Brake Servo hoses
Discussion
Can anyone tell me which of these hoses is the in / out let for the brake servo in the wing and where do the each connect to on the RV8.
Not even sure why there are two - one vacuum and one air intake?
Need to connect these to similar places on my new engine.
>>> Edited by jellison on Friday 8th April 08:00
Not even sure why there are two - one vacuum and one air intake?
Need to connect these to similar places on my new engine.
>>> Edited by jellison on Friday 8th April 08:00
What has the carbon cannister got to do with cats?
Its for venting the petrol tank, and then allowing the gasses to be burnt (Evaporative Emissions)
As posted in general:
Brake servo is the rear one, the front one is the pipe to the carbon canister purge valve, both are connected directly into the plenum. Vacuum is supplied to the servo, and the carbon can 'sucked out' when the purge valve is opened (ecu controlled by burst @3500rpm when warm & accelerating IIRC).
Dave
Its for venting the petrol tank, and then allowing the gasses to be burnt (Evaporative Emissions)
As posted in general:
Brake servo is the rear one, the front one is the pipe to the carbon canister purge valve, both are connected directly into the plenum. Vacuum is supplied to the servo, and the carbon can 'sucked out' when the purge valve is opened (ecu controlled by burst @3500rpm when warm & accelerating IIRC).
Dave
Not sure which position it goes through the inner wing at (not got the Chimaera now), but I replaced the hose from the front of my servo - this hose should be connected to the side of the inlet plenum.
I don't remember there being a second hose to the servo - just the one to create vacuum which fits on the end. I think the other hose is the return to the carbon cannister as has been said.
I don't remember there being a second hose to the servo - just the one to create vacuum which fits on the end. I think the other hose is the return to the carbon cannister as has been said.
OK - so let me get this right the Rear one in the pic is the vaccum so connect to the vaccum pipe on the back of my LS inlet manifold.
The front one is for a CARBON CANNISTER?! Could this be connected to the same point on a none Rover engine?
(I am loosing the pre-cats but keeping the Main cat), it vents the fuel tank.
Jon
The front one is for a CARBON CANNISTER?! Could this be connected to the same point on a none Rover engine?
(I am loosing the pre-cats but keeping the Main cat), it vents the fuel tank.
Jon
The tank vents through the carbon cannister, that is all ok.
The purge valve, when activated, allows the 'stored' vapours to be cleared by sucking into the plenum - and being burnt off.
If your new ecu supports purge valve, connect it. If you have no purge valve control think of another way - you might end up with a pool of petrol in your front wing otherwise.
Even a dash switch operating the purge valve to occasionally "flush" the can would work. Otherwise re-design the tank venting in mind of pressures (filler cap) and smells.
Dave
PS I have noticed the megasquirt chaps don't seem to cover this, a big + for the VEMS derivative in my book
The purge valve, when activated, allows the 'stored' vapours to be cleared by sucking into the plenum - and being burnt off.
If your new ecu supports purge valve, connect it. If you have no purge valve control think of another way - you might end up with a pool of petrol in your front wing otherwise.
Even a dash switch operating the purge valve to occasionally "flush" the can would work. Otherwise re-design the tank venting in mind of pressures (filler cap) and smells.
Dave
PS I have noticed the megasquirt chaps don't seem to cover this, a big + for the VEMS derivative in my book
Jon, it has nothing to with fuel delivery, for the sake of clarity I shall try & explain my understanding of this subsystem.
Simply it replaces the pinhole in the filler cap, to allow air in as the petrol goes down. In addition it traps any petrol vapour in the can. This will build up & overflow unless something is done with it. The Engine management occassionally trigers a solenoid valve (purge valve) which allows this excess fuel vapour to be sucked directly into the plenum and burnt off.
So the carbon canister has commonly 3 connections. Vent pipe to the petrol tank (this connects near the fuel filler neck on the TVR). Overflow/breather pipe (not all have these - some are just a 'stub' at the bottom). Connection to the purge valve (which may be integrated or a separate component - TVR & LR have used both). The Purge valve is then connected directly to the plenum, by a pipe with a hole in the middle (what the hell is a solid pipe???)
