04Green

iTrader: (1)

General Question of a thermal nature.

I worry about the car getting hot. But, what is considered hot?
I am looking for where I need to start worrying. I know the factory fans do not kick on until 205 F, so that is not hot. It is annoying, but not hot.

I know the factory temp gauge doesn't start to move until too late, but I think that is at 245 F or so.

If I am beating it around a Drivers Ed, and I get to 215 or 220, is that bad? Is it time to come in? Or, is it just time to pay more attention to my Ultra Gauge? The car does not seem to lose any power or be upset in any way.

I have a 2004 MT, with about 90,000 miles on this engine, a MM tune and a resonated mid-pipe. I short shift at about 8,500 at the track (unless there is a vette around). I opened up the vents behind the oil coolers, and the oil smells fine and does not show signs of thermal anything.

Thanks,

Mike

RIWWP

iTrader: (2)

Many of the engine rebuilders believe that the coolant seals can burst at 220F.

That doesn't mean that they will, but that is where you start rolling the dice. The hotter you get past that, the worse your odds are of escaping damage. If it was me with my 8 on track, I'd take every step I could to ensure that my temps remained under 200F, ideally under 190F. 207F fan trigger temp is only 13F away from danger, and that isn't enough of a buffer to me. (Wait, you have a MM tune and still a >200F trigger temp for the fans? You can drop that...)


As some somewhat correlated information, though not directly exchangeable, this is the cooling strategy that I've implemented for my MSM to remain cool on the track, stop and go traffic, etc...
- Highest efficiency radiator available (though 2nd highest capacity, the highest capacity won't fit with my turbo plumbing)
- SPAL fans that pull > 3 times the amount of air as the OEM fans
- radiator shrouding to ensure no leakage of air pressure around the radiator, must go through
- Hood venting in low-pressure zone behind the radiator to drop underhood pressures post-radiator, which increases the pressure differential pre-post radiator, improving efficiency
- 180F thermostat
- Fan trigger logic that triggers the fans at 180F if I am under 20mph, otherwise a staged trigger setup to turn one fan on at 190, the other at 195
- Warning light at 205F
- Lower rev limit above 210F, since although this isn't dangerous temps, if my temps get there, something has broken. The rev limit is high enough to use effectively, but low enough to significantly cut heat introduction into the system (just after peak boost it hit) and be obvious on the track

My last track event my temps were still under 195F after 20 minutes on track.

IRPerformance

iTrader: (6)

These cars can hit 220F in stock form. Mazda made them run excessively hot in attempts to reduce emissions (cars run cleaner when hot). I recommend lowering the temperature that the fans come on either through a tune or aftermarket fan controller. I like the coolant temps to stay under 200F. Aside from being easier on the motor, all the plastic and rubber components in the engine bay will last longer.

04Green

iTrader: (1)

thanks RIW and IRP

My fans trigger lower from the MM tune. I just used the mazda trigger as a reference point.

I feel comfortable with the 220 number above as a hard limit. It fits with some other data, and how close the coolant is to boiling at a hot spot. If that happens, all hell breaks lose since the local boil creates pressure that blows out the radiator cap, lowering coolant pressure that makes it easier for more to boil. It also dumps coolant out under the car where it is guaranteed to find the rear tires in a turn... That ends badly...

For my situation, fans will not help. they are not going to be 120 mph fans... Although, a standard fan may start to block airflow if they cannot keep up. Gotta think about that one.

I will look at the back pressure issue. I still have the battery up front as well as the tray under the stock air box. I would rather not cut the hood. So that is out. But a chin spoiler, right below the radiator, would lower pressure behind it. That has been a to-do item for 2 years.

Right now Ultragauge triggers alarm at 210 and flashes. I run fans on low at track, then they pick up at MM points. I think they are on high by 200 or so. But, 100+ is more than the fans will ever pull.

I have the opening around the radiator sealed per the $100 thread. I checked it last time I had the bumper off.

I think a path forward is the spoiler, check the thermostat, it may be too restrictive when partially opened. The temps do surge up and down 10 degrees during a lap. Around town, it pretty much stays pegged at 185 degrees. Pulling trailer down highway in 90 degree heat with AC on, is maybe 186. But, if the thermostat starts to oscillate, that might cause an issue. Those things to not respond quickly. I notice the problem at the same points on each track. Roebling and Sebring. And it is about 25 seconds after a slow stretch that could generate a partial thermostat closing, that then spikes when I step on it. I think a 180 would stay all the way open the whole time. But, if I have a factory thermostat, isn't that a 180 degree thermostat? I put a 160 in for a bit, but temps oscillated a great deal.

Again, thanks. and, anyone else, ideas are welcome.

