Passed MOT, been told of a 'Turbo' boost???

Well, that's another MOT passed with flying colours. '97 Discovery 300
Tdi with 90k ish on the clock now.

Just changed, last week 'cos one was pitted and weeping slightly, swivels,
seals and oil for grease and the front end's a lot cleaner now ..

Whilst at the MOT place I got talking to someone who says he's worked on the
300 (and 200) Tdi engine and suggested that because my emissions are so low
that it'd be worth me changing the point at which the turbo comes in so that
it comes in a few hundred rpm lower. He reckoned this could be done by
'adjusting' the turbo activation rod, which uses a rose-joint and
thread/lock-nut arrangement. He also reckoned, and it seems plausible, that
this would increase acceleration and towing power, we do toe _a lot_ and
wouldn't really affect fuel consumption a lot.

So my question is/are ...

Has anyone done this?
Is it worthwhile?
Were there any downsides to it?
Is it as easy as he suggested it to be?

I've looked in the Rave manuals and there is indeed an activation rod and it
does indeed appear to be adjustable, but it seems to need the manifold and
turbo removing to get to it, so isn't, at first glance, an 'easy' tweak and
test and re-tweak and re-test fiddle about. I only looked from the top of
the engine though, and being hot I didn't feel about a bit to see what my
fingers might see/feel.

I'd appreciate advice/scorn/tales of great tidings/t o g woe ..

--
Paul ...
(8(|) Homer Rules ..... Doh !!!

"Paul - xxx" <[email protected]> wrote in message
news:[email protected]...
> Well, that's another MOT passed with flying colours. '97 Discovery
> 300 Tdi with 90k ish on the clock now.
>
> Just changed, last week 'cos one was pitted and weeping slightly, swivels,
> seals and oil for grease and the front end's a lot cleaner now ..
>
> Whilst at the MOT place I got talking to someone who says he's worked on
> the 300 (and 200) Tdi engine and suggested that because my emissions are
> so low that it'd be worth me changing the point at which the turbo comes
> in so that it comes in a few hundred rpm lower. He reckoned this could be
> done by 'adjusting' the turbo activation rod, which uses a rose-joint and
> thread/lock-nut arrangement. He also reckoned, and it seems plausible,
> that this would increase acceleration and towing power, we do toe _a lot_
> and wouldn't really affect fuel consumption a lot.
>
> So my question is/are ...
>
> Has anyone done this?
> Is it worthwhile?
> Were there any downsides to it?
> Is it as easy as he suggested it to be?
>
> I've looked in the Rave manuals and there is indeed an activation rod and
> it does indeed appear to be adjustable, but it seems to need the manifold
> and turbo removing to get to it, so isn't, at first glance, an 'easy'
> tweak and test and re-tweak and re-test fiddle about. I only looked from
> the top of the engine though, and being hot I didn't feel about a bit to
> see what my fingers might see/feel.
>
> I'd appreciate advice/scorn/tales of great tidings/t o g woe ..

It doesn't necessarily make the turbo spool up at a lower rpm, but it will
give more boost. All you are doing is adjusting the turbo wastegate (bypass
valve) to operate at a different boost level. To make a turbo spool up at a
lower rpm needs a different turbine housing throat area, smaller in this
case, and that would restrict high rpm/boost gas flow. If your engine has
"available oxygen" then you can add more fuel, this increased combustion
will increase the exhaust gas flow at a given rpm, therefore increasing
turbine rpm and hence boost.
Badger.

Paul - xxx wrote:

> So my question is/are ...
>
> Has anyone done this?
> Is it worthwhile?
> Were there any downsides to it?
> Is it as easy as he suggested it to be?
>

Paul,
Take a look at the thread "Defender 200Tdi Fuel Pump Timing" we had here
in the last couple of days - there is more information on doing this
than you could ever need to know.

Steve

>
> Whilst at the MOT place I got talking to someone who says he's worked on
the
> 300 (and 200) Tdi engine and suggested that because my emissions are so
low
> that it'd be worth me changing the point at which the turbo comes in so
that
> it comes in a few hundred rpm lower. He reckoned this could be done by
> 'adjusting' the turbo activation rod, which uses a rose-joint and
> thread/lock-nut arrangement. He also reckoned, and it seems plausible,
that
> this would increase acceleration and towing power, we do toe _a lot_ and
> wouldn't really affect fuel consumption a lot.
>
>
He hasn't a clue what he is talking about!

The 'turbo activation rod' as he calls it is actually the wastegate
actuator, it makes no difference whatsoever to the point where the turbo
comes in. What it does do is control the maximum boost pressure.
Also, if your emissions are low, this would suggest that there is already
plenty of air going through there, adding boost simply adds more air, and
would not make the slightest difference to power.

As someone has said, read the "Defender 200Tdi Fuel Pump Timing" thread,
there are links on there which will tell you everything you need to know.

Badger came up with the following;:
> "Paul - xxx" <[email protected]> wrote in message

>> I'd appreciate advice/scorn/tales of great tidings/t o g woe ..
>
> It doesn't necessarily make the turbo spool up at a lower rpm, but it will
> give more boost. All you are doing is adjusting the turbo wastegate
> (bypass valve) to operate at a different boost level. To make a turbo
> spool up at a lower rpm needs a different turbine housing throat area,
> smaller in this case, and that would restrict high rpm/boost gas flow. If
> your engine has "available oxygen" then you can add more fuel, this
> increased combustion will increase the exhaust gas flow at a given rpm,
> therefore increasing turbine rpm and hence boost.
> Badger.

