When measuring the power needed to ascend a hill....

[Fenixgoon]

power = force*velocity

the force you need to overcome on a hill includes (gravity, rolling resistance, etc.). velocity is the speed you want to go.

this problem is should be covered in any basic physics textbook.

 

[fleabag]

So you swap your transmission and get the ideal RPM for max gas mileage for that hill... what happens when you get to a different hill?

lol. I'm not looking for the most ideal RPM for this hill, I just don't like the idea of being in 1st gear in order to ascend this hill. 4000rpm is just too high but something between 2 and 3000rpm would be alright.. This is the tallest hill I have to ascend on my commute so all other hills (if I can do this one in 2nd gear) would also be in 2nd gear or higher.

 

[BlackTigers]

lol. I'm not looking for the most ideal RPM for this hill, I just don't like the idea of being in 1st gear in order to ascend this hill. 4000rpm is just too high but something between 2 and 3000rpm would be alright.. This is the tallest hill I have to ascend on my commute so all other hills (if I can do this one in 2nd gear) would also be in 2nd gear or higher.

Oh, my god.

The difference in gas, on that hill, between 2600 and 4k rpm, will be MINIMAL....not even worth figuring it out.

Why do you not want your mom's car to hit 4k rpm? Is it too loud for you? lmao.

 

[fleabag]

Oh, my god.

The difference in gas, on that hill, between 2600 and 4k rpm, will be MINIMAL....not even worth figuring it out.

Why do you not want your mom's car to hit 4k rpm? Is it too loud for you? lmao.

It's actually my car, but thanks for playing... Anyway the hill is about 1/2 mile long and 2500rpm vs 4000rpm could mean the difference between 8mpg and 12mpg which is actually quite a measurable difference!

 

[coxmaster]

It's actually my car, but thanks for playing... Anyway the hill is about 1/2 mile long and 2500rpm vs 4000rpm could mean the difference between 8mpg and 12mpg which is actually quite a measurable difference!

Why dont you take out the spare tire, and all of the rest of the interior.. You should probably start on a diet too. Save weight! SAVE GAS

 

[DivideBYZero]

The exercise of exchanging the transmission and this thread are both beyond pointless.

Learning experience? Yes. Worth it in any other tangible way? No.

 

[LTC8K6]

1st gear? What are you driving up, a cliff? Or is your clutch slipping? The one in the car, I mean...

 

[thomsbrain]

First, I would never bother doing this.

Second, if you DID do it, I wouldn't see any problem since the VX you'd be pulling it from already makes LESS power than the LX you want to swap it into. So even with the taller gears you'd still be better off than the original car it came from, and Honda was okay building that car. I'll hedge a bit by noting that the VX was a fair bit lighter than the LX, but even so I think it would be fine.

 

[Kirby]

The exercise of exchanging the transmission and this thread are both beyond pointless.

Learning experience? Yes. Worth it in any other tangible way? No.

I wish he would do it, as long as there is video. I can just imagine him driving up the hill, transmission falls out, rolls down the hill and kills his dog, tires explode, and his mom beats the shit out of him for fucking up her car.

 

[PhoKingGuy]

Labor would actually be inversely valuable because this would be a learning experience. But yes you're correct in that going from 40mpg to 45mpg and driving 7500 miles annually I'd save maybe $63 in fuel. However, I believe the gains should be higher than that or at the very least make my life easier because I wouldn't have to shift so often. Also while the gains on the highway may not be as high as I'd hope, I think I can average around 48/50mpg on the highway cruising at 53/55mph with the current transmission, the real gains would be made in the city where I'd be improving the 32/35mpg city average and bringing it up to the 40s.

My main goal is to have a car that averages 50mpg when commuting to my gym. Once I achieve that goal, I'll be able to start going to the gym again.. There are a few other things that I'll be able to do once I achieve the 50mpg mark. 50mpg combined is going to be difficult but not impossible. Either way, I know I'm going to put in another transmission, the question is will it be the HX or the VX transmission. Since the VX has much lower gearing and is cheaper to purchase, I think I'm going to go with that first, but if I find it to be too tall, then I'll use the HX transmission.

There is also another fringe benefit to using these taller transmissions. I won't have to hear the engine "scream" while on the highway, instead of cruising at 2246rpm/2650rpm (55mph/65mph), I'll get a quieter engine that will be cruising at 1799rpm/2126rpm (55mph/65mph).

