Intake meaning the LS3 intake starts to choke around 400HP ?

Thanks roth.
Beer for you too sir.

 

I'm just saying that the stock ls3 intake/throttle body is your limiting factor in this particular setup, especially with a cam change. It will still be strong but that should be your first upgrade in the future. It's all about air in and air out and how fast you can make that happen with a NA engine, a FI setup makes it easier to get the air in part. Keep in mind it's all about a combination of parts and for a budget build with good power your going in a good direction.

 

The LS3 intake isn't going to choke anything.

 

Cool guys.

Heres what its all going in

 

I do feel that using LS3 heads on a 6.0 block could limit your cam choices due to PTV clearance.

Myself, I went with a LQ9 shortblock with 243s ported by AI. Using an SNS2 with headers and a Fast 92mm, I made 452rwhp and 424rwtq. It has a nice flat torque curve and holds peak power from 6200 to 7000rpm.

 

Those are nice numbers. I think if Im over 400 Id be happy - and can decide from there.

PVT clearance meaning a known issue ? Whats specific about the clearance for LS3 versus 243 for example.

 

The intake valve on a ls3 head is 2.165 and a stock ls1 intake valve is 2.00 so with the heads on a 4.00" bore the intake valve will contact the piston sooner on the ls3 than the ls1 with the same size cam. You just need to be more careful with your cam duration with ls3 heads than you do with ls1 heads. With a DD size cam like your talking about you shouldn't have to worry but the cam experts can give you a better idea on just how big you can go. Hope that makes sense. 400 rwhp shouldn't be too much of an issue no matter which route you go but also consider that your running it through a 4l80 auto and a 9" rearend which will sap some power.

 

Thanks.

Did think of another question last night.

All 6.0 ls variants OK...... eg hummer ..... van

How about more modern with VVT etc ..... just have it disabled or ?

Compression and leak down test along with hearing it run enough to make a decent purchase ...... stick to under a hundred and twenty thousand miles ?

 

You'll need to use a gen 4 ECU with the newer engines which will limit you to DBW unless you don't mind not having an idle air controller. There are a few companies that make spectacular VVT camshafts if you go this route.

You could also pick up an LY6, which is a VVT 6.0 that already has L92 heads.

Other than that, not much reason to choose a Gen 4 over a gen 3. They're typically harder to work with and without the DoD or VVT, there aren't many benefits.

 

Joe can you explain that a little ??
I thought both DBW and DBC each had idle air control........
One just goes via cable direct ... other via TAC signal.
But honestly don't really know what it does apart from regulate idle air flow through intake.


The LY6 with L92 heads ...... assuming the flow on the L92 heads is why ?


Lastly - I had mostly been figuring on DBW for tuning as well as I thought they stopped doing DBC post 2003 or something except for some vans .... so chances are OEM setup is DBW ....

So I had thought ...........at basic level

* Get a good <120k mile engine with compression and normal leakdown - ensure grab of ECM and TAC and throttle assembly and MAF/sensors and PCM
* Buy a 4l80e if not OEM with engine - new shift kit for Line Pressure
* Send off harness and ECM for rewire and flash (remove components add 4l80e etc) and clean wiring look assembly.
* Send off PCM for flash to work with 4l80e if required

* Install engine and trans to fit physical
* Install CAM and heads and springs
* Install intake
* Route and hookup wiring harnesses and DBW throttle.
* Configure/Check accessories / codes on ignition on position
* Start

* Post install ... custom driveshaft fit (due to unknown final postion of trans output )
* Post install AC
*Post install custom tune for truck with new heads/cam.

 

The DBW has built in IAC. On DBC, the IAC is a stepper motor that opens/closes to control idle. On almost every gen 4 ECU, the hardware to control a DBC IAC stepper motor is missing, so you'll have to control idle in other ways like adjusting the throttle blade, drilling holes in the blade, etc. If you don't mind mounting an electronic pedal, this isn't a big problem. Also, Gen 4 ECUs don't have a separate TAC module to worry about, they are built into the ECU.

Another problem with the Gen 4 ECU is its inability to control a 4L80e, since the trans controller is no longer part of the ECU in most Gen 4s, its a separate module built into the trans.

The L92 heads and LS3 heads are basically the same casting, with the LS3 having different valves (same size, different material). The LY6 is a VVT 6.0 with these heads and doesn't have the DoD to worry about.

 

But if your using a GEN 4 truck .... you'll have DBW and the GEN 4 ECU. For that matter even on a DBW GEN III truck ...... so really only issue is if you go with a drive by wire setup but want to convert to DBC correct ?? Or am I misunderstanding.
Have a feeling your telling me I may have no option but DBC due to mount of thottle pedal ?

Thought the transmission control was doen via PCM. So no PCM - its integrated in the ECU ... except in GEN4's where its incorporated into the trans itself ?
Little confused on this also as I thought a number of the GEN4 vehicles came with 4l80e ..... like suburban and sierra .... so figured if I targeted one of those combinations Id be fine.

