Dont know if theres anyone here thats noticed how the CVT is really sluggish about letting the engine rev to redline sometimes??

Doing frequent 2-lane road highway passing at 65-90mph, I notice times when I hit the pedal to the floor and it takes a good 5 seconds to slowly rev up to redline. Other times, it will immediately jump to redline and take off like a bat outta he11.

What I've figured out just recently...going cruise throttle and immediately stomping it to WOT makes it slowly rev to redline....like it'll take FOREVER to go from 5000-6000rpm. However, mashing the throttle to 1/3rd throttle for a second, then quickly to ~2/3rds throttle then mashing it quickly to WOT gives that "holy **** what just happened" jump to redline immediately.

Anyone else know what I mean....or more importantly, what the CVT is doing?

I suspect that it has to do with the torque converter remaining locked versus unlocking. There has even been twice that it has zipped up to redline so quickly that it revved to a full 6500rpm...those couple of times I was in Phoenix (1000ft elevation versus my normal 4500-7000ft) and the acceleration was actually pretty unmanageable. It startled me with the amount of torque steer it had. I've noticed that it never seems to settle into exactly the same rpm twice in a row. When it's being lazy, it hits 5900-6000rpm after 5 or 6 seconds and sits there. Most of the time it locks in right at 6200-6300rpm, and sometimes it'll bounce up to 6400-6500rpm and slowly back down to around 6200. The times when it bumps the revs high and fast are the times that it REALLY surprises me and I feel all warm and fuzzy inside.

Anyone share my experience?

Late,
Trav

 

ive noticed the CVT tends to adopt your driving habits. for example if you normally cruise at 1800 RPMs most of the time, when you go to punch it, it will slowly accelerate almost like the car is in fuel-economy mode or somethin'. since ive tossed a bunch of mods on mine and drive "spirited" the CVT reacts well when I punch it, I almost never have it do what you're talking about anymore.

although like you said, it's a little more than just mashing the pedal. gotta play with how much you push the pedal and I wouldn't punch it from a low RPM, get the car moving then punch it

 

Yeah. I know there's some brains behind it when I get back in the driver's seat after my roommate drives it for a few hundred miles....when I hit it to the floor, it's like the CVT doesn't believe me. LOL

But even if I'm in the driver's seat for a week (which I have been...about 700 miles total) and going 50-60mph. When I go to pass someone and stomp it to the floor, I have to be careful how I do it. ESPECIALLY if you floor it, then hesitate and lift up on the throttle a bit, then floor it again....the CVT just won't.

But it's like if I get the revs up before I actually punch it to the floor, it pops up to redline MUCH faster and just GOES. Whereas at a steady highway cruise, just quickly flooring it....most of the time....it very slowly ramps up to redline. Hard to explain. I'll have to get some videos and post up.

Late,
Trav

 

well, while racing,, i usually cruise at 80 km/h,, i put the gear on manual at the first gear. the RPM will be at 6000rpm, then step on it but before the gear changes to second i put the gear back on D... this will give u a good advantage because the CVT like u said will take forever to go to the red line...

this technique was done and it worked effectively..

 

^ I used to have to do that too, "manually shift" so the car was in the right gear first of all, THEN let the computer take over. it's hard to explain (just as hard to explain as the OP is mentioning) but i really don't have to do that anymore

 

Correct, after having the valve body replaced due to boggy acceleration in my 2010 the Nissan tech said the same thing about it re-learning your driving habits. It is constantly performing this function.

 

This is why people say to reset your ECU manually after a performance mod, this is the only way to feel the most out of it immediately otherwise your car's ECU is averaging the new data in with the old. a fresh ECU reset = fresh datalog numbers = quickest reflection of the new power (or a good way to reset your driving habits). over time your ECU will learn the new part, but its averaging all this data in with the old data so will take some time.

 

Do abrupt throttle inputs. They change the transmission profile to something more aggressive. Or press the pedal to the floor, past the notch. It'll give you everything regardless of how you've been driving.

 

I Usually Put it in Ds for a Quick 0-40mph..Then I switch it quickly to the D mode, and I go from there . Like Ghozt says, I would cruise at a 40 dig if you ever wanna "race" anyone on the track of course. My 40-120mph is ridiculous!

I'm hoping its much better after the Injen Intake Installment!

 

I would agree with your assessment on the cars acceleration. I have on numerous occasions’ found myself struggling with an overly light steering wheel when making a pass around a slower vehicle.
Time is nearing for a spring drop to help with body lift among the obvious other things.

