Fella's,

Whats the go here. My braiin hurts trying to think it through.
If I run higher boost and lower compression OR lower boost and higher compression whats the difference?

Eg/ 8:1 and 12psi instead of 9:1 (or more) and 4-6psi...

Why is one better than the other, etc?

Cheers,
Peter.

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Click here for the Turbo Conversion Thread!

less compression more boost more power higher compression will aid power but wil limit boost.

so set the compression dependent on the boost you want to run.

there is more power increase with boost than compression

but low compression will make it less powerful off boost.

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1152cc turbo A-series now with 125.7hp at the wheels !

AUSSIE Turbo mini forum >> http://boostmini.justboard.net/

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Ok cool. As I thought... so we want to run it like we talked about... big boost

Pete.

PS: Picked up the High Flowed T02 tonight

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Click here for the Turbo Conversion Thread!

Only downside of low compression with a turbo is it'll be a bit s-l-o-w (or a slug) down low before it spools up. Particularly with only 998cc. That's why kazjim rebuilt his last time with a 1098 crank in.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

What about when running a supercharger DrMini ?

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No more Minis!......For now.

Supercharger is 'on' alot earlier so you wont have the same lag... but still a bit

Kev, that just means ill have to hold the pedal and keep the revs at about 3000rpm before I let the clutch out... rofl... oh this is going to be one fun motor... (ill have plenty of orange clutches spare hehehe)

Pete.

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Click here for the Turbo Conversion Thread!

Sorry to hijack but... Any thoughts as to how much boost is safe to run with 8.5:1 CR. 8psi? 10psi??? 12psi??

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Carl
Previous Owner & Driver of 1 Morris "It's not a Cooper!!" 850

The answer is 'it depends'
Which part will 'break' first?

Usually head gasket... if that holds, pistons collapse? etc...

Pete.

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Click here for the Turbo Conversion Thread!

Yeah, i know the story. Just wondering if anyone had experience with boost levels at certain comp ratios...

I don't think my boost is excessive... We'll soon see

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Carl
Previous Owner & Driver of 1 Morris "It's not a Cooper!!" 850

Carl,

Metro Turbo engine has 9.4:1 compression standard. People in the UK are running up to 10psi with that but no more. (I love to state this fact when some people sau 9:1 is the limit for 7psi...well nah it's not! But it's the overall setup that makes it's ok to run larger compression.)

Metro Turbo motor has strong pistons to take the abuse and fancy exhaust valve to keep the heat down (I think).

So really 8.5 should be able to go beyond 10psi. Of course if you take my advice and blow you engine up...sorry.

But I reckon you'll be fine. Providing your pistons are up to, your head, and gasket and that you use 98 octane ertrol always.

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1964 Morris 850, 1330 Supercharged - 81.8hp atws.
1975 Leyland Mini S 1100S powered - Nice and reliable.
1977 Leyland Mini LS - Project LS-T

7.5:1 compression ratio, with 21psi boost at full noise on lown blown. Pulled well from idle, went like stink over 3500rpm.

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1970 Cooper S ex-Bathurst & ATCC
1964 Austin Cooper S ex-Group C race car
1967 Morris Cooper S ex-Group B
1962 Mini Speed sports sedan
1968-71 ex-Peter Manton Shell car

i am using 7.6:1 and run up to 18psi, basically as a rule of thumb, 9:1 you can run 10psi or so, 8:1 you can run 14 or so, and 7:1 you can run up to 18psi etc.

anything over 12psi you want an intercooler, strong pistons and good ignition system

Grant

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100% Pure A Series Turbo
Morris - The Original RedBull Racing

i've always used the old schooll method of 8/8/8

8 psi 8:1 cr 8000rpm limit

but if you look at it and add the numbers you get 24

so if you want to run say 10 :1 cr at 8000rpm you car safely have 6 psi

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120bhp with 450kg just fun waiting to happen

We were prob. drunk when we set it up last and thought this will be a good idea

Has anyone thought of adding oil jets under the pistons to cool them? It is a bit fiddly to make but I think it could be worth it.

Most of the UK turbo mini boys who bother with oil squirters just use Ford ones

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Too many cars, and too little time.