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Max long term boost for 300Tdi

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I know that it's been played before, but technology moves forward, and opinioins change, so what are the views for max turbo boost for 300Tdi for long term life? I know what LR recommend, but we've often shown them to be unreiable.or super conservative.

Mike

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In the Subsea/marine industry you'd conduct a FMECA Failure Mode and Effect Criticality Analysis. Which in short is a putting down on paper a list of your system components and variables which then can be logically rated allowing you to work out what the possible consequences of a worst case failure are, but is also used to check the effect of changes in a system can result in...

To me this logical approach would be the only way to accurately answer such a question. you'd also have to include a consideration for the millage and "duty" the engine has had, a rather important factor.

With a bit of thinking you can probably come up with a list of "tuning" values for your engine that if set will give a certain time based response i.e life time prediction.

Or you just do it and see what happens....

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Or: 'advice is what we ask for when we already know the answer but wish we didn't'.

Some people leave it alone, others completely deactivate the wastegate, and 'it still works'.

Added to toy rovers comments, I would add Intercooling.

you get into high EGR temps, which you can monitor. The factory sets it up in such a way that it never gets in danger of high EGR temps, if you monitor EGR, you can work around that.

Problem is that the higher the boost, the higher the air temp going into the intercooler/engine, and it gets very ineffective very soon.

Allard used to specifically state that they only work on intercooling and fueling, and leave the turbo alone, as higher boost puts more thermal stress on the whole engine.

They do have a stage 3 set now, which includes a new turbo:

This system is as for the Phase 2 conversion, but includes in addition an uprated turbocharger and a boost control valve to allow maximum boost to be raised to 1.25 bar and to match the higher airflow of the improved intercooler system. The normal 16-row intercooler can be replaced by an even larger upto 24-row intercooler. Power 110 bhp (standard) up to 143 bhp (Phase 3) Torque 195 lb.ft (standard) up to 257 lb.ft

Presumably, using the standard turbo, upping the boost isn't giving the results you expect.

Judging from what allard is doing, I'd say leave it.

Daan

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This ^^^^

I was trying to write this, but Daan has summed it up.

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EGT, not EGR, Big difference ;)

Boost is not something evil that will destroy your engine in no time at all when raised. It's just one of the ingredients to be able to make more power. Intercooling only goes so far. More boost in combination with an efficient intercooler lets you burn more fuel cleanly and safely (ie safe EGT) thus more power. It just has to be tuned properly, than it's all just fine and dandy. As long as it's a proper engine to start with, not a 2.5TD for instance. Tdi should be fine being a direct injected engine that has a stronger head than an IDI engine.

Gturbo Diesel Performance builds turbo's for, among others, Cruisers and Patrols. There are plenty of them that run up to 30psi safely on a standard engine, some even more. He supplied a turbo to some Indonesians running a D4D engine (1KD-FTV) that now puts out 400hp/760nm at the crank at 40psi. They run it rich at 15:1 AFR.

Have a look here: https://www.facebook.com/pages/Gturbo-Diesel-Performance/490891624305172

Even the old 1HZ that lots of people claim can't handle much boost can be fed more than 14psi, IF you keep AFR low, like in the 20's:1. I don't mind at all that my 3B boosts up to 20psi intercooled. Keeps AFR up and EGT down at higher rpm, As it doesn't has a boost compensator it does smoke like an old steamliner when you stomp it at low rpm.

Like I said, boost is not an issue, it's the combination of boost, fuel and timing that can make or break an engine. More boost lowers EGT which is fine, you might get a bit more hp if it was running a bit rich. More fuel raises EGT which in turn can be brought down by a more efficient IC and/or more boost.

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Keep in mind the stock boost diaphragm will bottom out and stop adding more fuel at some point. I know the 200TDI does this around 13 psi. I've no idea what the 300TDI does. In any case, more boost without more fuel does not do much useful, so this would need to be addressed.

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So,just assuming for a moment the top end can handle whatever is thrown at it, does anyone have an idea what the bottom end can handle?

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Hi, Guys,

Many thanks for your thoughts on boost, fuelling and intercooling, but as Cackshifter asks, "... what about the bottom end?" This was originally the area of my concern, since higher boost presures increase stresses throughout the engine, so does anybody have experience or views about the effects of higher boost pressures on cylinder head gaskets, pistons, crankshafts, etc?

