Calling all N54 Track Junkies: The N54 Track Temp Management Thread

[thisisluka]

Hey y'all - in the process of building my 135i club sport / track tool project, I've known about, and run into just about all of the fun temperature management games that need to be played with these things when pushed hard on track.

I want to dive in beyond the basics for track use, and focus more towards advanced, or uncommon methods and optimizations for heat management. First post might be a bit of a long one, but wanted to kinda get out all the ideas & info I had.

I've had some theories and questions I really couldn't find too many answers to, and I wanted to ponder to the guys that are really pushing their n54's hard on track before testing and doing a few myself, and hopefully start a thread to keep all the info and data in one place, to help others in the future trying to tackle the same.

The car is currently being used for HPDE + time trials in SCCA Max 1 group in my local Chicago chapter, with the goal to eventually run as many time attack events I can afford, and be competitive running in SCCA nationals / Gridlife / Global Time Attack / NASA next season. It's not a dedicated track car, but the philosophy is to be able to drive to and from events no matter how far away (with a spare set of wheels / tires if its a true hike) and still be able to enjoy it on the weekend on backroads or take the girlfriend for an ice cream. I know this has its own compromises, but I'm willing to make them.

In the process of making a full build thread, but cooling wise, my setup consists of CSF Racing Rad w/ distilled water & 2 bottles of water wetter, MHD Track Coolant targets & "Max Cool" when on track, Trackspec e92 M3 Center Hood Louvre, VRSF 1k Race 7.5" HD IC, 185º Oil Cooler Tstat, Dual 25 Row Oil Coolers w/ custom 10AN lines/fittings with shrouding and my fender well guards cut with mesh to allow ample airflow & protect from rocks. Also running Rotella 5w-40 if that makes a difference to anyone.

Now, getting into it:

For starters heat wrapping and insulation: gold foil or heat wrap around the downpipes / inlets / outlets / coolant lines (mainly stuff around the hot side of the motor near or around turbos). Has anyone seen any worthwhile effect in this ballpark? Area gets warm to say the least, and I can only imagine, especially with how hot the stock twins get, that some sort of insulation could contribute towards a respectable delta.

Secondly, has anyone seen any temp benefit of relocating the coolant reservoir? I know this is a double edged sword, since most that do are running hot side inlets, which means the potential for hotter pre-turbo IAT's if not heat shielded or ducted properly. However, the idea of moving that big plastic bottle of coolant as far away from the turbos sounds like a good idea.

E85 usage: Of the 4 events that I've competed in this year with the car, I've been on stockers w/ 93 pump gas running the OTS MHD v10 Stg2+, and have generally been ok avoiding limp mode, in addition to running the heat on max to take off some temp from the heater core after a few hot laps. Didn't have the time to shake down the car on any e85 maps between the other stuff it needed before each race or track day, but have heard from a few friends that this also assisted in mitigating temps for them on different platforms.

Lastly, upgraded turbos: In a perfect world, would love to run a log twin scroll manifold and a spicy single turbo knowing that doing so would help temps while being able to run a hearty amount of power, but realistically going to be looking towards running hybrids or larger upgraded twins to keep cost & complexity down, and spool time / responsiveness up. I've seen a thread or two with success of an Australian 335i endurance race car running upgraded RB's, but no idea what sort of power they're pushing due to classing and what I can only imagine would be endurance reliability / longevity. Ideally, I'd like to be in the ballpark of 500-550whp/wtq on an e85 map, give or take 50whp for temp / reliability sake with an optional on the fly kill tune for when on a hot lap or two when the competition ramps up.

Thanks for bearing with my short bible on n54 shenanigans, eager to hear what any of you think or have to offer!

[gmx]

Which 335i's are you referring to? Endurance has completely different set of rules which indirectly influence temp management. For more power as well as keeping thermals in check, single is the answer.

[amg6975]

If you want to chase small improvements and you're not having brake temp issues, maybe try blocking off the ducts through the bumper to create more pressure on the front of your oil coolers and lower the pressure in the wheel well?

See if DO88 makes a radiator and ditch the CSF? More hood vents? Remove or replace the A/C condenser?

[thisisluka]

Originally Posted by gmx

Which 335i's are you referring to? Endurance has completely different set of rules which indirectly influence temp management. For more power as well as keeping thermals in check, single is the answer.

