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Finally got around do doing some autotuning yesterday. Dead easy, and really improved how the car ran.
Today I did some searching for AFR target maps, and picked one that looked like it would suit my needs. Loaded it up, and autotuned. Holy cow- major improvement. I think I finally realized the benefits of deleting the stock airflow meter.
I've had my SC bypass zip-tied open, because I haven't replaced the stock 1.6L injectors with the FF610's yet. However, I still have the rising rate fuel pressure regulator installed, so I figured why not give it a whirl. Cut the bypass zip tie and did some more autotuning in boost- wow, huge improvement in power. I'm still fine tuning idle, but I'm already overjoyed at the improvement in the car.
Next step- install FF610 injectors and re-tune. Also need to get a roll bar in this thing.
Signed up for my first event, SCCA Track Night in America at Atlanta Motorsports Park. The event was last night. Chronology:
- came down with a vicious cold on Monday
- drove up to the track yesterday afternoon in a biblical summer rainstorm. My no-A/C car reached approximately 150 degrees interior.
- got to the security gate at the track. As I'm pulling up, I hear a violent flapping noise from the engine bay, and the car stalls. Won't crank. I get out, push the car to the side, and wave through the Viper and new Vette that were behind me. My first point-by.
- spend the next hour in the now-blazing sun, working over a hot engine, unwinding my shredded supercharger belt from the crank pulley. Lose about 10 pounds.
- wire the supercharger bypass open, drive home.
Lessons learned: When someone is sending you signs, listen to the signs. Always carry a spare supercharger belt. Or get rid of the damned supercharger. I considered running the event anyway, but a non-rotating supercharger makes about the worst air intake in the world.
Finally got around to making a variable TPS. I had scrounged the metal mounting plate from a junkyard car, and got the Wells 201 off of Amazon. Mounted it up:
Hooked it all up, jumpered the VTPS in my MSPNP2, and stole the acceleration enrichment settings from the 94-95 basemap. Took it for a drive tonight; TPSdot rocks. The hesitation when stepping on the gas pedal is gone, and the transition in and out of overrun cut is much, much smoother. The only thing is that if I'm already rolling and I get on the throttle hard, the engine stumbles. Looking at the log, when TPSdot cranks up, it goes way too rich- like in the 9's. I need to figure out how to tune it.
On another note, I figured out Virtual Dyno. Did a pull tonight, looks like I'm running about 137hp and 117 ft-lbs. I'm not terribly disappointed with this considering I haven't touched the timing map yet. It feels faster than that- possibly because of the smooth torque curve. It pulls pretty nicely from 3500rpm up.
Last edited by Schroedinger; 06-26-2017 at 01:52 PM.
So it's been an interesting week. On a lark I listed the supercharger kit for sale locally, and within a day or two I got a good offer for not only the SC but the entire 1.6 motor. Buyer is supposed to formally commit tonight. Looks like I'm headed to Swapville.
In other news, I learned that it's possible to haul a Miata motor in the back of a minivan without spontaneously sprouting a vagina.
I had been thinking about swapping in a VVT motor. Then I was thinking that I'd probably do a coolant re-route. Then I was thinking that I would need a different head gasket to do it right. Then I was thinking that while the head was off, I'd replace valve springs and seals. But while I'm in there, why not forged rods? And onward down the slippery slope.
Then I found this on Craigslist, a running BP4W for $200. I called the guy, he seemed legit, and I figured it was worth a shot as it's probably worth at least that in parts alone. Here's what I know about it:
- The guy and his wife are retired, and were really cool. The guy seems pretty handy and had a workshop with an engine lift, I think he likes to work on bikes. The car it came from is single owner '99 NB with 132k that they still baby and drive all the time. They gave me a bunch of service records with the motor, which include a TB/WP, seals, and an oil pump replacement (?) in the last 10k miles.
- The motor was replaced by a mechanic in May 2017. Sounds like it lost compression; still ran, no rod knock or anything, but was significantly down on power.
- To the best of their knowledge, it had never overheated or been run dry of oil. That oil pump replacement has me wondering though...
I'm gathering up my plans for the rebuild/swap. I have to pull my 1.6L this weekend, so I'll have a non-running car until I get it figured out. First I'm going to tear down the motor to have a look at what's going on in there; I'm not sure if the compression loss is piston rings or valves/seals. Depending on what I find, I may do one of two things:
- if it's not bad (top end only), I may do a more-or-less stock rebuild and get it back in the car quick.
- if it needs more than that (top and bottom), I may find another running VVT motor that I can drop in without opening. Then I'll take my time with this one and do a bad-azz, no expense spared turbo build over time.
Last edited by Schroedinger; 07-18-2017 at 02:46 PM.
The owners of this motor lived in Key West for 3 years, and the motor looks like it. Lots of surface rust and rusty bolts.
I started messing around with it. Pulled off the valve cover- pleasantly surprised. Everything looks well-oiled, no signs of unusual wear or corrosion.
So I pulled the spark plugs. Cylinders #1 and 4 looked normal. Cylinders #2 and 3 were filled with watery coolant. Oddly, the coolant was both above the plugs and below them in the combustion chamber. I' assuming it's a head gasket issue.
I proceeded to do a leakdown test, because I wanted to see if the valves and pistons were sealing correctly (independent of the head gasket issue). It's the first time I've done a leakdown, so I followed the instructions:
- Exhaust unobstructed, throttle blocked open. Oil dipstick pulled.
