Concerns about Supertech pistons - Page 3 - 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 08-24-2009, 12:48 PM   #41
Elite Member
iTrader: (2)
 
Join Date: Jan 2007
Location: Los Angeles, CA
Posts: 8,782
Total Cats: 119
Default

Quote:
Originally Posted by spoolin2bars View Post
. anyway's why are you running 20psi?
What the **** is wrong with you? Isn't your username "spoolin2bars"? Did you know 2 bars is almost 30psi?
Faeflora is offline   Reply With Quote
Old 08-24-2009, 01:46 PM   #42
Senior Member
iTrader: (1)
 
Join Date: May 2008
Location: south texas
Posts: 1,419
Total Cats: 9
Default

it's spoolin2bars is because of my galant vr4. and i wouldn't run that much at a trackday in it either. just seems like alot of abuse for not a big difference in lap times on most tracks. on the street or drag track, with sticky *** tires it makes sense. i would rather keep it safe/simple and run a trackday event, than be working on my car or spending money on replacement parts.

Name:  mepca1.jpg
Views: 88
Size:  91.2 KB

Name:  IMG_9676.jpg
Views: 88
Size:  36.8 KB
spoolin2bars is offline   Reply With Quote
Old 08-24-2009, 03:13 PM   #43
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

To each his own. I like having the power myself, and it is a lot of fun on the track too.
Fixing broken motors does suck though, but I am working on adding margin back. I suspect in this case the problem was caused by bad WI distribution into the #1 cylinder due to the manifold design. I am switching to port injection and better flow regulation.
ZX-Tex is offline   Reply With Quote
Old 08-24-2009, 10:04 PM   #44
Senior Member
iTrader: (1)
 
Join Date: May 2008
Location: south texas
Posts: 1,419
Total Cats: 9
Default

i would love to have that much power too. but i can't sacrifice reliability for it. especially since i drive my car to all events still. hopefully i'll have a tow rig soon so i can push it harder. i think i will be running a little more boost for tws though. 11psi is 238whp so 12psi should get me to 250whp or so.
what about race gas? if your WI isn't flowing evenly throw some motorsport 104 or higher in there. then you don't have to count on the WI to save your motor. anyway's good luck with the new pistons. i'm dying to see what 300hp does out there.
spoolin2bars is offline   Reply With Quote
Old 08-24-2009, 10:38 PM   #45
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by spoolin2bars View Post
i would love to have that much power too. but i can't sacrifice reliability for it. especially since i drive my car to all events still. hopefully i'll have a tow rig soon so i can push it harder. i think i will be running a little more boost for tws though. 11psi is 238whp so 12psi should get me to 250whp or so.
what about race gas? if your WI isn't flowing evenly throw some motorsport 104 or higher in there. then you don't have to count on the WI to save your motor. anyway's good luck with the new pistons. i'm dying to see what 300hp does out there.
Its ******* ridiculous. Reeling-in C6Z's, porsches, and just about anything under the sun is hilarious. When you make that kind of power, with decent suspension like Flex, and R-comps...there are no more excuses. FTD or tuck your tail.
hustler is offline   Reply With Quote
Old 08-24-2009, 10:38 PM   #46
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

I'm working on failsafe schemes, with some redundancy, for the WI in case it fails. But at the track, yeah using some higher octane fuel as a safeguard is probably a good idea.

I am also shopping for a cheap car trailer and when I get one will start towing with my truck to track events. That is what I do with the race bike now. It is nice knowing that no matter what happens, short of injury (a risk with motorcycle racing) that you can still get home. If I ever seriously got into car racing, I would build a track car. Ugly but fast, just like the race bike.

That being said, I would have driven home from MSR-C with no problems after running the motor HARD (at 14-20 psi) in several sessions with no problem had it not been for that piece of teflon tape. That was the root cause, not the track time. And I still got home even with a trashed turbo.

Last edited by ZX-Tex; 08-24-2009 at 10:57 PM.
ZX-Tex is offline   Reply With Quote
Old 08-24-2009, 10:47 PM   #47
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

Quote:
Originally Posted by ZX-Tex View Post
I'm working on failsafe schemes, with some redundancy, for the WI in case it fails. But at the track, yeah using some higher octane fuel as a safeguard is probably a good idea.

I am also shopping for a cheap car trailer and when I get one will start towing with my truck to track events. That is what I do with the race bike now. It is nice knowing that no matter what happens, short of injury (a risk with motorcycle racing) that you can still get home. If I ever seriously got into car racing, I would build a track car. Ugly but fast, just like the race bike.

That being said, I would have driven home from MSR-C after running the motor HARD (at 14-20 psi) in several sessions with no problem had it not been for that piece of teflon tape. That was the root cause, not the track time. And I still got home even with a trashed turbo.
I know what you mean. On that track day I realized that my car isn't one you want to screw up in. With the new set-up I plan on running it at 10psi because I enjoy life. I need a cage for the way i drive out there.


I'm going to tune on 91-octane and run 93. Safety is win.
hustler is offline   Reply With Quote
Old 08-24-2009, 10:49 PM   #48
Elite Member
iTrader: (12)
 
Join Date: Aug 2006
Location: Central-ish VA
Posts: 4,449
Total Cats: 16
Default

So, by chance are we ever going to see pics of these failed pistons...
neogenesis2004 is offline   Reply With Quote
Old 08-25-2009, 12:36 AM   #49
Elite Member
iTrader: (15)
 
Join Date: Sep 2007
Location: Incline Village, NV
Posts: 2,073
Total Cats: 5
Default

FWIW my JE pistons are about 4.5mm from the valve pocket to the end of the piston. Will post pictures in a few min.

