I did it again!

[6speed]

Nevermind. According to my logic, which was then backed up by Jeremy at Flyin Miata, my BOV SHOULD be actuating in a boost leak test the way I did it.

With no where else for the pressure to go, the pressure on the bottom of the BOV piston will simulate vacuum pulling on the other side, and overwhelm the spring, pushing the spring back until it vents the pressure, and then closes. Exactly what I was experiencing.

So that prooves that I do not actually have a boost leak anywhere in my intake piping.

Back to the drawing board. Probably going to pull the intake piping first, since my bumper is already off, then exhaust. Look for obstructions.

 

[bazooka joe]

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.

ya, i was wondering if this "restriction" was showing up on the base line dyno

 

[6speed]

Well, the torque fall off on the stock IHI turbo was virtually identical to the torque fall off on this FM2. The tuner said that if he was only looking at the dyno charts and not under my hood, he would swear I hadn't changed a thing. It leads me to believe that my torque fall off originally was far greater than most IHI turbos actually have (which fall off a bunch anyway), and explains why I had good torque numbers lower down but I didn't get nearly the HP numbers I was hoping for. But neither I nor the tuner had any real reason to believe otherwise.

The breathing hardware that was the same then as now:
- Engine internals
- Engine block
- Catback
- Hard pipe after the intercooler
- soft pipe between factory hard pipe and throttle body elbow
- throttle body elbow
- throttle body
- intake manifold
- manual boost controller
...and that's it.

Even all the vacuum lines have since changed. Exhaust piping from the manifold, turbine, downpipe, cat, and midpipe have all changed. Intake piping from filter to compressor outlet to intercooler outlet have all changed. And ALL for the better. So...dunno.

I just got finished pulling, inspecting, and re-installing all the intake piping, nothing odd found at all. I could freely push compressed air through every pipe, nothing fell out. Re-tested for leaks after installing it all, and it still all passed.

Going to pull the cat in the morning and give it a test drive to see what happens. Best way of flow testing the exhaust I think.

 

[6speed]

Clogged cat.

I pulled the cat and immediately could hear the internals rattling before I even got it out from under the car. And shaking it from both directions doesn't empty the insides, which I'd expect at least a bit of dist or something. Too late to test drive without pissing off the neighbors.

Pondering if I should gut it, and get my car back immediately, or just wait and send the cat back to FM for a replacement (4,000 miles into a 50,000 mile warranty), if they will even honor it. If I'm honest, it's likely that my failing ignition and general rich tune killed it rather fast.

I don't mind the smell of a catless rotary, but a catless piston engine smells aweful. The lower restriction may also introduce boost creep on the 2560 from what I read, without porting the wastegate farther.

Edit:
NM, a replacement is ~$150. I'm just going to gut it and order another one. It's not worth having my car undriveable for possibly several weeks, especially with my wife taking her car for several days to see her sister.

 

[bazooka joe]

Clogged cat.

I pulled the cat and immediately could hear the internals rattling before I even got it out from under the car. And shaking it from both directions doesn't empty the insides, which I'd expect at least a bit of dist or something. Too late to test drive without pissing off the neighbors.

Pondering if I should gut it, and get my car back immediately, or just wait and send the cat back to FM for a replacement (4,000 miles into a 50,000 mile warranty), if they will even honor it. If I'm honest, it's likely that my failing ignition and general rich tune killed it rather fast.

I don't mind the smell of a catless rotary, but a catless piston engine smells aweful. The lower restriction may also introduce boost creep on the 2560 from what I read, without porting the wastegate farther.

Edit:
NM, a replacement is ~$150. I'm just going to gut it and order another one. It's not worth having my car undriveable for possibly several weeks, especially with my wife taking her car for several days to see her sister.

glad to hear you figured it our mike! i was wondering what would kill a new cat so quickly, but you answered that quest!!! i don't run a cat and to be honest, i very rarely smell the exhaust...when i do i just try and go faster! of course bruce never liked following me (i think it's because he couldn't keep up )

 

[Reitrof]

glad to hear you figured it our mike! i was wondering what would kill a new cat so quickly, but you answered that quest!!! i don't run a cat and to be honest, i very rarely smell the exhaust...when i do i just try and go faster! of course bruce never liked following me (i think it's because he couldn't keep up )

The stink was something else, like driving thru turpentine.

 

[6speed]

Yeah, just got back from a meet to go drive some fun roads here in PA, and no one behind me even commented on a smell. I can only faintly smell it. I'm surprised. Might be my tune? dunno.

It was coming up to boost faster than before, and holding the set boost all the way to redline though. The car is clearly faster overall at 4psi on the gauge than it used to be at 10psi. Will be re-scheduling tuning soon.

 

[bazooka joe]

Yeah, just got back from a meet to go drive some fun roads here in PA, and no one behind me even commented on a smell. I can only faintly smell it. I'm surprised. Might be my tune? dunno.

It was coming up to boost faster than before, and holding the set boost all the way to redline though. The car is clearly faster overall at 4psi on the gauge than it used to be at 10psi. Will be re-scheduling tuning soon.

