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Isn't LG and G-Speed the same company/family? Or no?
H3LL NO!!!!
Let's put it this way. Say that a company has an individual that has all the talent but isn't the owner or front man or what ever you want to call it.
That talented individual decides to go out on their own and create their own new company.
The previous company still benefits from the reputation they have attained through the work of the talented previous employee. But future en devours lack the same quality and craftsmanship as when the talented employee was there.
The new company formed by the talented individual brings to market many new, exciting and quality components.
Let's put it this way. Say that a company has an individual that has all the talent but isn't the owner or front man or what ever you want to call it.
That talented individual decides to go out on their own and create their own new company.
The previous company still benefits from the reputation they have attained through the work of the talented previous employee. But future en devours lack the same quality and craftsmanship as when the talented employee was there.
The new company formed by the talented individual brings to market many new, exciting and quality components.
Over the past two months or so, we've been working with Operations's 2015 Z06 Z07 to solve the overheating problems that plague these cars. This thread will detail our development efforts as we narrow in on a solution.
Since we're located at the Motorsports Ranch in Cresson, TX, we've got the ideal thermal testing environment literally in our backyard. For those of you not familiar, OEMs come here on a regular basis in the late summer to stress test cooling systems on track in the 100°+ heat. Our goal for this car is to run a full HPDE session at Circuit of the Americas without overheating. For us (and many other racers) that means more than just not going into limp mode. The car will run with water temps of 235° or more, but we don't consider that acceptable performance for a track car.
As detailed in this thread here (https://www.corvetteforum.com/forums...r-results.html) the first step was a DeWitt radiator and oil cooler. While it made a difference, it was nowhere near enough to solve the problem.
To give a brief history, the car ran at COTA in Sept. 2015 in 100° weather. Water temps were north of 260° and oil temps were almost 300°. The car lasted 6 laps before it went into limp mode and came back in. That was with the DeWitt Gen1 radiator.
In Feb. 2016 in 70° weather, the car ran almost identical temps as the previous summer, but was able to go an extra two laps before coming in.
So while the DeWitt radiator is a step in the right direction, it's clearly not enough for a track car.
The first step in this phase was to install "cheek mounted" heat exchangers for the supercharger.
This involved cutting up the bumper, so for our trials we bought a new bumper so as not to ruin Operations' until we had a final solution.
We knew we were facing a significant challenge. At the risk of oversimplifying the problem, this car simply cannot dissipate enough heat for the power it makes. "X" amount of air entering through the front can only dissipate "Y" amount of heat, regardless of heat exchanger efficiencies, packaging, etc. That fundamental theory is why we chose the LG Motorsports kit.
To attempt to understand the behaviors of the myriad heat exchangers in this car, we set up an Aim MXL2 with eight temperature sensors throughout the engine bay to log various fluid and air temperatures.
We noticed a while back that the C7 Stingray has the same radiator (down to the GM part number) as the Z06. Doesn't really make sense, given the extra 200hp of the Z06, and is most likely part of the problem. So to increase the overall cooling capacity of the system, we added a second auxiliary radiator in front of the main radiator. This radiator measures 18" x 8.5". To monitor the performance of this radiator, we added water temp sensors at the engine inlet and outlet, as well as between the two radiators. We also are monitoring air temperatures in front of all the radiators, between the auxiliary radiator and main radiator, and behind the main radiator. With the two water temperature sensors monitoring the blower coolant temps, we filled up the 8 analog channels we had on the MXL2. It's not as thorough as an OEM's vast array of thermocouples, but we also have a small fraction of their R&D budget.
The eight sensors and extra heat exchangers were arranged like so:
We also fabricated and added a much larger reservoir above the intercooler pump to give it as much of a chance of success as possible, given the increased load. We're already worried about getting heat out of the system fast enough, we don't want to be fighting a cavitating pump. You can also see the two intercooler temperature sensor blocks in the lines just below the reservoir.
Once we got all of this installed, we went testing. We drove one session Thursday afternoon (6/30), but we were fighting the active handling and Ediff the whole time. We were never able to run a full lap "at speed," but we got some very useful data nevertheless. Here's what we learned.
Here's the engine coolant temps throughout the engine bay. The red line is coolant coming out of the engine, purple is between the two radiators, and blue is returning to the engine. You can kind of tell the temperature drop isn't split evenly between the two, especially considering the larger size of the main radiator. More on that in a sec.
