any tips for boosting 2.5TD performance?

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J

John de Wit

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Just have a "new" Turner Engeneering supplied 2.5TD engine in my 1989 Land Rover ninety. It runs smooth :) but as soon as going uphill...:(.
What is the best way of making it a bit more powerful for motorway use, except for switching to a 200TDi (my car runs in Switzerland and the 200TDi was never homologised there)
 
No idea...but I assume its a bog standard one? The main gearbox is a 5speed with the reverse left next to 1st.
 
There isn't much you can do to improve a td. You're lucky it's a good one imagine what a tired old thing with smoke coming out of every orifice would be like.
 
K&N filter?
Hiclone is trashed in the comments here, which I support
No experience with adding an intercooler? More air and more fuel=more power? Or is the TD just :mad:
 
hi
yeah if you can get ur hands on a 200tdi turbo its fits the original manifold but has a biger intake vane so more air and if u fit a intercooler and also turn up the pump on the block side down half way i will put up a pic but dnt hav 1 now dis shud add a bout 20-30 hp on a very gud engine
 
landyman110 said:
hi
yeah if you can get ur hands on a 200tdi turbo its fits the original manifold but has a biger intake vane so more air and if u fit a intercooler and also turn up the pump on the block side down half way i will put up a pic but dnt hav 1 now dis shud add a bout 20-30 hp on a very gud engine
Click to expand...

that's a grand way of killing a TD
 
landyman110 said:
no no its not my m8 has it done to his 110 wit the head ported and polished and boarded out to 2.6 so iv seen it and it works http://www.landyzone.co.uk/lz/images/smilies/cool.gif
Click to expand...

Yes but that's not a fair argument. He's re-bored the engine and therefore increased the volume of each cylinder. He would NEED to increase the fuel and the boost in order for it to run just as well as the standard 19J because he's lowered the compression ratio for the standard amount of fuel and air that is present in the cylinder, without turning up the fuel or adjusting the boost. He's effectively not increased the boost or the fuelling to suit the original engine, but increased the boost and the fuelling to meet the minimum requirements of the re-bored engine, which wont go much better anyway. You've got to remember that these really are 'old-hat' engines. They rely on a pre-combustion chamber that quite literally dribbles collated fuel into the cylinder which is also partially atomised when it is drawn into the cylinder on the downward stroke. In theory, every batch of fuel that is drawn and dribbled into the cylinder per air intake stroke will be slightly different to the next because the fine diesel spray from the injector is interrupted by the nodules in the pre-combustion chamber. This is one of the reasons why 12J's (2.5 N/A) and your 19J are poor on hills too. Sure the turbo can cram enough air into the cylinder, but the head and injector combination is not capable of delivering the right 'pattern' of fuel, nor in high enough a quantity to give it any extra oomph. If you turn your fuel up you'll probably find that your engine just starts to produce a lot of black smoke and you'll loose some of the little efficiency it already has. Giving it more boost will put more stress on the engine and you'll eventually experience cracked pistons, worn bearings and oval shaped bores that are worn beyond repair.

Leave it be, keep it ell serviced and treat it like a tractor. That is (in theory) what it is. The 200TDi and later, were totally re-thought with regards to the fuel delivery and the strength of the engine.

-Pos
 
The Mad Hat Man said:
Hang on Pos. If he has bored the engine, he will have increased thesweptolume and inreased the compression ratio, not decreased it.
Click to expand...

On the whole yes, but if he had left the fuel pump and the turbo boost exactly as they were when it was a 2.5, wouldn't he have a larger space for the same amount of fuel and air, thus reducing the overall compression for the given (standard) ammount of fuel injected? If he'd halved the diameter of the bores but kept the fuelling and the boost the same, that should be an even higher rate of compression for the given volume of fuel injected and air drawn / pushed in. Does it not work like that? Surely a higher capacity engine needs more air and more fuel for it to run efficiently (not underpowered).

-Pos
 
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i think yu is confused, POS.
if the swept volume is increased and the unswept volume remains the same, then the compression ratio is increased. It has nothing to do with fuelling. The engine will be drawing in a larger volume of air and compressing it into the same volume. I accept that the injectors may only inject the same volume of FUEL for a larger volume of air, but that means that the fuel mix will be weaker - nothing to do with compression ratio.
 