Name:  -1-3.jpg
Views: 87
Size:  63.0 KB

Last edited by thesnowboarder; 08-25-2009 at 01:12 AM.
thesnowboarder is offline   Reply With Quote
Old 08-25-2009, 01:55 AM   #50
Cpt. Slow
iTrader: (25)
 
curly's Avatar
 
Join Date: Oct 2005
Location: Oregon City, OR
Posts: 12,107
Total Cats: 518
Default

Dear Lord, are those plastic calipers? +/-.005?!?
curly is offline   Reply With Quote
Old 08-25-2009, 03:36 AM   #51
Elite Member
iTrader: (15)
 
Join Date: Sep 2007
Location: Incline Village, NV
Posts: 2,073
Total Cats: 5
Default

Quote:
Originally Posted by curly View Post
Dear Lord, are those plastic calipers? +/-.005?!?
yea they are crap, but its better than nothing. I'm not measuring oil clearances with them
thesnowboarder is offline   Reply With Quote
Old 08-25-2009, 09:35 AM   #52
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

What bore piston is that?
ZX-Tex is offline   Reply With Quote
Old 08-25-2009, 10:09 AM   #53
Tour de Franzia
iTrader: (6)
 
hustler's Avatar
 
Join Date: Jun 2006
Location: Republic of Dallas
Posts: 29,114
Total Cats: 351
Default

again, who tuned this car on the dyno? Did you use det-cans?
hustler is offline   Reply With Quote
Old 08-26-2009, 01:45 PM   #54
Elite Member
iTrader: (15)
 
Join Date: Sep 2007
Location: Incline Village, NV
Posts: 2,073
Total Cats: 5
Default

Quote:
Originally Posted by ZX-Tex View Post
What bore piston is that?
84mm

Quote:
Originally Posted by hustler View Post
again, who tuned this car on the dyno? Did you use det-cans?
My car? Sav, yes det-cans were used and there was no knock. Rod failure.
Name:  CRW_9834.jpg
Views: 88
Size:  95.8 KB
thesnowboarder is offline   Reply With Quote
Old 08-26-2009, 03:09 PM   #55
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

Same thing happened to me with my stock motor.
ZX-Tex is offline   Reply With Quote
Old 08-27-2009, 11:24 AM   #56
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

Dropped the motor off at the machine shop this morning. I should have pictures of the pistons in about a week.
ZX-Tex is offline   Reply With Quote
Old 08-27-2009, 11:51 AM   #57
Senior Member
iTrader: (1)
 
Join Date: Sep 2006
Posts: 738
Total Cats: 86
Default

BTW, we just took apart a race motor with similar piston damage in a very short timeframe, and I took another look at the 11:1 "Spec Miata" piston on my desk. It's just how a piston gets hurt from detonation. The rod bearings on the race motor were also hammered badly, so you might want to check those out. And definitely get the car tuned.
Keith@FM is offline   Reply With Quote
Old 08-27-2009, 11:53 AM   #58
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

Yep, agreed. I asked the engine builder to check out the motor including the bearings. Definitely going to get it tuned too, and am adding port injection on the WI, and some failsafes.
ZX-Tex is offline   Reply With Quote
Old 08-27-2009, 05:40 PM   #59
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,366
Total Cats: 1,327
Default

Quote:
Originally Posted by thesnowboarder View Post
My car? Sav, yes det-cans were used and there was no knock. Rod failure.
This is what happens when you think a motor has forged rods, so you tune to 17psi, and then find out it has stock rods.
Savington is offline   Reply With Quote
Old 09-16-2009, 11:31 PM   #60
Elite Member
Thread Starter
iTrader: (15)
 
Join Date: Dec 2007
Location: San Antonio, Texas
Posts: 4,889
Total Cats: 28
Default

OK, finally, the moment you have all been waiting for...
Click here for pictures of the damaged piston

A preview...


The machine shop finished reassembling the motor and I picked it up today, along with the old pistons. There are definitely signs of detonation. Check out that bent up chunklet that is barely hanging on, with the crack running through the cantilever end. I saw that in the borescope, and it was clear it was time to park it and pull the motor

The rod bearings were also damaged, specifically the top portion (where the rod presses the bearing into the crank during the power stroke). Everything else was OK, including the head. The rest of the pistons look fine, just some carbon buildup. Amazing how well it was still running despite this damage. No oil smoke, no noise, nothing. If I had not pulled the plugs out to regap them I would have never known, at least not until that chunk broke loose.

On a positive note, one of the head guys at the engine shop, Donald Duffin (Duffin Engine, one of three brothers that owns/runs the shop) had a great story about a trip he took to Barber Motorsports Park; I was out there last week. We were talking about how incredible the museum is (if you are in Alabama, you MUST go). He had a great story about getting to meet George Barber himself, and getting a tour from him of some of the otherwise restricted areas of the museum. Great stuff.

We need to have a Miata Challenge at Barber. A Miata would be a blast on that track, even better than Hallett.

Last edited by ZX-Tex; 09-16-2009 at 11:48 PM.
ZX-Tex 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 58 12-13-2017 10:04 PM
OTS Bilstein to motorsports ASN conversion stoves Suspension, Brakes, Drivetrain 5 04-21-2016 04:00 PM
WTB Stock NB Pistons pdexta WTB 0 09-28-2015 12:18 PM
built motor parts all new! Shortpersonbk Miata parts for sale/trade 3 09-12-2015 12:39 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 08:38 AM.