Installed Exact Motorsports front camber spacers, but got question now about height?
05-29-09, 07:19 AM
#31
Thats a good find, did it specify whether the bolt was lubricated or dry?
Here were my findings for proper preload of a M12 12.9 bolt.
T = K*U*D*P
K is a constant of 1.33
U is .2 for an unlubricated bolt
D is diameter, in this case 12mm or .012m
P is pressure
To calculate P I took the yield stress of a 12.9 bolt (1100Mpa) by the area of the minor of the bolt (.000092m^2) for a total of 100770N. As we want to preliad the bolt I used 67% of the total for preloading as that is generally a standard number for these applications.
Plugging that back into the previos equation gives you a preliad torque of 215 N*m or 158.952 ft * lbs for an unlubricated bolt.
If you change the coefficient of friction (U) to .09 for a lubricated bolt you get a torque of 71.5277 lbs.
Here were my findings for proper preload of a M12 12.9 bolt.
T = K*U*D*P
K is a constant of 1.33
U is .2 for an unlubricated bolt
D is diameter, in this case 12mm or .012m
P is pressure
To calculate P I took the yield stress of a 12.9 bolt (1100Mpa) by the area of the minor of the bolt (.000092m^2) for a total of 100770N. As we want to preliad the bolt I used 67% of the total for preloading as that is generally a standard number for these applications.
Plugging that back into the previos equation gives you a preliad torque of 215 N*m or 158.952 ft * lbs for an unlubricated bolt.
If you change the coefficient of friction (U) to .09 for a lubricated bolt you get a torque of 71.5277 lbs.
Last edited by macd7919; 05-29-09 at 08:26 AM.
05-29-09, 08:12 AM
#32
those are exactly what i got! yeah, they do specify they only + or - 1 more degree of adjustment. basically that offset metal circulate disc is bigger than the oem one it replaces. thus bigger circle meaning pushing or pulling in the hub assembly (or whatever u call it) in or out more. so technically, if i was going VIP, i can use the camber kit to push it out to more neg camber. i think my readings before the kit were -2.3 degree, so i could have pushed it out around -3.5 according to what spc says. i noticed that the rears dont nearly have as much negative camber as the front do after you drop the car, and so i was looking for something mild to bring the camber back within spec.
if you want something greater, to give you more negative camber, then one of those aftermarket rear camber kits like the sage or exact motorsports rear kit is the choice. i would have gone that route if i didnt see the spc camber kit months prior to exact coming out with theirs. I use to work for an aftermarket car shop, so getting in ingalls, spc, eibach kits was pretty norm. the spc rep was the one that emailed me saying they came out with a kit for the GS.
exact hasnt given an answer probably because its an isolated incident. there has only been reports of 1 failure. everything else is speculative. 1 failure out of how many bolts that were made is pretty good numbers. and they responded to that customer pretty swiftly too. if anything, they didnt manufactuer the bolts, they simply bought them off a manufactuer. they could have very well cheaped out and got some low grade bolts, but they sourced out and got the highest grade bolts possible. i donno about you but thats pretty good in my books, even if all they needed was a bolt that could handle to oem spec. Ppl are just jumping on it as if it was firestone tires on ford explorers. the bolt could have simply been a bad one that no one can see, micro fracture, some issue that no one can see from manufactuering, tempering the metal to harden it, maybe it was that 1 bolt that just sucked. either way they have delt with it swiftly as much as they can.
honestly, they are a parts supplier, asking them questions related to manufactuering and specs beyond what they know is no different than asking engine specs to the stock boy at walmart in the automotive division. thats why i didnt bother jumping in on that thread, no need, im not gonna get an answer from them. and most likely there are far more informative guys here on clublexus.
im just happy everything i got so far has at least worked in some way positive! hahaha
Next performance mod that im looking at is turbo supra front brakes, and turbo supra 3.76 lsd.