I already have boost and EGT gauges, the latter mounted dead centre in the dash, where the fuel gauge was, since the EGT varies far faster than the fuel level, and is certainly more important. The fuel gauge is mounted in a MUD dash top panel.

Mike

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IIRC, stock Disco 300Tdi's ran a higher boost pressure than Defenders - despite being essentially the same Engine / Intercooler. I don't know if the fueling was set differently (need to ask a grown-up). The figures I have in my head - which could easily be wrong are 13psi for Defenders and 21psi for Discos.

That being the case, I would imagine that the Disco figure will still result in an acceptable MTBF (Mean Time Between Failures).

I was told the reason was that Defenders were mostly bought by companies - and you don't want your staff 'ragging' your truck up the motorway whereas Discos, mostly by the public who would be disappointed if they couldn't!

This is definitely implemented on Disco Td5's where the ECU controls the waste-gate opening pressure (Waste Gate Modulator) so, if it decides that the EGT is OK, it will allow a higher boost pressure. On Defenders it's just set to the bottom end and they have different fuel maps which further increases the difference!

When I bought my Td5 Defender - I thought it was broken! Having only experienced Td5 Disco performance. The main dealer explained why - and that it was actually pretty good as they go! A different Map from Bell Auto Services fixed that!

Si

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Years ago I worked in the truck industry. The same engine might have had a 160bhp pleasure boat rating, 120bhp truck rating, 105bhp PSV rating, and 90bhp fishing boat rating, just with different fuel pump settings. I think Defenders are at the fishing boat end,the engines last really well in terms of wear (ie durable rather than reliable). If you up the rating, it has to have a shortening effect on overall life, though maybe not as bad as it might seem as the full rating probably isn't used most of the time, and not from cold. The trend back then was to cut the revs and up the boost - more economy. I think there may be other things one could do, eg as most bearing wear occurs during the latter part of its life, change the bearing shells early as a precautionary measure rather than as a result of trouble, use better oil etc

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Sorry to hijack but just out of interest what kind of EGT temperature is deemed detrimental?

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I'm surprised that no-one has responded to your query, but there's already quite a number of threads on the forum that discuss EGT. I've been given to understand that 725 - 750 Deg C is about the limit on 200/300Tdis. I limit my EGT to 1250 Deg F, which is ~677Deg C, which, I hope, gives me a measure of safety. I don't know if the temperature limit is due to piston, valve or turbo metallurgy limitations.

I believe some of the forum members do run 300Tdi's at increased boost, and I was hoping they'd be prepared to share their experience.

I've checked the Disco 2 manual here:

http://workshopmanuals.com/landrover/discovery300tdi/05_engine_tuning_data/information/300_tdi_engine/turbocharger/

for the boost setting, and it is stated to be "0.8 - 1.0 bar", so no comfort to be gained there, in terms of safely increasing boost. Posts #11 and #12 are interesting, but it appears that LR didn’t follow that philosophy with the Disco 2.

RoverLander, in Post #3 and Post #7 you mention timing. Are you referring to valve or FIP timing, and what changes/adjustments increase power/economy?

Mike

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Hi mike.

My 300 do run with increased boost. The engine was bought by a mate of mine and had covered 120k miles. It then went into his rr at the time and we turned it up all it could take incl fueling. It went at 2,2 bar for a month or so of normal usage (NOT drivingstyle) :-) we decided that in the long term perspect we ought to tyrn it back a little and landed somehow on 1,7bar. The engine then moved to a 90 in this tune, and lastly ended in my 90" where it still goes everyday approx 120 km to and from work and is used as a challenge truck now and then. I dont know its exact covered distance anymore, but I have done some 50k km and I reckon my mate did 30k km with it (in enthusiastic style).

It has had a new headgasket due to a waterleak from a watergalleri to the outside and the turbo was changed some 5k km's ago due to a newer one sitting on the bench. In my ownership the engine have "only" been dooing 1,5 bar as I cant get more air through my snorkel etc.. Apparently...

Thats my experiences :-)

Mads

-And no, we didnt fit an egt, young boldness... :-)

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Toenden, Many thanks for sharing your experiences with increased boost pressure.

