looking for setup advice on front mount single/twin turbo lq4

I'm new to the forums, I've already read a couple years' worth of posts in this section and gotten an idea of what is popular for the trucks. I'm no newbie to turbo setups myself, as I build stock and modified mazda rx-7s ranging from 150-600rwhp. I've installed both bolt-on turbo kits and had custom setups made, so I have a good understanding of what does what.

My truck is an 02 Denali with the 6.0 lq4 lower compression engine, runs great and about to turn 80k. This truck has the fulltime AWD, though I admittedly do not know which trans I have, I havent been able to find much info on how to distinguish the 60/80 apart. I already have a walbro 255 fuel pump in the tank. I've also got 24's, a 2/3 drop, eibach swaybars, and the baer 4 wheel brake upgrade with slotted/drilled rotors and SS lines.

I've thought about the sts rear setup, but it doesnt seem like a lot of turbo for the money, you can't really show it off to your friends when you pop the hood, and it also seems like once you start adding upgrades the cost can exceed 6 grand easily. I'm also pretty uncomfortable with the rear mount "oil pump" setup, I mean if that sucker fails then you not only dump oil out the turbo/exhaust, but you probably toast your engine as well.

I figure for less than 3 grand I can do a custom frontmount single or twin turbo setup, with intercooler and piping, and perhaps even water/meth injection, plus dual custom exhaust all the way back. The only hard part for me would be getting the LS turbo headers made, since I cant find any pre-fabbed ones like they make for the mustang guys. I may buy the mustang TT headers and just have the LS style header flanges welded on.

Why do I need twin turbos you ask? Well, I don't, but there's a certain symmetry to the idea on a v8, and it's almost simpler to set it up that way than wrap exhaust piping all the way around the engine for a single turbo. I also figure I can go with smaller, faster spooling turbos for low end response, while still having enough volume for a strong top end. I'm not looking to set any records, but I would like a solid 450-500 crank hp while retaining stock idle/driveability and perhaps even better low-throttle gas mileage, on pump gas. Finally it would be one of the most bad ass sights to see when you pop the hood, and since the rest of my truck is fully built, there's no need to skimp here.

My questions to those in the know:

-what fuel injectors should I look to run? I have heard 42-44lb are popular, I'd like to be able to run as much as 10-12psi on twin t3/t4 turbos, but will probably start out with 6-8psi since the turbos will likely be internally gated. Will my walbro 255 pump be enough?

-if I get a nelson mailorder tune, I assume the crappy 110mph speed limiter can be removed or reset higher?

-if I get a nelson mailorder tune, can I keep my stock computer core? I dont want to have to return it, in case I ever put the truck back stock or need to sell it. Can I pay an extra core charge, or do I need to buy a spare to return after the tune?

-how accurate are the mailorder tunes? I can't go on a 3 day road trip just to tune my truck at a facility, I run a fulltime shop by myself and cant be without the truck for more than a couple of days at most. I am in east TN, for reference.

-with a nelsone tune, can I remove the EGR without getting a code?

-this being a heavy AWD truck, what are the chances of destroying my stock tranny? I wont be raising immortal hell with it, but I want to be able to play around without breaking shafts and such. I already have an 11x13 trans cooler and a recent fluid flush in place, and trans temps never go above 150 in the summer. Again, I dont even know which one I have, how do you identify 60 vs 80 models? What are the options for upgraded trannies and torque convertors for my truck?

-is there any inherent weakness in this engine that'll cause problems? I have read small things about the valve springs being too weak, and others recommend cam replacement and stronger rods/pistons. I prefer not to fool with the bottom end at all if possible. I admit, I would like to be able to rev to 6000 without worrying.

-how important would it be to replace the cam for boost? I wouldnt mind a little lopey idle, but I dont want to shake the truck at redlights or have a surging idle.

-has anyone put an LS style intake with the bigger throttlebody on their truck engine? I know it sits lower and have heard it won't clear the stock accessories, but I wouldnt be opposed to making a bracket or 2 if I can pick up 10 or 20hp. Would the larger throttlebody be a plug and play?

