TSE EFR NB2 Build Thread - Page 3 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 11-02-2016, 12:52 AM   #41
Senior Member
Thread Starter
 
Join Date: Sep 2015
Location: San Jose, CA
Posts: 723
Total Cats: 24
Default

Quote:
Originally Posted by codrus View Post
Technically, in order to reuse rod bolts you need to have the measurements from before they were torqued, so that you can re-measure them and determine if they've stretched beyond their elastic limit. I think machine shops will usually give you the measurements when they assemble a motor for you (dunno, I've done it myself the two times I've built bottom ends), so you might ask the PO if he's got a set of measurements. Hopefully you've got it marked as to which bolt came out of which hole in the motor?

If not, then you're taking a risk by reusing them. I think rod bolt failures are usually due to tensile loading rather than compressive loading, and detonation is more about compression, so that would argue that as long as they were torqued properly (ideally with a rod bolt stretch gauge, not a torque wrench) they should be fine.

--Ian
Well ****...
MiataMan00 is offline   Reply With Quote
Old 11-02-2016, 01:16 AM   #42
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 13,799
Total Cats: 1,016
Default

I tried to reuse rod bolts once. I pulled the recorded stretch specs from my assembly notes, measured each one again to verify, and then started disassembly. The fourth rod bolt came out 0.0005" stretched. Had to throw the whole set away anyway.

Fresh ARP2000 bolts are $75
Savington is offline   Reply With Quote
Old 11-02-2016, 01:19 AM   #43
Senior Member
Thread Starter
 
Join Date: Sep 2015
Location: San Jose, CA
Posts: 723
Total Cats: 24
Default

Quote:
Originally Posted by Savington View Post
I tried to reuse rod bolts once. I pulled the recorded stretch specs from my assembly notes, measured each one again to verify, and then started disassembly. The fourth rod bolt came out 0.0005" stretched. Had to throw the whole set away anyway.

Fresh ARP2000 bolts are $75
I know they aren't expensive, but its still money I could have saved. Is 0.0005" really going to effect anything? That seems negligible?
MiataMan00 is offline   Reply With Quote
Old 11-02-2016, 01:36 AM   #44
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 13,799
Total Cats: 1,016
Default

Any stretch at all means the bolt has been yielded and should be changed. Rod bolt failure is the definition of "catastrophic".
Savington is offline   Reply With Quote
Old 11-02-2016, 02:22 AM   #45
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,319
Total Cats: 265
Default

I'll preface this by saying that I'm a software guy, not a mechanical engineer, but here's my understanding:

Metals stretch in two ways -- elastic and plastic. Elastic deformation is like a spring, it deforms in a particular direction under a load and when the load it released it goes back to its original shape. Plastic deformation is a permanent change, when you remove the load it does not return to the original shape. Steel will stretch a small amount in an elastic fashion, and beyond that limit it becomes plastic.

When you torque a bolt, what you are actually doing is stretching it within the elastic range. That's what produces the clamping force, the "spring" of the steel trying to pull the bolt back into its original shape. A torque wrench is only a somewhat accurate way of measuring this because much of the torque goes into overcoming friction. Variances in the cleanliness of the threads, lubrication of the surfaces, etc can change the amount of torque required to get a particular amount of stretch by a fairly large amount.

So when you attach critical fasteners, the best way to do it is to directly measure the stretch of the bolt using a stretch gauge, like this:



The two points go into the dimples on the two ends of the rod bolt and the dial indicator tells you how long it is. For the final tightening you turn the bolt until the length is the specified amount longer than it was at the beginning, typically something like .005-.006 inches. This puts the clamping load into the desired range, but not so high that it plastically deforms the bolt. The rods come with an installation procedure that gives the exact steps for doing this.

Rod bolts need to deal with both static and dynamic loads, though. As the piston moves past the halfway point in the upwards direction it is moving upwards faster than the crank throw. This means that the rod is being stretched by the crank on one end and the piston on the other, and since the rod is in two pieces, all of that stretch is being taken by the rod bolts. This dynamic load is added to the static tensile load that you put on the rod bolts by torquing them, and if that load goes above the elastic limit and into the plastic zone the bolt is permanently stretched and will never be as strong as it was before. When you stretch metal it necks down, becoming thinner and losing some of the strength it needs to resist further deformation. Do that enough times and the rod bolt breaks and boom. If one of the bolts was overtorqued a little bit putting it in (perhaps because the installer used a torque wrench instead of a stretch gauge) then an overrev on the motor may have deformed it.

