Manual transmission – is this normal?

[Chris]

So I have a 97 civic HX and wanted to have an answer to a question that has been bugging me. Before I ask it however I want to give you insight on what I have done to this car so far. I got this car as a salvage. It ran horribly and lost a quart or more of oil every 20 miles or so of driving. It shifted really high up on the clutch and would catch late (later found out it was a lot of oil that contributed to this now it is not so bad). The car needed tough love and care. I replaced most of the gaskets including the vtec solenoid gasket. The only ones I didn’t get to do were the head gasket (doesn’t really need it) and the water pump gasket (to be done soon along with timing belt) The engine doesn’t leak oil and I even have full synthetic oil in there so I know I did well with my repairs. I have also taken the EGR passages opened and cleaned those out. I got the car and wanted to fix it up because of its gas mileage. This car is supposed to get 36 city and 44 highway. I noticed that when I drive it though, on fifth gear it is getting up to 2500 rpm going 60 mph. when I get to 80, it has the rpm at 3200. Is this normal? in my 4 speed 93 civic automatic, it goes up to 2500 rpm going 80 mph and it has lower ratings for gas mileage. My guess is I need a new clutch? or is it something else? thanks for your help I really appreciate it.

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[college man]

3200 rpm at 80 is where you should be. thats not bad for that year of a car.

[Chris]

[quote=”college man” post=165917]3200 rpm at 80 is where you should be. thats not bad for that year of a car.[/quote]
Great thanks. Yea I’m surprised at the condition of it as well. I was just curious because my automatic 93 civic has lower RPM at that speed and it only has 4 gears. Guess its another lawsuit for Honda on their gas mileage haha :silly:

[David]

the engine speed at a given car speed is determined by the gearing in the transmission and differential, along with the effective tire radius – so you can calculate what it should be. Automatics, particularly those with fewer gears, tend to have a taller gear as the final gear (overdrive).

Here’s a website where you can do the calculations
https://wahiduddin.net/calc/calc_speed_rpm.htm

For your car, the gear ratio in 5th is 0.702 and the final drive is either 4.058 for the hatch or 4.250 for the sedan/coupe

For your old car, there are two different automatic transmissions, but in both 4th gear is taller than 5th in your automatic – 0.673 and 0.638, both with a final drive of 4.333

[Chris]

[quote=”DrD” post=165999]the engine speed at a given car speed is determined by the gearing in the transmission and differential, along with the effective tire radius – so you can calculate what it should be. Automatics, particularly those with fewer gears, tend to have a taller gear as the final gear (overdrive).

Here’s a website where you can do the calculations
https://wahiduddin.net/calc/calc_speed_rpm.htm

For your car, the gear ratio in 5th is 0.702 and the final drive is either 4.058 for the hatch or 4.250 for the sedan/coupe

For your old car, there are two different automatic transmissions, but in both 4th gear is taller than 5th in your automatic – 0.673 and 0.638, both with a final drive of 4.333[/quote]
That is great information right there thank you so much! That helps will all vehicles from here on out!

[Frank Heiser]

The other guys already answered but I can also confirm it’s normal. I have a Kia Rio automatic and my cousin has the same but with a manual, my automatic gets ~2500rpm at 70 and his manual runs ~3500rpm at 70.

[Chris]

[quote=”Nodak81″ post=166603]The other guys already answered but I can also confirm it’s normal. I have a Kia Rio automatic and my cousin has the same but with a manual, my automatic gets ~2500rpm at 70 and his manual runs ~3500rpm at 70.[/quote]
Yea I figured as much after looking a lot of different cars and comparing them to their automatic versions. Now the only question is how does a manual save more gas than automatics when the rpms go so high? Could it be that it requires less torque and less requirements to burn gas? Or am I wrong? Any logic on this would be apreciated

[Author]

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