Heat soaked

[22Kart22]

Hey everyone. For those who have s197s, you know they get heat soaked as hell in this florida weather. To counter-act that, I am running a few oz of coolant, a bottle of red line water wetter, and the rest all distilled with the rear hood gasket off so heat vents better.


Anyways, would I see an improvement getting a 160 degree thermostat such as

http://www.brenspeed.com/hyp1011.html

or should I make my high-speed fan turn on a lot lower through my tuner?

[RyanWJ]

Ryan, assuming the ECU doesn't throw a fit because of the 160 thermo, I would go that route. You can only go so far with tweaking the fan settings before you prematurely wear it out.

I run a Jet 180, see if they make a 160 for the 3v 4.6, as they warm up just like the stocker does.

[22Kart22]

Wear out? You mean the fan? I believe they are brushless motors so the only parts that can wear are the bearings...

[RyanWJ]

Originally Posted by 22Kart22

Wear out? You mean the fan? I believe they are brushless motors so the only parts that can wear are the bearings...

Yes, the fan. Regardless of how much use/abuse the fan can take, running the fan is a bandaid for what you are trying to accomplish. the less work the fan has to do to keep things cool, the better.

[HORSEpower]

The 160 degree thermostat won't do anything. By the time the car is overheating, the thermostat is wide open already, and flowing as much as it can. What kind of temperatures are you getting? You're much better turning the fans on at a lower temperature. In order to get more radiator flow, you have to upgrade to a high-flow thermostat, not a lower temperature. Mr. Gasket makes them, and they are about $10 at Advance, but you have to go in there with a part number and order it, takes about a day to get it. This made a world of difference on my car. I have to warn you though, once you put a higher flow thermostat in, you won't have any appreciable heat in the car, because all the water is directed to the radiator, and nothing gets to the heater core. You can fix that by installing a heater core pump in your system.

Kurt

[22Kart22]

Well, its not so much that its over heating, it just gets everything really hot at a standstill. My only defense at a drag strip is running my heat with the engine off to get the coolant temp down. It to the point where I can feel the power difference after its been sitting at a light.

[TheSean]

Maybe get a bigger/better radiator? You shouldn't have to jump through a bunch of hoops to run safely, that's a shitty safety factor. But Kurt's idea is good. It's Florida, you don't need heat that bad, keep the engine safe.

[N-Dawg]

Originally Posted by 22Kart22

Well, its not so much that its over heating, it just gets everything really hot at a standstill. My only defense at a drag strip is running my heat with the engine off to get the coolant temp down. It to the point where I can feel the power difference after its been sitting at a light.

This would actually be pretty neat to get some empirical evidence on. If you want to be really cool (that was a terrible joke) you could pressurize the system through an aluminum header tank, albeit other modifications would be necessary.

[TheSean]

Originally Posted by N-Dawg

This would actually be pretty neat to get some empirical evidence on. If you want to be really cool (that was a terrible joke) you could pressurize the system through an aluminum header tank, albeit other modifications would be necessary.

I don't think you'd want to pressurize it enough to make a difference. Unless, of course, you want threaded or compression fittings on the whole entire cooling system AND have a new radiator that can handle more pressure, which brings us back to the point of simply getting a better radiator! Would be fun, though. Think of 100PSI of boiling toxic fluid coming out at your face when you try to fill the tank up! Then again I'm not really sure how much difference those 'high pressure' tank caps have on peak temp anyway. You could just let some vaporize and boom, there's your extra pressure! no need for a header. just make a marginal-at-best cooling system that can handle a lot of pressure!

I think more surface area and airflow would really be the best solution. KISS.

[Pifer740]

I'm heat soaked, baby.

[N-Dawg]

Originally Posted by TheSean

I don't think you'd want to pressurize it enough to make a difference. Unless, of course, you want threaded or compression fittings on the whole entire cooling system AND have a new radiator that can handle more pressure, which brings us back to the point of simply getting a better radiator! Would be fun, though.

Think of 100PSI of boiling toxic fluid coming out at your face when you try to fill the tank up! Then again I'm not really sure how much difference those 'high pressure' tank caps have on peak temp anyway.

