: Looking for info on the LC3 blower setup



gettinblown
01-29-13, 02:22 PM
Hey gang, hope I'm putting this in the right spot. First post here, I'm not a caddy owner, but I will soon own the blower setup from an LC3, for installation on my BMW 740i sport :lildevil:

103079

I got the idea from an old post over on bimmerforums, a couple of west-coast guys with a shop dropped one on their 540 (same engine, smaller chassis):

103080

So I know it can be done, but they seem to have disappeared, while my desire has only grown :yup:

I wanted to ask y'all some questions while spelling out my intentions, and hopefully get some feedback:

I've enlisted a machinist to CNC some aluminum adapter plates using the BMW and GM intake mani gaskets as guides, to handle the lion's share of the mounting issue. I'm purchasing one of those $900 new blowers off Ebay and he's get a spare engine to use to mock it/fit it/test etc, so I think that part of the project should be relatively easy. If we need to machine a new pulley we can do that, and the longer belt is just a Napa visit away.

I so far plan on using the GM fuel rail and injectors, while mating my OE fuel line to it. Thought being that those injectors are larger than mine for more fuel delivery, and the rail and injectors are ready to mate to the blower, so no spacers or o-ring hassles to deal with. All I've got to do is confirm their impedance and purchase pigtails to solder into my factory harness so they can be plugged in. At this stage in the game we're (there are other guys following my progress) ok with the standard injectors, no larger ones are sought yet, though I bet some of y'all have already ;) I'm hoping that my MAF and O2's can "pull" enough duty cycle from the larger injectors when not in boost, to still allow the car to drive and get MPG's and whatever, tho it should go without saying after this is all up and running, dyno tune time is a must.

We're either going to mate our TPS to the GM TB or just mate the entire BMW TB to the GM blower, to address that issue.

The remote intercooler pump and heat exchanger, I plan on purchasing most of those pieces and setting that system up on my car, as the factory cooling system's ~230F operating temp:suspect: makes tying into it outright dangerous. If the car ran at 160-180F I'd consider it in the short-term just to work out the bugs, but I won't run non-intercooled nor will I run 230F coolant through the "cooler" either, for obvious reasons.

So where do I (and future followers) go to purchase the OE components we'll need? I've read up on the upgraded intercooler pump, even, but again, for my modest goals, the stock injectors/rail/pigtails and intercooler with pump and hoses will suffice. Have any of y'all upgraded beyond the stock components, and have the old stuff laying around? I'm shopping :D

Sorry for the long post, but I am going to follow through with this, and am fully aware of the dangers, and have plenty of past experience with FI, blah blah blah, so I'm looking for educational sincere discussion. Thanks guys,

Chuck

gettinblown
02-04-13, 10:14 AM
Ok.... I've addressed all of my questions above, but now I've got just a few more:

Where can I read up on what all the ports on the supercharger do? Which ones gives a pressure outlet, which ones, if any, need vacuum, etc..... What's the big actuator do on the front? It looks like it's tied into the TB somehow? I see a sending unit on the front, what does it read? Just point me in a direction guys, I'm not looking to be spoon fed ;-)

todrules
02-04-13, 03:47 PM
I don't know much about the LC3 supercharger since I've only had mine for a year or so. I do know the M62 motor like the back of my hand. I had 3 e39's previously, the liquid cooled alternator still makes me say WTF?

boomys10
02-04-13, 04:21 PM
the actuator is the manual boost bypass. it will bleed boost off once a certain vaccuum is hit and wont allow the blower to go over 12psi.

gettinblown
02-04-13, 04:39 PM
I don't know much about the LC3 supercharger since I've only had mine for a year or so. I do know the M62 motor like the back of my hand. I had 3 e39's previously, the liquid cooled alternator still makes me say WTF?

Yeah lol you n me both, mine went out just a couple months after I bought it, couldn't believe I had to fight with the cooling system to replace it, but w/e....


the actuator is the manual boost bypass. it will bleed boost off once a certain vaccuum is hit and wont allow the blower to go over 12psi.

Did you mean "boost/pressure"? Thanks for the reply!

boomys10
02-04-13, 07:18 PM
it works off vaccuum. so both answers are correct. i dont know how it would work with your setup, but with ours when the boost gets to a certain level the vaccuum is increased which opens the solenoid and bleeds the xtra off.

TimmyC
02-05-13, 01:06 AM
Ok.... I've addressed all of my questions above, but now I've got just a few more:

Where can I read up on what all the ports on the supercharger do? Which ones gives a pressure outlet, which ones, if any, need vacuum, etc..... What's the big actuator do on the front? It looks like it's tied into the TB somehow? I see a sending unit on the front, what does it read? Just point me in a direction guys, I'm not looking to be spoon fed ;-)

There is one pressure port after the intercooler lid, one before and a couple vacuum only ports on the back for brakes and the bypass valve actuator. That's the black thing on the front. It is connected to the bypass valve via a cable underneath. It opens the bypass valve so the supercharger is not creating boost during cruising. When vacuum decreases, i.e. you open the throttle, the bypass valve actuator closes the bypass valve and the blower creates boost. You don't have to do anything to make this work. It's all contained on the supercharger.