(cool)

The stink was something else, like driving thru turpentine.

haha!

 

[bazooka joe]

waiting to see new dyno #'s!!!

 

[6speed]

Scheduling the 2nd tuning attempt for next week today, presumably tuesday or wednesday

 

[6speed]

Tuning postponed longer than expected, thanks to a major shop project and then the tuner's annual vacation. I won't have numbers or higher boost till August 19th.

 

[subspeed6]

I keep reading this thread and it is like a roller-coaster ride. It has its ups and downs. Just when you think this car is ready and going to decimate something happens....

Mike, you have way more patience than me. I would have given up a long time ago and I probably would have set the car on fire.

 

[6speed]

Compared to my 99, my MSM has been a dream.

Virtually all of my problems have their roots in some mod I made or something I did by mistake, and I'm very much ok with that. I've only had 2 actual failures so far that don't fit that description, one was the wierd voltage problem, one was the left rear caliper seizing (and track duty could be fingered as the cause of that one if I wanted to press the issue)

Granted, every time I AM dealing with an issue, I find myself wishing I had traded my 99 in for a Boxster, or just gotten rid of the 99 instead and kept the 8. Even when it's working right, I get so tired from my commute that I don't really care much about when it's good.

But then, every so often, I take it out on some more enjoyable roads and really hammer on it, and it feels more worth it again. I'd still rather a DD I enjoy more consistently, but ... it IS a really potent car.


I've canceled tuning for now. I am tuned for 4-7psi, which is the most I'd be running on the track anyway, and it's rather fast at that pressure. I don't feel the need to turn up the boost any more before track days, and I am getting tired of missing out on track events this year. So I'm going to be working on a few other things, like a small splitter (no rear wing, so can't go crazy), underbody paneling, replacing the other rear caliper (preventive/pre-emptive), and seeing if I can get a hitch and a small tire trailer. I will pretty much need one if I'm going to ever do a track day at Mid Ohio, and I should have one anyway, even for the 3hr-away tracks.

 

[subspeed6]

It is funny because you mention that because I sold my MSM and picked up a '99.... (A 10th Anniversary one, but still a '99)

 

[6speed]

Well, since you haven't been screaming in frustration, tearing your hair (and the Miata's multiple engines) out...I guess you didn't buy someone else's problem like I did with my 99

 

[6speed]

Am I allowed to mention a new problem?

I think it's ECU related.

Basically, if I am cruising in gear in vacuum above 3,500rpm (my spool point), I can get positive boost with even part throttle, and with the throttle to the floor, I get the full 6psi in less than half a second. Spools nearly instantly the way I like it. However, if I am at full throttle, and I shift and immediately return to full throttle, even on a lazy shift, it takes 5-7 seconds of full throttle to get back up to 6psi. The gauge jumps to 0psi/0vacuum, and then agonizingly slowly climbs.

And I can't think of anything that would be crippling spool like that just because of a full throttle-shift-full throttle.

It doesn't do it if I am in vacuum, shift, and then go full throttle. It doesn't do it if I am at full throttle, shift, stay vacuum for ~5-7 seconds, then go full throttle. Since it's all mechanical, the only thing I can think of is that something in the ECU is retarding power, and thus flow, for a period of time after the shift, greatly slowing boost. Except that doesn't make a lick of sense either.

 

[subspeed6]

Well, since you haven't been screaming in frustration, tearing your hair (and the Miata's multiple engines) out...I guess you didn't buy someone else's problem like I did with my 99

No I didn't. I bought my friend's car and he was a mechanic. It is a little dirty, but runs like a champ!

 

[6speed]

I found a comparison last night about how fast my MSM is now, at 6psi without a clogged cat.

Leaving it in 6th gear and making 6psi at speeds where the aero drag means that high horsepower counts for more than high power to weight, I was holding dead even with a V8 Challenger who (thanks to the automatic transmission) almost certainly wasn't in it's highest gear. This was both on a long steep uphill, and the long downhill afterwards. (empty mountain highway)


I think i've narrowed the boost after shift problem (actually it's apparently boosting after throttle lift from boost to high vacuum, even if a shift isn't involved) to either the BOV or wastegate actuator, basically one of them is slow to close, venting boost or venting exhaust respectively. Will be testing today by using my GoPro mounted to the windshield to record my wastegate arm position (hood removed). If it responds fine, then I will be cleaning/testing the BOV.

 

[6speed]

It's the MBC. Apparently it doesn't work that well when it's turned all the way down, and closes off the wastegate line, retaining pressure there when off-throttle, which holds the wastegate open. It will slowly leak out, taking a bit before the wastegate is back under control again. I turned up the knob a few clicks off the bottom and boost behaves normally again.

 

[bazooka joe]

It's the MBC. Apparently it doesn't work that well when it's turned all the way down, and closes off the wastegate line, retaining pressure there when off-throttle, which holds the wastegate open. It will slowly leak out, taking a bit before the wastegate is back under control again. I turned up the knob a few clicks off the bottom and boost behaves normally again.

so it was turned all the way down and you were running 6lbs of boost?