The Mad Hat Man said:
i think yu is confused, POS.
if the swept volume is increased and the unswept volume remains the same, then the compression ratio is increased. It has nothing to do with fuelling. The engine will be drawing in a larger volume of air and compressing it into the same volume. I accept that the injectors may only inject the same volume of FUEL for a larger volume of air, but that means that the fuel mix will be weaker - nothing to do with compression ratio.
Click to expand...

I know what I'm trying to say! :D You've pretty much cracked it with regards to the fuelling though. I still cant get my head around how the compression has been increased though :eek: Sure the engine will draw in more air, and the ported head will make the air flow in and the exhaust gas flow out more efficient, but all he has done is simply widen the cylinders and fit bigger pistons. When you say the compression ratio has been increased, are you referring to the higher volume of air that is being compressed in a single stroke? I was thinking more along the lines of the profile of the piston crowns but I see where I was wrong now. So the only way that you can increase compression would be to increase the size of the bores, move the piston crown closer to the head (extend con rods), flatten off any dimples in the valves or make the piston crown totally flat?

-Pos
 
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compression ratio is simple maths - swept volume:compressed volume.....
for example, lets assume that it is a one cylinder engine and it is a 2.5Litre - that means in every inlet stroke it draws in 2.5 Litres of air . Lets also assume the compressed volume is 100cc. that engine will have a compression ratio of 25:1.
If the engine is bored out so that it has a swept volume of 2.6litres, then the compression ratio is 26:1. that is why peeps overbore engines to get more power.
Additionally to this, and this is where my doozil/turbo knowledge is skimpy, the turbo compresses the incoming air to give an effective higher compression ratio, because the air that is being drawn in is, to some degree already compressed by the turbo. Maybe the turbo can cope with higher volumes of air, maybe not, or maybe it needs to be "turned up" to give the same boost as before - I am not sure.
If the fuel is injected, rather than just drawn in (thru a carb) then the amount injected has to be regulated. If the volume of air being drawn in is increased, then the amount of fuel injected would have to be increased proportionately to keep the air/fuel mix the same as before. I do not know if this is automatic on the 2.5 (unlikely) or not. Later engines with electronic management systems which can check fuel leanness, will adjust to compensate.
Others with a much better knowledge of the fuel injection systems should be able to answer the above.
 
The Mad Hat Man said:
compression ratio is simple maths - swept volume:compressed volume.....
for example, lets assume that it is a one cylinder engine and it is a 2.5Litre - that means in every inlet stroke it draws in 2.5 Litres of air . Lets also assume the compressed volume is 100cc. that engine will have a compression ratio of 25:1.
If the engine is bored out so that it has a swept volume of 2.6litres, then the compression ratio is 26:1. that is why peeps overbore engines to get more power.
Additionally to this, and this is where my doozil/turbo knowledge is skimpy, the turbo compresses the incoming air to give an effective higher compression ratio, because the air that is being drawn in is, to some degree already compressed by the turbo. Maybe the turbo can cope with higher volumes of air, maybe not, or maybe it needs to be "turned up" to give the same boost as before - I am not sure.
If the fuel is injected, rather than just drawn in (thru a carb) then the amount injected has to be regulated. If the volume of air being drawn in is increased, then the amount of fuel injected would have to be increased proportionately to keep the air/fuel mix the same as before. I do not know if this is automatic on the 2.5 (unlikely) or not. Later engines with electronic management systems which can check fuel leanness, will adjust to compensate.
Others with a much better knowledge of the fuel injection systems should be able to answer the above.
Click to expand...

Thanks for that :) One last thing! If you re-bore the engine from 2.5 to 2.8 litres, you've increased the physical size of the bore, so wouldn't the compression ratio increase too? I thought you could only increase the CC by increasing the cylinder size, and also, if you increase the cylinder size, the CC is increased no matter what? Wouldn't it effectively become a 28:?

-Pos
 
pos said:
Thanks for that :) One last thing! If you re-bore the engine from 2.5 to 2.8 litres, you've increased the physical size of the bore, so wouldn't the compression ratio increase too?-Pos
Click to expand...
yes - that is what i said

pos said:
I thought you could only increase the CC by increasing the cylinder size, and also, if you increase the cylinder size, the CC is increased no matter what? -Pos
Click to expand...
if by CC you mean Cubic Centimetres then yes it must.


Wouldn't it effectively become a 28:? - only in my example.
you can also increase the compression by reducing the combustion volume - it used to be the case of skimming the head and thereby reducing combustion volume, but that doesnt work if the combustion volume is in the piston and the head is flat.

:confused: yet?:D
 
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