vacuum and boost lines advice

[Discopotatoes]

Im trying to declutter my twin turbo engine bay and reduce the amount of pipes hoses and visible leads.
can i have one vacuum/ boost hose to feed multiple items? instead of individual hoses coming from the inlet
i hope that makes sense.

[227bhp]

No they need to be separate.
Hope that makes sense.

[Discopotatoes]

227bhp said:

No they need to be separate.
Hope that makes sense.

cheers

[GreenV8S]

227bhp said:

No they need to be separate.

Why?

[227bhp]

GreenV8S said:

227bhp said:

No they need to be separate.

Why?

Each one carries a signal, so (if it's important) must come from source, if it gets divided, T'd off etc it becomes diluted and no longer relevant or accurate.

[GreenV8S]

227bhp said:

Each one carries a signal, so (if it's important) must come from source, if it gets divided, T'd off etc it becomes diluted and no longer relevant or accurate.

You mean diluted in the sense of the increased volume tending to smooth out transients a bit more? That's the only effect I can see - and it's not clear why a small volume increase would be a problem.

[AW111]

GreenV8S said:

You mean diluted in the sense of the increased volume tending to smooth out transients a bit more? That's the only effect I can see - and it's not clear why a small volume increase would be a problem.

You definitely want to keep the vacuum for the brake booster seperate, and anything else that uses vacuum as a power source * as that may change the effective vacuum seen by sensors.

• I don't know with your car, but mine uses a vaccum diaphragm for the cruise control; some Fords used vacuum for interior vent operation, some cars use vacuum to open bypass valves, etc.

I doubt yours has vacuum operated wipers or pop-up headlights, which was never a good idea .

[paintman]

With multiple individual hoses if a hose or component fails allowing air in you only lose that component.
With one hose doing them all any failure & you lose the lot.

[GreenV8S]

AW111 said:

You definitely want to keep the vacuum for the brake booster seperate, and anything else that uses vacuum as a power source * as that may change the effective vacuum seen by sensors.

• I don't know with your car, but mine uses a vaccum diaphragm for the cruise control; some Fords used vacuum for interior vent operation, some cars use vacuum to open bypass valves, etc.

I doubt yours has vacuum operated wipers or pop-up headlights, which was never a good idea .

I agree that large vac-powered actuators such as brake servos need to be connected separately. These have a large enough displacement to alter the line pressure and would cause a false reading if sensors shared the same feed. There are also some older vehicles still using vac operated ignition advance which use ported vacuum rather than straight manifold vacuum and these need to be connected correctly and not just teed into any old vac line.

I'm thinking more of the vac sensing lines such as fuel pressure reference, manifold pressure sensor, vac/boost gauge, recirc valve actuator, vac signal to boost controller, where the amount of air being moved is minimal and I don't see any particular need to provide separate connections.

So I can see that there might be some connections which benefit from being kept separate in some situations, but I don't see the justification for the sweeping reply that everything must be kept separate.

[Discopotatoes]

GreenV8S said:

AW111 said:

You definitely want to keep the vacuum for the brake booster seperate, and anything else that uses vacuum as a power source * as that may change the effective vacuum seen by sensors.

• I don't know with your car, but mine uses a vaccum diaphragm for the cruise control; some Fords used vacuum for interior vent operation, some cars use vacuum to open bypass valves, etc.

I doubt yours has vacuum operated wipers or pop-up headlights, which was never a good idea .

I agree that large vac-powered actuators such as brake servos need to be connected separately. These have a large enough displacement to alter the line pressure and would cause a false reading if sensors shared the same feed. There are also some older vehicles still using vac operated ignition advance which use ported vacuum rather than straight manifold vacuum and these need to be connected correctly and not just teed into any old vac line.

I'm thinking more of the vac sensing lines such as fuel pressure reference, manifold pressure sensor, vac/boost gauge, recirc valve actuator, vac signal to boost controller, where the amount of air being moved is minimal and I don't see any particular need to provide separate connections.

So I can see that there might be some connections which benefit from being kept separate in some situations, but I don't see the justification for the sweeping reply that everything must be kept separate.

All I have are brake servo, two turbo actuators a map sensor an n75 valve, blow off valve fuel pressure Reg. And a boost gauge

[stevieturbo]

Discopotatoes said:

All I have are brake servo, two turbo actuators a map sensor an n75 valve, blow off valve fuel pressure Reg. And a boost gauge

IMO w/g or boost control should never come from the intake.

Even more so if you're introducing leaks...ie via that N75 valve.

Obviously servo will need a dedicated large line with a non return valve so it will not see boost.

So in reality, that leaves only 4 items from the intake. For critical items like FPR and MAP, I would prefer to dedicate these.

The boost gauge and BOV...wouldnt be overly concerned, just make sure they dont leak.

If you use push fit pneumatic fittings, 4mm lines are plenty ( maybe 6mm for BOV ) and can be done quite neat and tidy as they are so small.

Or some people like grouping things together using one of those vacuum block thingies. I dont...but some do. Again this should have a decent size hose going to it from the central plenum of the intake.

[andygtt]

Agree with Steve 100%

As an example.
The standard noble has FPR MAP and boost control valve all on one line, brake has its own dedicated as does the boost gauge.

I changed this, now FPR and MAP are one same line (deliberately) from the inlet, boost control valve comes from the turbo itself and I read the boost gauge from the ecu (Ie MAP).

I have a dump valve now (stock car doesn't) and that has its own dedicated feed from the inlet.

[Discopotatoes]

andygtt said:

Agree with Steve 100%

As an example.
The standard noble has FPR MAP and boost control valve all on one line, brake has its own dedicated as does the boost gauge.

I changed this, now FPR and MAP are one same line (deliberately) from the inlet, boost control valve comes from the turbo itself and I read the boost gauge from the ecu (Ie MAP).

I have a dump valve now (stock car doesn't) and that has its own dedicated feed from the inlet.

Thanks Chaps