LFX Engine Swap (GM V6) at GWR

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Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

So many are wondering why the engine came out again. It certainly wasn't just so I could add some heat shielding ;)

With the car running I drove across the street for an alignment (sitting in the pic here waiting to go on the rack)...
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On the drive back across the street to the shop, the rear tires locked. Fun times sliding into our parking lot. Motor was seized. Oil pressure was strong and everything was running right so best guess right now is that it was the thing I had feared in the back of my head from the beginning - this engine had come from a donor car that we discovered had been flipped, so if the engine had been running while it was upside down, the bearings were doomed from the start.

Not going to allow this to stop me, I gave myself one day to come to terms with things and began the hunt for a motor the next day. Made some calls and found that Cord Bauer of Catfish fame had a unicorn of a motor sitting around that he was willing to part with - this one from a 2013 with only ~500 miles on it (!!) Thanks Cord!

That engine is here already, and I'm about half way through transferring everything from old engine to new:
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Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

LFX's are growing on trees around here! That's the new motor on the right, with nearly everything swapped over:
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A peek inside the pan from the old motor confirms that yeah those bearings are done! Thoroughly cleaning everything in the oil system before swapping over to the new engine (pan, pickup, adapter plate, lines, cooler, etc.)
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Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Engine is in and fires up. Tying up loose ends right now.

Top of that list is some frustration with the Racepak stuff. Bottom line is it simply can't read any PIDs from the 2012 ECU I have. Not with the OBDII adapter cable or with the CAN hi and low hardwired directly to the dash, despite the fact we can view live data streaming via that same diagnostic connector with either a scan tool or HP Tuners. Racepak themselves have no idea why it can't read this ECU, and I've verified this particular dash will pull PIDs via the adapter cable to diagnostic connector on other cars such as an ND that was here in the shop.

SO... I'm bypassing the 'read the ECU' plan. Wired in a temp sensor for coolant and adding the Racepak GPS module for speed. RPM is the complicated one because these ECUs have no conventional tach signal output. Autometer tach signal adapter part number 9117 was the solution.

Pic here shows how it's wired in, this was just temporary crimps to verify it worked before wiring it in properly...
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The signal adapter gets wired in-line with the two main +12v supply wires that go to the coils, one wire to each bank. Follow the instructions included for an LS engine but your wire color is different. Pink/black is what you're looking for in the LFX harness. Start at the coils and follow the light gauge pink/black wires up-stream until you find where they split out from a thicker gauge pink/black. That's the wire to intercept. There are two of these wires, one for each bank. The autometer box outputs a lovely +12v square wave standard tach signal. The Racepak instantly reads it. Change the Racepak to V6 Even Fire (default seems to be V8) and voila. We have RPMs.

Next up was some issues with the oil pressure readings on the Racepak. Using an ACDelco D1800C sensor which is equivalent to the factory Camaro pressure sensor but there is no scaling info available for this sensor. Since we're talking about oil pressure here, I wanted to be able to have complete confidence in the reading so I decided the best approach would be to test it personally and then manually calibrate the Racepak based on those results. So I needed to build a bench tester for the pressure sensor.

Here's what I made. Figured I'd take a little extra time to make something that could be useful in the future. NPT ports for all the common sensor sizes, two air valves so I can fill/bleed and monitor pressure without switching back and forth, portable enough that it can be placed in the engine bay so the sensor is operating on the vehicle wiring. Can be used to bench test temp sensors as well by standing it vertically, removing the end cap, filling with water and then heating the water and validating the temp with a thermometer.
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With the bench tester, I confirmed it's a 0.5v-4.5v / 0-130 psi sensor. However, thanks to testing the sensor this way, I was able to calibrate the Racepack very accurately to the specific scaling of this particular sensor. Dash reads oil pressure perfectly now.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Tons of things going on, a lot of it is little details. Need a small bracket here or a tweak of something there and before you know it many hours have disappeared.

Some of the big stuff...

