olddragger

iTrader: (3)

I was thinking about coolant flow and decided to do this. I have never trusted the by pass to completely seal in this system either.
Barrel type thermostats allow a higher flow rate of coolant pass it. It also has 3 pre drilled holes to allow for by pass flow during warm ups. It is rated at 180F.
The pics show how I also smoothed out a lot of ridges in the housing to also help with less restriction in the coolant flow.
I think it is a better system than oem--especially if you decide to run Evan's coolant.
You do have to do some clearance work on the inside of the housing to allow for that barrel to fully open.
ODhttps://www.rx8club.com/attachment.php?attachmentid=177089&stc=1&d=1316363 205
https://www.rx8club.com/attachment.p...1&d=1316363416

paimon.soror

iTrader: (15)

not seeing any pics silly pants

nycgps

iTrader: (1)

are you having heat issues od? I mean if race team is ok with stock system ...

olddragger

iTrader: (3)

i am working on the pics!
Sorry for the pic quality--yall know my reputation with technology.
But you can see how much open this is.
The barrel ( the brass bottom tub) on the aftermarket thermostat drops about 1/2 to 3/4 inch when it is open
All the ridges/sharp edges are now gone. That should help with flow a little.
I sealed the bypass hole with a 3/4 inch threaded stud that I screwed in and added JB wield. I shouldnt have to worry about it coming out!

TeamRX8

iTrader: (25)

you are assuming there is enough flow velocity to create a restriction

your engine warmup must take a long time, this will incur more wear and oil dilution over time

ditch the t-stat holes and instead weld on fittings with a bypass loop directly into the WP inlet using a normally-closed electric solenoid valve, then you will have something useful

olddragger

iTrader: (3)

true -there may not be. I wish I had the equipment to properly flow test stuff, but I dont.
I do have some observed information that may suggest we are not getting enough coolant flow in the lower rpms--more on that as it reveals itself.
I also figured that IF I decide to go with a thicker coolant--then it couldn't hurt?
Actually warm up is not extended but maybe one to two minutes more during 45mph suburban driving. Thats without the secondary radiator. i am currently running without it. Ambients have gone down a great deal here.
i do have to admit I have never liked the by pass system we have--your idea would be much better.

ASH8

Denny, I tend to agree with you about the RX-8's water pump for Both Series 8's and low RPM Coolant flow...There is probably an engineering reason why Mazda have gone smaller and smaller with their impellers, earlier RX-'s had larger ones and slightly larger pulleys..larger pumps...I believe the 8's it is somewhat inadequate below 3000 RPM on hot days..

Thermostat is interesting...personally no experience with the "barrel type" shown.

Thanks for posting, you are always one to share info and experiment with solid idea's.

On-ya OD!

longpath

iTrader: (1)

The few days I've seen 98F weather with stop and go after having been on the highway for an hour or more, I did have high temps (including a Scangauge II reported 245F in July of last year). Everything was fine until I was required to run the AC full blast in stop and go traffic. I had no issues at cruising speed. My own thinking had been to find a way to use one of the RX-7 thermostats but I've not found adequate pictures and other data for a comparison. I am planning a switch to the REmedy coolant pump.

olddragger

iTrader: (3)

Thanks Ash! I do try. I do make mistakes too.

I did this mod for several reasons.
1- barrel type thermostats do flow more than oem style--that is undisputed.
2- I personally do not like this by pass system in my climate ( mostly hot)
3- I have observed some low rpm cooling questions that are not air flow related
4- I do not drive my car as much now so I have about 75% decided to convert to Evans coolant --which is slightly thicker.
5- why spend money and do a lot of work on the cooling system without addressing one of the key components? Ok that doesnt make sense--but the others do?
Now I have just installed this--so I dont have any running data to share. But so far--so good.
There is a particular environment I want to repeat to see if this mod has any effect.
By next week hopefully.
Cost of this mod is about $14.

Longpath---245F --are you kidding? Are you running Evans?

PhillipM

I didn't bother with the thermostat but I did do some reworking on the housing itself, the casting lines from either side leave a lot to be desired, even at low flow they're pretty dire.

I didn't touch the port itself as you have as that was fine on ours, but did go with a larger radius from the port to the chamber.
Car did seem to keep slightly cooler under high rpm/high load afterwards, but I can't be sure as the datalogs also showed a slightly cooler ambient at every event since.
I have the opposite problem though and have to use an underdriven SII impellor as otherwise there's a lot of cavitation higher in the rev range.

olddragger

iTrader: (3)

thanks for posting.
I touched the port because to install this type of stat you have to sand back a little ridge inside the housing to insure that barrel can have free rom. Since I was already there--i said "why not"
I know what you are saying about those casing marks--they are pretty rough.
Every little bit helps.

