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Dont laugh-but my 2.5NA 'performance' project


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yes I know-rip it out and stick an ex-Disco tdi in. However its a long story-but its staying. Its running fine-I've compression tested it-good results, uses no oil or water, no blow by, starts well, no smoke, pulls fine, timing is spot on, fuel filters changed, new lift pump, but a little more grunt is always nice. The engine will be going to Turners for rebuild.

Anyway,I have a brand new-never fitted gas flowed head as fitted to the last of the 2.5NA's and as used by the Army rally team when they used the N/A 90's following tuning work by Ricardo (who developed the Wolf LR's), this will be going on come rebuild time. Its allready fitted with a stainless mid pipe silencer replacement pipe to aid gas flow in preperation for the new head.

Air Inlet will be aided by a Mantec snorkle with a Safari head to help with the 'ram air' effect The standard 2.5NA inlet manifold is right behind the radiator and draws in engine warm air- TDIs dont suffer because of the intercooler and the side wing inlet. The air box 'duck bill' is removed and sealed. The snorkle will allow colder air at hopefully slightly higher inlet pressure than the standard setup. The aluminium inlet manifold casting will be smoothed internally and possibly enlarged slightly.

Two further options Im considering are;

1. A performance cam by ACR ( http://www.automotivecomp.com/landrover_perf.html ). Now I know its for the 2.5 petrol but the petrol and diesels engines share the same camshaft (also does the 200tdi), so a question is-has anyone ever fitted or played around with a performance cam in a N/A or 200tdi? The website says-higher rate of valve opening and lift, so does that equal more air into the engine on a diesel? this plus a recalibrated fuel pump = increased power?

2. Tubular manifolds. The standard cast manifold looks very restrictive, my ported head and possibe cam will allow more gas flow into the engine and my exhaust has an increased capacity for gas flow but it could all be throttled by the restrictive exhaust manifold-hence the idea of tubulars.

Has anyone played around with tubulars manifolds on a diesel (I know they're quite common on V8's)?

Any other ideas? apart from bolting on a 19J turbo or fitting a V8/TDI/TD5 etc etc?

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There was an article in one of the mags ages ago about someone 'tuning' a 2.25 diesel, I don't know what else he'd done but he had tubular manifold and a bigger bore exhaust made to good effect... can't really give any more info though.

Brian

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If it keeps you amused then go for it, although I'm sure people will be curious about why you're doing this as it makes very little sense from a time/effort/money Vs performance gain point of view :unsure:

What about propane injection?

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Air Inlet will be aided by a Mantec snorkle with a Safari head to help with the 'ram air' effect

I sincerely doubt an extra yard of intake plumbing is going to aid air induction, and I don't think anyone has ever come up with any evidence of a ram-air effect outside Safari Snorkel's sales blurb. It's not a V2 rocket. I'd look at sticking a 110 V8 filter in, they're the size of a dustbin so should let it breathe more freely should the standard filter be insufficient.

The aluminium inlet manifold casting will be smoothed internally and possibly enlarged slightly.

Don't smooth it too much or you'll ruin the airflow, air likes a matte surface not shiny.

Any other ideas?

Supercharger, propane, NOS, diesel-electric hybrid, twin engines, convert it to two-stroke...

Ricardo have done more than a little engine tweaking over the years, check Wikipedia for some inspiration :P

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Hi

My comments in bold

Air Inlet will be aided by a Mantec snorkle with a Safari head to help with the 'ram air' effect

I sincerely doubt an extra yard of intake plumbing is going to aid air induction, and I don't think anyone has ever come up with any evidence of a ram-air effect outside Safari Snorkel's sales blurb. It's not a V2 rocket. I'd look at sticking a 110 V8 filter in, they're the size of a dustbin so should let it breathe more freely should the standard filter be insufficient.

I have done some measurements on such a set up and the conclusion was that below 50mph there was more restriction with a snorkel set up and above it gave a tinny tinny less under presure in the inlet manifold, I can not remember the figures it is close to 10 years ago, so you are right John.

It is much more important to make shure that the engine gets coold air from outside the engine bay every time you increase the inlet temp by 10 C you lose rouhgly 3% hp :(

The aluminium inlet manifold casting will be smoothed internally and possibly enlarged slightly.

