4x4dave

Not a turbo expert, but you'll want to shoot for a turbo with a lower A/R number for better torque and quicker spool-up. With a high A/R number, the turbo's peak power may not not kick in until much higher RPMs. Being a 5.4, and not a high revving engine, you want to make the power down low, unless you wana tow at 5000RPM @ 20psi, which i do not recommend

IF your going the TT route, it may be best to do a sequntial TT setup. One turbo should have a lower A/R number, so it will kick in during semi spirited driving, the other should have slightly higher compressor A/R # so it will kick in under maximum throttle and higher RPM's, it will still spool up very fast with the help of the first turbo, but it will net more power than the first turbo. The benefit of the second larger turbo, is that it will not spool up unless your stepping on the pedal pretty good. It also makes for a more linear and uniform power band having two different sized turbos.

You'll want to find out the specs on your turbo, ie compressor, turbine, and A/R values for both housings. All we know is that you have the t3 flanges which gives us an approximation on the turbo specs. Anyhow I'm curious to see how this goes, I'm no turbo guru, so it will be interesting to learn how to turbo a 5.4 A straight TT setup may be easier, IE hook up identical turbo's to each side of manifold. SQ TT may be tricky...

Also - Hellion at one point made a twin turbo exhaust manifold for the 5.4 / lightning. It might be worth checking out. I don't know any more specifics tho... Lots of decisions to be made!!

ibd2328

iTrader: (2)

I think for the exhaust manifolds I am just going to flip them and point the exit towards the front of the truck. My work on building the flanges tomorrow, just need to pick up some plates of stainless steel (that doesnt break the bank). I hope to do a mock up with some PVC pipe to get an ideal of the angles.

Wolvee

We did this on a my buddy Dans old Saleen with a 5.4 4v. Worked out great.

ibd2328

iTrader: (2)

Thanks Sxyner! Im honestly thinking about using the factory intake manifold and making small runners/velocity stacks to fit on the heads. It would be worth a try considering I can pick up a used aluminum intake man. for 100 bucks

Carcrazygts2

In all reality to make loads of torque down low your going to need turbos that can move a substantial amount of air with relatively low spindle speeds. A great example of these are the K03's used in the Audi 2.7tt for example. They have a relatively small compressor housing, but a decent sized exhaust housing.

I wanted to build a TT 5.4 4wd, but the card never played out right. If I was going to do it I would use K04/K05's. This will provide enough air volume to feed the 5.4 with relatively midrange boost figures. I believe with the right tuning a decent set of cam similar to the ones I use, would really net a lot of low end torque with boost. The last time my truck saw a chassis dyno it made peak torque roughly @ 2600rpms and held it all the way to 4400. It only dropped 10 ft lb over the entire curve.

Also a single can accomplish the same thing but will require a very well matched setup to make lots of torque down low without running out of air up top. Price wise a single will be cheaper but I dont think you'll be completely with how the power is made.

Heres how I would assemble a setup.

K04's 3" Down pipe
SHM/Comp custom grinds
Stock manifold- Help make TQ down low
9.0:1 CR- Still be pump friendly and will allow you to safe run 12-14psi (which is the sweet spot of a stock K04)
2.5" intercooler piping
Bar&Plate intercooler.

ibd2328

iTrader: (2)

Its kinda ironic you mentioned the K03's out of the 2.7 From my simulation and simple math, dual turbos (2.7 *2)= 5.4 would produce the best possible boost for my setup.

I may start out with a single K03 or T3/T4 to check the mid-range torque and go from there. I know my top end with fall out quick, I just need to set up my waste-gate so I dont over spin the thing at 4k.

Thanks for the input... I have a feeling I will be asking you alot of questions over the next few weeks. If I can get 475torque at the wheels with single that may be what I stick with. I doubt I will get that with a single T3/T4... Definately not with my 35's on the dyno.

ibd2328

iTrader: (2)

I think staying with the factory intake manifold is what I am going to do, but I thought about adding runners/velocity stacks under neath the factory mainfold. It would honestly just look like 8 stacks of tubular piping holding the manifold up. They tapper off at the bottom (near the heads) to increase the velocity of the air into the chamber.

Carcrazygts2

If you plan on going with a single you may need something bigger than a single K03. The K03/4/5 are all twin setup turbo's ranging from 2.7 to 5.0liter Audi's. I would do twin K04/5's. The midrange will be extremely strong and you really wont spin them incredibly hard. I have seen them being pushed to 8k rpms. So turning them to 4k-5k will be nothing. It will allow you to run a smaller intercooler with out building up excessive heat because they will stay in their respective effiency range.

With twin K04's hitting 500rwtq will be no problem @ 14psi. I have a friend who runs a 2.7 TT S4 with K04's and makes 460 AWTQ @ 18psi. So suplly them with more flow from a larger engine will just get them in there sweet spot slightly quicker. I have a few calculators at my disposal and will see how well the factory turbo map will work with a 5.4. Also cam choice will have a huge dictation on how the turbo will react. With a stock cam I'm sure peak torque will be made really soon but the top end will be limited by stock components. With 14-16psi i can forsee 475-500hp to the wheels and around 500-530tq to the wheels with mostly stock stuff.

ibd2328

iTrader: (2)

[MENTION=52877]4x4dave[/MENTION]

I def dont think I will be doing the sequential just yet.. It would be ideal for my application but I dont think I am up to that task yet. Will either be goig with two smaller/mid sized turbos, or buying a 76mm. Hope to get some things plumped up today with the headers and make some flanges.

ibd2328

iTrader: (2)

Manifold
Gaskets are here. Tryin to get the old studs out as we speak