VGT Turbo M20 Sleeper ('87 325 Sedan)

[2mAn]

This thing is quite the sleeper!... Have you dyno'd it yet? and what tires are holding this together?

[mikey.antonakakis]

Also replaced the "churning butter feel" old shifter setup with Garagistic chassis mounted shifter. New DSSR and selector joint from Garagistic too. This is the medium length shift lever with delrin knob.

[mikey.antonakakis]

Another sub-project has been some exhaust work. Rerouted wastegate dump from screamer pipe to downpipe. Also swapped mufflers, welded up an entirely new muffler section, including a more e30-esque exhaust tip.

[mikey.antonakakis]

Updates!
Car has been great so far, although it sat all winter. Last year it developed a couple small coolant leaks, with a few drops left on the ground after parking. Combo of thermostat o-ring (easy, fixed last year) and very old cracked radiator (not as easy). My car is a 4/87 build, just at the end of the early models, which means it had an early cooling system. Early radiators are now much more expensive than later radiators, so I decided to swap to the later system. This end up being… rather involved. Radiator inlet/outlet layout is almost exactly opposite locations, water pump is different, and of course the hoses are different too. I was already using a later style coolant reservoir, so that much was already done.

With my water-air intercooler setup, I run the charge pipe across the engine bay directly behind the top of the radiator. With the old cooling setup it just barely cleared the hoses, and it became clear that with the set of new CATuning silicone cooling hoses there was no chance of “stock” hoses fitting (I should point out that the CATuning hoses don’t perfectly match stock rubber hoses, bends generally aren’t as tight, giving even worse clearance for my charge pipe). Combining that issue with my relocated oil filter living exactly where the passenger side radiator hose exits, my oil catch can living exactly where the other radiator hose exits, and some other minor challenges, I ended up with more work than planned to do the early-to-late cooling system conversion.

After a lot of head scratching, I ended up using the stock rubber hose from thermostat to water pump (tighter bends than the silicone hose leaves it closer to the engine), and to snake around my charge pipe and intercooler I ended up making a stainless pipe to go from thermostat to driver side radiator nipple. I also had to remake that charge pipe from turbo to intercooler to make more space for the hoses. While I was doing all this, I ended up rerouting catch can hoses, turbo water feed, and plenty of other stuff (wiring, etc.).

Also relocated the oil filter relocation kit from inboard side of passenger frame rail just behind radiator to the area where the AC receiver drier used to sit. Only ended up needing to modify one hose for that, which was a nice change of pace.

[downforce22]

That would be cool to meet up, I assumed you were in denver, send me a PM and maybe we can chat e30 turbo sometime

[mikey.antonakakis]

Whoops, sorry for disappearing for a while! I think I had email notifications turned off...Thanks for all the kind words!

great thread, thanks for posting your map. I was working on mine and added some timing in the 80 kpa region to match timing in the lower zones. I am also at 6000 feet asl in colorado springs and running a m20b31 stroker turbo with stock 885 head and 9.5:1 CR

I'm also in Springs - I have a good buddy with a white iX (and a couple of other e30s - one to restore, one for parts). Maybe we should meet up sometime?

tschultz,
I am running two 3-port MAC solenoids: https://www.amazon.com/gp/product/B00YBN3DRO/
I haven't gone to closed-loop control yet, but hardly drove the car all winter... now that the weather is getting nice again, I'll be driving more. I need to fix a leaking thermostat gasket before I do much more driving, though. If you're not planning to adjust your boost often, a simpler setup than PID would be to just use the solenoid like a switch. Run it in line with the bottom WG port, close it/vent it (prevent turbo pressure from opening the WG) until you hit 6psi. Of course there's no failsafe there, so make sure if you try that, you have overboost protection enabled! Although probably not too much worry at 6psi. If that's not aggressive enough, you might be able to plumb up a 4-port solenoid to switch between pressurizing the top of the WG below 6psi and then switching to venting the top and pressurizing the bottom above 6psi (for reasons I can't fully remember, two 3-port solenoids seemed to give me the best control, probably since they can be controlled fully independently).

AWD_E30, I finally replied to your PM - didn't see that you were also planning for HE351VE. Might be a tight fit in an iX!

[AWD_E30]

Nice work Mikey! Your posts here have encouraged me to buy a HE351VE for my 325iX. I'll hitting you up via PM for some more details on your setup. I don't want to clog up your build thread. Keep up the good work this is awesome!!

[tschultz]

Great work, a lot of progress here-- this thread almost doesn't do all your efforts justice! Curious to see where this goes.

Are you using the MAC 4 port valve PN: 46A-AA1-JDBA-1BA? I was contemplating installing one for better spool on my M30b34 turbo as I believe my low compression (8.0:1) and wastegate spring opening early (6psi) is hurting my power onset. Although I wasn't sure I wanted to use the PID control, I figured it could give some performance benefit (and I don't want a CO2 system).



