Yelo

I have decided to go through with the twin-turbo project....

I need to ask a few questions before I finalize a parts list so if y'all can help me out in any way it would be great...

I have decided on using a pair of Garrett TB03 watercooled turbos...7 psi using stock wastegate from idle to 5500 rpm's with no turbo lag (20 psi is possible but VERY unrealistic) and a pair of small air-to-air intercoolers (I decided on two intercoolers for placement reasons and so that the turbos don't "talk" to one another until they mate at the TB) mounted low and in front of the radiator (the radiator will be moved inboard about 4" to accomodate the intercoolers and provide space for routing the turbo plumbing), I plan on mounting the turbos low and underneath the truck (possibly directly off of the manifolds but that is still up in the air) and running the outlet lines as close to the framerails as I can....

My questions are all related to fuel delivery and tuning....

Is a colder plug reccomended on a FI motor??

What injectors would be reccomended for this type of setup ??...given a possible 500 or more RWHP, and what is involved to install those injectors (plug-and-play would be nice but is not necessary)

I am going to have a baseline "generic low performance" turbo tune done after (or possibly during) the install so that I can drive the truck once the install is finished....where whould y'all reccomend send the ECM to get the initial tune done ??, and what information will they need to properly tune for the turbos ?? (I am assuming I will need to finalize my setup before I send the ECM out to be tuned)

Once I have the setup completely installed and the "generic" tune done where would you reccomend taking the truck to get the final power tune done...someplace in SoCal or Nevada would be nice but I am willing to drive as far as DFW if I have to

Will I have a problem during the summer in Death Valley ??....Summer temps typically exceed 120 F during the day, will I need to reduce boost in the summer or retard timing to prevent knock ??

any and all help is greatly appreciated.....if this post will get more exposure in another forum feel free to move it

Hit Man X

No turbo lag is going to be sorta tough to do. If you run a turbo too small, it will just spool right up and out of its efficiency range. For example the turbo on my WRX is a TD-04 and will reach full boost (13-16psi) around 2500-2800rpms with a full exhuast. But that is pushed with a little 2.0 motor. I think a bit of lag is going to be okay...hell just get a stall converter!

Now if you tossed that turbo on a 6.0 (3.0L pushing each turbo) it would spool pretty much right off idle and would be running too fast to make much more than 7-9 psi. BUT, that may be okay for you as you are going to be limited to 7psi. It would be a trick to figure out the wastegates on a tiny turbo with lots of displacement.

Have you considered running a single larger turbo? Like around a .63-70 A/R. That would probably take a bit more to get spooling (2600-3200rpms) to hit full boost but your 6.0 has a lot of exhaust flow to spin a turbo that size and the larger size will be more efficient with its boost (cooler boost). You could also then get a used Duramax front mount intercooler for ease of install too.

If you keep stock manifolds I'd get them extrude-honed to flow more. Remember you want smaller primaries to help the turbo spool up initially, then a monster 4" downpipe to get rid of that stuff. I would probably get a set of shorties and have the Jet Hotted to keep the heat in, as heat = initial spool on a turbo.

I'd for sure run a set of cooler plugs, one heat range should be enough. Injectors around 42lbs/hr should be plenty large for your 7-9psi setup.

Also the temps in Texas hit the high 90's easily and my WRX still runs the same boost. The computer pulls timing as boost pressure increases to keep from detonation. It is also intercooled.

Hope that helps some...

OOsilverado

If you want to run turbos down low, get ball bearing turbos, you will have oiling problems if you mount them low.

