Push the gear stick to the left, SPORT mode.

Pulley is around £300 from what I have read and I will get the remap from the guy who used to supply me with files when i was remapping cars.

Prob wont get round to remapping it. Unless it is done live there is very little to be gained anyway from the remap. From what I have read it runs rich so maybe there is some power to be gained optimising the fuel.

The ecu is more than capable of coping with an extra 2 or 3 psi. not sure where the boost limit is but i guess it will be higher than + 3 psi.

1psi extra makes around 10bhp on a 2000cc car. So + 3psi on a 4200cc car should easy give 30 to40 extra bhp IF i can keep the intake temps down.

My plan will be.

2.5 to 3psi pulley.

Charge cooler mods including higher flow pump. Maybe bigger charge cooler rad but not sure if this will gain any cooling.

De-cat pipe. Maybe look at freer flowing exhaust as well.

Look at cold air feed for air cleaner and increased flow.

That should release around +40 to 50bhp??

Yes pulley is DIY job but you will need some sort of puller to get it off and i believe the 2.5psi pulley requires the nose of the superchraged to be modded slightly. Again DIY job if you are careful.

I will do some runs before and after as i mod my car just to see if the mods actually work Cayenne Turbo "S" 521bhp Standard

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paulmc wrote:

which pulley. 1.5 or 2.5psi increase? I am going to go with 2.5 psi increase and fit a larger flow intercooler pump and maybe look at flowing the inlet manifold and supercharger. Inlet temps seem really high. need to get these down to make good power.

Did it make a did difference?? Cayenne Turbo "S" 521bhp Standard

www.bmw535d.co.uk

Does any of this stuff cause reliability concerns?

I doubt i could fit this DIY anyway so i will have to factor in labour costs

Not sure, I am a turbo man usually, +2.5psi extra is nothing for a turbo but not sure on a supercharger. I doubt it will cause any issues though.

I will do a "how to" on changing the pulley but it will be a couple of months away by the time I find a car and get round to fitting the smaller pulley Cayenne Turbo "S" 521bhp Standard

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Don’t expect a linear power improvement with increasing the psi, the eaton is already it its maximum efficiency, and increasing the speed will take more power form your engine and also increase heat which works contra productive to the power delivered to the wheels. Lower end you will get more power, and the car picks up earlier (*as the supercharger is turning quicker), but top end you will not gain that much if at all. But low-end/mid range is of course already good.

If it is only an occasional power use (so a couple of seconds and then a long time no power usage) than you will not really notice the heat buildup in the system, which will rob you power. If you want to use it more than it is better to also work on the intercooler cooling, as that will ensure you lose less power once the system heats up (and that goes quick).

Here is a cheaper example of just an upper pulley (same effect), and you can also have a machine shop make one for you for half that price:
http://cgi.ebay.co.uk/Jaguar-XKR-XJR-S-Typ...1e5fe5c1f0
(ps I don't believe the performance increase as mentioned, he has never shown a dyno, nor have ever seen any creditable dynos from others either...)

I have had a 4.2 RRS already above 500 hp (with a twin-screw though) and the engine has shown its strength (also in my XKR which has the same engine), and the gearbox is pretty strong too. RRS SDV6 HEV Dynamic
XKR 700 BHP with Twin-screw and LSD

Going from my old cossie days 3 psi will easy make 50 or 60bhp extra on a 4200cc engine but it is prob going to take and extra 20bhp to turn the charger faster higher up the rev range. As you rightly say the compressor is more or less flat out in terms of efficience and turning it faster has a huge effect on charge temperature.

Give me a turbo anyday. Cayenne Turbo "S" 521bhp Standard

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Turbos do require less engine power than the superchargers, so there (if your engine (/cams) are designed for it) a turbo will easier add power. But there are some better superchargers then the eatons roots one like the twin-screws that require less power from the engine up to very high boost levels. The benifit in general of superchargers is that they provide already good boost at low rpm ranges.

Here was a calculation I made once (based on the graphs frm eaton themselves) to illustrate the power requirements/extra heat you get with the eaton:

Click image to enlarge

Click image to enlarge

I also have that graphs from the m112, handy to have.

Your calcs looks pretty good. Only + 16bhp at the top end is a rubbish gain but i bet you aint are off

i intend porting my charger as well as intercooler mods so maybe get a bit more flow and slightly lower temps. i will de-cat it as well. I used to run a Audi s4 v6 twin turbo and when i deleted the cats i could run 2 degrees more ignition advance with no det. remvoing cats deffo increase flow especially on charged engines. Cayenne Turbo "S" 521bhp Standard

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These are not exact figures, but it does illustrate what happens. Lower end the gains are more. I also think a package like je engineering has (so pulley, exhaust, high flow cats and a custom tune) could maybe add 40 or 50 bhp as they claim, just gets pricy. RRS SDV6 HEV Dynamic
XKR 700 BHP with Twin-screw and LSD

i wont be using high flow cats. i will remove the cats and get de-cat pipes made and put the cats back on for the MOT. Depending on how good or bad the standard exhaust looks i will either get a new one made or just fit better back boxes. I have a 4 post ramp at my house so easy enough job. I can also get a remap pretty cheap from my tuner guy. Cayenne Turbo "S" 521bhp Standard

www.bmw535d.co.uk

avos wrote:

Turbos do require less engine power than the superchargers, so there (if your engine (/cams) are designed for it) a turbo will easier add power. But there are some better superchargers then the eatons roots one like the twin-screws that require less power from the engine up to very high boost levels. The benifit in general of superchargers is that they provide already good boost at low rpm ranges.

Here was a calculation I made once (based on the graphs frm eaton themselves) to illustrate the power requirements/extra heat you get with the eaton:

Click image to enlarge

Click image to enlarge

This is just an estimate of course, but it should give some idea.

Yes he does but kit is Round £4500gbp. The supercharger is not that expensive but all the fabricated bits to make it fit cost the money Cayenne Turbo "S" 521bhp Standard

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It's more £4800 if you want the bigger better Supercharger! But from what I understand it will leave the new 5.0Ltr S/C RRs for dead - I'm saving up!!  Cheers Laurence.