Motorised throttle body

[RAd28]

yeah, i'm starting to like the idea... i just wonder how it would go retrofitting... obviously you'd need sensors (depeding on what you intend to do with it) and a computer to control it. but you get rid of the ugly throttle cable (it's only ugly when there's an alternative ) and it'd make a whole bunch of stuff simple (idle etc). i just wonder whether the response is programmed in slow in most applications, or whether it's a proper short fall of the system.

Just looking at the image Madmont posted, is the wiring for he TB on the near side (4 wires) or on the far side (6 wires?)? ie just how big is the motor?

[madmont]

Here are a couple more pictures

[wilbo666]

Some 2JZGTE VVTi ones...

Stolen from this thread... http://www.supraforums.com.au/forum/...ad.php?t=45926





Cheers
Wilbo

[wa5]

Whilst I can see why manufacturers would go this way, I just cant see why someone would fit this to an older (carburettored ) car...
I am not afraid of technology, but why anybody would go for a more complicated (and I am guessing heavier) system just for looks (and they really arent that petite... and what you save on a throttle cable you lose on bulky wiring) eludes me....
OK I can see the benefits if you are including traction control etc.... but if not.. why bother..?

Now, ABS on an older car, that would be useful

[Moppitt]

Got reduction gearing :O

That been the case, would these run as an open or closed loop system? closed would seemingly make sense We have the pedal sensors *2, the tps and the motor, would the ecu compare the pedal position to the tps result?

As to retrofitting this system, how would you go about the computer control of this system? Would something like megasquirt be able to do this or would it involve an aftermarket ecu with fbw control (expensive?)?

[RAd28]

why bother..?

I've got no intentions of retrofitting to a carby setup vehicle, but i have an idea i'm playing with which is already far fetched, so adding FBW couldn't be that much more... besides... Dreaming costs nothing, entertains plenty, and in todays society has zero carbon footprint... Question then is... Why WOULDN'T you?

must say though, it's a suprisingly bulky unit... wonder if you could cut out the crap and stick with motor -> butterfly....

[wa5]

Old saying, if it aint broke, dont fix it...


However I would be interested in the end result if someone tries this...

[RAd28]

it's not called TOYMODS for nothing :-)

[mrshin]

On a carb? From a sensibility point of view it is rediculous, but for the hell of it, why not?

[Mos]

That been the case, would these run as an open or closed loop system? closed would seemingly make sense We have the pedal sensors *2, the tps and the motor, would the ecu compare the pedal position to the tps result?

It's closed loop, but not in the way [that I think] you think.
The APS (accelerator position sensor) is purely a "demand" device. The computer can decide how much throttle to open - this part of it does not have to be closed loop as such.

The TPS tells the computer how much the throttle is open, and based on how much the computer *wanted* to open the throttle, it will adjust the current to the motor to result in the *wanted* position. This part must be closed loop otherwise no feedback control exists.

Now if the computer should decide that the TPS should continually follow the APS, then you have two closed-loop loops. One is the normal motor adjusting to result in the desired TPS value, and the second is that the desired TPS value will be continually adjusted based on the APS value.

As to retrofitting this system, how would you go about the computer control of this system? Would something like megasquirt be able to do this or would it involve an aftermarket ecu with fbw control (expensive?)?

The earlier systems (as pictured) fit inline with the throttle cable, so if you used a corresponding ECU it will control the throttle. I used the IS200 1G-FE ECU to control an LS400 1UZ-FE throttle body and without any other inputs it operates as expected. (In case you're wondering I didn't just plug it in - I checked all the voltage ranges for all the sensors and currents for both motors and both clutches - while these were extremely close other throttle bodies might have different ranges and not be interchangeable).
I have heard rumours that some aftermarket ECUs can control the throttle bodies but nothing concrete. In its most simple form (with no feedback) you could produce a PWM output based on the APS value but such a set up would have a limited slew rate and wouldn't necessarily follow the APS on fast transitions.

adding FBW couldn't be that much more... Question then is... Why WOULDN'T you?

To be completely honest unless it's already fitted to the engine I can't think of a single sensible reason to retrofit. Toyota traction control is extremely rudimentary at best (your foot does a much better job), and cruise control can be achieved with a lot less effort on cable throttle bodies.
Now if the factory traction control let me dump the clutch at 7000rpm with no wheelspin it would be a different story...

must say though, it's a suprisingly bulky unit... wonder if you could cut out the crap and stick with motor -> butterfly....

Errr?? all it has in it is absolutely all that it needs...? I don't get how you could take *any* crap out and still have it work [reliably]?
Edit2: Upon further thought, there is exactly ZERO chance that a cable throttle body, WITH traction control butterfly and motor, AND idle speed motor with associated hardware will weigh less than a corresponding electronic throttle body. And if you add a cable cruise control setup the sums go into significant weight saving.

Mos.

[Moppitt]

Cheers Mos - gotta spread the love-
You were right about the way I was thinking of closed loop. Interestingly the APS output is often termed 'driver demand' by manufacturers diagnostic computers. *Moppitt wonders why he didnt think of that earlier*

Cleaver solution with the 1g ecu to control the 1u throttle :O

By the By, it looks like the Haltech '350z' is a standalone that controls fbw throttles. Its not a generic "Wire into anything that needs an aftermarket ecu" ecu yet, but its progress.

[andrew_mx83]

Do you think it is possible that at low rpm and high load you can actually get more power with partial throttle opening due to increased air velocity. Drive by wire may actually help in this case.

A bit like the old SU carbies or the twin throat carbs with vacuum secondaries that would only open up after you get a decent amount of vacuum.

snap the throttle wide open from idle/low speed and the gas speed thru the head drops to (almost) nothing causing the engine to bog down....not enough vac left to suck the air/fuel properly.
motors with bigger valves/ports/TB's etc tend to suffer worse than standard or smaller ones.... a restricted intake helps the low rpm gas speed at the expense of top end flow.


to accelerate briskly i pause at about a third throttle first until the engine clears its throat and is generating some serious vaccuum before i open it right up.


my understanding of FBW was that it did this for you, basically meant mum and dad drivers could just mash the loud pedal and still go fast?