AndrewC

Sounds to me like you are talking about different things here:

Vulnax is correct about the connections at the inlet pipe end, but you don't want to block the PCV valve under the manifold.

IIRC the breather off the crankcase goes to a T-Piece, 1 leg goes to the PCV valve which you want to keep and 1 goes back to the inlet pipe, it is this connection that you want to pipe to your catch can.

Good thread here: http://bbs.scoobynet.co.uk/showthread.php?t=138077

Andrew...

911

Thanks Andrew. Spookyly just found the thread in Drivetrain!

My Sti v3 has a plastic connector mounted in the crank case.
One tube goes to the manifold valve, and the other to the inlet pipe, AND the rockers come to the plastic connector also.

Now, just which one goes to the catch tank, and i presume I simply allow the catch tank to vent to atmosphere.

Do I leave the plastic connector to manifold in place, seems I do.
Take the pipe to inlet tube (the one from the MAF), blank it off (so sealing that pipe off) and take that connection to the tank instead?

Hope that is right!

Graham.

StickyMicky

911 is your samco for your MY?

as my mates 97 uk car has a smaller MAF then mine and yours
maybe the samco is made for a uk car?

i have a red samco inlet for mine flying through the post as we type, should be here on monday, will report back how it fits, though mine is second hand and was listed as a stiv4 version

911

The pipe came from Roger Clarke and was specifically for the Sti v3, checked and tripple checked. cost a LOT of money.
Not impressed, and general fit under the inlet manifold was not too good.
What do you do though?
Brute force and vasaline got me just about there, but it was not a correct fit.


Graham.

AndrewC

Graham,

Funny that Andy brought that thread BTT just after I had posted a link to it

All you want to do is replace the 2 pipes (1 from crankcase, 1 from rocker covers)which did go back to the inlet to your catch can and blockup the holes in the inlet pipe.

My Catch Can is VTA via a K&N breather: http://bbs.22b.com/cgi-bin/ultimateb...=000038#000000

Pipe on left goes to T on crankcase breather, pipe on right goes to T on the metal breather pipe under manifold:


Andrew...

Andy.F

I thought I had lost that thread Andrew I needed some info from it for my website

Andy

911

Thanks to all, getting the tube this after noon.

More weekend fun

Graham

911

Finally some more progress.
Getting lightweight tube in the Industrial West Midlands is impossible, must all be in China!
Eventually found the tube and the Tee fittings in my local Aquatic Center....sad but true:

So starts the engine breathing mod to rid the inlet of the oil once and for all.

The 'kit':


And the circuit, admittedly sketched after I'd made it all, bit non techie that:


Getting the pipe onto the engine block connection was dangerous to the nuckles, but boiling water softened things a bit.
This is what I did in sequence:

1 Leave the subaru pipe from the engine block to the inlet manifold valve in place.
Remove the pipe from the engine block connector to the inlet pipe (my Samco one) and block-off the inlet pipe port.
2 Lead the flex pipe from the engine block connector to the fuel filter area. Cut it there.
3 Take the pipe off the metal tube which links the rocker vents in the 't' piece under the manifold. If your A/C is still there...hard luck! Plug that rubber pipe too that leads behind the alternator to the inlet.
Run a length of flex pipe from the metal tube 't' and route it round over the injectors and across to the previous flex pipe.
4 Tee the two flex pipes together. Lead the final flex pipe off the spare leg of the Tee to the catch tank 'inlet'
See following pics:


This is the engine block connector, bloody hard to photograph!


This is the flex pipe from the engine to the area by the fuel filter, the site of the catch tank. I have the Tee fitted here.


This is the detail of the rocker vent tube that joins each side of the engine to a Tee. You remove the stock pipe (and blank it off) and push a flex pipe into the exposed metal tee. Lead the tube round and over the injectors to meet with the Tee in the previous pic like so:



Finally, the tank, which is a push bike drinking bottle, is adapted to the cause.
The plastic top is cut and opened-up to accept the inlet elbow; a length of flex pipe is pushed on to get the oily air to the bottom of the bottle; and steel wool added around the tube to trap the oil droplets while the 'clean' air passes back up to the side mounted elbow which has a length of flex pipe added to drop to the chassis about the lower wishbone area:




The bottle will be mounted in its own clip, in turn mounted onto 2 very convienient bolt holes in the inner wing. You might see the bracketry here:


I don't think that's too clear, so will post a finished pic tomorrow when various silicon joints are fully set.

