barnshaw

iTrader: (1)

if scoobyclinic themselves are recommending not do do it then just dont do it if you are unsure, or do it and just accept it might shorten the life of it.

the term "from the horses mouth" is applicable right here.

MattyB1983

iTrader: (51)

Doesn't mean every engine, box or in this case turbo can though.
Banny was running well in excess of 500bhp on standard newage engine, doesn't mean every standard newage engine will tolerate it though.
Stick a thread up asking for people to post who have blown a classic engine/box to bits at under 350bhp.

ScoobySteve69

iTrader: (13)

That sounds awful. Sounds like it`s fooked IMO.

MattyB1983

iTrader: (51)

Sounds like what's fooked ??

madscoob

iTrader: (3)

allways makes me giggle the gearbox subject.
what makes people think that a gearbox designed to take 300hp would have a service factor of more than 1.1 that means its capable of transmitting 330 for short periods,350 or above will kill it very quickly, industrial gearbox's have a service factor as close as possible to the minimum needed, what makes people think cars are any different. engineering is engineering be it automotive or industrial, the only exceptions i know of in cars is the ford mt75x box and the newage 6 speed, oh and a gearbox i replaced for a customer that was 52years old and had a service factor of 7to1 , the only reason it failed was lack of oil due to a leaking seal , it had such a high service factor (was transmitting 134nm of tourque and was capable of around 700 ) this was because back then computers' didn't work out the service factor so engineers just guessed

harvey

iTrader: (48)

Automotive gearboxes have to handle various torque loadings throughout every journey and in most applications they can only be fully loaded for brief periods of time. For the bulk of their life they live well below 50% of their actual maximum operating level. They also have to handle a variety of driving techniques to put it politely.
Industrial gearboxes tend to operate within a much smaller torque range and many are in constant speed applications. Shock loading is often engineered out.
The TY752 gearbox for MY93 to 98 will in my practical experience give up the ghost at some point when the car reaches 350 bhp or thereabouts on a 2 litre. I suspect part of the problem is that the casing is not rigid enough.
TY754 gearboxes MY99 onwards in 5 speed application are far stronger with a far more rigid casing. I have operated STi 6/STi 5/ P1 gearboxes well beyond 500 bhp. Numerous people operate these gearboxes beyond 400 bhp. The only problem I have had on cars I have owned, fitted with TY754 gearboxes has been with the centre diff. These boxes were originally designed to operate up to 280 bhp and I guess they were improved by Subaru because they realised the weaknesses inherant with the previous 752.
Now the 6 speed gearboxes have a far heavier casing so the gearshafts are held rigidlly in position and the 6 speed box has proven to be very robust with numerous examples in cars of 500 and 600 bhp. The 6 speed box has taken over from the PAR gearsets because they are more reliable and installed secondhand a far more cost effective option.
The manner in which the gearbox is treated, the maintenance and use of the correct grade of oil greatly affects reliability.

markb_s1

Have i been describing the wrong thing all this time then?

what i'm referring to is an allioy hard pipe with one take off which replaces the square plastic box connected in the intake pipe between the maf and the turbo?