Looks Like I'ma gonna be a Caddy Guy - Now What? Stroker L92 LS3 Build

[Slidin Gator]

But damn did they have to make the intake so damn ugly




The friggin thing is 2-1/2 feet tall!

 

[Slidin Gator]

Here are the torque specs I am using and the intake torque sequence. This intake calls for 2 passes, 4 ft-lb on the first and 8 ft-lb on the second. I don't do inch pounds.

 

[Slidin Gator]

Next on the list. These should be big enough to flow whatever mixture I come up with.

 

[BobBrack]

Aftermarket manifolds arent that expensive and look great.

 

[Slidin Gator]

Aftermarket manifolds arent that expensive and look great.

10-4 on that Bob, but those aftermarket units are tuned for higher revs. I'm not looking to turn past 5,500.

So ugly it is!

 

[Slidin Gator]

More fun and games, this time with injector dimensions. I'm running the L92 intake from a 2008 Escalade but otherwise building a stroked LS3.

It turns out that even though the injectors for either engine are called EV6, they are different lengths. The "Truck" injectors are 47 mm O-ring to O-ring, the LS3 "Car" injectors are 40 mm. Since the market for people trying to soup these engines up leans heavily towards big Revs, the upgrade support for this intake is limited. The tech at Holley that helped me pick the injectors out last year didn't catch this and I had no clue . Not bad mouthing the dude, he was extremely helpful sorting lots of stuff out.

I called Holley Tech support this morning, talked to another guy, told him my story. The first option he came up with was to use some ICT Billet injector adaptors. I had looked at these already, the problem is they add 1/2" and I'm dealing with 1/4" (7mm delta). Ultimately, I need to upgrade the fuel rails to 1/2" anyway to support E85, so I asked about the LS Truck Fuel rail kit (534-244) running the LS3 injectors and #8 AN fittings. He told me to hang on.

Holley EFI 534-244 Billet Fuel Rail Kit for LS Truck Intake

After 15 minutes the dude came back and told me he had test fit the exact same fuel rail and injectors on a Trailblazer intake. Apparently, the Holley tech guys have a lab full of parts to check fits out on. Unfortunately he didn't have my exact intake, but he told me those injectors, fit the Group B bracket (A-E bracket sets in fuel rail kit) fit within ~2mm. I ordered the setup and AN-8 fittings for my future 1/2" fuel supply, looks like there is some shimming, grinding and/or welding of some fuel rails in my near future.

 

[Slidin Gator]

For reference, here is the OEM fuel rail setup. If I were to modify the mounting tabs to resolve the 1/4" difference (drop the fuel rail) I would need a new cross over pipe. Ultimately, I end up with a 3/8" sized supply, time to spend my way out of another corner.

 

[Slidin Gator]

Here are some of the key references I looked at to sort this out. They definitely could have done a better job standardizing injectors, or at least documenting the differences! The last thing I want to do on an airboat is install "Injector Adapters" with the extra 8 O-rings to leak etc.!

Fuel Injector Spacer Set of 8 Truck Intake Manifold to LS3 Injector Adapter

I could run the OEM fuel rails with a set of 1/2" extension adapters on the injectors and 1/4" of spacers under the mounting tabs.

That's what I'm trying to avoid.

LS Fuel Injector Guide

 

[Gary S]

My old continental is looking better and better.

 

[One Eyed Gator]

I run the 12612411 with is 36lbs with the same 534-244 rail for the TBSS intake. works great
With new motor I am Swapping to 12613412 with is 50lbs. work with same rail and mount.

139.00 a set (new take offs) from Glenns auto Performance

You think it's ugly now wait till you get the rail the wiring and the throttle cable on it.

 

[Slidin Gator]

You think it's ugly now wait till you get the rail the wiring and the throttle cable on it.

No doubt, I've been trying out the wiring harness routing and thinking this thing is gonna look like Einstein's hair!