With Lucas systems the ECU triggers the purge valve to open, briefly when engine is at operating temps, and accelerating at about 3500rpm or the like. The captured fumes/gasses from the carbon can are then mixed with the fuel/air in the plenum (due to the sucking of the engine) and burnt in the engine.
Hope thats reasonably clear?
Since you are changing engine, particularly ECU you can do whatever you like, simplest is to be able to control purge valve as in current system, hardest is to rip it all out & vent the tank some other way (don't think you have to meet legislative requirements the same as initial manufacture in this respect).
Dave
Simply it replaces the pinhole in the filler cap, to allow air in as the petrol goes down. In addition it traps any petrol vapour in the can. This will build up & overflow unless something is done with it. The Engine management occassionally trigers a solenoid valve (purge valve) which allows this excess fuel vapour to be sucked directly into the plenum and burnt off.
So the carbon canister has commonly 3 connections. Vent pipe to the petrol tank (this connects near the fuel filler neck on the TVR). Overflow/breather pipe (not all have these - some are just a 'stub' at the bottom). Connection to the purge valve (which may be integrated or a separate component - TVR & LR have used both). The Purge valve is then connected directly to the plenum, by a pipe with a hole in the middle (what the hell is a solid pipe???)
With Lucas systems the ECU triggers the purge valve to open, briefly when engine is at operating temps, and accelerating at about 3500rpm or the like. The captured fumes/gasses from the carbon can are then mixed with the fuel/air in the plenum (due to the sucking of the engine) and burnt in the engine.
Hope thats reasonably clear?
Since you are changing engine, particularly ECU you can do whatever you like, simplest is to be able to control purge valve as in current system, hardest is to rip it all out & vent the tank some other way (don't think you have to meet legislative requirements the same as initial manufacture in this respect).
Dave
As I understand it, all the purge valve does is draw fresh air in through the carbon cannister to 'clean' the absorbed hydrocarbons out of the cannister. It isn't involved in letting air into the tank to replace petrol that is used up. I've deleted the purge valve on mine and it has made no difference (except that presumably the emissions when parked are worse).
Peter, As I understand it, the tank is sealed apart from thru the carbon canister. If that is correct it is implicitly the only way air can replace the volume of fuel used.
I've heard stories of saturated carbon canisters being renewed due to inoperative purgeing, they are not supposed to be consumables like air filters.
I believe petrol liquid is fairly harmless - but the air / petrol mix is a bit more risky, so I'd rather not take any chances, but each to his own.
Dave
I've heard stories of saturated carbon canisters being renewed due to inoperative purgeing, they are not supposed to be consumables like air filters.
I believe petrol liquid is fairly harmless - but the air / petrol mix is a bit more risky, so I'd rather not take any chances, but each to his own.
Dave
I think there is an attachment on the LHS ( RHS if standing viewing the engine )of the engine/inlet manifold.
Its a brass coloured, just behind the TB. From what I recall when stripping stuff of my engine, there was a pipe with a solenoid attached, which I assume was the purge solenoid.
Im not 100% sure if that is correct, as I think it would be strange to attach it to the inlet manifold, rather that somewhere before the TB.
See in this pic I have circled red. You can clearly see the fuel lines. One feeds the rails, the other is the vent line, which attaches to a solenoid ( circled ) and then into teh inlet manifold where I mentioned ( also circled )
Its a brass coloured, just behind the TB. From what I recall when stripping stuff of my engine, there was a pipe with a solenoid attached, which I assume was the purge solenoid.
Im not 100% sure if that is correct, as I think it would be strange to attach it to the inlet manifold, rather that somewhere before the TB.
See in this pic I have circled red. You can clearly see the fuel lines. One feeds the rails, the other is the vent line, which attaches to a solenoid ( circled ) and then into teh inlet manifold where I mentioned ( also circled )
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