Marktainium

Looks good! Hope you're feeling better about your' progress... nicely done.

Jimbo1367

Pretty elaborate(sp) And very impressive. Great work.

gofastwclass

iTrader: (2)

Interesting trans crossmember. If it could go in and out as one piece I would have rather welded the center solid instead of using bolts. Just my preference but it looks great.

Nice build.

nerveink

iTrader: (2)

you da man!!!!

frojoe

iTrader: (10)

I totally agree... but in order to be able to lift it up and back as one piece and not interfere with the floor, it'd have to be very flat and that would provide very little exhaust clearance... not the look I was going for...

MillsMotorvation

I think i read the whole thread, and you do great work, but i didnt see detail info on how you got the engine wired, ECM, and harness work. Im about to start on a 81TTA, and i have a 6.0 LQ4, ECM, hareness, and have no idea of what i need to do to get it running. I see how the fuel setup is, but no idea how the ECM, should be run. I know it late in the thread.

frojoe

iTrader: (10)

I contacted John Spears of Speartech and for $800 I got a complete plug-and-play ready to go wiring harness. The minimum it required to run the engine was a constant 12+ battery, ignition hot to crank the starter, and a ground. Optional were the cruise control, fuel pump relay turn-on, fan control turn-on, tach output, A/C, and a couple other things too.

I went this way because considering it's all new high-quality automotive grade wiring with OEM connectors, completely simplified for ease of installation, and guarunteed to just plug in and work, it's a pretty good price. Harness length was 4 or 5ft I think which was plenty... probably even enough to put the ECM under a seat. Not to mention John was excellent at answering questions pertaining to my harness as well as lots of other LQ4 EFI questions both before & after the purchase.

I know painless offers a stand-alone harness for a good price, but the couple years ago I looked into it, it seemed like it still needed a bit of modding. Not sure if they've refined options for it. Also I'm pretty out of the loop on any other new manufacturers offering nice simple stand-alone harnesses.

Does this help out? Feel free to ask any more questions and I'll try to help as much as I can!

MillsMotorvation

Thanks alot, forgive me for being so lost. I also wanted to know did he flash your EMC, and im wanting to run a turbo will the EMC know that, and what is this 3bar- 2bar thing is that got to do with boost?

MillsMotorvation

Another thing, i see on the truck intake it has what seem to be the return line for the fuel near the FPR, will i still need to get that Corvett regulator?

frojoe

iTrader: (10)

Hmm what year is your truck motor? Some came with the FPR on the rail with a return (like yours if your reply was describing your own intake) or a returnless system, like mine. I'm not sure what pressure the truck FPR is set too, presumably something similar to the Corvette one, but if you're planning on boosting, I would HIGHLYsuggest ditching the truck FPR for something that can flow higher and/or have some adjustability. Depending on your planned power, the Corvette FPR might even be a bit restrictive with 3/8" in/out and a 5/16" return. If you decided to not use the on-the-rail truck FPR, I'd suggest locating a newer truck cross-over tube so you can safely just feed it one pressure line, as opposed to modifying/plugging the one you have.

How high are you planning on boosting? I'm not positive on this, but I think 3bar is aftermarket territory, and the Cobalt SS one is 2-bar... that's what I plan on doing.

Also, it's nice to have an adjustable one so you can nail the pressure you desire, or even have the pressure ramp up with boost... Some people like to get big injectors with no change in fuel pressure and just have all the fuel tables modified on the PCM for the boosted setup, but if you have large enough injectors to satisfy high rpm/boost, the injectors will have a (slightly) harder time at lower rpm & idle because of their decreased spray times (injector resolution). Lots of people swear that 60+lb/hr injectors can be tuned to have really good idle characteristics, but to me this seems like creating more work than necessary.

I'm planning to use an LS2 tune along with the LS2 42lb/hr injectors (got mine from an LS7) and a ramping adjustable FPR that increases fuel pressure 1:1 with the increase in boost. I'm planning a MAX of 12psi for now (hopefully I don't get greedy/need to crank it for a while ), and so from idle -> full boost the fuel pressure will ramp 58psi -> 70psi... This was pretty well confirmed by multiple common fuel/boost formulae as well as (too much) time searching Google.

