Fixing DBW throttle lag/response

[efnfast]

The most disappointing part of my Viper has always been the throttle lag - heads/cam/headers/exhaust/tune never felt like 700tq - and I always felt if I'd test driven it before I bought it I'd never have bought it because of that poor response.

The Gen5 guys were raving about the TKO DBW adjuster so I installed it today
https://driveviper.com/forums/threads/24971-Any-Fix-Yet-for-Gen-V-Lazy-Throttle-Off-Idle
https://tkomotorsports.com/product/2008-2017-pro-competition-viper-adjustable-max-throttle-response/

This is a-w-e-s-o-m-e

Set around 30-40% all of the lag is gone and it drives like cable throttle - instant response, feels like 700tq, etc.

This is how the car should have come from the factory.

If you have an Gen4 and hate the throttle lag/response, buy the TKO unit .... it's plug and play, 5 minutes to install, and a-w-e-s-o-m-e-n-e-s-s. Literally the best mod I've done to my Viper. :monkeyleft:

[Steve M]

Agreed. Installed mine earlier this year when the weather was still garbage:

https://i.ibb.co/kg3mHqk/TKO-Bracket.jpg

I've been very pleased with this purchase, and love that you can go from mild to wild with just the turn of a knob.

[13COBRA]

Agreed. I love mine as well. Huge improvement!

[Baked]

Do you guys know what the difference is between the Pro and the quick track version?

[Steve M]

Do you guys know what the difference is between the Pro and the quick track version?

I think it is just the bracket...the pro version is intended for a permanent install (hence the bracket you see in my pic above), and the quick track version is intended to be quickly installed/uninstalled as needed. I don't like the thought of stuff flopping around near my gas pedal, so I went with the pro version, simply because I wanted the bracket. I'm sure you can do something sufficient with industrial strength velcro if the thought of drilling into your trans tunnel doesn't appeal to you.

[13COBRA]

Correct Steve.

The bracket makes it more permanent. That's what I have as well.

[efnfast]

I think it is just the bracket...the pro version is intended for a permanent install (hence the bracket you see in my pic above), and the quick track version is intended to be quickly installed/uninstalled as needed. I don't like the thought of stuff flopping around near my gas pedal, so I went with the pro version, simply because I wanted the bracket. I'm sure you can do something sufficient with industrial strength velcro if the thought of drilling into your trans tunnel doesn't appeal to you.

I wasn't certain if there was anything behind the tunnel (I have bad luck finding things that shouldn't be in certain places when blindly drilling) so I used the industrial velcro stickies that came with it to mount the bracket to the tunnel, lol

[Steve M]

I wasn't certain if there was anything behind the tunnel (I have bad luck finding things that shouldn't be in certain places when blindly drilling) so I used the industrial velcro stickies that came with it to mount the bracket to the tunnel, lol

I think I wore about a 1/4" off my teeth from gritting them so hard while drilling, and I wasn't going at it blind either - the car was up in the air on jack stands, so I was crawling around and looking at every possible thing I could encounter. Thankfully, it turned out just fine, but man I had that drill going slow, and with very little pressure.

[IndyRon]

What's the consensus on this? Devices like this in the past have just increased the scaling/ramping of the throttle but did nothing for the actual delay between pushing the pedal and engine response. Is this device different?

[Steve M]

What's the consensus on this? Devices like this in the past have just increased the scaling/ramping of the throttle but did nothing for the actual delay between pushing the pedal and engine response. Is this device different?

I still think some of that exists, at least at reasonable levels that are safe to drive around on. It is still a vast improvement over what it was though.

[efnfast]

I've got mine set around 30-40% and I don't notice any delay ... I'm also using Venom ECU, not sure if that's improved over stock or not.

I took it out for a more extended drive today and am 110% satisfied with the purchase - this is how the car should drive from the factory.

[VIPER BAZ UK]

Thought the Dick Winkles tune ironed this out or is this another alternative??

[13COBRA]

Thought the Dick Winkles tune ironed this out or is this another alternative??

I'd say it corrects most of it...but the TKO unit takes care of the rest.

I have both on mine, had the tune first...then when you put the TKO unit on it's a world of difference.

[VIPER BAZ UK]

I'd say it corrects most of it...but the TKO unit takes care of the rest.

I have both on mine, had the tune first...then when you put the TKO unit on it's a world of difference.


Thank you,, guess ill go shopping again

[13COBRA]

Thank you,, guess ill go shopping again

You won't regret it, promise.