Thanks for any help in advance.

As far as the Nelson tuning. It reads pretty accurate via mail order. If you have any prior knowledge with the software, "HPtuners" then it gets EXTREMELY accurate. You can datalog files and send them to Allen and he can tweak it just right, and send you another tune.

Also, as far as turbos go, Allen and a company called Trick Turbo just came out with a new Front Mount turbo kit for the 4.8-6.0 trucks. Which includes the intercooler and the whole shebang. I'm pretty sure 10-12 pounds can easily be achieved without doing anything to radical to the internals of the engine. Here is a testimonial to a guy that was the guinea pig of the whole project and dropped 3 full seconds off his 1/4 times and is only running 5 pounds of boost on a stock engine with only corsa exhaust.

http://forum.ls1truck.com/index.php?showtopic=9683&hl=

Here is some more information on the front mount.
http://forum.ls1truck.com/index.php?showto...ont+mount+turbo

Hope some of this helps. I'm sure others will chime in soon enough.

-david

First of all, it sounds like you have some really good ideas and the truck should turn out pretty sweet when you get it all together.

The injectors will most likely be in the 60 lbs. range, 48 lbs. worked for me but i am only running 5psi at the moment. Allen should know about the pumps ability level, not positive about that and dont want to provide bad info.

The speed limiter can definatly be removed, in fact, most of the time I think Allen bumps it to like 140ish or removes it all together automatically with the tune.

I think Allen would let you keep your stock core, but I assume there is a core charge. But for your protection Allen keeps a detailed record of the the tunes, including the stock one, and would probably send it to you if you needed it.

Typically Allen recomends at least a shift kit and a servo. But having the cooler will definatly help. In any case when you run that much hp through a stock drivetrain you are bound to break something.

From what i have read and talked to Allen about a "turbo" cam will move your power band either up or down in your RPM range rather than give a lot more hp. Someone with a cam and springs are probably better suited to comment on that though.

I am actually shopping for a larger throttle body myself, so if you find one let me know too! Unfortunatly though from what i have heard there isn't a lot to choose from so you may end up having some guys that would buy it if you made it.

I am not the most educated in forced induction, but i do have a little experience. I just wanted to comment since you had some legitimate questions, and I didn't want ducky to be the only one. hehe Allen would be the best person to chat with and get a good idea of would you are getting into. The Trick Turbo system sofar is awesome, but there isn't really anything that can go wrong with it. good luck

<div class='quotetop'>QUOTE(06z71sierra &#064; Jan 29 2007, 05&#58;56 PM) [snapback]81580[/snapback]</div>

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Allen would be the best person to chat with and get a good idea of would you are getting into. The Trick Turbo system sofar is awesome, but there isn&#39;t really anything that can go wrong with it. good luck
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What&#39;s allen&#39;s username here so I can PM him (does this forum have private messages?)?

I saw pics of the single turbo setup posted above. It looks like it would certainly work, but I must admit that the flow characteristics of the crossover pipe (sharp 90* bends) and passenger side manifold (again 90* turns where the cylinder runners meet the main pipe) leave a little to be desired, and probably leave a little bit of spool and power behind too.

<div class='quotetop'>QUOTE(RotaryResurrection &#064; Jan 30 2007, 01&#58;56 PM) [snapback]81665[/snapback]</div>

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What&#39;s allen&#39;s username here so I can PM him (does this forum have private messages?)?

I saw pics of the single turbo setup posted above. It looks like it would certainly work, but I must admit that the flow characteristics of the crossover pipe (sharp 90* bends) and passenger side manifold (again 90* turns where the cylinder runners meet the main pipe) leave a little to be desired, and probably leave a little bit of spool and power behind too.
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farmtruc, and yes there is private messaging on the boards.

