SNAFU; high performance 318is build that lives up to the name, Turbo M42 ➞ Turbo M20

[varg]

A/C is must down here. I just did a 134 retrofit on my 84, new condenser, expansion valve, O-rings and rebuild compressor. Blows nice and cold.
Congrats on the garage.!

Gotta have it. The lack of condenser fan is going to hamper its performance at idle though. I'm considering buying an expensive 16" curved blade Spal to replace the clutched fan. Should move a good bit more air at idle than the stock clutch fan and help the condenser out. Shame my powerful Volvo 960 fan won't fit with the M20.

I ile your progress.. Have you considered R152 refrigerant? My friend swears by it as a cheap alternative. He has a tool to extract it from those air duster cans.

I've considered propane based on other people's experiences but never though of that. Propane makes a good refrigerant (see this and this) and is cheap and easy to get. You can't get those canned air dusters without a bittering agent in them, I'd be concerned about the reactivity of that compound in the system. If this system can't handle the heat with R134a I very well might vac it down and put propane in its place.

Nice work! Having a garage is a godsend.

Thanks, sure is! :up:

[zwill23]

I was feeling quite sold on ITB's so I could also run AC here in Texas...

Stop swaying my build goals damn it...

[varg]

I was feeling quite sold on ITB's so I could also run AC here in Texas...

Stop swaying my build goals damn it...

Well, now you know it can be done. There's a lot to consider when making those decisions but I never considered ITBs for a second because I want cheap power :devil:

[varg]

It has been a busy summer for my E30, I've been putting a lot of miles on it. As soon as the summer heat started to kick in, my coolant temp started climbing too. It was fine (185-195°) when I'm moving, but once I encountered traffic it would climb past 200°, which I do not like. The fan clutch passed the magazine test, but my fan looked wrong (9 slightly undersized blades instead of 11 broad ones) so I replaced it with a new 11 blade unit, it made only a small difference. While I waited for the new fan I drove around hoodless to beat the heat, but I quickly tired of that.







Then I flushed the radiator and got a bunch of crap out of it, that made barely any difference. So I finally dropped some cash and ordered a new Z3M radiator, which is a direct fit upgrade for an E30 and is a little thicker than the stock radiator. Between the thicker core and it being brand new and not coated in filth inside and out, I think this should do the trick.

New


Old


It drops right in, but the fan shroud doesn't fit between the fan and the radiator now.


Will it solve the problem? I sure hope so. I'm going to have to get creative and figure out a shroud.

While I'm at it, time for an AC update. It works well while driving, not so much in traffic, and it has trouble cooling the car down when it has been sitting in the sun for a while. My car is like an oven in the summer heat with this worn out black paint. There's no room for a condenser fan with the big intercooler, so there isn't much I can do to improve the AC performance at idle. I'm exploring other options.

[econti]

Z3M still has integrated expansion tank yeah? Think I can see it on the side?

Good find though, I'll have to get one for mine. Aus heat with turbo engine and i/c in front of rad will be nasty, so that should do the trick

[varg]

No it's pretty much the same as a 325i radiator, it just has a thicker core, the small hose at the top left of the pictures goes to the 325i expansion tank.

As for its performance, my idle is definitely significantly cooler, and it is a couple of degrees cooler than it was before while on the road. But unfortunately with the AC on the temperature still rises, just more slowly than before and not to the same degree.

[megu2ice]

Did you ever rebuild your compressor? My AC system is similar to yours and doesn't cool enough to deal with the afternoon temps. Rebuilding the compressor is my next option.

[varg]

No, the pressures are ok so it doesn't need it. That's the diagnostic test for a bad compressor, have you checked your pressures?

[megu2ice]

No I can't get a reading on the high pressure side, I'm assuming the valve needs to be replaced but I don't want to have to refill the system. I'm going to start adding some insulation to the low-pressure line that runs next to the turbo. I'll let you know if it makes a difference. What temps are you seeing at the vents?

[varg]

Haven't been doing much of any interest with my E30 lately, most of my time with it is spent commuting. Fun car stuff is too expensive (have to take a day off of work + pay entry to do an autocross, track days are completely out of the question), so I've been getting better mileage out of my money with other hobbies. I can get a lot more fun than one autocross by spending one autocross worth of money on RC airplane stuff.