[Angleiron]

So if this any better than the Arrow performance PCM? My stock throttle had lag, but after switching to the performance PCM all of the throttle lag went away. I know what is being talked about is the cheaper option.

[Steve M]

If you are happy with your throttle response, then this product isn't for you. It certainly doesn't replace a tune since all it does is alter the throttle response, but it can be added on top of one (including the Mopar PCM, Mopar PCM with Arrow Reflash, or HPTuners) if you need/want more. It is also plug and play, and as such is completely reversible. It can also be dialed on the fly using their included adjustment knob.

[Steve-Indy]

I will direct my question (implied suggestion) to Steve M who knows/understands more about this area than I will ever know.

I am wondering why all of the seat of the pants validations of this product aren't backed by objective data recordings of said throttle response improvement ?? While I am not doubting the product itself, it would be easy to present the change in response times up front...which would encourage more product utilization if so documented. Just a thought.

[Steve M]

Good point...let me think about how best to capture that. I can certainly feel it (especially if you start messing with the knob going down the road), but I can't put numbers to it.

At the end of the day, (I think) it does nothing more than cause the throttle bodies to open more over the first part of the pedal travel. You could theoretically achieve the same results by just pushing the gas pedal harder at all times. There is definitely a subjective aspect to this mod that can't be ignored, and I know it isn't all in my head, but I guess I don't really know what they did. It at least doesn't trip any DTCs or throw the car into limp mode, so that's nice.

[Steve-Indy]

Thanks Steve...I know that one could make this very complex. The question is, when and where does the lag occur...i.e. gas pedal position sensor to throttle body sensor?..actuator motor? Or, PCM delay? Etc., etc.

We are talking milliseconds here...might have been fun to see the action on a laptop...like we did with the early wiTECH setup where a whole spreadsheet would dance with a blip of the go pedal.

The good news is that folks seem very happy with a fairly low cost modification.

[Steve M]

I can make the data dance, I just need to find a semi-controlled way to gather it that doesn't skew the results, and then figure out how to display it that makes sense to anyone looking at it. I won't promise a timeline, but I will see what I can do.

[Steve-Indy]

Not trying to make work for you...I actually thought themanufacturer might jump in at some point with some numbers.

[Steve M]

It'd be a good mental exercise for me...it never hurts to dust off some brain cells every once in a while.

[IndyRon]

I'd be willing to bet that the car has at least 200-300msec (almost 1/3 of a second) delay between stabbing the throttle and engine response. I also have the mopar PCM and that makes no difference. If driving even just slightly aggressive, you almost have to power shift the car to get power application with subsequent gear changes. I actually have trained myself to apply throttle before releasing the clutch to ensure power comes on immediately after clutch engagement.

[efnfast]

I'd be willing to bet that the car has at least 200-300msec (almost 1/3 of a second) delay between stabbing the throttle and engine response. I also have the mopar PCM and that makes no difference. If driving even just slightly aggressive, you almost have to power shift the car to get power application with subsequent gear changes. I actually have trained myself to apply throttle before releasing the clutch to ensure power comes on immediately after clutch engagement.

I'd agree - I never felt there was a situation where that lag wasn't present. Supposedly the venom ECU is improved over stock, but if it is I'd hate to see what stock is like.

The TKO DBW adjuster definitely fixed that though ... putting it on 100% is just fvcken LOL, but at 30% it makes the car respond like it should have from the factory (crisp, no lag, instant response).

Being able to adjust it on the fly is fantastic because the first drive I was wondering if it was in my head - turned it off and the laggy POS response was immediately back.

[Steve M]

What's the consensus on this? Devices like this in the past have just increased the scaling/ramping of the throttle but did nothing for the actual delay between pushing the pedal and engine response. Is this device different?

Circling back to this comment: I did some testing and data logging to see what, if any, effect the TKO unit has on the actual delay between pushing the pedal and engine response.

Bottom line: it doesn't. Doesn't matter if you have it set a 0% or 100%, that lag between pushing the pedal and the engine actually doing something does not change.

What it does is simply amplify the throttle signal - it just reduces the amount of pedal travel it takes to get to 100% throttle.

But it does help with one specific thing, and that is heel-toe downshifting. I've always had a hard time rev matching with the Viper, largely because I just never seem to be able to get a solid enough blip on the gas pedal. Your throttle blip just does more with the TKO unit.

