[kenneth]

Looks like the ARs are not doing too good on track. Is it the AR additional cooler in front of the radiator?

Edit: nevermind, just saw it is mounted in front of radiator

[TurboBimmer]

Originally Posted by kenneth

Looks like the ARs are not doing too good on track. Is it the AR additional cooler in front of the radiator?

Edit: nevermind, just saw it is mounted in front of radiator

+1 I would have expected the ARs to perform better. To me it looks like our stock OC is undersized to a point where even adding a 2nd OC won't be enough to keep temps in range on the track.

[mid-corner fun]

Originally Posted by UltraRacer13

Maybe the STETT's weakness is that it is open to debris in the wheel well. I need to check mine now, to see what it picked up at the track.

No debris whatsoever after one track event:



A pic of the removed air duct, air flows directly to the oil cooler and to the brakes behind it.

[kenneth]

Originally Posted by Autobahn335i

+1 I would have expected the ARs to perform better. To me it looks like our stock OC is undersized to a point where even adding a 2nd OC won't be enough to keep temps in range on the track.

Thinking about it, The 2nd oil cooler is parallel to the stock oil cooler (not in line) so it competes for incoming oil and for oil return with the stock oil cooler. The oil split is after the thermostat. Which cooler processes more oil than the other is anybody's guess.

Oil temperature is brought down for sure, but efficiency may less than having a single bigger oil cooler just because of the design of the oil feed and return?

[TurboBimmer]

Originally Posted by kenneth

Thinking about it, The 2nd oil cooler is parallel to the stock oil cooler (not in line) so it competes for incoming oil and for oil return with the stock oil cooler. The oil split is after the thermostat. Which cooler processes more oil than the other is anybody's guess.

Oil temperature is brought down for sure, but efficiency may less than having a single bigger oil cooler just because of the design of the oil feed and return?

Well, when I bought the AR oil cooler I expected that the manufacturer had actually led the necessary R&D to provide a working solution

Now I'm not suggesting that it doesn't provide any improvement at all, but the findings in this thread show that it's clearly not enough to push our cars around a racetrack safely.

[UltraRacer13]

I would just like to say how much I enjoy this thread. If only all the threads on this site were like this one. Everyone is providing informative posts, no bashing, no "mine is better", just an attitude of, hey lets compare these options the best we can and find what is and what is not working and why. Great thread guys!

[kenneth]

Originally Posted by kenneth

Thinking about it, The 2nd oil cooler is parallel to the stock oil cooler (not in line) so it competes for incoming oil and for oil return with the stock oil cooler. The oil split is after the thermostat. Which cooler processes more oil than the other is anybody's guess.

Oil temperature is brought down for sure, but efficiency may less than having a single bigger oil cooler just because of the design of the oil feed and return?

Originally Posted by Autobahn335i

Well, when I bought the AR oil cooler I expected that the manufacturer had actually led the necessary R&D to provide a working solution

Now I'm not suggesting that it doesn't provide any improvement at all, but the findings in this thread show that it's clearly not enough to push our cars around a racetrack safely.

I have the AR too, and I think I was in the very first group to have this.
While I did see a slight improvement, I couldn't tell hos much more efficient they were. The tracks I go to have some long fast straights. Glad to see that some have logged the temperature.

[mid-corner fun]

Added another row to our chart.

Good news: Another limp-free event with oil staying below 250F!!!

Bad news: Ambient was low and it was raining so this data is no indication of what will happen in hot weather.

Interesting news: I logged water temps for the first time at the track and the result was well, interesting: I'd hit ~98C at the turns, drop to 90-92C on the straights and then water would skyrocket to 109C the moment I pit-in (driving through the paddock). This was consistent across all sessions over 2 days.

[The HACK]

Originally Posted by PeterM1

Interesting news: I logged water temps for the first time at the track and the result was well, interesting: I'd hit ~98C at the turns, drop to 90-92C on the straights and then water would skyrocket to 109C the moment I pit-in (driving through the paddock). This was consistent across all sessions over 2 days.

Would it surprised anyone if I have a theory on this?

The turbo(s) on these cars are cooled by both oil and water. There's a heat exchanger between the oil used to cool the turbo while in operation, and water used to cool the engine.

So while the car is moving at high speed, there's more airflow going through the radiator, therefore cooling is more efficient even if you're at higher boost and full throttle. And the second you pit in the radiator no longer has the same airflow you would get by having the car move at high speed, and therefore the cooling efficiency drops immediately while the heat in the turbo is just starting to be evacuated.

I have another theory on why these cars seems to suffer so badly in a school environment. Let's say there's 4-5 sessions throughout the day. That means you're on track for 1/2 hour, off for about an hour to hour and a half, and then back on for another 1/2. While sitting in the pit with the car off, like most modern turbo designs the car/engine uses the coolant to cool off the red-hot turbo, so the heat continues to build up in the coolant and in an hour there's still plenty of residual heat in the coolant, and since there's no cool air flowing through the radiator there's no way to effectively evacuate the heat.

