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

[fleabag]

Do you use a car's lb-ft of torque numbers or just HP numbers? I have to ascend a hill to get into town and it's a pretty steep hill. I want to swap out my transmission for one with taller gearing (lower RPMs for a given speed) but I'm concerned that my current engine may not have enough power to ascend this hill in 2nd gear like it currently does after the transmission swap.

I was only able to find one dyno chart for a D16Y7 and it's of one with a modified intake and exhaust system.

Here are the gear ratios for a DX/LX transmission:
3.25
1.762
1.172
0.909
0.702
Final: 4.058

Here are the gear ratios for a CX/VX transmission:
3.25
1.761
1.066
0.853
0.702
Final: 3.25

So that would mean there would be a 20% less power available at a given speed in 2nd gear because of the gearing being taller with the VX transmission over the LX transmission.

We're done here. There's no more useful information being given in this thread.

Zenmervolt - AnandTech Moderator

 

[CurseTheSky]

While this doesn't answer your question, I have two thoughts:

First, unless you have this transmission sitting around or you're getting it dirt cheap ($50 or less), it would take a lot of driving for you to make back your money based on increased fuel economy from the taller gears. You'd be better off just pocketing the money.

Second, if you did the swap and found that your car didn't have the power to make the hill in 2nd anymore... couldn't you just drop it into first? Yeah the RPMs will be higher and you'll be burning up more gas, but one hill (even commonly driven) is a drop in the bucket compared to a several-mile trip every day.

 

[Sukhoi]

While this doesn't answer your question, I have two thoughts:

First, unless you have this transmission sitting around or you're getting it dirt cheap ($50 or less), it would take a lot of driving for you to make back your money based on increased fuel economy from the taller gears. You'd be better off just pocketing the money.

Second, if you did the swap and found that your car didn't have the power to make the hill in 2nd anymore... couldn't you just drop it into first? Yeah the RPMs will be higher and you'll be burning up more gas, but one hill (even commonly driven) is a drop in the bucket compared to a several-mile trip every day.

Remember this is fleabag. Do not take any posts seriously.

 

[RedArmy]

*If* you actually swap out transmissions, I want to see a video of you removing the bitch pin.

 

[fleabag]

While this doesn't answer your question, I have two thoughts:

First, unless you have this transmission sitting around or you're getting it dirt cheap ($50 or less), it would take a lot of driving for you to make back your money based on increased fuel economy from the taller gears. You'd be better off just pocketing the money.

Second, if you did the swap and found that your car didn't have the power to make the hill in 2nd anymore... couldn't you just drop it into first? Yeah the RPMs will be higher and you'll be burning up more gas, but one hill (even commonly driven) is a drop in the bucket compared to a several-mile trip every day.

I can get this transmission for no more than for $150 with $100 being the sweet spot. Such a transmission swap could easily pay for itself even if it was DOUBLE the cost... The gains from a successful swap would be very tangible. As for shifting into 1st gear, yeah I could do that but that's the difference between cruising at 2500rpm and screaming at 4000rpm as 1st gear on the VX is still too short for such a task. I guess what I'm going to do tomorrow is look at the scan gauge LOD (Load Indicator) and see what the load is when cruising up the hill in 2nd gear at the speed I want to go.

This probably wouldn't be such an issue if I just had the D16Y5 engine already installed...

 

[jlee]

Pics of swap.

 

[Zenmervolt]

In my experience, unless you are trying to tow a boat or something, pretty much any car can ascend pretty much any hill in second gear. Really, this is something that only someone with very limited (or nonexistent) driving experience would have to wonder about.

Not only that, but the differences in the power curves of the standard engines in the cars you list are so small as to be largely academic. The difference in power between the stock Civic VX engine and the stock Civic DX is simply not enough to be meaningful in everyday driving.

Also, didn't you used to claim to drive a Volvo?

ZV

 

[BlackTigers]

Here, this will be easier than your calculations.

Clutch in
Blip throttle
Move to first
Clutch out

That would fix the problem.

 

[StageLeft]

I presume you're doing this to save gas and because you know how that car's gear ratios should be better than the Honda engineers? That's a fair statement, Honda only started making cars last year and recruited beggars off the street for their development teams.

 

[fleabag]

Pics of swap.

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

I presume you're doing this to save gas and because you know how that car's gear ratios should be better than the Honda engineers? That's a fair statement, Honda only started making cars last year and recruited beggars off the street for their development teams.

You're the second person I've heard say such a stupid statement! First of all, the transmission I'm swapping it out with happens to be a transmission made by Honda. Secondly the DX/LX civic weren't designed for maximum fuel economy like the CX/VX were which I WHY I would swap in the CX/VX transmission for this. That same stupid logic could be applied to a person wanting to swap a DX/LX transmission into an EX Civic.

 

[fleabag]

*If* you actually swap out transmissions, I want to see a video of you removing the bitch pin.

Wat?

 

[BlackTigers]

Wat?

....lol. You should probably read up on tranny swaps before you think one up.


And, I thought you drove your mommy's volvo or whatever? WTF are you doing swapping transmissions in a Honda?

From quick research, consider about 5MPG increase.

Cost of trans ($100) You'll break things. Bolts, nuts, mounts....add in that to the swap. You'll need fluids. Grease. Etc, etcd.

Figure out how much that extra 5MPG will save you, and don't forget to count labor in as well, unless your time means nothing to you. And I'm going to suggest changing the clutch/resurfacing flywheel/replacing ToB and pressure plate while you have the transmission on the ground. Call this preventative maintenance.

