Miata LFX Swap (Singular Motorsports & Good-Win Racing)
01-31-2018, 01:29 AM
#784
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Cooking up a bunch of improvements, currently in crunch mode because I'd like to get the car out to Streets of Willow in just two weeks (!!). Will have updates for you guys when I get some time to sit down, but for now here are a few more great pics that surfaced from Superlap Battle, courtesy of Motolyric:
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02-05-2018, 02:15 AM
#785
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Ok time for some updates.
2017 was a big success, and I'm really happy to have some solid baselines and results in the bag. Now, it's all about refinement and MORE in equal parts. In Decemeber with SLB fresh on my mind I did a fresh examination of the car and rulebook and identified anywhere I had room left on the table to maximize performance.
Big on my list is to really hone the chassis and suspension to the maximum possible, within the Limited class rules of course. This goal encompasses both the systems on the car as well as the track-side setup and tuning. A car with all the potential in the world won't do much without putting in the testing and tuning hours to get everything working in unison.
Enter 949 Racing. They need no introduction, these guys are good at a lot of things, but perhaps what they're the best at is setting up a car and extracting every bit out of it. That's not a small talent. Breaking new ground in an underdog chassis, I think a key to success is going to be in getting more out of the car than the competition, and there's a lot I can learn from these guys.
With 949 on board comes a change to the suspension to extract everything possible allowed by the rules; GTA Limited allows 3-way shock adjustment. Ergo, XIDA triples:
I quite like the look of the coaxial top mounts in the engine bay:
Doing sub-1:50's at Buttonwillow has me looking for more roll resistance, even on the street tires. With the downforce I'm seeing race tire cornering loads, and scraping the outer sides of the aero on the track. There's no avoiding I need to go stiffer. The XIDAs come with another jump up in spring rate from my previous setup.
The front sway bar also gets an update. It was one of the last things that's carried over in the build from pre-2017. At GWR we've been working with Karcepts, who make some really nice sway bars for the ND and a couple other chassis. I took some rough measurements and ran a few numbers and worked out that I just might be able to adapt some of the pieces of their ND sway bar to put together a 3 piece NASCAR style bar for this car. I ended up ordering a pair of their beautiful ND arms and their brackets/bushings for the S2000 because the measurements for those looked like they would work best, and a custom Speedway center tube:
Many times in and out figuring out dimensions, checking full range of motion, etc. Had to make a pair of adapter brackets for the sway bar brackets.. here everything is about 90% sorted but I needed to move the endlink bracket on the control arm forwards to shift the pivot slightly. No problem there because those lower arms need to go anyways...
In my factory lower arms I've been running an evaluation kit of press-in spherical bearings that replace all the bushings. Great concept, but unfortunately it turned out to not be the best execution in the product. Most people didn't know that in the final week before SLB I discovered a critical problem in the bearings in the rear lower arms so I ran SLB (and Chuckwalla after that) on factory rear lower arms with 100k mile factory rubber bushings - because it's what we had available at the last minute. Definitely not ideal. Time to get those arms out of the car and replace the front lowers as well to get the last of those bearings out and move on to something trouble-free.
V8R tubular pro series arms arrived. These arrived in bare steel so I could do the custom endlink mount on the fronts:
Then they went off to powdercoating to get finished up. Far more robust bearings in these, strong, awesome:
Just about everything is installed and sorted out at this point, and I'd love to show some pics of everything installed buuuut can't really do that right now because this is the current state of affairs:
Yep, two weeks to go before first track testing of the year, still cranking away on things feverishly
2017 was a big success, and I'm really happy to have some solid baselines and results in the bag. Now, it's all about refinement and MORE in equal parts. In Decemeber with SLB fresh on my mind I did a fresh examination of the car and rulebook and identified anywhere I had room left on the table to maximize performance.
Big on my list is to really hone the chassis and suspension to the maximum possible, within the Limited class rules of course. This goal encompasses both the systems on the car as well as the track-side setup and tuning. A car with all the potential in the world won't do much without putting in the testing and tuning hours to get everything working in unison.
