GM LFX 3.6L V6 Motor Swap

[HawaiianMike]

Originally Posted by gtpvette

I feel for you doing it in 3",, just no frickin room. I'm still a bit concerned that it'll rub or bang around,, we'll see. That y-pipe and a single 3" might still be in my future.

Might toss around the idea of a 3" Oval? Might not be worth the clearance you gain or the awkwardness around the rear subframe, but worth thinking about.

[gtpvette]

Exhaust is done. Ended up with three sections. You can see as it comes out of the muffler starts to slant over to one side. Ends up tight against the tank shield and differential.

[gtpvette]

After finishing up on the exhaust,, spent some time on the hood scoop. I glassed up some blocks underneath so I can recess the 9 screws holding it in place. Installed the Riv-nuts in the hood, as a sidebar a couple of them dimpled the hood a bit. I also bondo'ed the scoop and put on some crappy Dupli-Color high build primer. The primer is crap as it wont sand,, just loads up the paper.

Then for the 'pièce de résistance' I tried to wrap it a mat black vinyl. What a total failure. Never tried wrapping before and only bought enough for 1 try. What I got right looked pretty good,,, melting holes in it with the heat gun not so good.

I ordered enough for 4 more tries.

[Ultramaroon]

Originally Posted by gtpvette

What a total failure. Never tried wrapping before and only bought enough for 1 try. What I got right looked pretty good,,, melting holes in it with the heat gun not so good.

I ordered enough for 4 more tries.

This just makes me smile. Thanks for sharing ALL of your build.

[gtpvette]

Haven’t updated in a while, too much other stuff going on to work on the hot rod. That said a couple of updates. Tried to wrap the scoop again, multiple times. OK,,, I suck at wrapping. Part of the problem is there wasn’t a finish coat of paint on it which I think lead to some of the issues when trying to reposition it. That said, went with VHT Wrinkle paint. Sprays on OK,, but the color is still a bit blotchy. The plan was to put a small bead of black caulk under it to help with it sticking and fill any small gaps, that’ll wait for now.

Back to the PCM issue. I did get a new water pipe in from the CTS. Looks like a winner, starts in the back as normal then low on the block and exits below the alternator as apposed to right next to the passanger cylinder head. That gives me room above the original mounting plate I made to mount the PCM. I did make a new mount out of steel,, but it’s super heavy. Will remake in aluminum this weekend if I have time (need to work on boat). After that back to wiring.

I’m also looking at an E85 kit. Time to do it is now if I’m going to do it. There’s a guy on the west coast that’s put one in his track attack Miata and really likes it. Uses the GM E85 sensor and it requires Hot/Ground and one new wire to the PCM. He also says the R85 tune is already in the PCM,,, just needs to be turned on. I’ve already had a mail order base tune done as well as VATS delete so don’t how I’ll get this turned on as of yet. Good news is I would expect about 350HP, 295 TQ at the crank after.

[gtpvette]

Finally got a few minutes to work on the car this weekend. The last 3-4 weeks have been maintenance on the boat,,, a lot of maintenance. That said,,, new aluminum PCM mount is done,, it bolts to the original one I did. As stated earlier, I had to move that radiator pipe swapping it out for one from a CTS. In the one picture you can see how it slopes down from the back of the motor to below the alternator.

You can also see in the picture the new water pipe is bent at a funny angle as related to the radiator output. I think if I cut it and rotate it a bit it'll be OK. Ordered a new 45 degree 1.75 to 1.25 silicone reducer so i'll hold off until that gets in.

Also had to rework the dip stick for the 12th time. Think I'm OK now.

Back to wiring.

[venturaII]

I really like your attention to detail. This is gonna be one clean swap when you're done.

[gtpvette]

In-between messing with the electrical stuff I’ve started looking at the front sway bar as I really need to have one and it’s probably the last major thing to do. With the motor/oil pan setup I have, there’s no way to install a bar behind the cross member unless it hangs below the transmission and or steering rack. I guess I could do it but it’d get hung up on something sooner or later.


That said, I’ve started looking into moving it in front of the cross member. There is some room (4” or so) in between the back of the oil pan sump and the cross member. The only real issue I see at this point is the lack of space between the frame and the OEM lower control arm. With the stock set up it’d be difficult to put any kind of arm on a splined Speedway type bar to make it to the end links. I’ve been looking at the Megan Racing Lower Control Arms and it looks like they might provide the space to make this work. I really don’t want to have to deal with all of the adjustability these provide as I suspect it’ll make alignment way more difficult, but I need the room.




You can see in my crude drawing below how it might work. I suspect the location of the LCA arm that attaches in the middle may be off a bit but you get the idea, blue is new LCA,, red is new bar. Currently looking at the Speedway 1” sold bars, 48 spline. Based on other threads, Andy from Racecomp says the stock front rate is about 140 lbs,, and slightly stiffer would be better. Once I know the arm length I can pick a bar. Multiple holes in the arm for adjustability would be a nice thing if it’ll work without binding. An inch difference in arm length makes a pretty big difference in rate.