STS reliability - when it works right it&#39;s great&#33; But yes I have seen a couple of failures; one was a turbo failure do to inadequate lubrication (poor oil feed), and the other was total engine failure due to the turbo center section leaking oil into the intake charge; that instance was a bad deal, the owner kept driving the truck (hard&#33;) not realizing there was a problem aside from mysterious uncontrollable detonation on WOT - result was dead pistons/cylinders, dead cats, dead turbo.

RE LQ4 Q&#39;s: good engine, a couple general concerns to address - replacing the stock rod bolts with ARP hardware is cheap insurance and necessity if spinning up into/beyond the 6500-rpm mark (that is a general statement, not a specific one). After rod bolts, the first point of failure is the factory cast pistons, experience has shown the top ring land to fail above the 500+ rwhp mark (give or take) assuming proper tune and no detonation. Again this is a generality; most LQ4/LQ9 guys don&#39;t run more than 8-10 lbs of boost. Going by what you describe 8-9 lbs boost is typical and regarded as very safe for a daily driver on stock internals assuming it is intercooled, tuned properly, and not overreved (won&#39;t happen with proper tune) and will get you well over your performance goals using the stock cam & heads.

Tranny Q&#39;s: you will toast the tranny in short order, the factory 4L60E will not hold IMO assuming we are talking turbocharging because if built correctly the launches will be murder on the trans. You will need a hardened tranny, count on it. With a centrifugal (Vortech, ATI) they are usually not as hard on launch so some guys can baby the tranny but with a turbo that idea is out. The trans in these trucks is the weak point, however they can be hardened to take 600-650 lb-ft albeit you&#39;ll be set back about &#036;2500.

RE AWD drivetrain Q&#39;s: The AWD is actually pretty rugged in these trucks as-is, because of the torque split between four wheels; this is one part of the truck they got right. The rear differential could be a little better quality but generally works well because it is only getting 60% of the powertrain torque output.

Mr. P. :)

Ok, so in looking at popular turbos being used on these engines as well as flow rates, etc. I&#39;ve come to the conclusion that t3/t4 hybrid twin turbos would probably still be too small. Now I&#39;m thinking of twin t04E&#39;s or something along those lines. I want to stay small as reasonable for 1) space and 2) spool.

The more I measure the clearance in the enginebay, the more I see the appeal of a single turbo mounted on the passengers side of the engine. The damned steering column is DIRECTLY in the way of both the turbo header and the downpipe exhaust, were a turbo put on the drivers side. The main engine harness is also in the way.

<div class='quotetop'>QUOTE(RotaryResurrection &#064; Feb 1 2007, 12&#58;44 PM) [snapback]81847[/snapback]</div>

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The more I measure the clearance in the enginebay, the more I see the appeal of a single turbo mounted on the passengers side of the engine.[/b]

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Exactly where Trick&#39;s kit puts it.

<div class='quotetop'>QUOTE(SCIV &#064; Feb 2 2007, 05&#58;24 PM) [snapback]82015[/snapback]</div>

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Exactly where Trick&#39;s kit puts it.[/b]

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:imwstupid: If the turbo is sized correctly there is little performance or lag difference vs. a comparable twin-turbo setup.

Mr. P.

<div class='quotetop'>QUOTE(SCIV &#064; Feb 2 2007, 06&#58;24 PM) [snapback]82015[/snapback]</div>

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Exactly where Trick&#39;s kit puts it.
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So, does anybody know how much this kit actually COSTS, or is it some big secret? The website is basically non functional, which doesn&#39;t exactly inspire confidence in me as a buyer of their product if they can&#39;t even make a website work. When I started my shop years ago I realized that I had to have a clean, functional website in order to project an air of professionalism to get any work.

IF this is some one-off experimental kit, I&#39;m not sure I&#39;d be interested unless the price were very attractive. I mean, I can do "experimental" myself pretty reasonably (as stated above). IF I am paying a lot more money for a pre fabbed kit, it better be on the shelf and ready to ship within a week or 2, and it should come complete with everything I need to bolt it on and go, including at least a base safe computer program.