max power for a sti 6 speed gearbox?
#1
max power for a sti 6 speed gearbox?
As the title says, I was mapping mine last night, got to 1.1 bar with a 2.5 with a .70 commpressor ,.63 exhaust housing. An hour in to mapping and the box was very noisy on lift off (layer shaft bearing??? any idea) ok when it is on power. Is it worth rebuilding the 6 speed? Or is a dog box the only option? hoping to run it at 1.6 bar max (for play time) and 1.2 for every day thanks for any help John...
#2
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I Beleve the guys in the u.s are running the six speed well over the 500/500 mark not sure how long they last at that. Only real issue i hear is oil temps. That's why a few are using oil coolers for the box but this is for extreme power. . what sort of power are you running ?
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It should be OK for your playtime if you are careful with the changes - the selector fork bushes on some examples can be easy to wear.
Mine was rebuilt after 23000 miles with est 395 to 450 lbft on a 2.5 (up to 1.7bar on GT30R, 0.82AR, headgaskets didn't like that though).
Mine was rebuilt after 23000 miles with est 395 to 450 lbft on a 2.5 (up to 1.7bar on GT30R, 0.82AR, headgaskets didn't like that though).
#4
Originally Posted by scooby-woo
what sort of power are you running ?
Does it sound like the layer shaft bearing to you guys? like an electric milk float on lift off? if so will it last on reduced power say 0.9bar? till i can afford a dog box
thanks for your quick responses
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David Wallis' 6 speed stood upto some serious abuse, with in excess of 550bhp and 490lbft. It now suffers from a slightly dodgy synchro on fast changes from 2nd to 3rd, but thats it.
My own 6 speed stood up very well to the abuse i put it through with an EJ257 and GT30R-LP at 1.6bar, and is still running well on an ej257 producing roughly 400bhp and 400lbft.
My own 6 speed stood up very well to the abuse i put it through with an EJ257 and GT30R-LP at 1.6bar, and is still running well on an ej257 producing roughly 400bhp and 400lbft.
#7
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Location: Leeds - It was 562.4bhp@28psi on Optimax, How much closer to 600 with race fuel and a bigger turbo?
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as steven says, Its had around 600+ bhp through it (hard to tell since last RR session..) they aint going to appreciate the abuse.. apparently the syncro's dont like thick oil.
David
David
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#8
In the 80's Porsche added spray bars and an oil pump to force lub the gears/bearings 'stratigically'. Same small mechanical pump fed a simple copper tube oil cooler strapped to the side of the box.
This allowed a significant increase in torque rating over previous designs.
Does the latest 6 speeder have these tweeks or similar?
Maybe I am wrong, but a synchro 'dog' (straight/semi helical) gearbox is as strong as a true Dog change box, just slower to change gear as you need to use/dip the clutch.(?)
Graham.
This allowed a significant increase in torque rating over previous designs.
Does the latest 6 speeder have these tweeks or similar?
Maybe I am wrong, but a synchro 'dog' (straight/semi helical) gearbox is as strong as a true Dog change box, just slower to change gear as you need to use/dip the clutch.(?)
Graham.
#10
#12
Originally Posted by john banks
Mine was rebuilt after 23000 miles with est 395 to 450 lbft on a 2.5 (up to 1.7bar on GT30R, 0.82AR, headgaskets didn't like that though).
#13
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I paid £1100 for a rebuild including replacing all the selector forks, synchros and bearings that could possibly need changing and were available. I could have done it cheaper, but I don't like removing 6 speed boxes!
#14
but I don't like removing 6 speed boxes!
#16
some mad project car
#19
Wasn't that bad for my dad and I to do...mind you we had speant an hour beforehand making a cradle for the gearbox that rested very nicely on three trolley jacks so we could position it easily and slide it into the engine bay...worked a treat
#20
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Me and steven never seem to struggle, unless we are hungover..
But then a 2 post lift does make it easy..
David
But then a 2 post lift does make it easy..
David
#21
I've just seen a house for sale in my price range, near where my new job is, with large garage and a pit...granted it's no 2 post lift, but it beats lying under the car at least
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