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This is all great info. I was planning on making a similar information thread when I eventually LSA-blower-on-alloy-5.3-block engine swap my BMW in several years, but you are already doing this for me! Thanks!! Haha
Here is the plan:
-Recam
-Keep everything else the same: I have 10.5:1 CR with Mahle forged rods/pistons and a stock crankshaft
I've run over the accessory changes in the Forced Induction section (link above), but I'll repost here.
If you're just sticking to stock boost, there are 6-rib drives for truck spacing from both LSX Concepts and ICT Billet, but I'm going to overdrive the supercharger so I elected to use the 8-rib for the supercharger and Corvette spacing for the rest of the accessories.
Accessory Drive BOM:
--LSA balancer
--LSA/C6 water pump
--ICT Billet alt/PS bracket for Corvette spacing
--Any LS alternator EXCEPT CTS-v
--GM Type II power steering pump (info here) OR C5 power steering pump and pulley (see next post) ----This reservoir fitting if using a non-remote reservoir pump
----Older Type II pumps will need to be modified, see below
--OPTIONAL: High-mount AC bracket (ICT and LSXConcepts both make one, I was able to reuse my own design)
--C6 belt tensioner (Dayco PN 89616 for referenece)
----Attached to the AC bracket, otherwise it would attach to the water pump
----The 75mm ribbed pulley off of the tensioner is used as an idler on the AC bracket
----Smooth pulley for the tensioner
--Belt TBD
The ICT Billet bracket was inexpensive enough to warrant its purchase over designing my own. It was designed for a C5 Corvette power steering pump, but that is essentially identical to the older Type II and I was able to modify the bracket to work with an older Type II pump that I have. The Type II pump will not work due to pulley spacing. I looked at just using the Corvette pulley, but the shaft diameters are different.
Accessories installed. The idler and tensioner are close but won't touch during normal operation AC bracket spacer calculations AC bracket design with idler and tensioner Alternator and PS pump installed (no PS pump pulley). I will redo the steam line.
Last edited by hookemdevils22; Jan 10, 2020 at 12:08 PM.
Thanks for the rundown. With 10.5:1 static CR, I assume you will run a cam with more overlap than a stock LSA (which has 9.1:1 static CR) to achieve an appropriate dynamic compression ratio? I haven't explored building for boost, but I understand ring gaps are usually increased to tolerate higher temperatures. Do you know what your gaps are currently on the top and second rings? How much boost and what power output are you targeting?
*EDIT* As a point of reference, my NA build with 10.25:1 CR and 4.030 bore has 0.019 and 0.021 top and second ring gaps respectively as recommended by my local builder. As another example, this guy running an LSA with 4.070 bore with a dished piston (doesn't say CR) targeting 16psi boost was told by Wiseco to use a 0.028 and 0.030 top & second ring gaps. I understand not gapping rings enough for boost can quickly lead to failure.
Last edited by -TheBandit-; Nov 12, 2019 at 06:05 PM.
I gapped the rings myself, and can dig them up but it’s not a max-effort build so I’m not terribly worried about CR or ring gap, especially given the popularity of LSA installs on LS3 Camaro (10.7:1).
The cam will have a larger LSA to minimize boost bleed-off. I’m leaning on a CamMotion PD cam.
Bad news... the Type II pump and pulley I have don't align with the Corvette spacing. I should’ve seen that coming. Welp. I’ve ordered a C5 aluminum pump, pulley and universal reservoir. I will also need new fittings.
Last edited by hookemdevils22; Nov 13, 2019 at 02:23 PM.
Bummer on the pulley alignment. With regards to the ring gaps, I'm just advising to look into it. Just because the masses have done it doesn't mean it's right or that it wont be your turn to be that guy with the blown engine. Also when you refer to all these guys successfully running LSA superchargers on their stock bottom end LS3s, what boost level are they running? Are you going to stay at a conservative boost level or will the temptation of a future pulley swap put you into the danger zone? It's not fun pulling pistons and regapping rings but it's realllly not fun blowing an engine.
The LSA runs at about 9psi with stock pulleys, which is what I will run (3.0" supercharger / 7.8" crank). Magnuson doesn't recommend opening up rings using their 2.3L blowers with lower boost, and I've asked around; the consensus is that I should be fine until I up the boost. Since I already have a Lingenfelter hub and 2.6" pulley, it's a matter of when not if.
Now that I've finished the accessory drive, I can focus on the supercharger and heat exchange system. Items left to purchase (though I'm sure that I'm missing something):
I've installed the Corvette pump. I was able to get it fired up with a temporary reservoir and all seemed fine, but I need to figure out a permanent solution. The Corvette reservoir looks like it will interfere with the LSA inlet and throttle body, but I'll likely need to create a bracket for the CTSv reservoir. ICT Billet bracket showing Corvette reservoir. LSA showing PS reservoir for reference. LSA PS reservoir
I settled on the LSA reservoir sitting just inboard of the alternator. I created a bracket that allows it to just clear the hood. I'm out of town and wasn't able to get it installed, but should be up and running next week.
Upper is from a 2002 Chrysler Voyager 3.3 liter. Lower is from a 2005 Silverado V8. They require some light trimming. Hat tip to kirk69nova for info.
