300tdi need more power

[ross501]

i have a 300tdi disco and will be using it for towing need some more power for the hills drops to about 40 and has no power to get up them any suggestions

[extreme90]

bigger intercooler, but it will make the engine run alot hotter, expecialy in hot weather, and thats without towing  :shock:

just turning the pump up on its own simply wont be enough to satisfy

either leave it as it is where its reliable, fitt a bigger intercooler but run the risk of running hot

or get a bigger tow vehical

[oxymoron]

Hi, I have been running a bigger intercooler for the last 120,000 miles.
You just increse the fuelling when the turbo is on boost via the capsule on top of the injector pump.
Make sure you are getting full throttle travel, I back mine of by about 5% for the rev test on the mot,and it makes it flat as a pancake.
On some long motorway hills it will outpull the newer TD5 discovery,not bad for 185,000 miles!

[karlo]

http://www.fag.hiof.no/~frodehaa/forandringer/Comfy.htm#Increase

[extreme90]

just turning the fueling up on the diaphram is a waste of time and a waste of money on th intercooler
now dont take it the wrong way but u think its fast, put it along side mine or someone elses where its tweaked properly, u wont keep up  :roll:

if your turning the diaphram and leaving the smoke screw, your not getting enough fuel vs the increase amount of air thats entering the cylinders due to it being denser as its cooler becouse of the intercooler

sorry, but your not benifiting

towing it doesnt matter if your doing 40 up a hill, your towing  :roll:
youve got to expect to drop down the box
just like anything else, td5's are the same

we tow a boat all round the country
fully laden its 1.7t

to try and make the 300 disco go better i turned the pump, didnt make a differenct, still the same

if i tow it with my 90, pumping out around 150bhp if not more, it still drops down the box even with all that torque

and it gets too hot for liking and thats with the 8274 off the front for better cooling  :shock:
and also a big pacet fan cooling it

its just a no win for towing

only way to fly up hills is with a dirty big land bruiser,nothing can touch them for towing

thats my opinion and am sticking to it  :roll:

feel free to rant at moan as you please  

[Budgie]

if your turning the diaphram and leaving the smoke screw, your not getting enough fuel vs the increase amount of air thats entering the cylinders due to it being denser as its cooler becouse of the intercooler

Now I maybe wrong here but, I was always told that the smoke screw only increased the initial amount of fuel as it compresses the diaphragm slightly, allowing the pin at the base of the diaphragm shaft to come out a wee bit more than standard. This is for low/no boost conditions.
Once the turbo is up to speed then that takes over and compresses the diaphragm further, increasing the fuel flow as the pin moves out further due to the shape of the offset shaft at the base of the diaphragm.
Thus, once the top of the diaphragm is clear of the bottom of the smoke screw the smoke screw does nothing to increase the fueling of the engine. It's all down to how the diaphragm offset shaft has been positioned and how far out the pin is allowed to go.

Altering the diaphragm and smoke screw will make quite a difference to how the motor drives and it's free to do, but follow the correct instructions and take note of the warnings about the exhaust gas temperatures increasing!! Details are available HERE. I would also clean the inside of the intercooler as this will also help.

You will get even more power if you put a larger intercooler in and if you don't fancy doing the alterations to the injector pump yourself then get the intercooler fitted at the supplier and they will set the pump for you.  

[L90OOK]

Now I maybe wrong here but, I was always told that the smoke screw only increased the initial amount of fuel as it compresses the diaphragm slightly, allowing the pin at the base of the diaphragm shaft to come out a wee bit more than standard. This is for low/no boost conditions.
Once the turbo is up to speed then that takes over and compresses the diaphragm further, increasing the fuel flow as the pin moves out further due to the shape of the offset shaft at the base of the diaphragm.
Thus, once the top of the diaphragm is clear of the bottom of the smoke screw the smoke screw does nothing to increase the fueling of the engine. It's all down to how the diaphragm offset shaft has been positioned and how far out the pin is allowed to go.