Next non performance mod that im looking at is a squash scented air freshener that will last more than 4 months. ohh and my puddle lights!
if you want something greater, to give you more negative camber, then one of those aftermarket rear camber kits like the sage or exact motorsports rear kit is the choice. i would have gone that route if i didnt see the spc camber kit months prior to exact coming out with theirs. I use to work for an aftermarket car shop, so getting in ingalls, spc, eibach kits was pretty norm. the spc rep was the one that emailed me saying they came out with a kit for the GS.
exact hasnt given an answer probably because its an isolated incident. there has only been reports of 1 failure. everything else is speculative. 1 failure out of how many bolts that were made is pretty good numbers. and they responded to that customer pretty swiftly too. if anything, they didnt manufactuer the bolts, they simply bought them off a manufactuer. they could have very well cheaped out and got some low grade bolts, but they sourced out and got the highest grade bolts possible. i donno about you but thats pretty good in my books, even if all they needed was a bolt that could handle to oem spec. Ppl are just jumping on it as if it was firestone tires on ford explorers. the bolt could have simply been a bad one that no one can see, micro fracture, some issue that no one can see from manufactuering, tempering the metal to harden it, maybe it was that 1 bolt that just sucked. either way they have delt with it swiftly as much as they can.
honestly, they are a parts supplier, asking them questions related to manufactuering and specs beyond what they know is no different than asking engine specs to the stock boy at walmart in the automotive division. thats why i didnt bother jumping in on that thread, no need, im not gonna get an answer from them. and most likely there are far more informative guys here on clublexus.
im just happy everything i got so far has at least worked in some way positive! hahaha
Next performance mod that im looking at is turbo supra front brakes, and turbo supra 3.76 lsd.
Next non performance mod that im looking at is a squash scented air freshener that will last more than 4 months. ohh and my puddle lights!
Last edited by SorrGwa; 05-29-09 at 08:53 AM.
05-29-09, 08:18 AM
#33
awesome find and response!
I did a quick search and found this torque spec. online. Obviously it would be better to find the "Actual" manufacturers spec. from Exact's bolt supplier, but nevertheless, this chart does show that 120ft.lbs "can" be within the spec of this bolt.
As for the one person who reported the broken bolt, without an actual failure analysis being performed on that failed bolt, there is no way we can do any more then speculate what the root cause could be. (over torque, torque wrench out of calibration, cross threaded, bolt manufacturer defect, lubricated thread, etc.)
If someone wants to ***-U-ME the root cause of the bolt failure, well you know what they say.
Note: I converted kg.m to ft.lb.
Last comment: I'm not implying that the torque specified is appropriate for the intended application, I'm merely stating that this torque spec shows it is not beyond the limits of the tensile strength for a bolt of this size.
As for the one person who reported the broken bolt, without an actual failure analysis being performed on that failed bolt, there is no way we can do any more then speculate what the root cause could be. (over torque, torque wrench out of calibration, cross threaded, bolt manufacturer defect, lubricated thread, etc.)
If someone wants to ***-U-ME the root cause of the bolt failure, well you know what they say.
Note: I converted kg.m to ft.lb.
Last comment: I'm not implying that the torque specified is appropriate for the intended application, I'm merely stating that this torque spec shows it is not beyond the limits of the tensile strength for a bolt of this size.
05-29-09, 08:28 AM
#34
here is a picture of the spc camber kit installed after a season in the salt/snow/rain. so yeah they lost their luster but work great. some ppl said they look kinda cheapish looking, but in all fairness, spc is a well known brand name, and the actual kit quality is pretty sturdy. all metal is heavy and thick, install was easy with the right tools (air rotary bit tool)
(click on the pic to see the original picture size)
(click on the pic to see the original picture size)
05-29-09, 10:49 AM
#36
Nah I just read a lot, plus being an Engineer helps a bit.
Funny that Daizen had this same design in the works and posted "coming soon" but never released it.
I'm guessing because the adjustment was limited to only 1 degree of improvement. Compare this to the Exact / Sage RCAs which can do up to 3 degrees.
Anyone with no finger gap or tucked is gonna need more than 1 degree improvement, but these look like good options if you have a moderate drop.
here is a picture of the spc camber kit installed after a season in the salt/snow/rain. so yeah they lost their luster but work great. some ppl said they look kinda cheapish looking, but in all fairness, spc is a well known brand name, and the actual kit quality is pretty sturdy. all metal is heavy and thick, install was easy with the right tools (air rotary bit tool)
(click on the pic to see the original picture size)
(click on the pic to see the original picture size)
Funny that Daizen had this same design in the works and posted "coming soon" but never released it.
