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Old 12-10-2008, 01:58 AM   #6
Nik@vf-engineering
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Join Date: Jun 2004
Location: California
Posts: 173
My Ride: '03 540i sport 6spd
*** UPDATE ***

As correctly pointed out on another forum, this was not what most enthusiasts would refer to as an "engine build". The thread title could have been worded differently. Well, many here already know some of the details, but here is a concise write up:


Objective
To increase engine power output by lowering engine compression ratio and increasing duty cycle of VF-Engineering stage 2 supercharger. This new power level would be called "stage 3". The goal is to keep cost as low as possible and retain engine reliability with as little knock correction as possible on 91 octane.

Apparatus (Test car)
2005 ZCP SMG. Installed with VF-Engineering Stg2+ (T-trim). Supersprint headers, high performance cats and exhaust system, upgraded clutch and water injection for the summer. Currently producing 500rwhp on 91 octane.

Background of test car owner
Many of you know him already- Drew aka DLSJ5. Drew is not affiliated with VF-Engineering. He is a die-hard enthusiast who pushes the limits of his car. His signature being - the stock appearance of his car with his son - Jake's car seat locked in tighly in the back seat. Jake (just turned 4years old) will tell you without a flinch what his daddys favorite car is. He can also tell you what the best car in the world is. And that is the "Supercharged M3".

Method
Many tuners have successfully lowered the compression ratio by spacing the cylinder using a "shim" as a production solution. VF-Engineers chose to try this method in order to keep costs to a minimum and give enthusiasts a minimally invasive modification yet take power up another notch. The usual formula of 0.040" per compression point was used to create a cumulative head gasket "stack height" of 0.070" using OEM gaskets to sandwich a lazer cut stainless steel shim.

BMW OEM tools to remove and replace the cylinder head were pre-ordered (took 2 months to arrive) and OEM instuction manuals obtained through "friends". Separate tools were required for removing vanos and cams and for installing them - per OEM procedures. All-in-all 4 months of prep went into the project leading upto today.

Results
Prior to removing the cylinder head, compression results were 170,170,165,163,170,170 which was right inside the factory spec.

The head was removed and pistons and valves examined as the vehicle had been running with the stage2 since the product was released. Pistons and Valves were found to be extremely clean (thanks to the water injection quite likely), and no pits or scarring were evident at all. Gaskets were installed and head put back down (lots of details omitted). Finally when it came to putting the chain back on the cam sprockets it was determined that there was insufficient chain length to allow for the thicker head gasket. Various options were explored and our main engineer chose not to pursue this avenue any further due to engineering principals. As with all research and development we experience many highs and lows. This result was not completely unexpected as we started this project as an "unknown" and expectations were not being set until achieved an end result.

Summary
The head gasket spacer was removed and the head re-installed per OEM factory procudure and this method of lowering the compression was struck off.

Conclusion
Our engineers chose to keep the stage 3 option available for anyone choosing to install upgraded rods and low compression pistons. An example of this being the Evosport Stg4 car featured earlier this year in European Car Magazine which produces 600whp on race gas. Having been given the above information, two forum enthusiasts have since chosen to go down this route of upgrading rods and pistons already. They will update you when they have more information very likely. It will off course be more time consuming.

DLSJ5's comment
"Nik, I absolutely loved what you did for my E46M and you guys support your product and our community so much, thankyou. It is time for me to move on and upgrade my car as I normally do every couple of years. "

Jakes comment
"daddy lets get another M3!"
DLSJ5 will probably drop in with some words and a hint of what he is planning next.

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