THE ROVER 75 & MG ZT
DIESEL PAGE
My 2002 75 CDT Classic Se 116 in Midnight Blue. 99k miles, but feels like 50k.
WELCOME TO MY ROVER 75 AND ZT DIESEL PAGES:
THE ERA OF LOW COST PERFORMANCE UPGRADES FOR YOUR 75 & ZT DIESEL HAS ARRIVED
A healthy 144bhp from my 116 and 160bhp from a ZT135 click here
Index:
FIRST IMPRESSIONS
ody colour grille & non Rover fogs.
BUY ONE WHILE YOU CAN - THEY ARE TOO GOOD TO MISS
I can now understand why the 75 received the numerous accolades it did on its launch. It is a big step up in the refinement stakes compared to the 45. The ride is superb - it glides very serenely along oblivious to the nature of the road surface, with tyre noise well subdued. Even with 92000 miles on the odometer, this 75 felt like new.
The engine benefits from larger and more sophisticated hydraulic mounts, plus a heavier flywheel and there are 2 bulkheads and thick sound insulation isolating it from the passenger compartment. Consequently it is very quiet and smooth, making the L series sound a bit agricultural and quite noisy in contrast. (I can now understand why it wasn't used in this car!)
This particular car does not suffer from the low down lethargy which disappointed me when I drove my first 45. I'm lucky - the maf sensor is fine and looks to have been replaced quite recently. Other 75/ZT owners are now contacting me with feedback, having bought and fitted a Mafam to cure the poor performance below 2000rpm. Whilst I and others are enjoying their 75 or ZT having given it a new lease of life with one of my TU3 Common Rail Power Modules.
However in standard form, the throttle response is 'lazy' - it needs a lot of pedal movement to generate a wake up call, and the pedal has to be squashed into the carpet to get all 111 horses galloping. On the other hand, it is very easy to drive smoothly even in heavy traffic and the good low down torque & smooth engine means it will trickle along at barely more than 1000rpm in any gear. Unfortunately, no sooner have the horses got going than they run out of steam again at just over 3000rpm as you can see from the purple line in the chart. Also note that even with a good maf, max torque is not at MGR's claimed 2000rpm, but at about 2300rpm., though the figures of 192lbs ft and 115bhp are spot on for a CDT.
Overall the performance is comparable to a 1600cc petrol hatchback but with the diesel's low down torque permitting fewer gear changes. Adequate, but often not enough for safe overtaking. The gearing is slightly higher than the 45 at 28mph /1000rpm so, as the tacho is correct, the speedo is 6% optimistic as it read 60 at 2000rpm instead of 56.5mph and 90 at 3000rpm instead of 85.
The BMW 16v dohc, common rail oil burner lacks the punch of my 45: there's none of the L series' strong surge as the revs pass 2000 and it seems reluctant to rev although it does pull smoothly from 1000rpm in any gear.. None of this is a surprise as it is considerably detuned & add in higher gearing and the higher mass of the 75 and its no wonder it just cries out for more fuel to show its mettle. However, plug in my Tu3 or Synergy tuning box and a transformation takes place, releasing the true potential of the engine and endowing the 75 and ZT with the performance it deserves.
On the downside, the clutch is heavy: very heavy in comparison with my 2003 45, which itself has a lighter clutch than its forebears. However, once on the move, it only needs pushing about 1/2way down, feels 'strong' with good bite and is also very progressive. I did notice an increase in engine noise when depressed - I assume its the hose transmitting the noise. Some auto' models are also noisier and need a mod to the selector cable mounting bracket. (Fitment of rubber isolating bushes)
I like the interior - poor mans Jag some say. Very poor mans Jag
the way prices are now that MGR is no more. If you are thinking of changing
your lesser Rover, now's the time to pickup a 75 - from under £4000 on Ebay,
and not much more from dealers or in Autotrader. 
Standard dash below, with upgrade kit - above.
TUNING TARGETS.
My Rover 45 does 40-60 in 4th in 5secs and 50-70 in top in 6.8secs on a nearby level stretch of road using a stopwatch.
My 75 (a 116ps model) did 50-70 on the same stretch (& the same direction) in a pretty ordinary 9.3 secs. (10.5 with maf unplugged)
However, I've transformed the performance with my SYNERGY tuning boxes. It now goes more in keeping with its image as well as showing a clean pair of heels to Mercs and Beemers. Few cars do 50-70 in top in around 7secs or 60-80 in under 8 and still return 44-50mpg.
The BMW M47R 16v chain driven DOHC engine. Made by BMW in Steyr, Austria, it superior to many other diesels, being smooth and quiet, but not as quick to rev as the L series. Probably due to a heavier flywheel. This improves the smoothness but hinders the throttle response somewhat.
Its can also be found in the 115ps Freelanders after '99/'00.
Unlike the version fitted to the 136bhp BMW 320d, it has Bosch common rail fuel injection.
With the cover removed the engine is barely any noisier. The inlet manifold is plastic and the air filter is at the back to the right of and behind the oil filler cap.