I have 3 questions for you or anyone else:

1. Where do you have your IAT/MAT (intake air temp) sensor located? I can tap a thread into the flange of the intake, just behind the throttle body, but I'm not thrilled with threads in plastic. The other option is a spacer between throttle body and K&N air filter, but I'd rather just plug the air filter direct to my FAST 92 mm cable operated throttle body.
2. What kind of PCV circuit do you recommend? The OEM setup is 3/8" based and appears to be a simple fixed orifice setup via the valve covers. I am thinking of drilling out the driver's side fitting to make it free flowing adding an in-line adjustable PCV valve between it and the intake. On the Passenger side back straight to the throttle body port on filter side of throttle with 3/8". Anything else to consider?
3. Do you use a 2 or 4 corner steam setup? I am wondering if I need to drill out the bellhousing end plugs to add steam plumbing to the prop end.

 

[Slidin Gator]

I run the 12612411 with is 36lbs with the same 534-244 rail for the TBSS intake. works great
With new motor I am Swapping to 12613412 with is 50lbs. work with same rail and mount.

You do got the right plan for sure on the low cost 50 lb injectors from the flex fuel engines, they will flow plenty on gas for your increased power.

The OEM injectors that were installed are per the charts posted for an L92 - GM 12580681 at 30 lb/hr. My self-imposed specification calls for flex fuel ready, so I ended up with 76 lb units.

 

[One Eyed Gator]

I put the IAT just behind the TB on passager side of intake there is a OEM fitting there now. I cut it of drilled it out tapped it and screwed in the sensor with a dab of ultra black. Been like that for 3 years

Off the front passage cover I have a line that cross the front of the motor to a vented catch can and used a filter off the rear driver side. Seems to work ok

Current 6.0 motor has 4 corner which I would prefer but new motor the 799 heads were not drilled iout the back so I have 2 corner steam tube for the front I have an extra 2 corner tube and was just going to intall it on the rear. I got the heads on before I realized that they were not drilled.

Sent you a PM

 

[Slidin Gator]

I went with the 160 Amp alternator, got some accessories planned. But damn, this thing weighs as much as the winch I got rid of years ago!




Summit Claus came by Monday, now I'm here at fit up. Looks like I got more metric threads to get rid of, been adding a lot of SAE Helicoils as I go. Should be simple in the future, the steel stuff is metric, the SST is SAE. Definitely gonna convert all the accessories to SAE.




I initially started laying out the wiring harness from the bell housing end, then I remembered I was working on my boat not car project, so then I started thinking about running the Holley wiring harness from the other end. It will work, but I will definately need the ignition coil extension cables plus a few other tweeks to shorten or lengthen various sensor cables, primarily the 2-wire oil pressure sensor cable.

 

[Slidin Gator]

Current 6.0 motor has 4 corner which I would prefer but new motor the 799 heads were not drilled iout the back so I have 2 corner steam tube for the front I have an extra 2 corner tube and was just going to intall it on the rear. I got the heads on before I realized that they were not drilled.

OEG,

I did some research on this. The standard factory plug system for the bellhousing steam ports (prop end) are rivets. All of the LS forum stuff I read says take them out when the heads are off and I'm not of the mind to chance the drill out or take the heads off.

From what I read, GM quit using the bellhousing steam ports once they figured out that engines normally sit balancer end up and the bellhousing plumbing was excessive. For a boat, assuming proper venting on the balancer end, the boat is normally bow up, doesn't that solve?

I'm looking for a bad experience reason that I need to address the bellhousing steam ports vs. leave them as is and focus on venting the rest of the cooling system.

 

[Gary S]

Don't have any experience, but it would be a lot easier to do it now than later. And me personally I would hate to find out later I should have drilled and didn't.

 

[kwanjangnihm]

Next on the list. These should be big enough to flow whatever mixture I come up with.

View attachment 98210

Gotta go big or go home, soon to be CM guy!!

 

[Slidin Gator]

Gotta go big or go home, soon to be CM guy!!