I'm guessing because the adjustment was limited to only 1 degree of improvement. Compare this to the Exact / Sage RCAs which can do up to 3 degrees.
Anyone with no finger gap or tucked is gonna need more than 1 degree improvement, but these look like good options if you have a moderate drop.
Last edited by RMMGS4; 05-29-09 at 10:54 AM.
05-29-09, 12:08 PM
#37
Funny that Daizen had this same design in the works and posted "coming soon" but never released it.
I'm guessing because the adjustment was limited to only 1 degree of improvement. Compare this to the Exact / Sage RCAs which can do up to 3 degrees.
Anyone with no finger gap or tucked is gonna need more than 1 degree improvement, but these look like good options if you have a moderate drop.
I'm guessing because the adjustment was limited to only 1 degree of improvement. Compare this to the Exact / Sage RCAs which can do up to 3 degrees.
Anyone with no finger gap or tucked is gonna need more than 1 degree improvement, but these look like good options if you have a moderate drop.
https://www.clublexus.com/forums/sus...amber-kit.html
05-29-09, 01:04 PM
#38
honestly, they are a parts supplier, asking them questions related to manufacturing and specs beyond what they know is no different than asking engine specs to the stock boy at walmart in the automotive division. that’s why I didn’t bother jumping in on that thread, no need, I’m not gonna get an answer from them. and most likely there are far more informative guys here on clublexus.
I was waiting for Exact to respond to that post as well, but as you pointed out, their manufacturer / designer is the one that we need to seek a response from. On that post I read that Exact did request the customer to provide the sample of the broken bolt for analysis, but the customer never returned it.
So without providing this broken part to their Manufacturer, it’s not going to be easy for Exact to expect a formal response based only from the claims of one post on one forum. Also, even if they posted a response, I’m sure there would be follow on questions posted and Exact would not be able to field those questions as well.
If a plane crashed and you were the NTSB and were expected to determine the cause of the crash, but found that there was no wreckage available to examine, how would you be able to respond? In this case, NO ONE can do any more than speculate the cause of the bolt failure.
Unless a poster is a Metallurgical or Mechanical Engineer, etc., I'd say any opinions on the cause of failure without having the technical credentials are purely speculative and un-qualified.
Last edited by RMMGS4; 05-29-09 at 01:09 PM.
05-29-09, 01:09 PM
#39
exact hasn’t given an answer probably because it’s an isolated incident. there has only been reports of 1 failure. everything else is speculative. 1 failure out of how many bolts that were made is pretty good numbers. and they responded to that customer pretty swiftly too.
I just called Exact just now to ask how many of these RCAs had they sold and the quantity was around 30, so that means 120 bolts have been installed without any other “reported” failure. Out of these 30 there were about 10 that were installed at their shop using this torque spec. Exact did make contact with the local customers that they installed and provided a free inspection and verified the torque. I don't know any further details of what that inspection entailed.
My recommendation is if you are un-comfortable with the torque spec provided by Exact, I'd suggest reducing to at or slightly more than the OEM spec and then just add Loctite.
Adding lock washers does NO GOOD at this torque rating.
.
Last edited by RMMGS4; 05-29-09 at 01:43 PM.
05-29-09, 01:13 PM
#40
Hey Glenn, I checked out that site and at the top it says this is for lubricated bolts. For some reason it didn't show up in the pic you posted but either way....so that torque would be basically doubled for a non-lubricated bolt (around 240 ft lbs). I'm not arguing with you at all or saying this is bad information as I know you do your homework as do I 
. My posts were just meant to put it out there for everyone so they can follow the reasoning/methods behind bolt torque specs. If they check out my post at the top of the page they can follow the calculations as well.
Fwiw, I don't think you were referring to me in your post but I do have a degree in mechanical engineering. You are correct, there really isn't a way to decide the failure mode without testing the bolt and it very well could have been over torqued in that case.
