I did it again!
- Thread starter 6speed
- Start date
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- 92 & 16 Meyatas
nice mike!
Replacement coil installed and test driven fine
While testing it, I took a video to see what my boost was doing, since I can't exactly watch boost while at full throttle. It confirms what I thought I was seeing, a ~4psi spike on boost roll in that then settles down. I'm researching ways to eliminate the spike, so i can have more consistent and flat boost.
Skip to 1:10, a caddy blocked me for the first minute of the video, but i got a good pull from mid 3rd to mid 5th on clear highway. Some say that it might be ~45mph to ~100mph, but that's just unfounded rumor.
https://www.youtube.com/watch?v=6qPhzfH82sU
While testing it, I took a video to see what my boost was doing, since I can't exactly watch boost while at full throttle. It confirms what I thought I was seeing, a ~4psi spike on boost roll in that then settles down. I'm researching ways to eliminate the spike, so i can have more consistent and flat boost.
Skip to 1:10, a caddy blocked me for the first minute of the video, but i got a good pull from mid 3rd to mid 5th on clear highway. Some say that it might be ~45mph to ~100mph, but that's just unfounded rumor.
https://www.youtube.com/watch?v=6qPhzfH82sU
Misfiring, I thought, at idle again this morning. Coils still fine, timing light shows stable ignition still, so started playing with fueling. Looks like I was just going too lean at idle, and I couldn't get my factory front narrowband to read lean at all, and that's the source for my out-of-boost closed loop fuel control. So while the sensors are supposed to fail lean usually, this one just won't ready lean, so it keeps pulling fuel, and it was starting to stumble at idle from a lack of fuel. Cleared the long term fuel trims and richened the idle cells on the table by 0.05ms, and the idle smoothed out, no more stumbling. Probably need to replace the factory NB again. Running open loop for now.
Also figured out one source of my popping noise, also a source of cowl shake I was seeing. The big factory 'butterfly' brace under the car had bolts that were just snug, not tight. Tightened them up and th epopping was reduced, but not eliminated. Since disconnecting the swaybar also reduced but not eliminated the popping, going to do that next to see if the combination clears it up.
Also figured out one source of my popping noise, also a source of cowl shake I was seeing. The big factory 'butterfly' brace under the car had bolts that were just snug, not tight. Tightened them up and th epopping was reduced, but not eliminated. Since disconnecting the swaybar also reduced but not eliminated the popping, going to do that next to see if the combination clears it up.
- :
- 92 & 16 Meyatas
That seems to pull nice mike?
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Sent from my iPhone using Tapatalk
Yes, yes, it does 
An electronic boost controller shipped from Flyin Miata yesterday. It will take some work to get it working right (fortunately Jeremy has done most of the work already), but it should produce a much more stable boost across the board, not to mention it will add in a few more options, like a safety that will cut boost back to the wastegate if the temps get too high, gear dependant boost if I want it, etc...
Gear dependant boost might be used on the track, to limit top speed (for aero reasons) without slowing down the lower gears.
An electronic boost controller shipped from Flyin Miata yesterday. It will take some work to get it working right (fortunately Jeremy has done most of the work already), but it should produce a much more stable boost across the board, not to mention it will add in a few more options, like a safety that will cut boost back to the wastegate if the temps get too high, gear dependant boost if I want it, etc...
Gear dependant boost might be used on the track, to limit top speed (for aero reasons) without slowing down the lower gears.
EBC received and installed. I updated to the latest firmware in preparation for testing it, and immediately found a number of problems that makes the car nearly undriveable on that firmware with my maps. I don't know what, but...it's garbage. Stumbling and hesitations all over the board, even with painstakingly going map by map and setting by setting to make sure that the data transfers completely.
So I reverted back to the old firmware.
However, I also found a thread on mazda-speed.com from CanyonFive about setting up the EBC, and it was on the older firmware that I am on now, so I shouldn't have a real problem with that yet. In that thread however, there was something mentioned that I kind of knew already in the back of my head, but was stressed. The Hydra sees boost at the intake manifold. My manual boost controller has been seeing boost at the compressor wheel outlet. Because of the distance and the intercooler in between, these simply don't match.
I had an "ah ha!" moment, realizing that my ~4psi boost overshoot that I am seeing now vs ~2psi overshoot before was simply because I had a more restrictive intercooler in the stream. CanyonFive also said that it was nearly impossible for him to tune the EBC with the EBC seeing pre-intercooler boost and the Hydra trying to control it from boost at the manifold. It just can't get the target vs actual correct.
