840Ci de-restricted/BHP...anyone know please?

[Blue Tuscan]

Hello

Fellow owners

I have an 840Ci sport with the 4.4 V8 engine.

I want to know if anyone has had their 840Ci De-restricted, If so then what sort of top speed/ Bhp inprovement did you get?


Cheers...

[sniff diesel]

Blue Tuscan said:

Hello

Fellow owners

I have an 840Ci sport with the 4.4 V8 engine.

I want to know if anyone has had their 840Ci De-restricted, If so then what sort of top speed/ Bhp inprovement did you get?


Cheers...

I knew they were limited to 155mph but doubt they'd do much more TBH - maybe 160? Didn't realise the power was restricted.

[Job38]

I know Wayne Blackwell on here who has an immaculate 840Ci Sport had the engine and gearbox re-mapped by Gerry (8tech) of Phoenix Motorsports, with good results I understand. Give them a call, TOP BMW mechanics.

[wayneblackwell]

Yes I've had my 8 remapped, bhp on a dyno was 299.9 which I was well impressed with but not only did it improve bhp, torque & mpg it improved the throttle response alot which was one of the main reasons why I wanted it done, I've not had the limiter removed, afterall when do you really have the chance to drive at those kind of speeds?
I can't really see it doing alot over 155, maybe an extra 10mph or so.

[MitchT]

An 850CSi does getting-on for 190mph when it has been de-limited, from what I've heard. Not sure what you'd get from an 840 though. It's probably worthy of mention that an E36 M3 Evo will do about 175mph when de-limited. It has a theoretical V-max of 207mph, according to its gearing, but to achieve this it would need an extra 400bhp to overcome the wind-resistance!!!

[TheEnd]

About 300 is right for these, getting the gearbox remapped too is quite a fancy trick, pretty rare, but it adjusts the gear change points, and often the torque convertor lock up too (ie tell the missus it makes it more economical )

both the 4.0 and 4.4 litre were listed at 286ps, which was one of BMW's favorite "target" powers (look through the figures and you'll see many BMW's were rated at 286)
The extra .4 of a litre was hidden, in a similar way to the 323 being a 2.5.
the 4.4 is the better engine, no bore wear problems, and the .4 can be felt as more torque at lower engine speeds, and more drivable car.
As a result of the targeted output, the 4.4 will have been restricted in a way, to match the previous 4.0, but to really release the extra power would need custom breathing mods which i don't think are available.

300bhp from the torquey engine and a more "focused" autobox would transform the feel of the car.
The ultimare 'box mod would be to use Alpina's switchtronic system, a custom programmed gearbox ecu with paddle switches (or a switchtronic wheel) which uses the autobox as fitted.