Power band at 4000 rpm

[jdm2003]

I was just wondering if there is a way to spread the torque across the rpm rang more evenly.

Example

Running onto the motorway 2nd gear.

Throttle 3/4 of the way down, power is smooth traction control is locked in,

soon as i hit 4000 the back wheels light up !! (slip) (slip), must be around 50 mph.

Its caught me out in 3rd also. not long had the car mind, so also wondering if its just how its tuned. Ill be clear i'm defiantly not complaining out it.

[Ekona]

No. Adjust your right foot, it's easier and cheaper.

[GMballistic]

^^ What Ekona said but also Op what tyres are you running with & are they in good condition?

[Irn Bru]

And the roads at this time of year are covered in crud, i've had my 2.5 tonne Jeep slide out going at 30mph round a corner !!.

Edited December 24, 2016 by Irn Bru

[-G-]

Whatever you do, don't be tempted to knock the TCS / VDC off. You'll end up in a ditch or worse trying the same trick again.

 

Fair warning.

 

Incidentally, what diameters are you running front and back?

[jdm2003]

Cheers guys , im on Michelin super sport 19" DE Stardard. just put a steel induction tube in . only mod.

had the back out when shifting down a few times . Hint taken

[Strudul]

Brembo Break Setup, Nisimo Styling, Rolled Arches, Dotz 19" Michellen Super Sport Tyers, C West carbon wing, Custom Exhaust,

Standard DE Engine.

Off topic, but 'Nismo', 'Michelin', 'Tyres'.

 

[jdm2003]

Tires are good, TCS stays on. Im not hero enough to turn it off.

Edited December 23, 2016 by jdm2003

[AMT]

Be extra careful with that right foot just now, a fresh coating of heavy sleet came on yesterday as I went up hill (at a slow pace) and the thing was starting to get unsettled... mind you I am kicking about on MPSS

[Irn Bru]

Also a good idea to be in 3rd or and preferably 4th by 50 mph at this time of year

Edited December 23, 2016 by Irn Bru

[jdm2003]

Yeah we get allot of fog where i am to so roads are greasy quite a bit of the time.

But can any one explain why the power band is where it is and why please.

I know how my engine works, but because i have no history with the car im not aware if this is standard behavior or mapping.

[Jetpilot]

The cicra 20hp or so that mapping adds really wont be a game changer or completely change engine characteristics, it will just be where the cams come on song, you will probably find its just road conditions causing it to spin up, I wouldnt think are any cars with 300hp ish where you can just put your foot to the floor in winter without the same result.

[jdm2003]

Thanks Jetpilot

found this info looking around.

The cams have a dual set of lobes, and the shaft is moved to use the set the RPM's dictate.

So at around 4000 RPM the cam lobe is changed and more power is produced.

CVTCS (Continuously Variable Valve Timing Control System)

Edited December 24, 2016 by jdm2003

[ZMANALEX]

50mph in second gear, in rubbish weather conditions.

 

You have answered your own question.

[TT350]

I remember a post like this not long back where the guy was complaining the rear was breaking loose in 3rd at 1500rpm when going round a roundabout.

 

Had my BS meter going off the scale.

[Strudul]

I remember a post like this not long back where the guy was complaining the rear was breaking loose in 3rd at 1500rpm when going round a roundabout.

 

Had my BS meter going off the scale.

Not sure if you're referring to me, but it does sound familiar (though in my case it was 2nd).

[Ekona]

Yeah we get allot of fog where i am to so roads are greasy quite a bit of the time.

But can any one explain why the power band is where it is and why please.

I know how my engine works, but because i have no history with the car im not aware if this is standard behavior or mapping.

What do you mean, where the power band is? It's a large NA engine, so you have bags of torque low down then a good dollop of power which tails off just before fuel cut. That's it, no magic or anything.

 

You're going to have to understand the relationship between your right foot and grip on the road surface before worrying about power bands.

[jdm2003]

Im not worried at all lol. Just Curious as to why the power comes in hard at 4000 revs, found my answer.

Its the cams

 

found this info looking around.

The cams have a dual set of lobes, and the shaft is moved to use the set the RPM's dictate.

So at around 4000 RPM the cam lobe is changed and more power is produced.

CVTCS (Continuously Variable Valve Timing Control System)

Thanks for every ones concern about my right foot lol

[Ekona]

Continuously Variable.

 

Continuously.

 

CONTINUOUSLY.

 

That should give you an idea as to when it operates. There is no VTEC-yo changeover point, there is no big kick in power, it's purely you're using too much throttle for the conditions. Power builds linearly, so more throttle = more power.

[Aashenfox]

Im not worried at all lol. Just Curious as to why the power comes in hard at 4000 revs, found my answer.

Its the cams

found this info looking around.