Also Id go bigger on the turbos, there will be lag no matter what. If there is no lag, then your turbos arent really making much power. Go buy corky bells book, maximum boost. That will help you out a lot in turbo selection and things like that. I was planning on doing this for a long time, then stopped and keep tossing the idea around in my head. I was going to use a set of T4s. Make sure you dont go to small on the turbo, because if you do, things will get very hot very fast. your better off going a little to big than a little too small. especially in the desert. bigger turbos will keep everything much cooler

parish8

iTrader: (6)

about your tuning questions. you wont need to do any "special" tuning to drive the truck after the turbo's as long as you dont get into very much boost. just drive it real easy till you get it in to get tuned. if your handy and somewhat computer savy i would tune it yourself but you need about $1500 bucks worth of tuning tools to do that. good thing is when you get done it will be right, most likely better than any shop could do in an afternoon and if you make changes you will have the tools to do it again. there is a section in ls1edit where it pulls timing based on intake air temps, with a turbo set up and death vally driving planed you might want to increase those numbers a little so it pulls pleanty of timing. if your handy enuff to get a twin turbo set up bolted onto your truck you are more than able to tune it your self. these tuning tools will most likely work on future cars too.

go with the TR6 plugs, thats what most FI guys go with.

the bigest injector that will actualy bolt/plug right into your truck may be cutting it a little close for your set up. they are the 42lb/hr at 58psi and they would be good for about 500fwhp if you go 90% duty cycle and .60BSFC. i would go for some 50lb units(thats 50lb/hr at 43.5 psi so more on your truck). those are more like 57lb/hr at 58psi and good for close to 700fwhp using the same asumptions as above.

XLR8NSS

iTrader: (4)

I've heard from a relatively reliable source that the 57'b/hr Siemens injectors are easy to tune and much better then the 50lb/hr injectors. I don't know first handthough.

I will be swapping a set of SVO 42# injectors in this weekend and will make a post on how to do it. So far it's been very easy and I know the injectors work well since they were in my car.

If I were you I would buy LS1edit first and get used to it before attempting a project like this. In ethe end if will be better since oyou wont have to send your PCM out if the tune is wrong but, it will cost more up front.

John

PS- Please excuse any errors in my post.

parish8

iTrader: (6)

hey John, do they really sell 57lb/hr injectors? so 66lb/hr at 58psi, or close to 800hp!! hmmm.

another injector question, might have to toss this one in fueling, do the huge low impeadance injectors control the fuel any better or have a shorter offset then big high impeadance injectors? hmmm. or does the fine control continue to get more dificult as they just keep geting bigger even though they switch over to low impeadance. hmmm.

Yelo

Hit Man X....I pretty much want to limit total boost to 7-9 psi and eliminate as much lag as I can so the TB03's look pretty good to me. I realize I will be making that boost at idle with 3.0 liter blowing into each turbo....and since I won't be spinning more than 5500 rpm's I shouldn't have a problem with overspooling them (the new Bentley Arnage is using a pair of the same turbos on a 6.75 liter V8 with VERY good results)

00silverado...I will definitly look into that book before I purchase anything (especially the turbos)....I will look into the bigger turbos but given the restrictions I am placing upon myself I am pretty certain that the TB03's are the way I am going to go. How low can I mount the turbos before I run into oiling problems ?? (I am mounting them above the oilpan...is that still too low ??)

parish8...I will skip the "generic tune" and just drive sanely to the tune shop once I get the turbos installed.....I am actually going to build the turbo setup as a modular drop-in setup....hopefully I will be able to "build" it off of the truck and then just bolt it into place and route the plumbing, that way I can go back to stock without a problem...the only caveat will be the fuel rails...but if I can build modular plugs into the injector harnesses I should be able to return those to stock easily enough too. and I may do the tuning myself if I feel comfortable doing it (computer savvy is an understatement...that's my career)

XLR8NSS...the 57 lb/hr Siemens injectors sound about like what I am looking for....do you have a $$$ amount for them or a place that I can find out a $$$

XLR8NSS

iTrader: (4)

parish8 - yep, 57lb/hr @ 43.5psi. Here is a link. I've heard that idle is the big issue with BIG injectors but, I read about a very easy way to take care of that with LS1edit. Let me try and find that thread again.

http://www.racetronix.com/Racetronix..._Sale-55h.html

Yelo - See above