The STS-V has a boost pressure hose plumbed into the other port on the bypass valve actuator with a solenoid inline that allows the computer to open the bypass valve even when in boost. It does this to limit boost in certain situations. I've had mine pulleyed to 17.5 psi without this occurring but other people report issues with it. You don't need to worry about that because you won't be using that feature.

gettinblown
02-05-13, 09:56 AM
Thanks Tim, for your time and the reply, I appreciate it. If I could just bother you a little more, I did manage to access an AllData server and printed as much about the blower as I could, including some pictures, but unfortunately, the diagram isn't "to scale", so I can't exactly discern what port does what. I know now that the sensor on front is simply an IAT2 sensor feeding back data to the ECM, which as you noted we (and we're perfectly ok with), won't be using, so no worries there.

If you wouldn't mind taking a look at this pic:

http://i.ebayimg.com/t/Supercharger-for-Northstar-4-4L-DOHC-LC3-V8-2006-09-Cadillac-STS-V-and-XLR-V-/00/s/MTIwMFgxNjAw/$(KGrHqYOKjYE6lLVnWq2BOpr++!Yl!~~60_57.JPG

and tell me exactly what (from L-R) ports 1,3, and 4 do? I'd really appreciate it. Also, there appears to be a port on the TPS itself? Is that crucial to anything? We'll be using our OEM TB and TPS, so if it's not critical to SC operation, that's fine.

Is the larger tube running off the bottom of the plenum immediately behind the throttle plate, and wrapping around the side of the unit, dead-ending on the side in what looks to be a quick-connect style fitting, the primary boost pressure signal? It's pictured here:

http://i.ebayimg.com/t/Supercharger-for-Northstar-4-4L-DOHC-LC3-V8-2006-09-Cadillac-STS-V-and-XLR-V-/00/s/MTIwMFgxNjAw/$(KGrHqEOKjkE6WWuFh-+BOps!MPz1Q~~60_57.JPG

Lastly, the port directly below the IAT2 sensor, on the front of the unit, what's its purpose? If I'm seeing the pictures correctly, my auction blower will include the boost control solenoid, tho I won't need it/can't use it, so I imagine there's some "extras" that are confusing me at the moment.....

Sorry for the links, I can't figure out how to load images :annoyed:

carter's_sts
02-05-13, 11:13 AM
Sorry to jump in on this, but this is great info. I'm wondering if the computer controlling the bypass valve is why I had a lack of power one time.

http://www.cadillacforums.com/forums/cadillac-sts-v-series-forum/277545-weird-lack-power-today.html

Do you know the reasons why the computer would open the bypass valve?

Thanks.




The STS-V has a boost pressure hose plumbed into the other port on the bypass valve actuator with a solenoid inline that allows the computer to open the bypass valve even when in boost. It does this to limit boost in certain situations. I've had mine pulleyed to 17.5 psi without this occurring but other people report issues with it. You don't need to worry about that because you won't be using that feature.

gettinblown
02-05-13, 11:51 AM
Sorry to jump in on this, but this is great info. I'm wondering if the computer controlling the bypass valve is why I had a lack of power one time.

http://www.cadillacforums.com/forums/cadillac-sts-v-series-forum/277545-weird-lack-power-today.html

Do you know the reasons why the computer would open the bypass valve?

Thanks.

According to the pages I printed off AllData, there are several reasons

Begin reading at "Operation" almost at the bottom of the page:

103455
103456

Hope that helps, sorry for the rotate, couldn't get em to upload normally

TimmyC
02-05-13, 01:58 PM
Thanks Tim, for your time and the reply, I appreciate it. If I could just bother you a little more, I did manage to access an AllData server and printed as much about the blower as I could, including some pictures, but unfortunately, the diagram isn't "to scale", so I can't exactly discern what port does what. I know now that the sensor on front is simply an IAT2 sensor feeding back data to the ECM, which as you noted we (and we're perfectly ok with), won't be using, so no worries there.

If you wouldn't mind taking a look at this pic:

http://i.ebayimg.com/t/Supercharger-for-Northstar-4-4L-DOHC-LC3-V8-2006-09-Cadillac-STS-V-and-XLR-V-/00/s/MTIwMFgxNjAw/$(KGrHqYOKjYE6lLVnWq2BOpr++!Yl!~~60_57.JPG

and tell me exactly what (from L-R) ports 1,3, and 4 do? I'd really appreciate it. Also, there appears to be a port on the TPS itself? Is that crucial to anything? We'll be using our OEM TB and TPS, so if it's not critical to SC operation, that's fine.

