I have noticed very distinct differences in the way the car interferes with my driving via the brake switches and a complete power cut...

The brake switches typically activate when i'm getting heavy footed in a straight line but the Gas cut is when I whip around and heavy foot a 90 degree turn

Yup it can happen. Even with VDC off I tried to floor it in a parking lot with the steering wheel turned. It didn't kick the tail. It would just ramp up slowly in first as if I started in the wrong gear. I'm sure in almost all cases the lag is not there when starting off at 2k RPM.

^ Keep in mind that "VDC Off" doesn't really disable all of the car's traction assistance. At the very least, it still has ABLS active. Not sure about other elements. If you really want to test something and know that none of the traction aids are causing something, unplug the Bosch yaw sensor under the center console (near the parking brake lever / cupholder).

Yeh I know what you mean....it’s sad. The brake switch (both) replacement did improve some but it all came back when the ambient temperatures rose above 85 degrees.

Humm.... be nice if there was a way to tap a line off the air conditioner and run it to the intake manifold.

Yup did that and the lag was still there. It was before replacing the brake switch.

subbed to read later

Throttle lag - resolved with pedal box.

PedalBox by DTE Systems GmbH - Distributed in North America by TWM Performance

my cars done this lag thing a couple times. may be unrelated to the real issue, dont care. but just a curious question. is it possible to make VDC go away, like 100% gone from the car as in REMOVED. its garbage, premium 350z owners hated it, and now 370z owners hate it and EVERY single professional race car driver that drives one on the track says the car would be 145000% better without that dumb ****. wish nissan would stop intentionally gimping their cars, and leave the driving TO THE DRIVERS.

As I said a few posts above, and has been said many times on this forum before: to kill all traction aids, unplug the Bosch yaw sensor. It's underneath the center console plastics, not far from the cup holder. If you had small hands and already knew exactly what it looked like and where it was, you could probably just pull out the cup holder and reach in and unplug it, but worst case just remove the center console first. It's only a handful of screws and plastic clippy things.

Without the yaw sensor VDC, TCS, and ABLS are all completely disabled, but you still have ABS brakes. Mine's been that way for a while now. If you're slipping the wheels on purpose on a regular basis, especially cornering for a road course and/or auto-x, the ABLS will really screw with you randomly when cornering near the limit.

With all that stuff out of the way, you can abuse your tires all you want and control it manually. I can just floor the car from a roll in, say, 2nd gear, and burn through a gear or two ("cleaning off the tires" :) ) and keep it straight with the driver inputs, and the car doesn't balk or try to do anything funny at all. It also won't save you when you're too hot in a corner, but that's a good thing - gotta learn to save yourself. VDC has horrible ideas about the right way to save it anyways :P

Good info wstar ! Saves me $$ as I was going to get the black box (dyi thread here somewhere) but I understand it only turns it off but the VDC is still partially activated. Your method is better and saves $$.

Props to you kind sir !

stretch of a question, but is it something you could snap a pic of? If I could get eyes on to what im dealing with im might feel more comfortable "worst case" tearing apart my console to reach one little wire. describe it with a little more detail if you could, aside from (yaw sensor) I dont want to unintentionally disconnect its oddly placed twin sister sensor that prematurely activates its "break right after warranty expires" mode.

does anybody know for sures if this works? anybody tired it besides you, sir?

Any of these kind of systems that claim to fix throttle response do not work for this particular problem with our 370Z.

Easiest case example. When my 370 goes into this frustrating 'mode', doing 90km/h (55mph) on the Freeway in 6th gear and flooring the pedal (WOT), if you have the ability to monitor both the Pedal Position and ECU Throttle Position (I use DashCommand on an Android tablet and Bluetooth OBD2 adapter), the Pedal Position snaps to 100%, yet the ECU Throttle Position does not, instead it will hit approx 35-40% and slowly increment (you'll feel the power slowly kick in over time while at WOT) as my speed rises until I'm doing about 130km/h (80mph), and then the ECU Throttle Position will end up matching the Pedal Postion. This is not the case shortly after start-up when the Pedal Position & Throttle Position are nearly 1:1.

Second case example. Taking off from a stand still in 1st gear. As you take off you feel that massive gap of power even when flooring (WOT) the pedal. If you could monitor Pedal Position & ECU Throttle, you could see that Pedal Position is at 100%, while ECU Throttle Position is at 20-30%, and then after about a second of delay, quickly ramps up to about 80% (this is when you feel the power come back), and the car starts to move properly again.

The system mentioned above is installed between the Pedal and the ECU. It interprets the signal from the Pedal and adjusts it based on what mode you put it on. But it still is not addressing the cause of the problem, the ECU limiting the throttle response, all it is doing is manipulating the Pedal Position signal.... your foot can do that. It would not solve the problems above in any way whatsoever.

I am not saying they do not work. The principle behind them is valid, but with regards to this particular issue in our cars, they will not resolve anything. If the car was working normally and not suffering from these problems and you installed one of these systems, yes you would notice a slight difference in response. No power increase, just response, (and again, nothing your foot can't do).

MoulaZ

I can't take a useful pic of the area or the sensor, my car's all gutted out in that area for good. It's a blocky little sensor that's screwed down and has a single wiring harness connector, and the label on it says Bosch, and it's under the center console, a little rearward from the shifter. There's no oddly-placed twin sister of it in that area. If you pull the console off it will be obvious. The service manual can be downloaded from this site in PDF form and tells you how to do that, it's pretty simple.

