When I am just cruising I like to put it into 6th as soon as I can, to help with mpg. Once I am up to speed, I will put it into 6th at as low as 40mph. I just wanted to make sure that I'm not doing any damage. The RPMs are about about 1500. When I need to accelerate or go uphill I always down shift. I try not to run at higher PRMs than needed, but is there such as thing as running at to low an RPM?

 

as per the owners manual, I will shift as low as 38mph, thats actually their "recomended shift point". I guess thats how they get such good gas mileage. I forgot to put the clutch in once when stopping, did about 15 in 6th, the engine didnt seem happy, it was shaking a lil bit. as soon as it was noticable, I corrected myself.

 

I remember reading that too, and at the time I read it, I thought it seemed a little too low, but it seems to work. When I am closer to 40 the engine seems to not quite be as smooth as normal. When I get up to 50 it seems to get back to normal.

 

How can you run at 40mph in 6 gear and claim to have any control? If you need to speed up to avoid something, you're screwed. Running your gears at 2500-3000 cruising rpms not only won't harm your car, it's safer.

 

The only aspect of control that I am giving up is accellerating. Typically I don't have much of a need for any emergency accelleration. Emergancy breaking maybe, accelerating no. When I am on roads with traffic I usually stay in lower gears for manuevering purposes, but most of the roads I end up on are pretty empty, and as for the few cars that are on the road I just keep an eye on them. So when I don't need extra power, whats the point of being at higher RPMs. It just wastes gas.

 

i usually put it into 6th at 45 if I know im going to be going above 45 for awhile....otherwise I leave it in 5th if im going 30-45

 

To me, the car feels to sluggish below 2000 rpm. Cruising at 45 mph I MIGHT be in 3rd gear. Does anybody out there know if you can damage the car by running in too high a gear?

 

There is no such thing as "light traffic" in the Seattle area (actually I live on the East Side (Bellevue, Redmond, etc.) and work in Tacoma). So you very rarely get a road by yourself.

I almost always drive in 3rd gear at speeds up to 35mph. Once I start approaching 40, I'll use 4th gear. I very very rarely use 6th on highway driving to and from work. I need the acceleration, which means I usually end up driving most of the way to/from work, on the highway at 65-75mph, in 5th gear (except for the occasional 4th gear pass... :-).

 

LOL! Two completely different ways of driving! I don't much like 6th gear; not enough torque! I rarely get into it until about 80, or maybe if I'm cruising for a long way at 70.

Running a car at too high a gear is called "lugging" and it''s not good for the car if you do it a lot but I doubt you can do much immediate damage from doing it one time. Think of it this way: the entire weight of the car is refusing to allow the piston to go down as fast as it needs to after the spark plug fires. You really need to get extreme with it to hurt the car, though, and you will hear and feel it complain.

I haven't played with it much (never wanted to or was able to force myself to do so) but I think the RPM speed of lugging depends on how much gas you're giving it. If you're coasting it doesn't lug until you get idle speed or below, but if you try to accelerate at too low an RPM you will feel/hear it lug at higher than idle RPM.

FWIW

 

There is not such thing as running too high in RPM, but remember this little rule: avoid "constant" rpm's higher than 80% of the max rpm. So 80% of 6600= 5280.

But seriously, don't tell me you guys bought this car to run a "low gas mileage"??? It's a sportscar!!!
It runs a lot smoother in higher rpm's. I agree with davidh, I try to stay above 2500 rpm. The car feels better and SOUNDS better.
If I wanted a good mpg, I would buy me a VW Golf Diesel...

 

Trust me, I do understand that it is a sportscar, and I do get the most out of it, but you can't be accellerating all of the time, and when I am not, whats the point of being in a lower gear. Its easy enough to downshift when I need to pass someone, or when I just want to have fun. I just want to make sure I am not hurting the car when I am at low RPM. From what it sounds like everyone is saying, I wont do damage, but it will be smoother if I keep it a little bit higher. I can deal with that answer.

 

I drive with other cars... and even shifting like a granny at 38mph, I can accelerate just fine... no Im not winning any indy races in 6th gear, but what do I need 3rd for? so I can run into the civic in front of me faster?

I definitly get on the car when I feel like it, and when I do, Ill never hit 4th gear. but for regular driving, I dont need emergency acceleration.... thats just silly.

 

manual recommends for normal acceleration at around 2K RPM. I mean there's still power around 1,700 RPM's... can still accelerate at a modest speed. By 35mph and cruising, i go to 5th. at around 45mph is when i go 6th. For me, in California.. i try to save gas whenever i can. freagin $2.05 a gallon for Premium

 

Jeez, no wonder I never got over 20 mpg. The only times I've ever used 6th was during break-in (re the manual) and several times at 100+ mph. I usually cruiZe at 3000rpm, but have never had it much over 4000rpm (except when I missed a shift a couple of times). I thought the shift points listed in the manual were typos, a Nissan joke, or accidentally cut and pasted from the Sentra manual.

 

You mean we have more than 4 gears in our cars? 4th is good to about 120 I think. Gas Mileage wtf is that???????

 

Paul Frere (and Phill Hill) in "Sports Car and Competitive Driving" recommend as follows:

"For minimum wear and tear the engine should also be kept in the middle revolution ranges, but not given full throttle on a high gear unless it is running at least at one-third of its maximum rotational speed, when the inertia forces partly offset the high gas pressure resulting from full throttle operation, transmitted to the bearings by the pistons and connecting rods. Very high rotational speeds will, however, result in very high inertia forces (which increase with the square of the rotational speed) with consequent high stresses on all moving parts. Slogging or hard pulling at low revolutions not only produces very high gas pressures but also may result in burnt valves while gas at high temperatures is laminated through them as they open and close comparatively slow."

I'm not sure if variable valve timing resolves this problem, but I'm going to follow the advice.

So, IMO, drive in the mid rpm ranges - about 2,100 to 4,200 rpm whenever possible or convenient.

 

bfleming, thanks for that info. It sounds correct and confirms my suspicion that driving in to high a gear (very low rpm) can damage the car. Cruising between 2200 and 4000 is where it soundZ and feelZ the beZt. Happy driving.

-davidh

 

I don't think that is exactly what it said. What I took out of the quote is not to floor it in at low RPMs. I don't see it implying that cruising at low RPM is a problem. I also think no one seemed to claim to be using a high gear for accellerating. That is why we downshift. I think the fact that the manual suggests the shift point to go into 6th is 38 mph is much more sugnificant. But its your car and you can follow what ever info you like.

 

sherman,

point taken. happy driving!

-davidh

 

I've got the SpecV and I don't know what the manual says buy 38 in 6th is ALMOST lugging. 35 IS lugging. Cruising at 40 in 4th gear is about 2300 - 2500 rpm and sounds good at that point.

And I don't remember where I saw the thread but I've seen pics of a main bearing ruined by high rpm as opposed to lugging. They have distinct differences in the type of wear done. Lugging a motor will kill it if you do it long enough...