You're looking at several hundred, plus labor, for a possible 5MPG with worse acceleration....

 

[yh125d]

Fleabag wants to do a tranny swap to get up a hill easier....




This is the pinnacle of idiocy folks

 

[mb]

Fleabag wants to do a tranny swap to get up a hill easier....




This is the pinnacle of idiocy folks

He doesn't actually have a car so he just likes to pretend.

In reality, all he has is a bicycle and has trouble peddling up hills.

 

[fleabag]

....lol. You should probably read up on tranny swaps before you think one up.


And, I thought you drove your mommy's volvo or whatever? WTF are you doing swapping transmissions in a Honda?

From quick research, consider about 5MPG increase.

Cost of trans ($100) You'll break things. Bolts, nuts, mounts....add in that to the swap. You'll need fluids. Grease. Etc, etcd.

Figure out how much that extra 5MPG will save you, and don't forget to count labor in as well, unless your time means nothing to you. And I'm going to suggest changing the clutch/resurfacing flywheel/replacing ToB and pressure plate while you have the transmission on the ground. Call this preventative maintenance.

You're looking at several hundred, plus labor, for a possible 5MPG with worse acceleration....

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).

 

[ayabe]

Just inflate to sidewall after doing the swap.

Here's the equation you need:

<2nd gear ratio>/<lb/ft@6000rpm> +<I don't have a fucking car>^<sidewall psi>

 

[fleabag]

Fleabag wants to do a tranny swap to get up a hill easier....




This is the pinnacle of idiocy folks

You fail at reading comprehension..

nice try....

 

[Vette73]

I'M POSTING IN A FLEABAG THREAD!!!


<waves>

 

[bruceb]

Second or third gear in a manual shift car, should do fine up any hill.
I know when I used to have an 1985 RX-7 that it would do that just
fine and make for a fun drive up the hill. And I am talking about Skyline
Drive thru Oakland and into Ringwood, NJ .. Up one side of the mountain, around and then down the other side. And it is like a 15 - 20% grade .. but a nice ride (just watch out for the cops)

 

[yh125d]

You fail at reading comprehension..

nice try....

I've never known someone with more air in their head

 

[coxmaster]

Too lazy to care about actually calculating or helping with anything. Im just curious about this one line.

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).

Since when is 2600 RPM "screaming"? Even on a 4cylinder that usually isnt loud at all

 

[fleabag]

I've never known someone with more air in their head

You're in no position to be saying who is the airhead. The thread is about swapping transmissions with the former having shorter gearing, therefore a better chance of climbing a hill vs. the latter transmission having taller gearing and therefore a worse chance of climbing a hill. The transmission that comes with the car can't climb the hill in 3rd gear (maybe it can if I have it revved to its peak torque) but CAN do it fairly easily in 2nd gear. Yes I'm aware I can ascend the hill in 1st gear, but the better question is, if I put in this "new" transmission, will I still be able to ascend the hill in 2nd gear?

I don't know, but I'm going to try and find out by doing some calculations and get some insight by someone with something more than snarky comments.

Too lazy to care about actually calculating or helping with anything. Im just curious about this one line.



Since when is 2600 RPM "screaming"? Even on a 4cylinder that usually isnt loud at all

Everything is relative, some people consider 20mpg "good" I consider it "awful" some consider 40mpg "amazing" I consider it "ok"... It isn't THAT loud but it's definitely unnecessarily loud especially considering that all I'm doing is cruising.. Also I happen to have an exhaust system on this car (came with it) so it tends to amplify certain RPM ranges.. Anyway a hell of a lot more air is being sucked into the engine and consequently being burned at 2600rpm than at 2100rpm. If I want to accelerate, I could always shift into 4th gear and that would still have a lower rev (about 100rpm less) than when I'm in 5th gear.

To give you an idea of how I drive in the city, I typically go 1st->2nd->4th(20mph)->5th(25mph). The annoying part about city driving is that I find myself needing to shift while in the middle of the intersection.

 

[Sid59]

Second or third gear in a manual shift car, should do fine up any hill.
I know when I used to have an 1985 RX-7 that it would do that just
fine and make for a fun drive up the hill. And I am talking about Skyline
Drive thru Oakland and into Ringwood, NJ .. Up one side of the mountain, around and then down the other side. And it is like a 15 - 20% grade .. but a nice ride (just watch out for the cops)

Haha, i work at the top of Skyline and Redwood. I always forget to look but what's the grade on the Redwood vs Skyline slopes? Since I drive the hill between 5-10 times a week, have you figured how much it kills MPG?

 

[coxmaster]

Everything is relative, some people consider 20mpg "good" I consider it "awful" some consider 40mpg "amazing" I consider it "ok"... It isn't THAT loud but it's definitely unnecessarily loud especially considering that all I'm doing is cruising.. Also I happen to have an exhaust system on this car (came with it) so it tends to amplify certain RPM ranges.. Anyway a hell of a lot more air is being sucked into the engine and consequently being burned at 2600rpm than at 2100rpm. If I want to accelerate, I could always shift into 4th gear and that would still have a lower rev (about 100rpm less) than when I'm in 5th gear.

To give you an idea of how I drive in the city, I typically go 1st->2nd->4th(20mph)->5th(25mph). The annoying part about city driving is that I find myself needing to shift while in the middle of the intersection.

I see. Fair enough point.

Also, my automatic transmission shifts just like that (assuming I punch it). Anything over 35ish and its in 5th gear. 40+ and its probably in 6th by then.

Also, all cars have an exhaust system, its sorta required by law.

 

[Demon-Xanth]

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?