I suppose I could buy the 4 port and try it out both ways. I just need to decide if I think I will let the controller/valve pressure the bottom port or leave it at manifold pressure like a 3 port boost controller.

Any thoughts?

[downforce22]

great thread, thanks for posting your map. I was working on mine and added some timing in the 80 kpa region to match timing in the lower zones. I am also at 6000 feet asl in colorado springs and running a m20b31 stroker turbo with stock 885 head and 9.5:1 CR

[mikey.antonakakis]

Oil cooler seems quite effective even with less-than-ideal airflow. Hot idle is now ~20psi vs ~12psi previously, and measured in a different location with significant pressure drop compared to before. Now measured at the output of the cooler before going back into the block, instead of at the filter output, so it has an additional length of -8AN hose and the oil cooler.

The compressor is very loud, being mounted to the rear deck. The solenoid is switching too frequently with the current algorithm/tuning, but even so it doesn't run too often (maybe every 10-20min when I'm doing a lot of throttle modulation). I may swap to a CO2 bottle at some point, but this works for now.

Yesterday was a nice cool day, and I had to make a trip first thing in the morning. Floored it in second gear getting on the interstate and lit up the tires, back end got a little squirrely. I'm using MAT retard, so I think that couple of extra degrees of timing made a pretty significant difference in power. Going to do some more street tuning before going to a dyno, and maybe add water/meth so I can run more aggressive timing, since it seems like most of the time I'm leaving a good amount of power on the table... (premium from the pumps here is only 91 octane).

[mikey.antonakakis]

Been dragging my feet a bit this last week. Oil cooler is installed, and after a quick test drive doesn't seem to be leaking, at least not in any obvious manner... I was a little skeptical of the latest AN hose kit I ordered from Amazon, but so far so good. The first kit I got a few months ago seemed to be of better quality, and has had zero leaks, even after getting things really nice and hot on long highway drives on warm days recently. At some point I'll probably go back and replicate things with some name-brand fittings and hose, now that I know exactly what sizes and shapes I need for each fitting.

While I have the front bumper and valence off, I have been wondering a bit about trying to make some ducting for the radiator, water-air intercooler heat exchanger, and the oil cooler. Right now there's no edge sealing of any sort for the IC heat exchanger or the oil cooler, and they sit proud of the radiator by about an inch, so I don't suspect there's actually a ton of air going through them. Radiator is at least decently sealed on the perimeter, but no ducting on either end, nor an undertray (car hasn't ever had one since it's been in my possession). I had a NB Miata I was daily driving a year ago, through a very hot summer, and I know sealing and ducting and undertray made an enormous impact on that car's cooling - I was always borderline overheating (even with thermostat relocation and upgrades) until I got the airflow managed. My e30 isn't overheating, but it certainly wouldn't hurt to try getting better airflow through my heat exchangers...

It seems like some e30s over the years came with some amount of ducting on the front of the radiator? Something like this?

[mikey.antonakakis]

Maybe you had a boost leak?

That should have resulted in higher speed for a given pressure ratio (had it happen before, when I accidentally fed manifold pressure to the wrong side of the blowoff valve). I'll be keeping an eye on it, as I didn't change anything other than a little bit of microcontroller code. There's a chance something got thrown off with the data side of it. Oh well, at least it's working now.

Oil cooler install started today. Nothing fancy, small cheap unit from Amazon. Just to help a bit in the hot weather. Coolant temps sit around 190F cruising around on warm days, 200F max on long uphill climbs at low speed. Not monitoring oil temp yet, but the 10W-60 I'm using seems to keep pressure better when it gets hot than the 10W-40 or whatever I was using prior.

[varg]

Maybe you had a boost leak?

[mikey.antonakakis]

Tested it out last night, with very simple control method: pressurize the dome until MAP is within 10kPa of boost target, and then vent it to atmosphere. Subjectively it seemed to help the spool, especially at lower rpm.

There was, however, one strange difference: my last test a couple weeks ago with wastegate blowing open, I was running 80k-90k shaft speed at full boost of ~185kPa MAP. Last night was the same ultimate wastegate setting, however I was at higher altitude, so seeing a higher pressure ratio. Despite that, shaft speed DECREASED a bunch, I was running 65k-75k. 15k lower shaft speed despite higher pressure ratio? The overlaid logs are aligned to engine rpm, and I went WOT just slightly later on the lighter lines (from a couple weeks ago).

EDIT: Must have been some sort of data corruption, otherwise something else strange happened. Speeds are back to normal again, just went for a short spin.

[mikey.antonakakis]

Compressor installed in the trunk and working, boost solenoid driver circuits built and installed, boost solenoids installed and wired. Just need to add the programming to the microcontroller, and hopefully end up with better spool.
I also ran a wire for a wastegate dome pressure sensor to add later on, since I have everything else in place to run dome pressure control.

Hopefully I'll have a chance to test it tonight.