View attachment 98252

Don't you worry Kwan, I'm going big enough.

Why you putting 80 lb Sig prop on your rig? 60 mm kinda skinny too.

P.S., do the math, 8x 76 is bigger than 6x 80.... 6x80=480 Hp, simple as that!

 

[Slidin Gator]

Don't have any experience, but it would be a lot easier to do it now than later. And me personally I would hate to find out later I should have drilled and didn't.

Gary,

I really do appreciate the input. I have thought about it and researched it etc.. There are times that I hit my rig hard to climb a hill and then flip around and point downhill and shut off after cool down. These are the times that a 4-corner steam kit earns it's keep, but do I need it?

The reason SBC engines don't need steam vents (400's not withstanding) is because the thermostat is up high and vents the heads under normal conditions. The SBC setup without steam ports seems to work for most setup, including the boats that park nose down. I gotta say it is cool to work on an intake setup that has no coolant to deal with!

Plenty of small blocks climb a hill, flip around and shut off. Waterthunder is delivering airboat engines with the 2-port setup on the balancer end. I think that's how I'ma gonna roll.

I see the info below pop up in a few LS threads, but I can't find the original source to confirm.

Ls head steam port plug

Pratt & Miller (Pratt & Miller Engineering New Hudson Michigan) and Dr. Jamie Meyer (head of GM Performance) both say that the rear two should stay blocked off.


Jamie Meyer says...

I used to advocate having fittings that went to -4an on all 4 steam vents feeding into a coolant swirl pot, which then drained back into the lower hose or return heater line... this is a setup that was used successfully by a few race teams, but it looks like this was a band-aid once I got 'real' information from REAL race teams.

The issue is not flow - the coolant passages flow plenty - it's pressure.* When driven hard, engines need coolant pressure to "scrape" the steam bubbles that form on hot spots in the head off the wall of the passage.* With all 4 ports open, there's not enough pressure locally (in the head) to promote proper heat transfer unless you run your overall coolant pressure extremely high (30psi or so).* Indy and F1 cars run MUCH higher than that, due to higher hp/liter (heat concentration).

The proper setup all my LSx racers are using is, assuming the top of your radiator is below the steam vent port:
*The rear vents blocked off, the front tee'd (LS6-style).
*Radiator cap replaced with "open" cap (free flow through radiator overflow port)
*Steam vent tee and radiator "overflow"/free flow feeding into coolant swirl pot (aka expansion tank)
*Swirl pot has pressurized radiator cap, bottom drains to non-thermostat-controlled water pump return

 

[Slidin Gator]

While on the subject of the cooling system, might as well unpack some of my lessons I have learned about these engines.

For starters, the LS cooling system places the thermostat on the SUCTION side of the water pump vs. the OUTLET side of the engine like a SBC. The thermostat also includes a check/relief valve that allows Engine OUTLET to recirculate into the pump SUCTION when the thermostat is closed. The advantage of this setup is that it re-circulates engine water past the thermostat during warm up so there is not a situation where the water is hot but the thermostat does not see it. This circuit is designed to bring the engine up to operating temperature as quickly as possible. The old SBC scheme of drilling holes in the thermostat is roughly useless on the LS.

The fact that the thermostat is on the SUCTION side of the pump places it down low, hence the steam/air ports for full bleeding of the cooling system.

I have been using 2008 and 2009 Corvette with LS3 somewhat interchangeably to purchase parts for this build. It turns out there is a change on the water pump between the two years. The change involves 3 things:

1. Location of radiator return
2. Dimensions of the thermostat/check valve
3. Dimensions of the thermostat housing/cover

Start with radiator return. On 2008 and below water pumps (the pump I ordered), the return is on the passenger side of the drive pulley like this picture of my build.




The 2009 and up water pumps have the radiator return on the drivers side. Thanks to One Eye Gator for the pic, love the paint color choice (Lycoming Grey), great minds think alike!