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Is the stock cooling system adequate for track day in the heat?
I just bought a 2005. Engine is stock except for pulley and catback. In the summer some of the tracks around here get ambient temps around 100f. Will the stock system work, or do I need a larger radiator or anything else?
I just bought a 2005. Engine is stock except for pulley and catback. In the summer some of the tracks around here get ambient temps around 100f. Will the stock system work, or do I need a larger radiator or anything else?
Will depend on a lot of things....the track layout, how fast you drive, the amount of traffic, how long the sessions are......
From my experience on a relatively open track you will be OK at 100 if you are NA as long as you stay at about 20-30 minutes for session length
+1 it really depends on the circuit, humidity, track temp. There's a local one not far from me where mine gets to 230 after 20-25 minutes on a 90f day, nothing I can do about it. Another track not an hour away I can drive all day in 90f and not hit 220. The first one is all gas-brake-gas-brake, about 60mph average speed. The second one is long sweeping turns about 80mph average speed. Better invest in cooling and monitor the temperature with a separate gauge or via an OBD device. The stock gauge doesn't move until it's too late.
The recommended mods for this kind of duty are:
Re-medy water pump
a 2009+ radiator or an aftermarket dual pass radiator, such as BHR
sealing around the radiator with foam
the engine undertray MUST be in place, it's a functional part for forcing air through the rad
Thanks for the info. I don't know much about rotaries, but I've heard heat is a big issue with them, and I want to make sure I'm not abusing the car. Fortunately summer is over, so it's unlikely temps will be very high the next time I do a track day, it'll be a good chance to get a baseline of my temps.
In my Miata, a gauge I found very useful on track was an inexpensive oil temp gauge. I paid under $50 for it. Simple to hook up too, from the same place I got the gauge, I got an oil drain plug with a threaded hole in the middle to screw in the sensor, then ran one wire. On the street, oil temps never went above 220, even on the interstate in 90* weather, but on track temps hit 260. That 40 degree difference was a good illustration of how much harder on an engine track driving is than street driving.
I would be leery of tracking an '05 with the stock cooling system. The plastic tanks on the radiator, the coolant bottle nipple, and the coolant bottle itself are known to fail under stress in a car that old. Cooling is the single most important thing on a tracked car (followed closely by lubrication). The cost to refresh (or upgrade) the cooling system is almost nothing compared to the cost of replacing the engine.
I would be leery of tracking an '05 with the stock cooling system. The plastic tanks on the radiator, the coolant bottle nipple, and the coolant bottle itself are known to fail under stress in a car that old. Cooling is the single most important thing on a tracked car (followed closely by lubrication). The cost to refresh (or upgrade) the cooling system is almost nothing compared to the cost of replacing the engine.
Did the S2 coolant bottle, cap, and other failed bits get improved on the S2?
I have an R3 parts car at my house and the reservoirs looks identical to the S1 reservoir. the S2 does have a larger radiator and more powerful fans though. And a better water pump.
If you hold at for a long time above 7K, the stock pump will cavitate. It will quit flowing water in any useful quantity. Temps will go up fast. The fix is a Remedy pump (Loki) or an underdrive pulley. I have a Remedy pump.
Search, there are some good lists of things to take to the track. Many are directed towards your safety and well being.
For sake of comparison, I don't let my coolant temps go over 220F on the track. With the cooling system upgrades inherent in S2 cars plus my Koyo radiator, I don't have to worry about that happening anymore--even in 100F heat.
Here is a thread that details my radiator install and has nifty charts and graphs of my before and after temps:
If I had a 2005 and wanted to track it, I would immediately do the following without hesitation:
- Upgrade to all aluminum radiator with proper foam sealing and undertray
- Upgrade water pump to improved OEM or Remedy
- Replace coolant bottle
- Change thermostat just because it is 11+ years old
- Replace hoses while in there
- Flush coolant and replace with 60% water and 40% FL-22 (depending on your climate)
- Test fans for function and speed and replace or upgrade if needed
- Add a fan switch to the dash to manually cycle fans
- Use OBDII reader or gauge to monitor actual coolant temps
I would also plan to perform these reliability mods / best practices:
- Use an AccessPort or similar to increase lubrication rates and lower fan turn-on temps
- Add at least 2oz of JASO FD 2 cycle oil to each 1/4 tank of gas
- Upgrade ignition to BHR or similar
- Replace OEM catted midpipe with BHR or similar with or without a HJS motorsports cat
.
Last edited by Steve Dallas; 10-17-2016 at 10:10 PM.
If you hold at for a long time above 7K, the stock pump will cavitate. It will quit flowing water in any useful quantity. Temps will go up fast. The fix is a Remedy pump (Loki) or an underdrive pulley. I have a Remedy pump.
That is not entirely true. Cavitation reduces pumping efficiency, but water will continue to flow in plenty-useful quantities. If that was true, we wouldn't be getting tons of cheap **** from China because no boat would be able to move (they all have some cavitation). Look at my signature. I'm using a stock pump. I don't overheat.
That is not entirely true. Cavitation reduces pumping efficiency, but water will continue to flow in plenty-useful quantities. If that was true, we wouldn't be getting tons of cheap **** from China because no boat would be able to move (they all have some cavitation). Look at my signature. I'm using a stock pump. I don't overheat.
