Ppg s and 2.5 s ??
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From: bexhill east sussex
No mate but friend of mine is looking at this set up Iv gone the idea of using a 6 speed but the car comes with ppg but don't want it breaking any time soon.
What ppg is it? Straight cut or helical? Synchro or dog engagement? Ratios?
Im pretty sure they don't like big torque so 2.5 would be less than ideal I guess, don't quote me on that tho
Im pretty sure they don't like big torque so 2.5 would be less than ideal I guess, don't quote me on that tho
PPG struggle with torque due to the flex in the 5 speed casing, there are the "blast plates' that are supposed to go someway towards solving this problem, but tbh with what the PPG costs I'd just go with a 6 speed and be done with it.
Although it's possible to break any gearbox if you try hard enough.
Although it's possible to break any gearbox if you try hard enough.
Please not the flex bollox again. Its the rating on the gears themselves that are the limiting factor, even ppg admited that when they derated their origional kits to about 450ftlb
PPG have various kits that are rated to various levels, so depends which it is. The higher rated kits arn't cheap thats for sure, over 20k Aus dollars iirc
PPG have various kits that are rated to various levels, so depends which it is. The higher rated kits arn't cheap thats for sure, over 20k Aus dollars iirc
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Well saw a thread on here a good few years ago where some well respected professional said it was a problem, moreso on the ty52 4 bolt gearboxes, which again is the reason the ty54 6 bolt boxes seem to fair better, with that in mind it seems to hold water if you ask me, also if it's bollocks why were the later boxes up-rated in the same area where aforementioned non- existent flex occurs. 
But yes I know the kits have different ratings and that they were also revised down a few years back.

But yes I know the kits have different ratings and that they were also revised down a few years back.
Harvey Smith also ran a 5 speed up to around the 450bhp mark but advised that a certain amount of mechanical sympathy was required.
At the end of the day if the TY52 boxes were so strong we wouldn't have the TY54 or the 6 speed, if you know your Subaru history then you should know that the only reason the 6 speed exists is because of the inherent flaws in the 5 speed and it's propensity for ****ting itself in rallying.
At the end of the day if the TY52 boxes were so strong we wouldn't have the TY54 or the 6 speed, if you know your Subaru history then you should know that the only reason the 6 speed exists is because of the inherent flaws in the 5 speed and it's propensity for ****ting itself in rallying.
Harvey Smith also ran a 5 speed up to around the 450bhp mark but advised that a certain amount of mechanical sympathy was required.
At the end of the day if the TY52 boxes were so strong we wouldn't have the TY54 or the 6 speed, if you know your Subaru history then you should know that the only reason the 6 speed exists is because of the inherent flaws in the 5 speed and it's propensity for ****ting itself in rallying.
At the end of the day if the TY52 boxes were so strong we wouldn't have the TY54 or the 6 speed, if you know your Subaru history then you should know that the only reason the 6 speed exists is because of the inherent flaws in the 5 speed and it's propensity for ****ting itself in rallying.
I have a forged 2.5 and a 5 speed ppg dog box going in mine over winter and plan to run 500/500 and will be used in anger my reason for the ppg is I hate 6 speeds and failures are getting more common
will the dog box hold out only time will tell but it has come from a well know car that run more power than I'm aiming for and was used in anger every time
will the dog box hold out only time will tell but it has come from a well know car that run more power than I'm aiming for and was used in anger every time



the 6 speed was over engineered because the 5 speeds cr4ped themselves all the time.