Are mainstream cars geared too tall?

[fdcg27]

Why do some cars feel so dead at highway speeds, while others of similar weight and output are quite lively?
I think the primary difference lies in overall gearing.
For example, compare my 318i with my friend's G5.
Pretty similar in weight and power, with virtually identical fuel consumption in actual use.
At higher speeds, the BMW is lively and strong, while the G5 is slow and weak.
The difference?
Overall gearing.
The BMW is geared much shorter than the G5.
The G5 was optimized for good fuel consumption and quiet operation, while the BMW was developed and geared for driving fun.
In the same vein, the '97 Accord is more relaxing to drive than the more powerful '99.
It is geared significantly shorter, and therefore requires fewer downshifts to maintain a decently fast pace.
My old MGB, as well as our old '76 Civic, were quite lively at higher speeds, despite having low power, because they were geared quite short.
I am of the opinion that most cars are geared too tall.
This is fine for cruising along, but becomes bothersome when you want or need some acceleration at higher speeds.
Forget downshifting, as there is often not a suitable ratio available, especially in the slushboxes.
I also think that any difference in real-world fuel consumption is minimal, contrary to any EPA test results.
What do all of you think?

 

[rslifkin]

With an average 4 cylinder (powerband in the high rpms), I'd agree. My sisters 94 Camry, like the 2000 Hyundai Elantra I used to have, is gutless below 70 on the highway, and prefers to run 75 - 80. Below that, the gearing is too tall to keep the engine anywhere near it's powerband, and it downshifts constantly. At 75+, it never downshifts.

My Jeep, however, is the exact opposite. It's geared lower than it needs to be. It turns just over 1800 at 60mph, and regardless of speed (anywhere from 50 - 75+), I have yet to find a hill it can't accelerate up in OD with the TC locked. It turns much lower rpm on the highway than an average 4 cylinder, but has so much torque that it could be geared a little taller, still not need to downshift, and probably get 1 - 2 mpg better at 60 or so.

 

[FL_Rob]

I know older Gm's are notorious for this .I routinely drive in D rather than OD .The rearend is 3.08 which is really too tall for a full size van around town but at 70 to 75 it's ok.If I drove like everyone else around town, my clutch packs wouldn't make it a month.

 

[Johnny248]

Is't a G5 an Ecotech 4? and a 318 is an i6?

 

[-Clayton-]

I don't know about cars as I haven't driven many newer ones but trucks definitely are. My 4.2 5 speed f150 has 3.55 and it's just ok, Some have 3.08's. I plan on regearing it to 4.10 later this year, Should wake it up nicely.

 

[rslifkin]

A BMW 318 is a 1.8 liter 4 cylinder. A 323 or 325 would be an I6.

 

[Russell]

Generally I think you are correct regarding the gearing. My BMW 525i with 4 speed auto (4th is overdrive)runs stronger the faster you go as it gets into the powerband above 3,000 rpm even with short gearing. Forget the gearing. Heavy car with 2.5 liter 189 hp engine. Still gutless at low rpm with current gearing.

To partially compensate, BMW has a sport mode with the 4 speed automatic. No overdrive and higher and firmer shift points. Great for around town and lower speed curvy rds.

 

[bruno]

That's what transmissions are for !
Downshift !

 

[Eddie]

+1. That is why I have a shiftable Automatic. My top gear is good for crusing and fuel mileage.

 

[XS650]

Originally Posted By: Eddie
+1. That is why I have a shiftable Automatic. My top gear is good for crusing and fuel mileage.


+2 If you have strong throttle response at cruise you are operating off the most efficient part of the BSFC fuel map for the amount of power needed for cruise at that speed.

 

[Quattro Pete]

Exactly. If you feel there isn't enough passing power, just downshift a gear.

 

[IndyIan]

+3
This why there is now 5 and 6 speed automatics offered. My parents CRV has a 5 spd auto and downshifts alot on hilly 55mph roads but it should get better mileage on flatter faster roads with the higher top gear.
I don't know why more manual cars don't have 6 spd transmissions with a high overdrive. That way you can use 6th for 70mph+ and 5th for regular driving.

 

[Captain_Klink]

that's one of the nice things with the Subaru Impreza, 2.5 NA, it cruises at a slightly higher rpm, which sacrifices a bit of mileage, for readily available power. now they have a CVT, and mileage goes from 27 to 31 mpg, about 10% better, but you're driving now with less instantaneous power.

 

[fdcg27]

I have driven mainly sticks for the past thirty years or so, so I am familiar with downshifting.
Having to change down a gear or two is not nearly as satisfactory as having power available with a twitch of your right foot.
Also, there is not always a suitable ratio available, a particular problem with slushboxes, even those that are pretend manuals.
For two lane passing, you would of course select third.
On the interstate, it is a convenience not to have to do so.
Drive a fairly short geared car for a while (BMW 318i, 22mph/thousand in fifth), and then try a tall geared one ('99 Honda Accord, 27mph/thousand in fifth).
See which one you prefer, and you'll then understand where I'm coming from.

 

[mechtech2]

Tall highway gearing is generally a great idea [in high gear or lockup].
Downshifting is the key. Going too fast to downshift? Then you simply have a weak engine or a heavy vehicle. It is what it is.

I would rather cruise with tall gearing and less manifold vacuum - more efficiency and less work to try and maintain vacuum.

 

[JHZR2]

Most people are lazy, thus they buy automatics. An auto will go out of lockout mode or drop a gear pretty quick/readily. I don't see the issue there.

What annoys me is, for example, my friend's 07 matrix. !st gear with the electric throttle tip-in is so severe to make the car feel fast, that it is annoying to me to drive.

 

[fdcg27]

I know what you are saying.
However, the difference in actual fuel use is minimal.
The difference in sound level is real, though.
There are some engines I really wouldn't want to have to listen to for very long at higher revs, while there are those that are smooth and pleasant.
I would not want to listen to an Ecotec at four grand for very long, for example.
Fortunately, the BMW is smooth and pleasant in its note.

 

[ItsuMitsubishi]

Highway cruising on DBW cars is a different ballgame. Some of them crack the throttle a bit more, and fully retard the cam timing kind of like a bootlegged atkinson cycle. Some also go into crazy lean burn modes. Tipping in the pedal requires the fuel trims to change drastically and the cam phasers to return to a higher vacuum position before you can feel any kind of response. Sometimes tumble and swirl controls are thrown in there too. That combined with super tall OD gearing will make most people really notice. In this day, it's all about bragging (marketing) the highest peak horsepower WITH the highest highway fuel economy. New engines simply run a much wider range of operation, which really kills engine response.

The M40/42 4 cylinders are nice engines, old school design. I remember driving one a years back, it was nice, revvy. Seemed like it would take boost very well.

 

[BearZDefect]

IMO, the tall gear ratios in today's mainstream cars are fine for flatlands. For hilly terrain they are a nuisance at best.

 

[CBR.worm]

I agree that gearing can make or kill a car.

What kills me is I am at the opposite end of the spectrum.

My G35 has a 6 speed stick and in 6th gear on the highway I am at 3,500 rpm or higher for hours a day. Yet 1st gear is not particularly low, the gears are very close together. I would prefer wider ratios and an overdrive gear or two. I can barely get 23 mpg on the highway.

My wifes bigger heavier BMW turns about 1,000 rpm less at 85 and gets 30 mpg. It is geared low enough that it still pulls well on the highway.