Why Do Subaru Engines Knock??!
07 November 2016, 01:16 PM
#41
Scooby Regular
Thread Starter
07 November 2016, 01:34 PM
#42
Scooby Regular
Join Date: Oct 2016
Location: Pinching one out
Posts: 561
Likes: 0
Received 0 Likes
on
0 Posts
Head lift causing gasket to blow out
Dodgy map
Dodgy pistons (ringlands)
Thin liners
not heard crank case flex before, but i can imagine someone has some point down the line. But i can't see that being the issue, there are standard blocks, rebuilt with decent rods, pistons gasket and head studs that are out there running mid 400's for years without issues. Not to mention Closed deck converted that are well over 500bhp, which wouldn't solve that issue if it were a problem.
But put it into perspective, 450bhp (which is widely regard as a reliable level on a stock 2.5 bock) is 150% of the original design spec. Not bad going
07 November 2016, 03:57 PM
#43
Been various suggestions as to why the 2.5 suffers so many failures.
Head lift causing gasket to blow out
Dodgy map
Dodgy pistons (ringlands)
Thin liners
not heard crank case flex before, but i can imagine someone has some point down the line. But i can't see that being the issue, there are standard blocks, rebuilt with decent rods, pistons gasket and head studs that are out there running mid 400's for years without issues. Not to mention Closed deck converted that are well over 500bhp, which wouldn't solve that issue if it were a problem.
But put it into perspective, 450bhp (which is widely regard as a reliable level on a stock 2.5 bock) is 150% of the original design spec. Not bad going
Head lift causing gasket to blow out
Dodgy map
Dodgy pistons (ringlands)
Thin liners
not heard crank case flex before, but i can imagine someone has some point down the line. But i can't see that being the issue, there are standard blocks, rebuilt with decent rods, pistons gasket and head studs that are out there running mid 400's for years without issues. Not to mention Closed deck converted that are well over 500bhp, which wouldn't solve that issue if it were a problem.
But put it into perspective, 450bhp (which is widely regard as a reliable level on a stock 2.5 bock) is 150% of the original design spec. Not bad going
Read the link on post #32, good explanation of why 2.5s fail.
07 November 2016, 04:38 PM
#44
Scooby Regular
Join Date: Oct 2016
Location: Pinching one out
Posts: 561
Likes: 0
Received 0 Likes
on
0 Posts
The article doesn't make sense, not as to why standard engines fail. It's all about people pushing it too far. So it's not really a valid point, apart from the pistons, which are ****.
I do like how they describe closed decking as welding in inserts hahaha
But it basicly says what was said before. 2.5 is good for about 450, CDB it and 550, beyond that liners are too weak. (two threads going at the min about this lol)
I do like how they describe closed decking as welding in inserts hahaha
But it basicly says what was said before. 2.5 is good for about 450, CDB it and 550, beyond that liners are too weak. (two threads going at the min about this lol)
07 November 2016, 05:07 PM
#46
The article doesn't make sense, not as to why standard engines fail. It's all about people pushing it too far. So it's not really a valid point, apart from the pistons, which are ****.
I do like how they describe closed decking as welding in inserts hahaha
But it basicly says what was said before. 2.5 is good for about 450, CDB it and 550, beyond that liners are too weak. (two threads going at the min about this lol)
I do like how they describe closed decking as welding in inserts hahaha
But it basicly says what was said before. 2.5 is good for about 450, CDB it and 550, beyond that liners are too weak. (two threads going at the min about this lol)
It makes plenty of sense, and says the conservative tuning limit is 340hp not 450. Poor piston material and design plus a poor original ECU map is why so many completely standard 2.5 engines have failed. My local specialist is up to his eyeballs in failed standard 2.5 engines, mostly with broken ringlands.
07 November 2016, 06:14 PM
#47
Scooby Regular
Join Date: Oct 2016
Location: Pinching one out
Posts: 561
Likes: 0
Received 0 Likes
on
0 Posts
It makes plenty of sense, and says the conservative tuning limit is 340hp not 450. Poor piston material and design plus a poor original ECU map is why so many completely standard 2.5 engines have failed. My local specialist is up to his eyeballs in failed standard 2.5 engines, mostly with broken ringlands.
But that article isn't talking about standard engines with alot of the points it's making.
09 November 2016, 04:25 PM
#48
Scooby Regular
Join Date: Oct 2015
Location: bham
Posts: 62
Likes: 0
Received 0 Likes
on
0 Posts