Enter 949 Racing. They need no introduction, these guys are good at a lot of things, but perhaps what they're the best at is setting up a car and extracting every bit out of it. That's not a small talent. Breaking new ground in an underdog chassis, I think a key to success is going to be in getting more out of the car than the competition, and there's a lot I can learn from these guys.
With 949 on board comes a change to the suspension to extract everything possible allowed by the rules; GTA Limited allows 3-way shock adjustment. Ergo, XIDA triples:
I quite like the look of the coaxial top mounts in the engine bay:
Doing sub-1:50's at Buttonwillow has me looking for more roll resistance, even on the street tires. With the downforce I'm seeing race tire cornering loads, and scraping the outer sides of the aero on the track. There's no avoiding I need to go stiffer. The XIDAs come with another jump up in spring rate from my previous setup.
The front sway bar also gets an update. It was one of the last things that's carried over in the build from pre-2017. At GWR we've been working with Karcepts, who make some really nice sway bars for the ND and a couple other chassis. I took some rough measurements and ran a few numbers and worked out that I just might be able to adapt some of the pieces of their ND sway bar to put together a 3 piece NASCAR style bar for this car. I ended up ordering a pair of their beautiful ND arms and their brackets/bushings for the S2000 because the measurements for those looked like they would work best, and a custom Speedway center tube:
Many times in and out figuring out dimensions, checking full range of motion, etc. Had to make a pair of adapter brackets for the sway bar brackets.. here everything is about 90% sorted but I needed to move the endlink bracket on the control arm forwards to shift the pivot slightly. No problem there because those lower arms need to go anyways...
In my factory lower arms I've been running an evaluation kit of press-in spherical bearings that replace all the bushings. Great concept, but unfortunately it turned out to not be the best execution in the product. Most people didn't know that in the final week before SLB I discovered a critical problem in the bearings in the rear lower arms so I ran SLB (and Chuckwalla after that) on factory rear lower arms with 100k mile factory rubber bushings - because it's what we had available at the last minute. Definitely not ideal. Time to get those arms out of the car and replace the front lowers as well to get the last of those bearings out and move on to something trouble-free.
V8R tubular pro series arms arrived. These arrived in bare steel so I could do the custom endlink mount on the fronts:
Then they went off to powdercoating to get finished up. Far more robust bearings in these, strong, awesome:
Just about everything is installed and sorted out at this point, and I'd love to show some pics of everything installed buuuut can't really do that right now because this is the current state of affairs:
Yep, two weeks to go before first track testing of the year, still cranking away on things feverishly
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02-05-2018, 12:58 PM
#787
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Nope, more complexity and even higher cost without much benefit (rules don't allow on-track suspension adjustment). Also, MUCH harder to do napkin math to calculate bar stiffness with a blade arm. I've worked out this bar setup, at least on paper, to have a low end that matches a tubular RB bar, with a high end far above what's available OTS. Will get some real world testing in just a couple weeks to see how it feels.
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02-05-2018, 06:33 PM
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Pic to illustrate why more roll stiffness is needed. This is just a steady corner, not coming down off a bump or anything. Dragging the outer corners of the aero on the ground. At Chuckwalla I could actually hear the scraping as I would turn into "dropzone" at the end of the back straight. I run disposable delrin sliders on the underside of the splitter so I don't destroy it, but am wearing through those quickly:
During post-season inspection I also found scrape marks on the outer front corners of the side skirts. Not sure what corner that was happening in, but definitely a sign of lots of roll.
During post-season inspection I also found scrape marks on the outer front corners of the side skirts. Not sure what corner that was happening in, but definitely a sign of lots of roll.
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02-05-2018, 10:33 PM
#791
I dont really like those mounts, the small fortune bar replaces the whole weak stock sway bar mount and it uses proper self aligning ball bearings instead of fixed delrin ones. Just in case the chassis flexes or gets lightly tweaked they wont bind. Too bad the bar is a custom length and cant just have a different wall thickness at your door in under a week. Any issues with the wheels and tires hitting with the mostly straight arms instead of bent? The gendron bar just clears and it looks like you must be using a longer bar to have that little offset in the arms, assuming they line right up to the sway bar tabs. Jealous of the triple adjustables and all metal control arm bushings though.
