Heat problems on track: TECH. Read before adding an oil cooler!

[ITGUY]

I'm just curious. What are your IAT temps like blocking most of the front of the grill? Why not make an oil cooler on one of the side Fog light openings?

 

[DerHase]

I'm just curious. What are your IAT temps like blocking most of the front of the grill? Why not make an oil cooler on one of the side Fog light openings?

@Redslaya 's car has zero perceptible difference (all within noise of variance for track layout, etc) vs other cars as far as IAT goes on track.

For reference what I'm referring to:
Redslaya's car with the oil cooler and duct when tested at Palmer:

Vs the Black Cat Racing sample at Road Atlanta - same intercooler, same main radiator, same turbo:

The 2 deg diff in IATs is negligible when comparing all other samples, and because Palmer is way less WOT vs Road Atlanta (note the big difference in TPS % and top speeds), I'm sure that they'll be even closer when he gets back to VIR.

If you look at my samples (Derhase 2 and 3) - those are on two different tracks, same car. The smaller/windier track (Summit Jefferson) produces higher IATs - less time is spent on throttle, so the IATs will creep up when in the corners or coasting, etc. Tuned and untuned isn't a huge difference in IATs overall from the looks of it (I'm sure if we get some samples with big hybrid turbos then it might start to show up more).

Realistically any given temps can be taken as +/-5F accuracy, especially when it comes to IATs. If I didn't know that the car had a ducted oil cooler (and oil temps weren't shown), you'd have no way of knowing it was there.

I suspect on the topic of airflow, that these cars are just not moving a lot through the cooling stack. I REALLY want to get a car in the wind tunnel at some point. Would answer a lot of questions.

ALSO, looks like Jeff got a hold of a CSF radiator. Externally it flows 20% more air which I wasn't expecting. The unclear results (especially on nearly stock cars like @q74 's first sample) seem to indicate that whatever benefit *might* be there is not immediately obvious. I've been having everybody log coolant outlet temp on Simos Tools ever since I figured out it can be added in Mode 22.

https://mygolfmk7.com/2023/09/csf-radiator-external-airflow-test/

For the few cars that have logged it (including @Redslaya ), coolant outlet temp is essentially within 7F of engine coolant temp at any given time as soon as you're on track for more than 2 minutes (if that, more like 100 seconds, see the screenshot below). Most of the stock radiator cars lower the coolant temp by 8-10F for comparison. His car isn't a good direct comparison to any others (for coolant outlet temp specifically) because he has the oil cooler doing a lot of the heavy lifting, and again it really needs re-evaluated at VIR for coolant temps overall.

As always, more samples/testing is needed.

*le sigh*

 

[tigeo]

@Redslaya 's car has zero perceptible difference (all within noise of variance for track layout, etc) vs other cars as far as IAT goes on track.

For reference what I'm referring to:
Redslaya's car with the oil cooler and duct when tested at Palmer:

View attachment 290739

Vs the Black Cat Racing sample at Road Atlanta - same intercooler, same main radiator, same turbo:

View attachment 290754

The 2 deg diff in IATs is negligible when comparing all other samples, and because Palmer is way less WOT vs Road Atlanta (note the big difference in TPS % and top speeds), I'm sure that they'll be even closer when he gets back to VIR.

If you look at my samples (Derhase 2 and 3) - those are on two different tracks, same car. The smaller/windier track (Summit Jefferson) produces higher IATs - less time is spent on throttle, so the IATs will creep up when in the corners or coasting, etc. Tuned and untuned isn't a huge difference in IATs overall from the looks of it (I'm sure if we get some samples with big hybrid turbos then it might start to show up more).

Realistically any given temps can be taken as +/-5F accuracy, especially when it comes to IATs. If I didn't know that the car had a ducted oil cooler (and oil temps weren't shown), you'd have no way of knowing it was there.

I suspect on the topic of airflow, that these cars are just not moving a lot through the cooling stack. I REALLY want to get a car in the wind tunnel at some point. Would answer a lot of questions.

