:: Detailed G60 Tuning Guide ::
[Note, this is the SECOND part of a detailed printable guide - click here for part one - G60 Engine advice]
Right, hopefully by now your G60 is in fine fettle and ready for some serious tuning…
First place to start (as always) is breathing. Fit a cone filter or aftermarket cotton gauze filter, which on their own won't make much difference but is essential before further modification occurs.
Next you can go for a decent aftermarket exhaust. Milltek and Powerflow seem to be the exhausts of choice at the moment but ask around at meets and on forums what experiences people have had with various systems.
If you live in the UK and your car was registered before August 1992 then you can fit a cat bypass pipe which simply replaces the restrictive catalytic converter with a length of pipe. If it was registered after this then it will not get through the MOT test without a cat although people have been known to run without the cat and just replace it to get the MOT ticket once a year. The engine won't produce a whole lot more power but should rev a bit more eagerly and feel a bit freer at the top of the rev range.
The next stage is to replace the supercharger pulley with one of a smaller diameter. This spins the charger faster which causes it to produce more boost. You also need to rechip the engine so it is mapped to deliver more fuel to go with this extra air. Of course your fuel economy will get a bit worse but it is basically 30bhp (and 30 ft/lb) for a mere £200. Do not buy a chip from an unknown or unreputable source as a poor map could kill your engine. There are a surprising number of crap chips out there so be sure of what you are buying.
Simon runs his car with a Jabbasport chip which has been very good, particularly at retaining the factory drivability and smoothness although it does seem to overfuel which whilst preventing pinking (by stopping the engine leaning out) is unnecessary and rather costly at the pump. An alternative is an SNS chip which comes with copyrighted anti lag mapping. This basically removes the initial delay in throttle response and makes the car more responsive and aggressive. There are a number of different pulley sizes to go for.
The standard pulley is 78mm diameter and most people replace this with a 68mm pulley. This gives a good amount of extra grunt without losing any engine flexibility or affecting reliability that much. The next step down is a 65mm pulley and although this equates to more grunt again, it does not lead to much more than a 68mm pulley as the charger reaches peak flow capacity. What it does do is move the power further down the rev range which reduces the benefit of taking the engine to the red line. A 65mm pulley will, however, reduce charger servicing intervals. Some people have been known to fit a 60mm pulley but rebuilds are required super-regularly.
It is also worth noting that with smaller pulleys (65mm or less and to a small extent with a 68mm) you will experience a degree of belt slip which can be overcome by fitting a toothed belt drive system although these are not cheap at about £400. Please note that having selected your pulley size you need a chip that is mapped to match so you cannot interchange pulleys and retain the same chip. Having fitted a smaller pulley the standard belt will be too slack. This can be overcome in two ways, either by fitting a shorted belt (G-Werks £20) or by chopping the end off the belt tensioner and fitting a shorter end cap (Jabbasport). A complete chip, pulley and belt/cap kit will set you back a very reasonable £200. As mentioned earlier it is worth upgrading to the W5DPO G40 spark plugs at this point. If you go for the smaller 65mm pulley you may wish to consider an uprated fuel regulator as well as red top injectors which flow more fuel than the standard items.
The next stage is to modify the charger by porting its upper chamber and outlet, you can then bolt an RSR outlet (G-Werks £70) onto it which replaces the standard charger baffle box and flows air slightly better as well as looking the mutt's nuts. Charger modding is best done at the rebuild stage although can be done in isolation if the charger has had a recent standard rebuild.
The G60 uses a boost re-circulation system which mainly for emissions and noise reasons feeds un-used boost back into the charger. Unfortunately this un-used boost is roaring hot and so not as useful as good old fresh air in terms of O2 content. This recirculation system can be junked and the secondary charger inlet blocked off with a blanking plate. This will result in the charger drawing only fresh cold air (better for performance and pinking) and running a bit cooler. The re-circulated air can be vented to atmosphere and you get a nice "woosh" on full throttle gear changes when this happens. The crank case and cam case oil breathers feed into the old re-circ pipe so a breather filter and catch tank need to be added following removal of the pipe.
If you own a Golf (without air con) then you can sit back and give your wallet a rest now but for Corrado owners the next stage is £500 worth of BIG intercooler or a chargecooler kit to replace the weedy standard item. Full sized Golf units are popular but they are not cheap (as well as being second hand) so it is worth doing a bit of research with the likes of Pace, Mocal, Blitz etc regarding bespoke items. Jabbasport and Pace and Stealth can all supply chargecooler kits.
Any further performance gains require changes to the engine itself. The first port of call is the cam shaft, however opinion is divided. With any forced induction engine you need to be very careful with camshaft duration; if you have any valve overlap then you end up leaking precious boost out of the exhaust valves or on low throttle the positive exhaust pressure actually stalls the flow of the incoming boost. A lot of people recommend sticking with the standard cam on a G60. If however you simply want more power and can put up with a slightly lumpy idle and a slight loss of low down tractability go for a Schrick 268/276 (split profile) or a Piper 260 degree G60PB270H (symmetric profile). Dan runs a Piper cam in his G60 with a 65mm pulley and apart from a slightly lumpy idle it pulls like a steam train from about 1,200 rpm and overcomes traction in most gears at most speeds. Remember that you will also benefit from a re-map following a new cam.
The next mods are all based on conventional engine tuning so gas-flowed heads and 1.9 or 2.0 litre blocks will all help your G60 whip Impreza-man off the line (and all the way down the road for that matter), and for this sort of thing you can turn to conventional engine specialists rather than G60 specialists. If you still don't have enough power then buy a VR6 and stick a Vortex blower on it, drop a R32 lump into the engine bay or a tuned till it pops 1.8T lump.
Finally… for all you doom and gloom mongers, what to do if your charger decides that it has had enough and disassembles itself into you engine bay.
Well…. There are a number of options, none of which are as expensive as they were a few years ago. VW charge an eye watering £1,500 + VAT for a new charger but Pitstop Developments and G-Werks can sell you a brand spankers VAG charger for about a grand or a warranty'd and reconditioned charger for about £800. If this is still too much you can hunt around for a second hand one but "caveat emptor" (buyer beware) really does apply. People ask a lot of money for chargers that could be in any old state so unless you know exactly what you are looking at and the seller can produce some evidence of servicing/rebuilds you probably want to steer clear. If you pay £400 for a second hand unit that then needs a £400 rebuild you may as well have just brought a risk free reconditioned g-lader in the first place.
You can replace the g-lader with a bomb proof Eaton charger but these are Rootes type blowers and work completely differently to the G-Lader which means they will sound different as well as performing differently. They reach peak flow capacity pretty much straight away and so produce the same amount of boost throughout the rev range. The G-lader however produces more boost the faster it spins giving it unique performance characteristics.
An Eaton blower used to be a good idea when replacement G60s cost close
to £2k but with prices tumbling they look less appealing now. G60s are ultimately also able to flow more air (unless of course you resort to a Mad Max size charger). Rootes type blowers are
however pretty much maintenance free and do not therefore require regular rebuilds. Finally you can ditch the supercharger and fit a turbo instead. This is cheap, simple and reliable and
historically such conversions have produced lots of power. Obviously you suffer the drawbacks of turbo charging (lag and on/off boost) which were eliminated by the supercharger. However if
power is your goal and you are on a budget this is not a bad route to go down.
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