See link attached below, post #29, by Rob at RB, is what I was referring to.

https://www.e90post.com/forums/showt...1482705&page=2

Originally Posted by amg6975

If you want to chase small improvements and you're not having brake temp issues, maybe try blocking off the ducts through the bumper to create more pressure on the front of your oil coolers and lower the pressure in the wheel well?

See if DO88 makes a radiator and ditch the CSF? More hood vents? Remove or replace the A/C condenser?

Interesting point on the fender ducts. I thought having more airflow, over higher pressure to the cooler, would be more effective. Easy to test tough, and would be willing to give it a shot. Planning to chop more trackspec louvres into the fenders, but am going to wait until next season, since the plan is to install all OEM 1M body bits this winter while she's hard parked. Not much of a point of doing it twice, and not too many events left this season anyways being limited by midwestern weather here in Chicago.

I've seen a load of S65 guys jumping ship to DO88, but no idea wether it's a worthwhile vs a lateral move over CSF for the N54. Do you know any details or have experience on why/how theirs is superior?

I think I've seen some posts mentioning you've done an S65 swap - super cool. Curious to hear if you've run into any cooling or reliability issues on track? Have a pipe dream long term to do the same.

Replacing the condenser would be another good idea. Thing has a healthy amount of miles on it, could imagine enough bent fins would inhibit the radiator from doing as good of a job as it could.

[gmx]

I'll split this up and start off with the good first. Definitely have the right philosophy in getting thermals fairly under control rather than chasing bulk power then chasing your tail after.

Originally Posted by thisisluka

Interesting point on the fender ducts. I thought having more airflow, over higher pressure to the cooler, would be more effective. Easy to test tough, and would be willing to give it a shot. Planning to chop more trackspec louvres into the fenders, but am going to wait until next season, since the plan is to install all OEM 1M body bits this winter while she's hard parked. Not much of a point of doing it twice, and not too many events left this season anyways being limited by midwestern weather here in Chicago.

I've seen a load of S65 guys jumping ship to DO88, but no idea wether it's a worthwhile vs a lateral move over CSF for the N54. Do you know any details or have experience on why/how theirs is superior?

I think I've seen some posts mentioning you've done an S65 swap - super cool. Curious to hear if you've run into any cooling or reliability issues on track? Have a pipe dream long term to do the same.

Replacing the condenser would be another good idea. Thing has a healthy amount of miles on it, could imagine enough bent fins would inhibit the radiator from doing as good of a job as it could.

In the imgur album of probably the most successful 1M/N54 car (imgur.com/a/qMrpY7g), there's PWR coolers used between various rounds such as whether it's an endurance or sprint rd. Lower budget teams would just use one configuration or other brands (China, or better mocal/setrabs etc). Make sure you build larger ducts for them. A 1M duct for example, only covers about 12-13rows or so.
There are certain scope limits to my build (no cutting) and I go through brakes a lot. Since I don't want to add minor aero like lips, which would also be against APC rules, I have thought about 3d scanning/printing a custom oil cooler duct + brake duct all in one. Duct and shroud the core. Have an air guide that splits the bumper air dam feeding a hose into the wheel well with a traditional backing plate coupler. I think the 135i duct is in principle already like this.

Originally Posted by thisisluka

See link attached below, post #29, by Rob at RB, is what I was referring to.

https://www.e90post.com/forums/showt...1482705&page=2

Kind of what I was getting to, that quote suggests they were happy to blatantly cheat in the APC. Even though it's a long time ago now, I would be curious to see if it was actually them that said that or one of the local fraudulent scammers that forged such words on behalf of the team with a vested interesting at the time. Aka reselling RB's (and Helix/DAW turbos etc) before then running away when shit went wrong as does often with aftermarket hybrid twins. 12hr had potentially different rules to the 6hr and it hasn't allowed production/grassroots cars for a long time now. For one, no slicks were ever AFAIK whereas that picture has it. 12hr is typically a GT event with different rules entirely.

As for APC, it's limited. Cannot fit larger turbos including ported housings or larger/aftermarket compressor nor turbine wheels. It's not a high budget category (well, the top F8x teams are close to spending GT4 levels now) so scrutineering each car to the finest detail will not be F1 levels. Inlets, airbox, outlets, nor intercooler footprint are allowed to be changed either hence why the PWR intercooler is the size it is [and expensive]. This indirectly does not limit airflow to the radiator. Something to be mindful of, with large aftermarket intercoolers. The only other tuning with control fuel is via other means. You can see the list of vehicle specific "BoP" here [for the current year]: https://ausprodcars.com.au/regulations/
The rules are of interest to me since their qualifying laptimes are the only available benchmark esp if done with a semi-pro/pro during a co-driving weekend round.

