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Discussion Starter · #1 ·
just curious. it seems like i never get it over 3k rpm's on the highway. even when i punch it, it RARELY gets over 4k. who out there has gotten the thing to redline and what were the circumstances?

kirk
 

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A guess but try dropping it into L)ow.

kirk said:
just curious. it seems like i never get it over 3k rpm's on the highway. even when i punch it, it RARELY gets over 4k. who out there has gotten the thing to redline and what were the circumstances?

kirk
 

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kirk said:
just curious. it seems like i never get it over 3k rpm's on the highway. even when i punch it, it RARELY gets over 4k. who out there has gotten the thing to redline and what were the circumstances?

kirk
Perhaps my CVT is malfunctioning but if I mash the pedal on the freeway (cruising at 70-80mph) it usually gets up damn close to redline.
 

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kirk said:
just curious. it seems like i never get it over 3k rpm's on the highway. even when i punch it, it RARELY gets over 4k. who out there has gotten the thing to redline and what were the circumstances?

kirk
I don't think to many people redline their Mo's for very long if ever. One sure thing that will happen is that your fuel economy will go into the toilet.

My training as an engineer always wants to ensure that I do not over extend the engine so that it last a long time.
 

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Discussion Starter · #5 ·
i'm going to try mashing mine on my way home and see what happens...

it just seems like a low rpm running car - nice, smooth and quiet.
 

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And my training as a technician makes me want to test it every now and then, to see that it will indeed meet engineering's specs. :D

Although I only do it maybe once or twice a month (A lot less now than about $1.50 ago), I do it in DS and accelerate for 5 to 10 secs.
This could mean from 30 to 80 MPH or from 65 to 100MPH or so. Once it is there, I don't leave it there very long.

Homer
 

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In your average car, you can get it pretty near redline without flooring the pedal (say 3/4 throttle). With the MO, you need to bury your foot to the floor, and the CVT will kick it up a few gear ratios and send you screaming towards redline.
 

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I've hit redline a few times. In normal D mode it takes a while before it jumps up there, but if you drop it into S it will get there pretty quickly.

As stated above, you do need to floor the pedal. And I mean completely. That's how you explain to it that you want maximum power. Let up a little bit, and it will think that you want to let up the power. Makes sense, right? :)
 

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The engineering degree in me says there is some headroom left above redline - so redline is safe :) Need to make sure it's "In Spec" ;)
 

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I would guess the reason that the Murano doesn't actually go to redline or beyond is that it is not needed!
Let's think about this for a second. If you want the ultimate acceleration then the best way to get it is to get the RPMs to right where the engine is producing the highest horsepower. In most cars, redline actually produces less than the maximum hp!
So why redline any car? Well the answer to this is that acceleration is directly related to the average hp. So even though redline produces less than max hp, as soon as the next consecutive gear is achieved the rpm drops putting it close to the max hp rpm range. So in essence, redlining a car is only beneficial because the average rpm is close to the max hp rpm.
In a CVT, this method need not apply as this transmission is advanced enough that instead of hovering around the max hp rpm(by passing it redlining then going below it as soon as you shift gear), why not just stay put at max hp rpm. For the Murano this is 5600 rpm. There is really no need to redline as this would actually be lower performance than at 5600 rpm.
 

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Drive around in L for a few minutes... You'll find a very different personality. Higher engine braking and the engine rpm will stay up there a fair bit.
 

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Kan-O-Z said:
I would guess the reason that the Murano doesn't actually go to redline or beyond is that it is not needed!
Let's think about this for a second. If you want the ultimate acceleration then the best way to get it is to get the RPMs to right where the engine is producing the highest horsepower. In most cars, redline actually produces less than the maximum hp!
So why redline any car? Well the answer to this is that acceleration is directly related to the average hp. So even though redline produces less than max hp, as soon as the next consecutive gear is achieved the rpm drops putting it close to the max hp rpm range. So in essence, redlining a car is only beneficial because the average rpm is close to the max hp rpm.
In a CVT, this method need not apply as this transmission is advanced enough that instead of hovering around the max hp rpm(by passing it redlining then going below it as soon as you shift gear), why not just stay put at max hp rpm. For the Murano this is 5600 rpm. There is really no need to redline as this would actually be lower performance than at 5600 rpm.
This is all true, except you mean torque instead of horsepower. Torque is instant power at a given RPM, horsepower is the Torque times distance travelled. Torque is what you feel as "power".

