Compression Ratios ???
Turbo Mini Forums

just wondering guys what compression ratios CCs & maximum boost everones running with or without intercooler.

mine is 8.4:1 intercooled 10 to 12 psi boost 1275cc.

thanks

Edited by BENROSS on 9th Feb, 2006.

about 8:1 10 psi no IC


or about 7.5:1 18 psi fairly big IC

Alex

AlexF

Not sure about my CR really.. i was aiming for 8.5 but that may have changed. 1293cc, 12.9cc piston dish with 26cc out of the head.. anyone care to work it out for me?

Its not set up yet, so i can't really drive it, but i have seen well over 10 psi a couple of times.. scary really.

2wd cossie intercooler.

www.afracing.com/cr.xls

When you getting it sorted Alex?

Alex

AlexF

Never! ha ha. Seriously, as soon as I can afford it.. March maybe..

edit: that doesnt really help as i dont know what values to put where.. :)

I dont care. I'm going to run 15psi and I'm fairly sure it can take it :)

Edited by AlexB on 9th Feb, 2006.

well if you want it setup in the mean time for free....

my previous offer still stands!

Alex

AlexF

8.3-1CR 14psi intercooled 1380cc.

AlexB i make your cr 8.75-1 calculated that your pistons are flush with the block deck at tdc and 2.8cc head gasket volume.

-MINI CLUBMAN 1380 TURBO-

i'm running 8:1 CR, 1293cc. boost is 7psi at the minute, when i've rebult me carb i'll go have it setup for 15psi though. thats with a 2wd cossie cooler aswell.

8:1 i think, and have run upto 16psi with a lancia delta intercooler

i would like to play with a higher comp, lower boost engine and see what that is like

8.3:1, 18psi, Izusu Trooper intercooler (998). << how's that happend when I tried to write 998 in brackets? I never use emoticons, it's not my style.

different turbo, CR, Intercooler and head on new engine. Will still try to run 18psi

Wil

Edited by wil_h on 9th Feb, 2006.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

9-1 comp 10psi with med size intercooler ms edis ignition
10,000 reliable miles used every day.

http://www.rabdunn.co.uk/

9.4 to 1 running 10 psi on a rs ruscort intercooler.

always looking for them bigger bunches of bannanas

1998 to 2001 ran 9.3 :1@ 4 psi no intercooler. reliable 20k miles..2005 rebuilt 8:1 using omega pistons boost will be 15psi .intercooler probably.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

up to press the average CR ratio is 8.46:1
the average boost is 12.5:1

and the genrall concensus is the best performing cars run on a CR ratio of 8.2:1
and an average... ish boost of 16psi intercooled

any more chaps

anyone running under 7.5:1??? including boost pressure & Bhp.
or know of any one?

Edited by BENROSS on 10th Feb, 2006.

Mine is a shade below 8:1.

It remains to be seen what power it will make.

another intresting question/poll would be to ask what fuel people use with their set up!

The reason we run the boost and CRs we do is linked directly to the fuel we can buy.

Alex

AlexF

what pistons are you running Nic? remember you sayin they were a standard piston dished out in a previous thread?

Edited by Brocky on 8th Mar, 2006.

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

https://www.facebook.com/groups/17557298589...096464253807802

Sounds good

Will get back once I have all info together, may be tonight after work

Many thanks

Edited by Brocky on 8th Mar, 2006.

BTW - I took my buddy VTEC Pete out for a spin this weekend, and even though I am running her in, he gave it a name, the "Brocket"...cause I'm a brocket maaannn, nah nah nah nah nah nah nah nah nah nah nah....

Build thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=7483

Katy Mini Owners Club Thread - http://www.turbominis.co.uk/forums/index.php?p=vt&tid=505552

Let's make sure you embarrass at least one VTEC MINI today !

https://www.facebook.com/groups/17557298589...096464253807802

Hi Chaps,
Have just been searching through old threads and have found this.

Im running a vmax scart supercharged mpi and am currently having the engine rebuilt using the Omega forged FIS pistons with the 18cc disc. Bore will be +20 so 1293 and crank is standard but is being hardened.

What is the optimum compression ratio for this and what size should the chambers be in the head if i use a Bk450 gasket without decompression plate. The cam i have is an SW5i with 1.5 full roller rockers and will be using 97 ron fuel but i can addpro boost if required.

I cant run an IC as there is just no room but will be fitting one of the vmax charge casing coolers.

Im pretty sure that the standard boost from the charger is 10psi but i can up this with a smaller pulley if needed.
Cheers for the help
Andy

Edited by Andy500 on 4th Apr, 2008.

I'd aim for around 8.3:1 its a good compromise on and off boost so I would think it would also well on a super charged setup.

Depending on how efficient your charger is you may get away with 12PSI. The thing is you get to a point where you run more boost but because the air heats up more you don't gain any extra power

Have you considered fitting a Charge cooler instead of fitting an air to air intercooler?

Edited by matty on 4th Apr, 2008.

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

Mine is 8.2 planned boost is a lot higher than 18psi with a charge cooler

JK

If Carling made Mini engines
it would probably be like this one!

Thanks for the info chaps. Johnk are you running an m45? where did your charge cooler come from? or did you make it yourself?
Cheers
Andy

I think the answer to your question can be found in the 18psi reference... An Eaton is pants much over 12psi.

I don't even remember what my CR is now... :( Think its 8.4:1

my compression ratio is 8.5 to 1 and i run a safe 15psi, with a few tweaks i recon it could be taken to 18+ psi and still be safe.