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02-05-2018, 10:57 PM
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Leafy -
I don't have any of the factory sway bar mount remaining, my frame rails terminate in-line with the front of the shock tower. The sway bar mounting points are triangulated tubular things, quite strong. I agree that for someone who still had factory frame rail and sway bar bracket there, they'd want something like the small fortune kit that replaces the factory sway mount.
Agreed on the trepidation re: mount bushings/bearings. These use a "low friction, lubrication free, zero deflection solid polymer bearing" (I think "bushing" would be more appropriate). Advantage over a bearing is maintenance-free, but you're spot on that they don't adjust for flex. If they prove troublesome, I'll be making a custom bracket to house a spherical bearing, but I'd like to give these a shot first. They work very nicely on the ND so I'm hopeful.
The center is a standard Speedway bar, perhaps custom is the wrong term - I just mean that it's not the spec Karcepts provides for the ND. Current bar width is 36", so chosen to improve endlink geometry knowing that a road race setup doesn't need full lock, but we'll see how it works. There's room to reduce bar width by up to ~1.5". Can also easily order down a bar in alternate wall thickness, but based on the math I really don't expect to be needing to, these arms have a really wide range.
I don't have any of the factory sway bar mount remaining, my frame rails terminate in-line with the front of the shock tower. The sway bar mounting points are triangulated tubular things, quite strong. I agree that for someone who still had factory frame rail and sway bar bracket there, they'd want something like the small fortune kit that replaces the factory sway mount.
Agreed on the trepidation re: mount bushings/bearings. These use a "low friction, lubrication free, zero deflection solid polymer bearing" (I think "bushing" would be more appropriate). Advantage over a bearing is maintenance-free, but you're spot on that they don't adjust for flex. If they prove troublesome, I'll be making a custom bracket to house a spherical bearing, but I'd like to give these a shot first. They work very nicely on the ND so I'm hopeful.
The center is a standard Speedway bar, perhaps custom is the wrong term - I just mean that it's not the spec Karcepts provides for the ND. Current bar width is 36", so chosen to improve endlink geometry knowing that a road race setup doesn't need full lock, but we'll see how it works. There's room to reduce bar width by up to ~1.5". Can also easily order down a bar in alternate wall thickness, but based on the math I really don't expect to be needing to, these arms have a really wide range.
Last edited by ThePass; 02-05-2018 at 11:12 PM.
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02-08-2018, 09:56 AM
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02-08-2018, 12:37 PM
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Last weekend, with two weeks to go before the first track testing of this season, I was debating whether I should swap in transmission #2. From my post back in January, when trans #2 arrived I was able to confirm that the shifter rod was supposed to pivot - and that the pivot on trans #1 in the car was seized. That's been the cause of my clunky/stiff shifter feel, which is one of two transmission issues I've been dealing with. Issue #2 has been with clutch disengagement, and this one everyone has noticed because you can hear the gear grinding in my videos. Having checked out everything outside of the transmission, we feel confident the issue must be in the relationship between the throwout bearing and the clutch. Can't know for sure without getting in there. January was stuffed full with getting all of the updates/changes in the suspension and brakes on the car because so I can start out early season testing with all of that in place, so this is the earliest I've had a chance to turn attention to the transmission.
I already had measurements for the transmission side of things from trans #2 sitting on the bench. I even bought an MV5 (Camaro version of the transmission) to take the same measurements and confirm first-hand there weren't any differences between the two variants (I'm using the Cadillac MV7):
To get the full picture, we also needed to measure the clutch and flywheel. Based on the nature of the clutch disengagement problems, we expected that when we got in there we would find the throwout bearing is too far from the clutch fingers, and that would be an easy fix - you just shim the slave/TOB assembly to the correct position. On Sunday I dropped the engine/subframe/trans:
I expected I'd pull a long day and have everything back in the car by night with the TOB shimmed to the correct location. With everything out, I measured the clutch and flywheel height, and that threw a wrench in the plans. The TOB wasn't too far from the clutch, it was too close, and by a massive amount. With the trans bolted to the engine and everything at rest, the TOB would already be compressing the clutch fingers by 0.200" (and the fingers only have an intended range of motion of about 0.400"). So the problem is the opposite from expected; I'm over-stroking the clutch.