ALSO, looks like Jeff got a hold of a CSF radiator. Externally it flows 20% more air which I wasn't expecting. The unclear results (especially on nearly stock cars like @q74 's first sample) seem to indicate that whatever benefit *might* be there is not immediately obvious. I've been having everybody log coolant outlet temp on Simos Tools ever since I figured out it can be added in Mode 22.

For the few cars that have logged it (including @Redslaya ), coolant outlet temp is essentially within 7F of engine coolant temp at any given time as soon as you're on track for more than 2 minutes (if that, more like 100 seconds, see the screenshot below). Most of the stock radiator cars lower the coolant temp by 8-10F for comparison. His car isn't a good direct comparison to any others (for coolant outlet temp specifically) because he has the oil cooler doing a lot of the heavy lifting, and again it really needs re-evaluated at VIR for coolant temps overall.

As always, more samples/testing is needed.

*le sigh*

View attachment 290758

I didn't think about IATs in relation to smaller tracks with more off-throttle time when the IATs creep...maybe that's part of the reason my IATs seemed higher than I would have thought at Dominion which is small.

 

[ITGUY]

@Redslaya 's car has zero perceptible difference (all within noise of variance for track layout, etc) vs other cars as far as IAT goes on track.

For reference what I'm referring to:
Redslaya's car with the oil cooler and duct when tested at Palmer:

View attachment 290739

Vs the Black Cat Racing sample at Road Atlanta - same intercooler, same main radiator, same turbo:

View attachment 290754

The 2 deg diff in IATs is negligible when comparing all other samples, and because Palmer is way less WOT vs Road Atlanta (note the big difference in TPS % and top speeds), I'm sure that they'll be even closer when he gets back to VIR.

If you look at my samples (Derhase 2 and 3) - those are on two different tracks, same car. The smaller/windier track (Summit Jefferson) produces higher IATs - less time is spent on throttle, so the IATs will creep up when in the corners or coasting, etc. Tuned and untuned isn't a huge difference in IATs overall from the looks of it (I'm sure if we get some samples with big hybrid turbos then it might start to show up more).

Realistically any given temps can be taken as +/-5F accuracy, especially when it comes to IATs. If I didn't know that the car had a ducted oil cooler (and oil temps weren't shown), you'd have no way of knowing it was there.

I suspect on the topic of airflow, that these cars are just not moving a lot through the cooling stack. I REALLY want to get a car in the wind tunnel at some point. Would answer a lot of questions.

ALSO, looks like Jeff got a hold of a CSF radiator. Externally it flows 20% more air which I wasn't expecting. The unclear results (especially on nearly stock cars like @q74 's first sample) seem to indicate that whatever benefit *might* be there is not immediately obvious. I've been having everybody log coolant outlet temp on Simos Tools ever since I figured out it can be added in Mode 22.

For the few cars that have logged it (including @Redslaya ), coolant outlet temp is essentially within 7F of engine coolant temp at any given time as soon as you're on track for more than 2 minutes (if that, more like 100 seconds, see the screenshot below). Most of the stock radiator cars lower the coolant temp by 8-10F for comparison. His car isn't a good direct comparison to any others (for coolant outlet temp specifically) because he has the oil cooler doing a lot of the heavy lifting, and again it really needs re-evaluated at VIR for coolant temps overall.

As always, more samples/testing is needed.

*le sigh*

View attachment 290758

Interesting, thanks for the graphs. Has anyone eliminated the rear fan shroud? It would seem a lot of airflow could be gained if you just mounted 2 fans instead of using the fan shroud.

 

[tigeo]

I'm just curious. What are your IAT temps like blocking most of the front of the grill? Why not make an oil cooler on one of the side Fog light openings?

I thought the same thing but the data show a different story which was surprising....I mean, you have that huge-ass bumper etc. and upper grilled that nearly blocks all flow...amazing these cars run at all ahhahaahahah

 

[tigeo]

Interesting, thanks for the graphs. Has anyone eliminated the rear fan shroud? It would seem a lot of airflow could be gained if you just mounted 2 fans instead of using the fan shroud.

