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[jimmytractorboy]

Hi,
This is my first post so please go easy on me if I've done anything wrong! Hope this is the correct place to post this query. Also, I did try a search first but couldn't find much relating to the diffs on the diesels.

Doing a few upgrades on my 2.5 bmw diesel omega and would like to increase the gear ratios a bit as it is so low geared as it is. Are there any fairly cheap and easy diff upgrades or gearbox upgrades which would increase the gearing a bit?

Thanks in advance,
James

[TheBoy]

From memory, the TD is 3.7 diff, which is the highest geared on there is

[Shackeng]

I am somewhat puzzled by this post, as I have never felt that my TD was too low geared. Wrongly programmed to suit the auto box perhaps, but this is easily resolved by chipping and using sports mode on country roads.

[Diamond Black Geezer]

You want to be looking at

a. Chipping the engine to release the power and torque that BMW designed into it in the first place, before GM decided to detune it for whatever the hell reason.
b. Fitting an AR35 gearbox from a 3 / 3.2 litre Omega - due to the increased risk of 'box damage, from the increased power (see a.)
c. Gearbox software update - may or may not make much fo a difference - but as they say 'can't hurt'

Several of the above services are available from various OOFers, including the good Mr The Boy, above. 



While I'm here - a teensy mini-hijack - what are the effects of fitting the TD diff into a '96 V6, please? - increased acceleration, but would it be doing 3k rpm at 65mph or something daft?

[jimmytractorboy]

Sorry, I should have mentioned that it is a 5 speed manual not an auto.

[Diamond Black Geezer]

Ah no worries, as far as I'm aware the manual is strong enough to withstand the extra oomph from chipping/remap, but happy to be corrected. To be honest as so many Omegas are Auto I can't remember the last time someone chipped a TD manual, to be honest, hence my being unsure.

[jimmytractorboy]

Cheers guys

Yea I've been doing quite a bit of research and the general consensus seems to be the manual box is well engineered and very strong so should cope fine with any power increase i can get out of it. Just glad its not the auto box as from what ive read it can barely cope with the standard power! Maybe why they tuned the 2.5 down so much in them?

I've been researching a way of increasing the gear ratios but no luck with that unfortunately. It may as well be a 4 speed box as unladen you can easily pull off in 2nd without slipping the clutch excessively! And 5th is far too low on the motorway unless you cruise at 65, want to be able to cruise at 80 with fairly low revs

I am planning on getting it remapped but not sure where to go. Who are the best at mapping these? Is it true they cant be flashed via OBD and you physically have to change the microchip inside the ecu?

[05omegav6]

Indeed, chip away

Remember,  the clutch is only 23 bolts and two spring clips to change

[TheBoy]

Non (in-situ) flashable on these, you have to unplug (earlier) or unsolder (later) the map chip and replace.