gesso

iTrader: (1)

Are you going with DnF on Wednesday?

codrus

To Thunderhill? No, it's a group called PDC, Friday April 17.

Once I get the car properly sorted I intend to start doing track days more frequently again, but it needs to be reliable first.

--Ian

codrus

So, having fixed the boost leak, I went out to test the car. I had three primary goals:

1) determine if this fixes the spool.
2) determine if this fixes the pinginess of the motor.
3) determine if this fixes the lack of expected high-end power.

The answer for #1 is a definitive yes. For #2, it appears that pinginess at the torque peak hasn't changed, but that there seems to be room for more timing at the top end. #3 is hard to do just from the street, but running autotune wasn't adding much if any VE up top. Of course, if there's room for more timing then maybe it'll make more even without more fuel.

As for the spool, here's a datalog from the dyno:



It's got a boost target of 230 kpa, and it's cutting in the EBC around 215. The initial duty table is wrong, so it sticks in a value that's too low, which is why the boost ramp curve noses over so hard there, and it takes a long time for the PID algorithm to get it up to 230. To eliminate that, I'm measuring the spool to 215. On the dyno, this took 4125 RPM.

Here's a datalog from tonight, also a 5th gear run with a 230 kpa boost target. It's got the same wrong initial duty table value, so it does the same stupid nose-over at 215 kpa. Never mind, here it's hitting 215 kpa at 3665, 450 RPM sooner.



Part of this is that the DynaPack dyno was controlling the RPM rise a particular rate, which appears to be a bit faster than the car was doing in 5th on the road. Still, the difference in responsiveness of the car before/after fixing the leak is enormous.

So the derivative question I was hoping to answer is whether I should try to get it back on the dyno before the PDC day in just over a week. I think the answer is yes -- I'd really like to see if I can raise the timing at the top end, not necessarily for power but to try to keep EGTs under control while wringing it out at the track.

--Ian

codrus

Something else came up, I noticed it was making a weird scraping noise at idle which made me worry about the turbo bearing. Fortunately it's coming from the front of the engine, not the turbo. I pulled the belts off and ran it this evening, thinking it might be the water pump bearing (I reused the 10K mile water pump), but no it's still there with no belts. Looking through the access port on the lower timing belt cover, though, I could see the timing belt oscillating in time with the scrape. It's about 150 RPM at a ~ 1K RPM idle, so 1/6th to 1/7th crank speed.

So I guess I need to retension the timing belt this weekend. Ah well, that's fairly simple at least.

--Ian

codrus

Probably not time to put this in before the track day -- a shame.



--Ian

codrus

So I grabbed an hour on a dynojet this morning to see if it would take more timing at the top. Unfortunately, the answer is no. It's not at MBT yet, there's more power available up there, but it pings. Run 1 is the same map as on the dynapack at BlackTrax, run 2 is +2 degrees and it's adding power. Run 2 was ping-free, but once the car heat soaked, subsequent runs at that same advance level started pinging, so I had to take it back out.

The last run is at 180 kpa, which is where I plan to run it at Thunderhill next Friday.



So it appears that this motor is just more pingey than my previous one, which is frustrating. I don't know why, although I have a few theories:

- Maybe the "9.0:1" Supertech pistons I got from FM for the old motor were actually 8.6. I dunno, I can't find them, so I don't have any way to check.

- There was still a small amount of screw-head damage visible on the head in the combustion chamber for #3. It's in the quench area, which in theory shouldn't affect it, but...

- The head was definitely decked, so that's presumably increasing the compression ratio by a bit. I don't know how much.

- I also don't know how much the block was decked on the old motor vs the new one, so that might be another factor.

So in retrospect I probably should've put 8.6 pistons in this motor. Ah well, it's really too late for that now. I guess I'll probably have to compensate with more octane -- straight 100 or perhaps E85. 100 isn't cheap, but the car doesn't exactly get a lot of miles on it. I've got the ID1000s for E85, but the problem is you can't get it at the track, and I don't really want to haul a 55 gallon drum of fuel to the track with me...

--Ian

18psi

iTrader: (76)

e85 is so much cheaper than 100 that even investing in a drum would likely cost you less.

williams805

iTrader: (2)

Yeah but how long would a 55 gal drum last vs shelf life? Maybe if you had a buddy to go in on it with you.

codrus

It may be cheaper, but it's a PITA. The nearest E85 is a lot further from my house than the nearest 100 station, and with only a a 12 gallon tank in the Miata...

As for the drum, there are hazmat regulations about transporting significant quantities of gasoline, I'm told the limit is around 25 gallons. I dunno what the CHP does if they pull you over with more than that, but I suspect it may be more than just a slap on the wrist.

