Closed deck question
 

What is the difference between closed decks, semi-closed decks, and open decks? Also, what is the estimate amount of boost an EG33 can hold without getting sleeved?

So far the highest I've heard of is 12lbs of non intercooled Supercharger (LANs Stage III)

Decking
 

Closed deck is a plate that surrounds the entire cylinder connecting the cylinder to the block wall. A semi closed is connected in only a few stratigic places. Open is what we have. Connection in only two places.

How much boost the SVX can take "reliably" is a tough question. I wish I knew the answer to that. I think closed decking would add a degree of reliability. But done improperly could make matters worse. There used to be speculation that the old 2.2 liter needed closed decking for boost levels over 7 psi. Hence the turbos had it stock in the motor, along with oil squirters. I think that is BS though. Look at the 2002 WRX boost levels at around 13 psi. No trouble there. They semi close the deck of the STi. They are running boost up to about 17 psi I think. They also have slightly higher compression, although that is not the case anymore with the 2006 WRXs. But again these are all completely different from the SVX in compression and boost levels.

I also think that a good top and bottom grooved piston o-ring and metal gasket would help reduce cylinder walk, without the complicated installation of decking. We shall see how reliable our motors are with all of the additional boost we are throwing at it.

No one really knows for sure, but like mikecg said lans running 12 PSI on a completly stock block. I really dought that the open block configuration is going to be any kind of limitation untill you get to the 20+PSI range. There are many people over on nasioc that are pushing the open deck ej205 past 20 PSi with no problems, and there are people pushing 30+PSI(500whp) on stock STi semi closed blocks with no problems(with a good tune). I belive even Gadiel with his 9.6sec1/4 STi is using the stock cylinder liners from the EJ257 and is pushing (i belive) around in the low 40PSI range and (around 750WHP) on a semi closed deck. I really belive that the weaknesses of having a open deck are compley over played by alot of people. Besides I bet if you need to replace cylinderliners, then you will need to have replaced at least the pistons and probably rods before you will be pushing enough boost to oval the cylinder walls.

Cdigerlando the ej22t that was used in the first gen legacy was an closed deck block, and is considered by alot of people to the strongest block subaru ever made.

ej22t
 

There is a big debate at Nasoic about the actual reliability of this block. Also about the oil squirters, and their affect on overall oil pressure when in use.

If I can ever figure out how to hack into LAN tunning and start to play, I can tear down my spare EG33 and see what kind of boost the motor will hold with some different pistons. But without being able to tamper with it, I am shooting blanks

Tom

FI lightened = race car!
 

Sorry to highjack the thread with this discussion but I would just like to respond.

That is what I like about having stand alone. Its a pain to set up, but I can do just about anything with it. I will be trying to slam it with as much boost as I can. I'll tell you what though. If LAN was able to make power with the advance he was using at 12.5 psi, I think I'm done with mods if I can achieve this too. Really, a turbo putting out 13 or 14 psi at 10:1 compression and 25* of timing is sick. I don't think I'll be driving my WRX anymore.

Tom....I would be very happy with what you have for a while. It is a sweet setup, and a lot easier than the stand alone system. You need to update your installation. I would really like to see what kind of 1/4 mile times you are doing.

Could you imagine this car with FI and a 6MT? It would be really sick. Then throw race fuel in on race day, and the race fuel map. It would be unbelievable.

Yeah well, there are still small bugs Mike and I are working working out. Seems like there is something going ary with my car. It is running well don't get me wrong but I am losing power at some point and Mike and I are trying to find out why. Without a wideband or a select monitor I am really shooting in the dark, I gotta see if I can pick up the select monitor from svxfiles

Tom

oh, and 12.5psi with my 6mt is a ton of fun:D :D :D

Let me know when u ditch the auto;)

Tom

What about dropping the compression. I did a search but the stuff sounded like opinions not "This is how it is" Would it be possible to bore out the cyliders by 6.6mm, add a 4mm iron sleeve, and then use stock sized STi pistons (99.5mm)? Do STi pistons connect to the rods the same way as the EG33 stock pistons?

Possibilities
 

Anything is possible. It may have even been done. I have heard of it being, but just not confirmed it. Its kind of a lot to go through for a perfectly good engine, that already has .8 l more displacement than an STi.

I have 13 psi and a 5 speed. Just not on my SVX:p . The level 10 is great too. Shifts quick. No boost drop during shifts. It might even make a better 1/4 mile car with this tranny. We shall see. I probably would have gone with a 6MT if it wasn't so damn expensive. Also, they were not invented in 2001 when I had my tranny done.

I don't think that he is looking for more displacement, but rather the ability to upgrade his pistons

custom forged aluminum pistons are readily available in almost any size and any specification these days. If it could be done it would be a neat project to see though. Its just expensive.

The block it self is know to very strong, just the internals arent up to what the new ej2x7 motors have. Dident the ej22t have a shimined oil pump to increase preasure for the oil squirters.