89 replies to this topic

[1987_ParkLane]

To work out the size of the pulley you need to first decide what bhp you are aiming for then calculate what airflow you'll need to achieve this. The psi will then be dictated by the airflow and the cc of the engine.

Once you know the airflow needed you can find out at what rpm the M45 will deliver the required flow (by reading of the flow map). It should then be easy to calculate what size pulley will give the required speed

Thanks for that Wil.

I think I am going to work out the required pully needed, then see if I can get one made up, I might know a company that will do it .

[1275 SPRITE]

To work out the size of the pulley you need to first decide what bhp you are aiming for then calculate what airflow you'll need to achieve this. The psi will then be dictated by the airflow and the cc of the engine.

Once you know the airflow needed you can find out at what rpm the M45 will deliver the required flow (by reading of the flow map). It should then be easy to calculate what size pulley will give the required speed

Thanks for that Wil.

I think I am going to work out the required pully needed, then see if I can get one made up, I might know a company that will do it .

Will_H would you be able to help us work out the required pulley size for Dan's (1987_ParkLane) supercharged engine if we give you the information please?
Thanks,

James.

[1987_ParkLane]

Will_H would you be able to help us work out the required pulley size for Dan's (1987_ParkLane) supercharged engine if we give you the information please?
Thanks,

James.

I have PM'd him lol, but not to generally work out my size lol, but if you could that would be great , or just a little more info on how to .

[998city]

as i am using a standard bottom pulley and normal standard pulley on the charger could i just make the compression lower to stop problems etc

[1987_ParkLane]

as i am using a standard bottom pulley and normal standard pulley on the charger could i just make the compression lower to stop problems etc

You should really do all the head work, etc to lower the compression.

[998city]

i would rather not as i am just doing this as a project and i would like to put it onto another car and convert mine back and i just really want to see if its any good. and plus it is cheaper

[1987_ParkLane]

i would rather not as i am just doing this as a project and i would like to put it onto another car and convert mine back and i just really want to see if its any good. and plus it is cheaper

Well then the only real way to lower the compression more is to use a decompression plate.

[998city]

well would a 6cc decomplate work well enough to run a standard bottom pulley and a standard supercharger?

[1987_ParkLane]

well would a 6cc decomplate work well enough to run a standard bottom pulley and a standard supercharger?

It would be best to work out the correct one for the application, I have seen 3cc, 6cc and 9cc decompression plates for the mini .

[blister]

do you know how to work it out?

[1275 SPRITE]

Here is the way I was taught but might be a little wrong?

For a 998

998/4 = 249.5cc per cylinder

249.5 + head chamber cc (24cc???)

= 273.5 + decomp plate (6cc)

= 279.5cc

+ 4cc (head gaskets)

= 283.5

283.5 / 34cc (head cc + decomp plate + gaskets)

= 8.33 : 1

That is only guessing at 24cc in the head and for a 6cc decomp plate and 4cc for head gaskets.

This is not taking in ring land volume which is something like 0.5cc

This is assuming its 998 too

Hope this helps?

James

[998city]

so a 6cc will be perfect to run with then?

i will be using a 6cc decom plate with two head gaskets with the jonspeed bottom pulley and a eaton m45 supercharger

do i need longer choke and throttle?
also what about if i wrapped the intake in a nitrous bottle heater? or similar to help with carb icing?

[1987_ParkLane]

so a 6cc will be perfect to run with then?

i will be using a 6cc decom plate with two head gaskets with the jonspeed bottom pulley and a eaton m45 supercharger

do i need longer choke and throttle?
also what about if i wrapped the intake in a nitrous bottle heater? or similar to help with carb icing?

Depends where you have your carb. If you have the the long 'carb to charger' pipe then yes, you can get them Vmax Scart for £7 each. Also do you have a servo?

[998city]

no servo yeah and i have the long vmax scart one that puts it near the coil?
does vmax have a online shop or do i need to buy it over the phone?

if i am buying the longer choke/throttle is it worth buying the other things he has for sale like?

steady bracket £10
supercharger gaskets (2) inlet and charger case £15
reinforced manifold gasket £12
longer throttle and choke cables £7 / £7
carb needle and seat (fitted to item obove ) £30
thermostat low temp £4

new timing cover with seal - no breather £30 <<< i am thinking that i dont need this as its going on a 998 i am right arnt i?

also he has a lcb for sale you dont need a different one if your fitting the charger to a mini that already has stage one fitted right?

[1987_ParkLane]

no servo yeah and i have the long vmax scart one that puts it near the coil?
does vmax have a online shop or do i need to buy it over the phone?

if i am buying the longer choke/throttle is it worth buying the other things he has for sale like?

steady bracket £10
supercharger gaskets (2) inlet and charger case £15
reinforced manifold gasket £12
longer throttle and choke cables £7 / £7
carb needle and seat (fitted to item obove ) £30
thermostat low temp £4

new timing cover with seal - no breather £30 <<< i am thinking that i dont need this as its going on a 998 i am right arnt i?

also he has a lcb for sale you dont need a different one if your fitting the charger to a mini that already has stage one fitted right?

If your running no servo, you need to get the servo blank for £3.

Also Wil linked me to a picture of the Eaton 45 air flow graph thing: LINK