Christ man the rigs go faster than that

 

[PricklyPete]

My main goal is to have a car that averages 50mpg when commuting to my gym. Once I achieve that goal, I'll be able to start going to the gym again.. There are a few other things that I'll be able to do once I achieve the 50mpg mark. 50mpg combined is going to be difficult but not impossible. Either way, I know I'm going to put in another transmission, the question is will it be the HX or the VX transmission. Since the VX has much lower gearing and is cheaper to purchase, I think I'm going to go with that first, but if I find it to be too tall, then I'll use the HX transmission.

I'm not understanding this...you are not allowing yourself to go to the gym until you figure out how to get there with a minimum 50MPG? Huh?

 

[bruceb]

Not sure about the grade. I used to live up there about 5-6 years ago. It is fun to drive it coming up from Oakland, but you need to slow down as soon as you get on the downhill.
Cops like to sit after Conklintown Road to catch the cars coming down the hill. Going back toward Oakland, a nice long uphill, then some nice twisties after you pass the park. It sucks when you get behind a slow car. Watch it as you near the RT287 overpass for an Oakland cop car.

 

[IcePickFreak]

If your "main goal" is 50mpg when traveling to the gym, why not ride a bicycle to the gym? You'll see some very tangible benefits outside of no consumption of gas at all, such as less time needed at the gym which could also possibly lead to lower membership fees.

 

[ElFenix]

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[quakefiend420]

If i ever see you out and about in Ausitn, I'm going to run over your civic with my truck that gets 8mpg.

 

[Evadman]

It's actually my car, but thanks for playing... Anyway the hill is about 1/2 mile long and 2500rpm vs 4000rpm could mean the difference between 8mpg and 12mpg which is actually quite a measurable difference!

I can't find anywhere in this thread about how often you drive on the hill, but I do see that you drive 7.5k per year, and the hill is on your commute. Let us therefore assume that you drive on the hill twice per day (one up one down), 5 times a week. Let us further assume that you can bring the gas mileage from 32 to 40 mpg in the city like you state. Let us also assume that you will keep the car for 10 years after the swap. Also, let us asume that your current mileage on the 1/2 mile hill is 12 MPG (in second) and final is 8 MPG (in first) like you also state. Let us make one final assumption that you are not talking out of your ass.

That means you drive up that hill: 5 days a week * 0.5 mile per day = 2.5 miles per week, or 130 miles per year for 10 years. A total of 1300 miles in first gear instead of second. That is 108.3 gallons at 12 MPG vs 162.5 at 8 MPG. So over 10 years, you will buy 54.2 more gallons. With gas at $3 a gallon (premium of course for you) you will buy $162.6 more dollars of gas over 10 years. That is 4.45 cents per trip up the hill in first instead of second, or 0.014 gallons of gas difference between 1st and second.

Your current trans has a full ratio in 2nd of 1.762 * 4.058 or 7.150 total.
New trans is 1.761 * 3.25 or 5.723 total.

You also state you are at 2650 RPM at 65 MPH with a total drive ratio of 2.848. That is 930.47 revolutions of the tire per minute at 65 MPH. That puts the effective circumference of your tire at 5.674 feet. That means the distance from the ground to the center of the axle is 1.81 feet. Assuming zero deformation under weight load (which would make your tire as short as possible mathmaticly), that puts your absolue minimum installed height at 43.44 inches, but assuming some normal deformation, it is about 44.5 inches or so installed height. Sounds perfectly normal for a civic. Do you use TSL's to keep down road noise? That puts your door sill more than 2 feet from the ground. Do you keep a step stool in the trunk? How do you reach it in the trunk when the trunk latch by itself is 49 inches from the ground?

Since you say 2600 is screaming and what you are trying to avoid, but 2100 is not, let us assume you currently go up the hill at 2100 RPM in 2nd. With a full gear ratio of 7.150 in 2nd, and an effective diameter of 5.674 feet, you are currently going up the hill at 293.70 tire revolutions per minute, or 1666.43 feet/min. That is 18.93 MPH. With the new transmission at 2100 RPM the tire would be turning 366.94 revs per min or 2078.95 feet/min. That is 23.95 MPH. I would like to point out that if you go this slow, you are a douchbag. In a civic. With 44" tall tires. But that is besides the point I suppose.

You don't mention the grade of the street you are on, but the steepest in the continental us is in Pittsburgh at 37% I believe. (there is one in HI that is steeper IIRC, but you can't drive a civic on it.) 37% is 37 feet vertical per hundred horizontal. At a 1/2 mile like you state, you would be 976 feet (297.48 M) higher at the end than the beginning. Your civic is 1045 KG. In a perfect world, that is 3049650.55j of energy. That is 728 Calories, or roughly what is in a double quarter pounder with cheese from mcdonalds.