Thanks.

--
Paul ...
(8(|) Homer Rules ..... Doh !!!

steve Taylor came up with the following;:
> Paul - xxx wrote:
>
>> So my question is/are ...
>>
>> Has anyone done this?
>> Is it worthwhile?
>> Were there any downsides to it?
>> Is it as easy as he suggested it to be?
>>
>
> Paul,
> Take a look at the thread "Defender 200Tdi Fuel Pump Timing" we had here
> in the last couple of days - there is more information on doing this
> than you could ever need to know.

Heheheheh, yeah thanks. I must admit to 'missing' the thread ...

--
Paul ...
(8(|) Homer Rules ..... Doh !!!

SimonJ came up with the following;:
>> Whilst at the MOT place I got talking to someone who says he's worked on
> the
>> 300 (and 200) Tdi engine and suggested that because my emissions are so
> low
>> that it'd be worth me changing the point at which the turbo comes in so
> that
>> it comes in a few hundred rpm lower. He reckoned this could be done by
>> 'adjusting' the turbo activation rod, which uses a rose-joint and
>> thread/lock-nut arrangement. He also reckoned, and it seems plausible,
> that
>> this would increase acceleration and towing power, we do toe _a lot_ and
>> wouldn't really affect fuel consumption a lot.
>>
>>
> He hasn't a clue what he is talking about!
>
> The 'turbo activation rod' as he calls it is actually the wastegate
> actuator, it makes no difference whatsoever to the point where the turbo
> comes in. What it does do is control the maximum boost pressure.
> Also, if your emissions are low, this would suggest that there is already
> plenty of air going through there, adding boost simply adds more air, and
> would not make the slightest difference to power.

Cheers, in fact after re-reading the Rave manuals and looking at it again,
this is what I worked out for myself (pat on back methinks) and reckoned
that to benefit from extra boost it'd also need extra fuel, so would still
need the injection system tweaking to get any real benefit.

> As someone has said, read the "Defender 200Tdi Fuel Pump Timing" thread,
> there are links on there which will tell you everything you need to know.

Yup, am doing ..

--
Paul ...
(8(|) Homer Rules ..... Doh !!!

in order to increase the turbo boost pressure you will basically
shorten the wastegate rod by 6mm .
really though you should have a boost pressure gauge fitted in order
to measure the boost pressure youve increased to , youre looking at 1
bar maximum if you dont want to cook things .

on the injector pump there is small housing on top held down by 4
screws , there is a gold coloured blanking plug on top of this housing
and you can pry it out with screwdriver to reveal a locknut and
adjuster grubscrew .

the grub screw in this housing alters the depth of the fuel metering
rod / diaphragm , this is the smoke adjuster .
some people screw this in one turn for more oomph , others have to
unscrew it to reduce smoke .

the spring under the diaphragm is holding diaphragm up under pressure
and keeping fuel metering to its minimum but when turbo boost pressure
increases it pushes the diaphragm downwards, pushing diaphrgam and
metering rod downwards increasing fuel metering as the revs and boost
increase .

if you screw in the STARWHEEL which is under the diaphragm/spring
assembly this will allow less seat pressure on the spring and thus
less boost needed to move diaphragm initially .

the main point of altering fuel input rate and thus increasing ooomph
is the "full power" adjuster on rear of pump body , on 200tdi it is
high up just under the top housing and on 300tdi ot is closer to the
injector pipe unions on rear of pump.

there may be a tamper proof cover over the locking nut of the adjuster
which youll need to remove .

the adjuster is a 6mm screw thread about 25mm long with slot and
hexagon in end and with a 13mm locknut holding it against the pump body
..

to increase fuel rate you screw this adjuster in , to decrease you
unscrew it .

youll only be looking to make 1/4 turn adjustments and then note
exhaust for black smoke when youre driving , ie under load in 5th gear
uphill at about 50mph and watch for black smoke .
if you get smoke appear then back off the adjuster 1/4 turn at a time
..

the diaphragm it self can be rotated in its seat in the pump, it has a
dot mark on the metal disc holding diaphragm rubber that you use to
line up within housing , 12oclock[ towards rocker cover] is leanest
position and approx 9pm is richest but most people set it somewhere
between 12 and 6 oclock position .

if you shorten the wastegate rod you may need to cut a small amount off
thread on bar to allow shortening of its length , so be carefull what
you do .

there is a tee connector on the plastic pipe running into the housing
on top of iinjector pump , i think you can connect boost pressure gauge
here to read pressure .

if you screw the full load adjuster in on rear of pump it will go like
buggery , but watch the black smoke and MPG .

m0bcg came up with the following;:
> in order to increase the turbo boost pressure you will basically
> shorten the wastegate rod by 6mm .
> really though you should have a boost pressure gauge fitted in order
> to measure the boost pressure youve increased to , youre looking at 1
> bar maximum if you dont want to cook things .

Cheers.

I have now also read the Defender 200Tdi thread ..

--
Paul ...
(8(|) Homer Rules ..... Doh !!!