All of that said - I'm just providing functional information here, not recommendations on what you should do or how you should judge situations. For many people, removing or unplugging the Yaw sensor might be a bad idea. If you end up posting a "Disabled my yaw sensor and wrecked my car!" thread like those VDC-OFF threads, don't mention me in it - you're on your own and you've been warned - especially if this is a normal street-driven car and/or other people might drive your car!

And yeah, I can only imagine your insurance company's reaction, or nissan's reaction, to a totaled car from spinning off into a light pole and finding the driver intentionally disabled all the car's traction safety features :rofl2:

I've removed the tcs + yaw and in drifting 2nd gear...the pedal delay is still an issue. I had a pro driver test it last night to confirm I'm not the only one feeling this delay.

Folks, there are 2 separate issues here and they are clearly confused.

1. The yaw sensor cuts throttle when it sees enough yaw-based G to convince itself that the car is about to slide, when in point of fact the car has a heap of grip remaining. This is especially noticeable on the track when trail braking hard and deep and will most likely pitch the car to the outside of the corner being entered, which is exacly what you do not want. Fixing this is simple - see here ...

http://www.the370z.com/exterior-inte...ml#post2441058

and here

http://www.the370z.com/diy-section-d...er-switch.html

2. The gas pedal deal from low-speeds is the ECU cutting fuel/spark on the basis of under bonnet inlet air temperatures. One of our AU guys in Sydney has researched this and you can find the details here ...

370Z IATs Observations - Engine & Drivetrain - Zclub - Australia's Largest Nissan 370Z and Nissan 350Z Forum

Bottom line is that the standard ECU simply will not give you good throttle response at low speed in even moderate ambient temps based in air temps in the intake tract and the Nissan Engineering requirement to minimize emissions, rather than optimize throttle response (at high ambient inlet tract temps and low vehicle speeds, it is simple to give the car too much fuel which increases emissions).

If you guarantee cool air input temps at slow vehicle speed, then you can tune this out but it won't be simple to engineer a solution for all circumstances and you may create circumstances where passing an annual emissions check could be a problem.

RB

I have a lazy foot and the pedal box sends a signal to the mass air flow meter. If I am not getting ANY throttle lag....then I would say it's fixed. :tup:

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

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

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.

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 = :happydance: :driving:

DTE PedalBox In Action - YouTube



:tiphat:

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.

You also have an automatic, so there is an extra step in the response. The rev up and the tranny downshift. That's why I only run a manual it's in gear and out of the gate a like gunshot..

aside from the obvious causes (intake air temp, coolant temp and oil temps), what else could be causing this throttle lag???

I've pretty much eliminated IAT as the cause.

I'm now leaning towards the EGR system which involves the CVTC system. EGR is intended to reduce emissions by reducing combustion temperatures....by filling part of the cylinders with exhaust gas to effectively reduce the available volume for oxygen to enter/fill the cylinder.

This is no easy fit-a-blank experiment and will need someone with tuning experience to chime in... i've got an Uprev tuner license so if someone can guide me, i am happy to guinea pig my car for the benefit of everyone as we try to solve this mystery once and for all.

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

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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.

Knock sensor could be causing the problem. Going by what I've read on this site, vibration from the drivetrain or exhaust can also bang the sensor.

i've pondered that possibility but eliminated it because it seems a bit bizarre for an engine to develop a vibration or harmonic issue at certain operating temperatures. It's not impossible because i know the engine does vibrate a lot. I have the plastic engine covers removed and to avoid losing the nuts/bolts, i just nipped them up on the intake collector. I pop the hood once a week and 70% of them have become loose by several turns.

Cant be a bad batch of knock sensors either because of the widespread awareness of the problem.

The other issue is it seems that most people are complaining about the lag in 1st gear only. Assuming that most folks are running stock intakes, i'm willing to bet that they are experiencing heatsoak of the IAT sensor - ie, ecu sees the air entering the engine as being hotter than it actually is; due to radiant heat influences from the headers, radiator airflow etc.

There is, without a doubt a difference in throttle response between oil at 90*c or less with coolant at 87*c or less versus oil and coolant temps above these approximate figures. The simple stab-the-pedal test shows this in a no load scenario. Someone on here datalogged the lag and it clearly shows a delay of several seconds between pedal activity and throttle body activity with VDC off during a 1st gear takeoff - this was done with IAT at 104f/40c which is definitely in the high territory. This is the lag that keeps you at the lights while the wanker in the bone stock Civic takes off.

I have experienced severe 'heatsoak' by intentionally using a different IAT sensor (one which reads higher, ie different resistance curve for those familiar) and it will affect you even when you're moving. Overtaking is scary. Gaining speed takes an eternity. Not fun.

I'm wondering, for those of you with remapped throttle tables - do you still experience the acceleration lag both on take off and in-gear acceleration?

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.

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.

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!

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

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

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

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

Your talking about this pipe correct?

http://i1311.photobucket.com/albums/...psuvxrpy17.jpg

spot on! for anyone wrapping it, wrap the section near the VVEL motor also.

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

I have a guy who will get those cams to crack open in nano seconds ;) pm me or email me I'll get y'all in touch here in San Diego! Migger93@hotmail.com


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Cams no problem, although you needed to do your own coolant flush :hello::tiphat::roflpuke2: