lead69
hopeless car junkie
I have only checked high performance t-stats but the multiple ones I tested started opening lower than the advertised rating (10 degrees or so) and were basically full open by the time they reached temp.
Coolant flow
- Thread starter Rat Bastid
- Start date
-
Yup, that's my experience as well. I always chuckle on these threads where we are clearly discussing high performance applications and everyone wants to throw stock crap parts in the mix, just so they can be "right" while not realizing that makes them even more wrong.
dirty white boy
50 yr old Juvenal delinquent
how old is the info in these books yall posting? post pic of copyright dates in the front of them books!! yall ever think technology advances, or stands still threw out time??? theres cheap stock replacements stats, high priced stock replacements and then theres better than stock, think there all made the same??? not a fan of t-stats my self just something to malfunction and cost ya a head or hole engine! takes just a few minutes more to warm up but never any doubt my coolant flowing!!
Don’t be a literalist.Packing up, backing up, obstructing, impeding, blocking, restricting, whatever you wanna call it. I posted what I experienced with this Derale:
View attachment 1716086405It wasn’t cheap $$ that’s for sure. Flat plate shroud with high CFM fan. It didn’t take long for me to discover it had to go. You may have known this from the beginning of time, at the time I bought it I had to find an 18 inch fan with shroud that would fit my situation for dragracing and street use. For that it was fine, although I had to run it more than I care to. It was no good for Highway use in my application. And that style is what I am referring to which is the exact same thing you are referring to.
As to your assertion that I said a mechanical fan was “necessary“ maybe you have misread or perhaps you misinterpreted I don’t know, this is exactly what I stated:
Re-reading what I typed, it could be you are focusing on the part: “and/or” and perhaps I left out “or” between “blocking airflow, OR a good mechanical......” Was not implying having to use both, no sir. Perhaps I was not as specific and clear as I could have been. Grammatical errors happen.
Instead of seemingly looking to pounce and parse maybe try asking for clarity or simply give the benefit of doubt. No big deal. I know I need to sometimes so, anyway, have a nice evening
That may not be a cheap fan cost-wise, but as you found out it's completely inadequate. The fan shroud is just a cookie sheet, not a piece that was designed for air flow. And the fan itself is only rated for half of what you'd need to cool that engine, if that.
Buying an expensive aftermarket fan does not guarantee success. You need to make sure it can put out enough CFM for your application, and it has to be designed to work with its shroud to flow air. The Ford Contour electric fan set up I run costs significantly less than that DeRale, and flows twice as much air.
Your RPM example is exactly why mechanical fans are inefficient. The fan has to do the most work at idle, when a mechanical fan is turning the slowest. At higher engine rpm's the car is MOVING, which means your airflow is coming from the speed of the car, not the fan. You don't even need the fan to be spinning at all once you're doing 25mph or more. The electric fan always spinning the same speed is an advantage, it can flow the most air when the engine is at idle and the car is sitting still, which is exactly when you need the fan to be doing the most work.
And yes, I am very familiar with how much air a mechanical fan can move. Which is why I picked an electric fan that can move just as much. If you've ever seen a Contour fan set up running at high speed, you'd know it moves just as much, if not more, than the mechanical fans these cars came with. Especially if the engine is just idling.
I don't need to do any research on cooling a dirt car, there are electric fans more than capable of cooling those engines. But as you said, the class of racing you're talking about doesn't run alternators. An electric fan that would cool those engines needs to be supplied with 40+ amps of power to deliver their rated CFM. This just goes back to the basic mistakes people make when choosing electric fans- they don't pick a fan with enough CFM, they don't wire it with the heavy duty wiring and relays needed to supply the power they need, and they don't run a power source capable of feeding the right amount of power to the fans when they're running.
I have no issues cooling my 400+ hp, all iron 340 with the electric fans I run. They never even come on when my car is moving more than 25 mph, and they've cooled it just fine when it was 110° out and I was stuck in traffic. That's a harder ask than anything a dirt car with 400 hp requires.
Once again, you're looking at this whole thing through the VERY narrow window of maximum power output on a dyno or at the drag strip. All of your examples are drag racing or dyno's, and it's why you're so dead set on this (and wrong for other applications).
I know you're well versed enough in building engines to know that max power output is not the only way you can tune. It would be very different from a maximum efficiency tune, for example. And you throw out "drivability" too, and for street drivability there will be very few engine builds where tuning for maximum power will actually give you the best drivability. Tuning for mid range torque, for example, vs maximum hp, would give you a much more street drivable car. And that's not gonna push the limits of detonation. For that matter, a lot of engines in these cars are no where near pushing the limits of detonation.
As I said before, drag racing is quite possibly the ONLY automotive motorsport that runs coolant temperatures below 180° or colder. There are much more exotic engines that don't do that which go A LOT more miles than any drag car or even most of the "street" cars discussed on this board.