An 40-80 grit grind surface is usually ok.

Don't smooth it too much or you'll ruin the airflow, air likes a matte surface not shiny.

Any other ideas?

Supercharger, propane, NOS, diesel-electric hybrid, twin engines, convert it to two-stroke...

Ricardo have done more than a little engine tweaking over the years, check Wikipedia for some inspiration :P

And as others have mentioned it is not at all cost vise a good idea, but for the expeience it is very good and fun and good to learn from

Regards

Ole

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On the ram air issue - I recall reading an article about it when motorcycles first started using it. IIRC the general outcome was that it made a less than 5% improvement in power at speeds in excess of 150mph and was only worth doing if you are chasing ultimate top speed figures - as sports bikes were at the time. IMHO the additional drag of the snorkel tube (internal and external), and the generally lower speeds that Land Rovers are expected to work at, negates any ram-air effect. The fact that you will be drawing cold air though - now that is worth having (how about using a naca duct at the front of the bonnet - that would be so cool :) )

With regard to tuning a 2.5 N/A - well it's a bit like the old joke about asking a Yorkshireman for direction and he replies "Well if I was going there, I wouldn't start from here.." ;) It certainly seems a strange thing to do, but for that reason alone I think is worthy of respect - go for it, and I hope you get excellent results - I will be watching this thread with interest :)

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Been there... :)

What I did was to get a "new head" from Turner. They called it gas flowed, but I assume it simply was of the newer type. Not much happened with the performance after I installed it, but after adjusting fueling on the IP, there was a significant improvement in torque.

I also had a snorkel, but with a Cooper top. That decreased performance due to the long air path. Removing the intake muffler on the air cleaner and turning the intake away from the heat made a little positive difference.

I have a feeling that I read somewhere about "racing" cams for a diesel and the conclusion was that it won't work. Not sure about that, though. Anyway, diesels go out of puff at higher revs anyway, due to the fact that there isn't time enough to suck in more air every time the inlet valves are open.

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I'm surprised the cams are the same, because traditionally diesels run very low (or no) overlap and a very short lift duration on the camshaft, due to the extremely tight clearances inside the combustion chamber. Petrol engines tend to have a bowl in the piston or head, which means you can leave the valves open much later in the stroke, without the pistons mashing them, but due to a derv running a far higher compression ratio theres simply not enough room.

The wide adoption of turbochargers in diesel engines is exactly beacuse of this issue. You cant open the valves any more to get better aspiration, so your left with the option of ramming the air in with a turbocharger instead!

If the stock cams ARE the same, then the performance cam will certainly be adding overlap and lift as well as increasing the duration, as this would hugely increase the performance on a petrol engine, however i suspect on a derv all you'll end up doing is bending valves, or breaking rocker arms.

While yes, its good fun, i just dont see the point. The first engine i built was a great learning experience, but there was also a huge positive benefit at the end, as i'd taken a snotty carb fed engine, fitted a cylinder head from a different model with huge valves and added an EFI system, going from about 70hp to about 90hp in the process. Had i done all that work, and spent all that money, and come out with a 2% increase in power, i'd have been seriously Mildly miffed!

Why not apply all the work to an engine thats worth doing the work to?

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Hi

A little more info, I have done the porting and manifold matching on a 2,25 diesel way back 20 years ago fuel up by 15% freeflow exhaust 2,5" and an very unrestricted airfilter with cold air feed, I had for the size off engine, load off pulling power, could not prowoke black smoke at all it gave, when I cruised at 50Mph, more than 10% better milage, but it would almost outrun it self in the higher rev range so one had to be carefull.

Re the cam on the 2,5 na diesel and petrol the cam is the same, to me it says a lot about how de-tuned the petrol engine is.

I have heard of people using the ACR cam in 200Tdi's but I have never heard off how the result is.

I have my self drawn all the pre 300tdi 4 cyl landrover cam profils on paper also the ACR performance one, it has not much more lift and not a lot more duration but it has faster "raise" times on the lobes, wich is possible because thes engines have "roller" cam followers as far as I know.