I finally got it buttoned-up and did a shakedown run (aka dropping kids off at school followed by commute). I might actually have to relocate the reservoir again when I install the supercharger, but I'll figure it out when I get there. I did have to bend the front steam tube, but I understand that this is needed for the LSA anyway.
The red wire from the alternator is for the "S" pin, which senses voltage at the main power distribution. I added this after the fact and it solved my low alternator voltage issues. The unused holes at the top of the bracket are for Corvette alternators.
Quick update: I'm steadily collecting parts, but still have some biggies to order (heat exchanger and associated hardware, ZL1 lid, cam, LS9 fuel rail, supercharger drive).
So I'm still mulling what to do with the SC drive. My high-mount AC means I can't use the OEM setup. LSXConcepts.com make a simple drive, but it's $350 for a belt, tensioner ($150 on ebay) and piece of milled aluminum and isn't recommended for overdrive pulleys. I'd like to figure something else out.
I've also been looking at heat exchangers. The LSA uses air-to-water, so I don't have to shove a giant HX in front of the radiator like our air-to-air comrades. I've found that AFCO's ZL1 replacement, PN 80283, is a popular choice. It's 26x11x3". I need to check whether it would work, especially with my AC condenser. I've also considered finding a HX to stick toward the back of the car, with its own dedicated fans. I could then stick a big reservoir tank in the trunk, and use the fuel pump turn-on signal for coolant pump and fan relays since the Vaporworx ZL1 pump module is back there. Ideas?
Last edited by hookemdevils22; Jan 20, 2020 at 10:51 PM.
Personally I like the idea of using the ZL1-style intercooler up front. It may be tough to package, but I don't think a rear mount will perform as well and I don't like the idea of additional fans, plumbing, and wiring. My only hesitation is the intense summer heat you have to contend with for AC and engine cooling performance. Somehow they make it work on the ZL1 and CTS V, so that's what I'd try for. For fitment I'm sure you will have to revise or remove the hood latch support and worst case you might need to rework your radiator mounting to shift thing closer to the engine, assuming you have room to do so. Or perhaps you can find a thinner intercooler with larger length/width.
So the thing about the ZL1 HX is that it is 26” across, with the brackets an inch or so outbound of that. That means it will span my 26” radiator opening, although the side tanks will restrict airflow a bit. It is also about 2.5”, which is nearly the distance between my AC condenser and radiator. A 3” depth would’ve required a little clearancing, but 2.5” will only necessitate new brackets (or likely just spacers).
The only issue is the hot Phoenix summer. However, I measured my shroud and found that if I were to move the fan as far to one side as possible, it would clear up enough space to fit 2 small (8” dia) fans on either side. It’s not much, but I could tie those two into my high-speed wiring. Spal makes 7.5” diameter fans that flow just over 400 cfm, which would theoretically provide an additional 800cfm of cooling airflow (obviously less in practice).
Last edited by hookemdevils22; Jan 28, 2020 at 10:17 AM.
I have almost no space between my radiator and condenser. Seems like you'd want it in front of the condenser because the condenser runs at higher temps. What's the order of the stack on the OEMs? Intercooler up front then condenser then radiator?
You're right, it should actually be in the very front. That will complicate things just a little, as I will need to make my own brackets. I double-checked the VA instructions, and it's installed correctly. I'm not sure why they spaced it so far off the radiator except to simplify the bracketry. I'll pull it closer to the radiator.
I don't know if you were following along with my build, but hated the VA mounting/positioning so much that I made my own mounting tabs and tossed their brackets & prebent hardlines in the garbage. I was unhapy that (1) there was a big gap with the radiator and (2) the condenser was not centered in the radiator opening. See post #969 in by build thread for an explanation and photos of how I mounted it.
Noted. I'll use that as a template for mine, though I really don't want to redo the hard lines. I'll try to make a couple gentle bends when I suck it into the radiator, though I doubt I'll be able to center it like yours without redoing them completely.
I took some more measurements and pulled the trigger on the Afco ZL1 unit, PN, 80283NDP, which is 26" x 11" with dual 1" rows. It's a dual-pass unit with both inlet and outlet on the driver's side. I'll dive into the front when I receive it.
I'm still working out the supercharger drive system. I bought an OEM tensioner and plan to add an idler on the slack side near the supercharger pulley. I won't be able to really dig in until I get the supercharger on the car and double-check that my measurements and maths are correct.
So I installed the blower and have it nearly done.
I purchased an OEM LSA tensioner, but the provision for a breaker bar to relieve tension is opposite the pulley rather than integrated into the arm, and it hit the hood. Luckily Gates and Dayco have pretty good online catalogs and I was able to find something that should work. I'm waiting on that so I can finalize my AC/tensioner bracket and figure out belt sizes. I'll also need to put together a PCV system. Any of you boosted fellows want to point me in the right direction? Oh and the hood hits the supercharger (I closed it off with fiberglass last summer), and the grill will need to be trimmed to fit the heat exchanger (turns out it's 3" not 2.5" like I thought!).
The last major hurdle is tuning the car. I don't have HP Tuners, so I'm asking if anyone has the MPVI hardware that I could borrow or rent to get my feet wet. PM me please. I realize I need to download the VCM suite and buy credits, which isn't an issue. I'm merely looking for the hardware for a short period, maybe a week or two. And if I get the hang of it I'll ship it back and buy my own.
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