Brainstorming an original EG33 turbo configuration

I have dreams about a twin turbo SVX and I'm determined to find a way to fit them. When I say dreams I mean I actually dream about seeing my hands on the wheel, seeing the SVX gauge display and hearing the sweet sound of turbos spooling in the background. This is driving me mad! (in a good way )

I was surprized when I saw a mustang TT kit that has a front mount intercooler w/ the turbos located on / under the front bumper. I've also seen a trubo configuration that houses the turbos in the fender behind the front wheels.

http://www.turbochargedpower.com/

Seeing both of these inspires me to make room for two turbos by doing things like removing A/C components and relocating battery etc. I've even gone so far as to think of fabriacting headers that flow forward to feed the front mounted turbos.

Over the past 10 months I've read a lot about turbo applications to the EG33 and I see that the engine will only accept about 6psi maximum before it starts to fail. I was trying to think of a way to decrease the compression of the engine enough to run higher boost levels.

This is just a pipe dream but this is what I'm thinking: what if, you bored out the cylinders to house larger pistons out of another 24V turbo engine to lower the compression? The only reason I suggest turbo pistons is because I'm assuming that there are differences in construction and / or durability. I've heard that the SVX shares pistons w/ the EJ22. Perhaps the 2.5 pistons will do; I realize that these arent turbo but they will hopefully mate w/ the connecting rod best because they are fellow Subaru parts. I need to look at what clearences I will have to bore around. If this idea is even concievable.

Now I can imagine what a boosted EG33 mated w/ a 6MT would do to this car. It would finally be as fast as it looks!

Like I said, this is just a start but I'd like to hear what others think about this idea. Any input at all would be greatly appreciated.

Thanks!

[SilverSpear]

man you should consider the maximum HP/Torque that the 6 speed also can handle. I am with you on this brainstorming, but what I need to do is make a nice twin turbo SVX "fail free". for the right side turbo, you can relocate the the fuel filter and the coolant box. keep the battery as it is, try to make longer hoses for the filter and the coolant... you will have the other turbo's place instead. concerning the engine, I was wondering about the 2.2 L turbo Valves, are they the same as the SVX ??? the pistons are, but what about the valves ?
I was talking to a friend of mine in Florida, he will maybe send me a complete (broken down) SVX to Lebanon. If I get my hands on its engine, I promise you guys of an SVX made by a Demon !!!!

[SVXer95]

When you start to do some major modifications to any drivetrain you can't expect it to be 'failure free'. This is all well and good if you have cash (and another vehicle) laying around in case something happens.

As far as the turbo project goes, has enyone ever tried to bore out the motor? I would assume custom rods and/or pistons would be the easier way to go. In the long run it would probably be cheaper too. I am not quite sure what SVXtasy has done, but he is now boosting.

A complete car from FL to Lebanon, $$$$$$$$$$$$$$$$$!!
Esp. if it isn't running.

[UberRoo]

Going from the 2.2 litre pistons to 2.5 litre pistons is a huge step up. I don't know if the increase is in bore, stroke, or both; but even if it's a little of both, that's still a huge increase in bore. I don't think there's any way to bore the EG33 block that much bigger. Also, will the wrist pin fit? Is it's location correct for the EG33 rod length? Will the dome be clearanced for the EG33 valve configuration? Is the skirt going to interfere with the crank ballance weights or the block internals?

I'm almost certain that no other Subaru uses the same valves as the EG33. The heads on the SVX are totally unique to any other Subaru block. Yes, the bottom end is basically an EJ22 with an extra row of cylinders, but the top end is something else entirely. Custom valves are not difficult to come by, but I tend to think they would not be neccessary.

[SVXRide]

Relocate the battery and pull the ABS pump - should give you room for both turbos. Check into the folks using the 4HEAT in a drag racing environment (think it's in a WRX).
-Bill

[huck369]

Just get pistons out of a 2.2 Turbo Legacy, they are the same size as the 3.3 pistons and are lower compression for the turbo application....

[mbtoloczko]

Twin turbos sound cool, but the reality is that there's not any significant advantage to twin turbos. More heat, more piping, more things to break. As you point out, the OEM SVX motor is probably limited to fairly low boost levels, and twin turbos don't necesarily improve power compared to a single turbo running at the same boost level. Same goes for any SVX motor with a lowered compression ratio. So unless you are just into having a twin turbo, I'd suggest going with a single turbo. You'll have better luck building and tuning the motor.

Also, I'd suggest keeping in mind the idea of using a STi 2.5 motor. Overall, it would probably be less work adapting this motor than it would be building up a proper SVX motor for a turbo. It just doesn't quite have the cool factor of a custom EG33 motor though.

[Chiketkd]

Originally posted by mbtoloczko
Also, I'd suggest keeping in mind the idea of using a STi 2.5 motor. Overall, it would probably be less work adapting this motor than it would be building up a proper SVX motor for a turbo. It just doesn't quite have the cool factor of a custom EG33 motor though.

I'd have to agree. The STI conversion would be a lot more straight forward and less costly. The engine will hook up to our trans (or you could just do an STI 6MT swap as well), and all you'll need to swap out after that is the wiring harness & ECU.

-Chike

the change from EJ22 to EJ25 is an increase in both bore and stroke. Infact, the EJ25 is the only newgen engine to have a different stroke. All the rest are 75mm with just different bores. Anyway Like others have said throw in some EJ22T pistons to get the compression down. I do wonder however, if pistons are all that's required to lower the compression Or if they'll even lower the compression. There could be a difference in deck height, or head gasket thickness, or something that'd prevent the EJ22T pistons from being effective. Like lets say for example the EG33 and EJ22 share the same dimension of pistons, yet the reason the EG33 has a much higher compression is from a thinner headgasket or something, so even putting those pistons in wouldn't do anything. Really that's all speculation though.

