Anyone had this happen with their factory Evo IX intake manifold? Just found this today. What would cause this? Wanted to see if this is common or just my bad luck.

 

That looks to just be some sort of casting flash in between the runners and isnt actually a hole inside the intake manifold.

 

I was wondering if it was or not, because I sprayed some soap/water mix around doing a boost leak test and didn't get any bubbles but I'm getting a clear steady slow hissing sound right in that area. Checked all the lines and no bubbles so far. Search continues.

 

The soapy water trick works excellent for getting a visual on the pesky boost leaks that you can hear but cant exactly pinpoint or feel with your hand. If take a look at the injector seals as that could be your culprit in that area. Also the throttle body shaft seals like to leak and even the o ring for the biss. But if its in that area I'd target the injectors.

 

Think I just found the culprit, throttle body shaft seals, because when I move the throttle, the hissing sound changes as I'm moving it. What's the biss?

 

The biss is the screw in the throttle body that lets you adjust the idle, you can spray some soapy water into the hole around it and if it bubbles up your biss o-ring is shot. If your doing the shaft seals it's an ideal time to to replace the biss o-ring. If you do need to replace the O-ring count how many turns it takes to fully tighten the biss so you can get it back into a similar position after you are done. Otherwise you will need to search for the procedure to adjust the biss correctly.

 

that manifold is fine... just cast flashing.

 

As mentioned the biss is what sets your idle, think it stands for base idle set screw, bc well it does exactly that. If you dont have a means to turn off your IAC with evoscan and a tactrix cable be sure to keep tabs on how many turns it was set to so youd idle doesnt change when going back together.

Also, you mentioned that you heard a hissing sound as you played with the throttle blade.As you open and close it the tone could change as when closed its trying to block all the air from entering the IM and once open well it rushes in. My point is just bc you are hearing noise from there doesnt mean your shaft seals are bad. The way to tell if they are leaking is is any air is leaking externally so feel on the sides or spray soapy water and see if its bubbling. They are very prone to leaking so wouldn't be surprised if they are but confirm its an external leak first.

 

I bought a cheap smoke-making test tool to do this kind of thing. It works wonders because you can see smoke leaking out of leaks. It was only 150$

 

Too much NOS will blow the welds on your intake manifold.

 

Are you able to add positive pressure with that as well? Smoke machines seems to work great for spotting leaks in things like EVAP. While you may find some leaks in the charge pipes with just the smoke if you aren't pressurizing it to at the very least how much boost you plan to run you could actually have leaks that haven't made themselves apparent. I say this because when I perform a boost leak test there will be couplers that aren't leaking at 10# but at 20# they are. Had I not had positive pressure I would have never known.
Lol spoken like a true champion

 

The regulator on the smoke machine must not be any higher than 1 or 2 PSI I would guess. It is very low. I have not measured. In my past, I have had issues on the evo with the very small coupler hoses coming loose from my EGR- it will help you spot that right away. I use an "inflatable bladder" style adapter that i shove in the intake after I remove the MAF. I do not see why you could not fill the VOLUME of the intake with smoke, and then hook up a conventional "boost leak" tester and test at your 20 or 30 psi. When I do mine, I fill it for about 2 or 3 minutes until I see a steady stream leaking from the little weep hole on my boost level adjuster. Mine runs on mineral oil, which is cheap and available publicly at your typical walmart or other stores.