Update on the 2" exhaust for the 200Di conversion.
The old 2.25 exhaust on my 200Di Landy was due for replacement, and although it performs remarkably well with that exhaust I felt that it would be better with an exhaust which matched the engine size. Using the 2.5NA (fitted to early Defenders) as a reference I found a there were a couple of 2" exhaust systems available.
Steve Parker's have a '2.5NA to Series exhaust' system for £600 + postage, but I opted for the Rimmer Bros 'Stainless Steel Series 3 diesel big bore 50mm' system which cost me £345 with postage.
There were no clips supplied so I had to re-invent most of the hangers and clips. The silencer is a push-fit rather than bolted, but this goes on quite easily using a 50mm exhaust clamp and doesn't leak. The standard downpipe is tricky enough to manipulate past the gearbox crossmember (if you remove the front wheel) and the new wider one is even more of a challenge but can be done if you jack up the vehicle another 6 inches.
Test conditions: (4 speed std box, 750 tyres, 3.5 Range Rover diffs, no overdrive.)
So today I tested out the complete set up today. For comparison (and out of curiosity) I've left the fuel mixture screw as it was (ie set up with the 2.25 exhaust).
For the record the procedure is to gradually turn the screw in until you see black smoke on harsh throttle, then wind back until the smoke is barely visible.
It's possible to get a lot more power if you are prepared to have lots of smoke (this suggests that the engine is capable of delivering more but possibly needs more airflow?)
but you need to compromise. The last time it needed adjusting was when I changed from a full flow air filter to a standard filter, hopefully I won't need a full flow filter because they are so noisy in the cab.
As I said I haven't changed the fuel screw yet for this initial exhaust trial as I want to see the difference before and after. The engine was running slightly faster at tickover which suggests the fuel mixture to the chambers has changed slightly, and so there could be room for adjustment. There was no black smoke (if anything it would be running lean) so it was safe to try without damage.
Verdict so far:
I'm not seeking or expecting massive acceleration but I do want to get the maximum potential from a 2.5 direct injection diesel engine.
It certainly sounds the part, more like a Defender (as opposed to sounding like the 'phut phut' from an old Commer van!).
Driving it was more like driving a Defender (without the turbo boost). Not a massive increase in acceleration but the engine seems less laboured when accelerating and 3rd gear has become more useful in that I could make a turn from an A road up a steep hill without changing down to 2nd. It's certainly better to drive.
It easily managed to get to 70mph on the M69 comfortably without too much struggle or engine noise. The engine temperature remained stable throughout.
There is some potential to up-fuel it slightly and that will be my next test, and I'm expecting an improvement.
The aim is to extract the most efficient gain from the engine to within its design capacity, so I don't want to mess with the air intake.
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