I have my stock IM off and getting ready to put on the ported one when I noticed the tube at the mouth for the crankcase ventilation is missing.

Is this normally eliminated in the process of porting?

Is it expected that I'm supposed to remove the one from my stock manifold to insert in the ported one? And if so, how is that done?

Doing this stuff on a Sunday when every shop is closed was probably not a good idea. But I'm hoping for a little help from my forum friends.

 

In all my intakes that tube is cast as part of the intake. Of course mine are all ls2 models (factory and FAST). Perhaps the ls3 is different - can you remove your stock one?

I hope your isn't broken off in shipping. Even if so, you can fab something up from the parts store using fittings.

Aren't your parts stores open 7 days? Ours are open until 9 (which comes in handy indeed).

 

can you post a pic of the same location and point of reference of each manifold

 

Tom, it's ok to remove it. When I had my 08', I bought a ported IM from Formatto. The tube was removed and it never was a problem. When I say removed, I mean it was ground down flush with the side of the mouth of the intake opening.

 

Thanks Mark. That's exactly how my ported one is now and also the pics on the peakspeedshop posting.

My initial concern was when measuring the diameters, it appeared that it was possible to remove the tube from the stock IM and install it on the ported IM.

The OD of the stock tube is .390 in pic 1 and also in pic 3
The ID of the stock tube is .235 in pics 1 and 3
But the ID of the hole in the inside of the ported IM is .290 in pic 2, which doesn't quite fit the expected .077 wall thickness.

My assumption is that the tube extended toward the center of the plenum to provide a suction by creating a low pressure area during the high airflow of WOT. Seeing that the tube is located lower than the opening centerline, it would also create the suction even at a lower than WOT blade angle.

Without the tube in the airstream, it will still work OK under light engine loads (high vacuum), but will not provide enough, if any, crankcase scavenging at WOT when it's needed most.

I've had no catch can on this engine for 24K miles and only have a light film of oil in the IM. No puddles at all like I've seen pics of on LS2 motors. However, considering that the tube is missing and the likelyhood of more oil being in the airstream because of crankcase pressures, I will now be using a catch can.

Maybe I'm being a little ****, or maybe just trying to learn more. I know what my oil useage has been, so if it increases a lot and I'm trapping it in the can, then I'll make up a replacement tube to fix the problem.

Stock IM


ported IM


outer connection on IM

 

I thought you meant the outer connection.

The ls2 doesn't have that inner pipe.

 

Thanks for the pictures. Can you post up SOTP impressions and/or dyno numbers once you get everything all buttoned up? A ported IM is one of the last things I can do to my car while keeping it cam-only so I'd love some feed back if you don't mind.

 

I started to write a whole thing about SOTP and dynos, but decided it would just waste time.

Here's what I will do for ya. I ran a week ago and had a best of 11.08 in about 800' DA. I'm planning on running all three days of the Hangover Nationals (Dec 30-31 & Jan 1), so I'll report those times. Other than the ported IM, I'll also be on new tires, have the rollbar installed, and maybe have the racing seat in. I don't think the tires will make any difference and the weight will cancel itself, so any change will be the IM.

 

Good enough, thank you

 

My 08' didn't use oil before or after the intake install. YMMV.

 

I kinda guessed that.

In Phoenix, there are several parts stores open 24/7, but most are only open from before I get out of bed until 9PM.

Not having the inner pipe may be the reason catch cans are needed.

 

Glad to hear that. I'm putting a can on anyway, mostly because I have one, but just to check how much, if any gets trapped.

 

I put a catch can on my '08 about 3 or 4 months ago. It has yet to trap any measurable amount of oil. I know it has a mesh screen inside, so perhaps that's why nothing drains out when I release the valve, but I thought for sure I'd see something. As of yet, not a single drop has come out

 

You may be on to something there. I get a lot of oil in my catch can and before I had it, whew was my intake an oily mess.

Perhaps that tube is there for a reason!!

 

Lol, my FAST intake was SSOOOAAKKKEEDDDD in oil when it was pulled off for the blower. It could be poured out, easily.

You're lucky

 

Ya, when Tracy @ RX performance did the throttle body install, he showed me how coated the inside of the IM was, so I bought a catch can(sucker?), but it has yet to show any oil in it. I've had it on the car for about 3 or 4 months now but not a drop has come out.