I found some old threads searching, but found nothing conclusive.

Is anyone familiar with the tip-in delay on the V6 and manual transmission? Is the solution inside the tables on the tune or something else? I'd like to get the car behaving more predictably. If that's normal for a supercharger to have that much delay, then I guess I'll drive it more like a turbo car.

 

I was able to remove that delay with a throttle programmer. https://jagmadness.com/start-shoppin...t_id=300015698

 

Just to clarify, this removed the extremely perceivable delay after a braking event, then getting back on throttle? Thanks!

 

Correct me if I'm wrong, but isn't this just what the "engine" setting in the Dynamic setup does?

(I always run mine in Normal anyway since I'm already tuned well past the torque rating of the clutch...)
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No. The delay persists in any mode or engine setting.

 

Can you describe this delay a little more?

How it feels, when it happens, what it would prevent you from doing (ex say you wanted to smoke the tires from a standstill, would it prevent that?).

I'm just trying to understand the situation a little better.

 

Lift off the throttle into a braking zone, tip back into throttle. There is a dramatic delay.

 

Ok I think I might know what you're talking about. I get that too but I can still hear the engine when I get back on the throttle so I figured it was just revs being too low. Maybe it's programmed in to keep people from spinning?

I always drive in Trac DSC, which still lets me slide around a little bit if I want to.

Do you still have it with DSC totally off?

 

I haven't tried with the DSC off, but will see if that changes behavior. It didn't feel like traction control, since once the delay is finished it will immediately go to the throttle position that matches pedal position.

Update for clarity: The behavior happens with any wheel position and RPM. You could just be cruising at consistent speed, lift, then add throttle and there will be the same level of pause before the car allows throttle.

 

Thanks for clarifying.

I just experimented with this on the way home and now I know exactly what you're referring to. If I ever noticed it in the past I must've just gotten used to it and stopped noticing.

And you're right, none of the DSC or Dynamic modes eliminated it.

 

If you're describing what I think you are, this drives me nuts. Especially when I'm trying to rev match on a downshift. I meant to ask if VelocityAP could adjust it to be more consistent but forgot somehow.

 

I'll reach out to them and see if that's something with a control table. I'd be willing to pay for a stock tune that only eliminates that delay.

 

You can adjust for it on downshifts by tapping the gas pedal a fraction of a second earlier (relative to re engaging the clutch) than you would were the throttle response immediate. I've made this adjustment almost subconsciously and didn't think of it until seeing this thread.

At any rate, interested to find out what VAP says.

 

For me it's a bug rather than a feature, so my hope was that someone had discovered how to eliminate it.

Could I drag some throttle under braking to keep it responsive for turn in? Sure, but no other car I've experienced needs that. Using the pedal has a imperceptible latency between it and the solenoid actuating.

 

I've been corresponding with Velocity AP, but suspect I'm just hitting the initial customer service representatives and not being triaged to anyone familiar with the map. They have simply answered, "Yes, our tuning is consistently reported to improve throttle response."

I don't actually care about placebo. Really trying to find out if this is something being adjusted in the engine map.

 

I emailed too and reported "... I experimented by cruising at a constant speed, lifting, and re-applying. There is indeed a delay ...", to which he replied : " ... You may be feeling the supercharger bypass closing, because the throttle actually goes wide open at fairly low pedal input, and then it uses the bypass to modulate acceleration."

I sent a link to the thread as well, maybe Stuart will get a chance to weigh in, if there's anything more to be said.

 

Interesting, since the bypass valve on my turbo cars doesn't create this very perceptible dead zone. The turbo ones I have experience with are vacuum+spring operated, similar to a wastegate, but do not have any electronic solenoid to modulate. If this bypass is being modulated with a duty cycle table, then it could be responsible if there is a pause in the ECU there.

VelocityAP did reply and state there isn't a table that controls throttle delay, so at least I know not to chase a throttle map.

 

There are lots of things in the car that could create a delay in power delivery. For example, you have a couple in the supercharger snout which could be allowing excessive movement, and a delay in drive. You have a dual mass flywheel which (particularly as it wears) can cause a delay in torque transmission.

As I mentioned in my email, there isn't a specific map in the ECU that's programming in a delay in the throttle, but that being said - 100's, probably 1000's of people who we've provided tuning for report an improvement in throttle response. That's not a placebo. The throttle response is better. I choose my words carefully because it's not possible for me to accurately diagnose the cause of something you're reporting. Let's say your dual mass flywheel is worn out and allowing easy and excessive flywheel movement.... if I told you that our tune will fix the problem and it doesn't, then what would you say to me? That's why I'm careful with my words - I can report that our tuning does improve throttle response because I've experienced it personally, and had the same feedback from gazillions of customers.

That improvement isn't from editing some specific map that induces a delay - it's a result of the interaction of a whole bunch of factors, but 'torque driver demand' is the kind of the anchor here. How much torque the ECU commands for given throttle inputs, relative to a whole bunch of other operating conditions. What's important to remember also, is that the throttle body is open 100% at relatively low torque demand. Chris would know the exact details but from memory somewhere around 30-40% throttle pedal input will open the throttle 100%. The ECU then uses the bypass position to module torque delivery to match demand (ie, control acceleration.) The reason they do it this way is because the engine runs FAR more efficiently with the throttle wide open, and the bypass modulating than it does with the bypass closed and the throttle only partially open.

You also have a clutch delay valve - I don't suspect this is the issue, but if for example you downshifted into a corner, straight into maintenance throttle or partial acceleration you could be feeling a delay there.

I've driven our XE roughly 40,000kms (same engine/gearbox/ecu as the auto FTypes), and our FPace SVR, about 5,000kms, and multiple modified customer FPace, FType etc. I've never experienced the issue you're referring to.

 

Understood. It's also why I'm trying to determine the root cause that appears to be repeatable by other owners. Versus just trying mods hoping to improve this consistently repeatable delay.

Dual mass flywheels do have some odd feeling, but in my experience it's been during gear shifts. Not during in gear off/on throttle transition. Even the new ND2 Miata has one and it doesn't produce this delay.

I'll likely just use JLR SDD and see if I can live view the throttle solenoid opening or the bypass valve duty cylce in real time.

Unfortunately @Luc Lapierre has the tune, but still this behavior. I'd have loved for it to be something that's just a remap away.

 

Thank you @Stuart@VelocityAP for chiming in

I'll be replacing the OEM coupler in my supercharger with a solid unit from Eaton in about three weeks' time, so I'll find out then if that's a factor (for my car, at least).

In regards to the flywheel: as his YouTube audience knows, @Onca Engineering has tried multiple clutch/flywheel combinations. Perhaps he could comment as well.

At any rate: ​​​​​​this case is getting more interesting 🤔