I'm guessing that oil was being sucked up from the PCV.

 

Sorry Rafi, forgot to mention I pulled the negative as it heat soaked. Values were at 15 and did some pulls

 

I highly doubt Seafoam will do anything to clean that much buildup out. You're looking at a walnut shell blast to get that much carbon buildup out. I thought the port fuel injectors were suppose to prevent this type of buildup? I wonder how common this problem is with our ISF's?

 

Maybe cars that are KCLV challenged have a bunch of carbon build up to this level and therefore the compression changes and the knock sensors pull timing because of this?? Just a thought, but like FFM said above this looks like the carbon build up of an Audi DI engine

Anyway to scope the engine to see this buildup without taking it apart to see this?

 

You all would be amazed at what a good shot of water would do to that carbon. That build up is tiny compared to any number of engines I have seen.

No, it's not oil from PCV. It's backwash from cam timing induced EGR. Normally our port injectors will clean this off pretty handily which is why you don't hear about carbon build up on 2GR and 2UR engines, but the 4GR in the IS250 is plagued by it.

 

I know I'm a little late to this thread, but I thought I'd chime in anyway lol. On my C30 Rotrex Supercharged Si, the guys at sea level were making 10-11 psi and I was making anywhere between 5.0-6.5 psi on a cold day. Plus, our density altitude changes daily, so it will depend on that as well. I'm sure the C38 Rotrex is similar to the C30 (efficiency and design), so at this altitude (5,500 feet), I'd expect to run about 50% of the boost levels this kit makes at sea level. My biggest issue though, was knocking once the temperature got above 95 degrees F, at partial throttle in 6th gear, due to the lack of oxygen up here. I'm hoping this SC kit doesn't have those issues at our high altitude.

 

Can you explain how you would use the water? Like the seafoam method?

Thanks

 

I connect a liter bottle of water with a hose to the port where the airbox flap gets its vacuum. The hose goes to the bottom of the bottle. I pinch the hose shut, start the engine (you need to be sure it is at full operating temperature - this should be a restart, not the first start of the day), and let the hose open with the rpm at 2000 - 2500. Let it suck the bottle dry, and refill if you like. You'll likely see clouds of steam coming out the exhaust, but you'll also be decarboning the whole system - valves, ports, pistons and heads. It's the best thing to do right before a teardown if you can because it will make cleaning pistons, heads, and valves a whole lot easier. It is truly best if the engine is really fully hot. The water atomizes as soon as it leaves the port in the manifold.

With carbureted engines, I would just pour water in a quart at a time. It's almost impossible to pour too fast, so the whole worry about hydrolocking is way overstated.

 

Thanks so much for the response! So this here (where its capped off), or where the tube is being held? Im trying to figure where it will be in engine side of the air filter..

 

Not there. Here where the red arrow is:

 

Ahhhhhh i see, thanks so much, most appreciated! I have a job now on this rainy day.. Strangely excited to try this.

 

Well.. That was a wee bit stressful.. My colleague "helped" me by holding the RPM steady, strict instructions: "hold it at about 1800-200rpm". Hes not a car guy, mistake.

I couldnt hear him, and i was yelling "what are the revs at?" and couldn't hear his reply. Turns out he was saying "im flooring it!! Only goes to 3,000rpm!!"

Car was in semi limp mode haha, and he is flooring it?! Anyway, long story short, after letting it run for a 15 seconds after the water was empty, turned off, turned on, good to go few big revs steam out exhaust etc. Few long pulls in second and third, then took it for a belt, lighting the tyres on slightly damp roads at 80kph in second. Probably placebo, but dont really think its ever done that before, hopefully the KCLV is in better shape now.

Will hold onto the bottle setup now for a repeat procedure down the track, just periodically moving forward.

 

so u place the tube in the water and let it suck it up?

 

Sort of. I let atmospheric air pressure push the water into the manifold.

 

I agree that the carbon build up in that port is not as bad as everyone is suggesting. I have also seen far worse in DI engines. Take a look at an N54 and your prospective will be changed. I also think this is partly influenced by how and when the car is driven.
I removed an intake manifold and valve covers to do an inspection on a 140k motor and it was very clean considering. The intake manifold was extremely clean and I was able to wipe down most of the carbon in the ports with a damp towel.
Mind You this particular ISF gets driven often and hard. It also is not equip with any type of oil separator.
I can also note that the valve lash inspection results were optimal with no adjustment needed.