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Old 09-29-2008, 10:52 PM   #26
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Quote:
Originally Posted by jhargis View Post
Haha, no that template falls far short of bling... That will be the base for the production jig. The part itself won't be much more fancy but I'll make it look at least slightly more impressive. However, the basic fitment and layout of the main reinforcement will be the same. I just posted the pic to give folks an idea of how it works.

As for sourcing the hardware... well... Trade secret. But I doubt Ace would have class 10.9 bolts in 200mm length, few places in the country do. Let's just say it took me some days and lots of phone calls to find . You won't find them on the shelf anywhere... I'm looking at 1-2 week lead times on the bolts as it is, as standard sizes usually only run up to 120mm-140mm through most suppliers.
McMaster Carr could probably hook you up. Or worse yet Fastenal, but you would have to double your price to use their hardware.

I know this is a serious issue with the Honda guys running B series transmissions due to the multi-piece cases. Mainly guys running H2B, making the massive amount of torque on boosted H's. I do believe there is a company that makes a case girdle that has similar goals of your design.

If I was planning on keeping the five clunker in my car with gears (RA or other) I would definitely find this worth every penny. However, I cannot bring myself to spend 4k on gears alone....
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Old 09-30-2008, 01:46 AM   #27
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Haha, yeah, even McMaster doesn't carry class 10.9 in the size I need... They have them in class 8.8, but that wouldn't accomplish much.

I hear you on the costs. Even I was too much of a cheap skate for PPGs and settled for an imported STi 5mt. The more I look at the layout of the case around that pinion gear and seeing xdrian's cracked case pictures, I'm really thinking the case design is causing some trouble in that area.
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Old 09-30-2008, 02:33 PM   #28
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Well, my take on the situation is - I've already lost 2 gear sets including a stock set and a cryo treated stock set... Do I really want to lose a set of the old RA gears that were still decent? Anything CAN and WILL help, right? Well - next mod for me is going to be the 10.9 hardware along with some braces from jhargis.

I basically don't want to lose another gearset and I am trying to prevent paying for PPGs at all costs. The longer I can make my **** last - the longer I can put off dropping 5 grand or more on another gearset.
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Old 09-30-2008, 03:05 PM   #29
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Got my MIG machine all up to snuff for production (dumped some green into upgrading the thing)... So now that it's back up and running, I'm thinking I will get moving on building the test fixture today and tomorrow.

I know damn well the case is going to exhibit flex (fatigue fractures don't happen without flex), but I only have an educated guess as to where it is flexing and by how much. So this will get interesting.

I'll share how much dimensional change I find (assuming I find any), but if you guys don't mind, I will be a bit guarded as to revealing where it is flexing until the reinforcement is ready for production... I don't feel the need to be going and dumping time and money into this kind of detailed R&D only for somebody else to release their own reinforcement based on my research

Though I will make all R&D info available upon release of the part... I want people to buy the part because they understand why they need it, not just because I'm telling them that they should buy it.

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Old 10-01-2008, 05:37 PM   #30
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What gearset are you planning on running after your idea is functional? How are you ever really going to know if it works? Are you going to try to break it or just drive it around town? Just a few questions..not hatin. If it works, awesome.
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Old 10-01-2008, 07:27 PM   #31
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I also love the idea of the aluminum shifter bushings! I always wanted some but no one ever made them. Ever think of making a whole shifter assembly?

Keep it up with the ingenious ideas Jan!
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Old 10-01-2008, 11:16 PM   #32
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Well, the test fixture is done... All I need to do is grab that gigantic torque wrench and a 7/8" 12 point deep socket (it actually fits the splines on the input shaft pretty snugly). I'll throw a dial gauge at a bunch of different points on the case and start sinking torque into the trans... we'll see what happens.


