Nissan 370Z Forum

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-   -   Gas Pedal Delay (http://www.the370z.com/engine-drivetrain/20402-gas-pedal-delay.html)

juld0zer 03-04-2015 08:40 AM

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!

cab83_750 03-05-2015 01:08 AM

Quote:

Originally Posted by Zed-Hed (Post 3126203)
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.

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

Jordo! 03-05-2015 01:20 AM

Quote:

Originally Posted by juld0zer (Post 3127867)
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.

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

Zed-Hed 03-05-2015 05:13 PM

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

juld0zer 03-08-2015 07:26 AM

Quote:

Originally Posted by Jordo! (Post 3128851)
Can you show me that on a diagram or underhood pic -- I'll see if I can data log.

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

Trilitheum 03-08-2015 08:56 AM

Your talking about this pipe correct?

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

juld0zer 03-08-2015 10:32 AM

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

MagmaRed370z 07-24-2015 07:32 AM

Quote:

Originally Posted by Zed-Hed (Post 3129545)
Do we know if this condition is present in 2015 models.

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

FairladyZ40th 02-17-2016 02:56 PM

Quote:

Originally Posted by cossie1600 (Post 571408)
The world of emission and drive by wire, the computer opens the throttle gently rather than snapping the plates open for emission purposes. I have been saying that the 370 feels like it has less throttle response than my 350, I am starting to think I am right


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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birdman71 02-17-2016 03:01 PM

Quote:

Originally Posted by FairladyZ40th (Post 3416060)
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:

FairladyZ40th 02-17-2016 03:02 PM

Lol I did that freaking flush like 3-4 times too!!! Leave me alone XD hahahah


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FairladyZ40th 03-10-2016 06:52 PM

Quote:

Originally Posted by cfleming2226 (Post 571353)
Has anyone experienced a brief (about 3 - 5 sec) delay from the time you push down on the gas (floored it) to the time you actually accelerate?



I was out the other day about to merge (Honda with a tin can exhaust next to me) so I floored it to jump ahead of him and there was a good 3 sec delay ... really disappointed. Especially because in my head I was gonna own this guy, but by the time I accelerated I had to slow back down to let him in!


Ran into this, might be of help? Idk worth taking a look at, read the description :)

https://www.stillen.com/performance/...ssan-370z.html

"These grounding kits will also improve the shifting on automatic transmission vehicles, and in most cases noticeably improve shift times and reduce lag."


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tjlazer 03-11-2016 02:27 PM

That's not it, it's a known issue with some. Even on 6MT. It might be related to intake temps. When I start having this problem I have to launch at 3000 RPMs to avoid this issue, very frustrating!

FairladyZ40th 03-11-2016 03:56 PM

Quote:

Originally Posted by tjlazer (Post 3434267)
That's not it, it's a known issue with some. Even on 6MT. It might be related to intake temps. When I start having this problem I have to launch at 3000 RPMs to avoid this issue, very frustrating!


Oh then in that case, a tubbing will help you millions with this issue but yeah I agree. The temp makes the car lag. I just simply suggest a good venting body kit i.e. Fenders bumper and hood haha. Blast your heater with the windows down :)


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ZeN 10-06-2016 10:08 AM

Hot climate sucks
 
Gents, it is 33-38 degC plus humid all year long here in Malaysia, i've been having this trottle delay since my 1st day ownership. Have anyone tried use another IAT sensor which has the same resistance curve as OEM and relocate it to the mouth of the intake? It is embarrassingly slow to take off in any low gear when the rpm is around 1-3k, above that it scream all the way to redline. In a heavy traffic jam, IAT is always about 40-50 degC above cabin ambient temp reading, i logged all this with OBD2 and Nissan Datascan III app since the car is JDM. No issue with brake switch as i can see the value for both sensor switched. Idle timing was awfully low at about 3 compared to 9 when cold start. The only thing i've been wanting to check is the knock register and MAP sensor barometer volt value but theres no parameter of it in the Android app i have, no codes either. Maybe that was caused of the timing retard, had checked flexplate and theres no crack. Also have tried removing the MAP sensor driving with CEL codes and it didnt improve or making it worst. Happen on either full tank of fuel or low. Only good temporary solution that work only for short period of time ~15 mins is refuelling when near empty ~ 40 litre. Nissan tech had even datalog with consult III while me driving and cant find anything wrong.

Intake were all stock with addition of 36 row Z1 oil cooler and 25 row AT cooler to the sides. I really hopes we as a community get to solve this teething heatsoak issue. Car had 125000 KM already since i daily drive it to work since 2010. My next fault finding would be to replace MAP sensor and see if it is faulty. Envy you guys in colder climate country.


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