80MPH at 3400 RPMs?
10-20-2008, 09:27 AM
#1
80MPH at 3400 RPMs?
Hey does this sound right? I have a 5 speed. I just cleaned the throttle body, new air filter, and a new PCV valve. I didnt clean the IACV or change the fuel filter could that be why the RPM's are so high?
10-20-2008, 09:31 AM
#2
Physically impossible for that to cause a change in your tachometer reading. The speed / RPM is mechanically governed by things like wheel size, transmission ratio, etc. The ECU is programmed with the speed vs. RPM and will not change.
80mph/3400 sounds about right.
What size tires are you running, and on what rims?
80mph/3400 sounds about right.
What size tires are you running, and on what rims?
10-20-2008, 10:17 AM
#6
Yep its normal, wheels will not affect the engine speed reading from the tachometer. It might not be 100% accurate, I know that mine reads about 100rpms higher than it actually is revving, due to having a VAFC-II.
It does suck that our 5th gear isn't taller but oh well, I still get 27 mpg if I drive easy on the pedal and all highway.
It does suck that our 5th gear isn't taller but oh well, I still get 27 mpg if I drive easy on the pedal and all highway.
10-20-2008, 11:15 AM
#11
Is there a reason Nissan didn't make 5th taller? It spins pretty dang fast, it gets annoying when you're out in the middle of nowhere and are cruising at 85-90 like everybody else.... My mom's 00 I30 is a good bit slower, which seems a bit counter intuitive, does it not?
While we're on the topic, how do you guys feel about the ratios of the 5 speed? That is, is first too short compared to how long second is, etc..
While we're on the topic, how do you guys feel about the ratios of the 5 speed? That is, is first too short compared to how long second is, etc..
10-20-2008, 01:56 PM
#13
It's a maxima, not a ferrari. I think the ratios are just fine.
I suppose a taller 5th might help fuel economy, but if you need to push hard on the gas in 5th to accelerate you can pretty quickly eat up the fuel savings that you saved while cruising.
Dave
I suppose a taller 5th might help fuel economy, but if you need to push hard on the gas in 5th to accelerate you can pretty quickly eat up the fuel savings that you saved while cruising.
Dave
10-21-2008, 05:30 AM
#15
with a lightweight flywheel my car now cruses just about 3050 rpm @ 80. I believe nissan designed the fifth gear so that you wouldnt have to downshift at highway speeds to pass, as the torque curve on the vq really kicks up around 3000 rpm
10-21-2008, 06:07 AM
#16
i know i'm in the wrong forum, but the 3g 5spd is basically the same way. pulls good in 5th but screams along at an even higher RPM than the 4th gen 5spd... i'm turning 3000 at like 75mph. so what i'm planning to do is replace my 5th gear (in/out) with the correlating parts out of a 2nd gen transmission, to give me a longer 5th gear (.745 instead of .790). if any of you are handy rebuilding manual trannies, this may be a direction some of you will want to look into, providing that the VG tranny parts will match up to the shaft splines on a VQ tranny.
10-21-2008, 08:07 AM
#21
but currently i lose 33% rpm from 3 to 4, and a scant 20% from 4 to 5....... using a 2nd gen 5th would drop me by 29% into 5th which is much more comfortable.
10-21-2008, 08:27 AM
#22
4th generation 5th gear ratio
Please post what most economical solution to 5th gear ratio reduction!
I wonder if replacing entire tranny with "lower RPM" box out of another Gen/Altima is the least expensive or getting gear to match current tranny... either way, labor costs will make this a *#&**$$$. I agree, that our VQ does NOT need such a high RPM "cruise gear" as it easily passes traffic in 5th gear below 3K!! If you need to "blast around someone" pull it back one gear! My auto has perfect OD gearing and cruises at below 3K (30MPG) at 75/80... I NEVER have to downshift out of OD to easily pass.
I wonder if replacing entire tranny with "lower RPM" box out of another Gen/Altima is the least expensive or getting gear to match current tranny... either way, labor costs will make this a *#&**$$$. I agree, that our VQ does NOT need such a high RPM "cruise gear" as it easily passes traffic in 5th gear below 3K!! If you need to "blast around someone" pull it back one gear! My auto has perfect OD gearing and cruises at below 3K (30MPG) at 75/80... I NEVER have to downshift out of OD to easily pass.
10-21-2008, 09:47 AM
#23
It's not a simple answer. It would require some calculations using the engine fuel usage vs. load vs. rpm characteristics to determine what the optimum would be.
