super charger

Lets take the MA12 as a hypothetical. If we wanted to run 7psi/0.5bar, you would need a 6:1 pulley ratio to use a 300cc charger. If that charger has a max operating RPM of 24,000rpm you could only run it up to 4k RPM. So you wpuld want to size your turbo so that it hit 0.5 bar of boost at just before 4k rpm so when you disconnect the s/c you don't drop any boost.
In this way, you get massive boost from idle, the tiny s/c doesn't sap too much power from the engine, and the turbo can take over at higher revs where it is most efficient :)
 
I see that , but if used in conjunction with turbo , and geared right, disconnected at 3-4k rpm , should be fine.....I think. ;)

I guess the hard part is the actual electro clutch part, and finding one that'll fit that doesn't cost hundreds
 
Just for you Pork ;)

For CG13 with M45 at 1bar:
4:1 pulley system needed (roughly) to get 1bar, max rpm of M45 is 14k rpm so max engine speed with s/c engaged is 3.5k
At 1bar boost, a 1.3 acts very roughly like a 2.6l engine, so find a turbo that will generate 1bar boost on a 2.6l engine from 3.5k revs and tack that on the end.
Edit: T3, T4 or GT35R look like possibilities.
 
pork said:
I see that , but if used in conjunction with turbo , and geared right, disconnected at 3-4k rpm , should be fine.....I think. ;)

I guess the hard part is the actual electro clutch part, and finding one that'll fit that doesn't cost hundreds
Click to expand...
Could run a seperate belt for the charger and have an idler pully on a solenoid that drops tension from the belt when energised if you don't mind keeping spare belts in the boot
 
Enuo said:
Could run a seperate belt for the charger and have an idler pully on a solenoid that drops tension from the belt when energised if you don't mind keeping spare belts in the boot
Click to expand...
Haha , nice idea , bit pricey on the belts tho!

Wouldn't it be better to use smallest charger as possible, somthing that's ginna be at it's full boost at 3-4k then swap to turbo

If an m45 is only being used at 50% capacity before turbo , then you might as well jus supercharge and nothing ejsr
 
Dunno yet , havnt tried it that high , actuator opens at 0.5, but as soon as it's at 3.5 k, it goes straight onto ot
 
pork said:
I see that , but if used in conjunction with turbo , and geared right, disconnected at 3-4k rpm , should be fine.....I think. ;)

I guess the hard part is the actual electro clutch part, and finding one that'll fit that doesn't cost hundreds
Click to expand...
Didn't realise you were on about twin charging, sorry, I missed like half the thread before posting that haha.


'Sent from my bed using paper planes'
 
You lot are all too fussy
For Neil's setup it would be fine. And if mounted pre turbo like the TSi idea you wouldn't need air to flow through. Keeping the simple electro clutch and the bypass valve.
I only skipped through to catch up but if it were me I'd be buying that supercharger now ;)
It maxes out as the turbo will take over. Neil is only running 7 psi iirc so the s/c only has to make 3.5psi ans if its capable of more then use it :)
 
h701micra said:
You lot are all too fussy
For Neil's setup it would be fine. And if mounted pre turbo like the TSi idea you wouldn't need air to flow through. Keeping the simple electro clutch and the bypass valve.
I only skipped through to catch up but if it were me I'd be buying that supercharger now ;)
It maxes out as the turbo will take over. Neil is only running 7 psi iirc so the s/c only has to make 3.5psi ans if its capable of more then use it :)
Click to expand...
if you overspeed the charger the bearings will melt
 
If you run a fixed displacement pump before a continuous flow pump, the continuous flow pump will not multiply the pressure.
 
the CG inlet valves close when the piston has risen 19mm from BDC iirc, so at low rpm the VE is gonna be 75% at best i guess.
but from about 4 k onwards those late closing inlet valves come into effect, so S/C calculations will be different for a super-turbo than a S/C only setup i guess
 
frank said:
the CG inlet valves close when the piston has risen 19mm from BDC iirc, so at low rpm the VE is gonna be 75% at best i guess.
but from about 4 k onwards those late closing inlet valves come into effect, so S/C calculations will be different for a super-turbo than a S/C only setup i guess
Click to expand...
Doesn't matter I don't reckon, the air from the supercharger can't back up and slow the compressor like on a turbo, it HAS to escape through the engine, so whatever volume of uncompressed air it moves per engine revolution it ends up in the cylinders. The pressure will spike slightly just before the intake valve closes though, if the valve closes after bdc...
 
Going by an online engine flow calculator with VE at 80% a 1.3 will flow at. 64 cfm at 3.5 k

So going by that , how would you work out the right s\c required
 
pork said:
Going by an online engine flow calculator with VE at 80% a 1.3 will flow at. 64 cfm at 3.5 k

So going by that , how would you work out the right s\c required
Click to expand...
thats at atmospheric pressure eh neil, and as the boost rises the VE will rise accordingly
 
pork said:
Pressure I want , or pressure that the example used?

The example was a n/ a 1.3

Let's go with 0.5 bar pressure and work from there
Click to expand...
Ok, so assuming you want use the VE (80%)
0.5 bar boost = 1.5bar actual
1300cc capacity x 80% = 1040cc (1000cc)
1.5x1000cc = 1500cc required air at atmospheric
To test suitability of a s/c, find its displacement/revolution and divide required air by this to get drive ratio
Find maximum spin speed of s/c and devide by drive ratio to find maximum engine revs the sc can be used at.
 
Enuo said:
Ok, so assuming you want use the VE (80%)
0.5 bar boost = 1.5bar actual
1300cc capacity x 80% = 1040cc (1000cc)
1.5x1000cc = 1500cc required air at atmospheric
To test suitability of a s/c, find its displacement/revolution and divide required air by this to get drive ratio
Find maximum spin speed of s/c and devide by drive ratio to find maximum engine revs the sc can be used at.
Click to expand...


Cool !!

So using this map of an m24

aperepuj.jpg


Can wa determine if it's suitable
 
h701micra said:
Care to explain that graph to me :/
Click to expand...
It's like thermal efficiency at pressure, rpm etc and temperature rise. That sort of thing. Can use it to work out how big an intercooler you need, when power will start dropping off in rev range etc with it iirc
 
Enuo said:
It's like thermal efficiency at pressure, rpm etc and temperature rise. That sort of thing. Can use it to work out how big an intercooler you need, when power will start dropping off in rev range etc with it iirc
Click to expand...
Sounds useful. I wouldn't know how to interpret data from it though. The fact I can't read the units of measure because they're in german doesn't help :p
 
Enuo said:
So technically its pressure ratio
Click to expand...
I assume that this will be related to the cfm of the head?
Or
Is it related to the construction of the 2 manifolds, turbo and plenum etc etc? In which case we can directly affect this by modifying a plenum for example
 

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