If anyone of you wants to try this, next time you go to the track, instead of shutting off the car immediately after you come in to the pit, drive around for 5 minutes with minimum boost (like cruising around the block at 2,000 RPM or something) to force both the radiator and the oil cooler to take a few more minutes to try and cool off the turbo. See if that will extend the thermal capacity of the system. And once you're parked, spray/mist some water on the radiator to help it evacuate heat (by vaporizing the water). I'm guessing that if my theory about the coolant acting as the cooling agent for the turbo once the car is shut off is why the coolant seems to trigger limp so often, this will go a very long way to stave off the problem in addition to upgraded oil and water cooling.

In fact, you guys may want to consider logging which session(s) limp mode comes on. If I'm correct, water temp triggered limp mode will likely come on during the later sessions, and especially if the schedule forces like a back to back session or only 1 session in between breaks.

[mid-corner fun]

What really surprised me was the volatility of water temps, all it took was a single straight to lower them and a couple of turns to rise them and the cycle continued, meanwhile oil was holding steady at ~250F. I can't wait to see what happens this summer, we need some water data points when oil (stock cooler or otherwise) hits 270-280F.

A few pages back I posted a short video with 2 limp modes from last year, OEM cooler, no Mocool and just an FMIC if I remember well. Now that I can correlate the water temp pattern I can see that both limp modes occurred at the end of a series of turns. With the stock oil cooler and OEM coolant/radiator, I bet we've been riding at the water level threshold all along.

Also, although in this particular case my data says otherwise, I think you're right on the coolant temp not recovering between sessions. In this case, humidity was already at 100% and with the hood open for 70 mins in-between sessions and low ambient temps, water temps fully recovered to ~77C every time. Better data next time.

My next event is a month away, hopefully someone else will hit the track sooner for more data.

Originally Posted by The HACK

So while the car is moving at high speed, there's more airflow going through the radiator, therefore cooling is more efficient even if you're at higher boost and full throttle. And the second you pit in the radiator no longer has the same airflow you would get by having the car move at high speed, and therefore the cooling efficiency drops immediately while the heat in the turbo is just starting to be evacuated.

I have another theory on why these cars seems to suffer so badly in a school environment. Let's say there's 4-5 sessions throughout the day. That means you're on track for 1/2 hour, off for about an hour to hour and a half, and then back on for another 1/2. While sitting in the pit with the car off, like most modern turbo designs the car/engine uses the coolant to cool off the red-hot turbo, so the heat continues to build up in the coolant and in an hour there's still plenty of residual heat in the coolant, and since there's no cool air flowing through the radiator there's no way to effectively evacuate the heat.

[BRO]

A bigger fan on the radiator would be effective at getting the heat out during low speed turns after straights. BMW Performance Power Kit has one.

[Turkeybaster115]

Originally Posted by PeterM1

My next event is a month away, hopefully someone else will hit the track sooner for more data.

I'll be at the track on sunday. Its going to be 85 degrees with 70% humidity. A real test for my set up: Stock Auto, AR design oil cooler, no OEM oil cooler, 30/70 Total coolant + Gunk Liquid cool coolant additive. I'll report back my data.

[UltraRacer13]

I would like to see if Cobb can do what Dinan does and make the water pump inrease it's performance. Anyone know more about what the Dinan does?

[Turkeybaster115]

Originally Posted by The HACK

Would it surprised anyone if I have a theory on this?
The turbo(s) on these cars are cooled by both oil and water. There's a heat exchanger between the oil used to cool the turbo while in operation, and water used to cool the engine.
So while the car is moving at high speed, there's more airflow going through the radiator, therefore cooling is more efficient even if you're at higher boost and full throttle. And the second you pit in the radiator no longer has the same airflow you would get by having the car move at high speed, and therefore the cooling efficiency drops immediately while the heat in the turbo is just starting to be evacuated.

Damn good theory, but might I add that at WOT in the straights, the electronic water pump is incrementally increasing its load, and decrasing it, upon decceleration, and low speed maneuvering

Originally Posted by The HACK

I'm guessing that if my theory about the coolant acting as the cooling agent for the turbo once the car is shut off is why the coolant seems to trigger limp so often, this will go a very long way to stave off the problem in addition to upgraded oil and water cooling.

As Mr. 5 has eluded to in the past, doesn't the pre-programmed electronic water pump negate any type of surface area increase? In other words it seems that the coolant mix in these cars influences water temps MUCH more than increasing the radiator's size. i.e: 100% distilled water + coolant additive stock radiator > 50/50 coolant water mix + larger radiator

[BRO]

Originally Posted by Turkeybaster115

Damn good theory, but might I add that at WOT in the straights, the electronic water pump is incrementally increasing its load, and decrasing it, upon decceleration, and low speed maneuvering

Are you sure about this? I would expect the water pump output to be proportional to temperature, not speed. And at track temperatures it would be running full out on straights and corners.