So yeah, if a rod bolt comes out half a thou longer than it went in, it's junk. If you don't know how long they were before they went in, there's no way to check this because they aren't close enough to each other the factory to go from that spec. I measured mine with a micrometer before they went in, and they ranged between 1.82525 and 1.82735 inches.

--Ian
codrus is offline   Reply With Quote
Old 11-02-2016, 07:20 AM   #46
Elite Member
 
DNMakinson's Avatar
 
Join Date: Jan 2013
Location: Seneca, SC
Posts: 2,112
Total Cats: 196
Default

A yielded part will have considerably lower fatigue limit.

http://www.asminternational.org/docu...81G_Sample.pdf

Long article, but the 2nd paragraph tells the story:

"Fatigue damage is caused by the simultaneous
action of cyclic stress, tensile stress,
and plastic strain. If any one of these three is
not present, a fatigue crack will not initiate
and propagate. The plastic strain resulting
from cyclic stress initiates the crack; the
tensile stress promotes crack growth (propagation).
Careful measurement of strain shows
that microscopic plastic strains can be present
at low levels of stress where the strain might
otherwise appear to be totally elastic. Although
compressive stresses will not cause
fatigue, compressive loads may result in local
tensile stresses." ASM article

Last edited by DNMakinson; 11-02-2016 at 07:43 AM. Reason: Quoted from the long article
DNMakinson is offline   Reply With Quote
Old 11-02-2016, 10:50 AM   #47
Senior Member
Thread Starter
 
Join Date: Sep 2015
Location: San Jose, CA
Posts: 723
Total Cats: 24
Default

Lots of good info here. Thanks guys. I am just going to get new ones because I don't want to risk it. I don't know what the specs were when the rods were new so I can't use them. Oh well.


I got new "premium" front rotors because the stock ones were grooved and just worn out. I didn't get any pics of them due to time (I was in a rush to install everything to to daylight running out, I don't like working in the dark)

I have to say, I am beyond happy with these pads for the street. They dust like stock and are silent, yet the initial bite and overall stopping power is greatly improved. I will surely be buying another set of these once they wear out.

Last edited by MiataMan00; 12-08-2016 at 01:49 AM.
MiataMan00 is offline   Reply With Quote
Old 11-18-2016, 01:09 AM   #48
Senior Member
Thread Starter
 
Join Date: Sep 2015
Location: San Jose, CA
Posts: 723
Total Cats: 24
Default

Any 3" turbo exhaust recommendations aside from Enthusa and FM?
MiataMan00 is offline   Reply With Quote
Old 11-18-2016, 01:13 AM   #49
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 16,270
Total Cats: 1,134
Default

Artech
aidandj is offline   Reply With Quote
Old 11-18-2016, 01:19 AM   #50
Murderator
iTrader: (76)
 
18psi's Avatar
 
Join Date: Apr 2008
Posts: 34,081
Total Cats: 2,176
Default

Or anyone that will build you an exhaust with the "MT special big Maggie"

There is basically nothing better
18psi is offline   Reply With Quote
Old 11-18-2016, 06:43 AM   #51
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 12,847
Total Cats: 871
Default

I thin artech and I are the only ones who will use the big mt.net on an exhaust. I don't regularly build exhausts though. I used an enthuza exhaust for years and was happy with it.
shuiend is offline   Reply With Quote
Old 11-18-2016, 10:49 AM   #52
Senior Member
Thread Starter
 
Join Date: Sep 2015
Location: San Jose, CA
Posts: 723
Total Cats: 24
Default

What is the "big MT.net" thing you speak of?
MiataMan00 is offline   Reply With Quote
Old 11-18-2016, 10:51 AM   #53
Junior Member
 
Join Date: Mar 2014
Location: Jacksonville, FL
Posts: 315
Total Cats: 19
Default

Quote:
Originally Posted by MiataMan00 View Post
What is the "big MT.net" thing you speak of?
the big *** MagnaFlow muffler that's popular here
borka is offline   Reply With Quote
Old 11-18-2016, 10:57 AM   #54
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 16,270
Total Cats: 1,134
Default

Its his *****
aidandj is offline   Reply With Quote
Old 11-18-2016, 11:25 AM   #55
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,132
Total Cats: 836
Default

Quote:
Originally Posted by aidandj View Post
Artech
Quote:
Originally Posted by 18psi View Post
Or anyone that will build you an exhaust with the "MT special big Maggie"

There is basically nothing better
YUS.

