metro van pistons for tubo use ???
Turbo Mini Forums

hi everyone
i have a 1989 mg metro engine for my turbo prodject (12hd24) which i believe is high comp unleaded (10.5.1)
first of all i cant find any info on how that particular comp ratio is achieved... is it with smaller chambers (i.e. less than 21.4cc) or is it as i suspect the pistons ?
secondly checking through the metro engines spec data, i see that the VANS an a few saloons model from 1989 have reported comp ratio's of 8.0.1, that seems like a good comp for tubocharging ???
has anybody got any info or comments on these engines ? i suspect they have shorter or bigger dished pistons ?
the engines i think may be suitable are ...
12hd18....... saloon
12hd19 & 20........ van
12hd 41 &42........ saloon

Hi,
I think you are correct with the pistons being the thing that changes the compression.
As for the van engine I think it has been mentioned on here before, but the concensus was that the pistons wouldn't be up to it.
Your 10.5:1 is too high. People on here have run 10 psi on 9.4:1 with good results.
What you need to ask yourself is what will be the main use for the car? If you think mostly road, then higher compression with lower boost, would be better, even to a certain extent circuit type racing as you'll have less lag coming out of corners......
If you want to drag, then low comp and loads of boost.....
Also when buliding an engine, you want to put good quality parts in it, as one poor component will probaly cost you the engine and g/box when it lets go....
Cheers,
Gavin :)

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All chamber sizes were the same it's just pin height and maybe dish that is varied.

hi there thanks for your replies & comments....
my car is actually running a healthy 1275 with 9.4.1 comp at the mo. I was going to build up the spare metro engine, but now i think i will just get the mg metro head taken out to 26cc chambers & stick it on, it should be spot on ! i have a fairly large intercooler from a passat & Mjlj ignition so should hopefully be able to run 12psi safely......... hopefully ???
any one else running a similar setup, whats the realistic bhp at the wheels it will provide ? any ideas ?
after its RR session @ sanspeed it gives 68bhp @wheels not bad as its std apart from exhaust & intake mods.
thx again

Hi,
Forget BHP, especially when talking turbo engines. Torque is what puts the smile on your face And your gearbox all over the floor!
Cheers,
Gavin :)

VEMs Authorised Installer / Re-seller. K head kits now available!

WB/EGT gauges. Click here for customers write-up

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On 10th of Jan, 2007 at 05:41pm Bat said:
Hi,
Forget BHP, especially when talking turbo engines. Torque is what puts the smile on your face And your gearbox all over the floor!
Cheers,
Gavin :)

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