You could just let some vaporize and boom, there's your extra pressure! no need for a header. just make a marginal-at-best cooling system that can handle a lot of pressure!

I think more surface area and airflow would really be the best solution. KISS.

Just grab some SAMCO hoses and you would be fine.




Letting some coolant vaporize works against you.

[N-Dawg]

Dead thread? No Sean? Sacrebleu!

[Luke01GT]

so did you ever find a solution to your problem?

[TheSean]

well i don't use plain water as coolant so I think that plot is garbage

and if that wasn't enough WTF is the X axis? Temp? In celcius or... rankine? someone obviously is abusing ther power of Excel 2007!!!

[RyanWJ]

I wonder if Ryan was actually talking about a problem with coolant temp, or heat soak in general. Heat soak doesn't really seem to be affected as much by coolant temp as much as it does ambient/underhood heat in general.

[TheSean]

Originally Posted by RyanWJ

I wonder if Ryan was actually talking about a problem with coolant temp, or heat soak in general. Heat soak doesn't really seem to be affected as much by coolant temp as much as it does ambient/underhood heat in general.

you should be able to see the connections between these two things.

[RyanWJ]

Originally Posted by TheSean

you should be able to see the connections between these two things.

Of course they're connected. Let me try to rephrase...

What I meant is that engine performance (or lack of) isn't just dictated by the temperature of coolant. IATs, fuel rail temps (especially in a returnless application), etc etc all come into play. From my limited experience, coolant temp DOES affect all of those (obviously), but general underhood (radiant heat, if you will), which is not just heat coming off the radiator/coolant hoses,etc seems to affect it the most. In other words, I think you could drop coolant temp 5, 10, 20 degrees, and still have a underhood heat issue. That being said, every application is different.

You're an engineer, and I'm just a guy who likes to drag a 4400 lb brick down the 'strip, so for all I know I could be talking out of my ass.

[N-Dawg]

Originally Posted by RyanWJ

Of course they're connected. Let me try to rephrase...

What I meant is that engine performance (or lack of) isn't just dictated by the temperature of coolant. IATs, fuel rail temps (especially in a returnless application), etc etc all come into play. From my limited experience, coolant temp DOES affect all of those (obviously), but general underhood (radiant heat, if you will), which is not just heat coming off the radiator/coolant hoses,etc seems to affect it the most. In other words, I think you could drop coolant temp 5, 10, 20 degrees, and still have a underhood heat issue. That being said, every application is different.

You're an engineer, and I'm just a guy who likes to drag a 4400 lb brick down the 'strip, so for all I know I could be talking out of my ass.

Neglecting heat dissipated from the radiator into the engine compartment, a large factor for underhood temps is how much heat your headers radiate. IAT's would probably be the most affected, which would then have the largest effect on your overall performance.

Really the OP seemed to be talking about an overheating issue, and then sort of slid into a 'this is a performance issue'. Unless your coolant temperature is getting above 235F (lol, arbitrary) at any point in the drive cycle, I believe increasing IAT's are the problem which canoot be solved by a thermostat swap. At that point it becomes changing Intake material and coating the exhaust material.

And Sean, that red-dotted line clearly crosses at 100 on the X-Axis, you damn troll.

[D's01Snake]

gay

[Pifer740]

I'm still heat soaked, baby.

[RyanWJ]

Originally Posted by N-Dawg

Neglecting heat dissipated from the radiator into the engine compartment, a large factor for underhood temps is how much heat your headers radiate. IAT's would probably be the most affected, which would then have the largest effect on your overall performance.

Really the OP seemed to be talking about an overheating issue, and then sort of slid into a 'this is a performance issue'. Unless your coolant temperature is getting above 235F (lol, arbitrary) at any point in the drive cycle, I believe increasing IAT's are the problem which canoot be solved by a thermostat swap. At that point it becomes changing Intake material and coating the exhaust material.

And Sean, that red-dotted line clearly crosses at 100 on the X-Axis, you damn troll.

After reading it over again, it does appear that he was talking about a IAT-related issue that was being amplified by rising coolant temps at a standstill. I also agree that insulation/coating various items is the best way to alleviate the problem.

