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sleepyhead
sleepyhead Dork
4/16/18 10:28 p.m.

alright, so I got a more detailed image from klodkrawler via email (which is downsized again, but placed for easy comparison sake):

which I tarted up a little bit...

I'll start with the yellow arrow first.  It's tempting to see this being aligned correctly as an indication of proper flow, but I really expect this is more coincidence than anything... I wouldn't read much into it.

The orange arrows are "mud impact" splotches... so their size, direction, and propagation are basically meaningless.

There's about 3 streaks inside the red oval that are encouraging.  They clearly show attached flow that's attached to the duct for the first ~50% of it's length.  There's pooling at the end of them... so it might be because y'all came back in quickly after the off, and it didn't have time to propagate the whole way.  It could be that they ran into debris and stopped propagating because of that.  Or, it could be because the duct is 'kicking up too much' that the flow is slowing down and separating after 50% length.

It's tempting to make a claim about the presence of these streaks only in the "inboard" duct, and not the wider/more-aggressively-expanding outboard duct... but I think there's too much variability going on here to be on any kind of ground about that.

tufts, and two gopros are needed... and they need to be sync'd (start them together, "clap", then mount)... point one at the tufted ducts (tufts being ~2" in length, the lighter the better... not black... probably red... so you can track them across the green of the duct and the black of the splitter); point the second one so it can record the speedometer.  It'd be better if it was pointed at a pitot probe speed output... because wind... but "ground speed" is a start.  If you can run one way down a straight road ~60mph, then flip a u-turn and run back the other way, that'd help negate the wind not being in the speed.

klodkrawler05
klodkrawler05 Reader
4/17/18 9:45 a.m.

alright, so I guess I'm going to have to start doing some tuft testing! for science!

sleepyhead
sleepyhead Dork
4/17/18 12:04 p.m.

you don't have to... only if you want an idea if they're working the way you think they should be wink

alpinecoupe
alpinecoupe New Reader
4/18/18 8:25 a.m.

Would you be willing to share the file for that duct?

I was thinking of doing something similar for an E30 project I am working on, thanks!

klodkrawler05
klodkrawler05 Reader
4/18/18 10:14 a.m.
alpinecoupe said:

Would you be willing to share the file for that duct?

I was thinking of doing something similar for an E30 project I am working on, thanks!

Not just at this point yet, still in the early testing phases!

2GRX7
2GRX7 Reader
4/18/18 11:30 a.m.
klodkrawler05 said:

alright, so I guess I'm going to have to start doing some tuft testing! for science!

How bout some homemade Flo-Viz?....

http://www.apexspeed.com/forums/showthread.php?39641-Flow-Viz

 

klodkrawler05
klodkrawler05 Reader
4/18/18 2:41 p.m.

flow viz you say? more topics to explore! seems we should've printed these things in white to make it easier to get good contrast

 

mazdeuce - Seth
mazdeuce - Seth Mod Squad
4/18/18 2:55 p.m.

Stafford1500 taught us a recipe for it in another thread. Something like tempra paint and some sort of oil? We need to summon him somehow.

2GRX7
2GRX7 Reader
4/18/18 3:57 p.m.
klodkrawler05 said:

flow viz you say? more topics to explore! seems we should've printed these things in white to make it easier to get good contrast

 

How about....

https://www.amazon.com/dp/B00FLXU6HS?aaxitk=3VaOmUyix8tyTbkzn99chg&pd_rd_i=B00FLXU6HS&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=3534726502&pd_rd_wg=oGDXM&pf_rd_r=BQJBPY5P3EM9THWC1YHV&pf_rd_s=desktop-sx-top-slot&pf_rd_t=301&pd_rd_w=MsF9J&pf_rd_i=fluorescent+dye&pd_rd_r=b9426bbc-416e-4bdc-8cb5-c1ebfd2a865c&hsa_cr_id=4926228180801

 

klodkrawler05
klodkrawler05 Reader
6/21/18 11:00 a.m.

Bump! I was hoping to have all sorts of tuft testing or proof that the new aero stuff is awesome. Instead, it's mostly been scramble in free time to make adjustments and sort issues as they arise. 

Since my last post we've run 2 gridlife events and 2 local autocross events. Overall the car has been good, after the first gridlife we decided to lower the car a bit to try to get more front bite.

This is the amount we lowered the car (about .75"):

This ultimately acheived our goal but we way overshot, the front edge of the splitter would dig in under heavy braking zones and cause a shudder throughout the car, which would trigger ABS, the solution was to raise the car back up .25" and then raise the front mount of the splitter by .25"

I'm working on some splitter skids as well for rougher tracks as the splitter still sits about .5" lower than previously thanks to the increased rake. 

The other thing was this made the car incredibly loose in the back, we wound up having to not only dial out some compression in the rear but also wound up removing the rear sway bar. 

During one of our sessions after lowering the car Matt wound up oversteering and sliding off the track backwards into some grass. He was able to drive back onto the track and pulled into the pit to be checked over. When he stopped moving the lack of airflow under the car caused some of the still stuck grass to ignite on the hot exhaust which quickly caught some of the oily bits below on fire. Thankfully the fire crew was nearby and the only real damage was a melted wideband o2 and some reverse light wiring.