I'm not overly impressed by that air duct supplying the air filter. Those corrugated bellows can't be good for a smooth airflow.
The turbo is hard to see, let alone get at except from below and is not a variable geometry type unlike the one fotted to the BMW cars & Freelander TD4.
The Maf sensor - its a Bosch one but has a Pierburgh style connector. So a Pierburgh one will fit straight in, though you will need one of my Mafams with IAT sensors as the Pierburgh doesn't have a compatible one. (MF1P)
The Mafam MF75 is available for the 75/ZT and will improve low down torque and smoothness if your Maf sensor is less than perfect. Use an MF1p if you fit a Pierburgh maf.
Here's a comment from a Mafam MF75 customer...
The EGR valve - see servicing page for cleaning and bypass pipe details
The Exhaust Gas Recirculation valve feeds cooled exhaust gas into the inlet manifold on light throttle and steady speed conditions. This reduces NOx emissions, reduces particulates and minimises fuel consumption.
The ecu uses the MAF signal to control it, since if exhaust gas replaces 'fresh air' the maf signal will drop. The valve is operated by vacuum from the brake servo line and the ecu modulates this via a solenoid valve to regulate the amount of exhaust gas being drawn in.
When the throttle is opened it closes and so in theory it should not affect power delivery.
However, as with the L series, disabling it by simply disconnecting the vacuum tube (& plugging this with a bolt) often improves the throttle response below 2000rpm, giving a bit more torque and quicker response.
It seems to be due to the ecu not closing it immediately when the throttle is opened gradually.
Removing that 8mm braided tube visible in the bottom of the photo disables it.
I have left mine disconnected for the past 5k miles with no detriment.
JUNE 2007 UPDATE - EGR BYPASS - A RECOMMENDED MOD. Checkout EBAY for the suppliers
An egr bypass pipe is now available. It is a direct swap for the original one and improves torque and removes the need to clean it.
TYRES:
This is very much a personal choice, however I recommend a visit to tyretest.com. Here you can read other drivers ratings (lower scores = better!!) and one thing is very apparent, most of the big brands do not do very well on things such as noise and comfort. If these features don't matter to you then that's fine, but they do to me.
So, in the past I have used Vredestein Sportrac's on my 45 with excellent results and am now using Hankook K105 Ultra High Performance tyres (their claim).
These are a mid priced asymetric tyre, have rim protectors (thankfully) and the 215/55x16s cost about £270 a set delivered (in 3 days) from Mytyres.
I am very impressed - having replaced the 195/65x15 Hankook K701 (general purpose & £40 each), I was expecting more noise, a bit harsher ride and a wee bit of tramlining.
Not so, they are quieter than both the Hankook K701s and the Dunlop Sport 01s that I had on the rear. The ride quality overall is unchanged and only slightly firmer on pot holes, though less bouncy. Grip on dry roads of a big step up from the smaller tyres as you would expect and there is less understeer, more precise turn-in and no tendency to follow white lines.
Highly recommended at this price.
Not recommended. Dunlop Sport 01 - are noisier than the even the budget Hankook K701s and little better overall.
CAR MECHANICS MAGAZINES FOR 75 and ZT OWNERS
The editor has kindly sent me several recent issues which I can recommend to all 75 / ZT owners. In the absence of a Haynes manual, these will prove invaluable and should be added to your arsenal of servicing tools.
NOVEMBER 2005 AIRCON FAN REPLACEMENT
DECEMBER 2005 75/ZT CDT CLUTCH CHANGE
JANUARY 2006 GEARBOX REBUILD
FEBRUARY 2006 CDT SERVICE GUIDE
MARCH 2006 BRAKE CHECK, CHANGING MAF SENSOR
APRIL 2006 PETROL ENGINE PROBLEMS
NOVEMBER 2006 TU3 TUNING MODULE REVIEW
FEBRUARY 2007 TU3 FOLLOW UP REPORT.
Back issues are available from the publishers for £3.80 each
MODS: DASH UPGRADE KIT AND FOG LIGHTS - NON ROVER
I bought these Angel Eye copies from an Ebay shop for £25 per pair. They have semi sealed beam lamps and a white led illuminates the out ring via a separate wire.
They measure 9cm in diameter and will just fit through the blanking plate either side of the lower grille. These just unclip if pulled forward on their inboard edge (closest to the centre grille).
Rather than try to make up brackets to bolt the lamp's fixing bracket to, I removed the bracket and made them a firm push fit through the hole I cut in the blanking panel. Then I lined them up on the road one evening and glued them in place with black silicone rubber. This also makes the join with the panel neat and watertight.
The dash upgrade kit made a big difference and was easy to fit. Available from TOC Styling and several other companies such as the Walnut Dash Co. You specify which options you need to match the oem equipment level. E.g. Air con or climate, radio/ Cd or sat nav, 2 or 4 electric windows etc. See below for another photo.
SUGGESTED SUPPLIERS & COMPANIES I HAVE HAD GOOD SERVICE FROM
RIMMER BROS. Official MG Rover parts supplier. Mailorder.
IS HERE