Hurricane Irma wasn't too rough on us here, we got lucky, and the E30 sat safely in the garage the whole time with all of the patio furniture and stuff.



I've been fighting these coolant temp issues all summer. I replaced the fan clutch this week, so everything in the cooling system is now new, and the problem persists. Temps are still fine at freeway speeds, though a little higher than I would expect with a 160° thermostat (typically 185-190° on a hot day), but the coolant temp needle parks at the second mark when I'm cruising even with the AC on and that's a good place for it. I'm convinced the issue is due to the intercooler restricting fresh air flow, enough is forced through to keep cool while driving, but the fan doesn't create that kind of pressure differential, and it doesn't have a shroud to help it either. I cut a couple of pieces of corrugated plastic and some foam to act as ducting between radiator condenser/radiator stack ducting but it didn't help. I haven't been able to find any powerful electric fans that I'm sure will fit in place of the mechanical fan, and I'm not about to drop another $200 on a nice fan only to have it do no better than the unshrouded mechanical fan is.

At this point I'm pretty sure I'm going to install a smaller intercooler so I can run an aux fan and have less flow restriction. I'd like to find something with a 24" wide, 3" deep core like my current IC, but 6-8" tall instead of 12", closest I've found is 24x6x2.5 core. An IC that small might not be sufficient for my power goals without some sort of supplementary charge cooling like a water/methanol injection system, but another problem is it flowing well enough to not create significant pressure drop. Even if my 24x12x3 intercooler is only cooling as well as a 24x6x2.5 intercooler would due to having poor air flow over the top half, the larger core still supports more flow.

As usual I'm in uncharted territory here, nobody builds a turbo E30 and keeps the AC. In an ideal world I'd have the tools, time and skills to hack the core support and sheet metal behind the valance to bits and replace it with a welded up tube frame and some good ducting, but I don't have the tools, time or skills to do it.

No I can't get a reading on the high pressure side, I'm assuming the valve needs to be replaced but I don't want to have to refill the system. I'm going to start adding some insulation to the low-pressure line that runs next to the turbo. I'll let you know if it makes a difference. What temps are you seeing at the vents?

Mid 50s when driving on the highway, they climb at idle to mid 60s/low 70s. For reference that is with outside temperatures in the low 90s and humidity levels typically over 70%.

[downforce22]

From reading Maximum Boost (Corky Bell) and Forced Induction Performance Tuning ( A. Graham Bell), the core thickness produces less and less performance gains as it increases. Frontal surface area is the most important and there are some diagrams that include ducting and shrouding for the front of the intercooler for maximum air flow through it. Another consideration is airflow out of the radiator, around the engine and out of the engine bay. I wouldn't worry about the core thickness much. I would look for a 24" x 8"x 2.5" if you think the intercooler is causing problems.

Are you sure your thermostat isn't a 180 F thermostat? That is is the normal temp thermostat and unless you test it in boiling water, I wouldn't be sure it is a 160 F t-stat. My car usually runs 180-190 and it is perfectly healthy, I only worry if it gets up to 200 F. If the AC isn't cool enough, I believe you can add more refrigerant to lower the temperature.

Also, the Span fan is a good option for about $150 with mounts and bracket. You want the puller fan. There were an old and new version and sometime you can find it cheaper with the old part number.

Old number VA18-AP71/LL-59A

Here is one for $99 shipped: http://www.ebay.com/itm/SPAL-16-Curv...ZZrfut&vxp=mtr

New number 30102049

[ForcedFirebird]

(typically 185-190° on a hot day)

Totally normal. The m20 makes it's most power at 190, even, I have dyno tested this on spec e30's...

[varg]

From reading Maximum Boost (Corky Bell) and Forced Induction Performance Tuning ( A. Graham Bell), the core thickness produces less and less performance gains as it increases. Frontal surface area is the most important and there are some diagrams that include ducting and shrouding for the front of the intercooler for maximum air flow through it. Another consideration is airflow out of the radiator, around the engine and out of the engine bay. I wouldn't worry about the core thickness much. I would look for a 24" x 8"2.5 if you think the intercooler is causing problems.

Are you sure your thermostat isn't a 180 F thermostat? That is is the normal temp thermostat and unless you test it in boiling water, I wouldn't be sure it is a 160 F t-stat. My car usually runs 180-190 and it is perfectly healthy, I only worry if it gets up to 200 F. If the AC isn't cool enough, I believe you can add more refrigerant to lower the temperature.

