Houghton

iTrader: (1)

Hi
Inspired by 911's project thread, I've removed the inlet manifold from my STi3 to do a couple of mods and would appreciate a bit of advice please

Parallel fuel feeds:
1) I see that some people just cut the metal tube and then jubilee clip the rubber hose with tee onto the cut ends. Is this secure enough with the pressures involved?

2) Also some advocate cutting the tubes right back, but how far? Is there any (dis)advantage to taking the hose across the top of the manifold rather than underneath?

Carbon Canister:
I've already removed this and teed the 3 pipes together (2 from top & 1 from bottom). Now I can see what's going on under the manifold
1) Can I do away with the small solenoid valve between manifold & canister and if so, can the plug just be left unconnected?
2) What do I do with the vent pipe? Does this vent the tank or the canister?
3) Do I plug it where it connects near to the fuel filter or vent it somewhere?
4) Presumably the lower pipe that disappears into the inner wing is open to atmos?

Recirc. Dump valve:
Having made redundant most of the pipes under the manifold I'm left with just the large recirc pipe. Is there a better way to return this so I can remove all the clutter under there:

Throttle body water supply:
Removing hot water supply from the T/B seems sensible but:
1) Do I keep the supply onto the Idle valve or remove that supply also?

Sorry for so many Qs.
Think that's all (for now) just off to Halfords for some fuel pipe and tees (if they have it).

Thanks for any help.
Gerry

911

Gerry, it is all in my thread, but some comments for what they are worth:
Once I started i just removed as much of the redundant piework as I could, but i was adding the FPR mod too.
I blanked the tank vnt, but someone added recently that it might be good to drill a small ie 2mm dia hole in the filler cap to allow the tank to vent.
I've done some good miles on the converted car, and all seems well with all the mods I've done (without drilling the Cap)

The essential thing is to keep all the pipes as equal length as possible/practical, so to run the pipes/T's/etc over the manifold should be ok.

The clips I used were NOT the stiff ugly 'Jubilee' type, but thin stainless types. This will ensure that the possibility of leaks is minimised. I was very worried about leaks anywhere, but I tested the system at 3 bar and all is ok.

I would NOT remove the water to the idle valve/throttle body. It is there to help prevent icing of the parts in the winter, and your car is a (great!) daily driver. Not worth it IMHO.

I removed the whole canister thing, pipes etc and all is well.

The trick is to take your time and keep everything as stock looking as possible. i cut all my pipes to ensure I could re-use as much Subaru bracing points to prevent vibration/fatigue etc.
Have you seen Flat4's paraellel mod? I think he did his better than mine (sod!) but common sense is the key.

Good luck!

Graham.

Houghton

iTrader: (1)

Hi Graham,

Thanks for your reply. I did read your thread (honest ) but didn't realise you'd gone into that detail, I'll go through it again and see what I've missed.

The fuel pressure is a concern as I have 4.0 bar @ idle so 5.5 bar potential in system. I see your cut ends were plain, i.e. no hose barb but as you kept the cuts short, there's less chance for the rubber section to blow off. I was thinking of cutting out the steel and running the hose over the manifold (minimise bends/restrictions). I suppose, to do the job properly, it should be Aeroquip reinforced hose & fittings but as usual it's a rush (booked a track day with MLR for this Friday).

I'll do a search for Flat4s mod. The more ideas the better, although too many options tends to confuse .

Cheers, nice to hear your car's keeping the smile broad as ever

Gerry