Mike

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Remember boost is a measure of resistance not flow rate. Simply upping the boost will at 'x' mean you are just wasting energy in heating the intake air and making the setup inefficient.

Think of it this way, a mountain bike tyre could have 30psi of air in it, and so could a 35" Simex Land Rover tyre. The Simex obvious contains vastly more air.

So you could have turbo 'x' boosting 10psi and turbo 'y' boosting at 15psi. But if turbo 'x' is a bigger turbo then it might be flowing a heck of a lot more cfm than turbo 'y'.

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Keep in mind the stock boost diaphragm will bottom out and stop adding more fuel at some point. I know the 200TDI does this around 13 psi. I've no idea what the 300TDI does. In any case, more boost without more fuel does not do much useful, so this would need to be addressed.

isnt that what you take out the little nylon "restrictor" ring for. the diaphragm gets more travel then. at least i can say at 20PSI + boost, you can get it to smoke!!

bottom end wise? i have personally been running a max boost pressure of around 22-24PSI (gauge stops at 20 needle keeps going) and not had an issue with the bottom end, in fact i pulled the pistons just the other week to check the shells due to another isolated issue which turned out to be a stuck exhaust valve and bent pushrod (20-25k miles after rebuild) and they were perfect.

i never really get up to max psi for more than about a second at most. i usually peak it and settle it down to about 18. i dont run an EGT gauge or an engine oil cooler (which i probably should i know i know) but the pistons have no signs of burning or overheating and the bottom end seems to be coping perfectly fine. (on a 200TDi)

to quantify this ideally we need to find someone who uses their engine at full load and full boost for extended periods of time. (if only there were a TDi in a tractor puller)

backing the boost off does dramatically reduce the "kick" you get in your back but at the same time i find myself never daring to use max boost at full load. so maybe if you were to quantify a lower boost value as being safe for extended periods on full load, you would be able to use it more. in effect most probably making it more powerful and torquey than my "too high" boost so cant ever achieve full potential.

being my everyday driver, and fairly freshly rebuilt, i am reluctant to find the limit! hence the need for a TDi powered tractor puller. ideally pulled apart and checked over before and after a days worth of pulling(or after failiure)!

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Remember boost is a measure of resistance not flow rate. Simply upping the boost will at 'x' mean you are just wasting energy in heating the intake air and making the setup inefficient.

Think of it this way, a mountain bike tyre could have 30psi of air in it, and so could a 35" Simex Land Rover tyre. The Simex obvious contains vastly more air.

So you could have turbo 'x' boosting 10psi and turbo 'y' boosting at 15psi. But if turbo 'x' is a bigger turbo then it might be flowing a heck of a lot more cfm than turbo 'y'.

I partially agree and partially disagree with this. yes, more flow is the ideal, but thats only if you cant get enough air into the cylinders at any one time at a higher boost.

the more pressure going in (assuming the value of oxygen in the atmosphere is X) means the more oxgyen going in.

think of it as rather than PSI as XSI (oxgygen per square inch) at 13XSI you will have less oxgyen than at say 20XSI (ignoring the effects of superheating and therefore expanding the air)

so as long as your turbo is big enough to fill the cylinders (of which im sure someone clever has an equasion for)(in fact thinking about it qould be quite simple using displacement and RPM you can work out required CFM) then more pressure will give a benefit AS LONG AS you can cool it back down to a sensible temperature. which is where bigger More efficient intercoolers are required!

the bigger the intercooler the more lag and pressure drop. which is a conversation for anoter day!

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was googling trying to find a max acceptable boost level for my 2.8tgv.

the vehicle is running an uprated intercooler and tweaked pump.

it used to max at 720EGT.

i recently changed the VVT feed from the outlet of the turbo to the back of the manifold so the vanes now change with respect to the pressure at the back of the inlet manifold rather than at the exit of the turbo compressor side.

Massive difference in driveability of the vehicle and EGT are generally down as more air is now going in for any set fuel delivery relative to pressure. (as i understand it)

Also decided to fit a boost gauge at the inlet manifold feed. 1.2-1.4Bar so too much for a tgv head? anyone know how it would fair on a 300tdi head running at 1.2 to 1.4bar? (17-20psi)

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as an aside i left the FIP diaphram pressure feed connected to the turbo outlet so its running slightly advanced of the turbo pressure feed so fuel delivery is not lagging.

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