In need of some tdi experts/guru’s

[nicks90]

go for it mate,

will be bloody interesting to see if the tdi engine holds together!

as for failures though, you need to look a little deeper. Check out how many people have tweaked fuel pumps/up'd the boost and then subsequently find their piston rings knackered from fuel wash - valve seats burning away from excessive EGT's, piston failures from poor spray patterns from the injectors not handling the additional fuel delivery, turbo bearing failures from high egt and increased pressures........

and its not jsut dumping nitrous in to make the engine big on power. As others have mentioned, its about the design of the engine and its intended use. The VW engine is designed as a revvy road motor, so is the performance V8 LSx.

think cam profiles, timing and all the other million items that are designed into an engine to match the intended use.

Main experience i have of this is with minis. In my younger days i liked to play around with the old 1275GTs. Fitting twin 1 3/4" SUs and a rc40 downpipe gave good results. But you change the cam for a high lift piper jobbie and profile the head to get rid of the kidney shape and increase the valve size and you get a MUCH revvier and livelier engine. Also upped the power nicely too.

so is the cam profile and combustion chamber shape, valve size etc on a tdi physically up to delivering those sorts of outputs? LR designed these with the criteria of super torque at lowest revs for offroad and towing and rubbish to total bhp.

[The Hatt]

go for it mate,

will be bloody interesting to see if the tdi engine holds together!

as for failures though, you need to look a little deeper. Check out how many people have tweaked fuel pumps/up'd the boost and then subsequently find their piston rings knackered from fuel wash - valve seats burning away from excessive EGT's, piston failures from poor spray patterns from the injectors not handling the additional fuel delivery, turbo bearing failures from high egt and increased pressures........

Yeah I know, but I've found it hard to find anything more than people saying about other people. Google doesn't exactly return a spreadsheet of conclusive results. So I tried this thread, which to be fair has seen quite a bit of interest but in all honesty hasn't actually provided any examples just claims that people have heard of....

So I started this thread: http://forums.lr4x4.com/index.php?showtopic=26003

But if you read it the reports of failures don't tally up with the claims in this thread

So what should I believe? Peoples opinions without anything to back them up or a more statistical analysis based on what data I can find.

and its not jsut dumping nitrous in to make the engine big on power. As others have mentioned, its about the design of the engine and its intended use. The VW engine is designed as a revvy road motor, so is the performance V8 LSx.

I do agree to an extent, not too sure how revvy a VW diesel is though, think they have PEAK HP at 4000rpm same as a tdi.

Also the whole aim of a power adder is to make big power without starting with a blank piece of paper.

think cam profiles, timing and all the other million items that are designed into an engine to match the intended use.

I agree if you are going for absolute maximum power or efficiency, but slapping a power adder (turbo, blower, nitrous) on to any engine will see an increase in power to some extent. Usually getting to greedy with that power is where most problems lie.

Main experience i have of this is with minis. In my younger days i liked to play around with the old 1275GTs. Fitting twin 1 3/4" SUs and a rc40 downpipe gave good results. But you change the cam for a high lift piper jobbie and profile the head to get rid of the kidney shape and increase the valve size and you get a MUCH revvier and livelier engine. Also upped the power nicely too.

Cool like the little Mini's, my cousin recently sold his 1275 GT Clubman.

But that aside, the tuning method I'm trying is deliberately not going down the route of expensive n/a style modification. I found out about the WON system by browsing a Ford Puma forum. There a user seemed to suffer very similar comments to these received here - as nitrous only breaks stuff and there are better ways. However they added a 50 shot and progressive controller and the car apparently runs very well producing over 200hp from a 1.7. The n/a option would have cost in the region of 3 times as much to achieve the same PEAK Hp but with lower torque and lower power across the rpm band.

I would NEVER say nitrous is the only route or that other tuning methods are a waste, because I simply don't believe it. I do believe there is a lot of miss-understanding about nitrous. Probably because of a lack of understanding and because there are some very carp setups out there which do cause a lot of problems.

Yes I'm a noob to nitrous, but not to tuning or performance cars/engines. And I believe for some £600 quid I can get a tdi to outperform most Rover V8's. Sure you could slap nitrous to a Rover V8 and walk all over the tdi, but then I don't have a Rover V8 in a Land Rover and I'd still be facing what would be for me unrealistic mpg figures.

so is the cam profile and combustion chamber shape, valve size etc on a tdi physically up to delivering those sorts of outputs?

