Bally 4 Posted May 15, 2007 Have recently pulled down my Mi16 Turbo project in order to lower the compression. It was way too high to really push the turbo , What compression would I achieve by using the 8 valve pistons in the 16 valve engine and would the valve clearance be enough or should I duct the pistons Share this post Link to post Share on other sites
Revla 2 Posted May 15, 2007 Have recently pulled down my Mi16 Turbo project in order to lower the compression. It was way too high to really push the turbo , What compression would I achieve by using the 8 valve pistons in the 16 valve engine and would the valve clearance be enough or should I duct the pistons From memory, turbonicky did this (doesn't log on to the forum much). PM him and I'll try to get him to write back........ Share this post Link to post Share on other sites
dee205 3 Posted May 15, 2007 Not really answering your problem but have you considered a decompression plate like the DP-Engineering ones? Damien Share this post Link to post Share on other sites
petert 585 Posted May 15, 2007 I can't believe you'd even entertain the thought of using 8 valve psitons. They're so wrong for so many reasons: - too heavy - wrong pin size - not full floating - no valve reliefs - cast - too heavy - too ugly Either face down the existing pistons to DFW specifications, or use a de-comp plate, or better still, buy some new forged pistons. Share this post Link to post Share on other sites
pdd144c 0 Posted May 16, 2007 I'd buy forged items if funds allow. Share this post Link to post Share on other sites
Henry Yorke 269 3 Cars Posted May 16, 2007 - too ugly pmsl! Don't you just hate ugly pistons. Everyone notices them! It is like a chav having a massive boil on the end of his nose! Share this post Link to post Share on other sites
Bally 4 Posted May 16, 2007 Thanks for the rply, thats why I asked to get reasons why to use them or not to use them. Okay I will skim the std iotems then Thank you. Share this post Link to post Share on other sites
dee205 3 Posted May 16, 2007 Is skimming the pistons going to be safe? What ratio do you need to run for a turbo'd Mi and how much would you need to remove from the pistons. Damien Share this post Link to post Share on other sites
petert 585 Posted May 17, 2007 The DFW and D6C pistons come from the same casting. The crowns are faced off to different heights. The valve pocket depths are relative to the gudgeon pin, not the top of the piston. So you get the same piston-valve clearance with either piston. The DFW is 9.5:1 and has a crown approx. 0.200" thick, with a compression height of 36.28mm. Provided you kept boost to 10psi max. and didn't go any thinner on the crown, you'd be fine with that spec. Share this post Link to post Share on other sites
Bally 4 Posted May 17, 2007 So I need to skim the std piston by how much, I have the D6C piston. Share this post Link to post Share on other sites
petert 585 Posted May 17, 2007 So I need to skim the std piston by how much, I have the D6C piston. 37.12-36.28 = 0.84mm Share this post Link to post Share on other sites
Guest hassan Posted November 4, 2007 So I need to skim the std piston by how much, I have the D6C piston. why not to use the xu7 pistons where its KH is 33.3 mm which will reach about 7.25 compression ratio and you can boost up to 17 psi reliably or i think more but with good managment. Share this post Link to post Share on other sites
