Topic: Moore Performance Blast Plates

[monsterface]

Hey WSC,

So I was cruising Nabisco last night and stumbled across this thread for the "Moore Performance Blast Plates" http://forums.nasioc.com/forums/showthread.php?t=2658822
In a nutshell, theses blast plates are bolted on to your 5 speed transmission to stiffen the case and ultimately preserve the life your 5MT at higher than stock power levels.
Has anyone on this board seen or tried out these blast plates? Are these plates just snake oil? or is this a serious option/alternative for high power 5MT guys?

Would you throw down the $300-400 for theses plates, or would you put that money towards a STI 6 speed?
Really interested in getting peoples opinions on the product, please chime in!

EDIT: Found another thread, OP looks to be the original guy that came up with the idea, some good discussion in the thread ass-well.
http://forums.nasioc.com/forums/showthread.php?t=1602159

[Ambystom01]

I'd put the money towards an STI transmission or new gears for the 5-speed.

[LilDrunkenSmurf]

Yeah isn't it usually the gears that let go, not the case?

[monsterface]

Yes I'm pretty sure its the gears that fail. But if I've interpreted what they are saying correctly, the gears failing is a result of case flex and misalignment of the shafts when gears are being engaged. See below threads/links:

In this thread, Post #8 http://www.iwsti.com/forums/vendor-group-buys/239044-moore-performance-5mt-trans-bracing-blast-plates.html,

The plates are bolted through existing bolt locations that hold the two halves of the transmission together. By bolting these plates onto the outside around the gear set it increases the stiffness of the casing to improve gear mesh tolerances under shock loading and high torque situations.

Essentially, the load or tq will be applied to more of the gear surface, optimizing the gear's ability to hold power.

This guy explains it a little better, Post #1001 http://legacygt.com/forums/showthread.php/lalgt-rebuild-thread-152682.html?p=4365861

Tying the case bolts together in a single plane keeps the case from twisting/flexing, which With grade 10.9 bolts, and a higher torque spec, it keeps the radial thrust of the gears caused by the pressure angles of the gear causing the case to flex and misalignment of the shafts. When the shafts are not at the prescribed center to center distance the line of action can change and move the forces through the gear like it was never designed for, therefore over stressing the weakest part of the gear tooth and as a result often failure results.

[Canuckrz]

Yeah isn't it usually the gears that let go, not the case?

The explanation I've seen from looking into it is the case causes the gears to go. Because of the split case design when a lot of power is put through the 5mt the case flexes and the gears move away from each other putting them out of tolerance, same idea if you have too much backlash on a ring and pinion. The gears then chew themselves because of the slop between them.

If I had known about the blast plates sooner I likely would have put them on while my transmission was out, but no time now.

[F1Eng]

makes sense from an engineering perspective, as the centerline of the gears increase, it will increase the moment arm of the contact point on the gear and thus increase the bending stress on the gear. does the company have testing results to back up their product?

[Canuckrz]

In a couple of the group buy's they had on the other Subaru forums they were suppose to test a stock and a built 5mt to failure with the plates on it. I wasn't able to find their results however, only that they said they were going to do it.

The plates look pretty damn simple to fab up yourself, however finding that long high tensile strength hardware would likely be impossible, hence the price of the kit as they likely get their hardware custom ordered.

[F1Eng]

idk, looks like they are just using grade 10.9 threaded rod and some nylocks. I'm 99% sure you could all the parts to make those from McMaster Carr. Love that website 

edit: you could be using precision ground rod with holes tapped for studs, if those holes in the trans need to seal...

[Roadwarrior]

I thought about these but just had a hard time justifying 300-400 for a couple steel plates. If I got them id probably see if I could use them to make some of my own.

[Mitnek]

Looks like it may be legit: http://forums.nasioc.com/forums//showthread.php?t=2666430

[F1Eng]

Looks like it may be legit: http://forums.nasioc.com/forums//showthread.php?t=2666430

Pretty awesome, they should be worth the $400 for anyone looking for up to 450whp...

Thanks for the link, I didn't know subie engines could make over 500

[funk32]

Doing pulls on a dyno don't show how well or not so well these things work.. Banging through gears is the true test, like track conditions.

[Mitnek]

Pretty awesome, they should be worth the $400 for anyone looking for up to 450whp...

Thanks for the link, I didn't know subie engines could make over 500

Well I'm not sure we can still call it a subie engine at this point There's quite a few pennies in that build.

[F1Eng]

Well I'm not sure we can still call it a subie engine at this point There's quite a few pennies in that build.

touche lol

[Canuckrz]

I thought about these but just had a hard time justifying 300-400 for a couple steel plates. If I got them id probably see if I could use them to make some of my own.

Can't entirely argue, they seem like they were initially more priced for demand than necessarily the actual cost to manufacture and standard profit margin. The quick spool valve is another example of this.

That being said they look a little more complicated to make than I first thought. They're not just reinforced flat plates, there's also spacing collars welded on the back of each plate. I'm not sure if they're staggered heights or not as I've never seen the housing of a 5mt subaru first hand, but if they are staggered heights those collars would have to be very exact, and could be different heights on each side for clearance which could mean up to 6 different lengthed collars at precise height's. As if they are not the right heights on the dot the plates could actually create flex in the casing by bolting them on, instead of preventing it. Food for thought.

[F1Eng]

Can't entirely argue, they seem like they were initially more priced for demand than necessarily the actual cost to manufacture and standard profit margin. The quick spool valve is another example of this.

That being said they look a little more complicated to make than I first thought. They're not just reinforced flat plates, there's also spacing collars welded on the back of each plate. I'm not sure if they're staggered heights or not as I've never seen the housing of a 5mt subaru first hand, but if they are staggered heights those collars would have to be very exact, and could be different heights on each side for clearance which could mean up to 6 different lengthed collars at precise height's. As if they are not the right heights on the dot the plates could actually create flex in the casing by bolting them on, instead of preventing it. Food for thought.

yeah they are definitely market priced, I could probably make these with less than $50 material and an hour on the tig. And some spray paint lol

They shouldn't need to be that accurate, within 1/16" is easily achievable and would transmit the stresses the way they need. The idea is just to get some material further away from the centerline of the trans to increase the geometric stiffness of the system. If I still had Solidworks, I'd test the rigidity of the design, but it's being borrowed by our New Zealand plant 

[Jesse.Korpan]

Ive thought about these for a long time now I think I might pull the trigger when (if) I do the rest of the work to my STi (CF driveshaft, clutch,flywheel) I'm sure it helps a bit. I have at the same time heard conflicting stores that caseflex is a myth and has no real effect on the gear's / shafts and failures are instead caused from the shafts but I'm not sure how much of that is true.