z_speedfreak

iTrader: (3)

true, I like hearing dif points and seeing LT1 gurus debate each other! thats about the only time they really divulge as much info as they did here, other wise its just quick blurbs or you should do this or that but wont go into depth about it.

Jon A

I guess you missed the thread which was magically deleted after I provided a bunch of "performance data." In it, he attacked my integrity, which gets you put on my shitlist real quick.
While I have shown what can be done with the stock cubes in a streetable, hydraulic configuration, I actually advise people doing builds to add cubes if they can. Unless it's a budget build using the stock bottom end, cubes only help.

Even if one only makes the same peak power, the area under the curve is increased making for a faster car. The low end torque helps drivability and makes for a more fun street car.

And if one does want to spend more money on the heads, the cubes will allow one to make more power while staying under the 7000 RPM PCM limit.

The only reason I didn't stroke mine was a displacement/rulebook issue for a racing class. Since all I care about now is trying to win overall (being the fastest car out of all classes at the track that day) I wish I had the extra cubes.
Unfortunately, it often seems with some of the loudest people in the LT1 world, that only users of one brand are allowed on the team. If I lied and said my heads were done by Dwayne's favorite brand, I'd be one of his heroes and he'd post my dyno sheet all over the internet and try to cite it in every conversation. But since they're from a brand he doesn't like, he attempts to dismiss, discredit, question its validity, authenticity, etc. That does a disservice to the LT1 world. It slows progress and only tries to ensure that nobody ever makes any more power than he does....

Jon A

In a closed loop system, the faster the fluid goes through the heat exchanger the more total heat is removed. It's a simple law of heat transfer that doesn't change. It had to be something else causing the issue.

The most common cause, and where the "old wives' tale" came from, was circle track and roadracers in the old days, mainly using SBC's. They found the same thing when they removed their thermostats and came to the same conclusion causing them to run restrictor plates in place of the thermostats to fix the issue.

They mis-diagnosed the problem. As with many engines, when one removes the thermostat downstream of the water pump leaving only a low pressure radiator in between, the head pressure on the pump is reduced. This head pressure is important because pumps of this type tend to cavitate when they have nothing "pushing against" them. The reduction in head pressure reduced the cavitation threshold to the point it would occur at high RPM.

When the water pump cavitates it does all sorts of bad things. Besides creating heat of its own and forming bubbles in the fluid, most importantly it stops pumping efficiently--the flow rate is reduced. So by reducing the restriction, the end result was slower moving coolant...and naturally, higher engine temps.

Historically most engines have had a simple thermostat on the exit side of the engine so similar results can be expected.

Engines like the LT1 with "dual acting" thermostats are an entirely different animal as removing the thermostat will screw up the way the whole cooling system operates. I'm not familiar with the engines you mention, but that is another possibility.

z_speedfreak

iTrader: (3)

O i believe what your saying for these engines and maybe thats even true with diesel trucks? But the engines im talking about are way bigger than truck engines, theres no radiator with air being forced thru it or even fans, there either keel cooled or have a heat exchager with a steady, non rpm related flow of sea water going through them. I know guys that had their tstats fail and take it out to finish the week before putting a new one in and the same thing happened and that was on a cummins KTA1150 so way dif than an old 12-71

Jon A

OK, that's definitely much different. Sounds like it's not a closed loop system...I have no idea how any of that stuff works (not a boat guy), so I'll take your word for it.

z_speedfreak

iTrader: (3)

Not nit pickin or nothin man, just makin an observation

OVA1

iTrader: (12)

What an excellent discussion.

I was momentarily buoyed by your noting that moving fluid through the heat exchanger more quickly must remove more heat…

As this has always been my operating theory.

Then you note that the LT-1 is a dual system, further noting the requirement for the thermostat, which can only slow the rate of exchange.

Jon, if you've the time, would you explain the nature of the LT-1 Cooling system, or direct me to a write-up of same? I should point out I am familiar with such to the extent of the 'reverse cooling', wherein the heads are cooled first, ahead of the block… and that this was what provided the LT design to increase compression, without fear of detonation on pump gas. I guess my question is more specifically oriented around the water pump and how the T-stats present 'directs' the flow…

I have always favored no stat… which I should point out, I am located in SW FL, where we're rarely concerned with freezes or such other issues related to the arctic regions north of Ocala, so this is a continual point of debate with the guys around the shop.