So does anyone know what it takes to run E85 with the MS3? I've got ID1000s and a walbro -- just add a flex fuel sensor? Are the stock fuel lines big enough?

--Ian

codrus

The drum would be for track days. With the 2560 and a 12 gallon tank I would get about an 60-75 minutes before I needed to refuel it. E85 and 350 at the wheels is going to, what, 45 minutes per 12 gallons? Doing a track weekend with 2 hours per day that's 50+ gallons required.

The nearest E85 station to Sears Point is about 30 miles away in Fairfield. The nearest one to Laguna in San Jose (60 miles) and the nearest one to Thunderhill is in Sacramento.

One other idea I've thought of is to get one of those in-bed fuel tanks that I see in lots of pickups. Anyone know if those are rated for E85, or are they diesel-only?

--Ian

HHammerly

iTrader: (3)

So does anyone know what it takes to run E85 with the MS3? I've got ID1000s and a walbro -- just add a flex fuel sensor? Are the stock fuel lines big enough?

--Ian[/QUOTE]
The way to go is with a fuel composition sensor, the MS3 will blend your fuel and timing maps according to whatever you have in the tank, i think that this is the only way to go with E85 and installed the sensor and everithing but am not getting a clean signal to the MS3 so i dont have a tune for it yet.

aidandj

iTrader: (5)

That would be ideal. My buddy used to have one for gas, so its just a matter of getting the right one. You can get them in huge sizes too, like 100+gallons.

curly

iTrader: (25)

I feel like you should solve your pinging issue on pump gas, then start messing with e85.

Your major issue is California gas. Your second big issue is a damaged head. Any pitting in the combustion chamber is going to cause it to ping easier.

Get your cal-gas ignition, boost, and fuel map finalized for a good base map, then move on to e85 for safety and more timing.

codrus

I've never used straight pump gas in this car with the turbo -- it's gotten a mix of 100 and 91 since I first installed it. With the approx 2500 miles that the cars gets per year these days, running the 50/50 mix is costing me all of $300 extra a year, which IMHO is cheap insurance. The old motor was practically ping-proof on that fuel, when I first put in the MS3 and tried to transfer my Hydra map, I was 10 degrees past MBT at 200 kpa and it still didn't ping. The new motor pings a lot earlier, and I don't really know why.

So if I substitute my minimum intended 50/50 mix for "cal-gas" in your statement, then I think I'm pretty much there.

Here's a zoomed-in picture of the head after the machine shop cleaned it up (I mis-remembered which was the damaged cylinder when I said #3 above, it's actually #4):



The opinion of the machinist and of other folks I asked was that being in the quench area like this, the remaining damage shouldn't make much difference. I dunno, maybe it does? I guess I could pull the head back off and try again to fix it. Can this sort of thing be welded? That would presumably involve taking yet another pass over the head with the surfacing tool, though.

--Ian

JasonC SBB

Does it ping on one cylinder of all of them?

patsmx5

iTrader: (16)

First question, is the ping audible? Are you using det cans?

See the edge just inside the red circle.



Did you leave that sharp edge on every cylinder? If so, that could absolutely cause detonation.

Second question, what pistons are in your engine? What comp? Pics of them?

Third question, does adding fuel stop the detonation? Have you calibrated your wideband? Is the sensor more than 2 years old?

Fourth, does your car have PCV hooked up or the crankcase vent in a way that could push oil into the engine?

Import Al

iTrader: (5)

Well hello, sir. Good luck throwing down triple my Fit's WHP next time, It was nice meeting you and rekindling my urge to acquire Miatae.

codrus

Ping is audible to the dyno tech and to TK. I have a hard time hearing/distinguishing it myself, but that may well be due to my familial hearing loss. The knock sensor sees spikes when it pings, but I haven't got it reliably tuned to distinguish knock from other ambient noise yet. We used detcans when tuning at Blacktrax on their DynaPack a couple weeks ago (see earlier in the thread), but they weren't available for the most recent run on the DynoJet at Synergy.

That's how the head came back from the machine shop -- all I did before bolting it on was clean it. I certainly didn't go at it with a grinder myself.

The pistons are Supertechs, 9.0:1. Lots of pics earlier in the thread.

Adding fuel does not appear to stop the detonation, although I haven't tried going richer than about 10.5:1 (AFR target is 11:1 for the 230 row). The wideband is an LC-2, I bought it about a year ago, and recalibrated the sensor when I put the car together in February.

The PCV is hooked up in the traditional fashion, the cam breather is hooked to the intake through a catch can. This is no different from the previous motor, however, so while it may be less than ideal, I don't think it's the main cause of the difference.

--Ian

codrus

Hey there! So did the extra 10 hp they found make a difference?

--Ian

codrus

The ping does not appear to be limited to a specific cylinder. This pull, for example, showed it on #2 and #3:



--Ian