osborne

I keep seeing people selling sti blocks etc, is there an advantage to having the sti block compared to the wrx?
can they take more power before they go pop?
etc



And if i got a 2.5 block from a newage second hand would i be puchin my luck as i've been looking an they seem rather cheap.

If i did this how hard is this to change? Possible to do it in a garage at home with two mates that are mechanics or woulds i hit problems? then get it mapped at a tuning garage.

osborne

any answers?

Slowboy Racing

Wrx will generally be open deck and the STI semi closed but this will also depend on year etc as it’s not always the case. Using a semi closed deck will give you a stronger base over the open deck and so on.

The 2.5 uses the semi closed deck with larger bores and greater stroke to achieve the 2.5 displacement. And will ultimately be a better choice for a road car. I personally would suggest if considering a conversion like this you need to be well rehearsed to carry this out correctly and is best left to a tuner if your not.

Also bear in mind its not just the block that makes a strong motor there are plenty of open deck blocks running good power its only worth considering the block if your going for a full build. I would suggest looking at rods and pistons first.

osborne

with the full build would i need to change crankshaft or are they ok?

How much does your garage charge for this work if parts are supplied?

Slowboy Racing

Generally speaking it’s good to go for a new crank on a forged build considering the cost of a new crank and having the existing reground Amongst other things like wear etc, however the standard crank is perfectly capable in a forged motor and is used in most if not all big builds.

dazdavies

iTrader: (22)

For the earlier classics some were closed deck majority were open deck.
The later classics there was no differences in the WRX and STI blocks as they are both open deck.
Differences are in pistons and valve train on the heads.

This is the same with all cars up until the 2.5 sti was released. The 2.5 STI is obvioulsy a bigger capacity and is of the semi closed deck variety.


I think I've got that right.

Daz

Slowboy Racing

The early new age sti also had a semi closed deck iirc