Altering the diaphram and smoke screw will make quite a difference to how the motor drives and it's free to do, but follow the correct instructions and take note of the warnings about the exhaust gas temperatures increasing!! Details are available HERE. I would also clean the inside of the intercooler as this will also help

You will get even more power if you put a larger intercooler in and if you don't fancy doing the alterations to the injector pump yourself then get the intercooler fitted at the supplier and they will set the pump for you.  

You are correct!

Biggest gain is to remove the diaphram & put it back in for MOT time (30 second job)  This allows the diaphram to depress another 5mm or so letting more fuel in & reducing turbo lag.
Turning the diaphram will also let more fuel in as it's on a eccentric pin.  I have turned mine 30degrees from standard.
When first taking off the fuel pump diaphram housing ensure you mark it's  "normal position" so you can reset it if needed.
The main fuelling screw is where the most damage to the engine can occur & personally I would leave it well alone.  By turning the main fuelling screw 'in' you are increasing the amount of fuel at all stages, tickover to fuel boost.  With increased fuelling here you are also increasing the Exhaust Gas Temperature (EGT) which is the main reason you will have cooling issues.  A larger intercooler will help to reduce this but a larger intercooler sits infront of the radiator :-s
If you wish to increase the main fuelling then do so by 1/8 turn each time...they need very little adjustment.  Take it for a drive & you should have no more smoke than a mist...not a black trail.  Black smoke is unburnt fuel the engine can't cope with.  Turning up the Main Fuelling screw can seriously damage your engine if you get it wrong!
Larger intercooler will give you a noticable increase in power aslong as its not obstructed by large winch, spots etc...
You can also increase the turbo boost pressure by screwing in the actuator rod...make sure it's no more than 1 bar pressure though.  I know some are boosting at 1.2bar but 1 bar is still safe...especially as allot of Tdi's are getting on now!!

My preference in order of tuning a Tdi is:

1.  Renew air filter...use standard not K&N type
2.  Check throttle is opening all the way when peddle is depressed.
3.  Clean intercooler out with paraffin...ensure dry before replacing.
4.  Check hoses aren't collapsing/delaminated, if so get some silicone ones
5.  Adjust pump diaphram as described above.
6.  Increase turbo boost pressure to 1bar.

...if you are still not satisfied...

7.  Larger intercooler
8.  Adjust Main fuelling screw...monitor EGT

A rebuilt injector pump & new injectors will also help to increase the power of a Tdi with 100,000 + miles on it!! :roll:

[extreme90]

yep yo right
but,
ive done 3 intercoolers now and all three where like me arse until the smoke screw was altered, off booste was rubbish and so was on boost
that was with the diaphram already at 90 on all

i do the smoke screw at work on the lathe

dan

[Sharpshooter]

Well. I can only say from experiance but.

I have just fitted a full width Allisport intercooler to my 200Tdi Disco.

I also have an ITG Foam air filter.

As per Allisports instructions i have, adjusted the diaphragm so that the largest part of the step is towards the front of the engine. Also shortened the wastegate actuator rod approx 5mm.

I havnt adjusted the fuel at all. Im getting loads more performance and using less fuel.

On monday i had a car transporter trailer with an RRC on it in tow. Now thats about 6 tonnes.

I was pulling up hills in 5th and 4th no probs. And the fuel economy was good too.

I can only tell you what i have experienced, but that is what has worked for me.

[NIVAD]

I also sometimes struggle towing with my 300tdi auto.

But as said i cleaned my intercooler out and i always like to put wynes injector cleaner in the fuel and its inproved mine a bit.

Like the sound of the intercoolers but fitting winch soon.

Got to say though best tow vehicle ive ever had..

[Budgie]

yep yo right
but,
ive done 3 intercoolers now and all three where like me arse until the smoke screw was altered, off booste was rubbish and so was on boost
that was with the diaphram already at 90 on all

i do the smoke screw at work on the lathe

dan

If you mean 90 degrees Dan then on large intercoolers that's too little. The diaphram needs to be turned at least 120 degrees from it's standard setting to allow enough fuel in.
With a standard intercooler I'd turn the diaphram 90 degrees max from the standard setting, after that then your're just wasting fuel.  

