 | Home > Technical > First post - Getting the most out of a 2.5NA |
 
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| Boost Member Since: 17 Oct 2014 Location: Gloucestershire Posts: 203   
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Hi guys, I've been lurking on this forum for a while and have decided to join it
 I've got a 1986 90 which is in desperate need of a 200tdi swap however at the moment I'm forced to endure the biblically slow 2.5N/A lump  . I've replaced the engine oil which hadn't been done for 4 years as well as tweaked the max fuel and timing settings on the injector pump which I've written about in my blog http://autoadrenaline.wordpress.com/ (for anyone who's interested), however besides porting the head is there any way I can extract some more horses from this engine? Cheers anyone who replies  |
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26th Oct 2014 10:01pm |
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| LR90XS2011 Member Since: 05 Apr 2011 Location: bickenhill Posts: 3664 
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it is very likely that the biggest restriction for a 2.5 it is very small bore exhaust , I'm not sure how easy it would be to fit a none cat exhaust off a later model but they are much bigger bore and should allow the engine to breath more easily especialy as the revs rise. This is also likely to be a relatively cheap mod if you use second hand parts. I know a chap that fitted the main parts off a TD5 exhaust to a 2.25 petrol and reported a noticeable difference.
I would warn anyone to be careful adjusting the injection timing as this can lead to engine damage. DEFENDER 90 TDCI XS, I hope everyone is well and your land rovers make you happy |
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27th Oct 2014 7:18am |
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| CFB Member Since: 13 Sep 2007 Location: Bradford, West Yorkshire Posts: 803
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The OP states clearly he has already done the fuel pump/injector tweaks! Andy
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27th Oct 2014 8:20am |
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| cornish rattler Member Since: 31 Aug 2013 Location: Manchester Posts: 642 
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Sorry andy missed that bit
yeah mine is a 2.5td fitted with a defender 200tdi by the p o complete with new exhaust system but when i decided to fit a straight through middle pipe i found out that the exhaust system that was fitted was a 2.5td exhaust with a slightly smaller bore to the tdi exhaust and had to replace the full system with a tdi system it fits in egzackly the same way as the 2.5td exhaust did but the exhaust brackets are in a slightly differend place so you may need to make the brackets fit but the tdi exhaust will fit  Graham
1988 Defender 90 county 200tdi ( Beast ) Paul Walker 1973-2013 ( I Almost Had You ) |
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27th Oct 2014 9:37am |
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| udderlyoffroad Member Since: 18 Jul 2011 Location: Bristol Posts: 124
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No tips as such, but I notice you're in Gloucestershire...it so happens I have a 200 Tdi Discovery sat on my drive (in Bristol) which I was going to repair but just don't have the time at the moment. PM if interested...
Matt Real trucks don't have spark plugs |
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27th Oct 2014 10:25am |
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| Dave-H Member Since: 08 Feb 2011 Location: Surrey Posts: 1507  
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Welcome Boost
LOL - Been there done that many years ago with my first 90 [a 2.5NA] Bottom line is you'll never do anything that will make a noticeable improvement without spending serious money. The 2.5NA is what it is, an underpowered oil burner. Even pump adjustments, big bore exhaust, better air intake etc etc will only make a few BHP difference, and on an engine pushing a near on 2 tonne brick at 68 BHP as standard, you're not going to make much of a impact.  Guns and Landrovers .... anything else is irrelevant. |
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27th Oct 2014 11:24am |
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| Dobby Member Since: 23 May 2012 Location: East Seaxe Posts: 187 |
I'd be interested to know how you get on, will you add a new blog post?
I've got a 25NA too.. and while I can live with the performance, it'd be nice to know what's possible. IIRC they only had 67BHP from new, so I'm doubtful there's much you can do. Have you asked the same question on Landyzone - JamesMartin is usually pretty helpful in the 2.5 N/A forum. http://www.landyzone.co.uk/lz/f54/ |
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27th Oct 2014 12:01pm |
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| Boost Member Since: 17 Oct 2014 Location: Gloucestershire Posts: 203
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Hi guys thanks for all the responses
 Dobby if you look at the last paragraph or so on that blog post it details what the differences were after tweaking the max fuel setting. As far as timing goes I only advanced it very slightly, I think this made it slightly quieter (probably a placebo effect) however it didn't give it any more power.
