Full Throttle!

[paulrockliffe]

I've got a 2006 Focus 1.6, it's the 100hp rather than the 125hp version. I've also got a bluetooth ODB2 thingy and Torque on my phone.

Apparently sticking my foot flat to the floor only opens the throttle 80%. Can't find anything about this on the google, so wondering if anyone knows about this?

Am I a remap short of having 125 ponies, or is there a physical difference between the two 1.6 engines? I can't come up with any other reasons to explain why my throttle doesn't open fully.

Ta.

[G600]

Remove some pipe work so you can see the valve in the throttle body and see if it opens all the way?

[buggalugs]

If it's throttle by wire on that car you might find that you only get 100% throttle at high revs, at lower revs you may get more torque at part throttle.

[M Powered]

It's most likely that "Torque" has the wrong transfer function for the OBD PID.

There are numerous PID's for throttle positions (and that's without looking at the manufacturer specific ones.

[davepoth]

I'd not be surprised if the difference is only software - it's cheaper than having distinct parts.

[anonymous-user]

buggalugs said:

If it's throttle by wire on that car you might find that you only get 100% throttle at high revs, at lower revs you may get more torque at part throttle.

No. no you don't.


WOT is WOT at any engine speed. However the geometric position of WOT does change with speed. At low airflows (low rpm) a throttle sized to be a small restriction at peak power rpm, will be unchoked at part throttle (ie it does not need to open to the full 90deg to the direction of air flow).

So take say 2000rpm, here for example, 60deg open my be enough to increase the intake manifold pressure to baro, further increases in angle does not increase BMEP any further. The term "effective wide open throttle" is used to deffine the angle to which the throttle may open to produce maximum bmep at at given engine rpm.


So, why don't we just let the throttle open to 100% everywhere, when their is no torque deficit to doing so? Well, you can blame "torque based" EMS systems for that. They rely on the throttle to control airflow to control torque, so if the transmission (or worse the stability control!) requests a "torque down event" having a massive dead zone in throttle plate movement before BMEP is actually cut is not good (huge non-linearity in control issues).

So, the EMS will be calibrated to only open the throttle plate to effective WOT rather than geometrical WOT (at peak power rpm they are the same value)

However, two things should be noted:
1) generally they the engine isn't running, the throttle will revert to just a "pedal follower" system (rather than controlling airflow/torque). So putting you foot on the accel pedal should open the throttle the whole way.
2) Some engines do use a limited throttle position to effectively create a "low power" model in the line up(for marketing reasons). On these you never get geometrical WOT. It's cheaper for development to just do one engine spec/calibration, fully validte that, then just limit the throttle angle to create the low power model. (no h/w changes (or cal changes except the max throttle pos value))

[paulrockliffe]

Wow, cheers, that's really interesting. From what I remember I had 80% from 2000 rpm to 6000 rpm, but I will investigate further bearing in mind what you've said.

It sounds like my engine is restricted in software as you'd expect to need the full opening before 6k rpm on a max of 8k rpm. Does that sound reasonable?

However, if that was the case I'd expect google to easily corroborate the hypothesis. I can't find much comment for my car anywhere.

Will certainly investigate Torque for errors before I start pulling hoses off.

Thanks!

[JonnyVTEC]

MINI and Rover did the same to differentiate power outputs on the same engine.

[Effortless]

JonnyVTEC said:

MINI and Rover did the same to differentiate power outputs on the same engine.

Wot 'e said ^

Anyone know the engine differences between a Mini One and a Mini Cooper??

Yup, the Mini One has a throttle that opens to 80%...

And that's it...

Cheers,
Effortless

[paulrockliffe]

Aye, but what about me Focus, that's the question?!?

[4key]

I have the obd torque chinese plug in thingy on my audi that I bought for reading other sensors. It gives 100% throttle when the engine isnt running, but takes time to give 100% when on the move. It is quite obvious that there is atleast a second delay which I put down to the bluetooth connectivity, If its showing 100% when you just have the ignition on but the engine off I would suggest that youre problem is more to do with the reading youre getting than anything to do with the car.

[paulrockliffe]

I get 0% with the engine off, 18% on idle then it seems to match well with my foot position, except it tops out at 80%. There's no obvious problem with the data feed, but I'm reading up on Torque now.

[4key]

With the ignition on and the engine off it doesnt read any signal? Funky. The people who commented before me are probably right then, and I have learnt another peice of random information to store inside my head.

[paulrockliffe]

currybum said:

paulrockliffe said:

Aye, but what about me Focus, that's the question?!?

The 100ps version had a fixed cam head. The the 125PS version has twin independent variable cams.... Different engine, different exhaust.

Dreams crushed.

[4key]

currybum said:

paulrockliffe said:

Aye, but what about me Focus, that's the question?!?

The 100ps version had a fixed cam head. The the 125PS version has twin independent variable cams.... Different engine, different exhaust.

Just out of interest, would that justify the 80% throttle?

[buggalugs]

Max_Torque said:

buggalugs said:

If it's throttle by wire on that car you might find that you only get 100% throttle at high revs, at lower revs you may get more torque at part throttle.

No. no you don't.


WOT is WOT at any engine speed. However the geometric position of WOT does change with speed. At low airflows (low rpm) a throttle sized to be a small restriction at peak power rpm, will be unchoked at part throttle (ie it does not need to open to the full 90deg to the direction of air flow).

So take say 2000rpm, here for example, 60deg open my be enough to increase the intake manifold pressure to baro, further increases in angle does not increase BMEP any further. The term "effective wide open throttle" is used to deffine the angle to which the throttle may open to produce maximum bmep at at given engine rpm.


So, why don't we just let the throttle open to 100% everywhere, when their is no torque deficit to doing so? Well, you can blame "torque based" EMS systems for that. They rely on the throttle to control airflow to control torque, so if the transmission (or worse the stability control!) requests a "torque down event" having a massive dead zone in throttle plate movement before BMEP is actually cut is not good (huge non-linearity in control issu

That's interesting thanks. I noticed in most mechanical throttle cars that beyond a certain point of throttle at lower revs there was no increase in torque, and if anything the engine went flatter as you went WOT and pulled slightly better if you back off to that point again. Perhaps there was another explanation for this, or my arse-dyno was out :-)

[davepoth]

buggalugs said:

That's interesting thanks. I noticed in most mechanical throttle cars that beyond a certain point of throttle at lower revs there was no increase in torque, and if anything the engine went flatter as you went WOT and pulled slightly better if you back off to that point again. Perhaps there was another explanation for this, or my arse-dyno was out :-)

Going a step back to carbed engines, this is the reason why over-carbing is bad. The engine can only suck a certain amount of air per cycle, and there needs to be a certain amount of airflow through the intake for the air and fuel to mix properly.

On an engine with really massive carbs the airflow at low revs doesn't mix the air and fuel properly, and so it runs like a bag of crap at low revs.