Honestly I have no idea. But based on the fact that others claim 200hp without nitrous is possible from a tdi then yes I'd have say I think they are capable.

Also forgetting that nitrous is not as concerned with such things when making power. The heads/combustion chamber on a Rover V8 are pretty poor design compared to modern engines. But with the correct application they are fully capable of making power.

LR designed these with the criteria of super torque at lowest revs for offroad and towing and rubbish to total bhp.

I am happy to admit that I have no idea what criteria LR used when designing the tdi. Yes it probably wasn't for Formula 1 racing but its a bit of bold statement to claim what you are claiming. The tdi had a massive hike in HP & torque over it's predecessor. And in performance terms was successful in causing the 3.5 V8 to be taken out of production for the Defender.

As for HP and torque, well they are interlinked. HP is in essence a representation or torque at speed, or work done if you prefer.

HP = torque x rpm / 5252

Torque = HP x 5252 / rpms

The more torque you make the more hp.

The more torque you make at higher rpms then even more power.

Example:

A tdi makes about 195lb ft @ 1800rpm. This equates to only 67hp at this rpm.

If you could add a 100lb ft extra at this rpm you'd get 101hp @ 1800rpm. A relatively small increase in HP compared to the amount of torque.

At the other end of the spectrum a stock tdi makes PEAK power of 111hp @ 4000rpm but at these higher rpms you only need to make 146lb ft of torque.

If we could then increase this torque by the same 100lb ft to give us 246lb ft we'd see PEAK HP of 187hp.

This of course assumes the power/torque curves remain constant.

This is also the reason diesels make less PEAK HP that petrol engines. Petrol engines simply spin faster. A Honda Civic Type-R only needs 122lb ft @ 8500rpm to produce its 197hp.

[andyb]

This is also the reason diesels make less PEAK HP that petrol engines. Petrol engines simply spin faster. A Honda Civic Type-R only needs 122lb ft @ 8500rpm to produce its 197hp.

I don't think that is nessacarily the whole reason.

The torque of an engine is also a function of the bore/stroke relation and thus the 'throw' of the crank.

The length of the stroke of the engine will also determine piston speed which is why longer stroke engines are usually torqueir but have lower peak revs. There is also cam lift and duration to take into account as well......but we are getting waaaay off the original thread topic now

[The Hatt]

I don't think that is nessacarily the whole reason.

The torque of an engine is also a function of the bore/stroke relation and thus the 'throw' of the crank.

The length of the stroke of the engine will also determine piston speed which is why longer stroke engines are usually torqueir but have lower peak revs. There is also cam lift and duration to take into account as well......but we are getting waaaay off the original thread topic now

I agree generally long stroke motors are more torquey. But hp is still calculated from torque in exactly the same way so it doesn't matter about the engine configuration.

Also evidence on long stroke motors making more torque is a little bit of a grey area. One of the hot rod mags in America built to engines as identically as they good but one with a longer stroke than the other but same displacement. Both made very similar torque curves however the shorter stroke motor made slightly higher HP due to being happier at higher rpm levels.

[dollythelw]

If you've got a problem email Trev @ WONm and take it up with him for pity's sake.....

Im not the one with the problem, Im not a blue bottle virgin - and I dont need your pity spanky

[The Hatt]

Im not the one with the problem, Im not a blue bottle virgin - and I dont need your pity spanky

could have fooled me

[dollythelw]

I'll bow to your E wisdom - crack on

[FridgeFreezer]

Jez you f***ing amateur, what have you ever built eh?

[RedLineMike]

If i didnt know otherwise i would say this guy reminds me of dew110csw wots his face LOL

[will_warne]

Hi and thanks for replying to the thread.

You along with a few others are citing broken cranks and rods as a problem. Now I'm not disputing this fact but so far the only example I've found is of someone running a non LR OEM crank.

Do you know of any examples where these failures have actually occurred? I ask because I'm not researching this as a full time profession and so far my research does not support these conclusion.