What temps do you run at what track? For me on an otherwise stock cooling system the Remedy made the difference between 225F and 215F peaks at one track and 230F to 225F at another under comparable conditions. None of thise are strictly speaking overheat, but you want some margin. Cooling parts are cheaper than engines.
With stock radiator the highest I've seen was high 220's, never 230+. That was when I was really cranking it on a hot day. I'm using a Ron Davis single-pass radiator this Summer, high temps still right around 220. I have 75,000 miles on the stock pump.
My stock system, on a 100F day, would reach mid 220s if I wasn't careful. Here is a chart of how it behaves with the Koyo radiator, revised coolant concentration, and foam/undertray strategy I have implemented on a similar 100F day:
That is not entirely true. Cavitation reduces pumping efficiency, but water will continue to flow in plenty-useful quantities. If that was true, we wouldn't be getting tons of cheap **** from China because no boat would be able to move (they all have some cavitation). Look at my signature. I'm using a stock pump. I don't overheat.
Cavitation on boat propellers is a different issue. Automotive water pumps use impellers.
I've actually done the stuff to show why you won't necessarily overheat with a stock or the aftermarket impeller (it's on this forum actually, you can see it) , but they both have extreme disadvantages in different areas.
I'll add that the S2 impeller is superior to both, but isn't compatible with the S1 front cover.
Legot, I've seen your work and it is very good. But 04Green's statement that water will "quit flowing" when the pump cavitates is wrong, and your work shows that it's wrong. I didn't want to leave that bad information hanging out there unrefuted.
It's a shame the S2 pump doesn't work on the S1's, but with enough properly-installed radiator the S1 pump works just fine.
P.S. There are some fast cargo ships that use KaMeWa water jets. So, Impellers on ships!
One thing I did on my R3 to increase cooling on track to good effect was to open up the stock grille using a dremel to cut away the blocked areas of the grille so that it's all open except around the perimeter where it's blocked by other stuff from behind anyway. Also cutting out the wheel well behind the oil coolers and installing wire mesh in place helps, as does sealing around the oil coolers.
That, plus radiator sealing made the difference between having to back off to let it cool down and being able to go hard all session long. Keep in mind though that this is not in the heat of the summer.
Sure, does not stop flowing completely. In my situation, it foamed the coolant and stopped flowing enough to keep engine cool and spike temps. Remedy solved it. Also, aerated coolant sucks at transferring heat.
And, my boat would stop when it blew out and sucked air (used the term ventilate instead of cavitate because it would suck in surface air) . We were going nowhere for a few seconds until the foam went away (200 merc, 27" prop, 18 foot boat).
But, you are right, coolant like bubbly substance continued to flow, it would even get to the bottle and let the float sink (back when my float worked). That is how I traced it. Only did it above 7,500, and only if you held it there a few seconds (track only).
And I like the S2 impeller. A blend of the two. They are actually related.
And I really liked the work that Legot did. I was able to match my issue to pretty close to the RPM he predicted. That drove me to the Remedy, and I have not seen the issue again. And, I have the stock radiator (for now).
I run at Thunderhill a few times a year, which is pretty much the "hottest" track in NorCal - Laguna Seca tends to be a lot cooler, and IIRC ambient temps around Sonoma tend to be a little cooler also.
I run a 2006 with a Koyo rad, new thermostat and upgraded hoses, plus fresh foam around the radiator. I don't think I've coolant temps on the OBD-II reader ever go over 210 even in 100F+ ambient temps. That's with 20 minute sessions, I'm pretty sure I don't want to run it much longer though without water pump upgrades or underdrive pulleys.
Thunderhill is pretty brutal in the summer. Air temps are high and you are on throttle for a good % of the lap. Buttonwillow is similar, but with even higher temperatures. I would assume you need better cooling for both of these tracks.
Laguna Seca also uses a lot of throttle, but air temps tend to be lower, so brakes take more of a beating than engine temps. However, when the sun comes out, and it reaches 80+, I don't think it will take too long to find the limits of the stock system.
Sonoma is pretty easy on engine and brakes in comparison.
On upgrades, lowest cost (and minimum imo) would be an aftermarket s2 radiator, new thermostat and new s2 water pump (or remedy pump, although your pulley might help with the s1 pump).
After that, you're looking at a koyo s2 racing rad, and then a dual pass rad. Possibly combining those with hood vents.
Having reached the limits of the koyo racing radiator, I'll be installing an rx8performance dual pass radiator soon...
Nice driving in that video. I might take my RX to Laguna Seca this November, for a Golden Gate Lotus Club event. I highly recommend them. Tons of track time, often 40 minutes out of each hour, small groups, and a relaxed and mature group of people.
Nice driving in that video. I might take my RX to Laguna Seca this November, for a Golden Gate Lotus Club event. I highly recommend them. Tons of track time, often 40 minutes out of each hour, small groups, and a relaxed and mature group of people.
Cool, I'm actually considering at doing that one as well...
Any reason not to throw in a remedy thermostat on an s2 with an otherwise stock cooling system? How long do the stock water pumps typically last? My car is an '09 with just 30k on the odometer. Just picked it up and am going through all the maintenance before the beatings begin. I'll be doing the fan relay kit, but haven't decided about the oil cooler thermostats yet.
09-22-2016, 09:08 PM
