Stock 5 speed transmission
 

What are the limits on the 5spd uk2000 box in terms of bhp out of interest and what transmission oil would people recommend for the longevity of the box.

Also I watched a subaru on tv last night break high 7s on a quarter mile called the white bullet.a new world record apprently. And another subaru breaking mid 8s on a std 6 speed transmission no mods to the box :D

i had an old 5 speed running 280. was recommended not much more to be on the safe side. I think its more the torque that kills them

i think its torque and hard launches that will destroy a 5 speed. i had a version 6 sti 5 speed in my blobeye wrx making 354bhp and 365ftlbs of torque, i had it for maybe 2 years then upgraded to a 6 speed and sold the box to a mate who used it for a few years with no issues

are the ratios different in the 5spd sti compared to the uk2000

made a really really fast car is what it did, the ratios were quite short and as the box had been refreshed by api it was rifle bolt precise

i couldnt tell you mate to be fair, it was alot closer ratio than the box that was originally in the car

I'm not that bothered about long gearing I wouldn't mind knowing what these can take . Has anyone ever taken one to it's limits

I didn't no these could take 400 :Suspiciou

Eh?

didn't no stock 5spds were capable

"Destroyed 4 over probably 15,000 miles @400 bhp and similar torque"

Does this suggest that they are capable at 400bhp? I guess if you never plan on driving more more than 3000 miles, then yes, they are capable :lol1:

:lol1:

couldn't the torque be pulled back abit through mapping to save the box.the price of a 6 spd box is ridiculous

As you say, you can drive around the gearbox limitations but then it makes it rather pointless having a 400/400 engine if you are never able to use all the power.

mine will never see over 300bhp that's plenty for day to day driving. What transmission oil was you using was it anything special?

Sure. But then it's not going to be 400/400. 5 speed boxes are cheap, so if you are able to do the work yourself, you could probably drop in 4 5speeds for the price of a 6-speed conversion. If you are only doing track days then you may consider changing the box once a year as good value. However, the box could let go at any time. The first time you give it full throttle for example. Or it may last a few thousand miles of abuse.

If you have to pay someone else though, the labour costs will soon rack up. If you want 400/400, especially in a road car/daily driver and don't have the means to swap the box yourself, then 6speed is really the only sensible financial option.



Presumably you currently have a UK2000 or similar. Add up the cost of a reliable 400/400 engine plus 6-speed conversion and you may as well just save all that money towards getting an STi with 6-speed. Whilst it can seem attractive to get a cheaper WRX/5speed car and mod it over time, if you want more power than OEM bolts on’s (turbos, injectors etc) can provide; 330/350, then it makes far greater financial sense to buy an STi as a starting point. Law of diminishing returns – power is cheap and easy at first but gets progressively more expensive £/bhp. Especially once you’ve exceeded OEM parts capability and need to buy aftermarket turbos, forge the engine, strengthen drivetrain etc.



What mods/power are you running at the moment?

Why the talk of the price of 6-speed boxes then?

because I wanted to no the limitations of a 5spd box

I'm running about 220ish maybe a bit less. I rescued the car long story and doing it up in stages.just a k&n filter and front mount intercooler set up. I've put in a 255 walbro pump and new plugs and leads. I work for a main dealer as a tech

300/300 shouldn't be an issue but you can destroy a box on stock power if you abuse it. A little mechanica sympathy goes a long way.

that's why I was asking about the boxes. You no like someone who's been there and done type of thing. Gives me an idea of what I can do then. I surpose a good transmission oil would help abit as well

that's very true .I'm changing rear mains on Saturday and the oil separator along with a stock sti clutch.

For time attack racing (so no hard launches) do you think a GC8 5 speed STI box would still suffice or again is the best option the 6 speed box.... Trying to sort out my budget for the next year. I'll be running close to 400.

Cheers,

ouch I'm already running ~330. WIll have to put the new turbo back until after the 6 speed.

thanks for the info