Ported stock mani good for 550hp+, so whats the point of headers?

[cordes]

I've been in boost for at least an hour at a time. I'm sure we did that going up the rockies in the CSX. One stint when I was driving I just tried to keep it down to 4 or 5 PSI for pretty much the whole tank if I'm not mistaken.

[Ondonti]

I did on the Reliant, can't remember the results though. Engine was setup to shut down if the cooling system exceeded "x" pressure indicating the head was lifting and pressurizing the coolant system.

I like this a lot. Seen quite a few versions including measuring at the overflow hose but this would be the fastest reacting. Hobbs?

https://en.wikipedia.org/wiki/Pascal%27s_law

'Pressure in an enclosed liquid system is the same everywhere'. Just wanted to get that out there. Good thing brakes work! Measuring pressure in different places is pretty meaningless. Measuring temperature is useful if its telling you where the boiling is happening.

You can't overpressurize a system with a water pump. It doesn't create an overall pressure increase in the system.

Try putting your radiator cap at the beginning of the coolant outlet house and tell me how you avoided the extra pressure drop of the hose and radiator tank and core?
There is a reason they are always located after the radiator core.
http://stewartcomponents.com/index.p...ormation_id=14

[mopar-tech]

I like this a lot. Seen quite a few versions including measuring at the overflow hose but this would be the fastest reacting. Hobbs?

Yes, screwed right into the head above the thermostat opening.

[GLHS60]

Speaking of high speed and boost, I can cruise on level ground, zero boost, at almost 110 mph in my Super 60 Omni, A 555.
Anyone else ever experiment with top cruising speed at zero boost??

Thanks
Randy

[cordes]

Speaking of high speed and boost, I can cruise on level ground, zero boost, at almost 110 mph in my Super 60 Omni, A 555.
Anyone else ever experiment with top cruising speed at zero boost??

Thanks
Randy

I have. Nothing super serious testing wise, but I know that I've gone 100-105 in a 3.85FD daytona at 0 boost before.

[going4speed]

Zero on the boost gauge? I still think there is some boost there with the gauge at zero.

[GLHS60]

I have. Nothing super serious testing wise, but I know that I've gone 100-105 in a 3.85FD daytona at 0 boost before.

Almost exact same speed so we must both have exact same faulty boost gauges !!

Have to check our vacuum gauges next.

Thanks
Randy

[Ondonti]

Zero on the boost gauge? I still think there is some boost there with the gauge at zero.

Well, this would be the turbo making the throttle plate pass more air then it should at a given throttle opening, especially with some load on the engine.
Boost measured at the turbo or at the manifold :P

Speaking of high speed and boost, I can cruise on level ground, zero boost, at almost 110 mph in my Super 60 Omni, A 555.
Anyone else ever experiment with top cruising speed at zero boost??

Thanks
Randy

I am sure I will hit the speed limiter before that happens. :/

I want to see a study on how turbo size affects the same exact engine on the same car for zero boost cruise.

[GLHS60]

I have no speed limiter and my max cruise control speed has been increased to about 110 MPH.

I want to see the same study too. A friend showed me a study where the turbo shaft itself has approx. 50 LB/FT available to harvest!! The newer Detroit Diesel actually has a device to harvest the otherwise wasted turbo shaft energy.

Thanks
Randy

[Vigo]

Try putting your radiator cap at the beginning of the coolant outlet house and tell me how you avoided the extra pressure drop of the hose and radiator tank and core?
There is a reason they are always located after the radiator core.

That's why pascal's law includes the word 'enclosed'. Because it doesn't apply when the system is 'open'.

[puppet]

Holy off course thread. Seems to be a lot of confusion on how the cooling system works or I'm not understanding some of the other's points being made. The centrifugal pumps used don't add an appreciable amount of pressure. They do, of course, but not like a positive displacement pump. Once the system reaches operating temp (and pressure) the cap regulates the pressure in the system. Lower pressure cap = lower boiling point. Higher cap rating = higher boiling point which is better but as zin pointed out comes with potential issues such as block integrity (gaskets, plugs, seals). At any rate, once the system reaches the designed temp/pressure the pump just circulates the coolant.

[Vigo]

It makes sense to me. My point is you could measure pressure anywhere in the system and still get a valid reading, but putting additional pressure sensors in different locations would not give useful data. To find out in what AREA the coolant is boiling you would need to measure temperature, not pressure. But, i feel like we have a pretty good idea of what happens in the engine already. Knowing where coolant gets pumped in, where it's released at the thermostat, and the fact that the #4 cooling mod lessens knock counts in that cylinder, it pretty much seems like a linear heat rise from cyl 1-4 with stagnant coolant in the rear corner behind #4. I'm interested in what Ondonti has mentioned elsewhere about altering water flow into the head by modifying the headgasket coolant orifices, but as you say it's off-topic for this thread.

[mopar-tech]

My point is you could measure pressure anywhere in the system and still get a valid reading, but putting additional pressure sensors in different locations would not give useful data.

I have found it to be useful when trying different restrictor sizes.

If you are running a stock cooling system with slightly elevated power levels then this discussion need not apply. I found on the Reliant there were LOTS of issues with coolant flow and had to make changes to address them so the engine would live at the power level it was running at.

The next version will be even more radical, I'll need to do some mock ups before proceeding.

[Reaper1]

Why not use some waterproof temp sensitive paint on the coolant side of the cylinder bores (applied with a Q-tip...etc.)? I know it's a serious PITA to pull the head, but if you are popping head gaskets and pistons due to coolant related issues you are going to be doing it anyway.

Another thing you could look into is thermocouples...attach them inside the coolant passages then run the leads through a modified expansion plug and do some data recording.

By increasing the boiling point as well as reducing the coolant's surface tension to reduce the chances of bubbles even forming you can help prevent hot spots.