The ups and downs of a 2.7L Turbo

[cleanasse30]

So interestingly enough, I did the injector dead time test today using the method above by switching from 1 squirt simultaneous to 2 squirts simultaneous and checking if the AFRs remained constant. I wasn't able to get the AFRs to remain exactly the same(.3ish off), but the best dead time turned out to be 1.13ms as I was running before. Since that doesn't seem to match the given dead time value that I've found online for Bosch 55# injectors, I think the injectors I have might be modified. This also leads me to believe that I had asked the PO for the dead times and entered them in when I got it running for the first time.

Anyways, I adjusted the timing and AFR table a bit and did some more Tune Analyzing tonight. By the end of the drive the car felt like it was running really well. Once I get the VE table a little more dialed in I'll start throwing some more timing at it and take some logs to throw into Virtual Dyno.

Here are a few of my tables right now.

[cleanasse30]

The last log I took to throw into virtual dyno the on-ramp was slightly uphill, so I think my power values were a little lower than they should've been. I took another 3rd gear pull log today, this time over a floating bridge so I know the road is flat. The difference between this run and the last is that I added a degree of timing in boost above 4k RPM iirc and got my AFRs more dialed into the mid 11s. Results were 314hp and 330tq, pretty darn happy with that!



I also realized that I have my wastegate hooked up slightly wrong. My manifold pressure reference is post throttle, and I think its supposed to be pre-throttle. To fix this I plan to take the compressor cover off my turbo, drill and tap it for a nipple fitting and then add an electronic boost control solenoid since my MegaSquirt has the added drivers. The reason I want to go with electronic boost control instead of a manual is that one side effect of manual boost controllers is partial throttle full boost. PTFB affects drivability in a negative way imo. For instance coming out of a corner and applying the throttle gradually would cause a boost spike and would make power delivery less linear through the rpm range. For a rwd car that struggles with grip that sounds like a recipe to spin out exiting corners.

For now the car feels pretty good, and the tune seems relatively safe, so I might just leave it as is for now until I get the electronic boost control hooked up.

[CorvallisBMW]

EBC is definitely the way to go, good choice. But your manifold pressure pickup is actually correct if it's post-throttle. Moving it pre-throttle would give incorrect readings, because the motor isn't experiencing pre-throttle pressures, it's experiencing post-throttle pressures, since your intake/combustion chambers are post-throttle.

[squidmaster]

^ yes, keep the map post-TB.

numbers look pretty solid. Can you hook your WB up to log, too? Will definitely help your tuning

edit: wait, is the dotted line AFR? You can definitely tune leaner than 9.5-9.8. Aim for 11-11.8. Play around with the settings until you find the happy point for your engine.

[cleanasse30]

EBC is definitely the way to go, good choice. But you're manifold pressure pickup is actually correct if it's post-throttle. Moving it pre-throttle would give incorrect readings, because the motor isn't experiencing pre-throttle pressures, it's experiencing post-throttle pressures, since your intake/combustion chambers are post-throttle.

That makes sense, but it does make the WG spring less accurate since there is a drop in pressure. My 7lb spring gives me about 10lbs of boost hooked up post-TB. I think it might be easier to tune the EBC if it references from the compressor housing since a 7lb spring would give 7lb boost. I'll play around with them and see which works better once I get the EBC hooked up.

^ yes, keep the map post-TB.

numbers look pretty solid. Can you hook your WB up to log, too? Will definitely help your tuning

edit: wait, is the dotted line AFR? You can definitely tune leaner than 9.5-9.8. Aim for 11-11.8. Play around with the settings until you find the happy point for your engine.

The solid line is AFR, dotted is supposed to be boost but Virtual Dyno doesn't pull boost out of the log properly for some reason...

For whatever reason with the way the waste gate is setup right now I'm seeing boost creep above 5k or so. It initially hits at 10psi and holds for a bit and then creeps up to 13 or so by redline which is why there is the spike in power at the end of the last graph. I'm hoping the EBC can eliminate this issue down the road, I just hope my waste gate isn't too small.