I've VHT-coated most of my exhaust and intake manifold (did it for corrosion prevention more than performance), wrapped my coolant hoses in header wrap (so far so good although I am sure the hoses will fail sooner than in factory form) , and wrapped my intake tube (4" aluminum) with several layers of Design Engineering's Cool Tape. I have no proof, but it seems to help fight hot IATs.

The warm-up time with the wrapped hoses is WAY better, although I have seen no improvement in coolant temps. My next project is to insulate my fuel rails followed by wrapping the exhaust in DEI's exhaust wrap.

[N-Dawg]

Originally Posted by RyanWJ

After reading it over again, it does appear that he was talking about a IAT-related issue that was being amplified by rising coolant temps at a standstill. I also agree that insulation/coating various items is the best way to alleviate the problem.

I've VHT-coated most of my exhaust and intake manifold (did it for corrosion prevention more than performance), wrapped my coolant hoses in header wrap (so far so good although I am sure the hoses will fail sooner than in factory form) , and wrapped my intake tube (4" aluminum) with several layers of Design Engineering's Cool Tape. I have no proof, but it seems to help fight hot IATs.

The warm-up time with the wrapped hoses is WAY better, although I have seen no improvement in coolant temps. My next project is to insulate my fuel rails followed by wrapping the exhaust in DEI's exhaust wrap.

From what I know, the VHT stuff does not do anything appreciable for insulation, but it looks nice.

Wrapping the coolant hoses with header wrap? Interesting. Keeps the heat in the hoses better I guess. Of course it won't help decrease coolant temps, it would increase them, if anything. Wrapping the hoses won't increase the efficiency of your heat exchanger.

Wrapping the Intake tube is a good idea, look to Thermo-Tec if you want a better solution. It wouldn't be hard to get Before and After IAT data from a simple IR thermometer or a scan tool .

For exhaust, plasma/ceramic coating is the way to go if someone has heat problems. From what I've read, wrapping exhaust isn't worth the time and money when compared to it. Getting your headers coated by Zircotec, Jet Hot, etc would be pretty awesome.

Fuel rails? I think you hit the law of diminishing returns there. If you have wrapped your hoses and coated your exhaust, your engine compartment temperatures should be vastly lower.

[TheSean]

two comments:

1) I wrapped my exhaust with doubled DEI wrap and in the parts I didn't want to radiate, with puffy ceramic insulation (the kind that lines steam burners) and it did wonders for keeping everything under the hood cooler. In my case it wasn't about IATs or what have you, it was melting wires and being able to pull things apart quickly. Of course, my car isn't really practical. I've also seen a not-negligible drop in temps from ceramic/powder/whatever coated. Also this nonesense of 'don't wrap ceramic headers' seems silly to me, not only overkill but a severe waste of money.

2) Fuel temps are a very good place to play with insulation. This affects tuning like crazy. In some cases, hotter fuel can be better; in some, cooler is better. But overall, consistency is crucial. I don't think fuel temp is considered in any ECU programs, and I wouldn't want to try to add that to the soup.

3) Yeah, I said two, sue me. Wrapping the intake could be useful but I'm with Neil, not really sure the tube is doing a lot of heat addition; I'd say most is coming from the hotter air being pulled from the engine bay. Even ricers know a 'cold air intake' is the first step to better performance (and a better filtering system, but that's another thread).

[RyanWJ]

The VHT does look nice. I did everything downstream of my exhaust manifolds in flat black. In the parking lot section I have a pic of my intake manifold (composite plastic) painted in flat aluminum , looks awesome for a rattle-can paint job IMHO.

My upper coolant hose in particular sits right next to my air filter, so my thinking was that the hose radiates heat, thus increasing IATs (how much, who knows). If that radiant heat energy is now staying as energy IN the hose as opposed to radiating outside of it, in theory it should help. My coolant temps seem about the same, maybe a hair higher, but not nearly enough to negate the benefits I've seen.

The fuel rails do get excessively hot in most returnless systems (such as mine). The plan is to insulate them with multi-layered insulation not all that dissimilar to what Sean described. I have seen some question the concept of "cooling" the fuel, but I have seen independent dyno results of cooling fuel rails and there was gains to be had. I suppose it depends on the application. Sean is also correct that it does affect tuning (for one, it stabilizes the AFR between cyl to cyl for those that previously got the hottest fuel) .