I suspect the shape of the arm will be a bit complex but I won’t know for sure until the LCA’s are in. The longer I can make the bar,,, the less complex the arms will be.

[gtpvette]

Couple of updates. Got in a new Aeroforce gauge,, want it for water temp and oil pressure as it displays two items at once. Plugs into the OBD-II plug to scan for information,, pretty slick. The plan is to mount to the right of the gauge cluster.

Got the E85 sensor in,, will wire it into the harness this weekend. I’ll need to rethink the fuel hoses in the engine compartment a bit though. I’ll have Overkill Motorsports do the tune for it.

My Racer-X front LCA’s should be here tomorrow. These are nice pieces, a little pricy compared to some but they allow for adjustment of camber and caster on the car. The good news was they were 10% off on Labor day. Fingers are crossed that I get the room I need for the sway bar. Also, I’ve been researching sway bar rates a bit trying to figure out where I want to be,, target is low 200’s which is a bump over the stock 140lb bar. Think 20MM bar. A lot depends on the arm length which I’m a bit uncertain of at the moment. Picture below shows my rebar mock up,, note the space between the front of the cross member and the rear of the oil pan.

Got the lower radiator hose worked out,, it’ll be much cleaner than the original setup. Still need to weld in a bung on the new hard line to connect to the bottom of the surge tank but haven’t figured out where just yet,, not a lot of room. I also have to change the two hard lines coming out of the motor that connect to the heater hose bungs on the firewall. With the new hard line that routes below the alternator,, the old one no longer fits. It’s always something LOL.

Cleaning up the engine harness a bit. The problem was where the PCM ended up there was way too much wire coming out of the plugs it made a big mess. I pulled all the wires back into the harness to tidy it up some. I’m also rerouting a few sensor wires at the same time. Need to get this finished and wired into the chassis.

[gtpvette]

A couple of updates. Got the E85 system plumbed,, new fuel injection hose from the hard lines up to the 'Y' block, then to E85 sensor then to the motor. I remain a little concerned with the fuel injection hose coming loose and spraying fuel all around,, but we'll see.

Got the Racer-x LCA's in, you can see the difference and there's now at least some room to bring a sway bar up to connect to the strut.

I bought a 1" dowel rod to try a few mock ups. The good news is I think the standard Speedway lengths will work. I need to determine the correct length and the shape/length of the arm though. It's still a bit fuzzy at this point and there's lots of opportunity for binding. I need to determine how much compression and droop I have. This may still not work as everything is really tight.

[gtpvette]

Based on a couple of threads,,, looks like the OEM strut moves about 6” total. Most of that is droop when lowered. The 6” up and down should be range of motion for the sway bar. I think.
I need to scrounge up a OEM strut, mount on the car with no spring and make some measurements and test compression, droop and steering angle.

http://www.ft86club.com/forums/showthread.php?t=26661

http://www.ft86club.com/forums/showthread.php?t=52061&highlight=travel

[gtpvette]

Sway bar work continues. I was sure the OEM bar would work after test fitting. Well,, rubs a bit on the cross member right in the front corner. May be able to grind a bit off,,, but it'll be tight if so. If no go it's back to a speedway bar.

The mounts are for 1" sway bar so moving back to a speedway bar should be OK. As a sidebar,, added a piece of 1" pipe drilled out to 18 MM to sway bar as a spacer.

Also,,, the mounts are a bit more inboard than I would of liked. I did that so there was enough to weld the mounts to and as you move out on the cross member it get pretty thin.

The end links will need to be shortened or replace with shorter one.

[gtpvette]

Well it’s a no go on the OEM sway bar. So,, after a bit of mockup it look like a Speedway Engineering 39” 1” .095 hollow bar is the choice. Based on some other speedway bars as compared to this one (see chart I had to guesstimate some of numbers) and assuming a 5” arm length, it should be in the 215ish range for a rate, up from 140ish for OEM. I think.

I’m going to end up with an ‘L’ shaped arm where one piece is stacked on top of the other. When coming up with a shape, the first issue is the bar is mounted lower than the OEM so the vertical portion of the ‘L’ is taller than the OEM. The next issue is the width of the bar, 39” which is too close to the chassis. By stacking the horizontal portion of the arm on the vertical piece it moves it away from the chassis and it now clears the bolts on the control arms at full droop. With the stacking it puts it at 40.5” wide where the links attached versus 41.5 for OEM. I may still try to bend the horizontal piece a bit to get to that 41.5”

Will order everything next week,,,, so ready to get past this part.


Bar in motion, 1" dowel rod mock up and a few iterations of arms..

[ame]http://youtu.be/c5pszWRc8w4[/ame]

[Ultramaroon]

It may be nothing but I wonder, with the mounts so far inboard, if the bar will respond to the moment couple by bending more than twisting.