hi want to tune my 300tdi engine further than just a tweak or two to the pump, may be better turbo possibly off a junk yard motor. have propane injection ready to go on want to get around 180-200hp if poss may have to do something to the head better cooling, better head fixings ,bit of gas flowing

I too would like to know a good BBS for tuning a 300tdi.

thanks
Ed

hi want to tune my 300tdi engine further than just a tweak or two to the pump, may be better turbo possibly off a junk yard motor. have propane injection ready to go on want to get around 180-200hp if poss may have to do something to the head better cooling, better head fixings ,bit of gas flowing

1. Take it out and sell it to someone who will put it to good use

2. Spend the $$ on a good V8

Turn the full fuel screw up until you melt a piston and back it off a smidge :D

Seriously a VE can be hard to setup and someone with experience is worth the bucks. Matt Browne or Jim Pendleton could set it up for you and it would be worth a few hours worth of their time.

Couple of classic links...

http://dodgeram.org/tech/dsl/more_power/Power_ve.htm

http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html

Do a search for "Tdi tuning" or check the LR4x4.com BB out,
in the tech archive there should be the step-bystep guide for DIY.

But...180/200 HP?
I'm no engineer but sounds too much :shaking:

You'll need a new manifold for a new turbo. Just head to Brazil and get yourself the VGT turbo and manifold off the 2.8 they use there.
Stay away from the gas.

I did a butt load of research on Propane injection for the race. The general concensus is that it would work very well on the 300Tdi. But, you have to have a mild dose, too much and all sorts of issues can come up. Not to mention that you are probably close to $2000 all said and done with a good system, a DOT tank, and shipping. Maybe a little less if you bargain hunt but even at cost I was over $1000. Thats a lot for 40HP. My guess is that 175HP is possible, but with reservations. Then your over the torque limitations of the r380 anyway.

Bottom line for me was that the best thing about these motors is the reliability. They just never stop. If you F with it enough to take that away, you will really just end up with a slow iffy motor. It would crawl really well though. Man does this thing crawl well...

the injection pump has two adjustments for fueling. there is a constant fuel pin in the center of the pump. there are 4 bolts that hold this on place on top. there is a spring the can change fuel under acceleration. This is changed by tuning a ring below the metering needle.

I had problems with alot of black smoke with my 300tdi until I tuned the pump.

I highly recommend that get a EGT gauge so you can monitor the exhuast temp.


Ed

the injection pump has two adjustments for fueling. there is a constant fuel pin in the center of the pump. there are 4 bolts that hold this on place on top. there is a spring the can change fuel under acceleration. This is changed by tuning a ring below the metering needle.

I had problems with alot of black smoke with my 300tdi until I tuned the pump.

I highly recommend that get a EGT gauge so you can monitor the exhuast temp.


Ed

In your opinion, when is exaust temp too high?

Hi

I try to never go over 1000 degrees. if it gets close I slow down.

in normal operating EGT is 650

thanks
Ed

I try to never go over 1000 degrees. if it gets close I slow down.

1000 F is crazy low. Where is your sensor located?

1300 F is a more reasonable limit assuming the gauge is pre-turbo.

with the propane kit i got from allisport you can set it to come in at what boost pressure you want ,so you only get the amount you want,works well and you dont need it all the time.we use 300 tdis over here due to the amount of mud and water we have to contend with in comps, we also run mostly autos which you can get sorted by ashcroft to use half tdi auto and half p38 v8 auto.keep it coming all good stuff cheers gary

Those Ashcroft diesel trannys are pretty sweet. Nicest autobox I've ever hung on a 300.

I consider 1300 - 1350 in small doses for a pre turbo EGT. Can sustain 1150 1200 for pretty long stretches. Not sure what the experts will say but I'm surviving with it so far.

Never messed with the propane. Have a hard enough time getting my tailgate to stay shut already.

My temp sensor goes in at the turbo. It replaces the blanking plate on the turbo.

where does your sensor go. after or before turbo?

Ed

.

