carmad
Posted a lot
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i have a question does a super charger run better on a low compression engine? i have a 2.0 turbo engine so its low compression they usually run 18 psi i bought it with no turbo i have how ever a mini eaton supercharger lying about and i would be handy at making a mount / belt arrangement would it run ok or would it need more/less boost think you see where i am going here ?     |
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a supercharger is basically a turbo but belt driven, so low compression is needed to stop det ( or very high octane fuel and exact mapping) as for the eaton m45 its a bit small for a 2.0, it will make more power, but will be running excessively hot unless you run it through a large intercooler. just make sure you run it at less than 14k, as this is when they start to self destruct if you need any more info just ask  |
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carmad
Posted a lot
Posts: 2,000
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thanks for the reply
i take it that 14k means 14000 rpm at the input shaft off the charger (does maths in head )
this engine will rev to 7500 in the red
so i need a pully that will spin it 2 times for 1 engine revoltution ??
what super charger would you recomend ?
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yeah 14k at the charger.
for a 2.0 i would go for a merc m62 or if you can find one a jag m90 form the 6 cylinder.
but then again it all depends, what boost will you be running ?
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carmad
Posted a lot
Posts: 2,000
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Last Edit: May 2, 2010 19:46:31 GMT by ruishy1
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The thing is when they spin too fast the air get very hot and thats no good.
Better to have a bigger charger and drive it slower
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1985 Bedford CF2 camper 1991 Volvo 240 Turbo |
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The thing is when they spin too fast the air get very hot and thats no good. Better to have a bigger charger and drive it slower thats not strictly true, take the eaton m90 and m112, when you spin them both to produce 9 psi, the m90 produces less heat than the m112. but when you push the boost higher up, the efficiency shifts and the m112 produces less than the m90  |
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carmad
Posted a lot
Posts: 2,000
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take it you can intercool them same as you would a turbo
tho on which side of the charger ?? before or after ??
guessing the charged pipe same as a turbo ??
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yes you can intercool them, the air exits from the bottom, which you pass through the intercooler to the TB.
simply make up a plate that bolts to the bottom with a bit of 2.5" hose welded on and that gives you your air outlet from it.
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carmad
Posted a lot
Posts: 2,000
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last question lol
take it that the standard map thats on the ecu for said engine
will be all wrong now as the boost comes in different
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not entirely, the ecu will adjust to a certain degree. is it map or maf based ?
no worries with the questions mate, glad to help
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carmad
Posted a lot
Posts: 2,000
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whats maf??
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i have just done my dissertation on supercharging a ford 1500 pre crossflow with an eaton m45,
what you need to consider is how the car the engine is going into is going to be driven much in the same way as matching a turbo - small turbo spools up quicker which is great low down for town driving but runs out of puff quicker
a larger turbo works in the opposite way.
as mentioned before a supercharger is a mechanical device that works in a similar way to a turbo but is driven by the a mechanical linkage between the engine and the supercharger
again as mentioned before the max speed of a supercharger is its achillies heel but if you want max boost at x rpm but you want to rev higher some superchargers including the some mercedes eaton superchargers have a magnetic clutch that engages/disengages at a particular engine speed in the same way as an air conditioning pump does - the benefit of this is that you can turn it off when cruising on the motorway or revving too high
if you are clever about it with an aftermarket ecu you can use an output such as a shift light to disengage the clutch at higher speeds and then kick back in when your foot comes down
thats the best i can tell you as my disertation was theoretical and used engine simulation software - unfortunatly the funds are a bit lacking at the moment
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1966 Ford Cortina GT
2018 Ford Fiesta ST
Full time engineer, part time waffler on Youtube - see Jim_Builds
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