Overheating on track

[btowery]

I’m a former IMSA racer, now Chief Instructor at Chin Motorsports the largest presenter of track days in the Southeast USA.

I regularly track my Mk5 TSI. I have modified it significantly; here’s the short list:
APR tuned K04, Milltek turbo back exhaust, Wagner intercooler, Carbonio intake, Whiteline bars and bushings, custom Ground Control coilovers (car is lowered 1" front, 1.5" rear), Setrab oil cooler, SSP DSG cooler, SSP Kevlar clutch pack, switch activated Accusump, OZ 17”x8.5" lightweight rims fitted with 235X45 R-spec tires. Further, I have disconnected the DSG from the engine cooling system.

The car is very quick. It’s great fun to regularly spank Porsche’s I see at the track, at least those piloted with negligible skills. However, temps begin to climb after about three hard laps, depending upon ambient. Five laps maxes me out even on a cool day. A review of the steps above will show that I’ve done a good bit to mitigate the heat.

It’s important to point out that I had the same problems before I mounted the K04. Sadly, I blew an engine. Comprehensively. I trashed the turbo along with the rest of the motor. I replaced it with the K04, pairing it with the Wagner intercooler.

Having added the oil cooler before the catastrophe with the first engine, we reasoned that the DSG was making too much heat for the cooling system to handle. I added the DSG cooler. Still made big temps. I disconnected the cooling link between the engine and the tranny. Nada. Next—theorizing that slipping clutches could be the culprit—we installed the Kevlar clutch pack, which immediately proved to be a great performance booster. I was anxious to get to the track to prove the idea that the slipping clutches—now an established fact—were responsible for the overheating.

I recently took that package to Barber Motorsports Park to test the current theory. Three laps: oil temp reaching for 250, water temp approaching the red zone, I cursed and ran a cool-down lap. This, by the way, on a wet track (ambient temp 60 F).

Fortunately, while I was there, I was able to speak with a factory VW engineer about the problem (he is based in Chattanooga, only a couple of hours from that fabulous track). He believes that it is likely caused by oil cavitation in the pan and recommended a baffled unit with some type of trap around the pickup. I have identified and ordered a Wortec aluminum pan—the only unit I’ve found that seems to fit the bill.

Through forums and emails, I am circling the globe looking for others who’ve had similar experiences, in hopes of finding other possible solutions and sharing what I’ve learned, which—clearly—is not much. I look forward to hearing from you.

[dansmith180]

Water meth injection is very good for keeping intake and therefore engine temps down, also getting more air into the engine bay would probably help a bit, bonnet scoop/ grills etc open fog grills and removing the under bonnet insulation.

[Dan_FR]

A/C rad removed? rad in good condition?  Thought of removing some of the shroud around the fans that reduce air flow through the rad? Any way for the heat to escape the engine bay or does the bonnet still have its seals and the undertray in place etc.?

[xjay1337]

Something must be wrong. in my years of hooning I've never once had the water temperature display over 90 degrees.
Oil temps I've seen high 100's (107/108).

something must be wrong for it to overheat that quickly. have you tried basic stuff like new thermostats, new cts? all genuine bits. any restrictions to the rad for air flow?

[btowery]

All above suggestions are good, thanks. I am opening grills (i.e., I’ve ordered some that are open), otherwise good under-hood air-flow already established. Probably would help to get more air moving under the hood; however, the VW theory is that good air flow over and under is established by having the hood without vents, following the low pressure behind the engine and under the car. I’m not convinced that it’s effective, but I’ve been reluctant to swim against this advice.
The A/C condenser is still in place. Stupid, I know. I’m still pretending this is a street car. It’s hot down here.
Have only begun to contemplate water/meth injection. I have been led to believe this would compromise the tune. I’ve chased after tunes endlessly in the past and am not interested in getting back into that orchestra pit, preferring to leave the conducting up to APR.
Yes, all the basic stuff has been and is checked on a routine basis. All this head-scratching requires it.
Thanks, again, to each of you for the input.

[dansmith180]

Might be silly but if your waters getting that hot could there be a problem with your fans? I've never had mine go above 90. Also what oil are you using? I would reccomend Millers Nanodrive as its designed for race use and does normally keep a few degreed cooler than other oils. I doubt water meth would harm your tune, its has huge cooling benefits that you obviously could use.

