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CSL Register Uber-poster!
Join Date: Jun 2008
Posts: 4,247
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looks like a good upgrade !
Quote:
EXHAUSTS
-Long gone are the days when a performance rear exhaust would seriously boost power output; factory cars are generaly so well designed these days. To get the most out of a new exhaust it is important to choose carefully, as so many are “built to formula” ( ie a certain size box for a certain size engine, with generic internal muffling laid out in the same way for each model) ; they may sound nice but normally offer zero or little power gain ( in some cases power loss even) . Many so – called “custom” exhausts are built this way too. A true custom, performance- gaining exhaust is designed for each specific vehicle application from the ground up, then tested,adjusted, then tested again,adjusted again and so on until the best balance between sound and power is achieved.
-It is also important to bear in mind that quite a few so called “Stainless” exhausts on the market actually have mild steel internals! As approx ½ pint of water is produced for every gallon of petrol consumed by the engine (that’s actually where most of the water you see coming out of the exhaust in the morining is from, not atmospheric condensation as generally believed) , exhausts tend to rot from the inside, so internal structure is very important for longevity.
-Exhaust manufacturers that in our experience meet the right criteria include : Tubi style, Eisenmannn, Larini, Supersprint. All these should see a gain of around 4 – 7 bhp on an E46 M3.
-Also bear in mind when buying a branded tuner exhaust, these are usually made by a mail line manufcaturer anyway ( eg Hamann = Supersprint, AC Schnitzer = Remus, AMG, Brabus, Mclaren, Alpina, G Power, DigiTec etc = Eisenmann) so unless the actual badge on the exhaust is of paramount importance to you then you can often get the same exhaust for less money by going direct to source. REAR SPORT MUFFLER VALUE RATING... 3-4
-Centre sections do not offer much other than sound, but a decat pipe or sport cats will...with the right mapping. Good sports cats tend to be expensive ( we suggest opting for platinum / metalic variety, more efficient and longer lasting than cheaper ceramic type). Whilst a decat pipe offers pretty good value for the power than can be gained, the more expensive metallic sport cats not so much, so we normally leave these as one of the last tuning mods. VALUE RATING DECAT PIPE... 3-4 VALUE RATING SPORT CAT... 2-3
-Most good aftermarket exhausts are also lighter than the OE parts, adding to the objective performance gain.
-Titanium exhausts made so popular years ago by Gruppe M have their niche market placement, their high cost putting many off. There can also be problems with Ti depending on grade and quality of welding...good Ti alloy will anneal ( get harder and stronger) over time as it heats up and cools down with use...but this is not always the case; also Ti must be welded in a completely oxygen free environment, which can be difficult to achieve, the result being fractured or seperated welds after a few thousand miles use. It seems to us the only Ti exhaust on the market that is worth considering is Acrapovitch, if their motorbike exhaust are anything to go by. However only you can decide if the weight saving is worth the cost. As a general rule of thumb, losing 5 – 7 kg of a car is the rough equivalent of gaining 1 bhp. Being made from Ti per- se does not make a Ti exhaust more powerful than it’s stainless counterpart of course, this is still all down to internal structure etc.TI EXHAUST VALUE RATING ...OPEN TO OPINION
-Headers/ manifolds can be a bit trickier to evaluate as to power gains and value, as their effectiveness depends on the rest of the engine spec. As a general rule of thumb, they are not so valuable on a supercharged car ( cylinder boost pressures tend to overcome most of the advantages of headers as they force the exhaust gasses out anyway) but on a well tuned naturally aspirated engine they can add power, albeit normally at the very top end, with a comensurate loss in low end torque. Depending on application ... HEADERS VALUE RATING... 2- 3
UNDERDRIVE PULLEYS
One of the oldest tuning tricks in the book, and rare in that there is no real downside. There is no doubt whatever that these work, laws of physics and all that, as the engine fluid pumps are not drawing as much engine power then more power arrives at the driven wheels. The car also revs better. Evopsport are our pulleys of choice, expect around + 5 bhp and more response for around £180.00 VALUE RATING... 4-5
REMAPPING
What a minefield this can be ! Such a load of hyperbole and exagerations out there. At the end of the day laws of physics and chemistry prevail, and all GOOD software engineers will get almost identical power gains, how can they not considering they are all doing the same thing....adjusting fuel and ignition values ( the better ones also re phase the vanos) within accepted levels of safety until best power is achieved. So for one tuner to claim say 7 bhp more than another of equal standing is generally just not a substainable claim.
Most copmpanies can offer generic “off the shelf” maps ( fine for standard and mildly tuuned cars) as well as customised maps for highly tuned cars.
