Gas Pedal Delay

H2O_Doc

Is this something that one wouldn't need if getting a tune?

SouthArk370Z

The person doing the tuning should be able to modify the table that handles throttle pedal position/response. There is a thread on this site that gives examples of tables that improve throttle response. IIRC, does a much better job than a pedal box.

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ZForce

It added to my tune, so yes IMHO and thru self testing found that it was a benefit EVEN with a tune.

Tested: w/o tune - found to eliminate the throttle lag.
Tested after tune - found to further increase throttle response.

PedalBox + UpRev Tune =

DTE PedalBox In Action - YouTube

BGTV8

And here is what the yaw sensor fix looks like ... takes an hour or so once you assemble the bits needed.

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wstar

Anything that goes inline with the electronic gas-pedal's signal and modifies it can't overcome the fact that the ECU limits your throttle at lower RPMs - only tuning the ECU can affect that. What the "pedal-box" type units *can* do is change the shape of the response curve of the pedal itself, e.g. put the 50% mark down at 20%, so that you get more response out of less foot movement, or vice-versa. Ultimately, anything the pedal box can do, your foot can do as well if you move it differently (e.g. stomp gas faster, or use the pedal more precisely). And then of course there's temps vs fueling in the ECU, and the yaw sensor hack, as noted by BGTV8 above

Mostly, I tend to view the pedal-box type things as psychological in nature. You could make the car do the same thing with more foot movement, but the car feels more "edgy" if you barely move your foot and lots of things happen quickly.

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TheBoomSpoon

I have the 7at and never noticed this stock or after bolt-ons with tune. Ill consider myself lucky

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juld0zer

with an auto trans, most of the lag would be masked by te fact that it shifts itself.

Owners of manual 370z's feel it because say you're in 3rd gear and you sink your foot under lag conditions, nothing happens then all of a sudden she takes off. The feeling is most akin to the VDC kicking in and killing the power.

SouthArk370Z

High IAT will cause the ECM to retard timing (and probably other things). IIRC, it starts backing off around 85-90F. I've noticed some lag/bog in stop-and-go traffic in the Summer. Usually clears up once I get moving and measured IAT drops to closer to ambient. There does appear to be significant thermal mass to the sensor and/or housing as it takes a while to drop.

My IAT reads 6-7F high but it hasn't been a big problem for a DD.

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Zed-Hed

Why is it that no tuners are familiar with the gas pedal delay. I've talked to several and they don't know anything about this.

cab83_750

IMO, the Z-market is way too small (I.e., not much profit in it) for someone to invest the necessary R&D.

juld0zer

because the consensus blames 'high' oil temperatures. that sells oil coolers, which leads to a placebo effect in most cases (IMO).

External oil coolers are neccessary for earlier models which did not come with the oil to water heat exchanger fitted in 2011 and onwards models, and hot climate models. But on 2011 onwards models, it's overkill for street driving - even spirited street driving. It does a decent job at keeping oil temps under 100*c under most 'normal' operating conditions.

The other issue is the VVEL system. It's a very capable system and a pretty complicated system. I have never taken off the accordion pipes and ran the engine but i've heard it here a few times that the throttle bodies are wide open most of the time except under certain conditions, such as to build brake booster vacuum. The same folks reckon the ECU sends a pseudo-TPS signal thru the OBD2 system so for those who monitor via OBD2 you'll argue like me that the TPS suggests that the throttle bodies are NOT wide open most of the time.
Anyway, my point is that there's so much misunderstanding of VVEL - and also its oil requirements (temperature demands, for example). VVEL works fine even at 100*c oil temp in hot ambients. A more aggressive throttle map does wonders. But throttle mapping isn't easy and it's a bit of a trial and error experience sometimes.

There is definitely a delay in throttle response - i have seen it on logs. The ecu registers gas pedal input very quickly, but it opens the throttle bodies slowly and it does not open it as much as you expect. Likewise for VVEL activity. This is where an aggressive throttle map helps but doesn't eliminate the problem completely. Throttle mapping with VVEL is difficult because the tuner or yourself never has complete control over the translation of gas pedal input to throttle activity (ie. throttle bodies and VVEL). The ecu still has the final say.

What i have tried to learn in recent times is why the throttle response seems to become noticeably more sluggish when the motor is fully warmed up vs when it is still warming up or when it is cold. This is based on oil temperature, not coolant temp because we all know that coolant temps get hot very fast on modern engines to promote lower emissions.

If anyone wants to take the lead, i'd like to see what happens if you insulate the centre coolant pipe (the big one running underneath the actual metal intake manifold from the coolant filler neck to the rear of the head). Wrap it in exhaust wrap or throw some Earls fire shield over it. This is the final frontier when it comes to eliminating heatsoak because it's after the IAT sensor and the ECU doesnt know what happens in this area. But this assumes you have an insulated cold air intake system that doesn't get heatsoaked severely at a standstill - so the guinea pig will have to sacrifice some engine bay aesthetics in the name of science.

The other theory i have is that the VVEL motors are overheating and they get sluggish as they get hotter. But it should log a fault because the target angle isnt achieved - i guess that depends on how the ecu is programmed, in terms of how long does it give the actuators to respond.

Anyway, good luck My Z is for sale but it's been one awesome experience despite the lows. This is an awesome community of very knowledgeable people and it is the best car forum i have been a part of to date. The support, the experience, the info and guides - all make for a great Z ownership experience. I hope i have contributed and made a difference in somebody's Z experience but i'll still be around!

Jordo!

Can you show me that on a diagram or underhood pic -- I'll see if I can data log.

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Zed-Hed

Do we know if this condition is present in 2015 models.

MagmaRed370z

I can say to the 2014 but I don't know about the 2015s.

juld0zer

Here's he part number for the pipe
21021JK20A

You can sort of see it if you follow the filler neck downwards and look towards the rear of the engine