Also, the Span fan is a good option for about $150 with mounts and bracket. You wants the puller fan. There were an old and new version and sometime you can find it cheaper with the old part number.

Old number VA18-AP71/LL-59A

Here is one for $99 shipped: http://www.ebay.com/itm/SPAL-16-Curv...ZZrfut&vxp=mtr

New number 30102049

I doubt we're in an area of diminishing returns with regards to core thickness in an intercooler as small as the one I'm talking about, and of the quality I can afford. I'm more concerned with the smaller core creating significant pressure drop when I turn the boost up though. I've been searching for intercoolers that fit the bill and have only found the one 24x6x2.5 that seems like it would work for me. If I could weld aluminum I'd just cut the core and end tanks down on my big cheapo that I have now, but I'm not going to spend a quality intercooler's worth of money getting a cheapo core cut and welded.

As for the thermostat, I specifically chose the 160° to replace my 180° thermostat. The plan was to run closer to 160° on the highway, giving me more headroom when I stop at a long light and the temperature starts climbing because the condenser is heating the already restricted airflow that is going through the radiator. Obviously a cooler thermostat won't fix a problem like this, but I was hoping for at least 10° more headroom for those times when I'm stopped and the temperature starts to climb. I do not like to see anything close to 200°, but if I'm stopped with the AC on it will get there in a couple of minutes and keep rising until I have to shut the AC off, open the windows and blast the heater to bring it back down. It's a hateful thing to have to do but M20 heads seem to crack at the slightest hint of overheating so ideally I do not want to see temperatures higher than 200°, ever. Thanks for the tip on the fan, but I'm probably not going for it, I can't see it fixing my problem and I've already thrown a new radiator, fan, fan clutch and thermostat at this problem. I think it's time to stop trying to cool well in spite of the restriction and fix the restriction.

As for the AC, the charge was done by weight and pressure, adding more wouldn't do me any good, the condenser heat soaks at a stop. Since there's no aux fan to prevent it, it can't be helped until I can fit one.

Totally normal. The m20 makes it's most power at 190, even, I have dyno tested this on spec e30's...

I wouldn't even be mentioning it if the car sat at 190° all of the time, I don't think that's too hot, but I don't like seeing 200°, let alone more. My warmup enrichment is off at 160°, so if I could run it closer to that I would.

[ForcedFirebird]

160 isn't warm enough, though. For reference, my van with an ls variant runs constant at 205, the ls1 Mercedes was always 210 at the track, didn't stop it from completing 14hr races, the e30's run at 200-210 for hours on end too. We consider 215 and up to be "overheating".

Where is the stock gauge reading (if yours is still fairly accurate)?

[varg]

I cut the bottom right corner and center section off of my fan shroud, it wouldn't fit between the fan and the radiator core intact, so now it's 3/4 of a shroud. Better than nothing, right? I also sat in front of my car with it running, burning stuff so I could see the airflow going through the grille. Not impressed considering the fact that my old Turbo Volvo would hold a sheet of paper against the grille with the electric fan on, and you could feel the air moving towards the grille with your hand on my old pickup trucks.



And I made an unfortunate discovery, it's not just my sunroof panel that is rusting, the roof is too. This repair just got 10x more painful.

Fuck sunroofs. If I have to drop the headliner to fix the roof rust, the whole damn sunroof assembly is coming out for good.

160 isn't warm enough, though. For reference, my van with an ls variant runs constant at 205, the ls1 Mercedes was always 210 at the track, didn't stop it from completing 14hr races, the e30's run at 200-210 for hours on end too. We consider 215 and up to be "overheating".

Where is the stock gauge reading (if yours is still fairly accurate)?

We discussed this over text, but for the purposes of the thread:
-200° happens approximately at the halfway mark of the gauge
-I've never seen the gauge go past 3/4 mark, even when the M42 overheated after the cylinder head crack, which was around 220°
-I just prefer the engine to run cooler than it does, as long as it's consistently above my WUE cutoff point of 160° and never above 200° I'd call it good
-I'm not as worried about the head after hearing that you've seen M20s survive higher temps than 220°, but I'm still trying to keep temperatures below 200° out of an abundance of caution.