Manual transmission change

I have a 2004 Honda CRV EX. It has 5 speed manual transmission. Any way to convert it to 6 speed manual transmission?

(I purchased a Acura TLS and the 6 speed manual makes the RPM low and mileage high. CRV has OK mileage but high RPMs so the engine may wear faster).

Nope, don’t worry about it, the 5th gear on the CRV is optimized for rpms/mileage. Very little to be gained, huge $$ to spend.

Your gas mileage is already about as good as you can get in a small SUV (the CRV is basically a glorified Civic). The newer CRVs have a 6 speed avalible, and it may bolt up to your engine, but you would spend thousands on it and probably not gain much in the way of fuel economy. Many small cars with small engines are purposely geared high because the small engines have very little low-RPM power. But I wouldn’t worry about it. Many Hondas and Toyotas have been built this way and they are considered reliable and long-lived cars.

The number of gears isn’t as important as the final gear ratio of the final gears. I’ll bet the ratio is pretty close.

I would suggest starting by taking a look at the final effective gear, taking into account tyre size as well.

In the end, I am going to guess the net difference is slight. You may gain or may loose a little mileage, but either is not going to make you a rich man.

Your driving style, the terrain you are driving in, the weather and length of drives etc all make a difference and the difference in those two transmission is not likely to be much.

With a six speed you may be able to match the engine to the power requirements better, but then you will also be loosing a little by the extra shift. 

An engine running faster is not always an engine using more fuel or wearing faster.  The slower running engine may be lugging shortening its life and reducing mileage. 

My guess is the switch will cost many times more than any potential fuel savings.

I did a little reasearch and here’s what I found out. For the newer 6 speeds the ratios are

1st: 2.786, 2nd: 1.614, 3rd: 1.082, 4th: 0.773, 5th: 0.566 Reverse: 2.000, Final Drive: 4.500

For the old 5 speed they are

1st: 3.533, 2nd 1.880 3rd: 1.212, 4th: 0.921, 5th: 0.7380 ,Reverse: 3.583, Final Drive: 4.765

So in top gear the with the 5 speed the overal ratio is 3.516 and with the 6 speed it’s 2.547.

The stock size tire for the 2004 is P205/70/R15 The stock size tire with the new model is P225/65/R17 . The new model’s tire have an overal diameter that is about 2.22 inch larger than the old model. I’m pretty sure that figures into the equation somehow as well.

Edit: Oops those figures for the “6 speed” are actually the ratios from the 5 speed automatic. It turns out the there was no U.S spec model offered with a manual transmission after 2006. The 6 speed manual was introduced in 2007 for other markets.

They all look the same after they have gone through a shredder. And that’s where they all go eventually. The “Powertrain” in todays cars is an integral unit, trying to re-engineer it in your back yard is loves labor lost…

Even if you could buy a 6-speed that will work…it better give you a 30% increase in gas mileage in order to make up the cost of that puppy. At BEST you’ll see a 1-2% increase.