For sure but then you have to drive aroudn town when it's 95 out and your cooling efficiency has to be worse in those conditions...all a trade off with a daily that sees track use.

 

[DerHase]

Interesting, thanks for the graphs. Has anyone eliminated the rear fan shroud? It would seem a lot of airflow could be gained if you just mounted 2 fans instead of using the fan shroud.

That is actually something in the works. The Black Cat Racing sample actually has a gutted stock fan shroud.

I have a spare fan shroud that I'll be doing the same to as well.

Racelouvers has some "ok" data published showing why shrouds are bad for high speed track driving - would be WAY better if they removed a shroud from the one car rather than use two different vehicles, but it sums up the basics:
https://racelouvers.com/content/Race-Louvers-Fan-Shroud-Wind-Tunnel-Data.pdf

If overdone there could be a risk of overheating in traffic, but due to the cooling system on these cars I don't think it's nearly as much a concern as if it were a simple fixed pump and "dumb" thermostat. These things have several rotary valves inside the cooling module that can open or close as necessary. To bring the car up to temp quicker, it actually completely closes off so that coolant stays "still" in the block and can get warmed up fast. Then it slowly lets more and more through so as to not "shock" the block with cold coolant (potentially warping the head, etc).

This is a very well done video on how the cooling system works if you have an hour to kill:

 

[MonkeyMD]

For those that run FMIC, do you leave the stock one in it's location?

Just asking because I wonder how much running a FMIC and removing Stock one would help coolant temps

 

[ITGUY]

I used the ECS delete kit to get rid of mine, but I don’t know how it compares to keeping the IC with the FMIC. I did it from the start. I think it doesn’t make much difference for everyday driving. I would assume that removing it would be more advantageous on the track than leaving it in.

 

[MonkeyMD]

Found the solution guys.

https://www.tiktok.com/t/ZT8MLJup4/

 

[Redslaya]

It's been a while, but @DerHase and I should be doing final validation testing on the cooler duct next weekend at VIR. Anecdotally i had the car out at NCCAR a few weeks ago and saw no drop in vMAX as the session went on. Oil temps stayed consistently low (mid 230s).

 

[Redslaya]

I'll leave the full analysis to @DerHase , but I made it back to VIR this past weekend and was able to collect data with the duct installed. While ambient conditions were slightly cooler (8°F) and average TPS was slightly lower (~2.5%) It appears safe to say the duct has fixed the issues introduced by the oil cooler. Average IAT delta was down 33.79°F, coolant temps dropped an average 18.64°F, and I gained 9MPH on the 4000ft back straight. I'll note that no 'spoiler' was installed infront of the duct exit, it was just the simple hole cut in the bottom of the bumper for air to exit from.

 

[DerHase]

Link to final testing here for future reference:
https://www.datadrivenmqb.com/drivetrain/oil-cooler-duct-conclusionresults

Traffic in his run group kinda sucked for getting good data (and you can see the slow down going through the climbing esses)... but bottom line his car is doing 8-9mph faster down the back straight now like an IS38 car should be doing. It really doesn't get a whole lot more conclusive than that. I think 133 or 134 is the fastest I've seen in any of his prior logs for reference.

 

[tigeo]

Link to final testing here for future reference:
https://www.datadrivenmqb.com/drivetrain/oil-cooler-duct-conclusionresults

Traffic in his run group kinda sucked for getting good data (and you can see the slow down going through the climbing esses)... but bottom line his car is doing 8-9mph faster down the back straight now like an IS38 car should be doing. It really doesn't get a whole lot more conclusive than that. I think 133 or 134 is the fastest I've seen in any of his prior logs for reference.

View attachment 296485

What about oil temps?

 

[Redslaya]

Due to the original log having the modeled oil temp instead of the true oil temp it was excluded from the charts. However on the dash i never saw anything about 235°F.