After reading it I realized how little I knew.

 

Take your time and enjoy the car and the modificatin process. The evo is one of the sweetest cars you'll ever come across, congrats on getting one

 

thanks for all the info! it helped i actually bought an evo 9 bov for my evo 8 the swap should be pretty straight forward right? anything i should look out for?

 

Swapping the BOV is very easy. Just be sure to install it in the correct direction.

 

great thread with lots of information. helps alot

 

Solid information with a lot of explanation! This helps out tremendously for someone like me who is not mechanically inclined. Learned very little due to the specifics on how complex this vehicle is or maybe I'm just thinking too much. Either way thank you for this thread!!!

 

Wow great info here! Thank you heaps TS!!

 

some good information. realize that ive got so much more to learn

 

Very informative, if anyone has a evo 9 mr build that has just over 400 whp could I get your build list?

 

Couple quick questions:

"Evos do not respond well to BOVs."

^ Why is this and when would one get one for his Evo?

And the ACD fitment on the downpipes.

I been looking up downpipes for my car and none of them say if they'll fit with the ACD or not.

 

For the DownPipe just make sure its specific for the Model of your Evo. I as well have an 06 Evo IX not MR and with ACD. If you have any questions or concerns with fitment the easiest way is to just contact the shop your buying from be it online or local and just ask.

 

Oh and great Sticky by the way, very informative and pretty much broke it down Barney style with proper additional info if needed. Thank you very much for this

 

03-04 share the same downpipe
05-06 share the same downpipe

It does not matter if you have a Regular, an RS, or a MR.

 

THANK YOU!

That's what I needed to hear. That should be edited into this thread.

 

Not an expert on this subject, but briefly:

• Installing an aftermarket BOV will not increase power or improve spool, unless the OEM BPV is actually leaking
  
• Changing out your OEM BPV will almost always hurt driveability (i.e., smoothness of power delivery under part-throttle conditions). This is a pretty significant drawback (unless your car is purely a drag car)—it will make the car drive poorly when you're trying to use some but not all of your car's power during daily driving, track (road course) driving, and autocross
  
• No need to change out the OEM metal-bodied BPV until you're running more boost than the sealing capability of the OEM valve, which IIRC is around 25 psi, don't quote me on this though

If you just want your Evo to make loud sneezing noises when you get off the throttle, you can get about 75% of the audible discharge volume of an aftermarket BOV without the driveability downsides by installing an aftermarket intake system that gets rid of the factory air filter box.