The downside that I've found is that it increases the chances of what I'd call pilot induced oscillation, especially at settings higher than 50%. I had once instance recently where I went to roll into the throttle in 2nd gear, and I ended up losing traction. I immediately let off the throttle to regain traction, which jerked me forward a little bit, and then I tried leaning back into it, only to have it happen again. This went on for a few times before I finally just aborted so I could regroup. It's just something you have to be aware of. It takes about 1-2 drives to get used to the extra sensitivity, but you can still run into situations where you might not want that extra sensitivity.

My $0.02. It does make the car more fun to drive, but you can achieve the same thing by just pressing the gas pedal harder if you want to save some cash. Maybe see if you can try before you buy.

[Steve-Indy]

Most interesting, Steve...as usual, THANKS for your effort and explanation !! Post purchase, seat-of-the-pants testimonials don't do it for me at this point.

I was wondering just why no specific time/response data was offered in the product info that I saw...unless I just missed finding it.

That said, "fun" is good !!

It will be interesting to see what others have to say.

[Steve M]

Nothing like some good ol' choice-supportive bias!

But data don't lie. Neither did the GoPro video I used to capture the response at different settings.

[Steve-Indy]

Do you see an "easy" way to map/graph pedal position sensor's output signal response and throttle position sensor's output signal along with throttle bottle blade activation response ?

[Steve M]

So I can log it, graph it, and play it back real-time easy enough; the problem is that I can't get the data at a fine enough time resolution to be useful. I tasked the logging software to poll for each of the parameters shown below every 20ms, but the PCM just doesn't report the data to the bus that often for each, which makes interpreting the data much harder.

The picture below should be fairly self explanatory, but in case it is not:

Red = Engine RPMs (my idle is set to 925 RPM)
Green = Manifold Absolute Pressure (displayed in kPa)
Orange = Gas/Accelerator Pedal Position (displayed as a %)
Blue = Throttle Blade Position (displayed as a %) - the blades stay cracked around 12.5% to maintain my desired engine RPMs
The vertical white line marks the time stamp; instantaneous values are displayed for each parameter logged on the left.

https://i.ibb.co/KLBWCVw/HPT-Log-Screen-Cap.png

You can look at the events and their associated time stamps many different ways. For example, with the TKO unit set to 0% (picture above):

1. Time between the first recorded gas pedal input (orange) and the first recorded change in the throttle blades (blue) = 70ms
2. Time between the peak gas pedal input (orange) and the peak throttle blade position (blue) = 77ms
3. Time between the peak gas pedal input (orange) and the peak MAP reading (green) = 130ms
4. Time between the peak gas pedal input (orange) and the peak RPM reading (red) = 475ms
5. Time between the peak MAP reading (green) and the peak RPM reading (red) = 348ms

So of all those numbers, number 4 (peak gas pedal input to peak RPM reading) is probably the closest to what is actually happening...about a half second delay. Again, that's with the TKO unit turned completely off.

Here's another screen cap of the data, this time with the TKO unit set to 50%:

https://i.ibb.co/cKBs1xB/HPT-Log-Screen-Cap-TKO-at-50-Percent.png

At first glance, it shows that the throttle blades (blue) were moving before I hit the gas pedal (orange). I don't think this thing is omniscient, so clearly the PCM was a little delayed in its reporting of the gas pedal position. I was trying to keep my blips about the same as far as my foot went, but as you can see, a blip now equates to 100% pedal input at least briefly (I was not putting the pedal to the floor).

Looking at the same differences as above:

1. Time between the first recorded gas pedal input (orange) and the first recorded change in the throttle blades (blue) = -19ms
2. Time between the peak gas pedal input (orange) and the peak throttle blade position (blue) = 21ms
3. Time between the peak gas pedal input (orange) and the peak MAP reading (green) = 200ms
4. Time between the peak gas pedal input (orange) and the peak RPM reading (red) = 495ms
5. Time between the peak MAP reading (green) and the peak RPM reading (red) = 293ms

Again, #4 is probably the closest number to what is really going on. I looked at many other data points, and regardless of the setting on the TKO device, the time difference between the peak gas pedal input (orange) and the peak RPM reading (red) was around 450-500ms.

I'm not sure that's what you were looking for, but that's what I have. Well, that and a poorly done video looking at my hairy leg as I push the gas pedal for what you see above.

[Steve-Indy]

Fantastic, Steve...and, yes, that is what I was after. I thought about asking for the rpm, but that adds another delay...though it definitely is what I think folks would want to see as an end point.