So this morning I moved my boost controller signal source over to the manifold (pre throttle body is supposed to be better, however I don't have an easy way to tap that quickly). Immediately I have a 1psi or less boost overshoot, and I had to turn DOWN the boost controller 3 clicks to stay off boost cut (which is at 12.5psi), where as before I was settling at ~8-9psi. Boost also now only drops off by about 1 psi by 6,500rpm, so I'm at ~11 at 3,800, and 10 at 6,500, and it is a very slow taper.
And the difference? The MSM runs "like a scadled cat" compared to before. Significantly faster.
The only noticeable downside at the moment is that in high gear low RPM, the wastegate flutters more exageratedly than it should be, leading to noticeable rapid 'pulsing' in power. I've confirmed that it isn't the AFRs or the timing, or the ignition. I'm pondering solutions, but I suspect that it will mainly just mean finding a way to shorten the signal lines to improve the response time for the MBC.
So my EBC may not be necessary after all. I will be seeing if i can tune the settings to get it to work correctly this weekend, but relocating the signal source solved my current complaints.
So I reverted back to the old firmware.
However, I also found a thread on mazda-speed.com from CanyonFive about setting up the EBC, and it was on the older firmware that I am on now, so I shouldn't have a real problem with that yet. In that thread however, there was something mentioned that I kind of knew already in the back of my head, but was stressed. The Hydra sees boost at the intake manifold. My manual boost controller has been seeing boost at the compressor wheel outlet. Because of the distance and the intercooler in between, these simply don't match.
I had an "ah ha!" moment, realizing that my ~4psi boost overshoot that I am seeing now vs ~2psi overshoot before was simply because I had a more restrictive intercooler in the stream. CanyonFive also said that it was nearly impossible for him to tune the EBC with the EBC seeing pre-intercooler boost and the Hydra trying to control it from boost at the manifold. It just can't get the target vs actual correct.
So this morning I moved my boost controller signal source over to the manifold (pre throttle body is supposed to be better, however I don't have an easy way to tap that quickly). Immediately I have a 1psi or less boost overshoot, and I had to turn DOWN the boost controller 3 clicks to stay off boost cut (which is at 12.5psi), where as before I was settling at ~8-9psi. Boost also now only drops off by about 1 psi by 6,500rpm, so I'm at ~11 at 3,800, and 10 at 6,500, and it is a very slow taper.
And the difference? The MSM runs "like a scadled cat" compared to before. Significantly faster.
The only noticeable downside at the moment is that in high gear low RPM, the wastegate flutters more exageratedly than it should be, leading to noticeable rapid 'pulsing' in power. I've confirmed that it isn't the AFRs or the timing, or the ignition. I'm pondering solutions, but I suspect that it will mainly just mean finding a way to shorten the signal lines to improve the response time for the MBC.
So my EBC may not be necessary after all. I will be seeing if i can tune the settings to get it to work correctly this weekend, but relocating the signal source solved my current complaints.
I apparently fixed my suspension clunk.
I was going to try to raise the suspension a bit to see if that stopped the noise, but then found I couldn't get the collars rotated (left front where the noise has apparently been the strongest). While I was in there I started poking around and realized that I I could rotate the forward lower A-arm ecentric bolt a bit with a wrench. Stuck a wrench on each end and cranked them tight as hard as I could. Took a drive and no noise
I probably messed up something with my alignment a bit, but if it's been shifting then I've probably been driving with a slowly shifting one anyway. Might as well schedule a new alignment, and see if I can dial in some better high speed stability as well.
I was going to try to raise the suspension a bit to see if that stopped the noise, but then found I couldn't get the collars rotated (left front where the noise has apparently been the strongest). While I was in there I started poking around and realized that I I could rotate the forward lower A-arm ecentric bolt a bit with a wrench. Stuck a wrench on each end and cranked them tight as hard as I could. Took a drive and no noise
I probably messed up something with my alignment a bit, but if it's been shifting then I've probably been driving with a slowly shifting one anyway. Might as well schedule a new alignment, and see if I can dial in some better high speed stability as well.
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- 92 & 16 Meyatas
Good on the clunk fix!!!
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Well, dyno day today to get retuned for the FM2 turbo and LS2 ignition.
And it was very nearly a complete waste of 4 hours of dyno time.
The wastegate 6psi numbers were acceptable, if a bit low, 147wtq / 162whp. Not that much lower than my stock IHI turbo's 162wtq/177whp at it's wastegate 8.5psi.
Then we started turning up the boost, and getting more and more puzzled. My tuner said that for the engine size and turbo size, I should have easily been gaining around 10-15wtq and 15-20whp for each pound of boost added. I was getting 7-9wtq down low, and 2-3whp for each pound of boost added. Namely, that boost was being added on roll in, but the boost was just falling off as the revs increased, so that at a base of 12psi, i wasn't holding more than about 6psi at redline.