The cams have a dual set of lobes, and the shaft is moved to use the set the RPM's dictate.

So at around 4000 RPM the cam lobe is changed and more power is produced.

CVTCS (Continuously Variable Valve Timing Control System)

Thanks for every ones concern about my right foot lol

 

This is not your answer. 350zs are not 'sudden' in the same way that a turbo car or a Honda VTEC systme is, they are smooth all the way up. Either you ARE doing something wrong with your foot, or your car has a problem. Go for an alignment.

 

While I'm not going to immediately suggest that you are the problem like some of the other members, I have to ask...is this your first (fast) rear wheel drive car? If not, fair play, but I gotta ask before I send you down to your dealer for a checkup.

 

Once again, so we're clear and to answer your original question...no, this is not a peaky car, no there is no natural reason why you should feel a surge of power at 4k rpm, and CERTAINLY not enough to make the car twitchy. Now, if you floor it, in any gear, at any revs, with the front wheels anything but straight, you're going to do some snaking around, that IS normal, and is why I asked if it's your first RWD car with more than 200hp

 

That cam thing is a red herring. YOu want aggressive cam timing? Go try an S2000, there's a MASSIVE surge at 6400 rpm when the cams switch. The Z also does this, but is not even remotely comparable in terms of a 'kick', the Z is usually as smooth as butter (that's why you would buy an NA big capacity car).

Edited December 24, 2016 by Aashenfox

[Strudul]

Everyone seems to be missing the point of the question...

 

He isn't asking how to avoid it or complaining:

Ill be clear i'm defiantly not complaining out it.

 

He purely wants to know why he is experiencing the wheel slip at 4k RPM.

 

This is with a constant throttle position (3/4 depressed), and presumably in a straight line.

 

As such, gear and a heavy right foot should make no difference, it's purely a matter of there being a larger increase in power / wheel speed at 4k RPM.

[jdm2003]

Thanks Strudul , that's exactly right ,

The power is smooth until 4000rpm then it feels like it hits a large Torque curve.

if the power was smooth the back end would be all over the shop from the start, not build smoothly to 4000 and release the beasts lol

I dont mean to ruffle any ones feathers or make a BS post. Its just some thing i was wondering about as i have no service history with the car and its got a custom exhaust.

It has not been remapped as i know of. its limited to 112 - 114 in 6th.

Fantastic machine

[Aashenfox]

Everyone seems to be missing the point of the question...

 

He isn't asking how to avoid it or complaining:

Ill be clear i'm defiantly not complaining out it.

 

He purely wants to know why he is experiencing the wheel slip at 4k RPM.

 

This is with a constant throttle position (3/4 depressed), and presumably in a straight line.

 

As such, gear and a heavy right foot should make no difference, it's purely a matter of there being a larger increase in power / wheel speed at 4k RPM.

Right then boys, if I'm missing the point, find me a dyno plot with a surge at 4000rpm.

 

http://www.350z-uk.c...ts-info-thread/

 

I'm looking PAST the OP's question, because it's not a valid question, in the same way 'why do pigs fly south in winter?' is not a valid question...because they don't!

Edited December 26, 2016 by Aashenfox

[Tricky-Ricky]

Thanks Strudul , that's exactly right ,

The power is smooth until 4000rpm then it feels like it hits a large Torque curve.

if the power was smooth the back end would be all over the shop from the start, not build smoothly to 4000 and release the beasts lol

I dont mean to ruffle any ones feathers or make a BS post. Its just some thing i was wondering about as i have no service history with the car and its got a custom exhaust.

It has not been remapped as i know of. its limited to 112 - 114 in 6th.

Fantastic machine

 

 

If that is the case then i would suspect that the CVTCS has either been reprogrammed to cut in much more at 4k RPM (if that's possible through Up rev?) or is faulty and the solenoid is not kicking in and you just feeling the the cams sweet spot because its not working correctly

[nub]

Any remapped vtec Honda or s2000 will lose the vtec kick and have 100% smooth power curve.

The vtec kick is because there a dip/loss in power before higher can engages. If the roads are even slightly damp then don't expect to get full traction in 2nd. Also summer tyres need to be above a certain temp to perform properly. I've had a 370z around a week, uprev remap to 345 or so and it feels like I have a torque surge at 4000rpm to, but I may be wrong. You're tyres are good and I drove today in the dry (yet cold) and was able to get full traction in 2nd, in the summer with some AD08s I reckon I might be able to launch in 1st without too much spin but I'm not sure. To summarise, don't floor it in the wet. You may be able to floor it in 3rd with wet roads on stock power, but I'd feel more confident on 4th if have to overtake etc. I don't really understaffed my torque map, it's not smooth like my old Supercharged FN2. One day I will remap with. ECUtek and get some more power.

 

 

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