I have been thinking about on thing and since many guys around here know their way around those engines they might give their input.
Just to be clear. I am not thinking about doing it, but just would want to know.
What is would the difference be between those two?
Supercharged and turbocharged.
Benefits and drawbacks. This might be a fun discussion.
From what I've seen, I would think supercharging is more parasitic to engine output. Isn't that right?
Supercharger is a compressor that runs off a belt driven by the crank pulley
Turbocharger is a compressor that is driven by exhaust pressure.
fitting either into the engine bay of an 850 is a challenge. if you turbocharge you would need 2 to do it properly. You could get away with only 1 supercharger.
Current:
- 09 335i MSport, FBO.
- 98 Euro M3, Estoril Blue
- 04 M3, Carbon Black, 6 Speed Coupe
- 06 M5, Black on Black, Full Leather.
- 73 3.0CS, Tagia Green, 5 speed M30b35 converted
Ex's: 1984 325e, 1988 325IX, 1992 525I, 1995 540i/6, 2002 330i, 2005 330xi, 1992 850i, 2003 330i #1, 2003 330i #2, 2002 330ci, 2004 330ci, 2007 328CI, 2007 335i, 2001 M3, 2006 M5 6 speed
Good details to come on this topic. We just had a great presentation on the subject. I'll talk to Brian and see if we can get a link to the presentation uploaded.
Jeremy Smith
94 840Ci
98 Porsche 986
02 Mini Cooper
13 Ford F150 Platinum
Bryson, please pick up the nearest white courtesy telephone.
lol
The benefits of a S/C over turbo are mostly packaging, decreased system complexity, immediacy of power delivery and cost
The benefit of a turbo (or two) over a S/C is power. A mildly tweaked m70 with a big turbo or two and good engine management should be capable of near 1000hp.
- A single turbo will require use of a standalone engine controller to avoid engine damage/failure in the case of single bank shutdown
- Twin turbos have very limited packaging constraints due to the giant steering box on the driver's side
- Twin twin-scroll turbos could make for very quick throttle response while still being able to hit the 550+hp pump gas daily driver (this is what I have sitting in a box and designed in-part on my computer)
So your limitations are really; How much power do you want and how much are you willing to spend to get it? If you want less than 550hp, buy John's S/C kit and ask for the big C38-91 blower. If you crave more than that, go turbo - you can throw some money at me and hit me up for system design
that's pretty much it in a nutshell
Last edited by Bryson; 10-06-2013 at 10:58 PM.
2.8 Z3 coupe + 6 speed || 200kW electric 1970 Jaguar XJ6
If you were to get rid of the steering box, would that open up the design space significantly or does the volume constraint shift to the other side?
I was thinking that it might be possible to replace the steering box and hydraulic power steering components with an electric rack "fly-by-wire" system.
I would love a twin scroll for my 850. Do you have just the design or a "working model"?
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Also how would the stock auto trans handle this kind of power?
1983 Monte Carlo SS
1984 Pontiac fiero SE
1993 BMW 850CI
1994 BMW 525I
There was a supercharged 850 at 8-Fest that is veeeery fast and it works. Designing one of these in a computer modeling program might give you a 3D picture of the components, but there are a lot more real-world parameters that need to be considered besides just seeing if the parts fit. Having seen both the DINAN TT and the single S/C 850, and having driven the TT and watched the S/C blow by at Warp-9!, either way will work, and produce more than enough power to put you over 200mph.
As far as being able to attain 1,000HP from the M70 with a TT, you need at least double-digit boost. The DINAN TT Stage 3 car manages 625HP running around 11-12 pounds of boost. To get to 1,000HP, you will need to crank the boost up much higher than that plus use some "special" fuel. The M70 really might not do too well with 20 pounds of boost. The Stage 3 uses a modified engine to get to its 625 - forged pistons, crank, etc. The 1,000 HP dream is just that -a dream...
Besides, the S/C looks like a beast and sounds as mean as it looks! 1,000HP might be everyone's wet-dream, but the reality is that your tires won't be able to keep up - at that point it is worthless...
'93 850Ci - Mineralweiß Metallic
2001 740iL - Titansilber
ALPINA B7 -Alpinweiß III
...the price of cool ain't cheap!
I'll happily take a s/c kit.
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But really, where can I get either a s/c kit or a turbo kit, preferably s/c.
I was told to contact johnindc but he never got back to me.
1983 Monte Carlo SS
1984 Pontiac fiero SE
1993 BMW 850CI
1994 BMW 525I
If you have an M70, and want a supercharger, then John is your guy. Very nice quality work.
'93 850Ci - Mineralweiß Metallic
2001 740iL - Titansilber
ALPINA B7 -Alpinweiß III
...the price of cool ain't cheap!
are there any actual pics of Johns kit how it looks under the hood?
For the record, I absolutely recommend the supercharger setup for 98% of owners! Definitely give John a ring, I wouldn't consider anything else an option really
2.8 Z3 coupe + 6 speed || 200kW electric 1970 Jaguar XJ6
Well, you did consider the turbo
Hello Larkin,
i have the stage |||+ from John ,
installed the day before the fest,we then drove from Los Gatos to garberville with a flawless run and return back home.
John estimates 530+ and 480 hp at rear wheels, with room for improvements from there.
i will be changing the diff gearing for even more improvements.
the installation is very clean and almost unnoticeable from above.
John is a perfectionist and it shows.
he will fly to your location and do the install and final tune for a nominal fee.
Brave.
Do you have a pic of the kit installed?
In for Pics......
Bave- automatic of manual?
Thx
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