Generally speaking Im going to try and get the Engine and Trans "together" from donor vehicle to ensure better plug and play so to speak.

 

Let me break it down.

Gen 3, you can have DBC or DBW. Some ECUs control both. TAC module is separate.
Worst case, if you want DBC you can just swap to a DBC ECU. It can also control any Gen 3 4L80e. No problems.

Gen 4, The ECU cannot control idle if you swap to cable throttle. The ECU does not have a built-in transmission controller. As far as Gen 4 vehicles, the 4L80e wasn't ever offered in a Gen 4 truck, only vans/service vehicles. Gen 3 continued until 07, so 05-07 4L80e trucks/SUVs are still Gen 3. Your only bet would be to find a Gen 4 4L80e, and do some modifications to the wiring to get it to work.

Here is some info on that:
http://www.trifive.com/forums/showthread.php?t=116617

You can run a gen 4 engine on a Gen 3 ECU with a converter box, but you lose VVT.

 

Thanks Joe !!

Will do more reading around this.
I wasn't planning on using DBC ........ I like the idea of being ableto tune/prgram the thottle. But I've never had to retrofit one and no idea how hard that will be unit l I start it.

Looks like I will be sticking with GENIII for simplicity sake.......

Ill do some more reading over the weekend .... try and fill some gaps. Thanks for the article.

 

Where are you guys getting your engines.
Finding it hard to find a 6.0 under $1500 ........ unless its 200k miles or more.
Florida.

Any good/recommended auto parters that will ship and do compression/leakdown so on ..... sub 120k miles

 

Continuing this.
There's a small part of me that's alsone thinking of non OEM harness/engine/transmission control.

So some questions around this.

If you go carbureted with say a 700r4 tranmission..... what modifications if any needed for Vaccum and cables like TV cable etc.

If go with aftermarket say... fitech/MSD/EZ TCU to avoid compatability problems with ECU and trans.... assume you have to go by DBC. Main reason here is being able to customize everything yourself rather than paying for a $400 tune each time .....

Pros/cons/considerations........

 

Bump it

 

I'm not a big fan of going carb. If you're honestly going to get an LS engine and put a carb and 700r4 on it, you might as well just make it easy on yourself and pick up an older gen 1/2 small block. Far less hassle and aftermarket parts are cheaper. Some of the best things about the LS are the spectacular ignition setup and the factory ECU/fuel injection.

I have even worse words to say about the FITech/MSD or EZ TCU on an LS.
First, the FITech. You pay $1000+ for a system that bolts on like a carb and tunes itself. Sounds like a deal, yes? You can tune the factory ECU for half that, and not have to pay for a new intake manifold. Once you buy HPTuners, you can retune your stock ECU until your head explodes and its not going to cost you anything extra. Not to mention, you still have to spend $350 on an MSD box, which does not tune itself. Actually, since the MAP sensor is built into the FITech, you have a add a 2nd map sensor to the intake if you want to use vacuum advance or boost referenced timing with the MSD. And the MSD box does not tune itself.

Also, there is no communication between the MSD box and FITech. Even worse, no knock sensors. Running too much timing and detonating? No way of knowing. It will not pull timing, it will not add fuel. It will ping until it explodes with no warning. Your MSD box also doesn't receive inputs from the ECT or IAT sensors, so it cannot adjust timing based on engine temps, inlet temps, etc. Basically, by the time you buy a carb intake, FITech setup, MSD box, you're $2000 or so into a system that might be a bit easier to tune than the stock stuff, but is far less optimal.

Then you have things like Microsquirt that works as a full self-tuning standalone with more features than the FITech and MSD have combined, plus a few dozen features a stock ECU couldn't dream of, all for about the same price as HPTuners.


My biggest confusion is that if you're from the 700+ HP diesel community, why is it suddenly such a problem to tune a stock LS computer? Why go out of your way to make things so much more expensive and difficult?

 

Just picked up an LQ4 for $900. Granted, it has a rod knock but I was looking for something that nneeded to be gone thru...

 

My understanding was that for a custom tune/dyno its around $300-400. I have no idea about using the HPTuners but isnt that $50 a credit/tune also each time ? Until I have experience in tuning .... not sure I really want to be playing with ECU tunes outside of some safety limits unless they are built in.

Good points. I assumed the "self tuning" capabilty of the fitech meant it would pull fuel as required ....... but if timing was advanced and depending on throttle position ... then *shrug* .... so ok

Looks too complex - but 1st I have heard of it - just did a quick google

Twin Turbo Cammed 24v PPUMP NO software tuning ........ just fuel, air and timing.

Not trying to make it more expensive or difficult. Just thinking about all the prods and cons to make good decision and not regret it later as I learn more. The carb/fitech appraoch was simply then only good deal I saw on an engine was for a complete standalone engine ..... no harness , ECM etc ........ makes me nervous bolting parts together that didnt go together from factory as you get into issues with things (like you've mentioned) crank reluctor ring variance, ECM transmission software issues (segment swap), VSS output issues (signal and tach), DBW/DBC ....... so on.


I do appreciate the info .....