Twin Turbo sensible?

[6.9poweredscout]

Hello again,
i was talking to a friend tonight and i told him that the banks kit was $2200, he said we can probably get 2 GOOD t-3/t-4 turbos and fab it up for around $2000. would it be worth it to build it to a twin turbo, use stock manifolds and make up pipes to feed them, then dual 3-4" exhaust to the stacks. i figure i can push 20 psi, i'm studding the heads, but don't know what i can SAFELY push a 6.9 to. i plan on getting a Moose pump, and upgrading any weakpoints. will dual t-3/t-4 turbos be big enough for a 6.9? what would be the weakpoint in the engine that would quit before the rest. i'll upgrade whatever necessary. any tips, thought, ideas?

Thanks!!
-Jon

 

[FordGuy100]

I would think you should do it kinda like Flatlander did, and use a psd turbo for the bigger turbo. Then use a small wastegated turbo, like banks or ATS use for our trucks, for the small one . If you rig it up that way you can have a bunch of boost, and have way low EGT's. Hopefully he will post and tell you about his setup if you dont already know about it. And yes it will probably be cheaper.

 

[Diesel JD]

You do have studs right? Any other mods to the engine? You could probably make 15-16psi all day on a built, studded 6.9 and not shorten its life much at all, but that's just a guess.

 

[82F100SWB]

I suggest you have a look at my old posts in the last big parallel turbo thread, parallel twins are entirely doable, and dual T3/4s would be plenty.
http://www.oilburners.net/forums/showthread.php?t=18059&page=2
I run 15 psi all day on a stock, 170K mile 6.9, when it's above freezing... The colder it gets, the closer it gets to 20... A studded engine should handle 20 without a drop in compression.

 

[Darrin Tosh]

A studded engine should handle 20 without a drop in compression.

Check with Flatlander about that,..

I would like to see a twin turbo, one for each bank of the motor but is it really sensable, Hell No, but would it be cool,.. HELL YES!

 

[6.9poweredscout]

got the head studs, getting the pistons ceramic/teflon coated, bored 20 over. yes, i'd like 2 of the same size turbos and not one feeding the other, that seems a little more difficult... he said he thinks it'll build lots of torque right off the idle....that's what i want too! should i use the stock manifolds, or make headders? thinking about it, it doesn't seem too hard to do. plus not only will it be different in a scout but it'll be reallllyyy custom!!

other then the headgaskets (studded heads) what would be the weakpoint, or i'd be ok keeping it under 20 psi??

-Jon

 

[FordGuy100]

Oooh, when you said twins I thought of sequential turbo's. But yeah two of the same sized turbo's on an engine feeding off each cylinder banks would be pretty dang cool. I suppose you could make headers would probably be the best choice actually. I dont know how much room your scout has in the engine bay, but with the exhaust manifolds exiting out the rear that would probably cause some clearance issues if you were to run twins. So if you could fab up some headers to exit towards the front of the engine that would probably be the best. How much room do you have in the engine compartment? I would say you should just limit boost to around 15-16 psi max just to be on the safe side, but I think you should be able to go up to 18-20psi but that is unknown territory and I dont know how these engines like it with that much boost.

 

[Michael Fowler]

The link had a another link all about building headers. The method used was to use weldable schedule 40 pipe fittings. The writer said they were cheap. I checked McMaster Carr and those fittings are about $10 EACH. There has to be a cheaper supplier!

 

[flatlander]

Who care's about sensible? Wear sensible shoes if that's your goal.

The problem as I see it with what you want to do is finding a location to mount the turbos. I don't know if you have to have equal length piping or if you can just do whatever. Do some research, build your truck and then come to pennsylvania and let us all see it over the 4th next year.