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Old 10-01-2008, 11:32 PM   #33
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What gearset are you planning on running after your idea is functional? How are you ever really going to know if it works? Are you going to try to break it or just drive it around town? Just a few questions..not hatin. If it works, awesome.
I'll be sticking with my non-RA STi transmission... Basically the same thing as LGT gears. I have a conservatively tuned vf-39 setup, so I'm not pushing amazing power. My case is the old weaker 4-bolt style though, so it's going to get some serious custom reinforcement work done when I drop it out to replace the old clutch soon

Look at the post above. I'll be actually applying a measured amount of torque to the transmission in that test fixture and seeing if and exactly where case distortion is occurring. Then I'll bolt the reinforcement on and measure again... That should give me a good idea of whether it's working or not.

Quote:
Originally Posted by xdrian View Post
I also love the idea of the aluminum shifter bushings! I always wanted some but no one ever made them. Ever think of making a whole shifter assembly?

Keep it up with the ingenious ideas Jan!
Yup, aluminum bushings will be the next thing in the works. I'm even thinking of using roller bearings instead of bushings if I can find something that will be adaptable... I'm also looking into a much stronger u-joint setup for the shifter link on the transmission side of the shift assembly, the stock part is crap and has bushings that cannot be replaced as the assembly is riveted together. I've got a couple of truly bad-ass ideas brewing on that one

Thanks for the encouragement!
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Old 10-02-2008, 12:16 AM   #34
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Interesting thread. Yet there are more problems are there with this wimpy case. How about the threads that strip easy for the slave for the clutch. ok then there is the snout that wears out over time. Yet with out going around the case I can't see these so called braces would be very effective. Then again what about a pump and cooler.

Aluminum bushings would be unforgiving and loud.
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Old 10-02-2008, 12:45 AM   #35
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True, it's very tough to address all of the issues that the aging design of the 5mt transmission presents... There was some company offering a steel collar and over-sized throwout bearing at one time, not sure if they're still in business. I figure adding some strength can't hurt. That's sort of the idea behind testing the case itself. This way I can zero in on specific areas that need the reinforcement most even if I can't solve all of the 5mt's design woes.

The aluminum shift bushings would be fairly low volume production meant for competitive driving. They'd definitely transfer some gear noise into the cabin. However, race cars tend to be noisy and unforgiving. I wouldn't recommend that kind of thing for somebody that doesn't want a noisy daily driver... unless you're a weirdo like me who loves gear noise.

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Old 10-02-2008, 02:01 AM   #36
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Originally Posted by jhargis View Post
True, it's very tough to address all of the issues that the aging design of the 5mt transmission presents... There was some company offering a steel collar and over-sized throwout bearing at one time, not sure if they're still in business.
I have one. They are still in business.

Quote:
Originally Posted by jhargis View Post
I figure adding some strength can't hurt. That's sort of the idea behind testing the case itself. This way I can zero in on specific areas that need the reinforcement most even if I can't solve all of the 5mt's design woes.

The aluminum bushings would be fairly low volume production meant for competitive driving. They'd definitely transfer some gear noise into the cabin. However, race cars tend to be noisy and unforgiving. I wouldn't recommend that kind of thing for somebody that doesn't want a noisy daily driver... unless you're a weirdo like me who loves gear noise.
Yes I understand but if you put those braces I would think that a U shaped brace(s) might help better. Yet I not scene blown boxes missing parts of the case unless the gear let go. Yet the price of the case is not unreasonable. It's to bad they don't make it from stronger material.

Ok aluminum mounts but I think your design won't hold very well. Cusco mounts seem like a better idea. Less vertical of a mount. Less failure problems. I would think I different method of a larger more solid. Yet this is just my thoughts.
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Old 10-02-2008, 02:50 AM   #37
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I'm mostly focusing on increasing torsional rigidity around the gears and limiting expansion on the ring & pinion side of the front diff housing. 1/4" steel plate is not the easiest stuff in the world to twist.

Again, hardware will be upgraded as well. Class 10.9 metric bolts will allow for roughly a 30% increase in yield strength over the stock bolts. So not only will the case be reinforced against torsional flex and expansion in the front diff cavity, but the case halves will be clamped together tighter.

Hybrid, Not sure what you mean by "mounts." I was planning on releasing some aluminum shift bushings down the road... But no plans on a transmission mount yet. If you're referring to anything in the picture of the test fixture, that's simply a frame to keep all output shafts from spinning while I apply torque to the input shaft.

