engine number vs compression ratio?
Turbo Mini Forums

Hi peeps

My first qestion, and i hope is has not been discused before ( or i've missed it) and that tis is in the correct place on the forum.

My 1991 mini 998 has the following engine number: 99H997P 145388. known to be its seccond engine.

i read in my hanes manual that the 998 engines had verious CR's but can't seem to fined witch CR my engine has.
1989> low compression 8,3:1
1989> high compression 9,6:1

lower compression is more boost possible correct?

Can enybody shed eny light on this or point me in the correct direction.

Thanks, Andrew

Cheers, Andrew

______________________________________________________
Little car Little power........... For now That is!!!!!

1983 mini down paid, must collect soon and get welding!
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http://www.guess-works.com/Gearbox/Technic...=P&EN_NO=145388

a good place to start, although it states you have the "first alternative compression ration" lol and a 2.9diff

Yes i moved to the darkside

Instagram @jdm_brett

99H/997 1980 onwards A+ block, flat top psitons, economy fitment with 2.95 final drive
99H/997 From engine number 127422 with 2.95 final drive
from memory the 99H- means high comp anyway

info from - http://www.minimania.com/MM/Engine___Ident...ata_UPDATED.htm

so shout at them if its wrong

Edited by Brett on 25th Mar, 2009.

Yes i moved to the darkside

Instagram @jdm_brett

Hi Brett, thanks for that, aleast now i have some info on the engine.
2.9:1 diff ratio thats good or bad? ie will it go fast and be slow of the lights or be quick of the lights an have a limited top speed. I hav nevver driven the car on the road yet.

now to fined the compression ratio.

Cheers, Andrew

______________________________________________________
Little car Little power........... For now That is!!!!!

1983 mini down paid, must collect soon and get welding!
______________________________________________________

being a 998 it will feel sluggish off the line but will cruise on the motorway nicely and give half decent fuel economy the lower the first number the higher the gearing the faster top speed

Yes i moved to the darkside

Instagram @jdm_brett

Ehh.... yep that was a dumb qestion of mine :$ as i have modded a number of Landrover diffs in the past to compensate for larger tyres.

I may have found new unused 12g295 head, wil i still need new pistons? 295 has 28 cc chambers correct?

i am looking for 150 bananas or so in the end but wan't to be able to return the engine back to original so rather not need to pocket the blok.

Cheers, Andrew

______________________________________________________
Little car Little power........... For now That is!!!!!

1983 mini down paid, must collect soon and get welding!
______________________________________________________

150 from a 998 is quite hard core tbh i would be changing most things, wil_h on here runs a hill climber 998 turbo and many years development to get not much over 150 brake have a look at his engine specs im going to dig out some links for you to read through :)

Yes i moved to the darkside

Instagram @jdm_brett

Turbo phils site has a good link to howto build a 998 turbo written by wil_h a good source for general info too...
Click Here

and wil_h ' site ast time i looked on there there was a spec list
Click here

just thought my 998 i stripped down was the high compressin engine and had flat top pistons, other than that i dont know i think wil_h ended up with it

Edited by Brett on 25th Mar, 2009.

Yes i moved to the darkside

Instagram @jdm_brett

Cheers for the links, i had them book maked allready, but have now read both sites top to bottem.

I had evry intention to beef up as mutch as i can dispite cost , if i ain't got the dosh, the project will go on hold till i do
I hav cut the corners and been to money minded on the part restouration ov my current rangerover, it in the state its in now will fail its mot coming august, all becouse i cut corners on som parts and decent rust prevention, and now i am kicking my self for it.

Cheers, Andrew

______________________________________________________
Little car Little power........... For now That is!!!!!

1983 mini down paid, must collect soon and get welding!
______________________________________________________

yep know how that feels mate, this mini im rebuilding and turbo charging, is the second time in 4 years its been rebuilt and this will be the second time in 2 years i have turbo charged it,

if its worth doing, its worth doing right...

Edited by Brett on 27th Mar, 2009.

Yes i moved to the darkside

Instagram @jdm_brett