The only way to control detonation is to avoid it. I don't want to go against what Stewart W Rallying said, but I think the std pistons are good for 20PSI if you avoid detonation. That means you need to have your timing, Air/Fuel mixture ratio and air temperature in control. That means either having your setup dynoed and set up to avoid detonation, especially on the high peak boost you want to run. Or fitting some sort of knock sensor, whether a std knock sensor or a microphone type one, so you know when it is about to detonate and can back off and avoid doing damage.
Water cooling will only help if the problem is caused by after tubo air temps being too high. This will not help if you are running too much advance. If you are not running retard on boost, then 15 deg is too high for 12-15lb. IMHO at 3000rpm with 12 psi you should be running around 4-5 deg of advance MAX, with a good intercooler.
I have a set of pistons from a Z18 where the ring land between the compression rings is broken. It was from excessive boost causing detonation. That must be where the detonation causes failure as the tops of the pistons are like new.
-----Original Message-----
From: mark krawczuk [SMTP:[EMAIL PROTECTED]]
Sent: 21/11/2001 10:17
To: [EMAIL PROTECTED]
Subject: Re: Z18 questions
hi,� i talked to stewart w ralling and he said the pistons would be good for 12 lb.( and i was running 15�lb for about 5 mins�) and stewart also said that� it was dentonation�
�
�
�i also �phoned up a turbo place in nsw, and he� said it was dentonation.
�
the two� pistons looked absolutely� fine
, besides the cracked� lands, no sign of any other damage.
�
�
�
��� any ideas on how to� controll dentonation? the dizzy was modified for 15 degrees, with engine idling and� vac line disc, and a total of 20 degrees.
i have a inter cooler, would water inject be a good idea?
�
�
�
������� mark k
�
----- Original Message -----
From: Rowe, Adam <mailto:[EMAIL PROTECTED]>
To: [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
Sent: Wednesday, November 21, 2001 9:17 AM
Subject: RE: Z18 questions
Are you sure it was the boost, and not the detonation, that broke the ring lands?
-----Original Message-----
From:�� mark krawczuk [SMTP:[EMAIL PROTECTED]]
Sent:�� 20/11/2001 20:48
To:���� [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
Subject:������� Re: Z18 questions
hi,� steve t are u using factory z18 turbo pistons, what� boost are u running?
�
the ring land below 1st ring� is cracked,� stewart w ralling said that� i was running too much boost (15 lb)
�
�mark k
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