Since you are driving at 18.93 MPH (1665 ft/min) on a 1/2 mile hill, you will cover the 2640 feet in 1.584 minutes. Your car needs to do 3049650.55j of work in 1.584 minutes. 1 HP is equal to 2,684,519.54 joule per hour or 44742.0j per minute. Since you have 1.584 minutes to do the 3049650.55j of energy, you need to do 1,925,284.44j per minute. That equates to you currently using 43.03 HP in 2nd gear at 2100 RPM.

Using your new transmission at 2100 RPM, you would cover 2107 feet per minute and cover the required distance in 1.25 minutes. That means you need to do 2,439,720.44j per minute. That is 54.52 HP.

I forget where I am going with this and I don't feel like doing any more math, but the summary is you have no clue what you are talking about.

If i ever see you out and about in Ausitn, I'm going to run over your civic with my truck that gets 8mpg.

I would pay to see you drive over a civic with 44" tall tires. You would need to be bigfoot.

 

[jlee]

I don't understand, can you not visualize the swap or something???

Post pictures of the transmission swap when you are done.

Is that better?

 

[DivideBYZero]

I can't find anywhere in this thread about how often you drive on the hill, but I do see that you drive 7.5k per year, and the hill is on your commute. Let us therefore assume that you drive on the hill twice per day (one up one down), 5 times a week. Let us further assume that you can bring the gas mileage from 32 to 40 mpg in the city like you state. Let us also assume that you will keep the car for 10 years after the swap. Also, let us asume that your current mileage on the 1/2 mile hill is 12 MPG (in second) and final is 8 MPG (in first) like you also state. Let us make one final assumption that you are not talking out of your ass.

That means you drive up that hill: 5 days a week * 0.5 mile per day = 2.5 miles per week, or 130 miles per year for 10 years. A total of 1300 miles in first gear instead of second. That is 108.3 gallons at 12 MPG vs 162.5 at 8 MPG. So over 10 years, you will buy 54.2 more gallons. With gas at $3 a gallon (premium of course for you) you will buy $162.6 more dollars of gas over 10 years. That is 4.45 cents per trip up the hill in first instead of second, or 0.014 gallons of gas difference between 1st and second.

Your current trans has a full ratio in 2nd of 1.762 * 4.058 or 7.150 total.
New trans is 1.761 * 3.25 or 5.723 total.

You also state you are at 2650 RPM at 65 MPH with a total drive ratio of 2.848. That is 930.47 revolutions of the tire per minute at 65 MPH. That puts the effective circumference of your tire at 5.674 feet. That means the distance from the ground to the center of the axle is 1.81 feet. Assuming zero deformation under weight load (which would make your tire as short as possible mathmaticly), that puts your absolue minimum installed height at 43.44 inches, but assuming some normal deformation, it is about 44.5 inches or so installed height. Sounds perfectly normal for a civic. Do you use TSL's to keep down road noise? That puts your door sill more than 2 feet from the ground. Do you keep a step stool in the trunk? How do you reach it in the trunk when the trunk latch by itself is 49 inches from the ground?

Since you say 2600 is screaming and what you are trying to avoid, but 2100 is not, let us assume you currently go up the hill at 2100 RPM in 2nd. With a full gear ratio of 7.150 in 2nd, and an effective diameter of 5.674 feet, you are currently going up the hill at 293.70 tire revolutions per minute, or 1666.43 feet/min. That is 18.93 MPH. With the new transmission at 2100 RPM the tire would be turning 366.94 revs per min or 2078.95 feet/min. That is 23.95 MPH. I would like to point out that if you go this slow, you are a douchbag. In a civic. With 44" tall tires. But that is besides the point I suppose.

You don't mention the grade of the street you are on, but the steepest in the continental us is in Pittsburgh at 37% I believe. (there is one in HI that is steeper IIRC, but you can't drive a civic on it.) 37% is 37 feet vertical per hundred horizontal. At a 1/2 mile like you state, you would be 976 feet (297.48 M) higher at the end than the beginning. Your civic is 1045 KG. In a perfect world, that is 3049650.55j of energy. That is 728 Calories, or roughly what is in a double quarter pounder with cheese from mcdonalds.

Since you are driving at 18.93 MPH (1665 ft/min) on a 1/2 mile hill, you will cover the 2640 feet in 1.584 minutes. Your car needs to do 3049650.55j of work in 1.584 minutes. 1 HP is equal to 2,684,519.54 joule per hour or 44742.0j per minute. Since you have 1.584 minutes to do the 3049650.55j of energy, you need to do 1,925,284.44j per minute. That equates to you currently using 43.03 HP in 2nd gear at 2100 RPM.

