Taller top gear makes a real difference (10%)

[3dplane]

@Multiades! Hi! Nice writeup! I want to ask your opinion on this: I've got a 94 Protege
but mine is a DX with 1.8 SOHC. At 70 MPH it's turning about 2900 RPMs in fifth gear.

That already sounds a lot better than the LX however I still keep reaching for the shifter at 50+MPH to shift 6th gear but of course no more gears.

So I was thinking about the gear swap but from what I read it looks like I already got the kind of transmission that has the taller gears. What do you think based on the RPM reading above?

Btw I'm getting between 42-45 MPG if I'm driving like the rest of the idiots and has been as high as 53.5 MPG ( 3 times during summer ) if I'm putting around. No interstate speeds in my rout and lots of EOC.

Thanks!
Barna

[azgearhead]

Originally Posted by 3dplane

@Multiades! Hi! Nice writeup! I want to ask your opinion on this: I've got a 94 Protege
but mine is a DX with 1.8 SOHC. At 70 MPH it's turning about 2900 RPMs in fifth gear.

That already sounds a lot better than the LX however I still keep reaching for the shifter at 50+MPH to shift 6th gear but of course no more gears.

So I was thinking about the gear swap but from what I read it looks like I already got the kind of transmission that has the taller gears. What do you think based on the RPM reading above?

Btw I'm getting between 42-45 MPG if I'm driving like the rest of the idiots and has been as high as 53.5 MPG ( 3 times during summer ) if I'm putting around. No interstate speeds in my rout and lots of EOC.

Thanks!
Barna

2900 at 70 is pretty good. I was 3000 at 55. It sounds like you have to quit driving like the other idiots. My commute is 25 minutes on the interstate and 35 minutes on the road that follows the river. Which one do you think is more peaceful? On the slow route I can enjoy my coffee and occasionally see wildlife. Relax and smell the roses and save gas. Have you put extra pressure in the tires, this is not dangerous at lower speeds. Max pressure warnings protect traction and heat tolerence at high speeds, neither comes into play at low speeds. Low rolling resistance tires can be used at freeway speeds but the cost has to be justified by the fuel savings. Aero mods can help but have to be well thought out. Weight reductions have a bigger effect at speeds under 55 but can take away from comfort. My car has only a drivers seat and a cup holder in the interior. Weird but warmer and dryer than a motorcycle. If you want to be "stylin" just slow down the accelleration and be happy with the 53.5 you can get with a stock car.

[born2pdl]

Originally Posted by azgearhead

I found a real tall final ratio for my 2000 Metro, 3.28 vs 4.39. The difference in engine speed is 500 RPM at 55mph. The mpg is up 10% but is hard to drive above 55mph and maintain mpg. This ratio will allow me to realize real gains from planned weight reductions and aero-mods. This ratio is referenced on a 94 swift in Europe. I cannot find any other reference to it but am lucky that I found it.

So azgearhead, how about some more detail on your Metro final drive swap? Where and how did you get the parts? New or used? More detail on the drivability? I'm sure other metro owners besides me would be interested. Thanks.

[azgearhead]

I went to a used parts guy in Iowa to buy a trans with 3.54 gears and to my surprize it had 3.28 gears. Better to be lucky than good. Drivability is good but mpg gain is only below 55 mph. It runs well at higher speeds but is using too much gas due to wind resistance. I have many ideas to reduce weight but this involves butchering the chasis, not what most people want to do. This car is too heavy to get much past 55mpg with the stock and old engine (258,000 miles on the odometer) the original owner drove 120 miles per day. I think of my car as a warm and dry motorcycle. I am not concerned about comfort and chash protection. Drive slow, visible and predictable, save gas, live long and relax.

[3dplane]

@azgearhead: Wow 3000 rpm at 50MPH is pretty crazy! I hope that was before the gear swap!
About the weight...I would only worry about that if I had a lot of stop and go
traffic. ( I don't) As a matter of fact I noticed with my car that if I have some
extra weight on board,it coasts a lot longer and gets me over small hills where otherwise I would have to restart my engine. Even after fill up it's noticeable.
Of course during acceleration the extra weight hurts MPG but my rout is mostly highway. Just my experience..: )

[azgearhead]

Extra weight helps you coast up hills?

[3dplane]

@azgearhead: I don't want to get too much off topic but for you,let me
quote myself: "gets me over small hills" . Meaning if I start coasting on a long
slant downhill that is interrupted by a small uphill and continues downwards,
the momentum carries me over the uphill part only when my car is heavier.
When light,I have to restart my engine because I never built up enough speed
on the initial downhill to make it over the small hill.
So using your conclusion yes! Extra weight helps me coast uphill!

[azgearhead]

I understand completely now. I remember the pinewood derby cars in cub scouts had to have the maximum weight to go downhill the fastest. In this case, my experiences reinforce yours. I didn't give you a chance to explain and my mouth got ahead of my brain. I have been working to reduce that tendency for 58 years to no avail. Sorry. I would like to hear more about your hypermileing.

[3dplane]

@azgearhead: No problem,we all have our moments and that must have been your moment : )

My hypermiling consists of all the simple common sense driving techniques that
are listed on this site like: Being smooth with that right foot, engine off coasting when ever possible, driving with load , not using A/C, watch traffic way ahead ( and behind ) etc.etc.

We shouldn't really be chatting off topic in this thread though : )