[squidmaster]

VD shows me boost in a dotted line as well. I don't know why I had them backwards. I didn't even noticed the dotted plot at first. It was almost midnight, please forgive my mixup.

Anyway, AFR is okay, especially if it'll be leaner once you get that boost creep taken care of.

Is your WG mechanically controlled, or electronically?

[cleanasse30]

VD shows me boost in a dotted line as well. I don't know why I had them backwards. I didn't even noticed the dotted plot at first. It was almost midnight, please forgive my mixup.

Anyway, AFR is okay, especially if it'll be leaner once you get that boost creep taken care of.

Is your WG mechanically controlled, or electronically?

Haha, yeah no worries. Currently my WG is running only on spring pressure, I plan to add EBC in the near future and tune it for 13-14psi which should fall right in the middle of the efficiency island of the turbo.

I'm happy with the AFR for now because of the boost creep, but I'll keep working on getting it closer to 11.5-11.8 when I have EBC.

[donaldvw]

wow, this is some good stuff here. I need to pick your brain sometime.
if you don't mind!

[cleanasse30]

wow, this is some good stuff here. I need to pick your brain sometime.
if you don't mind!

Thanks! Happy to help, just let me know.

[cleanasse30]

Haven't driven the car in the past week, but I have been making some progress. I ordered a boost control solenoid which arrived yesterday. It doesn't come with a pigtail so I went to the local pick-n-pull and grabbed a couple pigtails from GM washer bottle pumps. I chose this solenoid since it is a OEM part which should have good reliability and has a plug for easy disconnect should it ever need replacing.



My friend who has a soldering iron should be able to help me solder the wires into the connector for the Mega Squirt this week. Once its wired up I will start tuning the waste gate duty cycle map and see if I can get rid of the boost creep.

Last week at a local meet a member showed me his clutch stop mod, which I had never heard of for these cars. I looked into it and ended up making my own out of a M10x1.5 40mm bolt and a plastic stick-on furniture foot. Adjusting the clutch stop to stop the clutch pedal soon after it disengages the clutch makes the grabby clutch so much more manageable. I would suggest this mod to anyone with a heavier than stock clutch, super easy and costs less than $5. I'll grab a picture sooner or later.

[cleanasse30]

Last week my buddy helped me wire up my boost control solenoid. In case anyone is wondering since I couldn't find documentation on wiring up the boost control solenoid to the whodwho megasquirt, the ECU acts as a switched ground. On the DB15 connector, the boost control pin is the middle pin on the row with 7 pins. We found a wire I believed was a ign switched 12v, measured the voltage with a multi-meter and then tapped it for the power wire to the solenoid. Once we had the power wire figured out we then ran another wire to the DB15 connector for the switched ground. Since I haven't soldered much before, my buddy showed me a tip for soldering wires into cups on the DB15 connector. Preload the wire with solder, insert it into the cup and then heat the wire with the iron to melt the solder into the cup.

Here is the holder my buddy rigged up:


Getting things ready to solder:


Once we had it soldered and wired up, we had to figure out what pin on the ECU it was wired to. luckily we found the pin on the second try in test mode, it turned out to be PA0.



Unfortunately the fittings to run the vacuum lines to the wastegate were at my parents house so we couldn't get the boost control hooked up that night. Last night it was mostly dry out so I ran and got the fittings and plumbed the solenoid based on a diagram I found on the interwebs.



THIS WAS THE WRONG ROUTING!!! Luckily I had enabled boost cut, so I didn't blow the engine, but this routing was holding the wastegate closed, not good.

After some driving around and trouble shooting we figured out the routing for the solenoid based on the TurboSmart wastegate routing diagram below:



This routing does work for some applications, but we found out through testing that because my wastegate is fairly small for this turbo (remember the boost creep I was having) this setup doesn't work well and causes boost spikes. The reasoning that this happens is that this setup bleeds a ratio of pressure between the top and bottom of the diaphragm. Because I only want to run slightly above spring pressure, portioning the pressure doesn't allow enough control at low pressures. This means I need to run a bleeding solenoid setup as shown below:



This setup will supply both sides of the diaphragm with the same boost pressure unless the solenoid is activated to bleed of pressure the the atmosphere through the open port. It was getting late last night so I haven't set this up yet, but hopefully this weekend I'll have a chance to try it out.

