which oil , what viscosity

Indycars

Administrator
Staff member
Thanks for the link, I was glad to see the following in his article. I use 10w30 Royal Purple HPS that has the higher ZDDP levels in my roller engine.


Oil.jpg
 

NewbVetteGuy

Well-Known Member
I frequently hear the younger guys say that they want to run a 160F t-stat because they hear that cooler air is denser and holds a higher oxygen content, and while thats true the fuel air mix in an intake port can very easily be traveling 100-300 feet per minute, that means that in a typical intake manifold at lets assume a low cruise speed the time it takes an individual cubic inch of air to be blended with fuel mist and too move from the carburetor or throttle body to combustion chamber could easily be less than 1/20 of a second, how much heat transfer do you thinks accomplished in that time span?
I just came across this thread again and after watching Engine Masters Season 4 Episode 43 they did some very relevant testing on engine coolant temps vs. manifold temps and whether and why cold coolant makes power.

The test:
598 cubic inch BigBlock Chevy

Test #1: Cold coolant temps (135F coolant): 790 ft lbs @ 5,100 RPM; 854.8 hp @ 6,200 rpm
Test #2: Hot coolant temps (200F coolant) 744.2@5,100; 836.1 hp @ 6,300 RPM

+15.8 ft lbs and +18.7 hp with the colder coolant.

The interesting part of the test is that they were testing the intake air temps in the runners and the 65 deg F increase in coolant temps only resulted in a +3 deg F increase in the air temps, largely for the reasons that Grumpy detailed in the test. (There's not much time to change temps; and the evap cooling capacity of the fuel helps reduce the air temps, too.)

Their working theory is that the colder chamber temperature creates a bigger pressure differential across the intake valve so they are getting greater airflow into the cylinder / across the intake valve when running cooler coolant temps vs. hotter coolant temps.


In Season 7 they go back and test the impact of cold vs. hot fuel, which makes a much smaller difference on the 464hp SBC 383 they did that test on. (+9 hp and +3.3 ft lbs improvement with cold gasoline vs. warm gasoline).

-Not related to oil viscosity, but very cool none-the-less (pun intended).

I tried to take screenshots of the dyno charts to share but my Engine Masters subscription is through Amazon Prime Video and they have DRMed the crap out of all their shows and you can't take screenshots in any browser any more... ;-(

Adam
 

Indycars

Administrator
Staff member
That's very interesting, but how doable is 135°F coolant temp or anywhere close ?

Have you tried pausing the video and using the Windows Snipping Tool?
Just click on the start button and type "snip" it should appear for you to click on. Then just drag a rectangle border around what you want to capture. If you like a Colored border in your capture, then use the "Options" first.


1672938013943.png
 

NewbVetteGuy

Well-Known Member
That's very interesting, but how doable is 135°F coolant temp or anywhere close ?

Have you tried pausing the video and using the Windows Snipping Tool?
Just click on the start button and type "snip" it should appear for you to click on. Then just drag a rectangle border around what you want to capture. If you like a Colored border in your capture, then use the "Options" first.


View attachment 17400
135F coolant obviously isn't remotely "doable" on the street, obviously. BUT, it does show that there's value in cold coolant temps with actual numbers; especially relevant in drag racing situations. Those cold coolant temps can help with power and detonation resistance if running on pump gas. (It also shows why so many Dyno operators run the dynos with coolant temps from the 140s-160s.... -I've never seen a Westech Performance Dyno video running at >160F coolant temp since I started paying attention to and looking out for them.)

Those electric water pumps and cooling fans to keep cooling down the coolant between runs has been proven to be a good idea.

All the advice from Stewart and Circle Track racers to improve cooling and coolant flow rates result in cooler chamber temps and are a good idea, too and seem applicable to actual street use and other forms of racing, though. (High flow pump, high flow thermostat, high flowing fans, good shrouds, etc...) A high silicone piston alloy with less expansion and potentially abradable skirt coatings to prevent wear and piston rock at lower temps could be part of the "recipe" for tiny gains and keeping longevity high while doing it.

-Just nice to see a test focused on one particular area of theory that's been debated for so long.


I definitely used the snipping tool and full screenshots. I also tried Chrome and Edge browser. The browsers' executables can opt into windows features that prevent the screenshots. -I need to try the "SnagIt" screen capture software, as in the past it has not "respected" / utilized the windows DRM / process protection and screenshot restrictions built into the OS and it might be an easy way around it. (I've got a deep and wide background on Windows security features and ways around them, I just didn't have more than 2 minutes to put towards it. I'm sure there's a solution. Maybe even an alternative browser would work, but Amazon should be blocking browser clients that don't respect their DRM; not that an intentionally browser client couldn't said a fake client string identifying as a different browser -I just don't know enough about the content protection mechanism that they're using. The screenshot restriction feature I think will be the easiest to get around.)


Adam
 

NewbVetteGuy

Well-Known Member
What do you guys think about using one of the magnetic heaters / block heaters to reduce coolant or engine oil warmup times?

I'm not sure whether they'd OVER HEAT things or not, but it would be SO easy to just keep one magnetically attached to my oil pan and plugged into one of those Alexa controlled outlet plugs and just tell Alexa to start pre-heating my oil sump a bit before I take the Corvette out for a drive.


Adam
 

Indycars

Administrator
Staff member
Sounds like a pretty cool idea for the winter months especially since your in Seattle. Will you be able to get it on and off without jacking the Vette up?
 

NewbVetteGuy

Well-Known Member
Sounds like a pretty cool idea for the winter months especially since your in Seattle. Will you be able to get it on and off without jacking the Vette up?
No problem from the side. I can't get under it from the front, though. -I have a pace car front spoiler like came on the 78 Pace Cars AND I extended the front air dam down another 2" AND have semi-coilovers at their lowest setting right now so it's LOW to the ground in the front. (I can't get my jack under it from the front anymore.)

I actually use Alexa for a bunch of stuff in my garage; I love it. I've got my air compressor connected to an Alexa enabled outlet and my bench light, my beer kegerator's temperature AND I even have a fan that pushes cold air up into the tap to chill the tap to avoid beer foaming on the first pour- I built an automation to schedule it to start chilling at the kid's bed time and to then turn it off after my bed time; lol!

I love being able to ask alexa to convert between inches and millimeters because I can never remember metric wrench sizes. Useful for random stuff like that.

Adam
 
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