I was wondering at what RPM level would you be able to get the most performance out of the Maxima. The info I've heard from my friends have been contradictory. One of them say @ peak torque, the other says a peak HP. The problem I have is that you want a medium or halfway point between the two. Basicly in the middle of peak torque and peak horspower. Any of you know this RPM shift point? Would it matter in which gear it is?

 

What what I remember (I could be wrong), you should shift at redline in 1st, shift at about 6K in 2nd, and 6K in 3rd. Try searching in the General forum because I remember it being discussed in there (keywords: "shift point").

 

In a 2k Max, shifting at redline will give the best results. Shifting any sooner, will give a slower ET. Ive tried it at the track. Shifting at even 6000 instead of 6500 rpm gave an ET of about 0.1 sec slower or so if I remember correctly.

 

in 2nd and 3rd gear, shifting at redline isn't quite as useful since the revs will be beyond where the torque begins to peak. You want to shift at the point where the rpms in the next gear is at the point where torque begins to climb.

If I get gear specs and final drive specs, I can do some calculations once I have some spare time (which is never! lol)

 

>You want to shift at the point where the rpms in the next gear is at the point where torque begins to climb.

correct me if I'm wrong (or just being a smart-***), but taking what you've just said literally, we should all shift just past idle (750 rpm) since torque 'begins to climb' after, oh, 1 rpm !!!

Here's a counter point. Those w/ the 5th gen should realize a sudden surge of power as at 5K rpm, right when the manifold changes into the short runner config. Sort of like a 'V-Tec' or turbo rush feeling. Since you can really feel the increase in power (dyno graphs also show this increase) wouldn't it be wiser to be at, or as close to 5K rpm after shifting? If the above is true, then in order to have maximum acceleration, shifting at redline is necessary.

My only beef w/ this is that fuel cut is only a 100 or so rpms later. And w/ the tendency of this engine to 'overrun' just a bit when you take your foot off the gas, you'll be bouncing off the rev limiter. Unless, of course, you have the reflexes of a cat and the speed of a mongoose!

In case any out there didn't know, bouncing off the rev limiter is not a good thing. Ya heard it here first!!

 

Ive got the program to calculate shift points based on a dyno graph and gear ratios. (Or if can be done manually, its not all that hard.) But, simply looking at my dyno plot its obvious that a redline shifting will give the maximum amount of acceleration. Ill plug the numbers into the program a verify that a 6500 rpm shift point is optimum.

 

Ok...I just ran the numbers for a STOCK 2K 5 speed Maxima. These were based on my car's dyno plot when stock. I used a redline of 6500 rpm and the stock 17" wheels and tires (225/50/17 Potenzas).

GEAR/OPTIMUM SHIFT POINT/SPEED
1 / 6500 rpm / 36 mph
2 / 6500 rpm / 65 mph
3 / 6500 rpm / 95 mph
4 / 6500 rpm / 128 mph

Just for yucks, I ran this car in a simulated quarter mile (the program can do this as well) and it netted a 15.0 @ 94 mph, which is pretty close to what a stock 2k Max 5 speed can do. Top speed calculated to be 144 mph.

Ive got a dyno plot on a 1998 4th gen Max 5 speed here as well and Ill calculate the optimum shift points for that car next. Just by looking at it, its obvious redline will not be optimum.

[Edited by madmax2k on 12-30-2000 at 06:21 AM]

 

Heres the data for 1998 5 speed Maxima. These were based on a friend's dyno plot when modified with CAI, Y-pipe, exhaust. I used a redline of 6500 rpm and the stock 15" wheels and tires with 215/60 tires.

GEAR/OPTIMUM SHIFT POINT/SPEED
1 / 6440 rpm / 32 mph
2 / 6200 rpm / 62 mph
3 / 5940 rpm / 87 mph
4 / 5600 rpm / 110 mph

Again, I ran this car in a simulated quarter mile and it netted a 15.0 @ 94 mph. This exact same car ran 14.73 @ 94.1 mph last week, so I know the program is assuming a lower level of traction at the launch than this car actually acheived. But, the trap speed as predicted and as achieved is identical. Top speed calculared to be 137 mph.

Can anyone wh has made alot of runs verify that the above shiftpoints are optimum at the track for a 4th gen?

 

 

.

 

Its called CARTEST, and it rocks! Its a shareware type program thats free to use and download. All the author asks is that if you like it and use it, you send him $20. I liked it, so I happily sent in the $20! Its a great program. Ill have to dig up where I downloaded it from.

 

.

 

Don't read into the statement too much. If you look at a B16A, the torque begins to climb at around 6000 RPM, so the engine needs to be revved up so that the engine speed stays in that area when it's shifted in the next gear.

 

Actually, I knew exactly what you meant. But you have to remember that the 5th gen engine is a rarity due to the fact max HP is right around redline. So for best acceleration, shift at redline.

