyguy]

Ok one more since you have now made personal. As others might attest to, this is where it starts to get interesting. I didn't tell you to FUCK OFF! or call you a CUNT!!!. Simply observations from personal experience. One would presume that learned gentleman as yourself would understand the applications and the differences. Perhaps the contrary?

ZOIKS! "Bananaman". I don't know. I'm crushed.






















Wait for it.
















Nope.












Wait for it.

















Did your ex wife have a penis?

[ThePaintedMan]

You're just too smart for the rest of us Darren. (IMG:style_emoticons/default/dry.gif)
However, none of your strongly worded opinion about my linkage kit is based in any semblance of factual (real-world) information.
It's unlikely I'd ever ask for advice (on any subject) from you after reading this thread.
(IMG:style_emoticons/default/KMA.gif)

(IMG:style_emoticons/default/av-943.gif) That's why I love this guy! ^

I don't have to keep defending Chris' product. It works for me, and that's what I know.

Either order one of Chris' linkages and take the time to truly understand how it works before bashing it, or go back into your shed with your hacksaw and create some more of your product, try to sell it, and let's see who gets more business. Otherwise your argument is invalid. You're trying to help, I get it, but you lack tact and factual knowledge of other systems. Yours is probably great, but unavailable to others. Chris's is for sale, has been tested (works great), and he didn't start off by bashing others.

[Darren C]

Ok one more since you have now made personal. As others might attest to, this is where it starts to get interesting. I didn't tell you to FUCK OFF! or call you a CUNT!!!. Simply observations from personal experience. One would presume that learned gentleman as yourself would understand the applications and the differences. Perhaps the contrary?

ZOIKS! "Bananaman". I don't know. I'm crushed.

Did your ex wife have a penis?

I know you didn't tell me those thing's directly rhodyguy, it's called "baiting me" (particularly the "nope & wait for it". Classic baiting) to add fuel to a fire and intended to make others giggle, snigger, cheer and actually think you did call me directly those things, and maybe to promote or encite someone else to do so directly in their next post. (because no one reads into the intention on the internet, just sees the words which is why we're where we are now on this thread). But I've been around the block, I kinda know you wanted to call me those things anyway and used the observation and experience as a convenient tool to deliver the elephant in the room.

My Bananaman respose is a non offensive word, light hearted reply to you trying to bait me. If you take it as a personal attack to be playfully called Bananaman, you need to lighten up a little and you're letting this thread get to you.
As for my wife having a gentlemans part, she thought she did sometimes. Thinking about it, it would have gone with her moustache though.

Paintedman, I have nothing against any of the folks who make these products.
It seems that if I highlight any issue where they could be improved (whichever way that opinion is expressed on whatever product) the drawbridges are raised and the arrows are fired by their supporters.
I get it.
What I don't get is why everyone has to take this personally when I'm talking about a product not a man, and then get so hot under the collar?
Is it because you don't think I appreciate that the vendors have gotten up of their behinds and invested their time and money in bringing to market a product?
Is it because you think I dont understand how tough that is?
Do you think that I have no appreciation of how many people they've helped out.
Is it because you think I don't realize that (apart from Empi) that they probably haven't made any money out of it?
Do you think I simply don't appreciate everyones gratitude for what they've done?

Trust me I do.

All of this toing and froing is unfortunately detracting from the linkage and cable issues.
There are good points made in this thread that are getting lost in the bun fight.
This is a real shame.

[rhodyguy]

Chum the waters. The sparkling lure flashes. Fish on!!! (IMG:style_emoticons/default/owned.gif) (IMG:style_emoticons/default/blowup.gif)

[Darren C]

You're gonna need a bigger boat.

[jd74914]

​Apologies for sticking my nose in here since I have no real stake in the game but I really felt compelled to comment since Darren is taking so much fire. I'm not going to comment on any of the linkages; they all have positives and negatives ranging from price-point to complexity to robustness. I also know Racer Chris well and consider him a friend. (IMG:style_emoticons/default/smile.gif)

What I really wanted to say is that I can see where Darren is coming from and it seems that most people are getting caught up in the criticism rather than the intent. Maybe his writing is a little harsh, but it's quite difficult to actually read intended tone from forum text. When you spend a lot of time looking at failures you end up being hypercritical which isn't necessarily bad thing. Almost all car parts can use improvement in some manor, though in general older Porsche design is quite good (look at the stress relieved heads of the lower shock bolts, etc.).