Bottom line for me was that the best thing about these motors is the reliability. They just never stop. If you F with it enough to take that away, you will really just end up with a slow iffy motor. It would crawl really well though. Man does this thing crawl well...


:laughing: yeah thats what i was hoping....mine spun a crank to conrod bearing at 230k kms and when it was in the shop there were 2 other 300tdi's getting full rebuilds, one melted the pistons the other had a casting flaw in the block letting coolant leak...... typical LR quality control :shaking:

at the end of the day 2.5 lts is to small a capacity tobe pushing the mass of these trucks+ and then to tweak them is playing with fire....

but what i found out about the 300tdi is:

#1 the cooling system is marginal at best when 100% fully functional. this needs to be addressed.

#2 the temp gauge has a large buffer in it. it will read normal from 89c to 98c...

#3 intercooling is undersized to say the least.

#4 defender engine bays hold the hot air and heat in, look at venting to let this air out.

Serg

:laughing: yeah thats what i was
#2 the temp gauge has a large buffer in it. it will read normal from 89c to 98c...


This only seems to be the gauges that came in the 300TDI truck, BTW. The gauges pre-300TDI do not do this. So a quick and cheap fix is to grab a gauge from an older truck. The senders are the same range, I believe....

FWIW I'd say beyond a quick twiddle of the FP don't fuck with it, you guys live in the land of cheap big V8's and cheap gas, if you want extra BHP then just buy something that can do it out of the box without stress.

You tune a TDi you lose reliability and fuel economy which are the only two reasons to have one in the first place. Except they're not that reliable. :p

Might I touch wood now John
:flipoff2:


Hey as per Dougal post,
some clever guys already switched to a VGT,
all bolt-on bits from the International parts list...

I'm in touch for a group buy and there's a 15% discount for a 5 kits order...it could be a start...
1245GBP is retail price though! :(

FWIW I'd say beyond a quick twiddle of the FP don't fuck with it, you guys live in the land of cheap big V8's and cheap gas

I used to think that until I went there. Petrol is cheap - but everything three or four times further away!

Some diesel tuning ideas here (http://www.allardturbosport.co.uk/index.php?page=Land-Rover)

This only seems to be the gauges that came in the 300TDI truck, BTW. The gauges pre-300TDI do not do this. So a quick and cheap fix is to grab a gauge from an older truck. The senders are the same range, I believe....

Are they the same thread JB ?

Anyway, a VDO mechanical gauge is a bolt in, the sender is 1/8"-27 NPTF for a 300Tdi and stock VDO thermowell.

1000 F is crazy low. Where is your sensor located?

1300 F is a more reasonable limit assuming the gauge is pre-turbo.

Yep, I've seen 1150F pre turbo on bog stock fuelling. (I had to get my temp charts out, wish you blokes would talk in SI )

I use 1330 F pre turbo and it's been running at that for a few years know. Contrary to what fridge reckons, MPG's haven't deteriorated much at all.

The easiest, step by step instructions to 300Tdi pump adjusting is here http://www.aulro.com/afvb/attachments/technical-chatter/326d1152411367-how-get-more-hp-out-tdi-300-thermoguard-20tdi-20tuning-20rev.2.pdf



Serg, what radiator did you end up using and did you end up venting the bonnet ?

You'll need a new manifold for a new turbo. Just head to Brazil and get yourself the VGT turbo and manifold off the 2.8 they use there.
Stay away from the gas.

or a 200Tdi exhaust manifold and a suitably setup GT28R. (If I knew how to set one up :shaking: )

Bruce Davis used to use a T25 turbine housing with the T250 and different turbine and compressor wheels on a 200Tdi manifold.
It actually bolted up to the stock inlet ducting and IC piping with little modification and a custom cast dump pipe to meet up to the stock exhaust.

http://usera.imagecave.com/tdi-rick/Ricks%20Pics%20067.jpg

I see several options.