[Dan_FR]

You do not need to tune for Water Meth at all, it can be used for safety and cooling in terms of lower charge temp and a higher resistance to knock. Don't expect it to work wonders and make your engine run that much cooler though. You could just run water instead, it'll be like driving your car on a cold damp day (we all know how much better a car feels on one of these days)

If it's a track car then ditch the Air con, check the fins in your IC and rad and make sure they are in pretty good condition. Ruled out the thermostat not doing it's job properly?

What VW theorey are you describing? VW set the car up to be a road car designed to cope with the much lower level of heat produced when running standard power. Ultimate cooling was not high upon the list when considering airflow on the Mk5.

[btowery]

    Yes, regularly check all the simple stuff like pressure cap. Radiator carefully inspected recently, while installing new air-con condenser, which was pretty gnarly. Installed a mesh stone guard in the grill at that time.
    I'm well aware of the advantages of removing the air-con. However, this is a compromise car. I drive it to the track regularly: back seats removed, I've built a platform for the rear compartment that removes at the track and makes into a table (the legs store in the platform). I can get four spares, canopy, tools, track paraphernalia, and my personal gear into the car. It's a great set-up. Nearing 70, myself, I'm unwilling to give up the ease of travel the package affords me. And unwilling to make these trips across the Southeastern US without air conditioning. To this degree, you can certainly say, "What does the old guy expect?" Well, I'm stubborn. I want the system to work just as I've got it set up. And not overheat.
    Again, I'm interested to look into the water/meth injection. It could well be helpful. However, when last at Barber, I was in the rain--mid-60s F. Overheated chasing a full race GTi (one prepped for the World Challenge series). Almost kept up for a couple of laps, giving away only a couple of tenths per lap. Until his race rains began to come in. By that time, I was watching the temps creep up, as well. There was a lot of water on the track. Definitely getting the full wet-day engine experience. (All shifts managed in DSG Manual mode; shift point at top of torque curve, no redlining.)
    As to the 'theory' of which I spoke, this came directly from a VW engineer, who insisted that there was good air-flow through the engine bay that would be compromised by vents like those popularly installed in modified hoods. As I said, I'm not convinced that this was good information--even from the horses mouth, as it was.
I do appreciate the input.
Thanks.

[xjay1337]

All above suggestions are good, thanks. I am opening grills (i.e., I’ve ordered some that are open), otherwise good under-hood air-flow already established. Probably would help to get more air moving under the hood; however, the VW theory is that good air flow over and under is established by having the hood without vents, following the low pressure behind the engine and under the car. I’m not convinced that it’s effective, but I’ve been reluctant to swim against this advice.
The A/C condenser is still in place. Stupid, I know. I’m still pretending this is a street car. It’s hot down here.
Have only begun to contemplate water/meth injection. I have been led to believe this would compromise the tune. I’ve chased after tunes endlessly in the past and am not interested in getting back into that orchestra pit, preferring to leave the conducting up to APR.
Yes, all the basic stuff has been and is checked on a routine basis. All this head-scratching requires it.
Thanks, again, to each of you for the input.

You still haven't answered the question.

Have you replaced the thermostat and the coolant temperature sensor with new genuine parts?
are there any thermostats which open at a lower temperature?
have you flushed the cooling system with fresh g12/g13?
use a suitable oil for race use, millers nanodrive cfs 5w40 knocked 10-15 degrees off my oil temps vs regular 5w30 stuff.

overheating is NOT normal and I have never seen my engine water temps over 98 on the polar (still 90 degree on the gauge).
The car shouldn't over heat and you don't need to remove the AC condensor.
Something is wrong with the cooling system in your car.

[btowery]

You're right, I didn't answer your question directly. Did say that I'd done all the easy stuff. I've changed thermostat and temp sensor twice. Have run various water solutions, trying Redline water-wetter and others--now running conventional VW coolant, again. It's a catless car: I've been using Royal Purple race formulated oil.
    What you said is what I've continued to maintain, "Something's wrong with the cooling system."
    We just can't find it.

PS--noticed your interesting post about wheel and tire fitments. I added to my description of my car, above, that I'm running 235X45 tires on 17X8.5 rims.

[xjay1337]

I see, cheers for clarification :)

Sorry, just often you get a lot of people who say "Yes i've done all the easy stuff". then say "new thermostat fixed the problem".

