Safe Rev Limit
Turbo Mini Forums

Right, now that I've put the turbo on the 998, I keep hitting the rev limit.

I originally built the engine for mpg, but having been under the bad influence of TM, I find myself ragging the poor engine at every opportunity :$

I've got the Minispares/Hypatec P20950 pistons with circlips.

Because of the circlips, I've limited the revs to 6k.

Am I being overly cautious or is 6k right?

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Did you fit buttons to stop the clips getting out?

If NOT, then I'd say stick to 6k. In my youth the first vaguely performance orientated engine I ever built was a +20 1098cc A series, with a piper 270 cam, and a skimmed 12G295. With a centre main strap and a vernier timing gear set it cost me the bulk of my then meagre part time wages over about 8 months. I revved it to 6500rpm like the young 18 yr old hoodlum I was and it lasted about another 8 months before a circlip got out, and scored the bores to pieces, knackering it.

mini se7en's rev to 10,000 if thats any help!

6 sounds very low, i'd have gone with 7 or 8 depending on the build

No buttons I'm afaid.

I'll stick to 6k until it comes out, then I'll fit some buttons.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

A 1098 will have higher piston speeds and acceleration than a 998. I would think that would be significant enough to mean that 6.5k on a 998 would still be safe.

Jean

http://www.jbperf.com/

Everything else will be fine other than the circlips. TBH if they are new then the chances are the occasional sprint to 6,5K wont shorten their life in the short term.

I rev my 70k 998 engine to 7k when in a hurry but 5.5 is the usual. It is standard with pushfit slipper pistons.

As I mentioned at Avon, if I limited mine to 6k it wouldn't have done a 16second 1/4.

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

www.twin-turbo.co.uk

stick with 6 Paul.

i just checked out the piston g's and speeds,

you only need to turn a 998 an extra 750 rpm to get to the same piston speed and g's. i was suprised at that.