1. Do the standard tweaks to the pump, make sure the turbo is boosting correctly and slap a huge intercooler on it. That should see in the region of a 35% gain in hp/torque ~150hp/260lb ft

2. If you want more slap a nitrous oxide kit on and run as big a shot as you can fuel for and that you are brave enough to do

3. Fit a different diesel engine. The TD5 is cheap in the UK and can fairly easily see over 200hp. Or look for a US grown diesel such as a GM Duramax V8 or somthing.

4. Go for a petrol/gas V8. Even a midly tweaked RV8 of 4.0 litres+ will out HP any TDI no matter what you've done to it. Not too mention the good supply of Chevy or Ford small blocks that are even more capable.

You can get gas flowed/ported heads for the Tdi and I've seen custom water cooled turbo setups as well. 180bhp still seems a challenge though.

I love the TDI's (on my 3rd after selling one and blowing another), but they do have quite low limitations in the HP department.

You can make 200 hp with the addition of a better turbo and the other mods. There is a guy around these parts who is easily up in that range on a 200TDI without propane or NOS.

With all this talk of tuning and HP numbers I would have to say I call bullshit on anything that doesn't have a dyno sheet to go with it.

Numbers from the websites of companies selling tuning bits are not admissible.

With all this talk of tuning and HP numbers I would have to say I call bullshit on anything that doesn't have a dyno sheet to go with it.

Numbers from the websites of companies selling tuning bits are not admissible.


You can do a quick check on their numbers.
With no boost you're only going to get about 70Nm for every litre, so for a 2.5 that's 175Nm.
15psi boost with no intercooler and you can get 60% more (280Nm).
15psi boost with a good intercooler and you can get 80% more (315Nm)
20psi with a good intercooler and you can get double (350Nm).

200hp at 4000rpm requries 350Nm with an air consumption of approx 22 lb/min.
That's a 51mm T25 turbo with it's balls to the wall pumping 21psi boost and the fuel pump delivering about 80cc/1000 shots.

So it's doable, but you'd be upgrading the turbo, intercooler and probably radiator too.
If you need to run more air to keep the EGT's under control then you're looking at a T28 sized turbo (60mm compressor wheel) and even more boost.

Yep, I've seen 1150F pre turbo on bog stock fuelling. (I had to get my temp charts out, wish you blokes would talk in SI )

I use 1330 F pre turbo and it's been running at that for a few years know. Contrary to what fridge reckons, MPG's haven't deteriorated much at all.

The easiest, step by step instructions to 300Tdi pump adjusting is here http://www.aulro.com/afvb/attachments/technical-chatter/326d1152411367-how-get-more-hp-out-tdi-300-thermoguard-20tdi-20tuning-20rev.2.pdf



Serg, what radiator did you end up using and did you end up venting the bonnet ?


i had a new core fitted when the head was replaced before the new engine... i just got sick of spending more and more money. i eneded up finding a lower thermostat that seems to work well so now i just drive with one eye on the temp gauge(vdo) and the other on the egt gauge(vdo)....

i still need to do the wipple(?) test on the sides of the gaurds where the intakes are

Serg

You can make 200 hp with the addition of a better turbo and the other mods. There is a guy around these parts who is easily up in that range on a 200TDI without propane or NOS.

Have you got any more info on their setup?

Not exactly, I will try and remember to ask. It is some sort of VNT turbo and I'm not sure his boost levels, but at least 20 psi. Full width intercooler, possible Allisport and the fueling adjusted as needed to suit.

Don't forget the dyno figures :p

Don't forget the dyno figures :p

When he drives up hills in 3rd high and you are needing 2nd low, you tend not to ask for proof.....

When he drives up hills in 3rd high and you are needing 2nd low, you tend not to ask for proof.....
I guess that proves it then, 200 on the nose.

I guess that proves it then, 200 on the nose.

Yes, we understand you don't believe it is possible.

Do you believe that someone can get 200 WHEEL horsepower from a 1.9 liter VW diesel with the same style of injection system? And another 50 easy with NOS. There are many doing that with dyno sheets.... It is a heck of a lot easier with another 500 ml of displacement.

