Aparently the pictures are not visible here, you can not see what I did for the restrictor.
Check if you can see them here:
https://photos.app.goo.gl/zFFCSiPiLdjZHmNJ7
I will post individual diameter pictures later, from the fitting, the hose and the T fitting.

The thread on NASIOC:
https://forums.nasioc.com/forums/sho...882734&page=12

 

10mm dia dom kit.

10.3mm for the gen subaru part - but that was for the second turbo.

 

Hard to say which size to go with but imagine keeping between 8 and 10mm and you'll be alright, now just trying to decide which size to restrict it to, wonder what size fuji will go with, really needs more data taken than what Dom did but that would require a load more investment closer to 8 should keep the other cylinders a bit cooler and coolant lower, added in that the pump is on the cylinder 4 side of the engine might be better to have a the 8 over the 10,so many variables with testing it's hard to say. Need someone to win euro millions and spend some money for real proper testing with results

 

Pedro what internal diameter pipe are you using and what size of the restriction? Do you get issues of cabin heaters when on max dropping in temp a little when sat idling for a couple of minutes

 

Seem to recall somewhere that there was an AN6 fitting used.

 

With an an6 fitting don't see why he'd need to reduce size, as that's around 8mm Id

 

In post 56 he was saying the supplied fittings where too big so just said that I had read somewhere that AN6 was supposed to be the optimal size
Too large would be detrimental to the other cylinders.

 

Yeah I get that and the one in America with lots of testing is slightly bigger at a 10mm hole just wondering how his with the reducer is performing as its what I've done

 

IMHO if anyone wants to do this mod they'd be better going a bit smaller than too big. Half a loaf is better than none.

 

Totally agree. Would rather the ID was smaller and the part was having less of an effect rather than causing other more serious problems. Personally I'd stick with the 8mm ID rule.

 

Well ive got an 8.5 reducer in and still causing issues been told by mapper it's still too big by a couple mm but obviously won't tell me exactly what there's is so going smaller again

 

As above 6mm ID T piece would cure all your problems.

 

So looks like the FB Tuning kit uses one of these then:

https://www.ebay.co.uk/itm/6mm-Brass...kAAOSwukZcUErn

 

Quite possible but in hindsight if you had a 6mm barb on one side it would be better than restricting the heater hose as such. You can get them for I have a couple here.
Or a 6mm reducer in the head.

 

Example. Would be better in brass

https://www.ebay.co.uk/itm/10X-6mm-t...item4d94efa01f

 

Yep, totally get what you're saying. Would maintain the original pipe flow and only slow the new port down.

 

 

Fb tuning doesn't use heater hose pipes so it doesn't restrict that it goes into the throttle body lines when you read the website post, not sure exactly on what difference this makes though to affecting flow and such in the system

 

Shouldn't matter where you break into the heater hose should it? Aslong as it's the correct one, see a lot teeing in right by the hard pipe but because of way mine is don't with a 45 piece I've broken in further up

 

You are correct but ultimately it does enter the heater hoses. Most people do the throttle bypass mod in which case it could be tee'd into that. But don't know how the heater would react it should be ok.

 

Going by the diagrams on the vems page that would put it back into the system before the heater correct? As all the heater is is a heat exchanger basically would that not be better to bring temps down marginally as the mod raises it due to diverting some away from the rad? Or not gonna make a difference

 

Can't answer that I'm afraid would need a flow chart.

 

Guys, I've added pics of all internal diameter the the google album, you can check it out. As I suspected, it's way to large.
I'll install 2 8mm reducers on the longer silicone pipe, one imediatly after the block exit fitting and other imediatly beforebtue T fitting.

 

Do you think more reducers is going to help? 3 surely one decent length of reducer will reduce the flow down? I suppose not as good as full length of hose that diameter but still, I'm gonna try a 6mm reducer about 30mm long

 

Did the mapper tell you what they couldn't achieve? But, they related this problem to the cylinder cooling kit?
Had they seen this issue before?

 

Said that being too big will affect the flow of the whole system so could cause my fans blowing colder on idle than when at revs, so seeing other things in this thread I'm trying a 6mm reducer

 

Hmm Interesting comment , (Henrik May) but why would Subaru have water cooled the Turbo then ?
Would the turbo heat in the casting not be best taken away with water ?
& without would you not end up running hotter gas through it , thereby increasing charge temp ?

Although I follow the need to reduce temp for No 4 Pot, Any water flow compensation to do this makes sense.
"it feels" to me the Americans have been breaking more 2.5ltr Ring lands since 06 than UK,
Might this be influenced by Octane / Fuel type exposing them to more Pot 4 fails and the 2,5 fragility ?

Has anyone ever thought of checking the knock on No 4 and perhaps 2 in parallel as an addition to the standard knock sensor before and after the proposed mod ?
I wonder also if after flow measuring your injectors would it make sense to put the one that flows most into pot 4 ,
even one that flowed 1-2 percent more might help run that cylinder slightly cooler ?

 

I've added more pics on the Google photos album, you can see the ebay kit installed.
I've been running mine for 3days. I've installed 3 reducers on the silicone pipe with ~7mm internal diameter.
I can't say I notice any changes... If there is any is that the fan is more active when ideling. Seems to come on more frequently. I was talking with a friend left the car ideling... fan went on a 3-4 times in 20min. But it might be me just trying to find a difference.


Air temperature might be an issue. The UK has generally colder air temp.
I'm from Portugal, I've done a trackday with 40º ambient temp, the car held up pretty well, but I don't have the bottm plastic cover neither any cover on the bonnet.

 

I would be wary of taking any cover off , especially from under the engine, firstly you will muck up the aerodynamics , the front end will loose considerable downforce.
You will also change the flow of air direction and relative pressure in the engine bay , I'm certain that wont help your IC keep the charge temp or your track times down.
Indirectly it causes the engine management to pull ignition times and fueling backward, and that paradoxically causes less power and heat to be generated.

If you are worried about ambient heat it would make sense to lag wrap the downpipe exhaust and turbo and then ensure the radiator is clear of any obstruction such as leaves
This will assist the liquid cooling to do its job,

 

Downpipe is wrapped...
Been running without the the bottom cover for 5+ years
Car has good power, has reached 250Km/h would go more but I'm a sissy... and doing that speed on an MY99 car, is not for me anymore.

No issues on temperatures.