 

How bad is it for your car if you hit the rev limiter? It seems to be a problem for me when I race. The limiter is so close to the redline, it makes it hard not to hit...

 

Well, Ive hit the limiter at least 100 times and nothing happened yet

But, if you shift really fast, you can actually exceed the rev limiter by about 300 rpm without aqctually feeling the rev limiter hit. My revs usually spike to about 6800 rpm between shifts as the engine revs up a bit more as its unloaded between gears. Since theres no load on the engine for a brief instant, the computer doesnt seem to actually fuel cut.

 

U CHEATER

What I want to know is how do I keep the damn tires from hopping, its the most annoying thing.

 

Let the clutch out slower and give it more throttle.

 

Let the clutch out slower and give it more throttle. [/I][/QUOTE]

Well what about when they loose grip in 2nd? Also larry tell me something, why are the whells hopping, MY stock RE-92z didn't hop much, but these RE-730 do a lot, Why, b/c they are heavier, More grip? Wider? whats the reason? I've tried with 44psi, 40psi, 38psi, 36psi and now running 32psi and still they hop. a little less at 32psi but still do. just can't figure out why

 

MadMax-

I recently dynoed my 96 Max and found that shifting at 6100 rpms on the 2-3 and 6000 on the 3-4 would be optimum. The 1-2 should be done at near redline so that you land deep into 2nd gear. 1st winds out so fast the car doesn't "feel" weak after 6000 rpms. Last season when I was racing, I was shifting way too late because I didn't know what kind of power I was making. I was shifting at an indicated 6400 which is about 300-400 rpms too late. I've adjusted my shiftpoints accordingly and my shift light is set up to go off at 5900 rpms so that by the time I shift I'm at 6100 rpms, except for 1st which I'll take up to 6500. I hope to shed a few tenths now that I know where my power is. I may try powershifting too.


Dave

 

Here's the link:

http://home.earthlink.net/~patglenn/ct.html

[Edited by y2kse on 12-31-2000 at 02:30 PM]

 

Cool...If youve got the CarTest program, you can enter your actual dyno info and it will determine all kinds of performance info for you. If you dont have the program, send me your dynoplot, and Ill use that data and enter it and see what it says for shiftpoints, accelerations, etc, etc. We can even enter different air temps and pressures and see how it affects the outcome! There is also a friction factor that can be fooled with until a realistic 60 foot time is seen.
It looks like your dyno must have been very similar to my friend's as his calculated shift points according to the program came out very close to what youve stated.

Someone just posted the link to the program below if you wish to d/l it. Its slick...you can play with it for hours, and even race compettive cars against each other! You can change gear ratios, power curves, etc, etc, and see how the outcomes are affected.

 

you're doing nothing wrong to the car if you hit the rev limiter. it basically cuts the timing/spark and drops the rev several hundred RPMs for a split second.

 

I hit it and the hood release jamed.

 

Well what about when they loose grip in 2nd? Also larry tell me something, why are the whells hopping, MY stock RE-92z didn't hop much, but these RE-730 do a lot, Why, b/c they are heavier, More grip? Wider? whats the reason? I've tried with 44psi, 40psi, 38psi, 36psi and now running 32psi and still they hop. a little less at 32psi but still do. just can't figure out why [/I][/QUOTE]

If you are wheel hopping badly in 2nd gear then youve either got alot more power than I do, or you are on a traction limited surface.

When wheels are "hopping" the are alternately grabbing and spinning. Alot of this has to do with suspension geometry, which we could assume is fixed. Id guess if your RE-730 are hopping where your RE-92's didnt that the RE92's would have just spun in the same situation. But, I really cant see how a Maxima has enough torque to really wheel hop all that badly in 2nd gear. In any case, wheel hop is terrible on the drivetrain. It is the easiest way to blow out a tranny there is. So, try to avoid causing hop. Unless of course, you are in a race, and the Maxima's honor is at stake

 

Dude I've just started takeing easy on fast takeoffs. its the most annoying thing when the wheels are just hopping on dry pavement. I think its cold as heck out and the car is makeing more power then the wheels can grip. didn't do it a few months back when it was a little warmer. Tell me something else. in first gear, while just coasting at idle, and U stomp the gas, do both of your tires peel out and your car starts to scream or just one? b/c my car U hit it and the damn engine screams and it starts to spin both front tires until I lift, and it hits redline in a second, I mean I stomp and its bounceing of rev limiter WTF? is that the same with your car? I'll try holding down the RPM Steady at 5K and let the clutch out slow and see what happins. when I take off quick and shift into 2nd the wheels hop for a few and as the RPMs start to get up there they start to hop a little more by 3rd there's a small chirp and its done looseing grip.

 

Each of these shift points for the 2K max is beyond what the owners manual for my 2k1 SE 5spd AE max says is safe (i.e., max speed in 1 = 30, 2 = 55, 3 = 80). Is that not a problem? Could you run the same test on a 2K1 AE SE? I wonder if it would vary.