Mike

IRPerformance

iTrader: (6)

So you are seeing these temps on the track at speed?

RIWWP

iTrader: (2)

Factory is 185F I believe, which is supported by your comment of "Around town, it pretty much stays pegged at 185 degrees". I preferred Mazmart's 172F thermostat on my 8. 160F is too low, since you will be dipping below the closed loop trigger temp, needlessly hurting street mileage and will likely causing one of:
P0125 - Insufficient coolant temperature for closed loop fuel control
P0126 - Insufficient coolant temperature for stable operation

I'm not sure about the thermostat cycling open and closed though. I understand your description, though I don't know that it is strictly a bad thing as long as the oscillation peaks stay under your goal temp.

Agreed on the hood. You have to rip quite a bit out of the 8's engine bay to get a clear path between the radiator and the hood.

04Green

iTrader: (1)

@ both..

Issue is noticed around 100 mph or higher. So definitely on track. And yeah, I did not like the 160 one. Too much variance.

I found a Mishimoto racing t-stat. Opens at 169F. Supposed to respond faster. It is tempting. And, is above the oscillation point I saw with the 160, so should be nice and stable.

The high points (or when I lifted due to temp) was about start finish at Roebling, and around turn 14 (bishops) at Sebring. Both on a 90 degree day.

I did not get the errors above with the 160. And, my ultra gauge showed closed loop while it was a 160. I go closed loop around 140 or so in the morning. But, I did not like the wide temp swings.

Looks like short term goal is t-stat (full open and stay the freak open) and reduce back pressure on radiator (chin spoiler, look for obstructions.

Thanks again.

IRPerformance

iTrader: (6)

Do you have an undertray on the car? Water pump belt slipping?

9krpmrx8

iTrader: (46)

The factory thermostat opens at 176F-183F and is not fully open until 203F. The fans should kick on at 207F and if not a DTC should trip at 208F. According to Mazda the operating range is 185F-243F. According to my builder (take it for what it's worth) Rob @ Pineapple says that on race cars running stock engines they typically saw coolant seal failure at sustained temps of 220F or above. But of course they sell heavy duty coolant seals so take it for what it's worth but my engine is boosted and compression is solid after 20,000 miles.

9krpmrx8

iTrader: (46)

I have a bunch of cooling mods and I am turboed so you can't really compare but the most noticeable was the addition of the FAL dual fan kit (420) and you can get a higher rated (440 I think) as well but both have a CFM rating much higher than the stock fans and Jegs makes a comparable setup that is cheaper and would work as well. We have three guys running these fans all in very hot environments and all but one are turbocharged and all report that the fans drops temps at a much higher rate than stock. I see great temps as well (never above 220F no matter how hard I push it) but I have a lot going on so I can't just attribute to the fans alone.

04Green

iTrader: (1)

All,

thanks for the data. IRP, I will check the belt. That is a good idea.

Consensus seems to be that I can use 215 as an alarm point. That I need to look at back pressure, that I might want to change the freaking 10 year old thermostat, and have one that is fully engaged below 203.

If the turbo guys are living with the stock radiator, and I am doing 100+ with temps rising, then I am thinking waterpump and/or thermostat. Both are original. Car has 127,000 miles on it.

The fact that it cools down quickly, several degrees, when I lift, also says I have some cool water in the radiator, it is just not getting to the engine fast enough.

thanks everyone.

Looking like air dam, t-stat, water pump, and I should be good.

Mike

TeamRX8

iTrader: (25)

From the latest Pro Mazda Renesis bulletin:


fwiw, the Mazmart t-stat is 169*F (76*C)


.

04Green

iTrader: (1)

Thanks Team

Question: What does Map Compensation Mean?

Rich Tune to cool things?

IRPerformance

iTrader: (6)

The main reason to get rid of the stock radiator is because the end tanks and nipples are plastic, and air prone to cracking. Changing the radiator itself won't do anything usually unless you also change the thermostat and fan trigger point. Map compensation can mean several things. Most ecus have correction factors for air temp, coolant temp, voltage, etc. The never cars have trims for air/fuel and other stuff as well. Usually that refers to how much the ecu has to adjust from the map to achieved the targeted parameter.

WaitingforFI

iTrader: (1)

9K,
With regards to your black fender vents, are they functional or just decorative?

9krpmrx8

iTrader: (46)

Well they are open, they are as functional as the stock ones, which are according to Mazda are functional.

TeamRX8

iTrader: (25)

Yes, but they run a MoTeC racing pcm system. The factory software uses a similar strategy, but that particular note may differ from OE. The MoTeC software is encrypted to keep competitors from accessing and modifying it to maintain a level playing field.