TeamRX8

iTrader: (25)

it only helps if it helps, extra work is no guarantee of anything being improved outside your own mental imagination

longpath

iTrader: (1)

Not kidding or exaggerating. Yes, I'm using Evans NPG+. I don't think I'd still be on the original engine if I hadn't made the switch to Evans NPG+.

olddragger

iTrader: (3)

ok thats tolerable with Evans?-wow.. I am almost ready to convert myself. I figured too that the better flow through this part of the system couldnt hurt since Evans is a thicker fluid.

Team--imagination is a birthplace for ideas.
I know where you are coming from though. Nothing like evidence based modifications, but pray tell, how would you analaze the need to close this bypass system and to increase the coolant flow rate through the thermostat? Coolant can never flow too fast.
I guess you could add thermocouples to different sites on the engine and measure the difference in the rate of metal temperature rise, the max temp seen , metal range of temps etc with the oem system. Then repeat this with the modification----all under a controlled enviroment. I guess that would be the best way to do it?
Or you could do like me and say " Hey, that looks all clogged up, lets unclog it and see what happens"!
I need to change my name from Olddragger to Backyard Idiot.

TeamRX8

iTrader: (25)

nobody is claiming that you're an idiot, you are simply putting too much emphasis on minutia.

zoom44

coolant can flow too fast

olddragger

iTrader: (3)

I was only joking around about that. Borderline, maybe, but I keep working on it .
You are right about little gained from the work, but idle hands..................

Zoom, the companies/race teams that i have had any dealing with all have told me the same thing. Coolant cannot flow too fast. Now there are extremes for anything . Just ask my banker for example.
But, in theory the faster the flow the better the heat exchange. However there is a law of diminishing returns. The way they explaned it made sense to me.

zoom44

why do we have a thermostat?

PhillipM

The difference is, we'll quite happily spend 15 minutes warming the coolant and oil through in a morning and then the car never cools down all day to the point where you want a thermostat, so it makes sense to remove it to boost high rpm cooling.

However, holes in the thermostat/no stat means longer warm up times and more engine wear because the oil/water isn't up to temperature as fast, probably not quite so good an idea for a road car.

olddragger

iTrader: (3)

thermostats are there to keep the engine from running too cool. Which the engine will do if the coolant system is capable.
It is much better to have system that relies on the thermostat to regulate the temperature than to have a system that is having to run with the thermostat fully open to adequately cool the engine.
Anything you can do to increase coolant flow rate ( within reason--less than 10 ft per sec) will improve heat transfer and cooling performance.
Anything you do to restrict or reduce the coolant flow rate will hurt cooling performance.
What flow rate does effect is the temperature of the coolant in any given region of the system. To low a flow will allow a larger temperature gradient to exist from inside the engine to the radiator. You want that coolant circulating as fast as possible so that it moves the heat from the engine to the radiator as fast as possible. This will result in the greatest possible temperature difference between the coolant and the engine, and between the coolant and the radiator surfaces..

Now my head hurts.
OD

zoom44

so you just agreed that coolant can flow too fast.

olddragger

iTrader: (3)

Lol---sure!

paimon.soror

iTrader: (15)

Lol all good points, but don't forget the laws of fluid dynamics and laminar flow, meaning that if your flow rate is actually too fast, you create a vacuum within the system, this meaning the least resistance now sits in the absolute center of the current section's passage diameter. Laminar flow now causes water to cling to the sides of the passage, while the center is flowing. So now you have a faster flow rate in the center of your passage, with a far slower rate of flow on the outer banks. This is not what you want in a device that you are trying to reduce localization of hot zones

ASH8

In layman's terms one would think "if" hot coolant/oil is flowing too fast then the ability of the Radiator/Cooler to extract or dissipate that heat from coolant/oil also diminishes, after all the radiator/cooler is relying on external air flow passing through radiator/cooler fins to cool them down, hence cooling down the liquid or coolant....same as Oil Coolers.

If coolant/oil is flowing too fast then a radiator/cooler is unable to reduce coolant/oil temp and in a very short time everything would become heat soaked?

Same would apply if flow is too slow..

I recall my mums 1993 Mazda 323 Auto with a stuck thermostat in closed position causing the engine cooling system to overheat and pressurize in the middle of a freezing winter during a 25 minute trip (luckily engine was OK and still going strong 40K later).

And yeah, a stuck open TS over-cools engine...

Easy_E1

iTrader: (2)

Heat always flows to regions of lower temperature, never to regions of higher temperature.