With this engine, there should be 2 torque peaks, one in the lower RPM range (below 4000) and one in the upper. At 4000 RPM, the intake area is opened more.

I have the pop charger, so these RPMs are a bit higher than those with a stock intake. I've found the lower torque peak to be about 3250, and the upper one to be about 5100 RPM.

So if you can manipulate the throttle to keep the RPMs at those values, you'll get better acceleration.

BTW, the TechnoSquare ECU that I'm looking at getting ups the redline to 7100, which is a common number that ECU upgrades use for this engine.
 

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Oh, and it's MUCH easier to redline when flooring it from a stop than doing it while moving at any speed.
 

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About floring the pedal, I'm not looking for the redline, I'm testing how it accelerates and I'm feeling something odd. And I say "feeling" because this might be just my perception.

From a standstill, when floored, rpms go to like 5k or 6k and the vehicle comes to 50 mph very, very fast...like a rocket. But after that it doesn't seem to accelerate much more, but rpms are high...like reaching a flat point. Seems like straining the engine.

Now, doing the same test, after reaching I get the pedal a bit back and I hear and feel the vehicle "shifting" and giving more speed.

Have you experienced this? Is this the normal behaviour for the Murano's CVT system?
 

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I assume this is normal, mine has worked that way from the beginning. Some people might not notice it if they let off on the gas too quickly. I try to get other people to experience this when they are driving my MO, but they never let off on the gas slowly enough.
 

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It seems to me that the computer is programed to move rpms linearly with the gas pedal. The CVT will try to maintain the revolutions as high as possible when floored and positions in between depending on how deep the pedal is pressed.

If this is the actual working, then there's a catch, because the power band of all engines depend on rpms and that's why conventionally you have shifting gears.

So, if the engine just stays at the top rpms then acceleration will be limited if the CVT doesn't move between peak torque and peak hp. This is done beautifully at moderate/low driving, you can see the rpms changing for a given pedal position.

If the system is bias towards speed, as in the pedal position dictates speed, then the case is worst when floored. The CVT should get peak torque up to a given speed, then move to peak hp for top acceleration on to the top speed dictated by the pedal.

If bias towards rpms, then at the last stage top acceleration would go on to the top speed available for the given rpms.

It could be a combination of both, but I think it works bias at speed. The other modes offered with D go for more torque at the wheels.

Probably the program will be improved with customer reports, but I definitely feel the lag after 50mph when floored. I don't remember the peak rpms, but I think it goes over them, and we all know that there's not much power near the top.
 

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Yeah theoretically the CVT should not ever exceed the hp peak, where the engine is providing maximum acceleration. But it does anyways, so there must be a good reason the engineers programmed the CVT computer to let it do so.

In a conventional manual or automatic, it makes sense to exceed the hp peak RPM since this may push the revs into a meatier part of the powerband after the next upshift. For the CVT, this is not the case.
 

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Eric L. said:
Yeah theoretically the CVT should not ever exceed the hp peak, where the engine is providing maximum acceleration. But it does anyways, so there must be a good reason the engineers programmed the CVT computer to let it do so.

In a conventional manual or automatic, it makes sense to exceed the hp peak RPM since this may push the revs into a meatier part of the powerband after the next upshift. For the CVT, this is not the case.
If the engine never exceeded the rpm's @ peak hp you limit the top speed available. The SE 6 speed manual mode for example would not be able to go to the redline for those who care about such things.
 

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Eric L. said:
Yeah theoretically the CVT should not ever exceed the hp peak, where the engine is providing maximum acceleration. But it does anyways, so there must be a good reason the engineers programmed the CVT computer to let it do so.

In a conventional manual or automatic, it makes sense to exceed the hp peak RPM since this may push the revs into a meatier part of the powerband after the next upshift. For the CVT, this is not the case.
How's this for a reason? - limiting strain on the CVT
 
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