Hey all,
In the midst of swapping an LS3 into my C5...long story short, dropped a lifter, pieces of metal, cost to replace with LS3 washes with cost to rebuild LS6. So, lots of info on this topic and I've been searching extensively, think I've got most everything covered/accounted for, but just wanted to ask the forum for a quick "self check" to make sure I'm not missing some important detail. Going to be ordering parts this week and then new motor goes in. (Yippee!!)

Okay, so primary issues - going to make a list of the main things and a couple questions I have, please feel free to jump on any of them and correct if I'm off. Appreciate IMMENSELY any help!

1) Crank Trigger Issue
- Going to pull the crank and install a 24X reluctor wheel. I track the car (primarily) and just can't have it flaking out on track.
2) Knock Sensors
- Re-tap LS3 Knock sensor holes and install LS6 Knock sensors - knock sensor harness extension
3) Cam Trigger Issue
- Replacing cam (Sloppy Stage 3 - should make some good HP and insure I'm not beating the hell out of my valvetrain ([ongevity/reliability considerations] - I expect I'll redline in the 7K range and it will get used)
4) Injectors
- I've seen a couple options for this, on this forums talked about EV1 (Jetronic) to EV6/EV14 adapters (set of 8). On LS1 Tech I saw an option for a single Katech (KAT-A4758) harness. I prefer the single option and Katech does good work - I see reference to that harness, but not seeing it on Katech's site. Does anyone know if they still make it or do I need to go the other route?
5) MAP Sensor
- Think I'll stick with the LS3 Bosch sensor and use Katech MAP adapter (KAT-5185) and their MAP extension (KAT-4751).
6) Throttle Body
- Here's the biggest question I have, I've seen it stated the LS3 TB won't work with C5 ECU so option is go to LS2 TB and use a harness (Racetronix). On the LS1 Tech they mentioned a Katech adapter (KAT-4752) and left it at that. Does the Katech harness convert so an LS3 TB will work with C5 ECU? I'm into this whole thing for a good bit, so if I don't have to get another TB that helps mitigate costs. It already has a LSXR 102 Intake on it and not entirely sure if the LS3 or LS2 TB is the better option. Any thoughts/advise welcome on that.
7) Clutch
- Stage 4 clutch going in, rated to 673hp so should be good there.
8) Cam/OP sensors
- putting LS6 Cam/OP sensor onto the LS3
9) Canister Purge Solenoid
- Transfer from LS6 to LS3
10) Oilpan
- Do I have to bring the Batwing over or can I use the LS3 pan? If I do have to bring the Batwing I've seen it mentioned that the Oil Pickup bore is bigger on the LS3 and it was mentioned to put/use a "Red O-Ring"...any more specifics on what that is or where to get? Is it just an appropriately sized O Ring? Any clarity on that would be helpful also.

That is about the extent of the major items I'm aware of. Figured it would be easier/more succinct to condense into a new thread and ask the question(s) vs. resurrecting a bunch of old ones. Maybe will be helpful to someone else who is doing this in this timeframe also vs. scouring through a bunch of old threads also.

Appreciate any input/guidance/suggestions...going to post in the AutoCross/Roadracing forum also for visibility.

Thanks!!!

 

I fear I have no knowledge or experience to contribute, but your path sounds exactly in line with what I envision at some point in the future, so will be paying rapt attention to your progress!

 

Good choice on the 24x wheel. Be sure to use the LS6 crank sensor.

For the injectors, just buy the proper pigtails. Cut the stock ones off right at the connectors, the wires are short. Solder and heat shrink the new ones in place.

For the knock sensors, I used the spare motor mount bosses available. Sensor screws right in. I used the LS3 sensor pads for grounds. Batt and frame.
Be aware that although in place, they don’t function correctly as the sensitivity and sequencing are wrong for the LS6 ecu. They do keep the check engine light off.

LS2 silver blade TB is the easiest. One tune change, and the adapter harness required.

Cam sensor just needs an adapter/extension harness.
Ditto for the MAP.

I used the LS3 pan. It’s wonderful for header and starter installation. But, the oil control sucks. I had to overfill by 2 quarts to keep the oil pressure happy when launching at the dragstrip. Since you will be carving corners, the batwing will be far superior. Bolt your bellhousing to the block when installing the pan so you get the pan aligned properly.

The pass side frame stand for the mount will run into the third mount boss for the AC compressor. So you can either modify the stand (it’s easy) or grind that extra boss off the block.

And of course you will need a tune. Which is also quite easy. At least it was for me as I’m a tuner.

Ron

 

You can use an ls3 tb, just need to adjust max opening in the tune. There are a few threads here if you search for them.

 

Saw those, or a video...can't remember off top of head. I think it was like 96.8% or something like that. I'll look it up - thanks!!

 

interested in hearing the final result.

quick question since you were going ls3 engine and possible TB, why not the LS3 ECU ? kept it all 58x and ls3-ed up?

