89 replies to this topic

[Prawn]

I don't understand why anyone would want to build a suck through kit..... it's such a compromise.

[998city]

cheap and better then not having one
getting a supercharger and a intercooler in there for best benefit in a mini engine bay would be insane

[Wil_h]

If you run a 998 with an M45 on 1:1 pulleys then you wil produce way too much. Lots of heat, and most likely melted pistons. seriously consider calculating a suitable drive ratio.

[998city]

how would i go about calculating the best ratio?
i have been told my vmax that it will be fine to run the same bottom pulley as a 1275 would but i have to keep the one fitted to the bmw charger the same and i cannot decrease its size

[blister]

done some more research today and found out that

1. as i am going to put it on a 998 i dont need to mod the timing cover
2. as i am not going over 100bhp i dont need to upgrade clutch and fuel pump
3. the exhaust manifold needs to be modified??? <<<< is this true
4. and the supercharger does not just bolt onto its manifold <<<< is this also true?

oh and i would also like to know what decompression plate cc is the best to use for my 998 i dont want to cut away at the head or put in dished pistons because i might not like the supercharger and would like to resort back to normal

[blister]

sorry for kind of hijacking the thread

[1987_ParkLane]

Here are the pictures of my bottom pully:







It is brand new, never been used, it is the one JonSpeed make (hence their name on it), it is made from aliminum, so nice and lightweight.

Also I am getting rid of my decompression plate:



So if anyine wants either, give me a PM .

[1275 SPRITE]

It the decomp plate new? And a 998 one?

[Wil_h]

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

[1987_ParkLane]

It the decomp plate new? And a 998 one?

The decompression plate is new, and I'm sure it is for a 998, as that was the kit I asked for when I bought it.

[998city]

i would like about 100bhp or just under

[998city]

how do i calculator how much airflow i need?

[998city]

also i got a tims boost gauge can i connect it up to use with the m45?

[998city]

.

Edited by 998city, 18 June 2009 - 08:24 PM.

[blister]

if possible could someone help me out on this>?