In other words the area under profile is larger without having a lot more lift and duration, tha tis also why ACR cams are made from blanks and not just regrinds.

And Aragon you are right re cost and result, but he aksed us not to laugh so we wont because some us has been there just because it was possible not everything in life has to be rational :D

So go for it

Regards

Ole

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ignore them and do it!

If you have the cash and the inclination and the will to do it - why the hell not?

Yes for the same money you could stick a tdi donk in there with a bigger I/C and tweak the pump and get 140bhp... but wheres the fun in following a tech archive post line by line?

You wont make much more power out of that diesel, but i bet it will be fun.

Couple of ideas?

How about ditching the snorkel (which is very restrictive due to its length, angles, bends etc) and put a cold air feed pipe going to the front of the wing and fit a small but high flowrate intercooler inline? That way you will definitely be getting colder air and with the intake facing forward in a straight line from your intake manifold, you WILL get a modicum of air pressure as you travel forward. Plus the straighter and shorter the intake pipework the better.

plenty of chav sites sell cheapy cold air inlet pipes with the silly chrome end finishers, think hellfrauds do them to. can be hard to fit on on the wing of a 90 as there's plenty of room.

If it does reduce intake temps - even slightly - you can then tweak the fuelling slightly to take advantage.

I'd also ditch the viscous fan and go leccy. every little bit helps!

If you're feeling strong and brave, you could even ditch the power steering too. Not sure how much it takes to run that system, but when it comes to a 2.5na every little bit is ALOT!

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Yeah, run the air intake as straight as you can from the front grille with a venturi and you can probably get some real ram-air effect once you get up to speed. Probably good for 10HP at highway speed, possibly more depending on how much venturi effect you can manage. Think of a loudspeaker facing forward, I'm sure there's someone out there with fluid dynamics background that can give you the optimal proportions, the only downside is water separation in the rain but there are solutions for that as well.

Could fit two of those 'heater intake ram air scoops' and pull your intake air from both wingtops.

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The ram air affect is a waste of time and effort.... It is only useful for race cars doing 200 mph.

The math is simple. Velocity pressure is 1/2 * density * velocity squared.

At 110 km/h .... Pressure = 1/2 * 1.2 kg/m3 * 30.56^2 m/s = 560 Pa. 560 pa / 101325 Pa = 0.0055 or 0.55% increase in pressure and air density.

Intake porting and exhaust work will probably help a lot more. In the end, you might gain 10% in top end power with all the things you are doing. Bottom end will not change. You will need it to be quite smokey in order to maximize power.

Make sure your injectors are in top nick.

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Miserable sod. :(

I think it is a great project. I just wanted to point out that spending effort on the ram thing was not worth it. As stated, getting cold air is more important. Freeing up the air flow, getting as high a compression as possible, setting the timing correctly, making sure the pump and injectors are as good as possible are the things to focus on.

Here is a good controversial topic to consider for seating in the rings to the bores.... http://www.mototuneusa.com/break_in_secrets.htm

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okay, thanks for all the comments so far-keep them coming!

A couple of things then;

I run the 110 with the fan removed all year round-the cooling system is in good condition (new rad&water pump) and has never gotten anywhere near hot either whilst slogging up Shap summit or idling in traffic. Removing the fan makes a noticeable difference to power output though so I might be going with a Kenlowe allthough the fan lives in the back of the 110 at all times in case its needed.

I removed the PAS belt a few months ago and whilst there is a slight noticeable gain to be had its not really worth loosing the PAS for, however I was thinking along the lines of driving the PAS pump through a 12V clutch coupling so you can 'disconnect' it when on the motorway or where you didnt need assistance.......but then dismissed the idea from an insurance point of view.

The resonator/inlet silencer was removed ages ago, I did consider turning the air filter inlet round to the front of the 110 but water admission coming through the radiator put me off the idea-especially as I've removed the 'duckbill' and sealed the whole airbox up for use with the snorkle. Any ideas for water seperation?

The injectors are new and set at the correct 135bar cracking pressure, I do have another new spare set which Im going to set at 150bar as I've been told by a reliable source that it helps the spray pattern. The IP is going to be rebuilt when the 110 is stripped down.