Lyle at C&S has been talking about the throttle response units ( red light bandit etc) which work with the newer ECUs but not the C5.

good luck with the build -

 

The other systems in the C5 don’t speak the same language as the LS3 ECU

 

gas and brake … what other systems do u need ?

 

Yeah, converting like 2-3 harness attachments seems like a lot less effort/fail points than trying to adapt all the other stuff on the car. The electronics, while neat and helpful, are also an absolute nightmare when they fail. GM is pretty good with their engineering so I'm attempting to alter as few line items as I can.

 

I converted my 02 exactly as you are planning. I used the racetronix cam, tb, knock sensor and map harness. The knock sensors/harness needs a heat shield if running longtubes and they still might melt, particularly the drivers side. There is just not much room there. I used the injector adapters and had no issues, your mileage may vary. Other than resoldering some of the racetronix adapters, no issues. I checked the harnesses for continuity and ohmed them before install.
If you’re going to change the reluctor, replace with a billet reluctor especially if it will see 7k routinely. I agree the reluctor change is the safe/reliable way to swap. Jmo.
I used the ls2 tb when I did the swap because there was no consensus on the ls3. Some said it worked, others had nothing but issues. Seems to be resolved now.
I ran the batwing oil pan, just seemed superior for my mixed use.

That setup had 20-25k miles of street, drag, etc over a few years. I have converted it back to an ls6 car and was glad I didn’t chop any harness.

 

Great feedback all, so appreciated. Latest question, and I am admittedly behind where I wanted to be but that is another story, anyway: I have a coil pack that got damaged in transit of the motor. So the question I'm posing to myself (and now everyone) is should I just replace the one damaged one or all of them? Not sure what the lifespan is on coil packs and/or giving the motor a little extra (i.e. Cam, 102mm Intake/TB, tune, etc) do I need to adjust the coils to match? Looking to be about 500-525'ish whp so per flow calculators I am good on injectors at roughly 85% duty cycle. Just don't know about the coil packs...

The second side of this question is: I have a full and functional set of coils on the LS6. Could I just swap those onto the LS3? Then I don't need to mess with connectors etc, but not sure if the voltage on the LS6 coils is sufficient for and LS3...especially if the LS3 is tweaked a little. If I need to just replace with LS3 coils so be it...not excited about it, but I want to do it right and not have to come back in the near future and correct something silly I could have bypassed now.

As always, THANK YOU!!

 

just a quick ls1tech / c-forum search - shows there are some differences - unfortunately I don't have much experience with this.
As for the one that is damaged - I would probably just replace the one. With all of you planned upgrades - keep it simple when you can.

My claw - wrench set has arrived today - so I will be installing the BTR stage 3 cam soon in '02 z06.

Hope your swap goes well -

 

Okay...this is probably a dumb question, but: can you put an LS1 (EV1) injector in an LS3 (EV6)? Is it just the connector that is different or is the actual injector where it plugs in different?

 

I believe they make adaptors to do just that with the injectors, I personally would not use them for fear of leaking, 60 psi gasoline is not something I want spraying under my hood.
i was using the ls6 coils on my setup and had no issue, it made 500 rwhp. So right in the same range. That was with stock injectors and intake with a hotwired fuel pump.

 

Awesome...I'll most likely just use the adaptors, just kind of asking the question. Great to hear the LS6 coil pack works though!

 

I should clarify...the adaptor for the plug and just use LS3 injectors.

 

Yes, I definitely misunderstood. Adapters with the stock 42lb injectors is how I had mine wired up. They were right under 80 dc on the dyno iirc.

 

You were probably interpreting correctly the initial question...I initially inquired about physically sticking an EV1 injector into an EV6 slot. When I responded to clarify I intended to mean I would probably just go the route of the connector adaptor as it is a known/tried method. I was originally inquiring about physically putting, for lack of a better description, the old LS6 injectors on the LS3 motor solely to not have to mess with the harness adaptors or a pigtail swap.

Have no idea if they would fit/work (as mentioned originally - probably a dumb question), but I agree the biggest issue would be they leak and you are absolutely correct in that 60psi gas spurting in the engine compartment at speed would a bad thing! LOL

 

I was working and browsing the forums, read it quickly and assumed I misread. I think you can go the other way, ie ls3 injector in a ls1 intake but iirc ls1/6 injectors are longer than ls3. I think there were some rails with spacers and adaptors you could use at some point. It just all seemed a bit hokey imo. There’s adaptors for about everything in ls world, caveat emptor for sure.Ict billet carries a bunch of that stuff and has a pretty good guide/schematic. I’d link it but I believe it’s frowned upon. It’s in their ls swap guide stuff.

 

LS3 injectors are short. Just use the electrical adapters. Or solder in new pigtails like I mentioned above.

LS3 coils need different dwell data in the tune. Much easier to just use the LS1 coils. I think the coil packs will bolt on to the LS3 valve covers. If not, just use the LS1 covers.