Left everything on the ground and called SPEC Monday morning. Based on their notes, the stack height from flywheel/crankshaft surface to clutch fingers for their clutch/flywheel assembly should be 3.800" +/- .005". Mine is 4.1"
With the window of time to get everything back together quickly shrinking (The car still needs to visit the alignment shop and the dyno prior to the track) I overnighted the clutch and flywheel back to SPEC. They're working on it now, no word yet but it would appear they manufactured the flywheel with the wrong thickness.
I already had measurements for the transmission side of things from trans #2 sitting on the bench. I even bought an MV5 (Camaro version of the transmission) to take the same measurements and confirm first-hand there weren't any differences between the two variants (I'm using the Cadillac MV7):
To get the full picture, we also needed to measure the clutch and flywheel. Based on the nature of the clutch disengagement problems, we expected that when we got in there we would find the throwout bearing is too far from the clutch fingers, and that would be an easy fix - you just shim the slave/TOB assembly to the correct position. On Sunday I dropped the engine/subframe/trans:
I expected I'd pull a long day and have everything back in the car by night with the TOB shimmed to the correct location. With everything out, I measured the clutch and flywheel height, and that threw a wrench in the plans. The TOB wasn't too far from the clutch, it was too close, and by a massive amount. With the trans bolted to the engine and everything at rest, the TOB would already be compressing the clutch fingers by 0.200" (and the fingers only have an intended range of motion of about 0.400"). So the problem is the opposite from expected; I'm over-stroking the clutch.
Left everything on the ground and called SPEC Monday morning. Based on their notes, the stack height from flywheel/crankshaft surface to clutch fingers for their clutch/flywheel assembly should be 3.800" +/- .005". Mine is 4.1"
With the window of time to get everything back together quickly shrinking (The car still needs to visit the alignment shop and the dyno prior to the track) I overnighted the clutch and flywheel back to SPEC. They're working on it now, no word yet but it would appear they manufactured the flywheel with the wrong thickness.
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02-10-2018, 01:05 PM
#797
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Corrected items arrived back from SPEC yesterday. They say it was a machining error inside the pressure plate that affected the pivot. As soon as it arrived I measured things to verify, finger height from crank surface is now 3.85x" which leaves the TOB about 0.030" of a gap from full compression. We're in the ballpark now.
Reattached engine and trans last night. Should have the engine back in the car today, at which point I'll be back on-track where I was a week ago, but now with one week to do two weeks of stuff. Still holding my breath, I won't declare the transmission issues fixed until I've actually driven it on the track, but if they are then it was all worth it.
Reattached engine and trans last night. Should have the engine back in the car today, at which point I'll be back on-track where I was a week ago, but now with one week to do two weeks of stuff. Still holding my breath, I won't declare the transmission issues fixed until I've actually driven it on the track, but if they are then it was all worth it.
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02-10-2018, 02:04 PM
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That makes more sense now - if the flywheel height was off, the disengagement throw would be shortened but you'd be lacking pressure plate engagement which would appear like clutch slippage. With the pressure plate too thick, it couldn't disengage fully between shifts.
Eager to hear if this fixes it. Loathing pulling ours out.
Eager to hear if this fixes it. Loathing pulling ours out.
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02-12-2018, 02:50 AM
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Drivetrain is back in the car as of today, filled with fluids, test fired, bled, etc. So far I can say for the first time that the shifter feels great! Return to center in neutral feels natural and all of the "clunky stickiness" I had before is gone now. The shift rod pivot was definitely the problem there. Fingers crossed that the clutch engagement issues are equally fixed!
Didn't take any pics today but SuperStreet just released their coverage of Superlap Battle (link here), so here's a shot from them of the engine bay, which is where I've been spending my evenings lately:
Didn't take any pics today but SuperStreet just released their coverage of Superlap Battle (link here), so here's a shot from them of the engine bay, which is where I've been spending my evenings lately:
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02-20-2018, 11:10 PM
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Fuel!
This is the final thing I got done before this past weekend's track day.
