Lotus Elan

Mangoletsi Throttle System

PostPost by: 1owner69Elan » Mon Jan 18, 2021 2:25 am

I have been using a TTR throttle cable setup as below since I recently installed a SAS Weber head that replaced my original Stromberg head. The TTR setup has been working reasonably well. The spring is rather strong, taking a fair amount of pedal pressure to move the throttle. There was also some "lost action" (free play) in the linkage - but overall it worked.
IMG_3538 (1).jpeg and
TTR linkage above

But, recently I found that the cable was binding with a grinding noise. The throttle had become increasingly difficult to push. Rather than replace the cable or troubleshoot the issue I thought I might try another approach. I had earlier been intrigued by the Mangoletsi throttle linkage. What appealed to me was the various adjustments available to tune the throttle action to one's preference. However, I was earlier scared off of the Mangoletsi approach as the only info I could find regarding installation in an Elan indicated that it required removing material from the inlet runner web, something I was loath to do on a brand new head. The photo below shows the area where the head material was filed down in the earlier post.
mangoletsi-side.jpg and
Head filed down for clearance above

Even with this concern I thought I would give the Mangoletsi a try, figuring there had to be some other solution besides filing the head.

I purchased the Mangoletsi in the UK. I couldn't find a US based supplier. When I trial fitted the Mangoletsi I found that the interference of the inter-carb linkage (throttle lever and balance lever) was much worse than expected. It would require removing something like at least 1/4" from the web - out of the question. The area circled below is where the interference occurs.
IMG_6646.jpeg and


After much thought and fiddling I figured out a solution which was to rotate the intercarb linkage away from the web by 180 degrees to a position where there was free space. This required modifying the existing (right hand throttle lever as well as the supplied ball pin (left hand) throttle lever and then superimposing them on the rightmost carb. The modifications to the two levers are shown in the pictures below.
Mangoletsi 1.jpg and
Modification to Mangoletsi lever above
mangoletsi 2.jpg and
Modification to original lever above

Summary of steps with mods as depicted in above pictures:
1. Remove the connecting tab on the Msngoletsi supplied throttle lever, only retaining the throttle stop and ball pin lever.
2. Remove the lever and throttle stop on the original right hand lever, and the standoff washer. Thus, retaining only the tab to connect to the balance lever on other carb. Relieve this interconnecting throttle tab (as shown) to not foul the ball jointed Mangoletsi connector on the right carb.
3. Rotate the existing right hand throttle lever 180 degrees and place on top of the modified left hand lever with the ball pin. Secure both levers together with the nut and tab washer.
4. Rotate by 180 degrees the newly supplied right hand balance lever and secure it on the left carb with the nut and tab washer, engaging the connection tab from the front carb. Adjust the balance to synch the two carbs.

Some pictures of the completed assembly:
IMG_6621.jpeg and


IMG_6646 (1).jpeg and
IMG_6628.jpeg and



What this accomplishes is that the inter-carb connection is rotated by 180 degrees and completely clear of the web on the head. So no clearance problems, and no modification of the head.

So how does the new Mangoletsi throttle feel?

1. The pedal pressure is much, much less than the TTR. At first, it took a little while to adjust and I considered putting in stronger springs. I had already adjusted the mechanism for maximum spring tension. But, now I like the easily depressed pedal and don't feel the need for stronger springs.

2. The overall action is very, very smooth, direct and responsive. No lost action in the linkage. Utterly smooth cable travel.

3. The overall effect is a dramatic sense of readily available power. With the TTR the pedal action was a bit more binary (on/off). (Maybe also because of the "frictional drag" in the system, as implemented on my car.) The Mangoletsi throttle is more controllable but also more sensitive.
The car feels so much more powerful, delivering a smooth and continuous transition to all of its horsepower and torque with little pedal effort. The car feels faster and quicker.

To reiterate, the Mangoletsi will not work on an Elan (Weber head) straight out of the box. Not a plug and play solution. But, with some judicious fettling of the parts it can be made to work and not require untoward "mods" to the head.



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Attachments
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Last edited by 1owner69Elan on Mon Jan 18, 2021 4:23 pm, edited 1 time in total.
'69 Elan S4 SE
Street 181 BHP
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PostPost by: nmauduit » Mon Jan 18, 2021 8:50 am

thank you for your detailed post : I suppose the SAS new casting if beefier in the webbing area, so that the fettling to fit the Mangoletsi as designed would be more difficult. I have fitted one on an OEM head (better bonnet clearance was my initial motivation), and filing was minimal (I did it mostly to ensure some extra clearance in the linkage area towards the end of travel for the set screw, I could also have shortened the screw). Regarding friction and tension in the linkage, I suppose the more the sooner something will wear out : maybe in autocross where everything jumps everywhere one would need to brace a lot and still have some feeling in the pedal, but other than that I too prefer the most sensitive pedal I can get.
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PostPost by: TBG » Mon Jan 18, 2021 9:45 am

I have built a system that is so simple it is laughable! Tried some expensive alternatives and gave up and went my own way. If you can bend and cut bits of stainless to shape - bobs your uncle. Gives you a very variable spring rate - choose your hole - has a very short throttle cable run - and is light and simple - oh, and cheap!!

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PostPost by: LaikaTheDog » Mon Jan 18, 2021 1:55 pm

I had a lovely mechanism that worked perfectly well until my tuner pointed out I didn't have WOT...
I built my own and it...worked, but was ugly

So I went with a sytec and it worked first time. I liked it so much I fitted it to my Alfa Romeo twincam too... And had the same problem as the OP, the mechanism fouled the castings of the inlet manifold, I searched for the correct levers and ended up rotating a standard "lotus" Weber lever by 180degrees and it works perfectly,
so I now have two Weber setups on the sytec mechanism, and if you wire brush the alloy parts you can make them look old/retro
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PostPost by: baileyman » Mon Jan 18, 2021 3:47 pm

I have a Sytec also, and can attest to hours of frustration with it. My conclusion is the thing is a bodge that somehow made it into production. So I have been re-bodging it for months.

My initial concern was the change in cable direction through the sweep forced the cable to rub the cable out end of the housing, no matter how adjusted. (No self-respecting bicycle mechanic would ever approach such a design.) I bent the mounting plate to the middle of the sweep angle, which helped but did not cure. I determined what I needed was a small rod end to fit the cable housing end to so it could swivel through the sweep and "point" in the direction of cable travel.

Further, I determined I could reduce the sweep angle by moving the cable end further from the lever.

And I, too, was unhappy with the digital nature of lever operation. So I though what I needed was some kind of wheel to replace the lever with, one that would operate over 90 degrees. I wanted slow take up and fast finish, so it would need some kind of eccentricity.

Then I noticed I, too, could not get WOT! That was the final straw, so I took it out and began re-bodging.

A bit of stainless allowed me to extend the mounting point of a small rod end a few inches and now the cable will track anything without rubbing. Taking the operating lever out I scribed an Euler curve to match my desires and cut a plate to do that. Now the throttle works half as fast to start and twice as fast to finish. And I fashioned a bicycle style cable pinch, no kinks there.

I figure with labor this re-bodged Sytec is worth about $30,000. I do like the stainless plate idea above and I am still attracted by the Mangoletsi solution. But this one now works and I have other things to do.

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