Supercharger Engine Spec
Turbo Mini Forums

Hi,

I have just started to dismantle an old A+ 1275 block that I have ready to rebuild for my Supercharger which I have bought from Vmax.

At the moment I have this all set up on a 1330cc pretty standard engine and I am looking to get more BHP from it! And have always wanted to rebuild a mini engine (this will be my first one)

The supercharger is an Eaton 45 and I am running a Weber DCOE 45 as well with electronic fuel pump.

I have an Aldon distributor (points).

I have started to try and make a list for the ultimate engine specification but I am not sure what sort of compression ratios I need and what are the best parts to get.

Basically I am looking for some advice on the perfect engine for a supercharger. I am not looking for huge top speeds, I am looking for quickest accelleration.

Here is a list so far:

- Rebore to 1293cc (is this the best for a supercharged engine?)
- Omega deep dish (18cc) forged pistons
I know that these will lower the compression because there is more volume but I have also been advised to stay away from 1380cc engine.. but I would have thought this would lower the compression even further by getting deep dished 73.5mm pistons, is there something I am missing?
- I was advised to a kent 286 cam.
- Vernier duplex timing
- 1.5 Rockers
- Lightened flywheel assembly etc.
- The head, I am not sure yet.
- Straight cut gearbox (i am not sure what sort I should go for here regarding gear ratios etc)

These are the main bits to the engine I suppose, is there anything else I am missing that I may think is insignificant but would actually play a major role!?

Sorry for the massive message, any help on any of these questions would be greatly appreciated.

I have attached a picture of my mini too, this was before the supercharger was fitted (it now doesnt fit under the bonnet properly!)

Thanks,

Ian

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Edited by urbantricker on 11th Oct, 2007.

www.urbantricking.com

You need to work out from your pulley ratios what boost you are likley to be running and then select the bits to give you the compression ratio to suit.

Use this calculator to work out your boost:

You may have to adjust the boost required to work backwards to the ratio you have.

You could go to 1380. A number of guys on here are running high boost on 1380s without a problem. But if you want to be able to rebore the block in the future, aim a bit lower.

Edited by Paul S on 11th Oct, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Here's a link to my album
http://www.turbominis.co.uk/index.php?p=14&album=550

1330 forged omegas, 1.5 rollers, 29cc chambers in the cylinder head, steel centre strap on the crank and nos.

2:1 reduction pulleys spinning the charger to 14000 rpm, upper end of its range and even then just below 10psi so this will be the limiting factor on what is achievable power wise.

Changed the sailsbury lsd/3.44 to a quaife ATB/2.7 recently and apart from not being able to drive slowly in 1st the ratios work well on the road with the torque delivery of the supercharger

Loving the mini btw mate

Back once again like a renegade master

Axel, cheers for the link, seems to work really well I am having a couple of problems with it though. I am not sure what my engine would rev to do you know roughly what an engine of that spec would go to? What is the boost measured in? And also, is the compression ratio the drive ratio?

I have put in engine size of 1.293, max rpm 8000 and boost up to 89 on an eaton 45 supercharger which gets the supercharger rpm just below max is that what I am aaiming for?

Sorry I am quite new to all this.


Nice looking mini, mini23. I couldnt quite read the BHP on the print out you had, what was it?

www.urbantricking.com

Edited by Paul S on 12th Oct, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

My brother has that so I will start reading it as soon as I can!

www.urbantricking.com