The Getrag diff was not operating like an limited slip unit. At first we chalked it up to the fluid and additive still needing to get cycled around better since it hadn't driven around much, but after a lot of figure 8's in the parking lot and still no improvement I started digging. GM superseded part numbers so when you call your GM contact to find out if the PN on your diff is for an LSD, they might know that number was superseded by a different number or they miiiiight tell you that's not a number that comes up in their system and have no idea. Eventually we got it nailed down and it turns out the salvage yard that advertised this diff as an LSD unit got it wrong. That was over a year ago so nothing to do now but buy another one.

As for those part numbers...

3.42 NOT LSD:
15793753 - superseded now by 25873499
3.42 LSD:
15793754 - superseded now by 25873500

New diff arrived, correct original PN on it. That diff now lives in the car.
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Lots of little bits here and there to get bodywork on and working. Then went on to hood venting:
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Hood is cut now, finished pics once louvers are back from powdercoating :)

New fence on the splitter to seal behind the lower edge of the bumper skin:
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Plugged all the now-unused holes in the bumper skin that used to feed the oil cooler and front brake ducts. This pic reminds me, still need to relocate that "tow" decal to the hood:
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Went to reinstall the fire extinguisher, discovered the new frame rails blocked the holes the extinguisher bracket had used. Made a new bracket with wider mounting points that tucks the extinguisher up as much as possible under the front edge of the seat:
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Tires arrived and mounted on 15x10 Tungsten 6ULs. This is the 245 Rival S 1.5. Tire tech evolves crazy fast, even from just a couple years ago... back when I was running street tires to fit into a certain class for Miata Challenge I was on the original RS3... then the original Rival came out and it was better because you could actually use the brakes! Now for RLTA and GTA my class requires 100tw or greater, but these "Super200's" are faster than the 100tw options. I'm betting this combo here is easily 2 seconds faster than the old worn out 225 NT01s on 15x9 that I ran at Superlap in 2014.
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Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Managing the air that passes through the car.

Hood venting:
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The louvers pull pressure out of the engine bay to optimize airflow through the coolers and reduce lift. It's rather incredible how well they work - with the radiator just venting into the engine bay like normal the louvers will pull the majority of air that passes through the radiator up and out through the hood. Since this car is about getting that last little bit everywhere, I'm also ducting the radiator's exit up towards the hood vents to maximize front downforce.

Work in progress:
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Finished duct:
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The ducting directs the radiator exhaust directly up to the larger middle two vents and isolates that flow from other pressure sources I'll be playing with in the nose of the car.
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Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

More fab this weekend of various small bits, then drove the car around on the street to do some datalogs. Confirmed, car is loud and moves with urgency.

Back in the shop, mounted up a small wing ;)
This is a Kognition wing I had built back in early 2015 for my car. It served for a brief stint on the GWR turbo NC since my car wasn't using it but now it's finally on the car and ready to be used.
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Curves
Posts: 69
Joined: Mon Jan 09, 2012 1:32 pm
Location: San Diego

Re: LFX Engine Swap (GM V6) at GWR

Post by Curves »

Will that Wing even fit through the gates at Qualcomm :D
How much camber do you in the rear, looks like a lot -3+?
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Curves wrote:Will that Wing even fit through the gates at Qualcomm :D
How much camber do you in the rear, looks like a lot -3+?
Currently -3° Front, -2.8° Rear. Might add a bit more after some testing, we'll see.
Ryan @ GWR
Posts: 497
Joined: Fri Oct 17, 2014 11:37 pm

Re: LFX Engine Swap (GM V6) at GWR

Post by Ryan @ GWR »

Had an awesome weekend at the track. If the shakedown was any indication, there are great things ahead. Jumped right back into another crazy work week here at GWR so I'm still working on getting a bit of a writeup together with pics/vid but will get things up as soon as I can!
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olgzr
Posts: 8
Joined: Sat May 30, 2009 10:45 am
Location: Denton, Tx

Re: LFX Engine Swap (GM V6) at GWR

Post by olgzr »

I’m glad to see it on the track and running. Looks good!
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