Last edited by jhargis; 10-02-2008 at 02:57 AM.
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Old 10-02-2008, 07:38 AM   #38
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Quote:
Originally Posted by jhargis View Post
I'll be sticking with my non-RA STi transmission... Basically the same thing as LGT gears. I have a conservatively tuned vf-39 setup, so I'm not pushing amazing power. My case is the old weaker 4-bolt style though, so it's going to get some serious custom reinforcement work done when I drop it out to replace the old clutch soon

Look at the post above. I'll be actually applying a measured amount of torque to the transmission in that test fixture and seeing if and exactly where case distortion is occurring. Then I'll bolt the reinforcement on and measure again... That should give me a good idea of whether it's working or not.



Yup, aluminum bushings will be the next thing in the works. I'm even thinking of using roller bearings instead of bushings if I can find something that will be adaptable... I'm also looking into a much stronger u-joint setup for the shifter link on the transmission side of the shift assembly, the stock part is crap and has bushings that cannot be replaced as the assembly is riveted together. I've got a couple of truly bad-ass ideas brewing on that one

Thanks for the encouragement!

i want to be one of the first to get those pieces, i hate how sloppy my shifter feels even tho i have upgraded bushings
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Old 10-02-2008, 12:15 PM   #39
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ops my mistake on the mount. Yet if I am not mistaken the middle of the trans would have no reinforcement where it's shown to need it.
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Old 10-02-2008, 01:03 PM   #40
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Well a few things that I note in the initial design:

A flat plate on the side isn't going to prevent flex or twist. The bosses it's bolted to will just snap off (they snap from simple road debris impact sometimes).

You will need get the plate bolted at the 5mt's strongest points, the bell housing bolts and the transfer case attachment points to make it effectively stop the flex and twist in the main case.

The front tube piece has no vertical reinforcement so it will twist with the case and probably break the case at the front diff where it is bolted to.

I think if you can combine your two pieces then we'll be headed down the right road.

If you are going to try and test the designs you will need to apply about 600 ft/lbs of shock load to the input shaft while keeping the front diff and rear output shaft stopped.

A slowly applied torque load will not be able to create the kind of load see even under normal driving and that's alot less than a launch.

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Old 10-02-2008, 03:27 PM   #41
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Thanks for the input.

Yeah, the 2 braces would definitely compliment each other best, as there would be some direct load transfer occuring between the main reinforcement and the bellhousing via the diff brace. And in fact I am looking at the feasability a tubular structure to link the reinforcement plate itself to the bellhousing... just figuring out how much that will cost.

As for the main reinforcement attachment points, take a closer look, they are not being bolted to bosses on the outside of the case... The bolts that hold the plate on are actually the long 8mm and 10mm bolts that run through the bearing cradles and clamp the case halves together... There will be some short spacers welded on to the transmission side of the plate to lift the plate just above the webbing on the side of the case.

As for the brace, the diff housing up front should be pushing on the middle attachment point rather than pulling... I'm basing this on the pictures I got of xdrain's case.

Trust me, I'm a major pessimist, an engineer's worst nightmare toward myself... I always try my best to find potential failure points in my designs so I can revise and improve the usefulness of the part. I wouldn't be sinking this kind of effort into checking dimensional change in the case for no reason.

Dylan, wait until you see a pic of the $1200 torque wrench I'm borrowing from work for this one... It's a monster, and can be set north of 650ft./lbs. of continuous torque application. This thing does not play around, I'm actually sincerely a little bit worried that I will break my transmission with it. Don't worry, the case is going to be seriously put through it's paces with this thing

The dial gauge that I will take measurements with will be anchored to one of the bellhousing bolt holes on an extended "arm" of sorts, so all measurements will be relative to the bellhousing... Should be a good place from which to measure expansion on the sides of the case and any dimensional change that results from torsional force (twisting of the case)

Last edited by jhargis; 10-02-2008 at 11:49 PM.
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Old 10-02-2008, 03:58 PM   #42
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The wrench on the right is an average size 200ft/lb model (what you'd normally see in the average shop)... The monster on the left is a 700ft/lb model that I will be using to sink torque into the gearbox. Now THAT is a torque wrench!