About the mounting of turbos, wouldn't mounting them too high just create too much heat too high up in the engine bay? I still personally think a single turbo would be a much easier and better way to go about this. Maybe you should consider that? A nice semi large turbo like a TD04-18G/20G or something?

[SilverSpear]

Originally posted by SVXer95

A complete car from FL to Lebanon, $$$$$$$$$$$$$$$$$!!
Esp. if it isn't running.

why are you surprised ???we do buy over here broken cars, we sell them as parts !! why the surprise? the whole car will cost no more than 1000 $ !!!

[SilverSpear]

Originally posted by UberRoo
Going from the 2.2 litre pistons to 2.5 litre pistons is a huge step up. I don't know if the increase is in bore, stroke, or both; but even if it's a little of both, that's still a huge increase in bore. I don't think there's any way to bore the EG33 block that much bigger. Also, will the wrist pin fit? Is it's location correct for the EG33 rod length? Will the dome be clearanced for the EG33 valve configuration? Is the skirt going to interfere with the crank ballance weights or the block internals?

I'm almost certain that no other Subaru uses the same valves as the EG33. The heads on the SVX are totally unique to any other Subaru block. Yes, the bottom end is basically an EJ22 with an extra row of cylinders, but the top end is something else entirely. Custom valves are not difficult to come by, but I tend to think they would not be neccessary.

this case is done easily in Lebanon !! over here some of the mechanics are experts in engine mods. a friend of mine installed the 1975 Mercedes 450 sel 6.9 pistons in an engine of the 1972 Mercedes 230.4 !!! (i dunno if some of you know this car, still exist as taxis in Lebanon). the car is a monster !!! what a torque !! so I won't have a problem tuning the svx's engine !! piece of cake !

[SilverSpear]

Originally posted by huck369
Just get pistons out of a 2.2 Turbo Legacy, they are the same size as the 3.3 pistons and are lower compression for the turbo application....

AHA !! now the music is starting to rock !!

[SilverSpear]

Originally posted by THAWA
the change from EJ22 to EJ25 is an increase in both bore and stroke. Infact, the EJ25 is the only newgen engine to have a different stroke. All the rest are 75mm with just different bores. Anyway Like others have said throw in some EJ22T pistons to get the compression down. I do wonder however, if pistons are all that's required to lower the compression Or if they'll even lower the compression. There could be a difference in deck height, or head gasket thickness, or something that'd prevent the EJ22T pistons from being effective. Like lets say for example the EG33 and EJ22 share the same dimension of pistons, yet the reason the EG33 has a much higher compression is from a thinner headgasket or something, so even putting those pistons in wouldn't do anything. Really that's all speculation though.

About the mounting of turbos, wouldn't mounting them too high just create too much heat too high up in the engine bay? I still personally think a single turbo would be a much easier and better way to go about this. Maybe you should consider that? A nice semi large turbo like a TD04-18G/20G or something?

I completely agree ! the best thing to do is to hook a large turbo instead of two. I am considering a big Garrett especially that some guy over here is importing it from the States...

[UberRoo]

From a cost standpoint, a single turbo is clearly a better solution. From a performance standpoint, dual turbos is superior. Using two turbos allows several improvements:

* Two small turbos will spool up faster, allowing significantly improved throttle response.
* Having two turbos will allow them both to be placed very near the exhaust manifold, helping to keep them hot and effective.
* Having two turbos keeps the exhaust configuration simple, allowing the heat from the exhaust a very direct route somewhere else other than the engine compartment.
* Plumbing the intake is easier than plumbing the exhaust.

Were it not such a huge and expensive undertaking, I would prefer to have a single turbo for each and every cylinder. Throttle response would be fantastic.


Regarding the EJ22 vs. EG33 motors, I would not be surprised if the only difference in compression ratio comes entirely from the combustion chamber geometry. The EG33 has a hemispherical chamber. Assuming they fit, it's quite possible that using the EJ22T (~8:1 CR) pistons in the EG33 (10:1 CR) would yield a compression ratio similar to the naturally aspirated EJ22 (~9:1 CR.) I think the EJ22T head is different than the EJ22 [N/A] head. The compression ratio difference may be in the head design, not the piston. I would think the cams and valves might be different at the very least, if not the entire head. I do know the 1.8 litre heads were quite different depending on the configuration.

Can anyone confirm if the EJ22 and EJ22T heads are indeed different? Also, what are the compression ratios for all the motors in this discussion? Did they ever change throughout the years? I seem to recall the EJ22 gained a few tenths on the ratio in the mid 90s, netting them a little more get-up-and-go. Perhaps this also happened with the EJ22T? If so, that would indicate that compression ratio is controlled by piston geometry, not head geometry. (That's good for you "just swap the piston" guys.) If the EJ22 and EJ22T compression ratios did not both change simultaneously however, that indicates that the compression ratio may very likely be controlled by head geometry. (Meaning that swapping pistons won't do anything.)

[SilverSpear]

in my opinion the EG33 shouldn't have a compression less than 9:1 , because driving at low rpm the SVX wouldn't have a lot of acceleration as it was especially because of its high weight. so a 9:1 compression ratio, the V1 chip and a nice turbo will do the trick.

So the pistons are accounted for now, but what about the other internals such as the Valves ??? no body is giving an opinion about them