Total cost has been about £25, noe that's a first, something cheap on this car

D/P to go on tomorrow, the TMIC and an oil change using real Sti filters, what a treat!

Graham.

911

Today has been the classic 5 steps forward, and 2 back!

Firstly here's some pics of the finished engine breather 'system':



This morning saw the cat/wrapped D/P back on. This was a surprise as it 'fell-on' so to speak, never had that happen before!:



The heat shield needed a lot more steel cutting out to clear the wrapping, but all the other loose bits went on.
Did the oil change, cranked the engine the proper way, and I thought that the TMIC was all that separated me from starting it up.......

But, yet ANOTHER hose has stopped me dead in my tracks.
The 90 deg elbow from the 'Y' piece off the TMIC to the turbo outlet is too short by 15mm.
So it is another order to Demon Tweeks and another £20 to get to the end of Phase One.

Phase 2 had better be easy, but someone else will be doing the work (Andy F mapping )

Nearly there, feeling a bit ....

Graham.

Tone Loc

iTrader: (1)

Looking at your diagram for the breathers... personally i'd get two inlets into the plastic tank. Reason being that the tee you have with the crank case and rocker covers could just 'short circuit' you system. I.e while under boost i'd expect the crankcase to be blowing air out while replacement air enters the engine by the rocker covers (or that's how subaru explain it in their manual) so this dirty air could just circulate round this tee section and not go any where near the catch tank.

Tony.

Tone Loc

iTrader: (1)

This is what i mean:



Tony.

RaymondH

Following on from this, with two breathers going to the catch tank the rockers will be taking in air from the tank as the crankcase expels it so is it a good idea to have steel wool in the tank in case any of it gets sucked back in? I left mine empty for this reason. In fact, when I think about it, would it not be better to vent the rockers to atmo via a filter and the crankcase to the tank to stop 'dirty' air from being taken back in?

911

OK, understand, but the reason for the pipes is to stop the oil mist getting into the inlet and killing the octane rating.
To ensure 'clean' air being circulated, cant i simply fit a filter into the pipe from the tank to the chassis?
And air drawn into the system would then be cleaned by the filter?
Infact, couldn't I use a garden petrol lawn mower filter, ie dense foam?

Thanks for comments, always interesting!
Graham..

Tim W

iTrader: (1)

Graham, most catch can kit's are supplied with a breather filter for the vent on the can. I didn't bother with my breather system which was a crude version of what you did using a piece of pipe from the crank to the (identical Halfords) water bottle through some wire wool and a second pipe to the bottle from the siamesed cam cover breathers (both of which have an internal one way valve/filter IIRC). THe Filter is a K&N unit costs about 20 quid, and I used on on my ISCV (Link ECU ie no MAF)

Latterly I got lazy and just ran the pipe into my inner wing and onto the road bad Tim

This time I'm going to do the job properly, I may know where to get a Helix style kit for less than 50 quid, which is only a few miles from where the car is residing at present

AndrewC

I think Bob explains the recirculation problem in Andy's PCV and Catch Tanks thread linked to earlier, IIRC he uses 2 PCV valves to eliminate the problem.

Andrew...

Peanuts

iTrader: (15)

http://bbs.scoobynet.co.uk/showthrea...&highlight=pcv

I personally run all three breathers down to the road and tied it off on the ARB, no worse than what your putting out with your exhaust, its also fit and forget as you dont need to empty your catch-cans/bottles of pop.

Tim W

iTrader: (1)

BUT, in Graham's case he has got to have a catch can or he won't pass scruitineering

N.B. in theory venting breathers to atmosphere is an MOT failure point.

David_Wallis

Legacyturbs sells cheap breather filters..

Can find him on ebay as supercarsbaby or on 22b.com as legacyturbs (as here)

911

From the above, it seems that the system I've spliced together is OK, but I could do better!
Scares me when I see a response from JB! Gulp, I must have done something stupid comes to mind !!

Ordered another Samco from DT today for the TMIC and a date is set for Phase 2, AndyF mapping.....

Graham.

