4 banger in SVX...?

[VICSVX]

has anyone put a STI engine in the svx?

im curious if the 2 extra pistions the SVX has makes much more difference if turboed vs an STI transplant...?

any ideas?

[BoxerFanatic]

I have an EJ255 turbocharged Legacy GT, as well as an SVX.

The turbo engine will be much quicker than a stock SVX, or even a lightly modded one.

But it won't be nearly as smooth. It won't pick up right from idle, it will lag just a bit.

You will have to either fit an intercooler under the low hoodline, with a scoop, or do a front-mount with lots of pressurized plumbing.

Theoretically it is capable of producing a lot more power than a non-pressurized H6, and possibly be a touch lighter.

But it will be an entirely different character. A rush of accelaration, but requiring a higher gear ratio to keep the engine near boost at cruising speed. Probably need a 3.90, 4.11, or 4.44 final drive swap... and I would figure that you would be doing a manual gearbox swap, as well.

It won't be as effortlessly smooth as the H6.

To turbocharge an H6, it would need to be re-built with proper low-compression pistons, probably forged rods, and proper cams for that setting. Theoretically, with a lot more work, a turbo H6 will put out more horsepower than a turbo H4, probably by a significant amount. But since it isn't factory, will take more work.

An H6 with 6 low compression pistons will be less lag-prone than a turbocharged, low compression engine with 4 low compression pistons. That many liters of displacement increase (roughly 800ccs difference) will push more energy into the exhaust for a turbo to spin up faster, as well.

But you have to fit a turbo under the hood, in addition to fitting it to an engine that doesn't come with a 'snail' from the factory.

Either way it will likely be an undertaking, and require some mixing and matching of parts and fabrication.

[VICSVX]

yeah there will be an 6spd swap...

i was just curious cause i want to turbo my car and i know it would be easier to put an STI engine in rather then turbo the H6....but i wasnt sure about the performance.

so you're saying that a turboed H6 will be better in the long run.

i was just looking around at options...the price to turbo the H6 is exspensve but i wasnt sure if it would be worth it compared to just swappin an STI 4banger in it.

ive been trying to get prices for the parts (pistons, rods, ect) so i can get a price estimate and where to get them. i know 8 or 8.5 compression pistons...but not sure on anything else like turbo, injectors, crank, cams ect.

my friend has a garret 60 trim he wants to sell me....but idk if it'll work with my car?

[BoxerFanatic]

It depends.

an H6 will be more powerful, if built well. But it also will be more custom, and not have parts right off the shelf.

It depends what your budget, and your targets are.

Another thing, with a boxer 4-cylinder... you might look at the 2010 Legacy's turbo layout.

The turbo is mounted low in front of the engine, with equal length runners from the exhaust ports. Cutting a 6-cyl engine car down to a 4-cylinder engine, and keeping the flywheel in the same place... there will be some room in that engine bay, in front of the engine, for just that sort of turbo location.

The '10 Legacy engine has some other differences, though. The engine mounts are relocated, and the whole engine is mounted in a cradle, which is different than the previous Legacy, and the Impreza lineup. You might need to confirm whether the Impreza or pre-'10 Legacy style EJ blocks, with the previous engine mounting location that is more like the EG33, whether that can accept the low-front turbo headers and other hardware, or whether things need to be fabricated.

There are options, but it matters what your financial and power output goals are.

I would be reading every thread in the Turbo/Supercharger mod forum. ECUtune, and the Toms, and others know much more about the mechanicals. I am familiar with the driving characteristics, but I have not done an engine swap, nor built an EG33 for turbocharging.

[VICSVX]

ok, i'll iook at those guys again...and i'll ask tom about it.

i will also do research on the new subies while im out and about.

thanks

[subbieatnz]

Originally Posted by BoxerFanatic

It depends.

an H6 will be more powerful, if built well. But it also will be more custom, and not have parts right off the shelf.

It depends what your budget, and your targets are.

Another thing, with a boxer 4-cylinder... you might look at the 2010 Legacy's turbo layout.

The turbo is mounted low in front of the engine, with equal length runners from the exhaust ports. Cutting a 6-cyl engine car down to a 4-cylinder engine, and keeping the flywheel in the same place... there will be some room in that engine bay, in front of the engine, for just that sort of turbo location.

The '10 Legacy engine has some other differences, though. The engine mounts are relocated, and the whole engine is mounted in a cradle, which is different than the previous Legacy, and the Impreza lineup. You might need to confirm whether the Impreza or pre-'10 Legacy style EJ blocks, with the previous engine mounting location that is more like the EG33, whether that can accept the low-front turbo headers and other hardware, or whether things need to be fabricated.

