Well, in that we seem to have suffered a little thread divergance here, going from liner issues, to open/closed deck block issues.

On the liner issue, we'd be "encouraging" anyone who was heading out towards 500lb/ft and above, to be installing liners. With safety/reliability margins involved, we'd be advising them to be installed prior to approaching those kinds of figures.


Mike

Looking at the last pic, it's at a thin point in the wall...looks like something has been machined out (see the radius), is that the norm for 2.5L blocks?

Yes, this is normal they have this to enable you to bolt the block halves together. Although this may not be entirely necessary if subaru used a different style of fastener!!

We really must insist their standard blocks are capable of 1000 hp and can hold 3 bar of boost:lol1:

Ah, I see...explains why failure there though, week area in wall as thinner.

This 500/500 mark...would the block last longer with a car running this power level with 1.7 bar of boost instead of 1.9 bar of boost? ie, different turbo, specs, etc, etc? After all, its all to do with pressure per sqaure inch.

Tony,

The relief is where the block is machined to give the block bolts more access room.

Anyway, it appears that whilst the thin 2.5lt liners only play a (relatively small) part in the liner cracking jigsaw, the solution is to replace them with thicker, stronger liners if you want to achieve circa 500ftlbs or more on a 2.5lt reliably :thumb:


The so long as you don't suffer the liners dropping, it should make for a strong engine.


An alternative is to start with the stronger EJ22 closed deck block, and go 2.35lt, which has proven to be very reliable at the higher levels.


If you can keep to circa 450/450, I've yet to see liner issues at this level.


Mark.

Hey Mark,

Is it a boost level issue as well as power level though? Does a 1.7 bar engine have an easier time than a 1.9 bar engine? I know there's alot of other things involved including charge temps, exhaust flow, mapping, coolant temps, etc, etc, etc, all can make a difference.

FWIW... I have been running at 500+ for a while now. My Cosworth built 2.5l engine has done 4k miles now and has been running at a minimum of 500+ of each for a majority of that mileage (80+%).

Just to see what would happen I ran the car at over 2bar peak for around a 1000miles on my AET GT30 standard fit turbo (produced WELL in excess of 500lbft on pump fuel), both on the road and for 2 full track days. No problems what so ever. This is not to say something will not happen at this level of course as 1k miles (even with track use) is not indicative of the term "reliable".

Car is now back to 1.7bar and still producing 500+ of each and that is the way it will stay for the time being.

Regards,
Shaun

2 bar on a gt30 must of been mental!:eek:

Wasn't there a guy who ran 2.8 bar or something on a 2.5 once due to his actuator sticking shut and bent a rod? Some def seem to be lucky and some dont.

Shaun,

Interestingly, I've yet to see one fail with a "bolt on turbo", they have all been with GT30R's, or bigger.

I think the failures have to be put into perspective. There are a number of standard 2.5's running in excess of 500bhp, and even more running in excess of 500ftlbs, that have been doing so for some time/miles.

The law of averages dictate that some engines will run reliably at higher levels, whilst others, lower, but as a supplier, I have to make recommendations that err on the side of caution, and make it clear what the consequences of pushing further may be.


Mark.

Glad to hear it Mark...at least there's some suppliers that tell you "as it is", ie the truth.:thumb:

Tony,
I know a rotated GT35 was run on a 2.5l at over 2bar with no issues at all! That must of been quite quick. ;) lol

When mine was running over 2bar the Defi boost guage was hitting the safety point (i.e. well past the 2bar scale) on the gauge (to stop the spring from been stretched I presume) and resetting the gauge back to zero. Just a tad more than 2bar then. :D

Mark,
Dare I say that is because there are not many 2.5 builds out there with a standard position turbo actually achieving these kinds of torque levels..... certainly no where near as many as rotated set-ups I would suggest.

Out of interest, Anyone know how much power a 2.5 STI8 with JDM Big port head, correctly mapped to 1.9 bar on Tesco 99 ron with GT30R would make?

Car was due to go on the rollers at ESC rr day yesterday, but blew up a week too early :cry:

Would estimate roughly 480-500bhp with a .62 AR exhaust housing, and 500-520bhp with a .82AR.

However, the torque could be far higher, depending at what RPM it was making the 1.9bar.


Mark.

Well at least the estimate we had was good enough!!

If the turbo was changed for say the GT3040, is it possible to get the same power figures at lower Boost?

We tend to find the .62 housing is about 3HP down on the .63 housing, but with a circa 12rpm spool advantage. :hjtwofing ;)

Here we go again :Whatever_

It has the 0.63 housing, but I thought it was just a typo:lol1:

Hofefully should see 503bhp when it finally makes the rollers then:lol:

SSCJAY,
Depends whos rollers you use! :D

The largest GT30 wheel in a standard subaru fitment exhaust housing turbo on my 2.5 gave 440bhp / 465lbft on VPower AT THE HUBS. That is with peak boost of 1.75bar (for torque) and 1.6bar at peak power. My comparisons have found this to be 14% less than the flywheel figures given by Dyno Dynamics, resulting in 501.6bhp / 530.1lbft. In a comparable run on a MAHA showed 523bhp / 525lbft (1.8bar peak boost for torque and 1.6bar at peak power). Regardless of who's rolling road, it's 500+ of each.

If I stuck a rotated GT30 on my car with 1.9bar peak / held with a hot side that could get rid of the gasses quick enough (for top end boost), I would expect a bit more bhp and torque (thats using my build).

As Mark has said 500+ of each should be on the cards in an "all things being equal" equation.

very interesting but to be clear to everyone these big power builds are on built engines with forged rods/pistons not the std EJ257.

** subscribed ** :)

Yes, very true...

Std EJ257 block though, thats the item under scrutiny here !

I have one customer with a 3 year old EJ257 based engine, just dyno'd last weekend at 570bhp and 540 lbft torque on a GT35R running up to 2.2 bar of boost. Its an everyday road car that runs in the 10's on the drag strip.
My own EJ257 has also recorded close to 600lbft torque at 2.4 bar of boost on a MD321T.
One thing these cars have in common is they are not used for Vmax extended top speed runs. I would be dialing in a lower boost or thicker liners for that duty !!

Horses for courses ;)

Andy

Sorry Andy - you are perfectly correct there :D

To be on the 'safe' side, A new 2.5L block will be winging it's way from America shortly, and having top hat liners installed:thumb:

And that hopefully will be the end of the split liner scenario:luxhello:

I'd of gone for closed deck 2.5L but choice is yours...

600 ft/lb off a MD321T at 2.2 bar - wow! :notworthy

That was 2.4 bar:eek2:

And I did say close to 600lbft, 589 to be precise !

Andy,


Please can you make sure you give accurate information in future, I don't want anyone suggesting that we inflate the results we get :lol1:


Mark.

How long would an engine last at 2.4 bar? Mark will give you call regarding the turbo and few ideas suggested by Chy.

Banny

Mark
Better start stocking up on spare engines with everyone wanting 2.4 bar on your turbo's ! :D

Banny,

Not nearly as long as the turbo :lol1:


Alan,

It was ok until that lunatic Forrest started to run 2.4bar, now everyone will want to do the same :brickwall ;)

That said, not had any liner issues with the MD321's yet, but power is rarely above 500bhp, although 500ftlbs + is quite common.


Mark.