Anyone *consistently* broken standard gearboxes?

stupink · November 18, 2012, 16:50

Essentially I'm trying to suss out if i replace the gearbox now, before it breaks, and/or just leave it and if it breaks replace with another standard or consider upgrade.

So has anyone had an engine strong enough that you simply munched gearboxes in a few months? so i dont mean it broke once and that may have been caused by the extra power or it could have been going anyway.

mines a 2001 uk, low miles if i recall its about 38k.

so what torque/hp was your engine running if you did have problems, and what happened? stripped teeth? failed casing, bearings.. etc.. s:)

s:)

I'm aware pub figures of 240lbft as a "max safe", but I'd like to hear actual experiences s:)

s:)

dj2k21 · November 18, 2012, 16:58

I will let you know within the next month. I'm going to kill my gearbox off just to see what it will take

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stupink · November 18, 2012, 17:01

Be keen to hear your feedback, when it breaks and you're not expecting it, its easy to get paranoid, but if you try to break something, you get a better idea of how strong it is s:D

s:D

dj2k21 · November 18, 2012, 17:06

Yeah I'm planning on maxing the turbo as I've not been able to yet for the exact gearbox reason but with the mk2 box going in I'm not bothered about ruining it

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stupink · November 18, 2012, 17:11

mk2 turbo is what i'll be looking at also. but its a now or later thing. just aware its quite a big change, dont mind fabbing the mounts and linkages and conversion plate for bellhousing, but im a little grey on what the shaft solution is, and i can't really be affording a new clutch and flywheel etc right now on top of the box, i'd rather get it slowly over time piece by piece.

loadswine · November 18, 2012, 17:12

I think Jason ( muffdan) had a bit of an appetite for boxes until he upgraded to something stronger on his , now deceased, old car. The dyno printout I last saw for it had a big lump of torque churned out in the mid range, peaking at about 280 lbft. It is possible that he was running even more than that, as it was often being tweaked. The onset of torque on that curve was almost vertical. It was either second or third in his boxes that appeared to have chocolate qualities, if I remember anywhere near right.

dj2k21 · November 18, 2012, 17:35

Just buy the full conversion from mwr. Works out about £2k plus a mk2 box but much easier than measuring dimensions for custom shafts and things

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stupink · November 18, 2012, 17:50

I saw the conversion kit, but think its a lot of money for what it is. im happy to just fabricate bits, and you still need the clutch/fly on top of the kit iirc.. I dont mean expensive for what it is as in out priced, i just think 2k for a gearbox conversion is too much, i can buy a lot of oem boxes for that s:)

s:)

Cheers mr wine, i will have a look at his profile if i can find it, i only want to get the car a similar performance as my last, then im happy, that was 400hp but quite heavy, so im thinking 300hp should be okay in the 2, meaning i need about 250lbft, but i also want it drivable, so will be making the torque flat an linear so it emulates a N/A vehicle.. hopefully that will help a lot.. s:)

s:)

loadswine · November 18, 2012, 17:55

Yep, I think that's a good approach. A nice linear power curve and a flat torque curve without lumps or spikes will help massively.
Can't wait to see how it turns out. good luck with it. s;)

s;)

Anonymous · November 18, 2012, 18:06

With that sort of torque curve and power the gearbox might be able to take that.

dj2k21 · November 18, 2012, 18:18

The best tuned turbo cars feel n.a. that's what my tuner says anyways. I think we should have a turbo 2 meet one time

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onion86 · November 18, 2012, 20:38

Wait for me to get mine back s:)

s:)

dj2k21 · November 18, 2012, 20:40

Good luck with it mate. Hope it makes you giggle like mine does to me s:)

s:)

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ChrisGB · November 21, 2012, 17:02

What engine build are you running? 250lb/ft may be pushing stock con rods to or beyond their limit. As for the box, you could try the Jubu Racing replacement 3rd / 4th gear sets for the C6X series boxes.

I know of failure of input bearings with people running stock engines as well as turbos, but the gear failures tend to be 3rd and 4th stripping. Always a good idea to treat the box well by letting it warm up thoroughly before giving it serious stick too.

Chris