So far the car has been running on V8R's '93 octane' tune. Since we only have 91 at the pump here in CA I have been mixing Torco octane booster to bring it up to ~95, or using 100 from the pump at the track. I've been looking forward to changing over to E85 for all the benefits that fuel provides.
As cool as E85 is, the really cool thing is that instead of having to change injectors, do a permanent change over to E85 and a ground-up tune for that fuel, GM already did the hard work for us. Even though the Camaro never sold with a flex fuel feature, some of the other cars that the LFX came in did, and so the engine was designed from the beginning to run E85 and there is a full ethanol tune just laying dormant in the Camaro's ECU waiting to be turned on. That means smooth driveability and reliability of a factory tune, AND with flex fuel the ECU is always monitoring the ethanol content of the fuel and adjusting the tune accordingly, so in a pinch if you can't find E85 you can pour regular fuel right in and the car with sort things out on its own. (Yes I realize most of you guys here already know the merits of E85 )
To enable flex fuel, there is one missing puzzle piece; we need to add a flex fuel sensor in-line with the main fuel supply line. I took this opportunity to replace my stainless fuel line with a pair of fancier - and lighter weight - kevlar braided lines with crimped hose ends. These lines saved a half pound over the stainless line:
The flex fuel sensor is an OEM part number 13577394. You also need a wiring pigtail which can be found all over eBay.
Wire colors on the eBay pigtails may vary, so here are the factory colors at the sensor connector:
pin 1 (Pink/Black): +12v power
pin 2 (Black): Ground to chassis
pin 3 (White): Signal to ECU
1 and 2 are very straightforward. Remember to fuse the power wire.
The signal wire is straightforward but takes a bit of time. This goes directly to the ECU at pin 38 of the X1 connector. Because the Camaro didn't had a flex sensor, that pin is vacant in the Camaro's wiring harness. So, you need a factory pin with a wire tail to add to the connector. If you modified your own engine harness and eliminated some wires, you may have a spare to use here, but I didn't. My overkill approach to this was to buy a second full engine wiring harness from a junk yard and from that I pulled one donor pin and wire from that harness' ECU connector to use on mine. Now I have a spare but incomplete harness I can scavenge anything from if I need it. If anyone else is doing this same thing and needs an ECU pin/wire to add flex fuel, just shoot me an email and I can pull one from my donor harness for you.
Disassembly of the X1 connector is a little tricky, this youtube vid helped me figure it out:
With sensor installed, all that's left is to turn on the flex fuel sensor in the ECU. This is done in HPTuners or similar tuning software. Since the software side isn't my area of expertise, I took the car to Church Automotive Testing in Los Angeles. They're familiar with tuning these high feature GM motors, and using their dyno would enable us to monitor everything to make sure it was working right before I get out to the race track.
For the dyno tuning, I added a pair of AEM UEGO wideband sensors - one for each bank of the exhaust. This allows us to precisely monitor the air/fuel ratio and make sure everything is running correctly.
As the final step of preparation, I drained the tank and then re-filled it with just 1 gallon of 100 octane; just enough to do a baseline run on before switching to E85. At the dyno, we began with the baseline run on the existing fuel and then poured 5 gallons of E85 in. Then the tuner switched on the flex fuel sensor in the software and ran the engine at low rpm waiting for the new fuel to work its way down the line until we began to see the ethanol content rising on the sensor's signal. Once there was a good 75% ethanol at the sensor he did a few more pulls which showed an immediate jump in power. He made a couple minor adjustments to fuel and timing which pulled a couple more hp out of it and improved the low-end torque. More timing beyond that didn't make any more power so we backed it down to the previous timing values and called it great. The good news there is that the E85 tune from GM was already 98% there to max power, we only made tiny refinements. If I was doing it again I'd be confident in just switching on the flex fuel sensor and pouring E85 in the tank. After verifying that the sensor is operating correctly and reading the ethanol, it's good to go drive - no need for dyno tuning or air/fuel ratio monitoring.
So what did we gain? From baseline to final run on E85, +18 whp and +20 ft-lbs at the wheels. And E85 costs ~$2.20 per gallon compared to $9/gal for 100. Works for me.
This is the final thing I got done before this past weekend's track day.