In one of my previous incarnations I used to design armoured vehicles. While trying to spec an engine for a new project I asked the manufacturers what horsepower they could give me. The reply was 1000, if you like - but it won't last very long. The normal commercial rated output of that particular engine (Perkins TV8 640) was around 230 hp. IIRC we settled on 450 as a reasonable balance of performance against longevity.

How long do TDI's last at 22+ psi boost?

I guess that proves it then, 200 on the nose.
Well maybe not, but seriously it is a 2.5 litre turbo motor and 200hp really isn't that much. With the right parts I can see it being possible, just not cheap.

Remember the guys in the US get 500, 600 and over 800bhp from their 6 and 8 cylinder diesels. Often well exceeding 100bhp/litre specific output. To get a Tdi to 200bhp we only need 80bhp/litre.

Also a TD5 with the same 2.5 litres of displacement will make around 220bhp with just bolt ons and tuning, so I its probably not out of the question that a Tdi would be around 10% behind.

Yes, we understand you don't believe it is possible.

Do you believe that someone can get 200 WHEEL horsepower from a 1.9 liter VW diesel with the same style of injection system? And another 50 easy with NOS. There are many doing that with dyno sheets.... It is a heck of a lot easier with another 500 ml of displacement.


I have seen plenty of 1.9TDIs with that kind of horsepower but no 1.9 IDIs or 1.9 mechanical TDIs. TDIs have a VP44 that has computer controlled advance and injection, not to mention computer controlled variable geometry turbo. I'm not saying it's not possible but let's be fair. I am building an MTDI for my 69 Westy project, hoping for about 100 hp and would actually like to try and LR 300TDI pump on it.

I'm not saying it's not possible, I'm saying that if you're going to talk about tuning options then backing HP claims up with some sort of facts would be nice.

I'm sure you could get 500bhp from a 300TDi if you really wanted but the chances are it'd be undriveable and last about as long as a hamster in a washing machine.

I stand by my original post on the subject - in pure terms of cash Vs HP the whole thing starts to look pointless shortly after the mods you can do yourself for no money. The same is broadly true for the Rover V8 as well.

Modern engines make much better numbers, are far more reliable and because of that are available for very little money. Even stuff like BMW and Lexus V8's go for less than £500 because there isn't the 2nd hand demand for them.

There are racers here who spend £10k plus on tuning Land Rover engines, and it's just the dumbest thing ever when you could have something like an LS with your choice of gearbox and transfer box sat in the workshop with a nice pink bow round it for less money.

Except, you get the power and can keep the economy at the same time. You can't do that with a V8.

Plus diesels are so much nicer to drive. Example. I have a Golf TDI that is running say 125 hp. A friend has a GTI VR6 of the same age. I think they are 175 hp. I've driven them back to back and both of us would swear the TDI is faster. It certainly is not faster, but the power curve of the diesel is so much better from the driver's perspective. I have problems driving gassers now, they all feel dead.

Except, you get the power and can keep the economy at the same time. You can't do that with a V8.
Not sure what you're referring to there but this isn't a V8-vs-TD internet dick waggling competition so let's not go into one.

I was looking at JE Engineering's website earlier and they claim to get a whopping 132bhp out of the 300TDi for a mere £1000.

I have problems driving gassers now, they all feel dead.

I suspect that what you are feeling is the difference between a turbo and NA motor. It would be more fair to compare the Golf Tdi to a Golf 1.8T in terms of power delivery and torque curve. The VR6 is not a torquey motor the same way that a boosted 4cyl (diesel OR gas) will be.

I do completely agree with what you're saying, though. After driving something with a turbo, anything NA feels dead. The power delivery is all wrong.

I suspect that what you are feeling is the difference between a turbo and NA motor. It would be more fair to compare the Golf Tdi to a Golf 1.8T in terms of power delivery and torque curve. The VR6 is not a torquey motor the same way that a boosted 4cyl (diesel OR gas) will be.