There are options, but it matters what your financial and power output goals are.

I would be reading every thread in the Turbo/Supercharger mod forum. ECUtune, and the Toms, and others know much more about the mechanicals. I am familiar with the driving characteristics, but I have not done an engine swap, nor built an EG33 for turbocharging.

Heres a bit more info about the 2010 Legacy diffences

[quote author=boostin link=topic=3189.msg71174#msg71174 date=1250934426]
So I was on the new model training out at Subaru NZ this week. Some trick new features like auto wipers and headlights, electric (and semi-automatic) parking brake, keyless and remoteless entry and start.

There's 2 new transmissions. A CVT, very bulky so the trans tunnel has been reshaped. We got to strip down and rebuild a CVT twice. Actually very simple inside. The 2nd is a new 6MT, based around the old 5MT. New mounting points and cable shift, so no retrofit to older models. We stripped down and rebuilt the 6MT too. The engine now mounts to the crossmember at the middle front, under the snout of the crank and ties back to the trans. The trans then has an outrigger on each side and the standard rear mount. This is to allow the engine to collapse back under the cabin in a frontal. Engines will be easy to get out, clutches etc however will be a *****.

http://www.youtube.com/watch?v=EI1-7...eature=related

Mega amounts of legroom in the rear, and plenty of front seat adjustment also. The CVT is really nice to drive. once the torque converter is locked up its a solid mechanical connection between the engine and the wheels, so no losses like a standard auto.
[/quote]

[quote author=boostin link=topic=3189.msg87924#msg87924 date=1255423137]
[quote author=Old Skool Subbie link=topic=3189.msg87788#msg87788 date=1255391909]
[quote author=boostin link=topic=3189.msg71174#msg71174 date=1250934426]
So I was on the new model training out at Subaru NZ this week.

The 2nd is a new 6MT, based around the old 5MT. New mounting points and cable shift, so no retrofit to older models. We stripped down and rebuilt the 6MT too. The engine now mounts to the crossmember at the middle front, under the snout of the crank and ties back to the trans. The trans then has an outrigger on each side and the standard rear mount. This is to allow the engine to collapse back under the cabin in a frontal. Engines will be easy to get out, clutches etc however will be a *****.
[/quote]

Ive got a couple of questions about this..

Would a earler EJ20 still bolt up to this new transmission?
It will bolt up but the trans won't fit your mounts and the shift mechanism is now cable instead of rod.

Being this transmission is based on the 5 speed would it mean the gearbox would not be as stong as the earlyer 6speeds?
Correct. It will be the same strength as the existing 5 speed.

and is the V11 WRX STis still have the older type 6speed or are they also fitted with the new 6speed thats in this new shape legacy?
STI's get the "good" 6 speed AFAIK, not this one.
[/quote]
[/quote]

[BoxerFanatic]

Yeah, we have had a little go-round over at LegacyGT.com about the new car's features, and the "new", less impressive 6-speed.

I would think that the best gearbox for SVX use would be the VTD, NON-DCCD unit found in the 2007-2009 Legacy GT Spec B, or a similar one from a WRX STI... if any were equipped without DCCD... (although more difficult to implement, having DCCD in an SVX would be very cool, though.)

That should mount up to any EG33 or EJ-block 4-cylinder before the '10 Legacy, or even the current GR Impreza, which hasn't converted to the newer mounting configuration yet.

The theoretical question then would be... if the equal length headers and front mounted turbo will fit on the engines that have the older-style mount points. If someone were to want an H4 Turbo swap into an SVX... it seems to me that would be the layout to try... and feed to a front-mount intercooler. One could even set the radiator back a bit to fit a FMIC in front of it, or plenty of space to plumb in an air-to-water intercooler.

Plus, if one were to use a Legacy/WRX intake manifold, I think those can be run backwards, and face forward and right, to pick up the charge pipe with a minimum length of run. the low mount turbo is reputed to have better lag characteristics, by not having the long, wrapped around exhaust tract, for a short path. Having a similarly short path on the compressor to throttle-body side would also keep the response nice and quick, instead of wrapping all the way around the engine.

Would be an interesting setup, but part of the appeal of the SVX is the smoothness of the H6 engine, even in non-pressurized form. I am not sure I would go with an H4 turbo transplant lightly.

[odepaj]

Just so everyone knows:

Mounting any engine into the SVX will still have tight clearances between the back of the block and the firewall. So plan on designing your own turbo plumbing with either engine (EJ/EG/EZ).







Dustin