Here's a pic on initial build of probably the most successful N54 APC car:

They were later selling a set with coated turbine housings on ebay when moving to the F8x. That's all the development that went into it or was really left free. Exhaust wise, you could do whatever you wanted post-turbine housings hence the DPs pictured there.

[amg6975]

Originally Posted by thisisluka

Interesting point on the fender ducts. I thought having more airflow, over higher pressure to the cooler, would be more effective. Easy to test tough, and would be willing to give it a shot.

What I'm talking about are the "brake cooling holes" that are just inboard of your oil coolers. These will bleed high pressure air from the front air dam area into the wheel well. To increase the amount of airflow through your oil coolers you need to increase the pressure in front of them and decrease the pressure behind them. Blocking these off would do that. Whether it would make any difference or not, I have no idea.

Edit: Look back at the pictures I think you already eliminated these. It does look like there may be an opportunity to better direct the airflow in that area though.

Originally Posted by thisisluka

I think I've seen some posts mentioning you've done an S65 swap - super cool. Curious to hear if you've run into any cooling or reliability issues on track? Have a pipe dream long term to do the same.

Yeah my car is an S65. Way better at heat management than the N55 that was in it before. I was having some minor oil temperature issues but swapping from an OEM to a DO88 radiator and doing some internal air management of the oil cooler air stream really helped a lot. Now the only thing that's any sort of issue is the DCT will start to get a little lazy after 20-30 mins of hammering it on track. One cool down lap will get it right back though.

[thisisluka]

Originally Posted by gmx

In the imgur album of probably the most successful 1M/N54 car (imgur.com/a/qMrpY7g), there's PWR coolers used between various rounds such as whether it's an endurance or sprint rd. Lower budget teams would just use one configuration or other brands (China, or better mocal/setrabs etc). Make sure you build larger ducts for them. A 1M duct for example, only covers about 12-13rows or so.
There are certain scope limits to my build (no cutting) and I go through brakes a lot. Since I don't want to add minor aero like lips, which would also be against APC rules, I have thought about 3d scanning/printing a custom oil cooler duct + brake duct all in one. Duct and shroud the core. Have an air guide that splits the bumper air dam feeding a hose into the wheel well with a traditional backing plate coupler. I think the 135i duct is in principle already like this.

That thing is a proper build. The level of detail and construction of the fuel cell alone, to fit into the stock fuel tank location like it does, is so good. Do you know if they were running dual oil coolers or if they chose to run additional radiators instead?

Kind of like how amg6975 mentioned, having most of the pressure be directed to the cooler would likely maximize the coolers efficiency, so running a brake duct within the same space like the OEM 135i design might diminish that. A cool idea I wanted to run for higher speed tracks was utilizing NACA ducts on the underbody tray. I have all the parts but just need to get around to installing, but will be a bit of a challenge as my chassis mounted splitter would cover up the ideal location for them. Post #44 in the thread linked below illustrates what I'm getting at. Worst case scenario, might just cut into the corners / ends of the splitter to make room for the NACA ducts. Was also thinking that they could be utilized in a split two output NACA duct on each side, one for brakes, one line feeding up to the engine bay out to the inlets for cooler air feed. Running a small bit of meth injection might be a more effective way to bring cooler IAT's into the equation though.

https://www.1addicts.com/forums/show...1030176&page=2

Originally Posted by gmx

Kind of what I was getting to, that quote suggests they were happy to blatantly cheat in the APC. Even though it's a long time ago now, I would be curious to see if it was actually them that said that or one of the local fraudulent scammers that forged such words on behalf of the team with a vested interesting at the time. Aka reselling RB's (and Helix/DAW turbos etc) before then running away when shit went wrong as does often with aftermarket hybrid twins. 12hr had potentially different rules to the 6hr and it hasn't allowed production/grassroots cars for a long time now. For one, no slicks were ever AFAIK whereas that picture has it. 12hr is typically a GT event with different rules entirely.

As for APC, it's limited. Cannot fit larger turbos including ported housings or larger/aftermarket compressor nor turbine wheels. It's not a high budget category (well, the top F8x teams are close to spending GT4 levels now) so scrutineering each car to the finest detail will not be F1 levels. Inlets, airbox, outlets, nor intercooler footprint are allowed to be changed either hence why the PWR intercooler is the size it is [and expensive]. This indirectly does not limit airflow to the radiator. Something to be mindful of, with large aftermarket intercoolers. The only other tuning with control fuel is via other means. You can see the list of vehicle specific "BoP" here [for the current year]: https://ausprodcars.com.au/regulations/
The rules are of interest to me since their qualifying laptimes are the only available benchmark esp if done with a semi-pro/pro during a co-driving weekend round.

