blunt question

I would have thought it cheaper to supercharge or turbo than the hassle of manual conversion.... IMHO

A Euro 4-speed auto, with a stock 3.15 diff will do 0-100 in 7.4 seconds.
6-speed manual with a stock 2.93 diff will do it in 6.8 seconds.
A stock CSi same diff will do it in 6.0 seconds.
The CSi has 80hp and 100nm of torque more than the 850i.

In comparison, the 350hp Alpina 5.0 auto with a 3.45 diff does it in 6.8 seconds.
That has 50hp and 25-30nm more torque than a standard 5.0.

The Alpina hp is roughly what you can expect from camshafts and chips.
the 3.91 diff should shave off another 0.3 seconds or so, making 6.5 seconds possible with an automatic.

Given that these cars are a bit old, you would expect them to have lost some power, and there is a little wear here and there and will probably not meet these initial figures.

One thing you would find with a 6-speed and a 3.91 diff is that you would shift a lot, and to get to 100 you will have to shift to 3rd gear.
I would not do it.

My car has a stock M70 plus my chip set and a 3.64 diff. unit.
Using a GPS smartphone app I measured 6.5sec several times.

I think the ALPINA B12 5.0 suffers from the slow throttle response. Engine power wise it could do better IMO.

I have Wokke chips Mk1, 3.91 diff, K+N filters and get 6.5 in sport mode.

Happy with that as it gives a few modern lighter cars a run for their money...

What you are proposing is actually pretty much a 5.0CSi and that will not do the 0-60 in 6 seconds unless you make a lot more power or a lot less weight.

Forced induction is your only way to get there if you wish to keep the car roadworthy.

8Tech.

Zitat von 8Tech;100705

What you are proposing is actually pretty much a 5.0CSi and that will not do the 0-60 in 6 seconds unless you make a lot more power or a lot less weight.

Forced induction is your only way to get there if you wish to keep the car roadworthy.

8Tech.

Not quite.

He is talking about a 350hp/475nm 5.0 6-speed with a 3.91 diff.
Given that the CSi has a 2.93 diff he might make 6 seconds, but he has to shift a lot.

But I agree that F/I is the way to go to get a significant performance boost.

What about Nitrous Gerry? Would the auto box take it? I know they are rated around the 400bhp mark!!

Zitat von schnitz850;100708

What about Nitrous Gerry? Would the auto box take it? I know they are rated around the 400bhp mark!!

The 4 speed auto can handle 600hp, I think you would start to worry around 7-800hp.

Mine was reinforced and should have no issue with well above 600hp.

Try to look for Schrick cams on google.

Your Wokke chips will probably not work perfect with those, so you need new chips, if you can't get a kit, you may need to custom tune to get the most power.

This will get you about 350hp, but the price may not be worth it.

http://store.vacmotorsports.co…0-camshaft-set-p1113.aspx

Looks like M20 cams are about $500 each, and you need two of those.

Zitat von KMS;100767

so you mean go back to the original chip set, or a special set?

custom made special set if you change the hardware on the engine.