[CorvallisBMW]

Awesome write-up, I'll have to refer back to it when I go EBC this spring :up:

[cleanasse30]

Last night I re-plumbed the boost control, which involved drilling and tapping the compressor cover for a boost only reference. When I took the filter off the compressor I noticed a ton of black dirt in the intake pipe and compressor housing leading into the turbo. I think this is mostly from my oil catch can since I have it plumbed into the intake.





I cleaned as much of the dirt off as I could with a can of Brakecleen.

Here is the turbo without the compressor cover on. First time seeing the Borg Warner extended tip technology in person. The turbo feels healthy, no shaft play whatsoever and the wheel spins freely.



Once the cover was off I checked my oil drain fittings since there was quite a lot of oil dirt on the fittings. They were all loose... I removed teh oil drain line from the turbo to make sure the oil was draining to the pan, which is was as far as I could tell. I reinstalled the drain and tightened all the oil drain fittings, hopefully that will fix the leaks.

Just the tip...


Once I had finished the oil drain it was on to drilling the compressor cover. I chose to place it close to the outlet since I thought it would be easier to clean up the metal shavings. To avoid getting metal shavings in the small crevasses I shoved a paper towel in the outlet, past where I was going to drill.



I started by drilling a 1/8" pilot hole. When drilling into metal, use oil to cool down the drill bit and operate the drill on a slower speed. Especially on hard metal, you do not want to spin the drill bit as fast as possible since doing so will heat up the drill bit and dull the cutting edge.



An 1/8" NPT tap calls for an 11/32" bit, which I didn't have in my drill kit. If you are going to do this go buy one ahead of time. The fitting I'm using is a 1/8" NPT to 3/16" barb brass fitting, both the tap and fitting were about $10 on amazon.



I don't have a tap handle, and when I saw it was $20 at HD I said fuck that. I don't tap things too often so I'm just going to use an adjustable wrench. The only tricky part is getting it started on axis with the drilled hole. If you take your time its not too hard.



Since NPT taps are tapered and I didn't want my fitting to protrude into the path of the air in the compressor housing I tapped a few turns, and then threaded the fitting to check depth and repeated until it looked like this:



After I was done tapping the hole, I wrapped the fitting in teflon tape and installed it into the compressor cover. After cleaning the rest of the intake parts I reinstalled everything and plumbed the wastegate and boost controller as bleeding valve setup.





I haven't had a chance to tune the wastegate duty cycle map yet. But I should have time this weekend if it doesn't rain.

[cleanasse30]

So I tried to tune the boost control today. And when I say tried I mean that as I should have known from the begining my wastegate is too small... Even after setting up the boost controller as a bleed valve I am hitting the boost cut I set at 16psi even with the wastegate at 100% Duty cycle.

I initially had the wastegate setup like this:


I was hoping the wastegate would still flow the same amount of air as it was on spring pressure only, but I'm guessing the boost controller being 100% open causes the pressure going to the diaphragm to drop enough that it causes the wastegate to shut? I think using a T from the boost reference on the turbo causes this. I believe having independent boost lines feeding the top and bottom of the diaphragm so there was no pressure drop on the bottom port would fix the issue so I might do this in the short term, since I'm planning driving down to LA next weekend with the e30. This will just be a band aid solution though, the car needs a bigger wastegate in the long run. Might switch over to running a Tial MV-R this winter.

Any thoughts?

[cleanasse30]

Road trip complete! The car fucking RIPS through canyon roads!!! I'm very pleased with how the suspension feels, power felt great and predictable and it was an amazing week of driving and exploring new parts of the country. It's time to get to sleep, but I'll update with some pictures from along the way in a day or two.