I'm Curious...

Well I was just laying in the bath earlier and I started thinking about a load of random stuff, anyhow, I got thinking about my 90. I absolutely love my 2.5 N/A, but the fact that they loose so much power on any kind of incline has got me puzzled. Here's the thing: There's four cylinders, each of which are sealed and are well within the compression tollerances. Each piston in each cylinder is working in pretty much exactly the same way as they would in a 200 tdi, without the real blast of air from the turbo of course, so why is it that a 200 tdi doesn't really slow down on hills? Where does my loss of power come from, and where does all that energy go to? It's almost as if it's losing compression, or the bang is just seeping out of the cylinders somewhere!?

All 2.5 N/A's are the same, but whhhhy?

Can't figure!
-Pos

must be just magic....some little pikey nicking your bang

aye probably

That blast of air is a good thing, it pushes ya up the hills

Compression ignition Landy engine .... naturally aspirated ... SUCKS in air into cylinders each of which is a bit over 650 cc swept volume. Maximum air each cylinder can such in is about 650 cc.

On full throttle injects as much fuel as will be burned by 600 cc of air.

Now add TURBO. Turbo BLASTS air in under pressure, in fact turbo can blast in nearly twice as much air as engine could suck. Turbo tells injection pump " Hey fella, heave in more diesel!" and injection pump shoves in more diesel to match the extra mass of air.

More fuel burning in more air in same engine equals more power.

CharlesY

An if yer slap an intercooler on that cools down the air entering the cylinders an so makes it denser so you end up with even more air in there.

GRUNT said:

An if yer slap an intercooler on that cools down the air entering the cylinders an so makes it denser so you end up with even more air in there.

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Sure does!
The man says it like it is.

But even in an old N/A diesel, fitting a simple turbo and shoving in a tad more air WITHOUT a change of injection pump (so no extras diesel) will make the engine more EFFICIENT, especially when it is working on medium to full load.

The extra efficiency comes as a result of two things:
1. the extra air means the effective compression ratio is higher, so ignition and combustion are both better and hotter = good.
2. the extra air means there is a greater mass of even hotter air to expand, so it pushes the piston harder for longer = good.

And just to round it off, if nothing else, the turbo captures waste POWER from the exhaust gases, and uses that power to compress the inlet air, and physically help to blow the pistons down on the induction strokes, saving the engine from wasting the power of power strokes to drag the pistons down. This then has another effect, and that is by always having POSITIVE PRESSURE on the piston crown under load, the jerk on the big end bearings is less, because usually there is positive pressure on THREE strokes (compression - power - exhaust) whereas there is suddenly NEGATIVE pressure on induction strokes as it SUCKS air in. With the turbo blowing hard at say 15 psi, onto the top of a piston of nearly 10 square inches area, that's a down-shove of about 150 pounds thrust, over ten stones!

It makes a difference. There's a lot going on inside a simple Landy Diesel!

CharlesY

Wow, thanks for the explanation CharlesY! I'm happy with my N/A, but if I was to fit just a turbo charger on its own, would there be a noticeable difference on hills? The only problem that I have with that is the Insurance. Being 18, the word turbo seems to add a hell of a lot onto the premium. Is it likely to cost a lot more to insure my 2.5 N/A with a turbo block? ie. 2.5 Turbo?

Cheers
-Pos

that all depends on the car. i had a nova TD and it performed better than the nova gti , in every aspect . the main difference was the ins was cheaper fer the TD

mmm. Well I've just been having a quick look on the net for turbo chargers (out of interest), anybody know of any good cheap suppliers?

Car Turbos | Turbochargers | Garrett Turbo Charger | UK | GReenwich

Garrett T23 is the one you want, might need some fudging/bodging/fettling wiv #1 universal tool to get the oil line through to it though...

slob said:

i had a nova

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FECKIN ELL.......

Lord Slob used ter be a CHAV!

Hi

yeh i am young i got 300tdi and the cheapest place i found was bell just over a grand fully comp

Treworgey 90 said:

FECKIN ELL.......

Lord Slob used ter be a CHAV!

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it wur either a td nova or a metro

pos said:

Well I was just laying in the bath earlier and I started thinking about a load of random stuff, anyhow, I got thinking about my 90. I absolutely love my 2.5 N/A, but the fact that they loose so much power on any kind of incline has got me puzzled. Here's the thing: There's four cylinders, each of which are sealed and are well within the compression tollerances. Each piston in each cylinder is working in pretty much exactly the same way as they would in a 200 tdi, without the real blast of air from the turbo of course, so why is it that a 200 tdi doesn't really slow down on hills? Where does my loss of power come from, and where does all that energy go to? It's almost as if it's losing compression, or the bang is just seeping out of the cylinders somewhere!?

All 2.5 N/A's are the same, but whhhhy?

Can't figure!
-Pos

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These engines also have a seperate combustion chamber in the head, the injector and glow plug are in a little sort of snail shaped chamber, it starts to burn here, blasts through a hole into the cylinder and burns completely. These engines works very well at low speeds, however at higher speeds there are pumping losses because it has to suck and blow through a little hole.

pos said:

mmm. Well I've just been having a quick look on the net for turbo chargers (out of interest), anybody know of any good cheap suppliers?

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You will need the turbo manifold as well.

slob said:

it wur either a td nova or a metro

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dunt start mekin eggscuses


bet yer ad a 6" diameter eggsaust pipe an all

fooking dint, nevva barried a car in me life. i prefered the pile of dhit look on a car that could shift.i.e vauxhall shove-it with no matching body panels and a fiat twin cam lump. looked like a reet mot failure but wur mechanically sound and tyre melting fast

Mah furst un worra Mk I Astra 1300GL - **** brown metallic, went like stink by the time ahd finished wiff the porting job an weber carbs

pos said:

mmm. Well I've just been having a quick look on the net for turbo chargers (out of interest), anybody know of any good cheap suppliers?

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are you mad pos, why would you do this, for starters it would probably be cheaper to put a TDI in there (which is not only turbocharged already, but also direct injection and has an intercooler, as well as being a stronger block), and also you would effectively be creating yourself a TD 19J and why would you do that???!