okay to start off the two issues are unrelated i just figured id kill two birds with one stone since the catch can question might be a fairly simple answer.

first off i just want to make sure the previous owner routed the catch can properly, its just two hoses however ive seen so many different setups its hard to tell if its correct or not, also to add occasionally i can hear a faint bubbling sound a very tiny amount of smoke will come from the breather/filter when the car is started. im guessing its just the oil being hot but is that normal?




lastly im having an issue with overboosting, the car has basically all the typical boltons on a stock evo 8 turbo with comp 280 cams (kiggly springs and retainers) and a tune which the previous owner had done at whalen speed in Michigan if anyone is familiar with them. im guessing the tune would be set around 25-26psi but when i build boost and go wot the car will bounce at around 29-30psi and fall. the clutch seems to grab well, so im leaning towards a boost leak, i just tightened intake/intercooler hoses and clamps so ill probably have to do a little more searching
any input is appreciated!

 

Catch can setup looks ok. There's lots of debate over the proper way to route the system, but plenty of us just run 2 lines straight from the valve cover to a breather can. Some people like to have the vacuum ran back to the intake to provide negative pressure (something to pull air thru the system) but I've not seen any definitive evidence that there are any real advantages one way or another. The real answer to the question lies in what you are removing from the can? Some setups drain a half liter per oil change interval and others barely get a film inside the can.

I'll guess that this car is new to you. It's cold where you are. Boost tends to spike higher in cold weather. I can see your grimmspeed which would suggest an ecu controlled boost setup, which in theory "should" stabilize weather related boost fluctuations. But, having the same controller (as many on here do as well) I can tell you that's not the case. More advanced tuners (i.e. those who eat, sleep and **** evos) have solutions for such issues if you are so inclined to retune...which I greatly suggest since (I am guessing) the car is new to you. There are a handful of them floating around, and you don't need to be local to them either. Browse thru the dyno results section and you'll see who the front runners are.

I don't want to imply that tuning will fix any and all problems you may have (which based on your descriptions, the car seems ok in the areas of question). But again, I'm assuming the car is new to you...so you bought a previously modified car...nothing wrong with that as long as you are willing to take responsibility for your new property. Learn your platform (or pay someone who knows it specifically ), get it buttoned up where the previous owner likely left loose ends, and get the car tuned for the set of conditions you intend to operate it under.

I digressed a bit...a little smoke from catch can is normal (does not occur with mine but have heard of such cases where no ill cause or effect was noted). Boost leak sounds unlikely since you are achieving higher than target boost, but boost leak testing on our cars is an absolute requirement in any suspected boost related issue.

 

thanks! glad to clarify some of this and im not new to working on cars at all however the evos 4g63 is new to me. i know theyre reliable cars but given it has 130k i want to make sure its solid. it will be only driven in summer so the miles wont climb high that quickly once everythings been taken care of.. as far as the catch can i havent drained it yet, the temps have been in the negatives since i got the car but i will try to drain it soon and take a look. my guess would be theres only a small amount causing the bubbling/smoking.

I would like to run the setup for a month or two in summer but i plan on taking it down to either boostin in IL or finding a reputable forum member nearby who might want to help me over look things. its kind of hard to tell the A/F ratios with the cams but if i start the car and let it run without touching the gas it sits around 11.6

ill try to pick up a boost leak tester asap. from what you say i might not need it but its nice to have the piece of mind.

thanks for all the advice! just want to get the car in tip top shape the correct way

 

also one quick question since you seem pretty knowledable,
i have torque solutions rear diff mounts and the car is pretty loud at highway speeds. 1st and 2nd have a small wurring sound but 3rd and up it sounds like i can hear the diff spinning and its just about as loud as the exhaust, no grinds just the sound of gears turning. i know the cars absorbing the vibrations and im okay with the sound as long as its normal, i just wanted to double check since alot of others describe the sound as a wurr through all gears. ive had solid mounts on other cars as well but none awd so its a little new to me

 

The longest line that connects to the catch can should have a check valve on it. This is to prevent the catch can from being pressurized. I have blown up a catch can by not having a check valve to stop the boost from entering the can because the PCV on the valve cover failed.

 

Wow ive heard of that happening but I didn't realizethat it was how commonly that can happen, I will have to get one on there ASAP.

 

I have oem rear end mounts so I can't offer a comparison for what noises the solids might cause. The wurr sound in 1st and 2nd is pretty much universal in this car and you hear it regardless of how heavy or light throttle input might be. I can hear faint gear noises in 3rd just cruising, and if I slam it in 3rd or 4th I get a similar wurr noise. Warning sounds of diff failure are usually pretty obvious. Usually manifests as a louder whine that will increase in pitch with rpm regardless of throttle input. I say just drive the basterd and any weak points will reveal themselves. The car tends to not be too mysterious when it comes to real problems. You'll hear a different noise for every day of the week but a true issue will set off red flags if you have general performance auto knowledge.


This is only true if the can is routed like the oem pcv system. The oem system runs from the rear of the valve cover to the intake manifold and therefore must have a one way check valve so the crank case won't become pressurized by the intake manifold when you make boost. His configuration appears to simply run from the valve cover to the vented can. Just hope that whoever set it up plugged the intake manifold properly where the oem pcv line originally connected. Check valve is only necessary if the intake manifold is included in the loop

 

i cant say thanks enough for all this info, the search feature on this forum isnt the best haha. would it be a good idea to run a pcv inline just in case? and would you happen to have a picture of where on the intake manifold should be plugged? otherwise would running a t-fitting and pcv to the manifold and catch can be a better idea? im going to take a look at it tonight to double check.

thanks again! i cant wait to start driving the car as soon spring decides to come and wash away the salt and negative temps haha.

 

On the stock setup there is a line that runs from the intake manifold to the pcv valve on the valve cover.

The PCV valve looks like this:
http://www.streettunedmotorsports.co..._pcv_valve.htm

Should be threaded onto the back port of the valve cover. If its gone then make sure to get something to plug the open nozzle on the intake manifold.

 

well i finally got around to looking around the car and the good news is theres a pcv and i couldnt find anywhere that didnt have a hose or wasnt capped off.

i also got to looking in the catch can and it was just about full, is that normal?

 

There isn't really a "normal" amount since you don't know how long its been since the can has been drained. Empty it and check the level at regular intervals so you have your own baseline reference

 

alright just wanted to check, i guess ill be doing an oil change pretty soon then.

random but i noticed i cant find my maf sensor anywhere, ive seen some evo intakes dont have a mount for it like mine. where exactly does that get rerouted to and in your opinion are there upsides and downsides to not having it on the intake?
sorry again i tried to search and found a little info on an sti site for speed density vs maf and at least in the sti's case and most other cases its sounds as if tuning by speed density is much more accurate, im guessing that holds true to the evo platform too?