Have you changed the secondary/tertiary thermostats too? GTI's have 2, DSG's have 3 , but you seperated the cooling circuit.
Very weird and frustrating issue. Have you replaced the rad incase of any internal damage? Waterpump all good?

[btowery]

I appreciate your continuing to focus on this problem with me.

This is an issue that predates this engine. It's a pernicious history.
I had a similar set-up on a previous engine (minus the Wagner inter-cooler and with the DSG still connected to the engine cooling system but with the SSP cooler). The car would overheat after half-dozen hard laps.
On a day with temps in the mid-90s F, down a long straightaway, I noticed heat beginning to climb but within tolerances. Following the straight, are a series of turns ending with heavy braking from 100+ into a long, g-loaded carousel that exits to the long, front straight; the engine imploded on that straight. I believe that the problem was caused by the inability of the motor to sustain oiling under heavy g-loading.

New engine (VW reman), new OEM radiator, new K04, the Wagner. I also added the pressure actuated Accusump at that point: hoped it might ameliorate the heating but mostly for insurance against the starvation that I visualized happening to the rear bearings.

I feel fortunate to have made the acquaintance of the VW engineer about whom I spoke in a previous message, who confirmed my assessment of the oil starvation problem. He, as I mentioned, said that he believed the problem was probably oil cavitation and the associated compromise of the pickup. The Wortec oil pan is the only option I've found to address that problem. However, it really only has a single, feeble little fence to try to capture the oil supply--no real additional baffling to limit the cavitation in the pan. Perhaps the additional oil volume will help. Maybe the finned, aluminum construction will dissipate some heat. Very iffy.

I don't know that we've changed the tertiary thermostats. Must confess that I didn't know about them. I'll have my mechanic do so when he installs the oil pan. (Even as an old fart, I'm a reasonably quick driver and--I'll boast--a good instructor but have always been a piss-poor mechanic.)

Would also like to replace the stock radiator with the Forge unit but can't handle the tariff at the moment.

As you can tell, all very frustrating.

[teo_parvu]

My friend @fuscobal had the same problems.
The only solution was to replace the S3 intercooler+Forge Twintercooler with the bigger THS one.
It seems that the Forge Twintercooler (which looks similer with Wagner) was blocking the airflow to the water radiator.

[xjay1337]

That would make sense as it blocks a lot of the airflow.
Wi also cool better with a ths one alone i imagine.  Stock ic is restriction, twintercooler on stock ic will just add lag.

[fuscobal]

Btowery, I've had serious overheat problems inthe past on my GTI (k04 with 380HP, 500NM). After several hard laps, just like you, my water temps were reaching 130degC and the stop now message appeared on my dash. I've also blown a water plastic hose, lost all coolant and damaged the engine. At that time, I had the 3 pack radiators (S3 intercooler, oem water cooler and oem oil cooler) + the Forge IC on front. Air temps were 10degC over the ambiental which was quite good but water kept boiling. While reworking my engine, I decided to solve that problem forever.

1) First of all, I replaced the Forge + S3 with the THS IC installed on the OEM position to keep the flow as close to OEM as possible as I suspected Forge was somehow blocking some of the flow to the water rad. By doing this, the air temps were even better with only 5 more than ambiental

2) Since my air con compressor was gone anyway, I' ve removed the entire system, including the radiator and pipes, which brought me a 15kg weight saving and a cleaner engine bay. While removing the rads, I've noticed the water rad was shot on the face hidden by the 2 fans so couldn't be observed before. This probably allowed air into the system which probably contributed to the high temp. After this second measure, I had only 2 radiators left instead of 4 and engine throttle response improved also from removing the aircon

3) Third measure was to remove fog lights and install the oem small aditional water radiator on the driver's side which is receiving direct airflow being positioned pow and directly behind the fog light hole, with a plastic deflector that forces all air that enters the hole to pass through it.

Since these 3, my water temps on the track didn't even get past 85-86degC instead of 130+ before. No matter how hard I drive, my temps are constant through a 20mins track session.

Back to your problem now. I'd say to check the following :

- the measures you've taken to cool the engine might do the opposite in a way that you can't realise.
- rads or sensors not working properly
- fault in the software. What software do you use and did u install the latest update ? Is it adjustable from the user's side ?