92 replies to this topic

[[email protected]]

Hi guys,

I have heard people say that superchargers can perform in line with turbocharged engines......hence up to 200 bhp! (and even 225bhp with Matt's turbo).

If this is the case, why haven't i seen a supercharged mini with these sort of power figures yet? Do they exist? I don't think i've even seen anyone running high boost superchargers...everyone that i have seen seems to stick with relatively standard pulleys!


If someone has one (200bhp supercharger....or even 160 ish?), then please point me in the right direction?

Me and a friend aim to build a supercharged engine with at least 160bhp!

Please could you advise us of the best setups: which cam profiles to use (and why not to use high end cams such as a 286/296?) , engine capacity, cylinder head work (valve sizes?), and all the other contributing factors....


Any help with this would be great,

Cheers,

Mike

[mini13]

the problem is superchargers (at least the BMW one comonly used on the mini) are not efficient at high boost levels, in fact 10psi is pushing it.

when air is compressed it gets hot, the efficency of the "air pump" affects how hot the air gets for a given pressure rise.

a good modern turbo is generally around 70-75% efficient, where as the Bini charger is around 65%, and drops rapidly above 10psi as mentioned.

add to this that generally charged engines do not run an intercooler where as most turbo lumps do.

essentially, with the low efficency and no intercooler to cool the air back down the engine see's hot "thin" air which will at best drop power, and at worst cause detonation.

However If yoy can find a decent charger of a different desgn (lysholm £££) and rig it up with an intercooler you may be in with a chance of seeing 200hp.

[Wil_h]

I think that^^^^ says it all really. But even blow through with something like a Rotrex that has a relatively efficient compressor, you'll still waste more power driving it than a turbo.

[[email protected]]

So what sort of power is capable with a Eaton charger with intercooler etc??? As Opcon chargers aren't exactly common!

[steble]

as said above you'd have to make it a blow through set up first

my friend has a 160bhp supercharged engine well until he blew it up

i will have a bloody good go at getting mine above 160 but i may go turbo still not decided

[[email protected]]

And how do you make it blow-through with their kits?

[In-a-mini]

you cant with there kits you have to make it yourself and use a turbo carb setup

[johnnysti]

I managed to get 155bhp from my vmax suck through kit on a weber. It was hard work and a real pain to to keep setup and running well. At the moment im running a blow through made for me by slark racing that on standard pulleys is doing about 130bhp. We are fitting a 17% reduced pulley which we are hoping will make a real differance. The best part of the blow through setup so far is its so much more drivable compared to a suck through. Im hoping to get upto 170ish bhp but even if i matched what i had on the old setup i will be more than happy as there is plenty of low down torque now

[Guess-Works.com]

The Stig is currently putting a Blow through setup together...

[Wil_h]

Matematically much over 130 is difficult with a suckthrough M45 setup. With blow through maybe 150 is achievable.

The above figure of 155 suckthrough is slightly optermitic IMO, but I'm just working from a spread sheet. It has been quite accurate for all my turbo engine builds though.

Has anyone got any 1/4 mile times for a SC setup running 10+ psi?

[Prawn]

I don't think any of them have actually made it to the strip without blowing up Will

I was all up for building a blow through M45 setup, I had all the parts and was ready to start building it, then I just woke up one day and realised that even blow through, supercharging was still compromised, and once setup you're very limited in terms of further tuning potential, so I've now decided to go turbo instead, which is a far more exciting prospect!

[johnnysti]

I agree nic. Turbo is far easier to obtain bigger grunt. But for me, turbos been done to death! lol Superchared is more exotic! Also, 155bhp isnt optermistic imo. It done 149.6 bhp at vmax and 154.2 bhp at slarks. But it ran like such a dog i dobti ever got to exploit it!

[johnnysti]

I agree nic. Turbo is far easier to obtain bigger grunt. But for me, turbos been done to death! lol Superchared is more exotic! Also, 155bhp isnt optermistic imo. It done 149.6 bhp at vmax and 154.2 bhp at slarks. But it ran like such a dog i dobti ever got to exploit it!

[Prawn]

I agree nic. Turbo is far easier to obtain bigger grunt. But for me, turbos been done to death! lol Superchared is more exotic!

I know what you mean, I was so up for the supercharged idea, but when I thought about it, I realised, if I wanted more when it was done, there wernt really any options to take it further, due to the inefficiency of the eaton charger. I like the idea of a turbo setup with an EBC, being able to switch between useable everyday sensible power, then just turning a dial to release mental power if and when you need it....

[mini.cooper998]

what about a turbo and supercharger mix tempted wouldnt take a lot of extra work. im going very similar to johnny with a blow through turbo setup could always run that back into the turbo.

what power do we recon

no lag and similar to a few jap motors

would you run the outlet from the supercharger into the inlet of the turbo or vica versa