It seems that not many people here have sat in a lot of detailed FMEAs. They tend to change your perspective on things a little bit, especially when people who have extensive experience with reliability and failure analysis are in the room. The discussion is really focused around improvements with participants who have less bias due to decreased stake in the game than the designer. Essentially you are 'arm-chair quarterbacking" to increase safety and reliability. In an FMEA you are assessing the design for an impact factor which is based on severity of the failure's effects and frequency of failure.

The problem with aftermarket car parts is that the severity rating can be quite high (death in the extreme), but in general the occurrence rating is unknown. In engineering failure analysis, low occurrences are often measured in mean-time between failures of 10,000 to one million hours, etc. That sample just isn't possible with specialty parts for niche cars.

As far as the throttle actuator discussion here I play (work is only work when it's not fun) a fluidic/thermal controls engineer and am personally a huge fan losing the throttle cable altogether and going DBW since you can tweek the actuation curve, but that's not really in the scope for most induction packages here. (IMG:style_emoticons/default/laugh.gif)

[Darren C]

Thanks jd, much appreciated. I waste a lot of my life in FMEA meetings only to walk out cynical about the rating value, which can, like statistics be manipulated for the goal at hand by the strongest players in the room. However I grant you, it’s a good communication device for getting messages across and translating engineer speak to bean counters.
Fluidic/Thermal controls engineer..great, I love thermodynamics and HSD loops!
What’s interesting is your comment on aftermarket or niche low volume manufacture occurrence rating. At R-R the best jobs are in Bespoke where low volume can mean just 1. We obviously make more than 1 of things, even though only one may be sold. This strategy makes FMEA very interesting. Only last week the first customer Black Edition (very low volume) Wraith’s were finished. These have an interesting wheel design (interesting for a Rolls-Royce that is) because it’s made of carbon fibre. I can’t say too much on the internet, but the development was troublesome in combination with the weight loads that could theoretically be placed on the wheel from the 3 ton car at 155 miles per hour +, versus the designers brief and aesthetic. Suffice to say the whole engineering ethos behind the choice of carbon fibre as a construction material fell to the engineering practicality and safety resulting in a carbon fibre wheel that’s actually heavier than the standard Wraith alloy. This is a good example of what I was trying to express about “all good intention” by the throttle linkage makers.
I know most responses to my posts in this thread have rightly challenged my credibility and experience, and I’ve said a few things to try and substantiate them, but something else that is worthy is my own car collection.
This runs from pre second world war to current cars. I have a collection of finished restored cars (my life’s work) and cars stacking up to be restored. These kinda chart and document the history of car evolution. This evening after work (and working on my 14) I thought I’d share some in relation to linkages which people think I don’t have any experience with.
From Edwardian times throttle linkages have evolved from large heavy solid metal bars, thru dainty rods, on to wire cables and now FBW.
I have cars with all of these examples that I’ve restored. The very early cars were exceptionally crude but very ingeniously and beautifully engineered. Throttles didn’t always start off under your foot, they were on hand wheels (like a steam train), hand pull levers, and attached to the most odd things in the cabin. Foot pedal accelerators started to become the norm very early in the 20th century (although they first appeared before 1900) each car manufacturer had their own idea. What was common however is the ingenious methods to connect their throttles to the carburettor.
For a time even some manufacturers had part throttle on the floor as a pedal, idle throttles on the steering wheel and choke/start throttles on the dash!
Basically 3 sets of mechanical linkages to one single carb, each pulling on a different lever via the most elaborate “watchmakers” engineering. The simplest ball joint would have phosphor bronze cup bushes each side with tension springs inside the ball joint to give fluidic contacts between ball and cup, take up wear over time and be ever reliable. The basic bell cranks were cast in the finest steels, to Victorian aesthetic designs with white metal or bronze bearings, some even incorporating automated oil feed systems built into the car.
Not only were throttles done this way, timing advance was too. In tonights pictures I’ve taken, I chose an early 30’s car from my collection so that you might recognise some basic parts. This is when distributors started to look like what you’d recognise as distributors and so on. In the early days of motoring there were no vacuum advance or centrifugal advance of the ignition timing, so you had to twist the distributor by hand, while driving. Some manufacturers like Bugatti had the distributor poke through the dashboard at you to make it easy to adjust your timing, others created more linkages for you to push and pull or slide when you were driving. Again different manufacturers chose different methods it wasn’t standardised, but all involved mechanical linkage.
Some even back in the 1920’s had ride control (adjustable suspension) via adjustment of oil pressure to the dampers (shocks if you will). Guess what, more linkages around the car.
These are days before hydraulic brakes, so yet more rods and linkages across the chassis with clever mechanical transitions to take into account suspension movement and steering while using brake rods. The car I’ve chosen in the photo actually has another set of rod linkages for a brake servo which works of a dedicated clutch plate on the side of the gearbox at 90 degrees to the motor drive clutch. In certain gears this mechnically engages with the footbrake lever to a collection of additional servo brake rods giving greater mechanical force to the front brake drums.
So all in all this car is linkage-tastic, you might say. And boy was it a challenge to dismantle, restore and set back up as a result. I learnt a hell of a lot on this car alone.
Here’s some of the basic linkage controls on the steering wheel. You can also just see the carb start lever on the dash behind the throttle open position on the wheel.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1463170009.1.jpg)