And you can't just say this is limited to 50 year old engines, because I've seen you give this advice to guys with modern engine swaps. You're giving out advice that's good for the niche it belongs to, but is not necessarily correct for everyone that you're giving that advice to. There ARE disadvantages to running too cold. Just because you personally haven't seen it doesn't mean it's not true. You're not basing your advice on engines that are meant to go 100k+ miles. And yeah, most people don't drive these cars like that. But your advice is not absolute. It's a single way, out of MANY ways, to tune an engine.
I'm not gonna argue with you on this. I'm sure what you do works for how you build engines and how you drive. But it's simply not scientific truth that the way you do things is in fact best for all engines and all applications. For a drag car or a street/strip car, sure. For anything else, sorry, but no. Your experience in this, while valuable, is anecdotal.
Rat Bastid
Dunamis Metron
But YOU are arguing. I drive my **** ON THE STREET. Just because YOU cant or won’t do something isn’t my problem.
Maybe you ought to drop your coolant temperature, retune your carb and ignition and then report back how shitty it runs. Or maybe how much better it runs. ON THE STREET.
Get the “racing” thing out of your head. That’s your mental road block.
I don’t think I’ve ever said for an EFI (junk you call “modern”) deal to drop the coolant temperature. If I have, it’s because of testing on STREET DRIVEN CARS close to two decades ago.
......yeah and every single one of these antiquated books had ZERO clue about how ethanol laced gas would affect these engines. Leaning them out, causing hot spots and so on. You have to compensate for "whatever" fuel you run in the tune, or it'll never run right. Some of these guys just want to be right, no matter how wrong they are.
I haven't seen anywhere once in any of these discussions where you've mentioned racing only. I don't know where that's coming from.
Your street car and my circle track car are polar opposites when it comes to cooling system requirements. But for the sake of this discussion let's say that what they have in common is that they both have motors that make 400 horsepower. That is the point I was making in the post. Different applications require different cooling systems including fans.
You said your street car needs to move the most air at idle. The only time my circle track car is idling is when it is in the pit warming up for the race. If it's cool out I have to put cardboard in front of the radiator to even get the needle to come off the peg on the temp gauge. There is no load on the engine at idle so there is very little heat that is produced by the engine and the fan on my racecar even at idle speed is overkill. Is that fan inefficient at idle? Absolutely. But that big (overkill at idle) fan is going to have it's hands full when the car is at speed on the racetrack. Because it is under a heavy load the entire time it's on the race track with no break. Except for an occasional caution flag.
You said your car doesn't even need a fan above 25 mph . The air flow through the grill is sufficient to cool the car. That's because your car's engine has very little load on it to propel itself down the highway. My circle track car has air going through the grill too. It also has an air dam below the radiator to pick up even more air. And that's not anywhere close to enough air to keep the motor cool with out the additional air provided by the fan at 6000+ rpm. It wouldn't make it two laps without a fan and the gauge will be pegged. Due to the continuous high load on the engine.
I'm not saying one fan is better than the other, electric or mechanical. Each has their advantages. I'm saying different applications may require different types of fans.
Put a hitch on your car and hook a 10,000 pound trailer to it. There is a chance your.cooling system requirements might change. Different application, different cooling system requirements.
Last edited:
Getting back to stats: some of the books quoted might be 'antiquated'....but it doesn't matter because the way the stat operates has not changed since Adam was a boy.....
I have measured a lot of the 'hi flow' stats: Robert Shaw, Milodon, Mr. Gasket etc. probably all made in the same Chinese factory...
Reason I did some tests was that my engine ran very cool, too cool for my liking, was using the 160 stat. I used a digital temp probe for testing. What I found was that the stat opened at 160 [ all good so far...] & was fully open 20+* later. If the temp THEN dropped, it dropped to about 140* before the stat was fully closed again. The temp regulating mechanism inside the stat was either faulty &/or just not very accurate.
I now use the Stant SuperStat, which I also tested. Opens bang on the rating....& also closes bang on the rating.
I also have a Robert Shaw 140* stat. I presume it is for a marine engine or aircraft engine.
I have measured a lot of the 'hi flow' stats: Robert Shaw, Milodon, Mr. Gasket etc. probably all made in the same Chinese factory...
Reason I did some tests was that my engine ran very cool, too cool for my liking, was using the 160 stat. I used a digital temp probe for testing. What I found was that the stat opened at 160 [ all good so far...] & was fully open 20+* later. If the temp THEN dropped, it dropped to about 140* before the stat was fully closed again. The temp regulating mechanism inside the stat was either faulty &/or just not very accurate.
I now use the Stant SuperStat, which I also tested. Opens bang on the rating....& also closes bang on the rating.
I also have a Robert Shaw 140* stat. I presume it is for a marine engine or aircraft engine.
Blah blah blah....I hear something flushing backwards.