It is probably more economical to have a taller fifth, since the fuel economy testing of 1993-94 were based on a "highway" speed topping out at 60mph. (http://www.fueleconomy.gov/feg/fe_test_schedules.shtml)
Most of us drive on highways much faster than that. The optimum overdrive ratio will change if designed primarily for 75mph.
All that said, changing 5th will require that the synchros be compatible and the splines line up. I have several spare 5ths and shafts laying around from a 4th gen, but I don't have any altima or 2nd gen maxima parts. It's entirely possible that the parts are a drop in just like the 3rd gear from an altima is. If someone had the proposed gear parts handy we could figure out if they will fit.
The trouble with this exercise is that if you're paying a shop to change it you'll never recover that cost in fuel savings. Even if I'm doing a rebuild for someone and the labor is a non-issue, I still need to have the spare gear parts hanging around or bastardize a core. So that further adds to the cost and difficulty.
Dave
It is probably more economical to have a taller fifth, since the fuel economy testing of 1993-94 were based on a "highway" speed topping out at 60mph. (http://www.fueleconomy.gov/feg/fe_test_schedules.shtml)
Most of us drive on highways much faster than that. The optimum overdrive ratio will change if designed primarily for 75mph.
All that said, changing 5th will require that the synchros be compatible and the splines line up. I have several spare 5ths and shafts laying around from a 4th gen, but I don't have any altima or 2nd gen maxima parts. It's entirely possible that the parts are a drop in just like the 3rd gear from an altima is. If someone had the proposed gear parts handy we could figure out if they will fit.
The trouble with this exercise is that if you're paying a shop to change it you'll never recover that cost in fuel savings. Even if I'm doing a rebuild for someone and the labor is a non-issue, I still need to have the spare gear parts hanging around or bastardize a core. So that further adds to the cost and difficulty.
Dave
10-21-2008, 11:55 AM
#24
I guess the reality of my question is: gears/tranny swapping "not even practical" until tranny is ready to be re-built! At that time the specs of each transmissions' gear offerings to gain "optimum" gear selections could be factored. However, really all I want to get is a 5th gear replacement on my 4th gen 5speed that was much lower RPM (a real O.D. drop).
Yet, I realize that even if someone had such a 5th gear-conversion tranny made-up or replacement/crossover tranny w/desired 5th gear ratio just laying around, I'd have to wait for tranny R&R-time labor $$ to make sense...
and not really wishing it to be soon! Even though I want that gearing!!!
Yet, I realize that even if someone had such a 5th gear-conversion tranny made-up or replacement/crossover tranny w/desired 5th gear ratio just laying around, I'd have to wait for tranny R&R-time labor $$ to make sense...
and not really wishing it to be soon! Even though I want that gearing!!!
10-21-2008, 12:24 PM
#25
6-speed
If you are going through all this trouble to make a better 5-speed, why not swap a 6-speed. Not practical for Capedcadaver, vg, not vq, but for everyone else... I know it is work to go from rod to cable, but designing a transmission is also pretty tough
10-21-2008, 01:06 PM
#26
But even so it may be possible for me to do that on my current engine, with a bellhousing adapter, if I ever learn how to weld and fab metal things. i thought there was a sticky for the 6spd conversion somewhere, right?
10-21-2008, 01:46 PM
#27
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Join Date: Sep 2008
Location: N.H
Posts: 62
at 80 mph my rpm is at 3000 steady, i have an outo tho.
10-21-2008, 01:51 PM
#28
yea.. my old VG A/T would run 85mph @ 3000 on a tach that read high so more like 2900... but the manual has shorter gearing to make up for the fact that you don't have a TC allowing a few hundred RPMs of slip when out of lockup mode.
10-21-2008, 04:41 PM
#31
And that's disappointing, I've never bothered to get top speed cause it takes too long. Guess I just gotta pack some more power.
^^ horsepower, not torque, .>>> semantics.... but I have to agree, I think we all wish Nissan had put some more thought into the Max tranny, then again, gas wasn't such an issue back then, and the mileage it was getting in it's day was very impressive by those standards. 6 speed would have been perfect.
Last edited by TunerMaxima3000; 10-21-2008 at 04:43 PM.
10-22-2008, 10:24 AM
#36
yea... that's why i was wondering where he got that idea..... i just swapped in a light flywheel and the only difference is the performance... so unless he put on a differently-geared tranny (if any such differently-geared 5spd will even fit a VQ maxima) then he must just be mistaken or have a bad tach or something.
10-22-2008, 04:47 PM
#38
Senior Member
Join Date: May 2008
Location: Martinsburg, WV
Posts: 239
ooohhhh another mustang guy. The speeds sound about right. They are totally different than our stangs. Check out my babies below...