P20SPD

iTrader: (1)

Excellent Graham, the way your posts come across are superb, you get frustrated with little obstacles you come across, but your actually enjoying every single minute of it.

Reminds me of when i did my major mods, 1st time around, and the feeling of being young again and like a kid waiting for christmas

Enjoy it, and i hope you have an excellent season hill climbing. If you do Harewood, drop me a mail, and i will come across to watch and have a chat.

Steven

911

Harewood is on the list this year as I'm doing the 'Leaders Championship' this time to spread my wings a bit outside of the Midlands.
That track is awsome, particularly through the farmyard.........................

Can't wait!

Graham

dowser

I simply cannot believe you are using that downpipe

Richard

AndrewC

I did a driver training day at Harewood last year, it is an amazing track. The last section requires a lot of confidence/bravery, and clipping the rev limiter coming through the farmyard turns a few heads

I'd like to see your car in action aswell

Andrew...

911

At this point in time I would like to see it in action too!
The regulations for the first meetings are now on the dining room table and my engine is not yet ready

As to the d/p:

It is an experiment really. If it works ok, drives ok, and passes the MoT ok then it stays on.
If not, then a Milteck cat d/p will go on.
The Magnex d/p that came off looks as bad as that old cat pipe, and the car ran well.

The debate on double tube/open neck wastegate internal deflector etc on d/p's seems to be fuelled by opinion and not technical evaluation.
As much as anything, I think ease of manufacture plays a big part in the design.
The current 3'' pipe cut to accept a wide 'u' shaped side port which welds simply to the neck flange is very simple to fabricate, but the real issue here is the flow via the cat more than the neck design.
At the Autosport Show, many manufacturers were showing cat Impreza systems.
Could say this is the sign of the times (tighter legislations/green issue) or another $$$$ spinner for the decat boys (includes me) to spend £550 replacing their £250 decat d/p's.

I just want to run a clean running car in Competition, especially as the car won't be the cleanest after all this work on it.

Will I notice the 10 bhp or so loss?

Not sure,
Graham

StickyMicky

yesterday i was going to fit my samco while at work, on rembering this above quote i took of my maf and the short flexi tubing and tried to push the tubing over the samco inlet to find it a VERY tight fit, infact it was so tight i didnt actualy get it on properlly.

thought i might have toslightly cut it a tad or sumthing to help it slide on?

good job i didnt butcher my standerd inlet and end up makeing me stranded at work

Floyd

iTrader: (9)

My Samco was a tight fit too but it did go on with some lubricant. I doubt it will leak though!

IMO the best DP design is an open neck with a square splitter to match your choice of turbo (VF and TD are different depths).

F

911

Floyd, totally agree, but a new cat D/P is £500 and I've got Andy F coming to map the car so it will need to wait.
That Samco is rediculous, and mine was so tight even with some vaseline on the mating surfaces it went on and when released it slowly eased and poped its way off!!
I put the clip back on and quickly tightened and all is well.
It will not leak.

Waiting for the TMIC elbow now, and hoping to fire it up on saturday.....

Graham.

Jay m A

iTrader: (2)

Can't you have a centre section sports cat?

If the neck of the cat downpipe isn't of good design ten you may get boost creep

911

If I get any of that kind of thing the D/P will be off and a Miltek cat D/P will be on.
But what exactly is Boost creep related to the d/p neck design?

Is this another term for 'surge'?

Graham.

Jay m A

iTrader: (2)

I'm probably not the best qualified, but as I see it when on boost the wastegate 'penny' has to open (on a duty cycle) and gasses have to flow past it as it maintains a certain boost level. If for any reason the wastegate cannot flow enough of the exhaust gas, then too much will go through the turbo, increasing boost over the target level - boost creep. It has been seen that some twin dump DP's with tongue do suffer from creep because the penny literally blocks flow because its only a bit smaller than the enclosed wastegate section of the down pipe, Simarlarly creep can occour if the wastegate section is blocked (OE) and gasses have to turn through 90 degrees into the turbo exit flow (no tongue).

This is why its pretty much regarded that an open neck DP is the best solution if you suffer from boost creep, tongues (if any) in these are very short, I assume to stop natural deflection by the wastegate into the turbo exit flow. Not sure how much of a difference that makes though.

If any of this is tosh I'm sure many of the experts will comment!