- cylinder being tested at TDC on compression stroke (all valves closed)
The motor was obviously cold, but from everything I've read a cold test is a worst-case test because everything would seal better at operating temp.
Here's where it gets weird. All cylinders were very good in leakdown- around 6-8% on all cylinders, on a stone cold motor. Not believing the result, I intentionally tested a cylinder at TDC of the exhaust stroke, with the exhaust valves open. >60% leakdown; it appears that the tool is working correctly.
Here's where I need help from anyone who cares to answer. Tell me if the following statements are correct or incorrect:
- I didn't make some newb mistake with the leakdown test, and the good results are meaningful.
- The head gasket leak is small enough that it's beneath the sensitivity of the leakdown test, or was an intermittent problem that happens when the engine heats up.
- The valves and piston rings are indeed sealing correctly.
- If I pull the head and the mating head/block surfaces are still within flatness spec, it may only require a head gasket to get this motor back to good health.
Thanks in advance to anyone who can provide guidance.
Last edited by Schroedinger; 07-20-2017 at 03:02 PM.
So I've had these used Flow Force 610cc injectors sitting around for a few months. I've read about people having idle and tuning issues with big injectors and small motors, so I was a little reluctant to put them in. I thought the AFPR was working pretty decent, and I wasn't in a big rush. But the last few months I've gotten more comfortable with tuning my MS2, and I've gotten better at reading data logs. I realized that with the AFPR, my AFR's were pretty unpredictable in boost. I also realized that at full boost (7psi), even with the AFPR my stock 1.6L injectors were at 90%+ pulsewidth trying to keep up. I realized it's time to install the FF's, and ordered the necessary seals and o-rings.
Put them in the car tonight. Easy job.
Changed Req Fuel, dead time and voltage compensation per the instructions on the website. Crossed my fingers and started it up.
Result? Perfect idle right away, AFR was pretty much dead on. Drove around and autotuned for 30 minutes, no issues at all. A few more tweaks in the idle cells and the tune is pretty much perfect. I'll work on my enrichments tomorrow, but the car's running great with no AE at all.
One thing I learned about tuning idle. If you watch the VE map at idle and you see any oscillation, set all the cells in that region to the same VE value. Oscillation goes away, and anything remaining you can dial out with idle PID settings.
This build thread is becoming one of those movies where you have two intersecting storylines. In story #2 (the '99 1.8 motor), I was encouraged by the good results in the leakdown test. The previous owner complained of the motor stuttering and losing power. As I've been taking things apart, I noticed this:
I think I've solved the mystery of the poorly running motor- the crank nose bolt came loose, and all the bits are worn out. The timing gear probably has 10-15 degrees of wiggle on the crankshaft. The pulley boss is worn eccentrically and the pulley wobbles. Most unfortunate is that the keyway on the crank nose is pretty worn. If I was just trying to get this thing back on the road, it would probably be a good candidate for the Loctite fix. However, I was going to take it all down and build it back with forged rods and new bearings, so I might as well just go ahead and replace the crank.
On a positive note, now that I know why the motor was running like poo, it gives me hope that the head is probably fine. Going to pull it tonight to inspect.
I can't seem to track down a decent BP crank for less than $200. But I found another orphan motor on CL for $100. This one is a '95 with 100k on it; it was over-revved and the valve springs are shot, but supposedly the bottom end is solid. So depending how good the bottom is, I may just run the '95 bottom end and the '99 top, or I may transplant the '95 crank into the '99 block. My garage is going to be full of motor parts, and my wife is going to kick my ***.
A year and a half of work, only to end up back where I started- with a stock 1.6L motor.
Found a buyer for the Jackson M45 supercharger kit, and sold it for the same amount that I bought it for.
Not to fear, power is on the way. I now have a grand total of $300 invested in two 1.8L motors. The subjects:
On the left, a 1995 motor with 100k that I bought from a mechanic. Supposedly has a good bottom end (with the lower 8.8 compression pistons) and a bad valvetrain. On the right, a 2000 motor with 135k and a good head and VICS manifold, and a trashed keyway on the crankshaft.
This week I pull them apart. If the 2000 head and the 95 bottom check out OK and have good flat surfaces, I'm going to get a head gasket and some ARP studs, slam them together and do the transplant. Then an MKTURBO setup from Lars, and I should be sitting at 220 whp. I'll then take my time building the 2000 bottom end with forged stuff for future shenanigans.
The head is off of the '95 motor. In case any of you want to see what happens when you rev a stock motor to 9k:
A bunch of bent valves, mostly exhaust, some intake. As expected from what the PO told me. No worries, I knew the head had issues. Now onto the bottom end:
... and after 5 minutes with a brass brush:
Things are looking really good down there. The pistons and bores look great, no scoring at all and the cross-hatching looks good. Checked flatness of the deck with a precision straightedge and feeler gauges (all the tools from my other hobby as a luthier are coming in handy). I can't get a 0.001 feeler gauge under the straightedge anywhere, the deck is almost perfectly flat.
Previous owner said it was making good oil pressure when it was pulled, so the oil pump should be in good order. I'm hoping that what I find in the 2000 head looks this good; if so, I'm not going to take things down any further. Get it together and get it in the car.
05-26-2017, 05:51 PM
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