BMW 850

Gransin

Gransin

Well-Known Member
Site Donor
Messages
1,529
Reaction score
1,273
Location
Vasa, Finland
Nice! I’ve seen and heard that the V12 is quite safe to boost, and very responsive as well.
There was a stock bottom-end TT 750i in Sweden some years ago, the tourqe in that engine was crazy.
Post some dyno figures later if ever put it on a dyno:)
 
Belgiumbarry

Belgiumbarry

Well-Known Member
Messages
1,618
Reaction score
1,117
Location
Belgium
Yes , it's a supercharger Raptor V .... indeed those V12's are safe to boost as they have OEM a very low compression , not even 9 to 1. I bought that 850 end 2016 as it was in good condition , only 140K kilometers , color was my taste , black on black , and manual !
After some repairs ( sticking brakes , needed new master and problems with air metering , new wheels/tires etc... ) my goal was a supercharger. Soon on the dyno ! ( normaly we should go to 450 HP , above needs bigger injectors)

The nicest BMW ever made ? nonono , that's the CS !! :D

850 006.JPG

Mpars 005.JPG
 
Belgiumbarry

Belgiumbarry

Well-Known Member
Messages
1,618
Reaction score
1,117
Location
Belgium
a short update... the story became a little nightmare. Problems with tuning finally revealed 2 ( 3 ) bad injectors.... so we placed new ( bigger) injectors , also cleaned the tank and new filters.... This is a nice upgrade as the stock injectors are limited to "450 HP" ... now we are prepared if we want to go higher PSI with smaller pulley .... also injection time is better and not nearly 100% .... we could increase the fuel pressure but that changes the spray pattern...

But the problem wasn't solved completely , much better but still some misfires at high revs.... so we think now ignition related.
Tomorrow we change rotors,caps and wires ... and hope for final good results !

It looks modern , but is also 25 years old..... and pieces are expensive ! Just to warn candidates , yes , you can buy one for 20k .... but than it begins.... most of those cars are also 5..10..15 years sitting somewhere ... without maintenance. :(
the ones with maintenance have on the other side mostly 300k kilometers...
 
teahead

teahead

aka "Rob"
Site Donor $
Messages
6,392
Reaction score
1,848
Location
Tacoma, WA, USA
Takes some cajones to not only own an E31, but to also mod one as much as you are.

It's only money and time, right?
 
Belgiumbarry

Belgiumbarry

Well-Known Member
Messages
1,618
Reaction score
1,117
Location
Belgium
yeah Rob, money & time :) but a nice hobby ! and i like to have always something on my mind , how this, how that....
The 850 was bought with the charger build purpose....OEM it's just a heavy cruiser with 300HP....nice car but no "wow"...
It started as a local forum "bet" that i could build a better allround oldtimer than a Porsche 964 for half the money ,
it's more the BMW guys against the Porsche ones....:D
Remember here in Belgium a car is oldtimer once 25 years old... little to no taxes and cheap insurance. Last year they changed it to 30 years but the previous registrated "oldtimers" stayed oldtimer. So does my '91 850....

New ignition test is for today , BMW dealer had yesterday 2 caps,2 rotors and... 1 set wires :rolleyes: within a few hours i can collect the second set .
We are not pushing limits, goal is the 450 HP , to keep it safe. That's already 1.5 times OEM... with the stock internals.
We opted for a intercooler ( instead of water injection) as less maintenance for a seldom used car.... now we see some pressure drop over the cooler , so think we will end between 400 and 450... but cooling the air has also a positive effect.... very curious were we will end. Smaller pulley and remap can ofcourse help that but want to drive the car this summer in the setup we have now. Don't think it makes much difference if we have 430 or 460... it's not a race car.
 
You must log in or register to reply here.
Top