So far the car has been running on V8R's '93 octane' tune. Since we only have 91 at the pump here in CA I have been mixing Torco octane booster to bring it up to ~95, or using 100 from the pump at the track. I've been looking forward to changing over to E85 for all the benefits that fuel provides.
As cool as E85 is, the really cool thing is that instead of having to change injectors, do a permanent change over to E85 and a ground-up tune for that fuel, GM already did the hard work for us. Even though the Camaro never sold with a flex fuel feature, some of the other cars that the LFX came in did, and so the engine was designed from the beginning to run E85 and there is a full ethanol tune just laying dormant in the Camaro's ECU waiting to be turned on. That means smooth driveability and reliability of a factory tune, AND with flex fuel the ECU is always monitoring the ethanol content of the fuel and adjusting the tune accordingly, so in a pinch if you can't find E85 you can pour regular fuel right in and the car with sort things out on its own. (Yes I realize most of you guys here already know the merits of E85
)To enable flex fuel, there is one missing puzzle piece; we need to add a flex fuel sensor in-line with the main fuel supply line. I took this opportunity to replace my stainless fuel line with a pair of fancier - and lighter weight - kevlar braided lines with crimped hose ends. These lines saved a half pound over the stainless line:
The flex fuel sensor is an OEM part number 13577394. You also need a wiring pigtail which can be found all over eBay.
Wire colors on the eBay pigtails may vary, so here are the factory colors at the sensor connector:
pin 1 (Pink/Black): +12v power
pin 2 (Black): Ground to chassis
pin 3 (White): Signal to ECU
1 and 2 are very straightforward. Remember to fuse the power wire.
The signal wire is straightforward but takes a bit of time. This goes directly to the ECU at pin 38 of the X1 connector. Because the Camaro didn't had a flex sensor, that pin is vacant in the Camaro's wiring harness. So, you need a factory pin with a wire tail to add to the connector. If you modified your own engine harness and eliminated some wires, you may have a spare to use here, but I didn't. My overkill approach to this was to buy a second full engine wiring harness from a junk yard and from that I pulled one donor pin and wire from that harness' ECU connector to use on mine. Now I have a spare but incomplete harness I can scavenge anything from if I need it. If anyone else is doing this same thing and needs an ECU pin/wire to add flex fuel, just shoot me an email and I can pull one from my donor harness for you.
Disassembly of the X1 connector is a little tricky, this youtube vid helped me figure it out:
With sensor installed, all that's left is to turn on the flex fuel sensor in the ECU. This is done in HPTuners or similar tuning software. Since the software side isn't my area of expertise, I took the car to Church Automotive Testing in Los Angeles. They're familiar with tuning these high feature GM motors, and using their dyno would enable us to monitor everything to make sure it was working right before I get out to the race track.
For the dyno tuning, I added a pair of AEM UEGO wideband sensors - one for each bank of the exhaust. This allows us to precisely monitor the air/fuel ratio and make sure everything is running correctly.
As the final step of preparation, I drained the tank and then re-filled it with just 1 gallon of 100 octane; just enough to do a baseline run on before switching to E85. At the dyno, we began with the baseline run on the existing fuel and then poured 5 gallons of E85 in. Then the tuner switched on the flex fuel sensor in the software and ran the engine at low rpm waiting for the new fuel to work its way down the line until we began to see the ethanol content rising on the sensor's signal. Once there was a good 75% ethanol at the sensor he did a few more pulls which showed an immediate jump in power. He made a couple minor adjustments to fuel and timing which pulled a couple more hp out of it and improved the low-end torque. More timing beyond that didn't make any more power so we backed it down to the previous timing values and called it great. The good news there is that the E85 tune from GM was already 98% there to max power, we only made tiny refinements. If I was doing it again I'd be confident in just switching on the flex fuel sensor and pouring E85 in the tank. After verifying that the sensor is operating correctly and reading the ethanol, it's good to go drive - no need for dyno tuning or air/fuel ratio monitoring.
So what did we gain? From baseline to final run on E85, +18 whp and +20 ft-lbs at the wheels. And E85 costs ~$2.20 per gallon compared to $9/gal for 100. Works for me.
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