I've got an extra squaretop here at the house if you decide to go that route...

 

Thanks, Joe. I think I'm going to bang on the bits I have before throwing random other parts at it for a bit, but I'll keep you in mind.

In other news, I found the boost leak:



That's one of the siliconeintakes.com "port system" thingeys, in the elbow that goes into the throttle body, supplying the boost source to use for the wastegate. I'm not sure if I screwed it up when I installed it, or if it just proved inadequate for the job. I think I'll replace it and weld a bung into the charge pipe below it that I made instead of using a port here.

So that explains the loss of spool, but I don't know if it explains the increased pinginess of the motor or not. A boost leak should make the turbo work harder, which should result in decreased VE, which should make it want *more* timing, not less. OTOH, it should also increase intake temps (which were somewhat evident on the dyno, although it's unclear how much of that was just due to lack of good airflow), which would tend to cause pinging.

--Ian

 

I'm guessing this, that's one hell of a boost leak. Do you still have logs with IATs from the 2560? How do they compare to the GTX?

 

When I had originally saw this before I thought to myself. "Hmm, I wouldn't do that." Interesting how it turned out you know for science

Hoping this solves your pinging issues! Keep going buddy.

 

The IATs from the dyno session are high, but not hugely out of line. Mostly they're in the low 60s (in C) at the end of the sweeps, with one at close to 70 where we did two back-to-back runs. It's maybe 5C higher than the logs from my dyno session with the 2560 in May last year. On the street the peak IATs are lower, but that's expected given the vastly increased airflow over the intercooler.

As for the silicone port thing, I vaguely recall having problems drilling one of the pipes, not being sure if it would seal properly, but putting it on the car because I wanted to start it and planning to replace it later. This may have been that part. Also, I suspect the port would work better in a straight coupler, rather than in a bend like this.

In any event, I ordered a replacement elbow and a weldable bung, and I'll fix it properly this weekend.

The other thing that we noticed broken on the dyno was an exhaust hanger:



I pulled it off and ran it over to a local fab shop to get it repaired at lunch. I have a nice Miller 211, but it wasn't worth buying stainless wire and a tank with a different gas mix just to weld this. It's an FM 3" muffler which has a lifetime warranty, but it was easier to just fix it than to deal with return & replacement.



--Ian

 

Well i guess the silicone pipe adapter that silicone intakes sells is off my radar now. I was trying to avoid the $90 TB elbow that fm sells. I know there are other locations for the IAT install and they are now back on the table.

 

Where ever you mount it, do it on a straight piece of coupler/pipe. Having it on that 90 degree angle is just, fail-prone.

 

btw: I know you said AIT's didn't skyrocket, but even still if the turbo was overspinning like crazy from the leak, it coulda been choking up due to exhaust back pressure

 

It's certainly possible. It's interesting, I haven't seen a boost leak before that was big enough to really alter the power output, yet small enough that the engine could still make any boost at all. I just hope I haven't damaged the turbo by trying to make boost with a big leak...

I should have it fixed this weekend, track day on April 17th at Thunderhill West. I'll have to see if I can find another dyno session in between.

--Ian

 

Sudden significant boost leaks and plugged exhausts, would show up in a turbine inlet-pressure reading.

 

Yeah, but unless one hooked up a TIP sensor and left it in full time, it's not all that useful. Boost leaks aren't hard to find once you know to look for them.

So, boost leak should now be fixed. I pulled out the adapter pipe I'd made, and added a 1/8" NPT bung to it:



(yes, I still suck at welding!)



The bung was longer than really necessary. I welded it so it was roughly at the same level as the one for the AIT, then realized there was about 3/8" of it sticking into the pipe. Doh. Much grinding later:



Installed:




So, that should fix the leak. I say should because I haven't tested it yet -- I put in new alignment bolts on Thursday night in preparation for aligning it on Friday, but for various reasons that appointment got cancelled. So right now the wheels are pointing in semi-random directions, and even going up and down the driveway it feels weird enough that I don't want to take it out for a boost test.

Track day coming up on April 17th. Before then I still need to reinstall the ducting & splash pan, fix the oil cooler mount, get it aligned, possibly retune if the boost leak fixes the top end... Yikes.

--Ian

 

Ian, Where will you be on the 17th?
Thunderhill by chance?

 

I'm running Thunderhill West with a small track day group.

--Ian

 

Very cool. I'll be up there on Friday helping to setup for the NASA event that weekend.

I'll come look for you after I'm finished. It'll be great to see your car in person!

 

Yeah, come on by. I'll probably be the only Miata in a sea of BMWs and Porsches.

So no boost leak testing yet, but I did at least reinforce the oil cooler mount. A month or so ago I learned that the standard Setrab/Mocal oil coolers don't give you four mounts just to be convenient: you really need to use all four of them because there isn't much structural rigidity to the cooler itself, and if you don't then it has a tendency to turn banana-shaped and leak.

The FM oil cooler mount that I'm using only attaches the lower brackets, so I reinforced it by fitting spacers between the upper and lower ones and using long bolts.




--Ian

 

Mount looks good, I was going to do the exact same thing with mine. Good to see independent confirmation How much airflow does it get in that location? I'm wondering how it all goes together with the undertray, I need to stick my nose under your car next time I see you. Still rocking the PS?

 

I dunno how much flow it gets, but it seemed to keep the oil temps down a few years ago when I first put it in. At the moment I don't have a working oil temp gauge installed -- that's one more thing I'd really like to get done before the track day.

Must do:
- Validate boost leak fix and investigate happiness with current tune
- Align the car (happening today)
- Reinstall splash pan & other rad ducting

Would like to do, but not sure if I have time:
- Install oil temp gauge
- Reinstall DL1 datalogger
- Make parking brake work again
- Hook up EGT sender to MS3 so I can log it

As for the belly pan, the brackets for the oil cooler go down about half an inch below where it would be factory. It bends around them, though. Definitely not optimal, but it works.

And yes, I still have the PS. That's not coming out.

--Ian

 

Alignment is done.


With half a tank of gas and without me in it the car weighed 2408 pounds, 51.9% front. It'd be under 2400 if I'd taken out the various pieces pieces of crap that were in the passenger seat.

--Ian

 

Our cars are twins:

 

Yeah, but your paint is in MUCH better condition than mine.

--Ian