Might be worth reaching out to one of the teams running the B58 M240i in pirelli world challenge to see what they say in regard to cooling.Gents,
All the latest >500PS M-cars use a water/air intercooler, with only a ~30mm thick heat exchanger blocking the radiator. It is also interesting to note that the B58-engined cars now come with a water/freon AC condenser to further maximize airspeed into the radiator core, this is very easily integrated into the low-temperature cooling circuit if you're already running a W2A core. I will be studying this carefully and will be posting more about it in my build thread shortly...
This is hard to believe, and conflicts with my data. I know the 7 HD version is better than the nonHD but still... Also I did not see any significant improvement in coolant temps when moving from 7.5 to 7. If this is really happening, it might be because there is more room in front of the FMIC on a Z4.OK, some findings following three terrific days on track at VIR. As I posted earlier, I was seeing my IATs rise 75-80 degrees over ambient during 20-25 minute track sessions with my very large stepped intercooler due to heat soak. With the way smaller (and less costly), non-stepped 7" VRSF HD intercooler, the delta over ambient was 60-63 degrees -- a significant improvement.
Additionally, my coolant temps dropped 5-10 degrees (generally staying between 196 - 205 F), presumably because my CSF radiator got greater airflow.
Please post your ambient temps and conditions (preferably a log that also shows driving) for each data point (7.5 vs 7). Especially coolant peaks are impossible to compare if we don't know if they happened in 74F or 48F. That's a huge difference in ambient conditions according to my experience.This intercooler is on my single turbo 1M -- not a Z4 -- and the ambient ranged from 48 degrees F to 74 degrees F. The IAT delta was the same regardless of ambient temp.
See edit to my earlier post. The 48 degree weather was 3 weeks earlier at Summit Point. Following is info from the three days I just spent at VIR.Please post your ambient temps and conditions (preferably a log that also shows driving) for each data point (7.5 vs 7). Especially coolant peaks are impossible to compare if we don't know if they happened in 74F or 48F. That's a huge difference in ambient conditions according to my experience.
What fuel are you running? What coolant are you running? What oil? I think if we're going to start talking about all of this stuff, it'd be best to paint the full picture to notice possible successful methods. Any vids?See edit to my earlier post. The 48 degree weather was 3 weeks earlier at Summit Point. Following is info from the three days I just spent at VIR.
Session 1: Ambient 63 - Peak IAT 125 (+62) Coolant 205
Session 2: Ambient 68 - Peak IAT 127 (+62) Coolant 209
Session 3: Ambient 70 - Peak IAT 135 (+65) Coolant 206
Session 4: Ambient 74 - Peak IAT 136 (+62) Coolant 201
Session 5: Ambient 76 - Peak IAT 136 (+60) Coolant 196
Session 6: Ambient 77 - Peak IAT 133 (+56) Coolant 198
Each session 20-25 minutes on VIR Full Course. Max 24 psi boost.
93 octane. Distilled water with MoCool. Motul 300V 5W30.What fuel are you running? What coolant are you running? What oil? I think if we're going to start talking about all of this stuff, it'd be best to paint the full picture to notice possible successful methods. Any vids?
Thanks Neil.93 octane. Distilled water with MoCool. Motul 300V 5W30.
Coolant and oil type doesn't really matter if you ask me. I tried it all. Again the M4 is fine all stock. What we are clearly seeing here is inconsistent driving, which is understable at a common track day. There might be traffic, yellow flags, brake wear etc that plays into it. We need full logs to be sure. I will try to group the data anyway in a sec.What fuel are you running? What coolant are you running? What oil? I think if we're going to start talking about all of this stuff, it'd be best to paint the full picture to notice possible successful methods. Any vids?
Yeah for iat it makes sense. But you mean the GTX is easier on the the coolant as well? Is that a fact I missed somehow? Maybe @[email protected] could comment?Asbjorn -
I suspect my single turbo (GTX3576r) heats things up a lot less than your twins.
FWIW, I also have Swaintech White Lighning on my downpipes and manifold and a vented hood. I was also running with my MHD tune set to its coolant track mode.
Here are some logs at Buttonwillow Raceway. Typical warm days with insane temps.Let me chime in here...
@Asbjorn... First, the previous intercooler on the 1M was not a VRSF 7.5. It was a custom intercooler made by a turbo shop. So you can remove that data point from your chart above to prevent confusion to other readers. Second, the E89s have a nautical mile of distance between the intercooler and the air inlet of the front bumper. The E82s do not. Extremely large intercoolers on E82s get airflow blocked by the front bumper/bumper support leading to heat soak of a large % of the heat exchanger when subjected to long term heat management such as track driving. You can get away with it street driving and on the drag strip because it is short term heat management. This is why track guys have to ignore magical dyno data with all this stuff.
As for single vs twin turbo heat... yes when comparing apples to apples it makes sense. But we aren't comparing apples to apples. You have to take into account boost levels and other things. The best way to definitively answer whats going on is to have a pre-intercooler analog sensor logging temps. Can't do that with MHD, has to be done with an analog input capable data logger. Until then it is speculation. In other words, whats the pre-intercooler air temp of twins at ~15 PSI vs a single at ~24 PSI? Don't know until you log it. As you said, Chris at Vargas would be a good person to chime in on this.
As for cooling, its been determined already that regardless of what mode (stock settings or MHD track mode) the DME is trying to target 194 during high throttle/power demand. So ambient 68F with coolant temp of 209F versus ambient 77F with coolant temp 198F is an indication of deviation of average throttle % between the two sessions. The best way to do the comparison and get the full picture would be to do a histogram of throttle % between the two sessions. Can do via excel with an exported MHD log or (sorry to beat a dead horse) one click of a button with a true racing data logger system.
The fact that the DME is trying to target 194F and the coolant temp reached 209F with ambient 68F indicates to me the cooling system is insufficient to meet the demands of track driving. Once ambient temps get into the high 80s with moderate to high humidity I will be curious to see what the coolant temps will be. We patiently wait.
Finally, the turbos do have coolant running through them, not just oil. The N54 is all integrated into one system therefore turbo heat adds to the overall heat of the cooling system. Someone correct me if i'm wrong but the S55 has two cooling systems, a mechanical pump for main engine cooling and a separate electric pump system for turbo cooling. This indicates to me that it is significant additional heat and BMW wanted to combat that. Again someone please correct me if I'm wrong, not familiar with the S55 motors in detail.
I've added this data above, assuming 100F ambient. Thanks for the data point.Here are some logs at Buttonwillow Raceway. Typical warm days with insane temps.
91 Octane, Red Line 10w40, OEM coolant with water wetter (I know... Will change to distilled water once the body work is done)
Stock turbos, stock location silicone inlets, VRSF Race FMIC, CSF Radiator, custom twin Setrab oil cooler with no thermostat.