[extreme90]

yer, the owners didnt want more as per instructions  :?
dont ask why i honestly dont no, it wouldnt really effect fuel that much as they were concerned about, as your still doing the same speed just at a diff throttle position ( i.e less)
you only drink it when the foot is down
my pumps at around 130 ish :twisted:

on another hand on the towing wise, ive just thought allisport do a thicker high flow std size intercooler dont they  :?
that would help out, but its still going to be running warm as itll need fueling turning up

dan

[Porny]

If you mean 90 degrees Dan then on large intercoolers that's too little. The diaphram needs to be turned at least 120 degrees from it's standard setting to allow enough fuel in.
With a standard intercooler I'd turn the diaphram 90 degrees max from the standard setting, after that then your're just wasting fuel.  

But what's standard??
I've tweaked Tdi's that have had the diaphragm set to min point - from new, and I've seen others when the diaphragm is nearly at max.

The other thing is the dot on top of the metal plate - if the diaphragm has ever been replaced, then the chances are the dot is no longer in the correct place - no two cars are the same... so what works on one, might not work on another.

My 90 runs with the diaphragm set to its max point, without any problem... the star wheel is also tweaked - again without excessive black smoke.

What you need to do it get an understanding of what does what, and then try each modification until you get the desired results.

And if you start turning up overall fuelling then you really want to measure EGT or you will cause damage.


But... the one thing everyone seems to miss is the most important point!!!

Make sure everything is working correctly before you even think about doing any modifications/tuning!!!


I.e:

Check engine and FIP timing is correct - retarded cam timing makes quite a difference!! - you could also advance the FIP slightly.

Check that the fuel pin that operates on the diaphragm is actually moving and not seized!

Check that the throttle cable is correctly adjusted.

Check that you making 1.0bar boost pressure

Check that the lift pump is working correctly

Check the valve clearances - again can make quite a difference

Check that the fuel filter and air filter are clean

Check that the intercooler is clean

Check for splits/leaks in any of the intercooler hoses

Only when you know that everything is correct, and thus the engine is making its (standard) full potential should you start trying to get more.



Have you got EGR fitted, or a CAT in the downpipe?

As mentioned, having the injectors (at least) overhauled/tested/clean will usually make a difference on a high mileage car.




Ian

[chaosego]

i am thinking of getting a cat and mid box replacement pipes will this help power on a standard auto 300 tdi cheers glyn

[Range Rover Blues]

I'd be interested in a definite answer to that, a bloke was selling a S/S system on fleabay with no boxs whatsoever in it and reconed on about 8BHP extra.

But which boxes can you get rid of legally and which are going to make it wake the dead?

When the TDi goes back together next week it's got a new full width intercooler and the inlet pipes and plenum are as clean as they can be.  I know it's been tweaked a bit before so I'll be interested to see how it goes, but most of all I'd like it to be more economical.

[ross501]

i have taken the middle box out and its made quite a difference in power can i take the front box out aswel

[Budgie]

If by the "front box" you mean the cat on the down pipe then it depends on the age of the vehicle and the MOT station you take it too.
I think that 95-96 TDi Discos can have their cats removed as there is no requirement for them to be fitted at that age. But, if your MOT man knows that it was fitted with a cat from the factory then he may fail it for not having one.  

[Horness]

I've been running my 1998 TDi disco cat-less (with a defender downpipe, so no flexy bit to rot) for 4 years now, and it's gone through every MoT.

Next Friday it's off to Allisport for a full width intercooler, bigger rad and replacement header tank. Oh, and some tweaking.  :twisted:

Horness

[Budgie]

Put a Defender down pipe on mine last week and I took the cat off about 4 years ago myself with no problems at MOT but I was just warning in case you get a "jobsworth".  :D