"Whilst not a massive improvement, adjusting the fuelling this way meant that I no longer had the accelerator pedal flat to the floor everywhere just for normal driving, this alone made a big difference to how the 90 felt to drive. Now the pedal only needs to be pressed a little from idle and it provides more power than it used to and is quieter too, I also have a feeling that it’s using less fuel as after accelerating up to cruising speed (40-50mph) it burbles away and sounds very unstressed." Having driven it for a while like this, it's definitely better than it was before (quieter and low down torque slightly better) however it's still frustratingly slow!
Regards, Boost. |
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27th Oct 2014 12:16pm |
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| roel Member Since: 08 Aug 2009 Location: Lelystad Posts: 2039  
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My first 90 was a 2.5 na and with 11 years and 250.000 km it wasn't very new at that time but it could cruise? at 120 km/hr without headwind and hills off-course. Yes it was n't powerfull but OK for the first years.
I rebuild it with a 3.5 ltr V8 that was a lot better.  Roel
1984 90 2.5 na Diesel - RR V8 (1994-2001) 1997 Camel Trophy Discovery 300TDI (2001-2009) 2005 G4 Discovery III 4.4 V8 (2008-2018) It's gone but it still hurts. 2003 90 Td5 (2009-now) |
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27th Oct 2014 8:02pm |
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| Boost Member Since: 17 Oct 2014 Location: Gloucestershire Posts: 203
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Would putting a bigger exhaust on mine (at the moment it's got a standard britpart system with a massive middle box) be worth the increase in noise for the power it would give? Obviously a V8 would be better
 haha but I'm looking at getting a 200tdi up to around 150bhp sometime, that'd be a decent increase over the 2.5NA  |
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28th Oct 2014 10:43am |
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| Martin Site Admin Member Since: 02 Apr 2007 Location: Hook Norton Posts: 6658 
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I do have to giggle at your username, given the engine
 1988 90 Td5 NAS soft top
2015 D90 XS SW |
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28th Oct 2014 1:39pm |
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| Happyoldgit Member Since: 14 Sep 2007 Location: Norfolk Posts: 3471 
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TBH just keep it well serviced and in good fettle and come to terms that you are never going to get 2014 eurobox diesel type performance out of an oil burner that was deigned and produced decades ago. NA's are robust units which is more than can be said for the 2.5 TD. Steve.
Owned numerous Land Rover vehicles of all shapes and sizes over the decades. Current Defender: A non tarts hand-bagged Puma 110 XS USW. [Insert something impressive here such as extensive list of previous Land Rovers or examples of your prestigeous and expensive items, trinkets, houses, bikes, vehicles etc] http://forums.lr4x4.com I used to be Miserable ...but now I'm ecstatic. |
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28th Oct 2014 5:09pm |
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| Fatboy Slim Member Since: 04 Feb 2008 Location: Bridgend Posts: 1006 
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Boost, there is no way to sugar coat this: you are never going to get anything that resembles 'performance' out of that motor. Sorry to tell you that but hate seeing people wasting time and money on something that is never realistically going to be any better than it is. Retire it into a canal boat or something like that mate, its the kindest thing to do
Ps please excuse the brutal honesty |
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28th Oct 2014 7:47pm |
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| Dieselhead Member Since: 21 Oct 2012 Location: Pulborough. West Sussex Posts: 552 |
I have to sell a discovery 1 3.9 V8 Auto to get rid of
Put the engine & box in your 90 = BOOST Chris
2008 XS 110 2.4 Utility. Tonga Green 1953 Series 1 for restoration 1983 Mini Mayfair 2004 VW T5 Camper 2008 Diahatsu Sirion. Thats hers Classic Bolens Garden Tractors |
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28th Oct 2014 8:53pm |
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