Is the larger tube running off the bottom of the plenum immediately behind the throttle plate, and wrapping around the side of the unit, dead-ending on the side in what looks to be a quick-connect style fitting, the primary boost pressure signal? It's pictured here:

http://i.ebayimg.com/t/Supercharger-for-Northstar-4-4L-DOHC-LC3-V8-2006-09-Cadillac-STS-V-and-XLR-V-/00/s/MTIwMFgxNjAw/$(KGrHqEOKjkE6WWuFh-+BOps!MPz1Q~~60_57.JPG

Lastly, the port directly below the IAT2 sensor, on the front of the unit, what's its purpose? If I'm seeing the pictures correctly, my auction blower will include the boost control solenoid, tho I won't need it/can't use it, so I imagine there's some "extras" that are confusing me at the moment.....

Sorry for the links, I can't figure out how to load images :annoyed:

1 and 3 are the vacuum only ports I talked about before. That line goes to the bypass actuator.

4 is the evap solenoid for emmisions. Remove that and plug the hole.

The hose that looks like it is going to the throttle body goes to the valve cover; it's a breather line.

The port on the front under the air temp sensor is the manifold boost/vacuum port for the MAP sensor.

gettinblown
02-05-13, 02:53 PM
Thanks again Timmy!

carter's_sts
02-06-13, 12:37 AM
Thanks for the great info.

I wonder what the heck "When drivetrain abuse is detected" means?


According to the pages I printed off AllData, there are several reasons

gettinblown
08-01-13, 10:17 AM
Dragging this back to the front, we've been slowly making progress on this project, not unexpected, there's always some delays to deal with, but we're back in the saddle again, and I've got an idea I'd like some feedback on pls:

Timmy/others, the thought is to offer an option on this blower package that significantly lowers the boost pressure so that the intercooler can basically be ignored for the end users initial install, then down the road at the time of their choosing, they can add on the heat exchanger/pump/etc, fill the system with coolant, and up the boost.

I went back of course, to my turbo days and electronic boost controllers, but I think I'm backwards: EBCs raise boost pressure by restricting the boost signal to the wastegate actuator, but the Caddy's OEM boost control solenoid appears to be able to limit or disable boost by opening up the boost signal to the bypass actuator? So I take it it's normally closed, and actually opens to limit the maximum boost pressure (or even disable boost altogether)?

Now, I know we're not going to be using the OEM boost control solenoid, but the actuator has to stay just for the blower's operation. So, aside from custom pulleys, how do we lower the boost pressure output on that factory setup?

CMNTMXR57
08-01-13, 12:08 PM
Can't you command the BOV in the tune to open under certain criteria to help bleed pressure some. I know our PCM's have a heat provision to open the valve and bleed pressure (260* I believe), but not sure if there are other parameters that can also trigger a pressure bleed.

gettinblown
08-01-13, 03:02 PM
We won't be using the factory boost control solenoid in this setup, but its operation gives me, I think, the answers I was looking for.

We're going to be using the blower as purely a mechanical assembly, so in my mind, much like your everyday snail shell Vortec unit, the pulley size would determine maximum boost pressure, or approx. 12 psi, way too high for our initial goals. We want to be able to lower the boost pressure, just like the OE solenoid would, as you mentioned, during certain conditions. I'm pretty sure, then, that we can use an aftermarket electronic boost controller to limit the boost signal that the actuator sees. I don't know why GM chose to bleed off the boost signal, but the operation should be the same. If we lower the boost signal making it back to the actuator either by bleeding off or restricting, we should be able to limit the maximum boost that the assembly makes.

Anyone see any problem with that thinking? Takes a HUGE step out of the process, not having to worry about machining and replacing the pulley. It's doubtful anyone of us would ever want to run more than 12 psi, but that's where the changing of the pulleys would come in, correct?

TimmyC
08-01-13, 08:53 PM
We won't be using the factory boost control solenoid in this setup, but its operation gives me, I think, the answers I was looking for.

We're going to be using the blower as purely a mechanical assembly, so in my mind, much like your everyday snail shell Vortec unit, the pulley size would determine maximum boost pressure, or approx. 12 psi, way too high for our initial goals. We want to be able to lower the boost pressure, just like the OE solenoid would, as you mentioned, during certain conditions. I'm pretty sure, then, that we can use an aftermarket electronic boost controller to limit the boost signal that the actuator sees. I don't know why GM chose to bleed off the boost signal, but the operation should be the same. If we lower the boost signal making it back to the actuator either by bleeding off or restricting, we should be able to limit the maximum boost that the assembly makes.

Anyone see any problem with that thinking? Takes a HUGE step out of the process, not having to worry about machining and replacing the pulley. It's doubtful anyone of us would ever want to run more than 12 psi, but that's where the changing of the pulleys would come in, correct?