Using your new transmission at 2100 RPM, you would cover 2107 feet per minute and cover the required distance in 1.25 minutes. That means you need to do 2,439,720.44j per minute. That is 54.52 HP.

I forget where I am going with this and I don't feel like doing any more math, but the summary is you have no clue what you are talking about.


I would pay to see you drive over a civic with 44" tall tires. You would need to be bigfoot.

:awe: Post of the year! :awe:

 

[BassBomb]

i feel spoiled that i manage 30-40MPG in a large car on my route

 

[jhu]

I have to agree with the general sentiment here: it's not worth it. Now if you could get a lean-burn engine in there too, then it might be worth it. But just a transmission alone isn't. But, as someone also mentioned, why not just ride your bike to the gym? That way you can get your cardio workout over with and just do weights.

 

[fleabag]

Post pictures of the transmission swap when you are done.

Is that better?

No. LOL I still don't understand... How are pics of the transmission swap before or after going to help considering that it's going to look exactly the same!? Why don't I just take a picture of the engine bay twice and just say I did the swap...

 

[sdifox]

The only good solution I can think of is to build a giant trebuchet. you just drive up to the loading area, get off your car, rack up the trebuchet, drive car onto launch platform, pick up trigger wire, sit in car and yank.

 

[fleabag]

First, I would never bother doing this.

Second, if you DID do it, I wouldn't see any problem since the VX you'd be pulling it from already makes LESS power than the LX you want to swap it into. So even with the taller gears you'd still be better off than the original car it came from, and Honda was okay building that car. I'll hedge a bit by noting that the VX was a fair bit lighter than the LX, but even so I think it would be fine.

Not quite true. The reason I say this is that while the LX has more peak HP and torque, the VX has not only lean burn but VTEC where 1 intake valve is kinda open at low RPM and 2 intake valves fully open at high rpm opposed to the LX where it always has 2 intake valves fully open. This feature alone not only gives much better response at low RPMS in the VX compared to the LX but you also get more complete combustion at those revs which means better mileage.

Post pictures of the transmission swap when you are done.

Is that better?

No. LOL I still don't understand... How are pics of the transmission swap before or after going to help considering that it's going to look exactly the same!? Why don't I just take a picture of the engine bay twice and just say I did the swap...

I have to agree with the general sentiment here: it's not worth it. Now if you could get a lean-burn engine in there too, then it might be worth it. But just a transmission alone isn't. But, as someone also mentioned, why not just ride your bike to the gym? That way you can get your cardio workout over with and just do weights.

Too far away to do that, not to mention the fact that I have to contend with the 1/2 mile long gradient just to get there.. There are just too many reasons for me not to ride a bicycle to the gym but if I could, I probably would. As for the lean burn engine, I most definitely want to do that, but that is going to require a huge amount of planning and the acquisition of parts, dealing with emissions, etc etc. The engine will have to be something that I do over a longer period of time with the transmission being something I do maybe over a weekend. Doing the transmission swap should be a cakewalk compared to doing the engine swap for the fact that the car doesn't even come with VTEC, let alone having to deal with stuff like adding an EGR system and whatnot. It's a big mess that I'm still trying to wrap my head around...

 

[Fenixgoon]

:awe: Post of the year! :awe:

that's gotta be worth of ownage of the year 2010 :awe::awe:

 

[jhu]

No. LOL I still don't understand... How are pics of the transmission swap before or after going to help considering that it's going to look exactly the same!? Why don't I just take a picture of the engine bay twice and just say I did the swap...

It seems like what he meant was for you to take a bunch of pictures of the car in various states of disassembly, something along the lines of

1) car with current transmission in it
2) "new" transmission by itself
3) various pictures of car jacked up with transmission/engine in various states of disassembly
4) car jacked up with visual of "new" transmission in place
5) pictures of old transmission by itself.

Too far away to do that, not to mention the fact that I have to contend with the 1/2 mile long gradient just to get there.. There are just too many reasons for me not to ride a bicycle to the gym but if I could, I probably would. As for the lean burn engine, I most definitely want to do that, but that is going to require a huge amount of planning and the acquisition of parts, dealing with emissions, etc etc. The engine will have to be something that I do over a longer period of time with the transmission being something I do maybe over a weekend. Doing the transmission swap should be a cakewalk compared to doing the engine swap for the fact that the car doesn't even come with VTEC, let alone having to deal with stuff like adding an EGR system and whatnot. It's a big mess that I'm still trying to wrap my head around...

Well, good luck with that. I'd rather just buy a another car. The first gen Insights are fairly cheap now.