36 replies to this topic

[Ethel]

Would have thought supercharging was the wrong choice for the R1 engine, superchargers have low efficiency at high rev's.

Presumably that would entirely depend on the gearing?

[Wil_h]

And the type of supercharger. Rotrex for example are centrifugal compressors, I've seen these on bike engined cars before.

[Nightrain]

Would it not need to be underdriven, as the R1's make max power around 13000rpms ?

[Wil_h]

Depends on how much air you need at that sort of rpm, dependant on power aspirations. The Eaton is specced upto 15500 according to the maps available.

But at around 13,000 rpm it'll pump a little over 500 m^/hr. This is enough for around 200bhp in a 1300cc engine at less than 10psi. Remember the engine is doing 13,000 rpm which is why the boost needed seem low.

[YIANO]

Exactly right !
Lower pressure is needed at these rpms
I've seen r1engines turbod but I prefer the linear delivery of a supercharger and lower heat generation is advantageous

[Wil_h]

I wouldn't say the temps are lower, certinally not with an M45 anyway. At 13,000 rpm it's only around 55% efficient, which means a charge temp around 160 F above ambient! Schorchio!

[Sam Walters]

It ain't that difficult to figure out how they turn good 0-60 times.

It's the TIRES, boys. Get over it.

My mini is lighter, has more power and wider stickier (slick) tYres than a mig. It also has better gear ratios for a fast 0-60 at the expense of top speed. All of this, and my car dosen't get to 60 in 4.5 secs (it's under 5 though according to my timing slip).

This is not to say Migs are rubbish, they are some of the best eveloped minis around, but they don't get to 60 in 4.5 secs.

Try to follow a Miglia through a difficult 100 MPH turn sometime and you'll find out just how rubbish your power is. It can't drive for you.

Wind your neck back in bud.