BTW, just took a look at your Z, beautiful car, sweet setup. Well done sir…

Jon A

Yes, while it may seem counter-intuitive, that's the way it works. You pump the water through the radiator faster and it won't cool it as much. Huh?

Yes, that's actually what makes it work better. You increase the average temp of the water in the radiator, which increases the average delta T between the water and the air moving through the radiator, which increases the overall heat transfer coefficient of the radiator...which allows it to remove more heat per unit time.

In a closed loop, if your heat exchanger is removing more heat, you reduce the average temperature of the water in the loop.

Though the radiator isn't cooling the water quite as much, it's cooling a lot more of it. That's the key. When you pump more water through the engine, it can remove more heat per degree of temperature increase.

So even if the water is entering the engine a few degrees higher, with an increased mass flow rate it can actually remove more heat from the engine while exiting at a lower temp than slower moving coolant.

The way the thermostat is set up in the LT1, I'd say it's more accurate to say it "directs" flow, instead of slowing it. When the engine is cold it allows coolant to circulate throughout the block without allowing flow through the radiator. When the engine is hot, it forces the water to go through the radiator.

It has been a while since I've looked at this stuff in detail, but the way I remember it is if the thermostat is completely removed the re-circulation path is never closed off so I don't think it will force as much coolant through the radiator as an "open" LT1 thermostat properly installed will. In any case, with the quality 160 degree stat readily available there's really no good reason to run one of these engines without one.
The best writeup I've seen on the LT1 overall is the SAE paper 920673. You can buy it here: http://papers.sae.org/920673/
Thanks, man. I've been screwing with the car for a long time, and winning fastest time of the day at the track last weekend by a mile was some sweet payoff for all the hard work.

OVA1

iTrader: (12)

Thank you.

stmz28

iTrader: (9)

Any one ever try or heard of this radiator

http://www.speedcooling.com/Radiator...r/prod_33.html

GermanLSX

Hey guys! Excuse the late reply. Been out because of work. Great news though. Got the radiator and water pump installed last week, and have to admit im impressed. No matter what I throw at the car she stays just a hair over the first 160 mark. Im assuming she runs 165-175 from what I read. I get off the highway and she stays put in her temperature like a loyal girl. So I dont have to worry about her being in heat



Hey no problem. The booster is stock replacement. I figured I already have enough braking power with the Anti Lock. Pads, rotors, and calipers are all upgraded. The master Cyl is from a old buddy that works on cars and he installed an upgraded one for me. Other then that the car has really out performed the stock braking system for the past 7 months or so.

I am getting more interested in 1/4th times. Not sure what she’ll run though. I hear high 13’s or low 14’s. Get some times or at least some dyno numbers mate. She will like you to know what she is capable of doing

Jon A: Couldnt agree with you more. I havent read all your posts thoroughly, but did read the chart. Interesting you brought that up. Im sure you already mentioned this and most already know this, but not only the faster the cooling system is running the better it cools, but the higher the RPM the more energy it creates which in turn the hotter the engine gets. So in turn more rpm, more cooling, equal efficiency depending on many variables like car speed, what liquid coolant, fans, rad, ect. Interesting post for sure. Ill have to read it some more.

As my car I couldn't praise enough how satisfied I am with the system. Did an oil change along with the new WP, and rad and ran her pretty hard [4600-5500rpm] the past few days and her gauge didnt move a soul.

Call me delusional which what im about to say it most likely all in my head, but she feels like she gained a couple extra HP. I did a little experiment; Checked the intake and it was only warm when I got to work. Before it got so hot I could fry an egg. The intake elbow was room temperature, and the WP is obviously always hot. I know stock radiator is enough to cool 400hp but the reverse flow cooling really likes the new one. Now once I start modifying the car I wont have to worry about the radiator cracking.

GermanLSX

That looks a lot like the one im running now.

pillarpod

Guys running the BeCool rad, you guys using stock or EWPs?

Jon A

That's the same brand I got for my Trailblazer. I would guess it comes out of the same factory as the Champion so quality should be similar. With two 1" rows it should cool a hair better. They also usually come with a stacked plate tranny cooler which is better than the concentric tube type.

Jon A

I'm running stock.