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sarguy01 · 07-29-2014, 01:28 PM

Welcome!

There are several of us on here that have 7th Gen Civics. Mine is an 05 Sedan with a 5 speed.

As far as I know, the only engine that will bolt to a 7th gen transmission is a D17. I don't think a D15 will bolt to your transmission. But, you could always swap out the transmission too. Is this an auto or manual? If you have a manual and swap in older generation's manual, you will be going from a cable shifted to the rod shifted.

Then there is the ECU to reprogram and replace. A swap might end up costing more than the MPG increase is worth. I'd throw in a junkyard/Craigslist D17 (new timing belt, water pump, etc) and call it a day. If you have a manual transmission, you should be able to hit 40 MPG at a minimum. Up until it got blazing hot here and I started using the AC, I was able to keep a 40 MPG average in traffic.

But, if you wanted to do something different, grab an EX/HX motor and HX ECU (can 7th Gen Civic's ECU even be swapped? I am thinking out loud...) and throw it in your car. Then, you can have a lean burn sedan!

07-29-2014, 01:28 PM	#2 (permalink)
sarguy01 Master EcoModder Join Date: Jan 2010 Location: Virginia Beach Posts: 468 Mazda5 - '12 Mazda 5 90 day: 25.22 mpg (US) Big D - '11 Dodge Durango Crew 90 day: 18.75 mpg (US) Thanks: 86 Thanked 87 Times in 54 Posts	Welcome! There are several of us on here that have 7th Gen Civics. Mine is an 05 Sedan with a 5 speed. As far as I know, the only engine that will bolt to a 7th gen transmission is a D17. I don't think a D15 will bolt to your transmission. But, you could always swap out the transmission too. Is this an auto or manual? If you have a manual and swap in older generation's manual, you will be going from a cable shifted to the rod shifted. Then there is the ECU to reprogram and replace. A swap might end up costing more than the MPG increase is worth. I'd throw in a junkyard/Craigslist D17 (new timing belt, water pump, etc) and call it a day. If you have a manual transmission, you should be able to hit 40 MPG at a minimum. Up until it got blazing hot here and I started using the AC, I was able to keep a 40 MPG average in traffic. But, if you wanted to do something different, grab an EX/HX motor and HX ECU (can 7th Gen Civic's ECU even be swapped? I am thinking out loud...) and throw it in your car. Then, you can have a lean burn sedan!