[The HACK]

Originally Posted by BRO

Are you sure about this? I would expect the water pump output to be proportional to temperature, not speed. And at track temperatures it would be running full out on straights and corners.

As my advancing age is robbing my once near phtographic memory (getting old sucks. Middle age sucks. Binge drinking in college was fun but sucks once you hit 40), I can't be sure if this is accurate. But I recall reading a Steve Dinan white paper on this particular engine that states the water pump varies speed both based on temperature AND engine RPM AND load. The wonderful benefit of a fully electronically driven pump.

Can't verify the actual info so take it for what it's worth. Like I said, memory ain't what it used to be (10 years ago I'd be able to dig it up within 5 minutes).

[SloppyJoe]

just came back from streets of willow last weekend.

Car performed like a champ except for the second session where I limped due to my VANOS solenoid.

never saw temperature above 250F
ambient temperature ~ 60F
logged my coolant temp using the secret menu and saw max temperature of 98C.
It slowly creeped up and on my last few laps of the session it was pretty much stuck at 98C

my best time of the day was 1:34:55, so im definitely not pushing my car as hard as vwong.

I have STETT stage 2 with 180F thermostat and OEM coolant.

car is AT.

[mid-corner fun]

Originally Posted by SloppyJoe

just came back from streets of willow last weekend.

Car performed like a champ except for the second session where I limped due to my VANOS solenoid.

never saw temperature above 250F
ambient temperature ~ 60F
logged my coolant temp using the secret menu and saw max temperature of 98C.
It slowly creeped up and on my last few laps of the session it was pretty much stuck at 98C

my best time of the day was 1:34:55, so im definitely not pushing my car as hard as vwong.

I have STETT stage 2 with 180F thermostat and OEM coolant.

car is AT.

Very nice. I like the oil cooler pattern that's developing, we now have 3 reference points of STETT stg2 staying at 250F at the track.

Interesting that your water temps held steady at 98C but that's with the OEM coolant mix, mine were rapidly dropping and increasing with water/mocool.

By the way, is your thermostat making a loud ticking noise when it opens at 180F? Annoying as hell as it resonates through the cabin. Also, the thermostat bracket is so flimsy that the thermostat unit slides out of it every couple of weeks. I'm still dealing with STETT on these issues and I don't like their responses so far. Their first attempt was to blame it on the thermostat vendor, when I took the approach that it's a STETT kit they're selling they're now trying to blame the installer. Not happy with their support so far.

[SloppyJoe]

i forgot to mention i had my heater on full blast (it was chilly that day ), that might have helped a bit.

about the thermostat, i haven't heard any noise from it yet, but I didn't really pay attention, i installed my LSD at the same time as the oil cooler so I thought all the new noises i heard was from the LSD. will pay attention to it now that you mentioned.

The bracket is indeed kind of flimsy. The way it is installed on my car the cable is kind of tight so it holds the thermostat in place.

Btw the oil lines on my kit the lines from thermostat to the cooler is way too long, where as the line from the delete plate to the thermostat is really short. the return line has to be stretched like 3mm to get it to fit... I haven't contacted STETT about this yet.

[mid-corner fun]

Originally Posted by SloppyJoe

Btw the oil lines on my kit the lines from thermostat to the cooler is way too long, where as the line from the delete plate to the thermostat is really short. the return line has to be stretched like 3mm to get it to fit... I haven't contacted STETT about this yet.

Same here. The oil lines from the thermostat to the cooler are so long that they push (slide) the bottom part of thermostat out of the bracket and also rub against the inside part of the wheel liner, based on the marks I see. Since I'm not getting any help from STETT on this, I'm thinking of installing rubber grommets at the top and bottom to see if the vibration goes away, the bracket is so flimsy that you can bend/lift the metal part with your fingers:

[Turkeybaster115]

Originally Posted by PeterM1

Same here. The oil lines from the thermostat to the cooler are so long that they push (slide) the bottom part of thermostat out of the bracket and also rub against the inside part of the wheel liner, based on the marks I see. Since I'm not getting any help from STETT on this, I'm thinking of installing rubber grommets at the top and bottom to see if the vibration goes away, the bracket is so flimsy that you can bend/lift the metal part with your fingers:

For the price you paid, you guys shouldn't be dealing with these types of issues. I'd keep bitching at STETT, until these things are resolved to your satisfaction. You can also write about these problems on STETT vendor threads, so that potential buyers are made aware.

[Kevin@AKMotorwerk]

Originally Posted by PeterM1

Same here. The oil lines from the thermostat to the cooler are so long that they push (slide) the bottom part of thermostat out of the bracket and also rub against the inside part of the wheel liner, based on the marks I see. Since I'm not getting any help from STETT on this, I'm thinking of installing rubber grommets at the top and bottom to see if the vibration goes away, the bracket is so flimsy that you can bend/lift the metal part with your fingers:

that bracket is so flimsy its not even funny, and the nipples on the thermostat have literally 1-2mm of protrusion thru the bracket, so the slightest movement makes it pop out of the holder