I do completely agree with what you're saying, though. After driving something with a turbo, anything NA feels dead. The power delivery is all wrong.

It's not just that, diesel turbo's still have a very different power curve to petrol turbos.

I agree though about the feel. A tweaked TDI Landy may not be as quick as a V8 but having all the power at the top of the throttle pedal for that instant whack in the back makes for a bigger grin, even compared to the low end grunty RV8.

I suspect that what you are feeling is the difference between a turbo and NA motor. It would be more fair to compare the Golf Tdi to a Golf 1.8T in terms of power delivery and torque curve. The VR6 is not a torquey motor the same way that a boosted 4cyl (diesel OR gas) will be.

I do completely agree with what you're saying, though. After driving something with a turbo, anything NA feels dead. The power delivery is all wrong.

No defintitely not. Turbo gassers are worse. Go drive a modern diesel, you'll see what I mean.

Well maybe not, but seriously it is a 2.5 litre turbo motor and 200hp really isn't that much. With the right parts I can see it being possible, just not cheap.
.................
Also a TD5 with the same 2.5 litres of displacement will make around 220bhp with just bolt ons and tuning, so I its probably not out of the question that a Tdi would be around 10% behind.

you cannot compare a td5 to a tdi - even though they both are 2.5l turbo diesel engines!
one is a 5 cylinder highly advance (well for a landie) computer controlled high revving diesel, with each injector in essence having its own computer controlled fuel injection pump. The other is a 4 pot heavy slogger with its engine design traced back 50 years!!!!!
thats like comparing an early buick v8 from the 1950s to the latest 4.6rv8 fitted to the last of the rangerovers!

Yes you can make a tdi produce the same sort of power per litre as a modern diesel. You can throw the pistons and crank and cam away for a start. Replace them with completely new lightweight versions made from unobtanium with the crank and cam redesigned for the appropriate valve durations.
then rip the head off and spend more hours than is entirely healthy grinding out every single bit of material you can for the best flow characteristics and fit the biggest valves possible without breaking into an oilway etc.
then scrap the turbo and fit a nice VNT version that matches the capacity and flow characteristics of your new head and cam and compression ratio. How you'd work that out without some really clever equipment and R&D facility i'm not sure.
then ditch the injectors, cos there is no way they will be able to deliver the quantity of fuel required in a short enough duration for this sort of power level.
then replace the fuel injection pump, cos there is no way that will cope with the volumes and pressures either.

once you have all the sorted out, you will get past your 100bhp/tonne mark.
But it aint a 200tdi any longer. and it would have cost you significantly more than a brand new competition ready LS engine/gearbox and a supertanker full of fuel!!!!!!



you cant polish a turd. A tdi is not built for high revving high HP outputs. The internals and valve durations, timing and fuelling just arent right for it. By comparison it is actually a powerful motor per revolution.

A tdi will rev to 4250rpm giving 0.026hp/rev
a td5 will rev to 5250rpm giving 0.025hp/rev
So if you could get a tdi to rev to the same limit as a td5 without it exploding, then it would actually produce more power in theory. and thats without any ECU or hell-ecktrickery.

you cannot compare a td5 to a tdi - even though they both are 2.5l turbo diesel engines!
one is a 5 cylinder highly advance (well for a landie) computer controlled high revving diesel, with each injector in essence having its own computer controlled fuel injection pump.



By comparison it is actually a powerful motor per revolution.

A tdi will rev to 4250rpm giving 0.026hp/rev
a td5 will rev to 5250rpm giving 0.025hp/rev
So if you could get a tdi to rev to the same limit as a td5 without it exploding, then it would actually produce more power in theory. and thats without any ECU or hell-ecktrickery.

