Pat's Ebay Turbo Compound Boost Build
#841
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Got the new trans. Fluid in the new one arguably looks better than the new stuff in the bottle! I was actually thinking the guy that sold it to me must have poured clean fluid in the converter to make it look that clean. Pulled the pan, it's pristine and same clean fluid. So that is nice!
Old trans had about 400 miles the fluid, and the fluid is so hammered... Thin, and very contaminated. Bad.
I decided I'm going to pull the valve body apart on the old one, see how hard it would be to adjust the line pressure regulator and shim the accumulators. If it's not too bad, I'm going to do that to the new one before installing it. It looks like there's a 100 bolts to get the valve body out.
Old trans had about 400 miles the fluid, and the fluid is so hammered... Thin, and very contaminated. Bad.
I decided I'm going to pull the valve body apart on the old one, see how hard it would be to adjust the line pressure regulator and shim the accumulators. If it's not too bad, I'm going to do that to the new one before installing it. It looks like there's a 100 bolts to get the valve body out.
#842
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@russian is investigating the option for a custom shift controller right now with rusefi: rusefi.com ? View topic - 2003 Miata Transmission Conroller maybe that would be of interest to you.
#843
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@russian is investigating the option for a custom shift controller right now with rusefi: rusefi.com ? View topic - 2003 Miata Transmission Conroller maybe that would be of interest to you.
SO...........
I pulled the valve body off the old trans, and did some reverse engineering on some of it for the line pressure and accumulators. I ended up messing up that valve body by taking it apart and having pieces fall out of it that I did not expect to come loose. It could be fixed if I knew where they went.
Anyways so after going of over and the FSM on how to build this auto, and some supraforums research on a similar AISIN trans, I decided to just raise the line pressure the easy way*, and shim the accumulators. For the line pressure, there's actually an adjustment on the trans for 3 settings, it was in the middle by default. I put it to high, and then built a custom spacer to essentially create another "setting", so now it's 2 clicks higher than stock.
I have numbers I gotta go through to get an idea of how much this should help, but rough guess is about 16% increase in line pressure. Spec is 141-162, so new range would be 164-189 PSI. Middle of that range is 176, so hopefully I see something close to that on my line pressure test.
#844
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Trans is assembled and in the car. It looks like it's going to work, but I'm having a small problem. The newer trans, while it looks identical to the 99 in just about every way, I found out when I put it in gear on jackstands, the spedometer reads way too high. like 3-4 times too high. Because of this, the car takes off in 1st, and then goes into 4th because now light throttle in 1st takes me to like 50mph.... According to the speedo. 2-3K in 4th was about 180, wrapped the spedometer a lot more than I ever thought it would go!
So with a flashlight, mirror, and neck ache I found the output shaft on the 99' trans has a 4 tooth wheel that the VSS picks up. The 05 has 12 teeth.... So VSS is 3x higher than actual.
Not sure if going to swap to to a 05 TCU, or just cut the wheel to be a 4 tooth. I THINK everything else will work if I fix this.
But to cut the wheel I gotta pull the boost pipe/exhaust/PPF/Driveshaft and then the tail housing, and then I'd need a new tailhousing gasket on trans which would prob take a few days to arrive from mazda. And drain the fluid too...
Will think about it and decide what to do tomorrow.
Can't wait to get this fixed and go for a test drive!
So with a flashlight, mirror, and neck ache I found the output shaft on the 99' trans has a 4 tooth wheel that the VSS picks up. The 05 has 12 teeth.... So VSS is 3x higher than actual.
Not sure if going to swap to to a 05 TCU, or just cut the wheel to be a 4 tooth. I THINK everything else will work if I fix this.
But to cut the wheel I gotta pull the boost pipe/exhaust/PPF/Driveshaft and then the tail housing, and then I'd need a new tailhousing gasket on trans which would prob take a few days to arrive from mazda. And drain the fluid too...
Will think about it and decide what to do tomorrow.
Can't wait to get this fixed and go for a test drive!
#845
Not sure if going to swap to to a 05 TCU, or just cut the wheel to be a 4 tooth. I THINK everything else will work if I fix this.
But to cut the wheel I gotta pull the boost pipe/exhaust/PPF/Driveshaft and then the tail housing, and then I'd need a new tailhousing gasket on trans which would prob take a few days to arrive from mazda. And drain the fluid too...