Bottom line though, these insulators have drastically altered the underhood heating going on. Money well spent.

Originally Posted by N-Dawg

From what I know, the VHT stuff does not do anything appreciable for insulation, but it looks nice.

Wrapping the coolant hoses with header wrap? Interesting. Keeps the heat in the hoses better I guess. Of course it won't help decrease coolant temps, it would increase them, if anything. Wrapping the hoses won't increase the efficiency of your heat exchanger.

Wrapping the Intake tube is a good idea, look to Thermo-Tec if you want a better solution. It wouldn't be hard to get Before and After IAT data from a simple IR thermometer or a scan tool .

For exhaust, plasma/ceramic coating is the way to go if someone has heat problems. From what I've read, wrapping exhaust isn't worth the time and money when compared to it. Getting your headers coated by Zircotec, Jet Hot, etc would be pretty awesome.

Fuel rails? I think you hit the law of diminishing returns there. If you have wrapped your hoses and coated your exhaust, your engine compartment temperatures should be vastly lower.

Originally Posted by TheSean

two comments:

1) I wrapped my exhaust with doubled DEI wrap and in the parts I didn't want to radiate, with puffy ceramic insulation (the kind that lines steam burners) and it did wonders for keeping everything under the hood cooler. In my case it wasn't about IATs or what have you, it was melting wires and being able to pull things apart quickly. Of course, my car isn't really practical. I've also seen a not-negligible drop in temps from ceramic/powder/whatever coated. Also this nonsense of 'don't wrap ceramic headers' seems silly to me, not only overkill but a severe waste of money.

2) Fuel temps are a very good place to play with insulation. This affects tuning like crazy. In some cases, hotter fuel can be better; in some, cooler is better. But overall, consistency is crucial. I don't think fuel temp is considered in any ECU programs, and I wouldn't want to try to add that to the soup.

3) Yeah, I said two, sue me. Wrapping the intake could be useful but I'm with Neil, not really sure the tube is doing a lot of heat addition; I'd say most is coming from the hotter air being pulled from the engine bay. Even ricers know a 'cold air intake' is the first step to better performance (and a better filtering system, but that's another thread).

Sean, whats your exhaust fabricated from? 321 SS?

I'll eventually wrap my exhaust downstream of the manifolds to see if it helps with scavenging.

[TheSean]

Well it's cast 308 with .120"" walls before the turbo and 316 4-inch, 1/16" wall after. My EGTs go pretty high, I measure them at the exhaust port, at the turbo inlet and at the outlet. There's also a big kevlar blanket over the turbine housing (like a big diaper). I melted a set of injector wires (my car's engine bay design is a clusterfuck) and rewired everything but I still have protection for the wires in the form of thermal tape and AL heat shields.

More on fuel temps later...

[N-Dawg]

Originally Posted by RyanWJ

The fuel rails do get excessively hot in most returnless systems (such as mine). The plan is to insulate them with multi-layered insulation not all that dissimilar to what Sean described. I have seen some question the concept of "cooling" the fuel, but I have seen independent dyno results of cooling fuel rails and there was gains to be had. I suppose it depends on the application. Sean is also correct that it does affect tuning (for one, it stabilizes the AFR between cyl to cyl for those that previously got the hottest fuel) .

I'll eventually wrap my exhaust downstream of the manifolds to see if it helps with scavenging.

In your returnless system, what is causing "High Fuel Rail" temperatures? Do you think it is the radiant heat from exhaust/heated air, or do you think it is more from the giant heat pump in the system known as your fuel pump? The fuel pump (AFAIK) in your returnless system is being PWM'd of the high side of the PDB. I am interested in hearing more of what Sean knows about the effects of fuel temperature on AFR/Performance.

Isn't scavenging a function of camshaft profile then headers/collector(s)? Wrapping your downstream exhaust shouldn't net you more scavenging then, perhaps just greater temperatures within the exhaust thus greater exhaust velocities.

