Anyone chipped their 850?

Rob,

Do a search using the button in the upper right taskbar. You'll find possitive info on chipping your 850 (say 37 bhp, and 80 nm torque).

Cheers,

Peter

Hi Rob. sorry to not reply earlier.

I have chipped and installed a 3.91LSD and WOW what a difference. I haven't had the chance to do a Dyno (we must organise one as a group thing) but bang for your buck is pretty good.

I got my chips from wokke_2000 on ebay. £135 ish buy it now for 3 chips...

http://search.ebay.co.uk/_W0QQ…rppZ25QQsassZwokkeQ5f2000

and the diff was an ebay purchase £125.00 ish.

E34 M5 diff I think.

Hope this helps....

Is that a slippy diffy or non slippy diffy?

If you swaped tem then your wife would like her better fuel economy and therefore save you her speeding fines although you would have a big grin on your face from the 3.91 non slippy diffy I fear the speeding fine would be transferable with the diff.

The 2 things that are different are the input flange (which just pops off an back on again) and the rear cover.

The chips (3) made a difference to mine because not only do they alter the way the engine runs they extend the rev limits I think and remove the 155mph limit....

Hope this helps Rob.... give me a call on 07973 735 793 if you want to chat....

Not that matters for road going cars , but the Max 155mph will never again be seen with a 3.91 diff.

I estimate my top speed would be around 140mph with my 3.91 ,but dont worry the extra excelleration is a worthy sacrifice

Chipped feedback

Met up with a mate at Gaydon last week and he couldn't wait to show me his rear end on the Aston Martin Test track since he had had his 850 fully chipped. The short and long of it was that he couldn't stay with me. My 850 is standard but with the cats removed following a stainless powerflow exhaust installation some years ago. We spoke to the guys at Thorney Motorsport while we were there and they reckoned that the cat removal probably achieved better results than the chips. I think he was a bit gutted but I was certainly surprised. I went to a talk at Gaydon on engine management remapping and was quite impressed. They also talked quite a lot about fuel grades and are currently doing some extensive testing in this area. It seems to be coming out that Tesco 99 octane is producing the best results.

All good fun and by the way the Aston Test track was brilliant.

I recently fitted chips to my 850,yes there is an improvement,but not so much to the power but the gear shifts, kickdown a lot quicker that previous,I think its a strange engine for tuning purposes,its been designed for high speed crusing,there is a lot of power but no where near what it should put out for the size and design, I find the power delivery feels almost linear regardless of rpm,so I conclude the cam profiles are too mild(done for economy) and the throttle bodies too small for the same reason,and the exhaust too restrictive again economy,intake manifold looks well designed with long intakes but there is for sure some airflow restriction holding back the power,I suspect removing the restrictions will yield lots more ooomph,and gearing changes be unnecessary (I like the low rpm cruising)but fuel consumption will be massive I am thinking 11 mpg!!!! does anyone have listed the CSI differences? it may be worth seeing what the factoty did to improve performance and improve on their changes,---bugger the fuel

I think fuel consumption was improved with the cat removal. I rarely get less or more than 20mpg with the daily commute but on a decent run at average 85mph I get about 24-26mpg. I am convinced that it would be nearer 30mpg if you did a cross europe cruise. I am considering a 3rd car for daily commuting because I am just adding miles and burning fuel for very little enjoyment.

The CSi has the same intake manifolds, throttle assemblies and air filters etc. The compression ratio is increased slightly, due to the longer stroke, but the main difference, as you've guessed, is a different profile on the cams with wider opening on the valves. Also, the exhaust has a larger bore and different rear boxes. Additionally, don't forget the CSi is a 5.6 litre engine, with lighter pistons and a slightly higher (variable) rev range. (Not sure if the crankshaft is also stronger?) So, there is a bit of difference from the 5-litre engine but maybe less so from the later 5.4 litre engine. ....And yes, you can see the fuel gauge move on the CSi. The CSi engine has officially 380 BHP (DIN), but BMW's new 6-litre V12 incorporating Valvtronic, direct fuel injection and dual, Bi-VANOS on 4-valve heads manages 440 BHP- a relatively small improvement for 10-15 years of newer technology.

thanks for that Arnie,the CSI only has a 15-20% hike in power,still not that great for such an engine,and mainly done on cams,380 should require just shy of 600 cfm air flow ,the throttle bodies and air filters seem a bit marginal at that sort of power has anyone tried enlarging these?has anyone tried larger valves?sorry for all the questions but it does save me research time and give me some direction in which way to go for tuning

There have been attempts to modify the air flow by guys in the States but concluded that its very difficult to improve the stock system

The "problem" in modifying the throttle valves is that they are electronically controlled through the actuator on the assembly and so messing with this would not be easy. This was quite new technology at the time and probably BMW did not want to have a different part, with a larger bore, just for the CSi. This would probably also affect the mass-flow sensors, but the larger ones from the 840 could be fitted here. However, as Steve mentioned, with regards to intake boxes and plenums, no one has really managed to improve on the performance of the stock items. Nevertheless, the new BMW V12 have much larger intake bores and tubing (about the diameter of that on the 840, but of course, two sets.) BTW, how did you work out 600cfm? Does that take into account the engine efficiency (perhaps 20-25%)?

Additionally, the B12-5.7 manages 416BHP, but I think this increase over the CSi is achieved mainly from flowed exhaust manifolds (replacing the cast-iron ones). However the intake plenum, after the throttle (same throttles) has a slightly larger cross-section too, and it looks as if it may have smoothened (honed) ports. There is a US company which does offer ported manifolds, but they are quite pricy and you can probably have your existing ones extrude honed for not too much (next time you take them off to check the banjo bolts...).

Thanks for the info guys, the throttle bodies I can get done , despite the electrical actuation I already do the bmw mini throttle bodies which are motorised (drive by wire) the butterfly we get made by spark eroding , I will have to get one off and measure to see how much can be gained or if the 840 ones are a better option,the air induction system is pretty good to start with so maybe just a size increase and an extra source of cold air feed, its the making it look pretty is the problem and the noise generated.
It may be an option just (JUST!) to fit 2 more throttles,but thanks for the input - its time to get on the spanners and see what is possible/practical I will let you know