Throttle response

[j-ten-ner]

46 minutes ago, Grumpy Bear said:

Did you know that a 'butterfly' valves flow rate is not proportional to blade angle?  This delay gives a more linear throttle response. It also does something else. It makes throttle angle more speed appropriate. In the graph note that about 80% of the valves flow rate is obtained at 50% blade angle. If the throttle body is sized for X CID @ WOT then 50% angle @ 25% rpm results in  weak manifold vacuum. The fuel tables are constructed on volumetric efficiency based on the manifold absolute pressure, not the barometric pressure vs CID. If you look at these tables you might be surprised to find that VE's of 98% are possible at 1,000 rpm and 20% TPS. In simpler terms the VE tables are the ratio of cylinder density to manifold density and not theoretical swept volume standard atmospheric density vs barometric density. 

 

Throttle response isn't how fast the throttle blade reaches WOT. It's a mechanical time constant that is often limited by things like rotating mass than air supply. 

 

 

That's why you've got better acceleration when you push the pedal in a steady motion, than to hammer the paddle to the floor.
At least with carbureted engines.

 

so long

j-ten-ner

[Rob Okray]

On 2/10/2018 at 6:21 AM, muddkatt said:

They do it so that the drive train  is not subjected to instant full load conditions. Keeps the amount of parts failures down for warranty jobs, and the truck will get 0.01 MPG better fuel mileage to meet CAFE requirements.

Not that I bought it to beat on, but being a truck designed for more than moving people, I would hope the driveline could handle some wide open throttle passing maneuvers on occasion. 

So how do you undo the voodoo that they do?

[Rob Okray]

On 2/10/2018 at 12:06 PM, Grumpy Bear said:

Did you know that a 'butterfly' valves flow rate is not proportional to blade angle?  This delay gives a more linear throttle response. It also does something else. It makes throttle angle more speed appropriate. In the graph note that about 80% of the valves flow rate is obtained at 50% blade angle. If the throttle body is sized for X CID @ WOT then 50% angle @ 25% rpm results in  weak manifold vacuum. The fuel tables are constructed on volumetric efficiency based on the manifold absolute pressure, not the barometric pressure vs CID. If you look at these tables you might be surprised to find that VE's of 98% are possible at 1,000 rpm and 20% TPS. In simpler terms the VE tables are the ratio of cylinder density to manifold density and not theoretical swept volume standard atmospheric density vs barometric density. 

 

Throttle response isn't how fast the throttle blade reaches WOT. It's a mechanical time constant that is often limited by things like rotating mass than air supply. 

 

 

Assuming a stock configuration perhaps, but for those who have modified, the delay may not be needed or desired.

[muddkatt]

10 minutes ago, Rob Okray said:

So how do you undo the voodoo that they do?

Get a tune from Blackbear, Diablo, or another competent tuner.

[Rob Okray]

I have an idea I'm going to play around with when it gets warmer. May have to ditch the delay.

[truckguy82]

On 2/9/2018 at 8:28 PM, Swerd said:

Hi, I recently got my first Silverado. It’s a 2015 5.3 CC Z71. I really like it but the throttle response is awful. Seems to have plenty of power once you get on it, but from a stop when I hit the gas it is so slow to respond. Is this normal? The engine dose not stumbles or misfire, just slow to respond. Also at lower speeds it seems like the transmission has a hard time deciding what gear to be in. Between the slow throttle response, V4 mode, and confused transmission bumper to bumper traffic is painful. I am coming from a car. Do I need a trip to the service department or is it something I just need to get used too! 

 

Thanks

 

 

Tune it.

 

If someone asked me to guess the power output of my 6.2 and I had no idea what it was stock or how much a tune normally effects an NA engine.

my guess pre tune- i’d say 400hp 380ftlb

post tune - 450hp - 500ftlbs

 

 

Stock:

0-60 before tune =6.1 seconds (no idea how the mags got 5.6-5.7)

0-60 post tune = 5.0 seconds

 

The gains are mostly from releasing the engine from it’s factory tuning nannies, not increased power.

 

[swathdiver]

Did anyone mention Torque Management?  This is what makes the motor feel like a dog off the line.  Maybe these new ones don't have it like the previous.  Anyhow, get a BlackBear tune and never look back.

[SWOYER]

I would say blackbear, diablew or any tuner should be fine. 

 

The only difference is the vehicle they use to get the tune into your ecu, the diablo is cheaper and probably easier to use, the autocal is probably a better product for long term. But i decided on the diablew because of the top notch customer service, reviews and feedback on this and other forums. I would probably be just as happy with the black bear or other. If you plan on doing bolt ons, I'd say definately diablew, if your going to go deeper I would feel more comfortable with an autocal, or hptuners and a dyno but thats just me. 

[Aaron1085]

The damn stock 5.3 just feels ... slow.


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[Ozer]

I went with cheaper tune option and got the TruXP tuner for $200 from autoanything. It has few pre loaded tunes, can change bunch of parameters and so on but one thing that may help you is increasing the throttle response from 2%- 20%. I have it at 20% and can def tell the difference with the 87 octane tune. With 91+ octane (ran 93) i could feel the truck so much more nimble and ready to launch at demand.

I went back to 87 because i dont need that for a daily truck but it was fun. Try it out

[Aaron1085]

A $200 tuner? Interesting .... can you unplug it when you go into the dealer?


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[Ozer]

27 minutes ago, Aaron1085 said:

A $200 tuner? Interesting .... can you unplug it when you go into the dealer?


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Its an actual tuner that changes the files in the ECM and re writes them. So before a dealer visit you will need to load the stock tune back on, Im at 102k miles so no worry about that for me.

This is the one:  http://www.autoanything.com/performance-chips/truxp-xtune-plus-performance-tuner

 

If all you want is throttle response increase then look at SprintBooster. Thats all it does, changes the input signal so you get full throttle a lot quicker.

I have it on my BMW X5 diesel and in race mode the throttle is super sensitive. I keep it in street mode and its perfect. I occasionally turn it off and get reminded real quick why i got it lol