Last edited by jhargis; 10-02-2008 at 04:10 PM.
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Old 10-02-2008, 09:21 PM   #43
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Here's the test rig in its entirety. I did some testing, but before I go into detail, I'll list some limitations of the test fixture.

-It is not bolted to an engine block, and I'd guess that the engine provides some support to the case
-This jig simulates 100% traction with an infinitely heavy car (it holds all output shafts completely rigid).

Now with that out of the way... HOLY CRAP, the "theory" of case flex is now a law. This thing isn't just kind of weak, I was really surprised by my findings. I'll have a full write up with the release of the reinforcements as I don't want to make a blue print of exactly how somebody else should build a competing reinforcement right away.

I measured changes of dimension at 7 different spots on the case. One data set was recorded at 230ft/lbs, and a second data set at 300ft/lbs. At stock torque (230ft. lbs continuous load) with 3rd gear engaged, I measured a peak dimensional change of .003" at one spot of the case in relation to the bellhousing. That doesn't sound like much, but the 5mt's gear lash spec is .006" with a tolerance of +/-.001". What this means is that the gears are potentially moving beyond their recommended clearance range even at stock power, they're most certainly wildly beyond the recommended tolerance during a launch or hard shift. I stopped at 300 ft/lbs... The input shaft was twisting so much that I feared for my spare transmission's safety. Remember that this data was recorded with the output shafts completely bound up.

Another interesting tidbit that confirms input shaft flex... At 230 ft/lbs, the shaft twists at least 5 degrees at the clutch in relation to 3rd gear... In other words, with the gear locked in place, the clutch disc is about 5 degrees of rotation ahead of the gear... Think of the swirl pattern on a candy cane. At 300 ft/lbs of input torque the input shaft had moved to about 10 degrees of twist... scary.

Furthermore, I understand that my test results may be hard to take seriously since I have a clear incentive to make the case sound weak (being that I want to build a product to reduce flex), so I will have video of the test up on my website once the reinforcements are ready for production... This way all of you folks can watch the needle on my dial gauge go nuts every time I lean on that torque wrench


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Old 10-02-2008, 11:11 PM   #44
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interesting thoughts from DS1
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Old 10-03-2008, 12:48 AM   #45
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interesting thoughts from DS1
Indeed, and based on my measurements, Dylan is, as usual, dead on. The design is being revised somewhat to tie into the bell housing bolts on the passenger side of the trans. Though I think he was not clear on how it attaches to the case in his last post... The plate itself will remain basically unchanged and will reamain secured to the case using the case bolts themselves. The diff brace on the driver's side won't really need to be improved upon... That design is pretty much right where it needs to be

I have however dropped any hope in a center diff housing reinforcement... didn't really get much good measurable expansion back there, so I will focus mostly on the forward areas of the gear case where expansion seems most prevalent.

I'm planning to leave the trans in the test fixture though... as soon as my hardware comes in, I'll revise the reinforcement plate once more and test again with reinforcements installed to see if dimensional changes decrease.

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Old 10-04-2008, 10:54 AM   #46
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Originally Posted by jhargis View Post
At stock torque (230ft. lbs continuous load) with 3rd gear engaged, I measured a peak dimensional change of .003" at one spot of the case in relation to the bellhousing. That doesn't sound like much, but the 5mt's gear lash spec is .006" with a tolerance of +/-.001". What this means is that the gears are potentially moving beyond their recommended clearance range even at stock power,
I'm glad you said "potentially", otherwise your conclusion would not be logically sound.

To eliminate uncertainty you would first have to determine how much the measured deflection actually translates into additional clearance, since the two are almost certainly not directly proportional. Assuming it does, you would then have to establish that Subaru did not take that additional clearance into account when specifying the gear lash.