So first you say you CAN'T compare them, then you DO compare them and admit that the Tdi is actually a pretty good motor. What is it that you really believe?

you cannot compare a td5 to a tdi - even though they both are 2.5l turbo diesel engines!
one is a 5 cylinder highly advance (well for a landie) computer controlled high revving diesel, with each injector in essence having its own computer controlled fuel injection pump. The other is a 4 pot heavy slogger with its engine design traced back 50 years!!!!!
thats like comparing an early buick v8 from the 1950s to the latest 4.6rv8 fitted to the last of the rangerovers!

Yes you can make a tdi produce the same sort of power per litre as a modern diesel. You can throw the pistons and crank and cam away for a start. Replace them with completely new lightweight versions made from unobtanium with the crank and cam redesigned for the appropriate valve durations.
then rip the head off and spend more hours than is entirely healthy grinding out every single bit of material you can for the best flow characteristics and fit the biggest valves possible without breaking into an oilway etc.
then scrap the turbo and fit a nice VNT version that matches the capacity and flow characteristics of your new head and cam and compression ratio. How you'd work that out without some really clever equipment and R&D facility i'm not sure.
then ditch the injectors, cos there is no way they will be able to deliver the quantity of fuel required in a short enough duration for this sort of power level.
then replace the fuel injection pump, cos there is no way that will cope with the volumes and pressures either.

once you have all the sorted out, you will get past your 100bhp/tonne mark.
But it aint a 200tdi any longer. and it would have cost you significantly more than a brand new competition ready LS engine/gearbox and a supertanker full of fuel!!!!!!



you cant polish a turd. A tdi is not built for high revving high HP outputs. The internals and valve durations, timing and fuelling just arent right for it. By comparison it is actually a powerful motor per revolution.

A tdi will rev to 4250rpm giving 0.026hp/rev
a td5 will rev to 5250rpm giving 0.025hp/rev
So if you could get a tdi to rev to the same limit as a td5 without it exploding, then it would actually produce more power in theory. and thats without any ECU or hell-ecktrickery.
Have I touched a nerve or something??? :rolleyes:

I wasn't comparing directly, just saying with lesser tech I'd expect less HP. But still more than just a few turns of a screw on the injector pump, which is what 99.9% of all Tdi tuners do.

BTW - the 4.6RV8 is no more capable than any other RV8 in terms of specific output and not really any more advanced and it is a 50's engine too.

In fact the 4.6 only ever made 225bhp in a Landy that's around 48bhp/litre, the 3.5 made 190 in the SD1 giving it 54bhp/litre

you cannot compare a td5 to a tdi - even though they both are 2.5l turbo diesel engines!
one is a 5 cylinder highly advance (well for a landie) computer controlled high revving diesel, with each injector in essence having its own computer controlled fuel injection pump. The other is a 4 pot heavy slogger with its engine design traced back 50 years!!!!!
thats like comparing an early buick v8 from the 1950s to the latest 4.6rv8 fitted to the last of the rangerovers!

Yes you can make a tdi produce the same sort of power per litre as a modern diesel. You can throw the pistons and crank and cam away for a start. Replace them with completely new lightweight versions made from unobtanium with the crank and cam redesigned for the appropriate valve durations.
then rip the head off and spend more hours than is entirely healthy grinding out every single bit of material you can for the best flow characteristics and fit the biggest valves possible without breaking into an oilway etc.
then scrap the turbo and fit a nice VNT version that matches the capacity and flow characteristics of your new head and cam and compression ratio. How you'd work that out without some really clever equipment and R&D facility i'm not sure.
then ditch the injectors, cos there is no way they will be able to deliver the quantity of fuel required in a short enough duration for this sort of power level.
then replace the fuel injection pump, cos there is no way that will cope with the volumes and pressures either.

once you have all the sorted out, you will get past your 100bhp/tonne mark.
But it aint a 200tdi any longer. and it would have cost you significantly more than a brand new competition ready LS engine/gearbox and a supertanker full of fuel!!!!!!



you cant polish a turd. A tdi is not built for high revving high HP outputs. The internals and valve durations, timing and fuelling just arent right for it. By comparison it is actually a powerful motor per revolution.

