RHD ITB batterflies...

[zaq123]

I noticed ITBs batterflies having a gap (not fully closed) out of the box. Is it on purpose or just rushed assembly? I get a concept of regular TB gap where it's preset for a reason. These look like good old carb design with hard setting for idle adjustment. If I recall, carb plates are adjusted to zero initially and then gapped with the adjuster screw. Do I need to adjust batterflies to zero initial gap so they all open equally? I understand that I can sync them later with the side links/adjusters but it will be only one adjustment per 2 plates. Want to make sure that all 6 are as close as possible from the start before fine tunning each pair. Or there is a gap for a purpose? Anyone knows what is the purpose and what is the initial gap?

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[zaq123]

in case anyone else is wondering the same thing:
ok DONT adjust them!
they are set to hot running temperatures, because the alloy expands a lot more than the shaft they are sometimes a little bit sticky when they are cold, its perfectly normal and they will settle in after a bit of use. If you they are set to be perfect at cold temperature then when they warm up they will stick open a little causing an annoying high idle all the time


regards

rama

[digger]

I think it says that on the website as I had read it before.
I used the earlier ones previously and with the idle control it would cope with hot vs cold but the icv PW difference was noticeable .

I have the new ones and I noticed the same stickiness. One issue I had with the newer ones was that initially in fully closed it was sticky which makes it more difficult to get each pair full closed for first setup like above but even at the idle position it was still slightly sticky originally. Now it isn't sticky at all though i don't know if that's a good thing or not as it must wear slightly? idk

I haven't touched it in atleast a couple years so all seems good

[zaq123]

I think it says that on the website as I had read it before.
I used the earlier ones previously and with the idle control it would cope with hot vs cold but the icv PW difference was noticeable .

I have the new ones and I noticed the same stickiness. One issue I had with the newer ones was that initially in fully closed it was sticky which makes it more difficult to get each pair full closed for first setup like above but even at the idle position it was still slightly sticky originally. Now it isn't sticky at all though i don't know if that's a good thing or not as it must wear slightly? idk

I haven't touched it in atleast a couple years so all seems good

another question:

how critical is it to maintain the same length vacuum lines from TBs to the vacuum manifold?
I understand the need if one utilizes MAP sensor where equal vacuum pulses are needed. But since we are running these on Alpha-N, is there any other reason to keep vacuum lines the same length?

[digger]

If you're using the vacuum lines for idle then make them the same. Also use same fittings on each I've bought fittings that looked same but the bore was different....if it's not the same then it won't be balanced to each cylinder during idle and low throttle positions

[zaq123]

If you're using the vacuum lines for idle then make them the same. Also use same fittings on each I've bought fittings that looked same but the bore was different....if it's not the same then it won't be balanced to each cylinder during idle and low throttle positions

At some point I will be tuning ICV for closed loop for this setup. All 12 fitting are the same- 8mm, some straight some elbows. RHD kit has 3 cyl sharing the port with the brake booster (via check valve). 3 cyl fitting/line is the same 8mm line but the actual TB port is larger and split to the booster. Will this make a difference for the idle?

[digger]

Not familiar with RHD icv bits but if the smallest fitting is common to all and hoses are equal it should work fine. I think others have used it without issue

[nando]

if you have elbows mixed up with straight pieces, then they aren't the same. An elbow has approximately twice as much restriction as an equal size straight piece.

[zaq123]

if you have elbows mixed up with straight pieces, then they aren't the same. An elbow has approximately twice as much restriction as an equal size straight piece.

not significant enough for the vacuum and in this application

[digger]

It depends how the elbow compares to the min cross section

If the elbow is 6mm ID but there's a straight connector at 3 or 4mm then the 3mm will probably drive the balance. I drilled all my fittings the same kept everything the same as I could. You need bleed screws on each vacuum hose lol

[digger]

not significant enough for the vacuum and in this application

looking at the website its tee with the branch that goes to the booster so its probably going to behave for all intensive purposes the same as a straight connector/screw in nipple.

i just tapped a separate line into the runner for the booster as it keeps the fittings a little shorter, more than one way to skin a cat though

[zaq123]

if you have elbows mixed up with straight pieces, then they aren't the same. An elbow has approximately twice as much restriction as an equal size straight piece.

thanks guys for pointing this out. Made me check elbows vs straights ID and elbows do have smaller ID in the barbed section.

My setup is 6 elbows at the runners (needed to keep clear from the coolant below); 4 straights at the vac block and 2 elbows. Will be drilling those 2 elbows at the block. This way all restrictions are the same. Would you drill out the other 6 at runners to make them larger? Or al long as restrictions are the same it should be ok?

[nando]

I think as long as they are the same it's fine.

[zaq123]

Thanks guys. Elbows drilledout to match straights, lines are all the same length (fittings included, measured from runner to the manifold); everything arranged not to rub/touch anything. Was a little tricky as RHD block is a little small. Had to make the mounting bracket for it too and drill/tap for the mounting (block has some meat in corners without the drilling Into the chamber). Wish RHD made the vacuum manifold nice and long, similar to the fuel rail; would be a much better arrangement with short lines. Had to also come up with the bracket to keep main harness/coolant line/injector harness plug bracket in place.



Manifold box doesn’t interfere

[nando]

that looks awesome!