If you can't DIY then ARTech is a no-brainer, and the "MT.net Approved Large Body Magnaflow" cannot be beat.

Quote:
Originally Posted by MiataMan00 View Post
What is the "big MT.net" thing you speak of?
https://www.miataturbo.net/general-m...12579-a-84584/



I'm running the 1x579 and its the best thing since the EFR. The other two in the above image are a little easier if you are building an exhaust because the last bend going into the muffler is not as tight, but I doubt it matters that much in the end.
EO2K is offline   Reply With Quote
Old 11-18-2016, 11:34 AM   #56
Ich verstehe nur Bahnhof
iTrader: (3)
 
psyber_0ptix's Avatar
 
Join Date: Mar 2012
Location: Northern VA
Posts: 3,097
Total Cats: 236
Default

Abe said he was taking a break from fab until next year.
psyber_0ptix is offline   Reply With Quote
Old 11-18-2016, 11:55 AM   #57
Junior Member
iTrader: (2)
 
Join Date: Oct 2011
Location: Chicago Il
Posts: 111
Total Cats: 2
Default

The big magnaflow is Great. I ordered mine on Amazon and had a local muffler shop cut the small can off my Enthuza and replace it with this one. The Enthuza exhaust is a great piece, well made, but my car was loud enough that I'd set off alarms while slowly driving through the parking garage at my office. I even added added a resonator and it still wasn't quiet enough. The big manglaflow is amazing, now the car is basically 100% stealth.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
akbloom is offline   Reply With Quote
Old 11-18-2016, 12:00 PM   #58
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 12,847
Total Cats: 871
Default

Quote:
Originally Posted by akbloom View Post
The big magnaflow is Great. I ordered mine on Amazon and had a local muffler shop cut the small can off my Enthuza and replace it with this one. The Enthuza exhaust is a great piece, well made, but my car was loud enough that I'd set off alarms while slowly driving through the parking garage at my office. I even added added a resonator and it still wasn't quiet enough. The big manglaflow is amazing, now the car is basically 100% stealth.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
You can get the same muffler on Advance Auto's website, use trt41 and get $40 off the order.
shuiend is offline   Reply With Quote
Old 11-18-2016, 12:08 PM   #59
Senior Member
iTrader: (1)
 
Join Date: Aug 2016
Location: Woostuh, MA
Posts: 1,479
Total Cats: 39
Default

Quote:
Originally Posted by shuiend View Post
You can get the same muffler on Advance Auto's website, use trt41 and get $40 off the order.
OHHHHH!!!

Hmmmm.
ridethecliche is offline   Reply With Quote
Old 11-18-2016, 12:11 PM   #60
Destroyer of Inconel
iTrader: (37)
 
EO2K's Avatar
 
Join Date: Apr 2010
Location: In ur driveway, abusin' ur WPA
Posts: 9,132
Total Cats: 836
Default

Quote:
Originally Posted by shuiend View Post
You can get the same muffler on Advance Auto's website, use trt41 and get $40 off the order.
Does that work for stuff other than mufflers? Might be time to order a spare O2 sensor.

I love me some quiet exhaust and I should point out I'm running the Magnaflow 1x579 AND a Vibrant 17950 great big sonnovabitch 3" resonator. I posit that I have the quietest, stealthiest, free flowingist exhaust <clarkson> ...in the world. </clarkson> The fact that I'm running that resonator is a testament to gesso's ability as a fabricator.
EO2K is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Flow force injectors Claybay09 WTB 2 03-27-2016 07:17 PM
help getting started gtred MEGAsquirt 10 03-25-2016 11:55 AM
My (Re?)build thread: Oh deer! Shane_NA6 Build Threads 8 03-24-2016 09:54 PM
Help me save this poor Miata borka Prefabbed Turbo Kits 36 03-17-2016 06:46 PM


Tags
efr, efr 6258, nb2, tse, turbo

Thread Tools

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 11:39 PM.