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andeh

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982 Posts
Member #: 97
Post Whore

Near Daventry, midlands

1st Jun, 2005 at 02:23:20pm

what pistons do people run in 998 turbos? I cant make head nor tails of the minispares site as regards to pistons. I know 998 pistons are a bit hit an miss at the moment due to availability problems (afaik), so was thinking of getting a set now rather than later.

Anything else worth doing to the bottom end other than the manditory crank/damper/flywheel balance and heat treat the crank?

I've seen the future and tbh its Pie


snowfruit

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321 Posts
Member #: 557
Senior Member

Ireland

1st Jun, 2005 at 03:10:12pm

Do you have a URL for the manchester mini site?

http://mini.twisted-design.net/blog/

wil_h

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9258 Posts
Member #: 123
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Betwix Harrogate and York

1st Jun, 2005 at 03:12:32pm

I would totally agree with all of that ^^^^^ if it wasn't for the fact that the later slipper-type pistons didn't last very long in my engine. the ringlands just collapsed. I was running 18psi, but I still do now.

I've been using the earlier circlip-type piston for a few years now and they are still in good condition, if using these I would suggest fitting the nylon buttons as the circlips always fall out.

There are forged pistons available, and these will be going in my new engine.

Wil

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



On 2nd Jan, 2013 fastcarl said:
the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


wil_h

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9258 Posts
Member #: 123
Post Whore

Betwix Harrogate and York

2nd Jun, 2005 at 06:14:00am

I can't say what caused the pistons to break, but I didn't change anynthing else on the car when I put the other pistons in and they have survived 3 seasons.

I have used the slipper pistons without failure for thousands of miles without a turbo and never had a problem, so I still don't really understand why they broke.

Our map is here http://www.turbominis.co.uk/forums/index.php?p=vt&tid=3734

If you look at it we still run 25 deg advance at full boost and more as the boost is rising. I would advise starting with a slightly retsrded version of this map as the RR guy was amazed our car didn't pink at all.

Wil

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



On 2nd Jan, 2013 fastcarl said:
the design shows a distinct lack of imagination,
talk about starting off with a clean sheet of paper, then not bothering to fucking draw on it,lol

On 20th Apr, 2012 Paul S said:
I'm mainly concerned about swirl in the runners caused by the tangential entry.


AlexF2003

5795 Posts
Member #: 80
AFRacing LTD

Newbury, Berks

2nd Jun, 2005 at 12:45:43pm

On 01/06/2005 14:53:22 mini1071s said:
I am using the stock A+ pistons on the basis that it's rpm that kills them, not increased cylinder pressures as such as long as temperatures are kept to sane levels with a good intercooler.



Two diffferent points in there!

1) det kills pistons...

but so does rpm and cyllinder pressure!

2) det is promoted by high air charge temps, hence intercoolers!

Alex

AlexF

andeh

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982 Posts
Member #: 97
Post Whore

Near Daventry, midlands

2nd Jun, 2005 at 05:54:00pm

some interesting stuff there, i know the slipper type are becoming hard to get hold of so i might grab myself a set now to give me more options. Who are making and/or distributing the forged 998 pistons? ive never heard of them (not that i've looked into building 998's before)?

Edited by andeh on 2nd Jun, 2005.

I've seen the future and tbh its Pie

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