Here's a pic on initial build of probably the most successful N54 APC car:
They were later selling a set with coated turbine housings on ebay when moving to the F8x. That's all the development that went into it or was really left free. Exhaust wise, you could do whatever you wanted post-turbine housings hence the DPs pictured there.

Fascinating, had no idea I was uncovering any drama haha. I know many racing leagues / organizations are very strict on modifications based on class, but definitely brings the level of the APC even more into light. Don't personally know much about the APC being based in the states, but sounds like it's full of intense competition.

The PWR stuff looks high quality but sheesh you're not kidding about how expensive they are. I'd imagine the F8X platform being far more competitive and capable given the higher baseline level of performance with a forced induction motor from factory. Regarding the larger IC, that's another thing I've been thinking about, given that it's great the VRSF's have a huge surface area (which contribute to their insane weight), but a majority of it is covered up behind the front bumper cover. Maybe might benefit cutting the bumper cover and implementing some shrouding on the higher end of the IC. I wonder how much of a difference the coatings on the turbine housings would make. Thankfully the classing I would fall in allow a lot more freedom, so could consider running turbo blankets & downpipe wrapping if theres anyone that even makes them for the smaller stock snails.

Originally Posted by amg6975

What I'm talking about are the "brake cooling holes" that are just inboard of your oil coolers. These will bleed high pressure air from the front air dam area into the wheel well. To increase the amount of airflow through your oil coolers you need to increase the pressure in front of them and decrease the pressure behind them. Blocking these off would do that. Whether it would make any difference or not, I have no idea.

Edit: Look back at the pictures I think you already eliminated these. It does look like there may be an opportunity to better direct the airflow in that area though.

Ah I understand what you're saying. Yes, as you mentioned those have been eliminated. Before driving to track I pull the fender well front plastic out, and make a flexible shroud out of aluminum tape from the bumper opening, connecting to the edges of the oil cooler, which ends up being one time use, more or less. I want to make a shroud either out of aluminum or plastic long term, but am waiting until this winter after transitioning to using the 1M body panels to have a more "final/permanent" setup. Ideally I'd also cut more louvres into the tops of the 1M fenders to bleed out that pressure from the wheel well, so hopefully the combo would be more effective per your advice. Thankfully don't have any brake overheating issues (yet) but ideally running the ducted GT4 front lip, or implementing a pair of NACA ducts in the underfloor tray as mentioned above would bring resolve when I eventually do.

Originally Posted by amg6975

Yeah my car is an S65. Way better at heat management than the N55 that was in it before. I was having some minor oil temperature issues but swapping from an OEM to a DO88 radiator and doing some internal air management of the oil cooler air stream really helped a lot. Now the only thing that's any sort of issue is the DCT will start to get a little lazy after 20-30 mins of hammering it on track. One cool down lap will get it right back though.

Love that for you, it's gotta be beyond a blast having that power plant in there! The sound alone I'd imagine is intoxicating. How's it feel on track with a bit less weight over the nose not having the N55 in there?

Are you using the S65 DCT or the DCT from the N55? I'm unknowledgable if they're different / fit up at all besides knowing that they're both DCT's. Have seen some users with the N55 DCT having similar issues even with an aftermarket cooler, is it worth adding further cooling or is it just a downfall of that generation of trans?

[gmx]

Dual oil coolers in series for most if not all the 1M racecars. I'm not 100% sure on the 335i/135i's but I'm pretty sure they went down the same path if not prior, then eventually. If memory serves me correct, one of the prototype PWR coolers was a brazed core servicing the original aux water pump and additional oil cooling capacity. But I can't find pics of it and didn't ask PWR.

They did run PWR main radiators though. There's two versions and I'm pretty sure they ran the slightly thicker race version. Might require AC condenser removal, I'm not certain on that. Some teams esp when it comes to endurance like to keep AC understandably there may have been compromises in this area. It's been years since I've talked to them but they're pretty good and happy to give engineering diagrams of different applicable part numbers.

[amg6975]

Originally Posted by thisisluka

Love that for you, it's gotta be beyond a blast having that power plant in there! The sound alone I'd imagine is intoxicating. How's it feel on track with a bit less weight over the nose not having the N55 in there?