That prompted the install of this, which was probably something that should've been in the car long ago:

We've been dealing with some heat soak issues also, previously we'd do 2 laps, cool down, 1 more hot lap then the session would be over. For this year we're really targeting doing 3 hot laps back to back to back in preparation for the 2019 One Lap of America where you have to do that twice a day for a week. Water temps have never been an issue since installing the CSF radiator, however the C&R oil cooler didn't seem to be able to keep up with the heat. So, enter this massive piece from Setrab, oil capacity is now up by a full 2 quarts, and it's rated for 50% more hp than I'm making!

We learned as it turns, out, all that extra blockage in front of the radiator means that now the radiator isn't getting the airflow it was before which caused coolant temps to go up.  After 2 laps water and oil temps were high enough to worry us into back down, sometimes even midway through the 2nd lap. Great, money spent and we made the car worse.

Since we were at Gridlife when we learned this interesting bit of information there wasn't a ton of options or time between sessions, Thankfully Gingerman is only an hour from my house so my brother in law brought out some power tools and a beat up spare bumper from a car we parted out:

This seemed to help a bit, oil temps were still just as bad as they were previously with the C&R cooler BUT, we could now do a 3rd lap at speed without getting into the "DANGER WILL ROBINSON" area.


A bit of temp data from the AIM, all sessions shown were within 5-10 degrees ambient, so not a massive swing. 

2 laps in green are from last fall with the C&R oil cooler in factory location and CSF radiator
2 laps in blue are from this summer with the new cooler in place
2 laps in red are after we cut up the bumper

So, we've got temps back down to where they used to be with the old setup, ie. no improvement. Not captured in this data is that oil temps would continue climbing steadily for the green laps if we started a 3rd one, meanwhile the red laps sort of plateau and hold. so we did get a bit of improvement in length of time we can push the car.


And that brings us up to today. If some is good, more should hopefully be better?
Adding much more comprehensive ducting to the cooler stack:

 

We're also trimming up some angle to help try to get the hood vent extracting more air (and have added a massive 2600cfm radiator fan instead of the 1500cfm one on the car previously)

Hopefully we see some improvement here and none too soon as our next track event is only a week away at Autobahn and the Optima Autocross in Grissom is this coming weekend.

The last idea I have still in mind for cooling is a larger intercooler, get rid of the end tanks blocking so much of the lower grille and instead have it be entirely core, with the end tanks tucked behind the bumper, this should increase airflow which seems to be the best things we've done so far to heat reduction. 

You can see how much space they waste, but with how far outward the charge pipes  are I think it's possible to fab something while keeping the same piping. Unfortunately I'm not a welder so I'll have to farm this work out.

The core which comes with this kit is 20x8x3, I don't see any brand markings on it but I have my suspicions something like the 24x8x3.5 core from Garret might actually let more air through to the heat exchangers as well as cool my IAT's down more (not something that's been an issue but it can't hurt)

I'll make sure my update is not 2 months away this time and hopefully I have some positive cooling results to share!

docwyte
docwyte SuperDork
6/21/18 2:57 p.m.

I would've gone with a side mounted oil cooler, last thing you need is yet another heat exchanger in front of your radiator

klodkrawler05
klodkrawler05 Reader
6/21/18 2:59 p.m.
docwyte said:

I would've gone with a side mounted oil cooler, last thing you need is yet another heat exchanger in front of your radiator

Yes, I'm thinking the 135i/335i guys are already ahead of us on that, we may wind up duplicating their setup. Since we're not using brake ducting anyways the passenger side foglight opening would be a perfect fresh air inlet.

Slippery
Slippery SuperDork
6/21/18 3:26 p.m.
klodkrawler05 said:
docwyte said:

I would've gone with a side mounted oil cooler, last thing you need is yet another heat exchanger in front of your radiator

Yes, I'm thinking the 135i/335i guys are already ahead of us on that, we may wind up duplicating their setup. Since we're not using brake ducting anyways the passenger side foglight opening would be a perfect fresh air inlet.

If you need more space, the driver’s side is the way to go. There is nothing behind the foglight and its closer to the oil filter. 

I know the space behind passenger foglight is blocked. Probably the windshield washer bottle resides there. 

mazdeuce - Seth
mazdeuce - Seth Mod Squad
6/21/18 3:49 p.m.

So the fan is in front of the radiator?

Slippery
Slippery SuperDork
6/21/18 4:48 p.m.
mazdeuce - Seth said:

So the fan is in front of the radiator?

There is one in front for the AC and a mechanical fan clutch behind. Not sure the mechanical has been replaced on this car or not with an electric one. 

klodkrawler05
klodkrawler05 Reader
6/22/18 7:13 a.m.
mazdeuce - Seth said:

So the fan is in front of the radiator?

Behind the radiator. Factory A/C pusher fan in front of radiator has been deleted, mechanical puller fan from the factory has been removed and replaced with one of the biggest electric fans SPAL makes.