That book I showed is from 1970. The Mopar Performance book (when was the thermostat tech written, not sure) shows this:
All these articles, books show is how the acceptable range below/above a thermostats rating can be. There’s Wide variation. I think it’s safe to say they are all referring to Standard production style thermostats allowing for Production tolerances at the time.
The closer to the thermostats rated temp they start to and are fully open the better.
I think it’s a good thing to read articles regardless of when they were written, not to win (yeah, maybe for some) as it shows how it was, any progress up to where things are now. And it might provide context
and for the record, the make up of the fuel had little to do with the heat produced. For practical purposes the energy produced to overcome a load, be it friction at idle, or towing a trailer is pretty much the same whether its 1970 fuel or the latest RFG.
The difference in compositions mostly effects reid vapor pressure, and distilation curves. For practical purposes this means how easy it is to initiate a flame kernal, how long it takes to grow, and how well it burns up the heavy end.
The difference in compositions mostly effects reid vapor pressure, and distilation curves. For practical purposes this means how easy it is to initiate a flame kernal, how long it takes to grow, and how well it burns up the heavy end.
Here’s a good post from a few months ago. I like what the poster says about his temp gauge readings:
[ATTACH=full]1716087589[/ATTACH]
[ATTACH=full]1716087589[/ATTACH]
NoCar340
The Original Partstitute
One more thing I rarely see mentioned: The thermostat itself. This is a factory air-cleaner decal from a '70s CB300:
It was made by Robertshaw for Chrysler. The design of the stat was so important ("WILL" rather than "MAY" CAUSE OVERHEATING) they included a drawing of what it should look like. It's no longer available new anywhere; NOS is the only option. Sounds terrible, but several other vendors sold the Robertshaw unit under their own names and part numbers (Purolator, Atlas, even CarQeest at one point) so they're still out there. Cross-references are only good if the stat looks like the diagram above.
Does it make a difference? With dramatically increased flow, it certainly should. My '69 Valiant has a 10.x:1 340 w/painted headers, a shroudless thermal 5-blade clutch fan and a cheap 22" Chinesium/aluminum radiator. The VDO mechanical gauge stays at 180° like the needle's welded in place with ambient temps above well over 90°. The factory dash gauge is similarly steady (both gauges work simultaneously) and I've verified with an IR heat gun. I can't swear it's the 'stat, but when the ambient air is 98°, the car's motionless and running, and the needle stays planted like that, I'm not trying something else.
Attachments
Last edited:
That is the same style thermostat Stewart Components makes.
Just do what works for you. If you want to run your junk at 220 degrees idling in bumper to bumper traffic, at 99 degrees and 75% humidity, go for it. My junk runs good.
I could be wrong but I think Robert Shaw makes the thermostat for Stewart Components. Stewart Components modifies the thermostat for racing by drilling bypass holes in it.
MopaR&D
Nerd Member
Looks awfully close to the Milodon high-flow t-stat, I have one in both my D200 and Duster along with ECP aluminum radiators and high-flow water pumps. Neither ever have cooling issues. I've towed my Duster on a U-Haul trailer with that truck to a track and back over I-25 when I was in CO, just for kicks I held the pedal to the floor going 75 mph up a 6% grade for at least 30 seconds and the water temp gauge never went over about 210 (thermostat is rated at 195).
Since moving to the Southeast I should probably swap out the 195 'stat in the Duster for a 180 I already have. I don't really have to worry about driving in 20-degree ambient temps anymore and needing a heater lol.
Go with the 160. I mean seriously. Get the hot water in your sink up to 160....IF it'll go that high and see how long you can stick your hand under it. lol
In depth description here:
The original Robertshaw 330 series hi flow thermostats
And here:
Robertshaw 370 Series hi flow thermostat
Robertshaw 370-160 Series hi flow thermostat
The original Robertshaw 330 series hi flow thermostats
And here:
Robertshaw 370 Series hi flow thermostat
Robertshaw 370-160 Series hi flow thermostat
Last edited:
Man I don't want to jump in here but...
Keep in mind the only time the thermostat flows "high flow" is when it is fully open. Before that it is regulating the flow needed to maintain the low temp, on a cold day it might be bairly open.
I'm going to regret this
Keep in mind the only time the thermostat flows "high flow" is when it is fully open. Before that it is regulating the flow needed to maintain the low temp, on a cold day it might be bairly open.
I'm going to regret this
MopaR&D
Nerd Member
Man I don't want to jump in here but...
Keep in mind the only time the thermostat flows "high flow" is when it is fully open. Before that it is regulating the flow needed to maintain the low temp, on a cold day it might be bairly open.
I'm going to regret this
Well I for one already knew that, lol. I just wanted the extra "ceiling" for when my truck is pulling heavy loads or my Duster is running around a road course. In normal street driving (except for maybe bumper-to-bumper traffic which is rare where I live) all the "high flow" stuff does nothing.
-