But to cut the wheel I gotta pull the boost pipe/exhaust/PPF/Driveshaft and then the tail housing, and then I'd need a new tailhousing gasket on trans which would prob take a few days to arrive from mazda. And drain the fluid too...
--Ian
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If you need a way to condition your VR signal to meet the requirements for arduino, I believe Aidan did something like that earlier, using the MAX9926. I also have a few boards from Oshpark (for rusefi), not yet assembled, that do the same thing. LMK if you need something. Should be easy enough to figure out, if your TCM accepts a squarewave- just send in a fake squarewave signal while the car is running and see if it picks it up. My speedometer does.
Edit: Second thought: You can halve the frequency of a squarewave with a flip-flop. Two flip-flops might be even easier than one arduino.
Edit: Second thought: You can halve the frequency of a squarewave with a flip-flop. Two flip-flops might be even easier than one arduino.
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I think I'm just going to tear it apart and either swap the wheel to a 4 tooth if that's possible, or just cut the extra teeth off. I was able to get a gasket locally. Mazda is out of them till March 2017...
#853
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WORKS!!!!!!!!!!!!!
No slipping at all at 20 PSI boost. Spins when it hits second, and it spins going into 3rd as well!!!!!! Gear changes are a lot faster. I would estimate them at about 0.15 seconds for a gear change, feels as fast or faster than my C63 which has a sweet auto in it. Before the 1-2 took 0.9 seconds (all slipping) and 2-3 took 0.25-0.30. Essentially there's no slip, and I cut my gear change times in half! I can't really tell in a log, as it spins with street tires on all the gear changes so you see the RPM's balloon as it spins.
There was a lot of traffic so I didn't get to beat on it as much as I wanted to, but I made two or three 1-2 pulls, several 2-3 pulls, and one 1-2-3 pull. On the 1-2-3 pull, it spun going into 2nd and just lite the tires loose and spun up to redline and then went into 3rd, where it found traction and RPMs dropped suddenly. This trans has no problem holding 20 PSI right now.
Probably going to drive it at 20 psi for a bit just to make sure everything is happy and normal, then turn up the boost. The way it drives now, I think it would take 30 no problem. Maybe more! And I don't have torque management on right now either, so it's dealing with full power on gear changes and not a hint of slip!
No slipping at all at 20 PSI boost. Spins when it hits second, and it spins going into 3rd as well!!!!!! Gear changes are a lot faster. I would estimate them at about 0.15 seconds for a gear change, feels as fast or faster than my C63 which has a sweet auto in it. Before the 1-2 took 0.9 seconds (all slipping) and 2-3 took 0.25-0.30. Essentially there's no slip, and I cut my gear change times in half! I can't really tell in a log, as it spins with street tires on all the gear changes so you see the RPM's balloon as it spins.
There was a lot of traffic so I didn't get to beat on it as much as I wanted to, but I made two or three 1-2 pulls, several 2-3 pulls, and one 1-2-3 pull. On the 1-2-3 pull, it spun going into 2nd and just lite the tires loose and spun up to redline and then went into 3rd, where it found traction and RPMs dropped suddenly. This trans has no problem holding 20 PSI right now.
Probably going to drive it at 20 psi for a bit just to make sure everything is happy and normal, then turn up the boost. The way it drives now, I think it would take 30 no problem. Maybe more! And I don't have torque management on right now either, so it's dealing with full power on gear changes and not a hint of slip!
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Also many thanks to the suggestions on how to get the trans to work with the 12 tooth wheel via software. It was what I was going to do until I was able to get a gasket locally. Once I had that, I figured it would be best to do a hardware mod or swap vs adding more computers/electronics. If that VSS thing ever broke, the trans would go into limp mode which is 4th gear all the time. Can't do that now.
#856
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I'm so thrilled it's working and holding. I haven't done any auto trans work in a long time, and it was intimidating pulling apart a low mile trans that I was sure was in great shape, and risking messing it up! But it looks like it worked, and it's shifting great. I really hope this things holds up to some boost. I think I'm going to take it to the 1/8th mile tomorrow, we'll see.