The way it works is with a set of ever decreasing diameter tubes within tubes all the way down the steering column.
The largest tube is the steering itself which has the worm gear attached in the steering box at the bottom. The other tubes run trough oil seals and bearings to exit out the bottom of the steering box in the engine bay.
These have levers attached that connect to numerous control rod linkages that go off in this case to….the top one turns the distributor for ignition timing, the next one goes to a linkage and bellcrank which actually passes right through the engine block between cylinders 3 & 4 in this straight 6 to reach the throttle lever on the carb. The final link goes off to connect to the 4 dampers one on each axle which stiffen or soften the ride.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1463170009.2.jpg)

There are also two separate rod linkages to this car’s carb that run from the foot accelerator and another from the dashboard start throttle.
All in all you can imagine it’s a real handful to drive this thing.
The luxury of having so many classic cars is that you see and get to work on all sorts of set ups, you see how things evolved and developed (good & bad) and you connect with the people and time in which they were made.
I also like to think that in some way also it allows you to make constructive and experienced comment on things when you have an extraordinary experience and knowledge of the subject matter, its history and development within the market place.

[Scott S]

"I also like to think that in some way also it allows you to make constructive and experienced comment on things"

When is this going to happen?

While it pains me to generalize, this type of thread/exchange is exactly why I am no longer a member of several UK forums, as the tone was becoming the norm far to often.

Tact. try it.

[Darren C]

Its going to "happen" when you don't misinterpret the meaning and make assumptions on my tone Scott. In the same way you quote my sentence and edit off the last half so you lose the true meaning! Great example of how you are selectively reading my words and missing the true intent.

There is obviously some US, Brit differences going on with both our countries communication styles that we're both experiencing here?

I'm communicating as I would on any home site, yet you have highlighted an issue as an American that offends you with our "tone" on several UK sites for some reason that eludes me.

So as I said previously it's maybe a Brit US culture thing?

[rhodyguy]

(IMG:style_emoticons/default/flag.gif) (IMG:style_emoticons/default/brain.gif) (IMG:style_emoticons/default/309.gif)

[Darren C]

Exactly Rhodyguy, thanks.(Is that you cutting your line on this fish?)

So this morning I took a walk down to my garage and took off a few dust covers to carry on with the evolution of the humble throttle cable story.
I pondered a while on which cars to show you that would illustrate changes, and settled on jumping 40 years forwards into the 1960’s.
Solid rod linkages were common on all makes of pre-war cars as I’ve commented on already.
This is ok when your engine is low power and hard mounted in the chassis. Just think of the old vintage car movies where the engine shakes the car and its occupants roughly when idling along.
As things progressed the high end manufacturers did much modification to dynamically balance their engines and included torsional dampers and such like before they conceded to flexible mounting their motors and accepting at idle and on acceleration they’ll move.
This was the Eureka moment that threw the solid throttle linkage from pedals to carburettors into depths of history and the age of the Bowden cable throttle was born.
But just before we make the jump, I’ll show you an example of how engineers who knew the deficiencies of the cables dug their heels in to overcome rocking engines with solid rod throttles.
In this example a Cardan shaft is used with a solid flexible plate coupling at the end it leaves the bulkhead, and a sliding rose ball joint at the end it mounts to the bellhousing.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1463227831.1.jpg)