This seems like the easier way to me, starting with a stock(ish) setup and turning up the wick to pump out more HP, as opposed to just tuning larger injectors and having to start from scratch. This will be a good baseline to start driving the car a bit, but of course to squeeze more power out and make it most efficient, a unique tune on the dyno will be required pretty soon after.

Also, not sure what is going to go on with the MAF, think I'll keep it on there since I'm not planning on doing a speed-density tune yet, leave that for when the I want to squeeze more power out of the car. Hopefully the MAF doesn't get pegged with the 7-8psi I plan on starting out with.

OK, it's Saturday night, I need to go drinking... cheers!

MillsMotorvation

Thinking of running around 15psi, I think the engine came out of a Express Van (2002) It has a return line on the fuel rail, and what looks like a FPR. So i need to know what when i get the PCM tuned? As far as injectors not sure what kind i have, but will the same injector out of a Vett fit a truck intake? Also do i need to get PCM tune for larger injector? I have a 87 Grandnational, and i run Alky on it, and plan to run it with this setup, i can use fairly small injector, and let the Alky supply xtra fuel, and higher octane.

frojoe

iTrader: (10)

Hmm... I believe that the LQ4 only started being used in teh Express van in 2003... 2002 would have had the 5.7L smallblock, is there any way you can confirm where it came from?

Regardless, I think LQ4's come stock with 28 or 30 lb/hr injectors... but not positive on that. Even if you ramp the hell out of the fuel pressure, I'm pretty sure you won't get near enough fuel to supply 15psi. 15psi would be 3bar territory I'm pretty sure, plus that would give you room to grow boost-wise ( !!). Siunce you plan on doing alchohol injection then, that'll help, but I would still recommend a larger injector.

When you get larger injectors, if you were to keep stock settings, you'd have to decrease the injector spray time to let less volume, but since you are now boosting and need more fuel anyways, the only way you can program the fuel tables to spray the proper amount is by tuning/dyno time.

The truck intake is so tall that most other injectors are short enough (in comparison to stock truck injectors) to need a spacer in order to mate with the stock fuel rails/crossover tube on a stock truck intake.

However, I'm really no expert on this so it's best to venture over to the Forced Induction or Fueling Injection sub-forums...

MillsMotorvation

OK, thanks. I know alot about Grandnationals, totally lost in this LS stuff. Its a learning curve. Im just trying to avoid doing thing twice, and spending cash on things i dont need. I just got done modifying the stock harness waiting on fuse block, and relays. You guy's make it look easy, i dont know for sure what type truck the engine came from, how important is that to my build?

Jimbo1367

FroJoe,
Great work and keep dem pics coming.

MillsMotorvation

I know ive been asking alot of ???, I slowed down, and looked at your parts list, and that was the best help ever!!! I dint see where you got a new fuel rail, is that the stock one for a 2005? The one on my engine has a return line, and what looks like a FPR, anyway thanks!

350SS

iTrader: (38)

Jimbo1367

updates.........???

MillsMotorvation

It's me again! Ive been doing my own harness(wish me luck), anyway at first you were going to use a 350trans. How, or what did you use to get the VSS to work? I know the cable will work for my factory speed-O, but what can i use to give PCM the right signal?

Marktainium

I think you only need the VSS if you are a) using the embedded ecm cruise control, or b) you are using an electronic speedometer. If you are using a th350 and factory gauges you just run the original cable and thats it. No VSS needed.
If you are running a VSS equiped transmission, say a 4L60 or a T56, then to run you're stock guages you need to get a speedo drive adapter. This is a device that converts the electronic signal into a mechanical drive. Here's a link...http://www.atrol.com/cablex.htm

MillsMotorvation

OK! Thats great, i was thinking the PCM needed that VSS for the engine to run right.