A tdi will rev to 4250rpm giving 0.026hp/rev
a td5 will rev to 5250rpm giving 0.025hp/rev
So if you could get a tdi to rev to the same limit as a td5 without it exploding, then it would actually produce more power in theory. and thats without any ECU or hell-ecktrickery.

Ummm, most of your "mods" listed above are petrol NA engine tweaks which are a complete waste of money on a turbo diesel.

Cams seem pointless, most turbo engines have next to zero overlap and more boost is the easiest and best way to get more air in.

The power/rev figure you've derived is commonly known as torque.:smokin:
350Nm shouldn't be a problem for a 2.5 TDI, but it will require more operator care (keeping cooling system working well etc).
Is there any rover V8 which produces 350Nm? Yes but it's a 4.6 and uses twice the fuel.

The fuel required to deliver 350Nm (around 80 cubic millimetres per shot) isn't high by any standards.

I have 300 tdi and the mods i have done are pretty simple and work

alisport intercooler bolt in item
K&N air filter
new larger exhaust

I really recommend getting someone with skill to tune injection pump
my 300 tdi had a problem with over fueling that ran EGT up with unspent fuel

Ed

So first you say you CAN'T compare them, then you DO compare them and admit that the Tdi is actually a pretty good motor. What is it that you really believe?

yes i did compare them - but only to show how different they are!
A standard tdi produces simillar outputs to a standard tune td5 in some respects. Yet we all know the standard tune in a td5 is wound all the way back to lowest common denominator due to worldwide fuel quality variations. You tune a td5 to its full potential (just through its ecu) to run on quality european high cetane diesel and the output differences between a tdi and td5 are leagues apart.
Then you have the ability to rev substantially higher in a td5 and you are not in even in the same ballpark as far as engine performance and power.

you cannot rev a tdi high enough (and expect it to live) to get decent power out of it. You cannot run a high enough boost level and fuelling to match to produce substantially more power without a) massively expensive modifications to prevent the head lifting off or melted engine components b) get a reasonable engine life.
the engine just isnt designed for it. You make the required modifications so that it can, and you end up with a different engine and a very empty wallet!


I love the tdi (i own 2!!!) but i know what its designed for and its limitations. If i wanted mega power then i would ditch it and install a td5 (have one of them as well) or fit a V8.

yes i did compare them - but only to show how different they are!
A standard tdi produces simillar outputs to a standard tune td5 in some respects. Yet we all know the standard tune in a td5 is wound all the way back to lowest common denominator due to worldwide fuel quality variations. You tune a td5 to its full potential (just through its ecu) to run on quality european high cetane diesel and the output differences between a tdi and td5 are leagues apart.
Then you have the ability to rev substantially higher in a td5 and you are not in even in the same ballpark as far as engine performance and power.

you cannot rev a tdi high enough (and expect it to live) to get decent power out of it. You cannot run a high enough boost level and fuelling to match to produce substantially more power without a) massively expensive modifications to prevent the head lifting off or melted engine components b) get a reasonable engine life.
the engine just isnt designed for it. You make the required modifications so that it can, and you end up with a different engine and a very empty wallet!


I love the tdi (i own 2!!!) but i know what its designed for and its limitations. If i wanted mega power then i would ditch it and install a td5 (have one of them as well) or fit a V8.

It's pretty clear the TD5 (and TDV6 and TDV8) are superior to the TDI for output across the baord, no-one is arguing otherwise.
But you seem to be comparing only peak power numbers, which is largely irrelevant for an offroad vehicle.
A turbo diesel producing x hp will be massively more useful offroad than a petrol V8 engine producing the same.

Don't get fixated on the hp, look at the torque that's responsible for that. Case in point my engine (Isuzu tdi) is probably producing less than 170hp peak but it has enough torque to squeal tyres in second on dry tarmac. That torque makes in unflinching offroad, it holds engine and vehicle speed rock solid. Other engines with huge amounts more power and less torque can't do that.

High peak power is only good for throwing mud.