Are you using the S65 DCT or the DCT from the N55? I'm unknowledgable if they're different / fit up at all besides knowing that they're both DCT's. Have seen some users with the N55 DCT having similar issues even with an aftermarket cooler, is it worth adding further cooling or is it just a downfall of that generation of trans?

It is a really, really good time on track, the sound is definitely one of the big perks and what everyone immediately notices. The predictability of the torque and slight advantage in weight distribution really makes a big difference. I dropped 6-7 seconds around Watkins Glen going from the N55 to the S65, with very similar top speeds.

The DCT is from the M3, the bell housing is different from the I6 engines to the V8. As far as I'm aware that and software is about the only difference. I'll probably try a finned aluminum pan before going nuts with coolers for it.

[gmx]

One thing to mention re shrouding/venting. Definitely worth seeing if the undertray is a possible vent spot like the newer cars with a rotated heat exchanger core (oil cooler?) placed. I think the vent there helps extraction and thus air through the oil cooler on those cars (F8x).
Don't know whether it can be straight copy pasted if at all, might be a home aero project worth investigating.

[tedg04]

Great thread, and quite timely as I'm working on temp management for my n54 e82 as well. I'll try more stuff out, but at present it appears I'm likely to need additional oil cooling.

[thisisluka]

Originally Posted by gmx

Dual oil coolers in series for most if not all the 1M racecars. I'm not 100% sure on the 335i/135i's but I'm pretty sure they went down the same path if not prior, then eventually. If memory serves me correct, one of the prototype PWR coolers was a brazed core servicing the original aux water pump and additional oil cooling capacity. But I can't find pics of it and didn't ask PWR.

They did run PWR main radiators though. There's two versions and I'm pretty sure they ran the slightly thicker race version. Might require AC condenser removal, I'm not certain on that. Some teams esp when it comes to endurance like to keep AC understandably there may have been compromises in this area. It's been years since I've talked to them but they're pretty good and happy to give engineering diagrams of different applicable part numbers.

Yeah sounds like standard N54 oil cooler setup with more efficient cores. That brazed core would be sick.

With the thicker race version, I don’t think it’d be a problem since from what it sounds like from regs, they were using stock inlets. Sock location silicone inlets would pose quite a problem there lol

Originally Posted by amg6975

It is a really, really good time on track, the sound is definitely one of the big perks and what everyone immediately notices. The predictability of the torque and slight advantage in weight distribution really makes a big difference. I dropped 6-7 seconds around Watkins Glen going from the N55 to the S65, with very similar top speeds.

The DCT is from the M3, the bell housing is different from the I6 engines to the V8. As far as I'm aware that and software is about the only difference. I'll probably try a finned aluminum pan before going nuts with coolers for it.

No kidding. That’s super impressive, damn near in the ballpark of big turbo + wide body level of improvement on times.

Ahh yes I totally forgot about the upgraded pans. iirc seems legit garage is track focused pans for the s55 DCT, would be curious how hard it would be to make one for similar use fot the s65 DCT, unless there’s a good / proven one out there already.

Originally Posted by gmx

One thing to mention re shrouding/venting. Definitely worth seeing if the undertray is a possible vent spot like the newer cars with a rotated heat exchanger core (oil cooler?) placed. I think the vent there helps extraction and thus air through the oil cooler on those cars (F8x).
Don't know whether it can be straight copy pasted if at all, might be a home aero project worth investigating.

That would be pretty cool, I think the biggest issue would be space limitations, esp on the 1’ers, space in that area comes at a premium. Also would be terrified if I bottomed out the car on track or came too hard over a curb stone and end up yeeting it to oblivion. Would def depend on placement / fitment though. The gents over at seems legit garage built a custom front clip out of tubular aluminum to replace the crash bar & connecting plastics behind/between it. Gave an immense amount of room to play with. Probably wouldn’t recommend following that path for a car that sees the street use for obvious safety reasons though.

Attached the vid below for ref, pretty sure this is the one.

https://youtu.be/5R3g_PUtW1k?si=ozVjx-qdlCNoXP5O

[amg6975]

Originally Posted by thisisluka

Ahh yes I totally forgot about the upgraded pans. iirc seems legit garage is track focused pans for the s55 DCT, would be curious how hard it would be to make one for similar use fot the s65 DCT, unless there’s a good / proven one out there already.

As far as I know all DCTs have the same pan. The only real difference in any of them is bellhousing bolt pattern, cooling, and software