From a purely academic standpoint your results are interesting. I wonder what this looks like for the 6MT, which is considered by many to be bulletproof. You wouldn't happen to have one of those lying around?
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Old 10-04-2008, 11:40 AM   #47
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i would try and beef up that fixture. i think a lot of the measured flex might be in the fixture itself. get some good 4x4 1/4 wall tubing with some larger mounts. i dont think galvanized yard tubing mig welded together would be strong enough.

m2c

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Old 10-04-2008, 04:10 PM   #48
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I'm glad you said "potentially", otherwise your conclusion would not be logically sound.

To eliminate uncertainty you would first have to determine how much the measured deflection actually translates into additional clearance, since the two are almost certainly not directly proportional. Assuming it does, you would then have to establish that Subaru did not take that additional clearance into account when specifying the gear lash.

From a purely academic standpoint your results are interesting. I wonder what this looks like for the 6MT, which is considered by many to be bulletproof. You wouldn't happen to have one of those lying around?
Exactly... It also depends on where I measured. The spot at which I measured the largest amount of dimensional change is probably a pretty good indicator of lash between the ring and pinion gears though. Most manufacturers spec anywhere between +/- .001" and +/- .003" for their tolerance on gear lash and R&P clearance regardless of case design... Perhaps this is why Subaru's spec is a narrow range (only 1 thousandth in either direction), they might have been expecting a particular amount of flex and set the tolerance in a more narrow range to make up for tolerance stacking between the case and gears.

Hey if anybody has a 6mt they would like to donate, I'm all for it... Though I doubt I'll get too many offers

Quote:
Originally Posted by tom@heartboy View Post
i would try and beef up that fixture. i think a lot of the measured flex might be in the fixture itself. get some good 4x4 1/4 wall tubing with some larger mounts. i dont think galvanized yard tubing mig welded together would be strong enough.

m2c

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I'm glad you brought that up... Actually the fixture flexed less than I expected, though it did have some give. I was waiting for a sharp guy to come along and point this out I'll explain how I got around this problem.

Here's the foundational concept behind my measurement technique: ALL measurements were taken in relation to bolt locations on the bell housing of the case. The dial gauge and it's mount point were not in any way contacting the fixture and should not have picked up any flex in the fixture. If I wanted to take measurements relative to a fixed point off of the case, then the fixture would have had to be exceptionally stiff.

The disadvantage of course is that any flex in the bellhousing could also translate into additional movement of the dial gauge. Though my main point was to find peak areas of flex in the case and basically to prove that a measurable and significant amount of flex actually does in fact occur in the Subaru 5mt case rather than focusing on measurements taken against a fixed reference point away from the case.

The whole test fixture project is more a proof of concept and way to find the weakest points so I know where to apply reinforcement. I could build a very nice fixture for $400-500 and LOTS of labor time that would give me acceptably accurate measurement in relation to a fixed point, and that would give me essentially the same findings, but with a level of accuracy beyond what I need.

<-- Also professional experience testing products to destruction and 4 years in a metrological bachelor's degree program (Metrology, the science of measurement, not to be mistaken with metallurgy or meteorology).

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Old 10-04-2008, 06:55 PM   #49
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http://www.youtube.com/watch?v=Lq3cnCp7jj8&feature=user


around 2:36 you can see where all the wheel hop caused the crack in my case.
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Old 10-04-2008, 08:32 PM   #50
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Update: I was thinking of adding something to tie into the bell housing as Dylan suggested, though I don't think I can fit anything there without interfering with the axle or down-pipe.

Not a huge deal really though. I'll go ahead and test the reinforcement as-is when the stronger bolts finally come in to see if it helps. My measurements along the top of the case didn't show much movement, whereas the bottom kind of twisted out toward the passenger side of the car by a couple of thousandths of an inch (torsional distortion). The nice thing is that most of the twist was registered behind the front diff where the case starts to narrow down into the compartment that holds gears 1 through 5... but we'll see how it goes.

On a bright note, I modified the test fixture to clear the diff brace and made another front diff brace for testing. I found the dial gauge only barely registering .001" of expansion just above the driver's side axle stub with it installed where I was seeing a hair over .003" of expansion without... So I'm happy to say that the diff brace definitely is making a difference
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