A remap is almost always a good idea, eliminates flat spots and speed limiters and adds response and power, without taxing the engine. 12-15 bhp is the absolute maximum gain on a standard M3. VALUE RATING...4 -5
CAMSHAFTS
These also work very well, but go too wild and tractability and steady idle can suffer badly. Expect around + 12-15 again on a stock M3, with harder mid range punch and eleveated rev ceiling, say another 200-250 rpm. At a typical fitted cost or around £1500.00 this carries a pretty low VALUE RATING... 2
SUPERCHARGING
For value, nothing else comes close if you can live with the initial high kit cost ...for example £40 / bhp for ESS CFR 550 system !! Install they kit properly and look after the car and it will last you an age with very few problems...our own 540 bhp M3 s/c has been running for about 4 years and 65000 mls ( most of this hard use at tracks at drag strips) with very few problems, and still makes the driver smile from ear to ear. VALUE RATING... 5
STROKER KITS
Fancy a 3.4 or even 3.5 litre M3 ? It can be done, and provides significant increase in bhp AND torque, whist techinically still keeping the engine “unstressed”. The car does tend to rev slower (due to longer throw on the crank), but is somewhat compensated for by the extra torque all round. Expect around +45 – 70 bhp depending .....VALUE RATING 2
WEIGHT SAVING
As Lotus designer Colin Chapman said “for speed add lightness! “.You will be surprised what a difference shedding a kilos off your chassis can make to performance and handling ( think how different the car feels with an almost empty fuel tank vs a full one). This can be achieved in a number of ways such as lighter seats , carbon fibre panels, thinner glass, removing rear seats etc. Difficult to put a value on this one, as so many variables, but would say an average of ...2-3.
SUSPENSION AND BRAKES
“Eh ??” I can hear some of you say... many do not realise just how much quicker a car can be point to point with uprated brakes and suspension fitted. You can corner faster and brake later, so elapsed journey times will be shorter, more fun and above all SAFER. Although there are many cost options and levels, this combination in our opinion gives these kind of upgrades VALUE RATING... 3-4.
INTAKE SYSTEMS
Another somewhat controversial subject.....again cars are so well designed these days that huge gains from an intake system are rare ( the exception being CSL style airboxes, more on this below).
The M3 uses a “pulse tuned” intake which relies on the intake tract being semi – pressurised at speed ( hence the air scoop at front of bonnet) so it is particulary effective and hard to improve on. Having said this we have seen up to 7 bhp increase with the Gruppe M and Carbonio intakes, which are essentially a slightly enlarged and more free flowing version of the OE intake. Gruppe M used to claim + 18 bhp increase fro their intake ....no how no way, not never !
Some years ago we actually noticed there was a small problem with the Gruppe M intake in that the velocity stack ( the tubular part that houses the air mass meter or MAF) was some 1.5 – 2mm smaller diameter than on the OE intake, which is a big NO - NO because the air meter is carefully designed to provide accurate samplings to the DME within very specific parameters, two of these parameters being its position within the velocity stack and the stack’s diameter...change these and chances are the effects on engine smoothness and power will be detrimental. This applies to ANY intake system that involves any alteration or re positioning of the MAF. After speaking to Carbonio about the same problem they took the step of rectifying this on their intake, this is why along with the lesser cost, we recommend the carbonio over the Gruppe M ( although we sell both ). We believe Gruppe M followed suit soon after.
As a general rule of thumb, if you can see the filter of an intake system once it is fitted, then it will lose power, as once the engine warms up the filter will injest hot air which is less dense than cold, so the DME will cut back fuelling and hey presto – less power. Owners often dispute this saying things like “but I can definatelly feel a difference in the way the engine pulls...” which is absolutely correct, as often the new intake system will alter the way power is delivered ( the dyo curve will be a different parabolic shape) so even though less power is being produced the car does indeed feel different, and this differenec is perceived by the driver as a power increase. However, encase the filter or provide a fully enclosed heat shield and things will improve improve. Having said this, chances are that the classical open filer and heat shield type of intake will always lose power on the M3 because you have completely taken away the “pulse tuned” effect as the system is no longer sealed and semi – pressurising.
So in conclusion...use the Gruppe M / Carbonio style intake or none at all ( unless induction noise and not power is your priority) VALUE RATING 2- 3.
Carbon – Airboxes ...a good, correctly functioning one can give around +30 bhp or more as we have shown time and again with independent tests by our customers ( dyno charts etc can be viewed on our website). The internnal structure, funelling and air seperator rods are what make or break a carbon airbox...choose a cheap one and it may well look and sound nice but may not give you much gain. A big problem with many cheaper aftermarket ones is that the intake tract of the airbox ( where an external air filter, if used, would be fitted) is below the level of the throttle bodies, which can alter the dynamics of the airflow to such an extent as to cause flat spots and lesser power etc. The best ones are those that copy the OE CSL design ( after all BMW spend tens of thousands of Euros developing it) as closelly as possible. This type is comparatively expensive...but it works. VALUE RATING ( based on good quality CSL copy) 3
ENLARGED THROTTLE BODIES
Many owners are unaware such a thing exists
Fit them on their own and you can expect around + 4 – 7 bhp with harder mid range punch, depending on condition of engine, but they are just as useful if not more so when combined with other mods such as intake, cams etc. Due the the expense though the value rating is low VALUE RATING 2
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03-11-2010, 02:46 PM
Hybrid Mode
