308 differential

Remove the 1-4 exhaust manifold and you can remove the differential cover . Unbolt the half shafts and take out the differential.

 

I can confirm that on '82 308i you can remove the 1-4 header and then remove the differential cover and differential internal. The way I removed it from the chassis was by removing the cats or bypass pipes. Comes out fairly easy.

 

Is it possible to change the gearing in the diff on a 208 GT4? Trying to make the overall gearing less high revving.

 

Compare the ratios of the various V8s GT4, 308,329. Changing the differential ratio would be a lot of work and expensive. The main shaft of the transmission is the pinion gear. The transfer gears by the clutch were made in different ratios for the different models. Those are super easy to change. Look into the ratio of those for a base version and a US version of those. I suspect a US version 328 will have the highest ratio of the transfer gears but thats just a guess.

 

I believe it is physically possible, but you'll have two issues (assuming that you can get the parts):

1. Unlike this discussion about just rebuilding the differential (which has only the crown gear), you'd need to replace both the pinion gear and the crown gear = this requires disassembling the gearbox as well so much more labor cost, and, maybe more importantly,

2. They went to the high revving gearing (15/69 diff) because the (non-turbo) 2.0L just doesn't have the low end torque of the (non-turbo) 3.0L. Even on the first turbo 208 they still went a little higher revving with a 16/69 diff. They didn't go to the 3.0L 17/63 diff until the later turbo 2.0L models. Maybe you could live with the 16/69 diff if you were willing to live with less low end acceleration, but to use the 17/63 diff like the 3.0L models you'd probably need to add engine power.

 

Thanks for entertaining the idea gents, I'm convinced it will work. The car has plenty of torque on the road regardless of what the specs say, it pulls strongly above 2500. My goal is to take the motor from revving at 5000rpm at 90 mph down to say 4000, which is still nicely within its torque band.

 

As per other thread live with it for a year .

 

The real fix is to get a 328. Its pretty happy at a 100 or more cruise.

 

Thanks again gents, having lived with it for two more days I'm going to let it be, why mess with such a great thing.