Installing a heat exchanger and pump is much easier than trying to figure out how to make the supercharger less efficient.

What is the diameter of the crank pulley on your car? Stock STS-V is 5.88" Supercharger pulley is 2.8"

gettinblown
08-02-13, 01:22 PM
Hey you're preaching to the choir, brother, running sans water cooling certainly isn't the end of the install, I've got no plans for that arrangement to be permanent. ;)

All I was getting at was that it'd be really handy for the sake of this project if we could retain the factory pulley yet lower the initial maximum boost output for tuning or maximum power output's sake. Speaking honestly, I know my factory auto transmission, despite its upgrades and setup, will not live long at 12 psi the way I like to drive, and others who fear more for their engines lives also don't want to run that kind of boost pressure immediately, or permanently. We may want to limit the boost to 8/9/10 psi, for example.

So now that we know we can lower/limit that assemblies maximum boost output by merely tweaking the boost signal going back to the vacuum actuator, it gives us one less hurdle for the projects development, as well as an ability to "stage" the initial install and run-in. There are plenty of 4/5/6psi supercharger packages out there that aren't cooled at all, and I have a hard time believing that that blower running at say half its intended output isn't efficient, and still adding useable power to an engine.

I just roughly measured my crank pulley lip-to-lip best I could at about 5.75" inches diameter, but the belt rib diameter is probably closer to 5.5" diameter, so would that help lower the maximum boost output, or doesn't a smaller pulley mean more boost, or is that only on the supercharger itself....

TimmyC
08-02-13, 01:48 PM
If you come up with a device that can modulate a 12v signal you can use the factory boost control solenoid to open the bypass valve at a set boost pressure. The factory setup opens the bypass when there is vacuum between the throttle body and the supercharger rotors, aka, part throttle. This is done for mileage and supercharger longevity. Once there is no longer enough vacuum (half to full throttle) to operate the bypass valve actuator, the valve closes and you get boost. The only way to open the bypass valve while in boost is to apply boost to the other port on the bypass actuator. The computer uses the bypass solenoid to do this under certain conditions. It does that in reverse and if you exceed 159mph for more that there's minutes as well as when some faults are detected. Boost won't go to zero because the bypass is not big enough to over come the airflow of the supercharger.

You need something to modulate the bypass valve at your desired boost. I think an electronic boost controller works the same way to block air going to the top of the waste gate. This is the opposite but the controller would be the same.

06 STS Rob
08-02-13, 02:01 PM
I just roughly measured my crank pulley lip-to-lip best I could at about 5.75" inches diameter, but the belt rib diameter is probably closer to 5.5" diameter, so would that help lower the maximum boost output, or doesn't a smaller pulley mean more boost, or is that only on the supercharger itself....

Smaller crank pulley will lower boost, smaller blower pulley will raise boost. Think of that part like you would a motorcycle chain. The gear ratio changes with sproket diameters (teeth).

gettinblown
08-02-13, 03:11 PM
If you come up with a device that can modulate a 12v signal you can use the factory boost control solenoid to open the bypass valve at a set boost pressure. The factory setup opens the bypass when there is vacuum between the throttle body and the supercharger rotors, aka, part throttle. This is done for mileage and supercharger longevity. Once there is no longer enough vacuum (half to full throttle) to operate the bypass valve actuator, the valve closes and you get boost. The only way to open the bypass valve while in boost is to apply boost to the other port on the bypass actuator. The computer uses the bypass solenoid to do this under certain conditions. It does that in reverse and if you exceed 159mph for more that there's minutes as well as when some faults are detected. Boost won't go to zero because the bypass is not big enough to over come the airflow of the supercharger.

You need something to modulate the bypass valve at your desired boost. I think an electronic boost controller works the same way to block air going to the top of the waste gate. This is the opposite but the controller would be the same.

I like the idea of your statement I highlighted. We could, for initial run-in, plug the bottom of the bypass valve straight to the boost signal on the supercharger then. Sure, it may only make 1/2/3 psi, but it'd be a perfectly safe starting point to check for leaks/belt alignment, etc, then start playing with the tune as we up the boost. I'm certainly not trying to sound like I'm against spending money on this project, but if all we need to do is have control/modulate the boost signal going back to the top of the actuator, that can be done for practically nothing, a mechanical bleeder valve/regulator would do, or even an orifice tube slipped into the hose, to restrict the airflow. Well that certainly gets the gears rolling, thanks Timmy!


Smaller crank pulley will lower boost, smaller blower pulley will raise boost. Think of that part like you would a motorcycle chain. The gear ratio changes with sproket diameters (teeth).

Thanks Rob, I thought I was thinking right, but I'm much more confident in my turbo knowledge than SC operation.