In reply to Slippery :

Driver side is better for routing absolutely, unfortunately that's where the intake for the supercharger lives. However, I might be able to do something about re-locating that. hmm.

stylngle2003
stylngle2003 Reader
6/22/18 8:49 a.m.

is that a carbon fiber bumper beam?  if so, that goes down as a TIL (today i learned)

collinskl1
collinskl1 Reader
6/22/18 8:52 a.m.

What material are you using for your ducting?

klodkrawler05
klodkrawler05 Reader
6/22/18 9:31 a.m.

The plastic is available in 10 foot rolls for $20 from speedway: https://www.speedwaymotors.com/Colored-Plastic-Rolls-10-Ft,1557.html

The trick I learned watching others use this is cut off approximately the size you need, then clamp it to something flat in the sun for an hour or 2 to flatten it out before you start making whatever it is. Alternatively I suppose you could use heat to bend it more if needed.

 

Yep! kevlar crash beams were factory on the M3's front/rear compared to the aluminum ones on all other 3 series.

docwyte
docwyte SuperDork
6/22/18 12:05 p.m.

That front pusher fan moves a tremendous amount of air.  The stock clutch fan moves much more air than the Spal.  So with removing both of them and only having the puller Spal, that's a problem for you.

I have the big Spal puller on my E36 but still have the front pusher fan.  It's the only way things stay under control...

Slippery
Slippery SuperDork
6/22/18 12:34 p.m.

In reply to docwyte :

If he has the same Spal puller fan I have on my e36 M3 then you’d be surprised. It sounds like a 747 on take off. 

mazdeuce - Seth
mazdeuce - Seth Mod Squad
6/22/18 12:38 p.m.

What does the shrouding for the SPAL look like? 

I want to ask if you've done any testing with no fan, but then my brain thinks the big problem would be heat soak when you come back off track and with no fan you have no real way of moving the heat. I know on a lot of cars the fan will never come on over about 30mph becasue the act of moving is pushing more air than the fan ever could. So that has me thinking that if you're heat soaking while doing hot laps there is no amount of fan that will solve your issue as you really can't mechanicaly push more air than the car will by driving 100mph. So that has me thinking that you're down to ducting (so that you're not wasting any of that precious 100mph air), moving things out of the way so that the air actually goes where the ducting pushes it (intercooler or ironically, the fan itself) , or increasing cooling capacity again. Someone smarter than me will have to chime in, but my feeling is that if the fan can strip off enough heat to cool the car in grid it's probably already big enough. 

Edit: I guess my question is, can you log when the fan actually runs. Have you? Does it coming on at speed fix anything? 

klodkrawler05
klodkrawler05 Reader
6/22/18 1:05 p.m.

I actually hadn't considered that the factory fans would flow more, I'm trying to remember if I had the hood vents before I switched to the electric fan or not. The Spal fan I got pulls enough air that you can feel it evacuating the hood from near the trunk of the car, which is quite a lot better than the Mishimoto one I took off (which was rated to flow 800cfm less)

I removed the AC condenser in an effort to get more airflow to the important radiator, and in doing so lost the mounting points for the pusher fan.

the other interesting notes we've acquired thus far. If we pretend the car has a 7000 rpm redline instead of an 8200 rpm redline, it never overheats, we can run full sessions in any weather just fine. If driving at our personal 10/10's the car will get oil temps up to 280 within 2 laps but as soon as you enter cool down lap it brings temps right back to normal operating within 2 corners.

One of my electrical engineer friends suggested that the oil temp could be modeled based off the car's perceived usage etc. rather than an actual temp reading. We've ordered stand alone gauges for oil/water to verify that the temps we're seeing are real. We can't trust the AIM any more than the gauge cluster since both pull their data from the CAN system.

Seth, ducting is the spal gasket which seals the entire perimeter of the fan tight to the radiator with the mounting clips through the core shown below.

the fan is on a manual switch, our typical practice has been flip it on in pit out, then pull into our paddock space, shut the car off, let the fan run a bit longer then shut it off also. The car can idle seemingly forever without issue, we've left it idling in pit lane 20 minutes at a time and the gauges never even reach full operating temp.

Your theory about the fan not doing as much at 100mph as the fan could are precisely why I've removed everything I can in front of the heat exchangers and have worked on improving the ducting, hopefully the gurney flap in front of the hood vent helps generate some suction to pull even more air through the radiator faster.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
6/22/18 1:11 p.m.

Could the water pump be cavitating or......something? What if air flow doesn't fix it because air flow isn't the problem?

klodkrawler05
klodkrawler05 Reader
6/22/18 1:45 p.m.
mazdeuce - Seth said:

Could the water pump be cavitating or......something? What if air flow doesn't fix it because air flow isn't the problem?

Hmmm, interesting idea there. The crank pulley is larger than factory, I believe ESS includes all new pulleys, but perhaps the ratios are not corrected and thus lead to overspinning the waterpump. I know some of the race only underdrive pulleys for these cars massively underspin the water pump because at the high rpm's cavitation can be a thing. I should investigate that.

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