Would holes in fire wall at windshield cowl provide low pressure engine compartment flow?

 

They will force high pressure air from the base of the windshield, into the engine compartment, thereby reducing the needed pressure differential across the rad core. Basically the same effect as hood risers.

 

Roger that.

 

Hey guys,

First post. Love the activity of this forum versus others. Many people viewing all the time.

I am in the process of adding an oil cooler to my miata (race car) by ducting flow from the passenger front turn signal. I am curious what you have guys have to say. I am thinking this will pressurize the engine bay. Thus hurting cooling temps. I have not done the coolant reroute yet.

Am I okay to continue my oil cooler mounting? Any suggestions for a better place?

At the end of 30min races my water reaches 235 and 255+ for oil with ambient at 90+. Mishimoto rad.

 

You should be doing cool down laps around 220. Shutting down at anything above 230. My personal preference at least. If you're doing a race for money, ok. But if this is a HPDE? Not worth the potential engine melting.

I'm not sure the front signal is a great place for air flow, however if you're worried about air pressure, stick a vent in a lower pressure zone of the hood, aka right behind the radiator.

 

fwiw- A large (18") aluminum baking sheet makes a decent fan shroud for cheaps ($8). I never used a shround on the Miata (no AC), but my Benz takes advantage of it to pull more air through the condenser with the addition of a pull-a-part Volvo (Seimens) two speed "reportedly 3000cfm max" or <$40. I haven't seen the cfm officially spec'd but it pulls lots of air- similar to my Spal 3000cfm when in top speed. I walked out with two fans, all wiring/connectors and relays (two speed triggers) f. The benz install uses the coolant thermos witch for the first trigger/speed and the AC switch for the second. Both are +12v so extra relays (from a Miata) were used with the Volvo parts. Wired so that either can trigger speed 1 and if the another trigger is introduced fan will ramp up to speed 2. Certainly applicable to boosted Miatas with multiple exchangers. It's what I will run in my Miata with rad/IC/AC-condenser stack.

 

Ghetto plasma cutter compass>*


That's excellent.

 

Lol. Definitely the coolest thing I've seen today.

 

So is the SuperStat termo worth getting? Kind of confused after watching the video with the guy drinking beer.

 

Joe did not measure flow rate. We didn't either but field test results strongly support a steeper flow to temp curve and lower peak temps.

 

I am the "beer drinking guy."

As Emilio said, neither of us have measured flowrate, yet he expresses a preference for the SuperStat based on measured temperature and I express the opposite preference based on visual observation outside of an engine.

(It's not often that the two of us strongly disagree on technical matters, and it sets up a sort of "don't cross the streams" dilemma.)

Based on the fact that I observed the SuperStat to open later than the regular Stant unit, and to achieve a smaller overall opening, I know that, for the two specific units which I tested, an engine equipped with the RegularStat would see more coolant flow through the radiator and less bypass flow (through the heater core and back into the mixing manifold), than one equipped with the SuperStat.

The caveat, of course: Both of us are basing these opinions on a small sample size. Mine is a sample size of one, Emilio's is slightly larger. It may simply be that Stant's QC is poor, and that there is a large variance from one thermostat to the next which neither of us have adequately observed. Or it may be that they've made some change to the design of one or both (making the SuperStat better or the RegularStat worse) in the 6 years since I made that video.

At any rate, the difference is likely to be small, especially in comparison to the performance improvement to be gained by doing a rear-thermostat reroute. An engine running a rear-therm configuration with the poorest-quality thermostat available will be cooled better than one running a $500 gold-plated thermostat lovingly hand-crafted by German artisans, in the stock configuration.

 

Sample size of 2. I boiled a sample of each and reported the results before you made your famous video.

 

Very interesting cooling system information in this thread:

Pirate4x4.Com - The largest off roading and 4x4 website in the world.

 

Nice!!

Keep in mind, written for a 4x4 rock crawler. The information pertaining to fan shrouding, which is critical at low speeds, doesn't translate all that well to a Miata being driven on track. No fan can come close to generating the delta-P across the cooling coils that forward vehicle motion + proper ducting of the radiator can achieve.

Other than that . . . great info.

 

Exactly. Large farm tractors are "only" 500-600 horsepower, less than F1 cars. But, given that their average operating speeds are in the 1-4mph range, compared to 100+ for F1 cars, the fan and shrouding requirements for them is massive.

For cars on track at speed, the key requirements are that the incoming air be ducted such that it must pass through the heat exchangers rather than around them, and that the airflow then be given an exit from the engine bay. The stock undertray provides the second part. For greater heat rejection the hood can be vented. For advanced aero configurations (flat/partial flat underbody, front splitters, etc) care must be taken when venting the hood to ensure the trans and diff still receive enough airflow to be properly cooled.

 

I believe he is preparing a desert racer similar to Baja 1000 entries. But the technical info is very good.

 

Mods, can you turn this thread into a sticky so that it's easy to find?

There is a lot of very useful information about the Miata cooling system in it.

Thanks

 

^ Agreed. A lot of those trucks have the radiator mounted behind the cab where air flow is less than optimal. Without a shrouds those trucks would live a short life. It is a great read however when taken in context.

Makes me think about the vehicles that came from the factory with no surge tank and rad cap below the highest point (like my grand cherokee). It has a bleed plug for filling coolant. Now seems inherently flawed from the factory.

What are thoughts on "Evens waterless coolant"? Anyone run it? Expensive. Claims are pretty big.

Also no mention of cavitation. And the additive packages to combat it. Especially with diesel, but that is here nor there with this forum I suppose.

 

Don't ever question Pirate4x4.com...

I swear to god nearly 80% of my google searches always lead me to Pirate4x4 for the answer... It's the strangest thing.

 

And the other 20% to pirateBuTT?