Low vs. High silicon pistons. Also Diamondyzing. - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Engine Performance This section is for discussion on all engine building related questions.
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 06-04-2013, 08:02 PM   #1
Tea of the Sea
Thread Starter
 
StarletRick's Avatar
 
Join Date: Apr 2010
Location: Essex, UK
Posts: 113
Total Cats: 4
Question Low vs. High silicon pistons. Also Diamondyzing.

Guys,

I'm in the throws of finishing my shopping list for my build, and am at a fork in the road with piston choice.

CP or Supertech?

I've read TONS of info/posts detailing the differences, but I'd like people to chime in with some real-world (sexual) experiences.

I'm aiming for about 350hp in an ultra-reliable road/track car, and at the minute I'm leaning towards the ST's due to the more "daily" nature of the high silicon pistons. Am I missing a trick? Is there something super awesome I've missed about the low silicon pistons, considering my application?

Also, to steer this away from an OMG SEARCH NOOB replies - I'm thinking about having them Diamondyzed. Admittedly this is about 20% because it looks awesomesauce and might be epic and 80% because I can have them pink ^^. I've yet to see anyone mention it here. Let's discuss.

http://www.techlinecoatings.com/hi-p...iamondyze.html

Last edited by StarletRick; 06-05-2013 at 05:10 AM. Reason: added URL
StarletRick is offline   Reply With Quote
Old 06-04-2013, 08:22 PM   #2
Elite Member
iTrader: (2)
 
Join Date: Aug 2012
Location: Indianapolis
Posts: 3,325
Total Cats: 235
Default

Diamondyzed:

wtf does this do that the teflon coating already on the STs doesn't?
thenuge26 is offline   Reply With Quote
Old 06-04-2013, 08:25 PM   #3
Elite Member
iTrader: (1)
 
Leafy's Avatar
 
Join Date: Jun 2012
Location: NH
Posts: 9,093
Total Cats: 90
Default

The high silicon pistons should be better in a streeted car since they can use smaller piston to wall clearances. However they arent as strong as the other alloys. I'm not too familiar with the ST alloy but some High Si Al alloys are quite abrasive which would mean that theoretically you'd have increased cylinder wall wear on the thrust side.

I have super techs in my engine. I have no idea if they were hand finished. But if I was going to re-do the build myself they would get hand finished since the pistons come with some sharp edges as delivered. Theoretically the 949 pistons are going to use the same alloy but with better piston top geometry I have no idea if it will be worth the price difference vs hand finished ones.

Coating wise. The more I learn about piston coatings the less I'm able to decide if I like them or not. DFL on the skirts seems like a good idea in theory, in practice it seems to wear off quickly. Thermal coating on the piston tops seems like a good idea in theory, or it seems like a bad idea in theory, either way it seems to wear off. DFL on the rest of the bearings in the engine, I've been told by a couple different spec miata builders that it isnt worth any power at all (you know they tested it, its spec miata), but if you suddenly loose oil pressure with DFL if you instantly kill the car and push in the clutch you might be able to salvage the engine without any rebuild.
Leafy is offline   Reply With Quote
Old 06-04-2013, 10:43 PM   #4
Senior Member
iTrader: (1)
 
Join Date: Mar 2008
Location: Cromwell CT
Posts: 1,107
Total Cats: 48
Default

Brian Crower steered me away from having a thermal barrier coating put on some 4G63 pistions (1000hp build) . They said the coating causes the rings to overheat
ctdrftna is offline   Reply With Quote
Old 06-05-2013, 03:25 AM   #5
Tea of the Sea
Thread Starter
 
StarletRick's Avatar
 
Join Date: Apr 2010
Location: Essex, UK
Posts: 113
Total Cats: 4
Default

That's an interesting view. What was you thinking of coating them with? The diamondyze is only about 10% efficient as a barrier so it isn't at all a total heat blocker.

I was actually thinking about it to help the rings. There would be no degradation around that area as the process makes the alu super tough and corrosion/wear resistant.

Interesting about the DFL too, I was thinking about using this as I'd heard good reports! I may still have a go for the money involved - it isnt expensive.

Last edited by StarletRick; 06-05-2013 at 05:11 AM.
StarletRick is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 59 Yesterday 09:00 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
WTB 90-97 miata low profile headlight kit DonPlatt WTB 0 09-25-2015 03:57 AM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 05:34 AM.