Vehicle & Technical > Defender
300tdi torque and bhp figures?
Magnum335:
--- Quote ---Yes these are a 52mm gauge
Thanks
--- End quote ---
52mm it is then!
Porny:
--- Quote from: "barnyfarmer" ---It must be a 52mm..... Exactly how far away are you from me lol?
--- End quote ---
Depends where you are :wink: .... I'm near Junc 9 of the M42.
--- Quote from: "barnyfarmer" ---
I might go for that nissan one i think....
VDO is the only one that doesnt do -ve. Can you get -ve pressure if you tap straight into the manifold?
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Nope, you will never, ever get a vacuum on a diesel (excluding some early Series 3's before we get someone being clever - but we'll exclude them for the time being)....
A quick explanation (sorry if this is really basic)
You won't get a vacuum on a diesel because you do not have a throttle blade,
On a petrol engine, the vacuum is created when you shut the throttle (i.e. lift of the accelerator pedal) as the engine is still trying to suck in air, but as the throttle blade is closed, there is only a small amount of air available. The engine is basically trying to get more air than is available so creates a vacuum in the inlet manifold.
A diesel though, does not have a throttle blade – a diesel basically runs WOT [Wide Open Throttle] all the time and all the accelerator pedal does is add or remove diesel.
So you will not see a vacuum even in the inlet manifold, as it can not physically create one. Hence why you have a vacuum pump on the side of the engine to supply a vacuum to the brake servo.
In terms of dump valves:
A dump valve is mainly used with high boost applications, the back pressure caused by lifting off the accelerator can cause the compressor within the turbo to stall. In extreme cases, the compressor can actually shatter.
This back pressure occurs because when you lift off the accelerator, the throttle blade closes... and as the turbo is still producing boost pressure this pressure builds up behind the turbo has no where to go - which as mentioned - in extreme cases can cause the compressor wheel within the turbo to go bang!!! - not good.
The dump valve is simply a release for this pressure... which also reduces turbo lag as the turbo is pressuring into a now empty intake manifold - which will also have a slight depression/vacuum acting on it.
A diesel though, does not have a throttle blade and as such will never see this build up of 'back' pressure.... (as mentioned a diesel basically runs WOT all the time and all the accelerator pedal does is add or remove diesel - in simple terms)
Which also means connecting a dump valve to a diesel is a little more complicated. Because it doesn't have a throttle blade, there is no-where to tap into to connect the dump valve - which relies on the pressure difference before and after the throttle blade to work.
The only vacuum created on a diesel is for the brake servo.... a diesel dump valve gets plumbed in to the vacuum circuit and is controlled by a solenoid valve that is activated when you lift off the accelerator pedal. However.... this set up will work ok on a 200Tdi or 300Tdi but is not really ideal for a TD5.
Whilst a dump valve can be made to work on a diesel, the only benefit would be that of noise.
Unlike a petrol, you will see no reduction in turbo lag, or turbo lifespan.... the biggest killer of turbo is not allowing them to warm up or cool correctly - i.e. thrashing the car from cold or turning it straight off after a high speed thrash. Worst still is when people rev the engine and then turn it straight off.
Ian
Magnum335:
You are a very wise and knowledgable man.
Cheers for taking the time to explain it all to me.
Well the Equus is ordered so will see what it is like when it turns up! It has to be an improvement on my rattley tin can of a guage i have at the moment! And will hopefully blend in a bit better, though the TIM was not to bad.
I am near junction23a of M1. i have no idea where that is in ralation to M42 as i am not from round here!!!
Porny:
--- Quote from: "barnyfarmer" ---You are a very wise and knowledgable man.
Cheers for taking the time to explain it all to me.
Well the Equus is ordered so will see what it is like when it turns up! It has to be an improvement on my rattley tin can of a guage i have at the moment! And will hopefully blend in a bit better, though the TIM was not to bad.
I am near junction23a of M1. i have no idea where that is in ralation to M42 as i am not from round here!!!
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No probs....
I do sort of mess with engines for a living.... :wink:
Junc 23a of the M1 is the Junction with the A42 (which is end of the M42) so you are about 30 mins from me (my brother lives at Long Eaton - Junc 25 of the M1) and that takes about 40/45mins from mine.
If you ever need a hand with anything give me a shout.
Ian
Range Rover Blues:
I just watched the vid and I think that sounds sweet, who said chav? no comparison.
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