17 replies to this topic

[siztenboots]

what sized crank and SC pulley are people running , or pulley ratio if you have that

[Winstar]

clicky

[MartinS]

Why do you need to know that Steve???? You seen the light! Martin s

[Zoobeef]

Twin charge?

[siztenboots]

So diameters are , crank 165mm

added rpm / SC rpm multiplier

64mm / 2.5" ~ 27.5 psi / 2.58
70mm / 2.75" ~ 25 psi / 2.36
75mm / 2.95" ~ 22.5 psi / 2.2
80mm / 3.15" ~ 20 psi / 2.06
85mm / 3.35" ~ 17.5 psi / 1.94
89mm / 3.5" ~15psi / 1.85

so realisticly with a MAX SC rpm of 14,000 , with a 80mm pulley , you are rev restricted on the engine. (2.06 ratio)

trial fit

[N17VES]

clicky

Interesting....


My exige S with the MP62 charger and 2.9" pulley hits 10psi. I've been advised that 10psi is that maximum the MP62 can deliver before the efficiency drops somewhat.

What pulley size are the SC boys using?

[techieboy]

Can never remember what the standard pulley size is on the M62 conversion but Courtenay's are fitting a 2.9" pulley to mine in a couple of weeks. That's right at the edge of the compressors efficiency though. Some of the American's machine the snout of the compressors body to get even smaller pulleys on but God only knows where that lands them on the efficiency charts.

[siztenboots]

clicky

Interesting....


My exige S with the MP62 charger and 2.9" pulley hits 10psi. I've been advised that 10psi is that maximum the MP62 can deliver before the efficiency drops somewhat.

What pulley size are the SC boys using?

I don't what that 10psi is measuring , but is that engine backpressure, exhaust+head+cams+intake

from SC rpm you can see flow, drag, temp rise

[N17VES]

I think the 10psi is measured just before the intercooler - I'm interested to find out excatly how it measured. I've been thinking about swapping to a Harrop on the exige, but nobody in the UK seems to have tried it. Maybe the first once the internals and gearbox are sorted

Edited by N17VES, 19 July 2010 - 03:46 PM.

[Mike (Cliffie)]

Mine is standard, dunno what I am running PSI wise. Would be nice to know... Anybody?

[_Dan_]

Mine is standard, dunno what I am running PSI wise.

Would be nice to know...

Anybody?

I added a vac line up the sill into the cabin so I could tee into the FPR line and measure this.........

...never bothered connecting it up though

[Winstar]

I don't what that 10psi is measuring , but is that engine backpressure, exhaust+head+cams+intake

from SC rpm you can see flow, drag, temp rise

The graphs will be measuring 10psi gauge pressure from the supercharger. Interms of what PSI is on the engine then yes it's really the backpressure or restriction caused by the inlet manifold, valves, etc.

[The Batman]

standard m62 is 3.35 i think im running a 2.9 was going to put a 2.7 on it, but maxed out the supercharger

Edited by joe_589, 19 July 2010 - 04:49 PM.

[siztenboots]

standard m62 is 3.35 i think im running a 2.9 was going to put a 2.7 on it, but maxed out the supercharger

if you are running a 2.95" pulley with standard crank pulley then with a 14,000 rpm maximum limit on the SC , you are limited to crank rpm of 6363 (14,000 / 2.2 )

to go for a 2.75" pulley will restrict your crank rpms even more = 5932 ( 14000 / 2.36 )

sometimes you are better off running bigger pulley and keep temperatures lower and SC drag less as it is not a straight linear curve for each

[Steve B]

With good engine management and water injection the 1.8 MX5 boys with water injection push 300bhp out of the mp62 charger.

[Phear]

Mine is standard, dunno what I am running PSI wise.

Would be nice to know...

Anybody?

I have a (not terribly acurate) boost guage on mine, which measures 0.6 bar at full chat which is about 9 PSI.

[NickB787]

So diameters are , crank 165mm

added rpm / SC rpm multiplier

64mm / 2.5" ~ 27.5 psi / 2.58
70mm / 2.75" ~ 25 psi / 2.36
75mm / 2.95" ~ 22.5 psi / 2.2
80mm / 3.15" ~ 20 psi / 2.06
85mm / 3.35" ~ 17.5 psi / 1.94
89mm / 3.5" ~15psi / 1.85

so realisticly with a MAX SC rpm of 14,000 , with a 80mm pulley , you are rev restricted on the engine. (2.06 ratio)

trial fit

Don't forget those figures are for the Harrop 1.3 lt not the M62 1lt

[siztenboots]

So diameters are , crank 165mm

added rpm / SC rpm multiplier

64mm / 2.5" ~ 27.5 psi / 2.58
70mm / 2.75" ~ 25 psi / 2.36
75mm / 2.95" ~ 22.5 psi / 2.2
80mm / 3.15" ~ 20 psi / 2.06
85mm / 3.35" ~ 17.5 psi / 1.94
89mm / 3.5" ~15psi / 1.85

so realisticly with a MAX SC rpm of 14,000 , with a 80mm pulley , you are rev restricted on the engine. (2.06 ratio)

trial fit

Don't forget those figures are for the Harrop 1.3 lt not the M62 1lt

okay, ignore the pressure figures , but the pulley , ratios and rpm limits is correct

Nick, is yours the HTV1320?

What is the harrup safe max blower rpm, something like 20,000 I have heard?

Edited by siztenboots, 20 July 2010 - 09:22 AM.