308 and 316? You rich boy. When are you going to man up and grab some Ti-exhaust? Cut your Thermal Conductivity in half.

[RyanWJ]

Originally Posted by N-Dawg

In your returnless system, what is causing "High Fuel Rail" temperatures? Do you think it is the radiant heat from exhaust/heated air, or do you think it is more from the giant heat pump in the system known as your fuel pump? The fuel pump (AFAIK) in your returnless system is being PWM'd of the high side of the PDB. I am interested in hearing more of what Sean knows about the effects of fuel temperature on AFR/Performance.

Isn't scavenging a function of camshaft profile then headers/collector(s)? Wrapping your downstream exhaust shouldn't net you more scavenging then, perhaps just greater temperatures within the exhaust thus greater exhaust velocities.

308 and 316? You rich boy. When are you going to man up and grab some Ti-exhaust? Cut your Thermal Conductivity in half.

I again stress that I'm not an expert nor an engineer but I believe the fuel rails get hot because of both radiant heat (mainly from the aluminum heads they sit over) and because in a returnless system, vaporized or excess fuel has nowhere to go.

I've always heard scavenging being used synonymously with exhaust design/theory (although I know it is also taken into consideration when designing a cam profile). I have very short exh manifolds that already are heat shielded (think of a really efficient log manifold), so wrapping downstream of that shouldn't be too inefficient. I think if you increase exhaust velocity anywhere in the exhaust system (obviously further upstream is ideal) , you stand to improve scavenging as a whole.

This is some really good tech being discussed,i am probably gonna sticky this thread.

[TheSean]

Originally Posted by N-Dawg

In your returnless system, what is causing "High Fuel Rail" temperatures? Do you think it is the radiant heat from exhaust/heated air, or do you think it is more from the giant heat pump in the system known as your fuel pump? The fuel pump (AFAIK) in your returnless system is being PWM'd of the high side of the PDB. I am interested in hearing more of what Sean knows about the effects of fuel temperature on AFR/Performance.

Isn't scavenging a function of camshaft profile then headers/collector(s)? Wrapping your downstream exhaust shouldn't net you more scavenging then, perhaps just greater temperatures within the exhaust thus greater exhaust velocities.

308 and 316? You rich boy. When are you going to man up and grab some Ti-exhaust? Cut your Thermal Conductivity in half.

Returnless is a strange concept to me. I guess it was for emissions (less vapor returned to the tank)? but F that mess.

Sure scavenging will depend on the exhaust pressure (=velocity=temp but I'd be surprised if 100 degrees hotter exhaust made any more power) but I wouldn't know if geometry and a backpressure balance would give better performance or not. Depends on the application (default answer for everything) I suppose. I don't really have an option, but with more room and different goals (mine being total power) there's certainly room to play with that. Looking at it from a simpler POV, the hotter the exhaust, the less of that energy you've put into the piston, but such are the facts of combustion.


Quick facts on fuel temp, I'll go on a longer diatribe another day: In the combustion cycle, you're going to bring the fuel up the vapor temperature before it will combust (this is how droplet reactions work) which takes energy (heat energy) and lowers the total amount of energy you get out of your fuel, in addition to raping the efficiency of the combustion. This is why getting the best fuel injectors is important, but even the best case scenario is still droplet combustion. So, if you add [exhaust] heat to your fuel up to the point of it being near the vapor temperature, you will get a tiny decrease in density (seriously, it's a liquid) but it will vaporize a lot easier when you drop its pressure across the injector. This should cause a more efficient combustion. They used to sell, maybe still do, little cans that cross-flow heated fuel with coolant. But on the other hand, if you let the heat get out of hand you will vaporize it and that's bad for a lot of reasons.

[N-Dawg]

Originally Posted by TheSean

Looking at it from a simpler POV, the hotter the exhaust, the less of that energy you've put into the piston, but such are the facts of combustion.


Quick facts on fuel temp, I'll go on a longer diatribe another day.

Oh god. Yes, but that is a function of ignition timing.

I move that we have a discussion on fuel/fuel temp in another thread. Sean, would you do the honors of starting that with a "longer diatribe"?

[gouldie]

http://www.circletrack.com/enginetec...ine/index.html

fuck all of this