Timing is spot on and set by the N/A timing pins and double checked with my AVL dynamic diesel strobe light.

Regarding overfuelling and increased EGT's what is a reliable maximum figure before pistons/heads start melting/cracking? To be getting up near these higher temps-are we at the levels of overfuelling that produce seriously large amounts of black smoke?

Again, I know ripping the old donk out and sticking in a Tdi/TD5/V8 etc etc is far easier/cheaper, BUT for a few reasons I'm not going down this route-the N/A is staying so is the 110 that its in. End of!

I'm not wanting to go faster than my current 55-60mph 'cruising' speed, ideally Im just looking for a bit more torque to stop me dying on hills as much when fully laden.

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I admire your enthusiasm :)

I would leave the PAS connected I think.

Surely it only uses a noticeable amount of engine power when it's actually doing some work (ie. turning at slow speed), as otherwise it's just pumping fluid round a fairly open circuit and so the drag on the engine would be negligible under most conditions when power would be required (motorways etc. as you say)?

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How about electric PAS, either direct drive or electric pump?

Again I've looked into-there's lots of info out there;

http://ecomodder.com/forum/showthread.php/converting-power-steering-electric-power-steering-1100.html

....but Im a little put off by modifying a safety critical part of a quite heavy Landrover, I think I'd rather leave the PAS as it is, allthough I'd like to try a non PAS Defender at some point to see just how heavy a manual steering box is compared to my 6bolt Gemmer box with the drive belt removed experiment.

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I think it is a great project. I just wanted to point out that spending effort on the ram thing was not worth it. As stated, getting cold air is more important. Freeing up the air flow, getting as high a compression as possible, setting the timing correctly, making sure the pump and injectors are as good as possible are the things to focus on.

Here is a good controversial topic to consider for seating in the rings to the bores.... http://www.mototuneusa.com/break_in_secrets.htm

Hi

That is they way to do it, we have done so in almost 20 years now with great succes, so go a head.

Regards

Ole

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Timing is spot on and set by the N/A timing pins and double checked with my AVL dynamic diesel strobe light.

Maximum power is probably slightly advanced from the pins, especially if you increase injector pressure. It is something you can play with when done. Adjust until you hit peak power...

Regarding overfuelling and increased EGT's what is a reliable maximum figure before pistons/heads start melting/cracking? To be getting up near these higher temps-are we at the levels of overfuelling that produce seriously large amounts of black smoke?

Keep the continuous EGTs below 700 C. It will be smoky as hell on a non-turbo engine.

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I seem to remember from an old post on here, that using injectors from a certain Peugeot will get you a little more power. Reason was that these lack the little extra hole the Land Rover version has for easier starting. Search, and you might find...

New head can be bought from Turner Emgineering, or at least could when I got one.

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  • 3 months later...

Hi

A little more info, I have done the porting and manifold matching on a 2,25 diesel way back 20 years ago fuel up by 15% freeflow exhaust 2,5" and an very unrestricted airfilter with cold air feed, I had for the size off engine, load off pulling power, could not prowoke black smoke at all it gave, when I cruised at 50Mph, more than 10% better milage, but it would almost outrun it self in the higher rev range so one had to be carefull.

Re the cam on the 2,5 na diesel and petrol the cam is the same, to me it says a lot about how de-tuned the petrol engine is.

I have heard of people using the ACR cam in 200Tdi's but I have never heard off how the result is.

I have my self drawn all the pre 300tdi 4 cyl landrover cam profils on paper also the ACR performance one, it has not much more lift and not a lot more duration but it has faster "raise" times on the lobes, wich is possible because thes engines have "roller" cam followers as far as I know.

In other words the area under profile is larger without having a lot more lift and duration, tha tis also why ACR cams are made from blanks and not just regrinds.

And Aragon you are right re cost and result, but he aksed us not to laugh so we wont because some us has been there just because it was possible not everything in life has to be rational :D

So go for it

Regards

Ole

Would you be able to scan these cam profiles and send me a copy, I've been trying to get hold of something like that for ages. I'd really appreciate it.

Thanks

Dan

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