- Asking for a friend.

We have an Evo 9 Chassis and put in a built Evo 8 block/head into it and am wondering if there is anything we need to prepare to get it running? I've done searching and can only find threads on people bashing eachother for getting rid of mivec, so please keep that out of here.

Everything, the way I understand it, should relatively be the same except we'll have a disconnected intake cam sensor and we will probably have to leave the mivec table to all 0s.

Any advice is greatly appreciated.

 

You will have to find a evo 8 engine harness and evo 8 ecu. I have done this myself and it is easy. The harness starts at the 2nd o2 sensor under the passenger seat and ends at the fuse box at under hood by drivers strut tower. I did change mine with the engine in the car and it was no fun but can be done. Only difference is the 2nd o2 sensor plug so if you are using it you'll need to buy a evo 8 o2 sensor.

 

We would most likely wire in an AEM into a 5v input and use it for closed loop control, so thanks for the heads up on that!

So this absolutely cannot be done with the Evo 9 harness? We have the engine already dropped in and plugged up. It currently has a Haltech Evo 9 ECU in it but the car just does not run consistently.

 

I don't think it'll work for you whereas the evo 9 ecu is looking for both cam signals. I'm not good enough to tell you if you could go into the cam signal settings and ignition and change that stuff around or not. I was in the same boat as you and I ended up just swapping the harness which only took a couple hours and called it a day.

 

The car is idling on stock Evo 8 ignition timing now with Mivec set to zero in all tables. However during slow throttle inputs rpms will hunt. And during start up you must give it at least about 5% throttle and hold til o2 correction initiates before slowly letting throttle out to let idle. Which I want to blame all this being effected by intake mivec. It's been frustrating.

 

When I was doing this I called a couple "bigger" name guys about it and we all agreed the harness and ecu needed swapped to work. I am interested in what you end up doing.

Good luck

 

You do not need to change the wiring harness or ECU. When I converted to an EVO 8 cylinder head I simply removed all MIVEC and the intake cam sensor wiring from the harness.

You have to make a few changes in your EMS for it to work correctly. What exactly gets changed in the EMS I cannot recall. I'm sure it slightly varies based on what EMS you are using.

 

You can load the evo 8 base map from haltech. It is in their software. This will eliminate the ECU looking for the mivec inputs.

 

There ya go. I figured there's a way in programming but no one I spoke with knew how so I went the simple route imo. Thanks for the info guys.

 

I attempted this but when trying to upload a map it only allows a specific file format which doesn't include the Evo 8 files.. possible I overlooked something though. This would also change the input configuration and everything correct?

Thanks for the replies guys!

 

I would contact haltech to figure it out. The ecu's are universal. You should be able to put any file on it.

 

Any status update on this? I will be in the same boat come winter time, curious as to any problems or issues I might run into.

 

Im on evo9 chassis on Evo8 engine.
Run Aem V1.
Just disable the Mivec & get a tune.. It good to race.

 

sounds good fellas. thanks for the input

 

just ditch the mivec stuff. good idea aftermarket ecu better than trying to splice a 8 harness and ecu into it lol