What I do find interesting though is the somewhat wide range of "standard" torque values for a particular grade of bolt. For instance, the chart you posted suggests using 123 ft lbs, by using my method, (67% of yield) the amount was about 150 ft lbs, others have speculated around 100 ft lbs etc...It's interesting to see that there is such a fluctuation and the values used to calculate the specs. For instance, the coefficient of friction can range from .15 to .25 for a non-lubricated bolt, maybe the companies are choosing to go on the high side or slow side of my .2. I would aslo be interested to see if they compensate for the bolt minor diameter or are just using standard diameter. It would just be interesting to see the logic behind each different spec you know?
. My posts were just meant to put it out there for everyone so they can follow the reasoning/methods behind bolt torque specs. If they check out my post at the top of the page they can follow the calculations as well. Fwiw, I don't think you were referring to me in your post but I do have a degree in mechanical engineering. You are correct, there really isn't a way to decide the failure mode without testing the bolt and it very well could have been over torqued in that case.
What I do find interesting though is the somewhat wide range of "standard" torque values for a particular grade of bolt. For instance, the chart you posted suggests using 123 ft lbs, by using my method, (67% of yield) the amount was about 150 ft lbs, others have speculated around 100 ft lbs etc...It's interesting to see that there is such a fluctuation and the values used to calculate the specs. For instance, the coefficient of friction can range from .15 to .25 for a non-lubricated bolt, maybe the companies are choosing to go on the high side or slow side of my .2. I would aslo be interested to see if they compensate for the bolt minor diameter or are just using standard diameter. It would just be interesting to see the logic behind each different spec you know?
Last edited by macd7919; 05-29-09 at 01:19 PM.
05-29-09, 01:18 PM
#41
Hey Glenn, I checked out that site and at the top it says this is for lubricated bolts. For some reason it didn't show up in the pic you posted but either way....so that torque would be basically doubled for a non-lubricated bolt (around 240 ft lbs). I'm not arguing with you at all or saying this is bad information as I know you do your homework as do I . My posts were just meant to put it out there for everyone so they can follow the reasoning/methods behind bolt torque specs. If they check out my post at the top of the page they can follow the calculations as well.
Fwiw, I don't think you were referring to me in your post but I do have a degree in mechanical engineering. You are correct, there really isn't a way to decide the failure mode without testing the bolt and it very well could have been over torqued in that case.
. My posts were just meant to put it out there for everyone so they can follow the reasoning/methods behind bolt torque specs. If they check out my post at the top of the page they can follow the calculations as well. Fwiw, I don't think you were referring to me in your post but I do have a degree in mechanical engineering. You are correct, there really isn't a way to decide the failure mode without testing the bolt and it very well could have been over torqued in that case.
I'm TOTALLY with you Damian (sp). We're both analytical and Formerly Educated about this topic and I'm just providing information and trying to put things in perspective for the non-tech people as well.
I'm not defending Exact per se on their spec. I'm sure it was recommended to them and it seems they have no re-course to get further closure on this.
In my last post #39, I made my suggestion on reducing the torque.
Edit: I didn't know you were an ME before I stated the "Engineering Credentials" on my previous post, but yes present company excepted.
Good Stuff.
Last edited by RMMGS4; 05-29-09 at 01:23 PM.
05-29-09, 01:41 PM
#43
I looked up the cost on a 12.9 grade bolt of this length of 140mm and they are $11 each.
If anyone has any liability in suggesting inferior parts on such a "critical" suspension component as this, I'm hoping that person is reading this post.
05-29-09, 01:52 PM
#44
Well now that we're on a roll, I believe there is a poster on a different thread who talked of a DIY for these RCAs and went as far as stating he could get the bolts at Home Depot (I think) for "pennies".
I looked up the cost on a 12.9 grade bolt of this length of 140mm and they are $11 each.
If anyone has any liability in suggesting inferior parts on such a "critical" suspension component as this, I'm hoping that person is reading this post.
I looked up the cost on a 12.9 grade bolt of this length of 140mm and they are $11 each.
If anyone has any liability in suggesting inferior parts on such a "critical" suspension component as this, I'm hoping that person is reading this post.
Last edited by macd7919; 05-29-09 at 01:55 PM.
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