CG Weight and balance, Turbocharger location/positioning

[AaronL]

A question for the turbo guys....
Before I start building headers for my boat, I'd like to hear some opinions from people running twin turbochargers on where to position the turbochargers. I've noticed that almost all of them are positioned at the rear of the engine. Does it matter that much, looking at it from a center of gravity/leverage arm standpoint? Obviously it makes it easier and cleaner to plumb the intake charge pipes, but I want to know if it is better to have them rearward for Center of gravity and balance reasons.
I am going to be running a single plane dominator intake manifold (460 ford) with one of my sheet metal intake elbows (like in the attached picture, but a forward or rearward facing). The reason I'm asking all of this is because I'm thinking about putting my turbocharges quite a bit forward from the center of the engine. To make the setup look best, I would like to have the turbochargers placed with the exhaust housings sitting right about even with the timing cover. This will give me enough room to make nice looking 'Y' pipe into the throttle body. They weigh 70 lbs. each, so along with external wastegates and the rest of the plumbing, this could be a substantial amount of weight.
http://intakeelbows.com/DSC03464.JPG

[Unchained]

I put mine behind the engine and lined up the center of the turbos perpendicular to the engine. That gave me good access to the valve covers and aimed the compressors forward. Piping to the throttle bodies was pretty easy.
I really didn't consider center of gravity when figuring out the location.
If you're useing dry manifolds and turbos you'll want to keep them away from passengers as the heat is a significant factor.
Most of the turbo kits have the turbos mounted right alongside the engine and that blocks access to the valve covers. My turbos are large frame Garretts and they weigh 55# each.
What turbos are you using that weigh 70# ?

[The Doctor]

Consider your space constraints.
Will your placement negatively effect your seating arrangement?
Ours are to the sides and we like them there.

[texas-19]

Nice job on the intake,those welds looks good.
If you put the turbos in the front your gonna have to worry about the heat from them while your driving and when your in the boat and trying to move around you'll have a chance of getting burned.The exhaust will be over the valve covers and their will be alot of heat around the intake manifold area.
I moved my engine forward 4" and mounted them in the rear.
I've had it to triple digets and so far it has been very stable.
It sure is nice being able to check spark plugs and remove valve
covers without removing exhaust.

[AaronL]

I'm using two new Garrett Variable vane turbos that are for the newer 6.0L powerstrokes.
I'm only going to be running two seats.
I get burned pretty much every day welding, so no big deal on the heat/burn issue
I want to put the compressor inlets facing forward so the exhaust dump pipes are pointing straight back (for looks).
thanks for the input.

[Unchained]

I'm using two new Garrett Variable vane turbos that are for the newer 6.0L powerstrokes.
Wow, put up some pictures and info about those turbos
I know lots of guys like the exhaust aiming straight back but that makes for a difficult piping situation on the compressor tubes.

[AaronL]

Specs on the turbos :
4" air filter inlet, 4" downpipe outlet, 2.5" compressor discharge, 3" header inlet (with v-band flange, not 4-bolt t-4 style, which is pretty cool). I don't know if you guys have ever heard an '03-07 6.0L powerstroke with straight exhaust, but they sound badass with one of these turbos.
Pretty neat how these work. The exhaust vanes are 'flattened out' to create higher velocity of the exhaust flow into the turbine wheel (at lower rmp) to speed up the turbo rpm. At higher rpm, the vanes open up, allowing more flow. They are controlled electronically, by sliding the disc that holds the vanes in place.
The downfall of these turbos is weight, and you can't clock them exactly how you need them... the vanes need to match up with the control rod, so you have to pick a spot in 40 degree increments (360/9 vanes = 40 degrees) on the exhaust housing.

[Unchained]

That's awesome. I read that those will replace the current turbos eventually.
Do you still need a wastegate with a VVT ?

[AaronL]

On the powerstrokes, they don't use a wastegate..... I'm sure I'll have to use them on my boat setup though. My '05 powerstroke runs 26 lbs boost stock. I'll only run about 12-15 lbs on my setup. Even the older 7.3 powerstrokes with non-variable turbos didn't use wastegates. Computer controlled fuel input (on the diesels) pretty much regulates the amount of boost.

[1968Droptop]

That'll be a sweet set up AaronL. I'm running a straight pipe (4" all the way back) on my modified `97 PSD CrewCab, it does indeed sound sweet. All you hear is the whine of the turbo, very cool cound.
Question for you; how well do you thing the variable turbo is going to hold up ? Those things fail like crazy on the 6.0 ltrs. Got a buddy at the local Ford dealer, they swap out like 15 a week under warranty , and they're a small farming town dealer. I know the variable turbo is good technology, but that particular unit seems to fail a lot from what I've read and heard. Hope you have better luck with your set up.