[TachItUp]

My girlfriend, being the wonderful person she is, bought me an OBD scanner for Valentine's day.

I plugged it in and was playing around with Torque, and noticed that the throttle was only opening 75% according to the app. The app's website stated that some cars might not open the throttle all of the way, but I assumed it would still be more than 3/4. Is this normal in an 05 Elise?

 

[sturgeongeneral]

That seems low. Have you physically looked at the butterfly to see how much it is opening?

 

[Nessal]

I believe it's normal on these cars.

 

[Zoomby_U]

That's normal for an Elise/Exige ... you need to get a tune to utilize the other 25% ie. Koldfire or BOE Torque. Lotus purposely reduced the opening to control the HP output ... that's pretty much the main difference between the Exige S220, S240 and S260.

Cheers,
Zoomby_U

 

[TachItUp]

That seems low. Have you physically looked at the butterfly to see how much it is opening?

Nope, unfortunately. I store the car elsewhere during the week so I can't take a look at it for another few days. I was hoping that it was just a quirk of the lotus ECU.

Hopefully the neighbors don't mind me opening the throttle all the way manually to see what the scanner reads

 

[Nessal]

That's normal for an Elise/Exige ... you need to get a tune to utilize the other 25% ie. Koldfire or BOE Torque. Lotus purposely reduced the opening to control the HP output ... that's pretty much the main difference between the Exige S220, S240 and S260.

Cheers,
Zoomby_U

Is that really the change from all those different models? I thought it would at least be a smaller pulley or something.

 

[ithurtus]

Wow how about that, learn something new everyday

The real reason is to make up for the deficient glove-box-tray. Every time you WOT with a tune you relocate everything inside the tray to the passenger seat / wife's face.

It's a feature, "Lotus saving your marriages at every stop light"

 

[MConte05]

That's normal for an Elise/Exige ... you need to get a tune to utilize the other 25% ie. Koldfire or BOE Torque. Lotus purposely reduced the opening to control the HP output ... that's pretty much the main difference between the Exige S220, S240 and S260.

Cheers,
Zoomby_U

Except the 2005 is a drive by cable, not drive by wire? :shrug:

 

[MotoGeek]

I have no actual knowledge, but I wonder if it's because that's all the air the engine is capable of ingesting, so there's no need to open it further. If this is true, then opening it further would just contribute to wasted pedal travel.

 

[oldmansan]

I have no actual knowledge, but I wonder if it's because that's all the air the engine is capable of ingesting, so there's no need to open it further. If this is true, then opening it further would just contribute to wasted pedal travel.

Negative.

San

 

[Nessal]

I have no actual knowledge, but I wonder if it's because that's all the air the engine is capable of ingesting, so there's no need to open it further. If this is true, then opening it further would just contribute to wasted pedal travel.

Don't think that is true or else turbos and superchargers would be worthless if the engine is only capable of ingesting that fixed amount of air.

 

[Nessal]

Don't feel too bad. I had a 2011 Camaro SS and my OBD2 scanner shows up at 70% max TB opening as well. Maybe just a coincidence.

 

[tommyc]

I manually checked and adjusted my 05 so it opens fully. The cable throttle 05's have a tps. 06's up throttle is controlled by ecu.


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[JamesD]

I have gotten into this with the control engineers at my work, They say you do not need to open a butterfly valve more than around 70 percent since the flow barely increases any more between 70% and 100% opening. Most of this is primarily related to the shaft that holds the butterfly valve being thicker than the valve and hence is the restriction and that means there is no real reason to open to 100% since it is just wasted effort ( think about it rotating)

While I agree with them in theory (I still say that I want my valves at least 85% open) I still believe there is flow effects that will benefit from it opening more, such as less turbulence.

O, and rule of thumb for butterfly valves, you will get 80% of your flow at 20% of your valve opening...

I have had an 05 and an 06 Elise, I firmly believe the 05 is faster with the throttle cable setup!

 

[komiko]

love my throttle cable.

 

[jds62f]

That's normal for an Elise/Exige ... you need to get a tune to utilize the other 25% ie. Koldfire or BOE Torque. Lotus purposely reduced the opening to control the HP output ... that's pretty much the main difference between the Exige S220, S240 and S260.

Cheers,
Zoomby_U

This is only half true, the 240's and better have bigger fuel injectors, not sure if there are other little things they may have. to supply proper fuel/air for the increased power

 

[TachItUp]

So today I stopped by the garage and did a back to back test.

Using the accelerator pedal, the car opened the throttle 78%. Opening the throttle via hand at the engine yielded a whopping 82%. The first couple of cm of pedal travel yields nothing, so maybe I can adjust it for better response and find that extra 4%.

 

[Vulcan Grey]

I have seen that as well, a friend's '05 Elise showed a ~70% throttle opening with an ELM OBDII scan tool. I spoke with the developer of the Torque app on the Android platform and he said "Yes, that's the actual throttle value, not the pedal value - it's filtered by the ECU. the 11% will be idle (at 0% your engine stalls ) I am surprised it only opens to 70% at full throttle though on a Lotus though this isn't uncommon, again this is just the ECU filtering what you want to do."

 

[ageshelin]

re: Throttle opening

If the above is not people trying to joke around, I am going to leave this forum.

The throttle opening is measured by the Throttle Position Sensor. It is a rotary resistor.

The tune does not really depend on the TPS too much. It is used to sense a rapid throttle opening (as when you mash the pedal) to enrich the mixture and for certain other parameter that do not kick in if the throttle is open beyond idle.

There are 2 potential causes of the reading being off:

1. The throttle is not opening 100%. This is not good. A partially closed throttle will create a lot of turbulence in the intake tract. Check the throttle visually to make sure it opens all the way. Otherwise, the throttle body is broken.

2. The TPS is not calibrated and is reading wrong. Follow the calibration procedure in the manual. Your car will run better....

It could be a combination of 1 and 2. It could be that OBDII software is not reading correctly.

If this thread is designed to be a joke then you all got me.

Anton

 

[cyow5]

Anton, I work in the professional racing industry - not all throttles go to 100%. Some guys actually pull the throttle back at certain rpms on egas cars. Sometimes it seems like a result of airflow because some manifolds have a bit of a curve to the airflow, so 85% actually puts the blade parallel to the airstream, other times they have no idea why it makes more power but it just does. I'll talk with a CFD buddy to see it he can explain it


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