The SD1 lump may have made more bhp/l but they did have proper fuel back then and considerably higher emissions. The 4.6 V8 is no more technically advanced in the mechanical construction, the difference is in the engine management and ultimately computers win against the abacus every time.

f'rexample the factory figures for the 3.5 lump are ~132bhp on carbs and ~165bhp on EFI, and that's just the flapper setup which is like having a ZX Spectrum run your engine, plus it retains the dizzy which is another restriction.

The more computing power you have, the more accurate you can be and the closer to optimum you can run everything.

I'd take slight issue with the idea that a bigger lump like the 4.6 uses more fuel - for the same performance in the same vehicle it doesn't, it's just that the bigger engine is capable of using more fuel if you put your foot down. I can get 20mpg from my 4.6 which, while not Prius territory, is OK for a big loud engine in a big loud low-geared car on mud tyres.

Veering back on-topic, the mention of the Isuzu engine provides an ideal case in point - you can buy one with a conversion kit for less than the price of a big intercooler and it will eat a Landy lump for breakfast.

The SD1 lump may have made more bhp/l but they did have proper fuel back then and considerably higher emissions. The 4.6 V8 is no more technically advanced in the mechanical construction, the difference is in the engine management and ultimately computers win against the abacus every time.

f'rexample the factory figures for the 3.5 lump are ~132bhp on carbs and ~165bhp on EFI, and that's just the flapper setup which is like having a ZX Spectrum run your engine, plus it retains the dizzy which is another restriction.

The more computing power you have, the more accurate you can be and the closer to optimum you can run everything.

I'd take slight issue with the idea that a bigger lump like the 4.6 uses more fuel - for the same performance in the same vehicle it doesn't, it's just that the bigger engine is capable of using more fuel if you put your foot down. I can get 20mpg from my 4.6 which, while not Prius territory, is OK for a big loud engine in a big loud low-geared car on mud tyres.

Veering back on-topic, the mention of the Isuzu engine provides an ideal case in point - you can buy one with a conversion kit for less than the price of a big intercooler and it will eat a Landy lump for breakfast.
I hear what you are saying and agree, was just trying to make a point. I still think 20mpg from a LR (109 isn't it?) is not an average mpg, not in real world driving. Well no more than taking a 6.0 litre V12 Jag, filling it up, resetting the mpg computer and getting on the motorway and cruising at 60mph - sure it'd then clock near mid 20's mpg, but it really didn't represent what the engine returned in real world use.

The SD1 lump may have made more bhp/l but they did have proper fuel back then and considerably higher emissions. The 4.6 V8 is no more technically advanced in the mechanical construction, the difference is in the engine management and ultimately computers win against the abacus every time.

f'rexample the factory figures for the 3.5 lump are ~132bhp on carbs and ~165bhp on EFI, and that's just the flapper setup which is like having a ZX Spectrum run your engine, plus it retains the dizzy which is another restriction.

The more computing power you have, the more accurate you can be and the closer to optimum you can run everything.

I'd take slight issue with the idea that a bigger lump like the 4.6 uses more fuel - for the same performance in the same vehicle it doesn't, it's just that the bigger engine is capable of using more fuel if you put your foot down. I can get 20mpg from my 4.6 which, while not Prius territory, is OK for a big loud engine in a big loud low-geared car on mud tyres.

Veering back on-topic, the mention of the Isuzu engine provides an ideal case in point - you can buy one with a conversion kit for less than the price of a big intercooler and it will eat a Landy lump for breakfast.

I was comparing the fuel consumption of a 4.6 vs a tdi. Probably didn't make that clear.

But yes bigger engines do use more fuel, the main reason is pumping losses. They spend more time with the throttle further closed which puts fuel economy right out the window.
The second reason is internal friction, bigger engines have more.

My Isuzu is the 3.9 litre 4BD1T, the 2.8 4JB1T (which you can buy kits for) is a great engine but the extra litre makes a massive difference.
Factory figures on the 4JB1T are similar to the 300tdi, but the Isuzu seems to be more robust.