Throttle Linkage Design

[Mandic 0]

Hi,

 

I'm designing throttle linkage for some TBs I'm making and have encountered a problem. If I use circular and linear motion combo (like piston-crank one) I get non linear pull (at least I think so ), so throttles do not open linearly but progressively. Is this normal on TBs which use this sort of linkage combo and if so, how should I set them, is it better to make them open quickly from start or towards the WOT?

 

Thanks

 

Ziga

[brianthemagical 1]

i'd say have it slow at the start for better slow speed and lower throttle (more controled, not just flat out driving i.e. around town) control, assuming you'll use it in such situations.

[Mandic 0]

Jup I also think that, but on the other hand when I looked from side-view section I think there is not so much of a difference as when first thought.

 

I'll wait for some other people inputs regarding this,

 

Cheers

 

Ziga

[welshpug 1,626]

Not sure if this would help at all but do you have the standard Mi16 throttle body still? see what kind of radius that has on the cam wheel?

[Mandic 0]

Well yes, radius ie. cable pull (how long) is not the question here, I have already measured that, the problem is, that I'm using similar design to Jenvey, so cam wheel is pulling a lever which is connected to throttle lever and by being so it creates non linear opening, ie. the degree of opening is not linear with cam rotation. I just wanna now how much this really matters.

 

Cheers

 

Ziga

[welshpug 1,626]

ah I think i see what you mean now, this is similar to the arrangement on the 2.0 Engine

[Dream Weaver 2]

Progressive opening with the slow opening near to closed throttle would be ideal.

 

This would allow you to set off nice and easy from a junction, but still be fine on WOT.

[M3Evo 0]

Definately slow to start ramping up to quick approaching full throttle.

 

Guess you're directly driving the spindles Ziga?

 

Prefer a big thick actuator bar myself with a progressive linkage coming off that, although it does mean that the throttle adjustments need to be taken care of at the spindle which can be a fiddle.

 

That said, the last two adjustment systems I've come up with have worked pretty well, even if one is a bit fiddly.

 

Please don't rely on friction to drive anything in your design. If a throttle jams shut it can cause big problems!

[Mandic 0]

Well I kinda managed to get it all working now, and I also 3D printed the thing (only for one runner due to the costs) so I know what to change, but all in all it is ok.

 

I made a mistake at injector holder, it needs to be reangled for 3° but everything else seems spot on.

 

Hope it will be ready soon.

 

Btw, what do You mean by "friction to drive"?

 

Thanks for inputs,

 

Cheers

 

Ziga

[M3Evo 0]

I tried making the arms which move the spindles so that they clamped onto the spindle.

 

This was fine for months until one particularly frenzied gear change where one throttle got stuck shut and as a result held the remaining five wide open!

 

I've since learned my lesson and make adjusters so that they don't rely on friction to move anything and instead have pins running through the spindles so that they'd have to shear for my nasty experience to be repeated.

 

You got any piccies of your 3D print?

Edited January 25, 2007 by M3Evo

[Rik 0]

I'd like some piccys of the whole set-up if possible please?

 

Throttle linkage is something i've gotta tackle in the nr. future.

 

Rik

[Mandic 0]

I tried making the arms which move the spindles so that they clamped onto the spindle.

 

This was fine for months until one particularly frenzied gear change where one throttle got stuck shut and as a result held the remaining five wide open!

 

I've since learned my lesson and make adjusters so that they don't rely on friction to move anything and instead have pins running through the spindles so that they'd have to shear for my nasty experience to be repeated.

 

But dont Jenvey use this system as well?

 

 

 

You got any piccies of your 3D print?

 

 

Here u go...

 

 

 

Just one runner and in one piece, not like the end product.

 

I kinda missed the location pin of 0.5mm, will need to sort that too,

 

Cheers

 

Ziga

[Mandic 0]

I'd like some piccys of the whole set-up if possible please?

 

Throttle linkage is something i've gotta tackle in the nr. future.

 

Rik

 

Well this is basic layout of the design, not finished, but this is how it is going to look like (roughly)

 

Note that only runner #3 is currently connected to linkage,

 

 

I'm slowly progressing, first I only make things to work, then I make them better sometime just stare at them to get an idea how to make it better and last part are cosmetic changes. So again this is not the final version of the linkage design, at this stage I just managed to get it all working properly.

 

 

Cheers

 

Ziga

Edited January 25, 2007 by Mandic

[M3Evo 0]

Can the linkage drawn really move the throttles through a large enough angle?

[Mandic 0]

Jup, it can move it for about 130°

 

I only need it to move the thing for 81°

[Mandic 0]

OK, another thing,

 

When one presses accelerator pedal to its maximum (WOT), then the butterflies on TB should be fully open and the "limiter" on the linkage should hit some barrier which determines WOT (same goes for IDLE).

 

Now, if accelerator pedal doesnt have limiter so its maximum position is determined by floor carpet, then this carpet can be further compressed if one presses harder on the pedal.

 

In this case there is quite a force present on that "limiter" on linkage.

 

Now, do cars (205) have solid limiter on pedal or do I need to make something in my design which will prevent that from happening?

 

Thanks

 

Ziga

Edited January 28, 2007 by Mandic

[jackherer 543]

Now, do cars (205) have solid limiter on pedal or do I need to make something in my design which will prevent that from happening?

 

Theres nothing on the pedal to stop it, the throttle body does it all.

[Mandic 0]

Thought so...BX doesnt have it either.

 

Cheers

 

Ziga

[Ryan 99]

Theres nothing on the pedal to stop it, the throttle body does it all.

 

There is a spring-loaded thing where the throttle cable goes through the bulkhead that takes up and extra movement in the pedal.

[Mandic 0]

Aha, so there is, superb! nice to know.

 

Do You happen to know how much force can there be applied before it comes into action?

 

Thanks!!!

 

Ziga

[Mandic 0]

One thing...

 

When having throttle plate just at the head entry(lets say 1 inch away) is it better to have it positioned vertically instead of horizontally?

 

As the throttle will cut the flow in upped and lower part if horizontally, where if positioned vertically it cuts flow on left and right part, just like the valves are positioned.

 

What's Your oppinion?

 

Cheers

 

Ziga

[Rik 0]

Could one not just buy the jenvey throttle linkage kit and fit that? with a little modding of course!

 

Rik