So we spent a lot of time troubleshooting. Negative results on boost leak testing, spark blow out, coil breakup, wastegate actuation problem, or fuel delivery failure.
AFRs all pretty pegged from 11.2-11.5, spark timing was optimized and he was finding losses from further retarding or advancing. It isn't a fuel delivery problem, as he had trouble pulling enough fuel out past 5,500, it was always running into the 10s and 9s every time we turned up the boost.
The only three possibilities that we could come up with, from most likely to least likely:
- There is a clog somewhere in my piping 'capping' total flow, more probably the exhaust piping than the intake piping
- My recent timing belt job erred, and I am off 1 tooth on either intake or exhaust cams, or both
- There is engine damage already that we are unaware of (and that there are no other symptoms for)
From 3,500 to 5,300, everything is smooth and hugely strong, just falls on it's face after that. Each 1psi increase was only generating about 2-3whp more, over a wastegate 6psi 147/16. My stock IHI turbo did this too, and in fact the boost fall off curve from 1 year ago was virtually identical to this one's, suggesting that whatever problem is causing it existed before the FM2 conversion. Since the only piping left that was in place for dyno'ing last year is the intercooler-to-throttle-body short section and the catback. Even the cat is new and only 4,000 miles old. I struggle to see how that is possible, but have to conceed that it is the most likely since the behavior most closely matches that problem source. Perhaps my prior cat, or the original owner's cat, blew out and is clogging the cat back and I've never noticed? Dunno.
This week I will be removing the cat section and test driving it with a straight dump from the downpipe. I should have a power jump regardless, but curious to see how much of one. Regardless of that outcome, I'm going to then pull the rest of the exhaust, every single piece, as well as the entire intake set of piping, and see if there are any clogs.
If nothing found, reinstalling all that and taking the car to get a compression and leak down test, just in case there is hidden damage somewhere.
Failing that, then in about a week and a half, I'm going to start disassembling the front of the car again to expose the entire timing belt and start really closely checking it against the rather confusing timing marks.
I'd put my money on a clog somewhere though, as unlikely as I think it is. The symptoms/behavior just match it perfectly.
Frustrating though. At least one more track event I have to scratch off my planned list. At least I got my AFRs optimized far better than they were at the lower boost levels, and I can feel the improvement there.
N/A is perpetually getting more appealing.
And it was very nearly a complete waste of 4 hours of dyno time.
The wastegate 6psi numbers were acceptable, if a bit low, 147wtq / 162whp. Not that much lower than my stock IHI turbo's 162wtq/177whp at it's wastegate 8.5psi.
Then we started turning up the boost, and getting more and more puzzled. My tuner said that for the engine size and turbo size, I should have easily been gaining around 10-15wtq and 15-20whp for each pound of boost added. I was getting 7-9wtq down low, and 2-3whp for each pound of boost added. Namely, that boost was being added on roll in, but the boost was just falling off as the revs increased, so that at a base of 12psi, i wasn't holding more than about 6psi at redline.
So we spent a lot of time troubleshooting. Negative results on boost leak testing, spark blow out, coil breakup, wastegate actuation problem, or fuel delivery failure.
AFRs all pretty pegged from 11.2-11.5, spark timing was optimized and he was finding losses from further retarding or advancing. It isn't a fuel delivery problem, as he had trouble pulling enough fuel out past 5,500, it was always running into the 10s and 9s every time we turned up the boost.
The only three possibilities that we could come up with, from most likely to least likely:
- There is a clog somewhere in my piping 'capping' total flow, more probably the exhaust piping than the intake piping
- My recent timing belt job erred, and I am off 1 tooth on either intake or exhaust cams, or both
- There is engine damage already that we are unaware of (and that there are no other symptoms for)
From 3,500 to 5,300, everything is smooth and hugely strong, just falls on it's face after that. Each 1psi increase was only generating about 2-3whp more, over a wastegate 6psi 147/16. My stock IHI turbo did this too, and in fact the boost fall off curve from 1 year ago was virtually identical to this one's, suggesting that whatever problem is causing it existed before the FM2 conversion. Since the only piping left that was in place for dyno'ing last year is the intercooler-to-throttle-body short section and the catback. Even the cat is new and only 4,000 miles old. I struggle to see how that is possible, but have to conceed that it is the most likely since the behavior most closely matches that problem source. Perhaps my prior cat, or the original owner's cat, blew out and is clogging the cat back and I've never noticed? Dunno.
This week I will be removing the cat section and test driving it with a straight dump from the downpipe. I should have a power jump regardless, but curious to see how much of one. Regardless of that outcome, I'm going to then pull the rest of the exhaust, every single piece, as well as the entire intake set of piping, and see if there are any clogs.
