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I have a 99 Honda civic Lx with a D16Y7 engine and auto tranny, I would like to switch to a D16Y8 engine with auto tranny, but I鈥檓 not sure what is compatible and what isn鈥檛! If I could get some recommendations on what to do that would be great 馃憤馃徑
 

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the search feature is a wonderful tool, you should give it a try.
 

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If you are VERY detailed oriented, organized, and dedicated to recording all necessary mods, you can strip the auto part of the harness out, do the conversion from 3 wire IACV to 2 wire, and re-use some of the auto wiring for the reverse switch, and also use auto wiring for the vtec conversion.

Then it is the matter of getting the correct ecu plugs, and the correct 1999 or 2000 EX manual ecu.

Good luck.

Unfortunately it makes more sense to find a manual EX nowadays. Parts simply are not nearly as cheap as they once were.

I remember being able to do B swaps for under a grand with many new parts even!
 

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If he is going from a '99-'00 Y7 Auto, to a '99-00 Y8 Auto, wouldn't he simply need the VTEC wire(s) (sub-harness' for this used to be around everywhere, but I haven't checked in a while)?
Primary and Secondary O2 sensor locations 'changed' on the chassis' across '96-00, and I don't recall what Trims/engines dictated this, but I would trace them on both Y7 and Y8 '99-00 harness', to be sure.

EDIT:
O.P. will obviously need a '99 Y8 Auto. ECU as well, hoping that is already known.
 

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99-00 Y7 engines had the secondary O2 sensor under the cat manifold. All he would need is an extension if he decides to run a Y8 style cat.

But the Y7 cat setup will bolt onto the Y8 of course, and save money. It doesnt hamper horsepower like magazines would want you to believe. I dont like giving up 10-15 torque in favor of 2-3 horses up top.
 

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99-00 Y7 engines had the secondary O2 sensor under the cat manifold. All he would need is an extension if he decides to run a Y8 style cat.

But the Y7 cat setup will bolt onto the Y8 of course, and save money. It doesnt hamper horsepower like magazines would want you to believe. I dont like giving up 10-15 torque in favor of 2-3 horses up top.
When I had a Y8 head on a Y7 block I used a Y8 style exhaust system and exhaust maifold/header.

I have a 99 Honda civic Lx with a D16Y7 engine and auto tranny, I would like to switch to a D16Y8 engine with auto tranny, but I鈥檓 not sure what is compatible and what isn鈥檛! If I could get some recommendations on what to do that would be great 馃憤馃徑
You will have to take the one wire from the VTEC solenoid plug that plugs into the solenoid and then run a long wire into the cabin and pin it into the ECU pinout for VTEC to work for one. You will also have to convert your IACV wiring because the Y7 and Y8 are different. One is 2 wire the other is 3 wire. Most of everything else should be a direct swap, you will need the 99-00 ECU and preferably the 99-00 long block.
 

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When I had a Y8 head on a Y7 block I used a Y8 style exhaust system and exhaust maifold/header.


You will have to take the one wire from the VTEC solenoid plug that plugs into the solenoid and then run a long wire into the cabin and pin it into the ECU pinout for VTEC to work for one. You will also have to convert your IACV wiring because the Y7 and Y8 are different. One is 2 wire the other is 3 wire. Most of everything else should be a direct swap, you will need the 99-00 ECU and preferably the 99-00 long block.
O.P. states this swap is Automatic - to - Automatic.
-So, IACV units, for the 'Y7 and Automatic 'Y8, are the same, nothing to do there.
-Also, VTEC Solenoid is not the only wire. Knock sensor will need to be run as well (use a shielded cable).
-Lastly, I thought there was an Oil pressure switch @ the head too, for VTEC activation, but this might only be B-series engine, can't remember.

To the O.P.: If you can get the complete engine harness, with the 'Y8 swap, you are ahead of the game. It will save you from having to run the VTEC wires.
 

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The transmission MUST also be swapped. the Y8 ecu with the built in TCU will want to know the correct shaft speeds from the different gear ratios.

The y7 tranny will put it into limp mode eventually
 

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O.P. states this swap is Automatic - to - Automatic.
-So, IACV units, for the 'Y7 and Automatic 'Y8, are the same, nothing to do there.
-Also, VTEC Solenoid is not the only wire. Knock sensor will need to be run as well (use a shielded cable).
-Lastly, I thought there was an Oil pressure switch @ the head too, for VTEC activation, but this might only be B-series engine, can't remember.

To the O.P.: If you can get the complete engine harness, with the 'Y8 swap, you are ahead of the game. It will save you from having to run the VTEC wires.
I stand corrected. I believe that you are correct. It has been roughly 3 years since I have done the conversion now and my memory may be foggy!
 
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