This allows for a solid accelerator mechanical link to be achieved between the fixed body of the car (and gas pedal mount) and the motor which very cleverly doesn’t pull or push on the throttle itself as the engine is free to rock.
This is then linked in the traditional way with rods and ball joints to another interesting mechanical transition bell crank that incorporates a kick down device in this automatic transmission version.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1463227831.2.jpg)

Finally linking multiple carburettors with finite adjustments. Note the manufacturers choice in weighted self lubricating brass connection blocks that build in a pendulum safety factory to compliment the return springs in a failure mode. Not infallible (nothing is) but boy if you can see and understand the detail and reasoning behind the design you have to admire it.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1463227831.3.jpg)

Obviously this was high end market when it was built and budgets were a little different to the FMCG marketplace of today where even the motorcar is becoming a disposable asset instead of a keeper.
In the mainstream however at this time (I’m still talking 60’s) the norm was a Bowden cable throttle. Cheap and easy solution, and perfectly good when kept in good condition and run & operated correctly. As I’ve commented in previous quotes, KISS, (keep it simple stupid) the cable ticks all these boxes in the right application.

So jumping forward again to the 1970’s where our 914’s live, I chose another of my cars to show a little further throttle evolution relevant to the aftermarket carb conversion of a 914 where this thread has its origin. Having opened a few hoods, this car has a Bowden cable from gas pedal to engine and then the linkage is split to service two sides of the motor.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1463227832.4.jpg)

Again the design of choice is cable to main engine link, then solid link bars & rods to the destination. In this picture it’s worthy to note that the pivot points of the linkage rods are run in ball bearing races, and the tie rod ends have wire locked ball and socket ends to combine and reduce any play in the system between the banks.
All in all it provides as best it can an intrinsically safe and adjustable linkage with devices to remove mechanical wear and friction. I’ve rebuilt this twin cam & the previous V8 and I can tell you again, that they have taught me a great deal.

So why am I rambling on 914 world about my own indulgences?
Sure I’ve owned, built & restored 20+ VW bugs from 1952 thru 78.
8 or 9 VW busses (I loose track)
Numerous Ghia’s, Type III Variants, notchbacks, 412 etc.
Lots of Porsche from 356, 911, 924, 944, 928, 968, 986 (all versions) to Cayenne Turbo and now my first 914 in the Build-Off Challenge.
As much as I love them all, I’m not a one stable guy, I have god knows how many other brand cars, and had so many cars in total over the years I do genuinely have no idea on the figure.
One thing is for sure it’s opened my eyes to how many ways there are (and have been in the past) for an infinite number of manufacturers to re-invent the wheel.

Racer Chris, you wrote…”You're just too smart for the rest of us Darren”

Well; I’ll let others be the judge of that, being smart is a genetic thing (like Rhodyguy being 50% banana) man is only just on the verge of being able to manipulate genetics. In the meantime we are stuck with the cards we’re dealt.
There’s always a yin and yang Chris. My ex-wife would say I could tell her pi to 50 decimal places but I was shit in bed. (Still have kids though, yep someone was foolish enough to let me breed)
Maybe you’re one of those guy’s who’s better in bed than me Chris, who knows, none of us has it both ways and does it really matter anyway when all we end up wanting in life is comfortable shoes and absorbent underwear.

So, the point of this rabble is?

Look at ALL (not just one suppliers) 914 carb linkage kits, cable routes and general engineering quality and decide which one is for you.
I’ve made my opinions (very strongly it seems) known, and out of frustration I made my own linkage (only because I was fortunate enough to be able to do so)

And maybe, just maybe, some of you who’ve walked into this minefield here may have the balls to say “hey I think this product could be better too”

[rhodyguy]

(IMG:style_emoticons/default/pissoff.gif) (IMG:style_emoticons/default/mueba.gif) (IMG:style_emoticons/default/splat.gif)

[Darren C]

You're trouble. I have your card marked Bananaman, I preferred your I'm stupid imogie before you edited it in favour of the fish slap ;-)

[rhodyguy]

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