If nothing found, reinstalling all that and taking the car to get a compression and leak down test, just in case there is hidden damage somewhere.
Failing that, then in about a week and a half, I'm going to start disassembling the front of the car again to expose the entire timing belt and start really closely checking it against the rather confusing timing marks.
I'd put my money on a clog somewhere though, as unlikely as I think it is. The symptoms/behavior just match it perfectly.
Frustrating though. At least one more track event I have to scratch off my planned list. At least I got my AFRs optimized far better than they were at the lower boost levels, and I can feel the improvement there.
N/A is perpetually getting more appealing.
Last edited:
Hydra graph of the problem showing boost fall off.
http://www.rx8club.com/attachment.php?attachmentid=203814&d=1405547564
http://www.rx8club.com/attachment.php?attachmentid=203814&d=1405547564
- :
- 92 & 16 Meyatas
Mike, did you do a base line dyno?
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Perro del Sol
Member
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- 2003 MSP, Spicy Orange, 2004 Mazda 6 Hatch, 2004 Mazda 6 Wagon
I may have missed this, but Mike do you have cats?
Before the changes? Yes. IT's posted earlier in the thread.
If you mean when I first got hooked up to the dyno this time, then yes, though we weren't concerned with the results, it was just a run to make sure that the existing tune was safe and no knock.
12psi a year ago on that dyno with about the same conditions was 202whp 197wtq.
12psi this time we could only get to 170s wtq and 160whp. Boost just kept falling off to the 5-6psi range at redline. Turning up the boost was only spiking the peak torque a bit more each increase, but not really changing high RPM boost.
The HP line on the graphs was landing in the same point regardless of what boost we threw at it, which really suggests that something is capping the total airflow through the system.
Yes, I have 1 cat, it is a metallic core, 50,000 mile warranty, and sold specifically in the turbo exhausts by FM, so it is pretty much sure to hold up to turbo abuse. And this one was installed with the new turbo, so it only has about 4,000 miles on it.
Well, I have more.
I re-did a boost leak check without turning down the boost controller first (like I did before the dyno day). The turbosmart MBC was audibly leaking, and the more I turned up the boost knob, the louder and faster the leak was, to the point of visibly vibrating the MBC. I connected the air pressure source directly to the boost controller on the signal side, leaving the wastegate line attached, and even at 1psi of air being fed to it, is is leaking slowly from the bleed-off holes in the side. Leaks more the higher the pressure i feed it, as well as the higher the boost is turned up. It would explain why my boost fall off a year ago was pretty similar to the boost fall off this time around. Last time I figured it was just the stock turbo running out of breath and having trouble maintaining boost. I had the same MBC controller then though, and never detected the leak.
However...
Removing the MBC and connecting the signal line directly to the wastegate with nothing in between, I still can't hold boost. I can't even get to the 6psi wastegate, stops rising around 5psi and then falls off to 2-3 psi, which doesn't fit a "cap" to power as much, since that is definitely below the peak power we were getting.
The primary suspect at this point is that the SS studs that came with the kit originally (because the iconel studs were on backorder) have stretched, and the turbine housing is just venting the pressure. I don't hear it at all, if anything the sound becomes more muted, not louder, so I would still think that fits a clog of some sort better.
Well, I am pulling the exhaust later on today, from the end of the downpipe all the way to the tips. Going to inspect it all, and take it for a drive uncorked, and log the boost again. I should have a power gain anyway, but if I can suddenly hold boost, then my exhaust piping is causing my problem.
If I still can't hold boost, then the next step will be to pull the turbo saturday morning, and since the water is going to be drained, I'm going to pull the radiator and sway bar while I'm at it, to check the timing belt's timing for the crank and cams, just in case (but I highly doubt that they are a problem).
And while the turbo is out, I'm going to pull the intake piping to inspect all of that for any clogging/restriction.
Compression test shows all 4 cylinders within 4psi of each other. Numbers are low, but I suspect that is just my $20 tester having it's gauge off.
I talked with the main project/build guy at Flyin Miata, and he insisted that it was a boost leak that I hadn't found yet, and gave me a few different ways to test for boost leaks that could have different results.
Sure enough, I found one. My BOV is practically exploding open in a cyclical rythmn at even a few psi when there is no where else for the pressure to go (everything capped off)
So new BOV time it looks like.
I talked with the main project/build guy at Flyin Miata, and he insisted that it was a boost leak that I hadn't found yet, and gave me a few different ways to test for boost leaks that could have different results.
Sure enough, I found one. My BOV is practically exploding open in a cyclical rythmn at even a few psi when there is no where else for the pressure to go (everything capped off)
So new BOV time it looks like.
