Eaton ABF - calculating pulley size

bigbeat where abouts are you in essex? as am also in essex leigh on sea

 

You have also think in terms of what airflow does a std ABF engine in good tune achieve,
If that was Matts old lump, then in my money I would say approx, 160bhp@ 6000rpm and 155lbft at 4900rpm, based on the GerTIe the original car from how to ABF your Mk2.
You can use this torque plot to track what the engine VE is doing and work out airflow for the NASP set up.
Max VE on a NASP engine like this will get to ~93%.
With the charger added, gear the unit for rpm that would deliver much more air mass through the system according the the compressor map as seen a few post earlier. Start with engine speeds between 2000rpm to 6000rpm. Look at the charger graph and study the relationship between NASP engine airflow @WOT for given speed and what airlflow the charger can deliver at its current gearing. For example an ABF engine at 5000rpm is inhaling 300m^3/hr of air at WOT. Asuming the gearing is @ 1.85 times the crank damper, the charger at 9250rpm is flowing ~375m^3/hr meaning a PR of 1.25 or 0.25bar or 4PSi of boost pressure all things being equal, which it will not be.
If this were a M62 unit then at this speed you will be flowing more than 550m^3/hr.
Back to the W203 M45 unit spining at this speed, add an intercooler with efficiency of less than 75% and you have manifold boost of less than 3psi, correct for manifold density even less, belt slip...you get the picture...

 

very nice sum up ^^^

 

You have a message on its way to you.

That is a nice quick guide there Toyo, I'm going to have to get the calculator out again.

 

That is not problem matey.

Remember you already got a running car. It just needs a bit of very small guidance and you are there.
Let me know how you get on.
You maybe suprised. I am actually closer to your location than you think .

Bigbeat, time for you to get cracking with that thing!!!!.

 

It's almost there! The engine is more or less finished. I just need to put it in the car and finish the wiring, but the driveway is being dug up so I haven't got access to it.

 

we will all have to get our supercharged heads together at some point if we are all that close lol!

 

Like Toyo said 'WHY'?
m45 can be made to work well. When using the m45 With loads of wheel spin and a poor 60 feet time of 2.6I still got a 14.3 @ 99.8mph.

Stick with it dude.

 

Looks like you'll need a ratio over 2 to get anywhere near the 10psi/0.7bar these are meant to be good for

Edit : A pulley ratio i mean.

 

You may even be able to push it to 12 keeping in the 55% efficiency island if that compressor map matches your charger.

 

Slightly off topic, can someone just breakdown this map for me. I understand the bottom axis, but the rest I'm unsure;
the dotted line numbers (1000s) the rpm?
y axis?
are the figures along the map lines (50, 55, etc) the efficency?

 

The Y axis = Pressure ratio i.e. gauge plus ambient
X axis = Supercharger speed.
Z axis = Supercharger efficiency. You want to be in in the highest land.