36 replies to this topic

[[email protected]]

Hi,

As ridiculous as this may sound, i wonder if anyone could tell me how you would acheive a compression ratio this high on a 1430 engine? skimming? piston dishes? what else?

any help would be great,

cheers,

Mike

[Saxo-Fiesta-Mini]

ud want domed pistons and about 2mm skimmed off the head gonna be a fun one lol why not ask mini sport if possible theyve spent 40 years with the a series engine id start there

[Paul Wiginton]

Surely you would just skim the head to achieve the cc you need.

Swiftune have proven that anything over 12:1 is a waste of time, theres no power increase just more risk of blowing up. Why do you want to go that high?

Paul

[Guess-Works.com]

Why ????

as above... all you're doing is asking for trouble, and what do you intend on running it with.... Ethanol ?

[998dave]

Why ????

as above... all you're doing is asking for trouble, and what do you intend on running it with.... Ethanol ?

Or Diesel? (injectors in through the spark plug holes - we could be onto something)

[[email protected]]

who said i wanted to do it? i definately didn't say it :>

i'm just curious as one of the fortec minis is running 15:1 in a 1330! and they are quick so wondered how you achieve it?
anyway, why is it a waste going above 12:1?
from what i gather, miglias have far higher compression ratios than that......and its gonna take quite a bit to overtake a mini that does 0-60 in 4.5 seconds when it's only a 1293 bore????????

cheers for the replys,

Mike

[Paul Wiginton]

Swiftune build among the best Miglia engines. They have their own dynomometer and have been building race engines longer than Ive been alive. They found from experience that there is no power gains over 12 - 12.5:1

Paul

[Jammy]

I agree that there is a little need, unless you are really going for something out of left side (diesel, etc). But you'd want a group-A head gasket too.

[jaydee]

i'm just curious as one of the fortec minis is running 15:1 in a 1330!

..Which kinda petrol they're using?? f1 fuel?

[Wil_h]

And Migs don't get to 60 in 4.5 secs. Its BS spread around as marketing.

[[email protected]]

Righty, thanks guys! I know Swiftune build amongst the best miglia engines as Bill Sollis decided to use them as replacement engine builder (so they must be something special)! So is there no logical reason why these people go higher than 12.5:1? they must do it for something?

by the way, what's BS?

so how would you achieve 12.5:1? how much would you skim off the head and how big should the dish be in the pistons? is there anything else to take into consideration?

and out of interest, how do the miglias accelerate so well from low speeds with the STR930 cam? Is it because of the high compression ratio? David Vizards book says that raising the compression ratio adds torque low down in the rev range! So would this be how they achieve their amazing power characteristics through all the low, mid and high rev ranges?

Cheers guys,

Appreciate the help,

Mike

[benb12]

by the way, what's BS?

Brown stuff that comes out the back of a bull.

[Paul Wiginton]

Righty, thanks guys! I know Swiftune build amongst the best miglia engines as Bill Sollis decided to use them as replacement engine builder (so they must be something special)! So is there no logical reason why these people go higher than 12.5:1? they must do it for something?

by the way, what's BS?

so how would you achieve 12.5:1? how much would you skim off the head and how big should the dish be in the pistons? is there anything else to take into consideration?

and out of interest, how do the miglias accelerate so well from low speeds with the STR930 cam? Is it because of the high compression ratio? David Vizards book says that raising the compression ratio adds torque low down in the rev range! So would this be how they achieve their amazing power characteristics through all the low, mid and high rev ranges?

Cheers guys,

Appreciate the help,

Mike

To be honest I dont know why they would do that kind of ratio, they obviously think there is some kind of gain.

My 12;1 compression is achieved with 7cc offset dich pistons and the head machined to suit, cant remember the head cc at the mo.

Migs accellerate so well by keeping the revs up above 5,000rpm all the time. The crank and rods are lightened extensively along with a high diff ratio, this allows the driver to not let it get under 5,000 (ish) when it would 'fall off cam'

Paul

[mini7boy]

Mini Miglia engines are only allowed 11:1 compression.

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

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

[Dan]

Which kinda petrol they're using?? f1 fuel?

Formula One rules say that normal road fuel must be used so presumably not.

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

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

And the fact that the cars weigh about 14 Kg, driver included.