I was also hoping for a better time resolution...but suspected that this system is just too slow.

I KNEW you would capture this someway...and you certainly have succeeded !

Many thanks !!


Many thanks for the write up.

[Loud]

Where are you guys installing the dial? Hopefully somewhere out of sight?

[Steve M]

Center console on mine.

[efnfast]

Given 1/2 went down and 4 went up I'm not sure you can reach any conclusion?

In any event, I'm satisfied with my purchase. I absolutely hated the throttle response before and now it drives perfectly fine.

10/10 would buy again w/o question

[13COBRA]

Where are you guys installing the dial? Hopefully somewhere out of sight?

I put mine above the ignition on the steering wheel column.

[Steve M]

Given 1/2 went down and 4 went up I'm not sure you can reach any conclusion?

In any event, I'm satisfied with my purchase. I absolutely hated the throttle response before and now it drives perfectly fine.

10/10 would buy again w/o question

You are also only looking at 2 of the 25 different data points available in that log, and I never posted the video recording those 25 data points that shows me pushing the gas pedal, and recording the sound of the exhaust. You would not want to draw any firm conclusions based on only 2 data points - they were simply used to illustrate the challenges in logging this data from the OBD-II port, which doesn't report the data out with enough fidelity to see what is really going on, at least not down to the 10s of milliseconds that you'd really need.

As I already stated above, you can't put concrete numbers to it, but the data does allow you to see trends. The overarching theme is that the time difference between me pushing the gas pedal at idle and the engine responding (what I would call "lag") does not change for any given setting on the TKO unit. This is also backed up by the video I took. It does increase the magnitude of the gas pedal inputs, which also corresponds to an increased throttle blade angle, a higher peak RPM, and a larger change in the intake manifold pressure. Those are all expected outcomes for what this thing actually does.

IndyRon and Steve-Indy both asked the same, very specific question: does the TKO unit alter the lag between pushing the pedal at idle and the engine actually responding to that input? The answer to that question is a resounding no. That is fundamentally a PCM calibration issue, and this device does not alter that calibration.

Does it make the car feel more responsive when just going down the road? The answer to that is most definitely yes. Some folks have said it feels like the car has 100 more horsepower. That's because you are essentially asking the engine to deliver more power for a given pedal input. You can achieve the same result by just pressing the gas pedal harder all the time, but this has a subjective feel to it that makes it seem like the car is more "responsive".

[TrackAire]

Steve M,

Thanks for reporting...my butt dyno found the same results with my different brand of throttle enhancer. My concern is not throttle response but the stupid lag. It freaking drives me crazy and truly one of the only things I don't like about my Viper. Years ago I installed a Sprint Booster throttle enhancer with three push button settings (off, mild, extreme). It really did nothing to improve the throttle lag, only increase the throttle opening speed over a smaller gas pedal travel area. So the throttle was faster after the lag portion of the throttle travel had occurred. I'm afraid that every other throttle enhancing system is going to be the same....it's just going to speed up the throttle once it is engaged but not get rid of the lag and dead pedal travel. I don't really need that as under load my foot is faster than the engine can rev anyway. The lag makes heel toe downshifting suck....and I don't feel having an enhanced throttle really helps me for heel toe anyway.

Here is one of the mildly dangerous aspects of the throttle "enhancer" when on the track. On my unit, if set in the more extreme setting you have to be careful when taking a larger radius corner at constant throttle and at the cars limit of traction. If the car hits a bump and your foot moves just a bit, it can cause too much rpm surge and you can spin the rear tires causing you to possibly spin out. I keep mine in the off or mild position depending the track surface.

[Steve M]

Here is one of the mildly dangerous aspects of the throttle "enhancer" when on the track. On my unit, if set in the more extreme setting you have to be careful when taking a larger radius corner at constant throttle and at the cars limit of traction. If the car hits a bump and your foot moves just a bit, it can cause too much rpm surge and you can spin the rear tires causing you to possibly spin out. I keep mine in the off or mild position depending the track surface.

Yes...I've had this happen on the street, and I did not like it. It will be off the next time I take it to the drag strip.

I think one thing people also don't realize is that the throttle blades open at a pre-specified rate. For example, if you go WOT at 2,000 RPMs, the throttle blades don't immediately open all the way. They open like 60-70%, and then proceed to slowly open the rest of the way as the revs climb. You can change this with HPTuners to an extent without triggering limp mode, but it does absolutely nothing to gain power. Again, this device does nothing to affect that.