As I said in one of your other thread - I've seen first hand several road and crank failures. That's without even thinking about knackered pistons / bores / rings / valves due to getting the fuelling wrong and either washing bores or giving too high a cylinder temperature.

I think this is only partly correct. Bolt on mods generally "free" HP which is lost by the setup, this generally places no extra strain on the engine itself. But yes you will reach a level where gaining a few more HP will cost a heck of a lot more. But considering the level I'm starting at I don't feel I've perhaps reached this level yet.

I beg to differ. Any more power or torque over standard will put more stress on the engine particularly as extra bhp often comes with extra rpm. Yes it’s less of a case on forced induction engines but you are then increasing the torque with similar effects.

Why not? Loads and loads of other people do, and to a very wide variety of engines.

No I'm not claiming this is proof that all or any engine will be ok, but on the other hand I don't think such a generalised statement is any more accurate or representative of the real world either.

There are lots of people in the world who are not overly blessed with intelligence..... Fair enough if you want to make an engine that will last 5 minutes before you throw another shagged lump in then be my guest. It’s a really inelegant solution.

I agree which is why I've been wanting to find out some real world examples of where these engine fail.

If you took a car petrol engine an added nitrous until it broke you'd probably expect it to be pistons, rods or head. So to up the anti you'd probably fit forged pistons and stronger rods.

So I guess a question is does a tdi motor have forged pistons as stock? Considering the high CR and the addition of a turbocharger I'd have thought so. But insight from others in this matter is welcome.

You're going to run into most of the same problem be it petrol or diesel - more power means more stress on the mill meaning an increased chance of things going pop. For this sort of power I'd certainly be looking to throw away the entire bottom end bar the block.

Well ok. But where does traditional tuning end and start? Or what is even traditional tuning? The tdi has a turbo which is hardly traditional.

Also if I want to add a high lift cam I'll need to account for higher rpms, more boost means possible a better turbo and increased pressure, a ported head is astronomically expensive with likely small gains.

By traditional tuning I meant getting more fuel and air into the engine using hard and soft tuning. That means cams, ports, induction, exhausts and boost for air and then injectors and FIP for fuel.

Given your comments so far I'd suggest doing a bit more reading. Porting done well will always help an engine. As for small gains that's simply depends on your flow requirements - a lot will depend on your choice of cam profile. As for a high lift cam pushing the power band up the rev range this is only partially true - get the valve timing right with a not too wild cam and you'll see benefits throughout the rev range.

As far as costs go I simply don't understand why you'd be getting a head from someone else when a) your budget is tight B) your trying to embark on a fairly complex DIY project and c) its not rocket science. It may take a while to port a head (hence the price) but it isn't that difficult. Getting someone else to do it for you is a luxury!

I AM listing, so if you where to max out the traditional route what would you do to a tdi?

I'd have a new crank machined from solid, rods made, pistons ceramic coated, rework the head, VNT turbo chosen to give power over a nice broad rev range, new injectors, rework the FIP, optimise the oil pump, sort out the oil cooling, open up the governor to allow it to rev a little higher. I'd also add propane injection as this will make the best use of the fuel your able to get into the engine. I would not expect change for £8 - 10k for this to get it done right.

Bearing in mind I have already modified the exhaust, have a full width intercooler, upped boost and a tweaked injector pump.

Then the next thing you want to do is fit a more suitable turbo, an EGT gauge and tweak the pump some more. Possibly fit propane injection but realistically your reaching the limit of cheap increases in power.

[white90]

Well said Will except:

Then the next thing you want to do is fit a more suitable turbo, an EGT gauge and tweak the pump some more. Possibly fit propane injection but realistically your reaching the limit of cheap increases in power.

This bit should have said

But realistically you are dreaming and winding people up.

As speed costs money and it appears you may be lacking this a little for your desires

Have you considered joining the Vapour builders?

[Les Henson]

Have you considered joining the Vapour builders?

Les

[Hybrid_From_Hell]

Thank gawd for that

this muppet was beginning to make both Mortus and Dew110 look sensible

Is the silly season now closed - please

Nige

[Happyoldgit]

Thank gawd for that

this muppet was beginning to make both Mortus and Dew110 look sensible

Is the silly season now closed - please

Nige

I think so - especially as far as this thread goes.