 

the best mod i found for low end was the stillen UD pulley, everything else shifted the power band to the high end. now i screech tires all the freakin time by accident and VDC is on

 

Ghozt man, link me please..Thanks, your best friend Maverick

 

http://www.stillen.com/product.asp?i...N&model=MAXIMA

get the gates belt as well, you need it because it's a diff length

 

Are we certain that the UDP (since it removes the harmonic damping) doesn't destroy crank bearings like some engines do? How long have you had the UDP on?

Late,
Trav

 

a few months now, no issues except slight stiffness in power steering when going slow but nothing that noticeable.

quoted from Josh@Stillen from the 350z forums - The VQ35DE engine is internally balanced, and does not require a harmonic balancer. If you look at the OEM crank pulley, you will see that the steel pulley does contain a rubber ring separating the outside area from the inside, which actually provides some NVH (noise, vibration, harshness) from actually heading back into the engine, due to the cast design. With a perfectly balanced aftermarket pulley, this isn't a concern.

 

There's no harmonic dampener on our stock pulleys. The VQ is internally balanced. There are plenty of 4th, 5th and 6th gen guys that have put thousands of miles on their VQs with UDPs and had no problems.

Edit: It's late, and I didn't read Ghozt's post. But that pretty much sums it up.

 

Harmonic balancer doesn't have anything to do with how well the crankshaft is balanced. All modern engines are balanced via counter-weights on the crank to balance the rotational forces. There's nothing special about the VQ for having a balanced crank. Harmonic frequencies occur due to crankshaft flex and rebound - with every single compression stroke where some certain rpm's are worse than others. The damper just uses the weight (inertia) of the outer pulley ring to absorb those frequencies.

Late,
Trav

 

there is no harmonic dampener in the VQ. this question has been argued to death (and resolved) on other VQ forums (350z, G35, 370z)

if the part makes you nervous - simple - don't get it. nobody has issues with Stillen's UD pulley. As Brett mentioned people have ran it for years in all kinds of VQ's

 

Like ghozt I have had no issues as well except slight stiffness in the steering wheel and have had mine over 1 month now. Had my dealership install it and check it again a few weeks after it was installed. Great upgrade.

 

I have noticed that the CVT does have some strange reactions and odd times when accelerating and decelerating but I've never really paid it that much mind to get the most out of it. As far as the ECU, I understand that this is supposed to be a learning ECU and it does a good job of resetting itself back to original settings once you disconnect the battery for 24 hours or more so i think I'll disconnect my battery and allow the ECU to do a reset then re-install this garbage BD tune to the highest settings to see if it reacts any different immediately.

 

Yeah...I agree whole-heartedly! The other day I had to semi-panic brake onto the shoulder to let popo around me (and hope and pray it wasnt me they were after lol). As soon as I was stopped, he went by and I pulled back out....hit it to the floor and it barely crept away and reached an awesome 3000rpm. Thats where it stayed for a good 10 seconds. Like it totally freaked out. One thing for sure with mine....it never does the exact same thing twice. Thats part of what I love about this car...others would hate that, but I think its cool. Lol

 

Yeah....I'm not gonna beat a dead horse...its very well documented on lots of forums on both sides of the fence. I see validity on both sides.

Ya reckon the majority of the power freed up comes from the reduced mass of pulley itself or reduced diameter and underdriving the PS pump, alternator and occasionally A/C? I really have no concept of how much power the accessories sap away? Do y'all know?

 

I said this once and ill say it again .....the things I read on forums sometimes blow me away.....

I've had the pulley for about 100k miles n the only thing wrong with this mod is changing the belt every 50k depending on how you drive and weathering.

good luck with the longblock VQ35 theories

 

Probably more gains due to less weight, comparing the weight of the pulleys stock is like 5 lbs the Stillen is 1 lb. i havent seen any electrical issues either, and i have an amp/sub in the trunk.

 

I think it has a lot to do with weight n the size of pulley

and I have no electrical issues either

 

Freakin Stillen jacked me, they sent me a belt that is too small for my UDP.

 

Thanks Ghozt, I'll add it to my to do list!

 

really? that's weird. you sure you moved the tensioner to put it on? it should spring back and hold the belt tight

 

on the stillen site should i buy the pully and the belt they r seling?

 

yeah, the belt is a shorter belt which is needed.

this is a great mod, still hasn't blown up the car almost half a year down the road. only thing i noticed is when it was really cold the other day my gates belt was squeaking a little; it stopped after a few minutes and i havent heard it since. like Wally (ifuxwituz) said I can see needing another gates belt probably every 30-50k miles depending on driving habits, but other than that I love this mod!

 

What kind of tuner do you have? I’ve been looking to get one.