^Sad Panda... : / Good luck with finding the culprit Pearl.

 

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 found the problem. $150 isn't too bad. Is your ignition still failing? I thought you fixed that.

 

Yes, but not for the first 1,000-1,500 miles of driving on this cat. Apparently it was compounded by my fuel pump upgrade, which apparently increased my fuel pressure enough that it richened me up across the board into the 9.0-9.8 AFR range under boost. Misfires plus running that rich is a death sentance for any cat. Not really surprising in the end.

I went out with some guys from here this weekend, and the car pulls as hard at 4psi as it used to at 10, only now it holds it to redline so it is significantly faster. At 6psi, the car is so much faster than before, and I still have 6 more psi of safe room to go on engine strength.

I may already be starting to overwhelm the clutch though. I have an upgraded one that is supposed to hold up to 315wtq, but twice over the weekend it started slipping in 2nd gear at full throttle on a steep uphill.

 

That car has to be a blast to drive. Are you running a stock diff? How is traction?

 

I have a 3.63 rear gear instead of a 4.1 rear gear, but the rear is otherwise stock. The MSM axles can handle around 450wtq, and the diff is thought to handle at least 600wtq, but no one knows for sure since anyone that gets that much power has already replaced it. Breaking diffs isn't a problem for us in general. Even the transmission is good for about 400tq/hp.

As far as 'how traction is', that's a mixed answer. I have 4 sets of wheels/tires. On my track tires saturday, I never got them to break free. However, I do also have a set of 480 treadwear 185 width all seasons, that are easy to break free even at lower power levels, and quite enjoyable to do so. My main commuting set will probably break free easier now, but only when i want. I haven't tried the winters, and I won't at this point.

 

So the Maita survived the Merc I take it? I bet that was a really butt pucker moment.

 

Yeah, no damage, but I was shaking a bit. If he hadn't, or his stablity control hadn't kicked in to kill the rear's rotation that was starting, I have no doubt that it would be been extremely messy, and I probably wouldn't have survived.

 

That's a whole lot of fail on the other drivers fault. I'm guessing it was a blind corner.

 

It looks like Mazda thought ahead in that regard.

 

Glad to know you made it through ok. Did you have to change your shorts afterwards?

 

Well, on the surface, the car is hugely over-built for a +32hp gain from the factory turbo stuff. Extra stiffening, stronger drivetrain in several areas, etc... The going theory is that the engineers actually built the car as a 200whp (~230hp) car, and someone else complained that the outgoing MSM would be trouncing the incoming 2006 NC handily, so it was fitted with a hugely restrictive intake and downpipe and a patched NB ECU was used instead of something more capable. So it was released with the same peak power as the incoming NC, and all you have to do is fix the restrictions for ~200whp, though you still have to deal with a retarded ECU until you fix that too.

So yeah, Mazda thought ahead, but the left hand thought farther than the right, and the right was thinking ahead about why it shouldn't be as far ahead as the left thinks it should.

Or something.

It was a fast left/right/left/right/left/right/etc... slalomish section, where some of the changes were blind, like that one, and camber was changing on every switch. Just someone doing something stupid in the heat of the moment, highlighting why I prefer to avoid large road-going meets. Large parking lot meets too, actually.

 

Just a bit.

 

i will tell you guys that riwwps car is no joke. that little bastard hauls ***

 

I would venture to guess that little car has surprised a few people in it's time. I am really curious to see the new Miata. I hope they are going with the smaller displacement turbo and lower weight.

 

As Fat Bastard from Austin Powers would say 'I think I left a rosebud in there for ya. Oh yeah! I did!'.

 

Yes, yes it has

 

Awesome! Glad you sussed out the problem, and it's back to holding boost for you. WANT TO SEE NUMBERSSSSSS..... get some more graphs in here...!!!

 

I plan on starting the Izuzu V6 swap in October, so graphs of the final results should be available no later than the end of August.

 

Excellent.


Oh, and where is the sign up sheet for rides?

 

In my garage. Registration requires the title and key transfer of a certain CWP R3

 

You don't want it, I've doubled the miles on it... it has almost 18,000 miles on it now!!! I know... the horror...

 

That will not stop him.

 

Tuning is postponed a while. My AFRs are stable at low boost, and I've got enough other things to pay for before i get to Watkin's Glen. Besides last night I discovered that uh, well, lets just say a V8 Challenger was surprised to find that he wasn't leaving the mere Miata behind.

I did find a new problem though. Either wastegate or BOV problem I think. After a sharp high vacuum throttle let-off (like a high RPM shift, high RPM lift, then back planting on the gas), I have trouble making boost again for 4-6 seconds. If I let off slowly, I have full boost right back, and if I am only very briefly at full boost, then I seem to get full boost right back.

The only two things I can think of that would cause this is either
A) The wastegate is sticking open, and only slowly re-closing, so it's just venting lots of gas past the turbine until it closes enough to start working where it should
or B) The BOV is popping open from the throttle change, but then taking a while to close.

I suspect it's the wastegate, since the BOV actuation doesn't really care how much air/exhaust I'm flowing when it dumps, but the wastegate does. I'm going to pull the hood today, mount the GoPro to the windshield where it can see the wastegate arm, and take it for a quick test. If it seems to be working fine, then I'll test the BOV next. Between the two, I'd far rather it be the BOV, but...it's probably not.

 

That problem ^ was just having the MBC all the way down. Pinches off the bleed holes or something. Turning it back up just off the bottom made that problem disappear.



This past weekend I pulled the turbo and upgraded the studs to iconel. No pictures because well, it's just the turbo out, then in again. One more thing I won't have to worry about breaking on track.

Also installed the AEM wideband. It is confirming that I'm still richer than I should be (10s). I suspect I may have pinched the vacuum line to the gauge, so I'll have to be re-running that i think. At first, I was in boost and the gauge was still reading 0, then it finally lurched up to 5psi. That might have been the pressure in the line un-kinking something. Boost is showing 5.7psi at full throttle, but not sure if i can trust that yet if the signal line had a problem with it.