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LSx standalone wiring harness question

2turbotoys

2turbotoys

Salaminizer
Joined
Nov 13, 2007
Location
Reading pa
So I had a bit of a misunderstanding about what a standalone wiring harness was, I pictured a harness for a standalone aftermarket ECU like Motec or FAST EFI, but what it really means is standalone from the truck so the engine can be used without whatever sensors are unique to the truck.

So I'm having the harness/ecu modified to be the second version of standalone. My question is about where to make the harness exit from the engine. I am planning on a twin turbo setup so this may be pretty important.

Option A: Currently it will exit on the front passenger side, putting the ECU behind the headlight bucket

Option B: Make it exit at the rear of the engine, and run the harness through the firewall into the car.

What did you guys do? Any thoughts welcome
 
I would put it in the car if you're doing twin turbskis cause underhood space is going to be at a premium at that point anyway. Who's gonna tune it for ya?
 
That kinda what I'm leaning towards also. The guys I got the engine from (LSX4U.com) tuned it for the cam and standalone stuff, its at about 450 hp right now, N/A. When the turbos go in I will probably switch to a FAST self learning system and my buddies shop where I am installing it will tune that. They are pretty familiar with the FAST stuff and turbo motors, not so much the LSx but that's not a big deal
 
yeah the holley stuff is very highly regarded in the circles I associate with (although, no one local has one so I haven't had the opportunity yet... may sell the megasquirt setup off of my green car and get one tho, see what life on that side is like..)
 
I will still always use megasquirt on my personal stuff but have been using a bunch of holley stuff with a friends car and work stuff. It just plain works and is geared toward the typical turbo v8 build.
 
Holley makes the FAST EFI...I have a tuned ecu to get it going N/A, and have a huge amount of work to do, so holding off on that for a bit. I don't have to tell you guys how much there is to do, for example the only stock suspension pieces are the tie rod kit and ball joints..
 
55superbeetle said:
I will still always use megasquirt on my personal stuff but have been using a bunch of holley stuff with a friends car and work stuff. It just plain works and is geared toward the typical turbo v8 build.
Click to expand...

I like my pro, and I think they finally figured out the ultimate, but I'd like to broaden my horizons a bit. I took an hptuners class two weekends ago that was really eye opening (James Short taught the class), and several really fast folks speak highly of the holley system.

Another one that's starting to gain traction (no pun intended) is maxxecu, and one of our own is a dealer for it to boot.
 
Holley and FAST are completely different ecu's, and I don't think they are connected. If you have a cable driven throttle body and don't need to control a transmission the Holley HP will get it done. If you're really trying to make big power and go fast I guarantee you that relying on somebody else to make changes or figure out an issue will get old very fast. That's the only reason I suggested the holley. Everybody knows the stock ls computers are very capable but with it being pretty dang easy to make 800-1000 hp these days you will eventually want some way to build boost, some way to control boost, and some way to ramp power in, whether time, or speed based. That's when the aftermarket ecu's start to make more sense to me. Just trying to give advice to save you time and money in the long run.


linuxman51 said:
I like my pro, and I think they finally figured out the ultimate, but I'd like to broaden my horizons a bit. I took an hptuners class two weekends ago that was really eye opening (James Short taught the class), and several really fast folks speak highly of the holley system.

Another one that's starting to gain traction (no pun intended) is maxxecu, and one of our own is a dealer for it to boot.
Click to expand...

Just installed an evo on a big block chevy, so far so good. I would love to go to one of scott clarks classes as just listening to his podcasts has helped me a ton, definitely on my list of things to do. I've used hp tuners just as a repair tool quite a bit, looking at the tuning side of it on the real new stuff scared me enough to not even try to make room in my brain for that.
 
55superbeetle said:
Holley and FAST are completely different ecu's, and I don't think they are connected. If you have a cable driven throttle body and don't need to control a transmission the Holley HP will get it done. If you're really trying to make big power and go fast I guarantee you that relying on somebody else to make changes or figure out an issue will get old very fast. That's the only reason I suggested the holley. Everybody knows the stock ls computers are very capable but with it being pretty dang easy to make 800-1000 hp these days you will eventually want some way to build boost, some way to control boost, and some way to ramp power in, whether time, or speed based. That's when the aftermarket ecu's start to make more sense to me. Just trying to give advice to save you time and money in the long run.
Click to expand...

^ this, all of this.. it's not a matter of whether or not the ecu can hit the number, it's being able to put the number to use.



Just installed an evo on a big block chevy, so far so good. I would love to go to one of scott clarks classes as just listening to his podcasts has helped me a ton, definitely on my list of things to do. I've used hp tuners just as a repair tool quite a bit, looking at the tuning side of it on the real new stuff scared me enough to not even try to make room in my brain for that.
Click to expand...

scott's a trip, he carries on exactly how you'd expect him to based on the podcast, in person. (which is to say, the same) another somewhat unspoken perk of his classes is the networking. You're not in a class with a bunch of bottom level bitches, there were several seriously smart guys in the class I took, and a couple noobs (who were just about lost right out of the gate, having no background in any kind of efi tuning), but mostly it was folks already in the industry looking to improve techniques and/or add skillsets.
 
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Gotcha, that makes sense. I already have the stock ecu tuned and the harness is paid for so thats the cheapest thing to do now, I should have asked this question before...
I have the electronic throttle body right now, the car has a manual transmission
 
Two things to keep on the harness are the trans speed sensor and fuel composition sensor for E85. Some of the custom harnesses skip these items which the ECU needs.
 
2turbotoys said:
I'm not going to run E85, still needs that?
Why does it need the trans speed sensor?
Click to expand...

E85 is glorious, you should consider it. Especially for Turbo as the octane rating is higher than gas so you can run more timing. Sloppy Mechanics IRRC has some good information on dyno back to back. Other may want to add in here for the E85 debate.

E85 is now available locally in VA at the normal pump as yellow Flex Fuel.

The speed sensor is for using the stock GM ECU, for some reason the ECU needs to know that the car is moving. The accuracy of the sensor does not matter just stopped vs moving. I suspect for idle air control.

If you go straight Holley, these items probably do not matter. But I bet Holley has a E85 capability...?
 
I can't get E85 anywhere near me, thats why I'm not really considering it. Its a 45 minute drive to the closest place. I know its good for power though.

I'll ask them about the speed sensor thing.
 
Pillow said:
E85 is glorious, you should consider it. Especially for Turbo as the octane rating is higher than gas so you can run more timing. Sloppy Mechanics IRRC has some good information on dyno back to back. Other may want to add in here for the E85 debate.

E85 is now available locally in VA at the normal pump as yellow Flex Fuel.

The speed sensor is for using the stock GM ECU, for some reason the ECU needs to know that the car is moving. The accuracy of the sensor does not matter just stopped vs moving. I suspect for idle air control.

If you go straight Holley, these items probably do not matter. But I bet Holley has a E85 capability...?
Click to expand...

holley typically has it's own harness anyway, so it's not really that big of a deal
 
I've been running a goldbox ms3x in my car for almost 2 years, I love it. Never had any issues with it. For the price it's pretty hard to beat. But if your going to have someone else tune your car, ask them what they prefer
 
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