Plan for now is to swap on the drag radials for traction to get rid of wheel spin, enable torque management (and program it to reduce torque for 1.5 seconds on each gear change, overkill) but only have it pull timing, no rev limiter. Then disable my torque converter control (let stock TCU do that) and then datalog a 1-2-3 pull. Then by reviewing the log to see where it pulls timing, I can see the delay between commanding a shift and it happening by the time between when it pulled timing and when RPMs began to drop, as well as the shift times for each gear. Once I have that data, I can program a delay and exact amount of torque managment time for each gear. Then it should be close to dialed in, and can fine tune off of logs in the future. Then all the boost and see what it will hold!
Plan for now is to swap on the drag radials for traction to get rid of wheel spin, enable torque management (and program it to reduce torque for 1.5 seconds on each gear change, overkill) but only have it pull timing, no rev limiter. Then disable my torque converter control (let stock TCU do that) and then datalog a 1-2-3 pull. Then by reviewing the log to see where it pulls timing, I can see the delay between commanding a shift and it happening by the time between when it pulled timing and when RPMs began to drop, as well as the shift times for each gear. Once I have that data, I can program a delay and exact amount of torque managment time for each gear. Then it should be close to dialed in, and can fine tune off of logs in the future. Then all the boost and see what it will hold!
#858
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I'm so thrilled it's working and holding. I haven't done any auto trans work in a long time, and it was intimidating pulling apart a low mile trans that I was sure was in great shape, and risking messing it up! But it looks like it worked, and it's shifting great. I really hope this things holds up to some boost. I think I'm going to take it to the 1/8th mile tomorrow, we'll see.
Plan for now is to swap on the drag radials for traction to get rid of wheel spin, enable torque management (and program it to reduce torque for 1.5 seconds on each gear change, overkill) but only have it pull timing, no rev limiter. Then disable my torque converter control (let stock TCU do that) and then datalog a 1-2-3 pull. Then by reviewing the log to see where it pulls timing, I can see the delay between commanding a shift and it happening by the time between when it pulled timing and when RPMs began to drop, as well as the shift times for each gear. Once I have that data, I can program a delay and exact amount of torque managment time for each gear. Then it should be close to dialed in, and can fine tune off of logs in the future. Then all the boost and see what it will hold!
Plan for now is to swap on the drag radials for traction to get rid of wheel spin, enable torque management (and program it to reduce torque for 1.5 seconds on each gear change, overkill) but only have it pull timing, no rev limiter. Then disable my torque converter control (let stock TCU do that) and then datalog a 1-2-3 pull. Then by reviewing the log to see where it pulls timing, I can see the delay between commanding a shift and it happening by the time between when it pulled timing and when RPMs began to drop, as well as the shift times for each gear. Once I have that data, I can program a delay and exact amount of torque managment time for each gear. Then it should be close to dialed in, and can fine tune off of logs in the future. Then all the boost and see what it will hold!
With torque management on, it works ok. I think I need to make it more aggressive on pulling power during the gear change, I only had it reduce power some, not a whole lot.
On 25 PSI, it ran a 8.71 @ 91.91 mph, also ran a 8.87 @ 91.76. At 27 PSI it ran 8.92 @ 92.44mph.
60' for these runs were 2.43, 2.33, 2.45!
It is dog-slow out of the hole with a stock converter. Standing on the stall for 3 seconds, it makes 1.5-1.8 PSI boost @ about 2,600. Gutless on the launch. Once it gets into boost it's awesome.
So a converter is at the top of the shortlist, probably a 4,500-5,000 stall. So is a pressure sensor that goes to 250 or 300 PSI so I can datalog line pressure on the trans all the time. I stopped running the car after going to 27 and it not going any faster, looking at the logs it seems the first pass it was perfect on the 1-2 shift, but the 2nd and 3rd pass it slipped a bit on the 1-2 both times. My torque management is programmed to wait a set amount of time, then pull timing for a set amount of time for each gear change.
See picture for detailed info on how it ran at 25 PSI. Some quick stats from the pic:
0-40mph took 4.52s, avg increase in speed of 8.85mph/sec.
40-92mph took 4.35s, avg increase in speed of 11.95mph/sec.
Essentially it should accelerate a lot faster in 1st compared to 2nd or 3rd (from more aggressive gearing of course), but the average of 2nd and 3rd is 35% better acceleration than in first!!! That's because the stock torque converter is killing my launch. In fact 1st gear should show 69% more accel than second, 1st should show 245% more than 3rd. Yet my car pulls harder at 90mph than a 30! LOL
So I need a higher stall converter, and it will make the car a lot lot lot faster.