Here's blower coolant temps. Same color scheme, red is coming out of the engine, blue is returning.
What was really interesting, though, was the air temps.
Blue is air coming in through the grill, purple is between the two radiators, and red is out the back of the main radiator.
To make things a little more easy to interpret, here's the water temp differential across all three. Calculated by subtracting outlet temp from inlet temp:
And air temp differentials across the main and auxiliary radiators:
Looking at those graphs, it's pretty clear the auxiliary radiator is hurting airflow through the main radiator. Although the overall cooling performance has increased, the total lack of air temp change across the main radiator tells us it's not doing near enough.
What's happening is the hot (235°) coolant is hitting the cool (95°) air coming in across the auxiliary radiator. When that happens, the air is heated up to about 180°, and the coolant is cooled to about 180°. The end result is zero heat transfer across the main radiator.
So for our next test day, we need to rethink how we're running coolant through the auxiliary radiator. It seems like the extra capacity is helping, but there's a lot of improvement left.
Jake
Nice work guys thanks for the detailed write up. Just one question, have you tried to change the stock thermostat out and put in a 160 degree, and reprogram the fans, it made a huge difference in my C5?
Yes. We will sell any of the parts to our kit a la carte. Send us an email sales at gspeed.com and the sales team will get you the part numbers and prices for you.
2014 NASA Texas TT1 Champion
2015 NASA Texas ST1 Champion
2018 NASA TTU & TT3 National Champions
2019 NASA ST2 National Champion
2019 NASA Texas TT2 Champion
2020 SCCA Majors COTA GT2 pole sitter
2020 SCCA Trans Am Road Atlanta SGT Winner
2022 NASA National Champion ST2
2023 NASA National Champion ST2
2023 NASA National Champion TT2
Did you ever try a V-mount for the main radiator area? Turbo import guys have been doing it that way for a long time to help lower temps. It is more efficient than stacking coolers.
Also, running without a hood and using proper hood ducting is not equivalent. The airflow over the vents will suck heat out. Without a hood, there is positive pressure over the entire engine bay keeping the heat in. You could find out quickly by just cutting some holes in the front of the hood.
Did you ever try a V-mount for the main radiator area? Turbo import guys have been doing it that way for a long time to help lower temps. It is more efficient than stacking coolers.
Also, running without a hood and using proper hood ducting is not equivalent. The airflow over the vents will suck heat out. Without a hood, there is positive pressure over the entire engine bay keeping the heat in. You could find out quickly by just cutting some holes in the front of the hood.
Hello, yes. If you read the thread, you would see that we did indeed V Mount the radiator, and transmission coolers. If you read further, you would know that we we have a high temp heat exchanger (oil) and low temp heat exchanger (blower) and stacking them we had enough delta in temperature between the two systems to stack them and see temps we wanted.
Also, as for the hood removal, its a data point, and thats it. Was it right? We dont know. But it didnt work. We also removed the hood grill, and put a huge wicker in front of the opening to create a low pressure, in hopes of getting more air out.... but it didnt work either.
Yes I apologize it was 18 pages so I didn't read it all. I actually assumed you had tried any idea I might suggest given the level at which you are functioning. I would still try additional vents toward the front of the hood though. Some of the aftermarket hoods come with a larger sized center vent as well. Anything that might help manage the heat is worthwhile in this car. Did you happen to try any of the gimmicks like removing the weatherstrip and/or shimming the rear of the hood? It doesn't make sense from an aerodynamics standpoint, but is free to try.
Hello, yes. If you read the thread, you would see that we did indeed V Mount the radiator, and transmission coolers. If you read further, you would know that we we have a high temp heat exchanger (oil) and low temp heat exchanger (blower) and stacking them we had enough delta in temperature between the two systems to stack them and see temps we wanted.
There is a lot to read and this gives you a bump anyway. Is the low temp hx for the blower on the drivers front or where is it?
I asked the same question in the other GSpeed thread, no need to answer in both places, pick one and I will find it...
Have you guys tried running 2 water pumps, at 2 different locations on the blower cooling fluid loop?
The advantage would be, a person could create a relay that basically keeps them both on 98% of the time, and the 2% or whatever time increment is needed, would be used to shut down one pump for 5 seconds... then it comes back on, and then 2 min later, the other pump shuts off for 5 sec, and they alternate back and forth, but 98% of the time, they are both on together.
What this would do is... use the FLOW from the other pump, to greatly accelerate the time needed to get the air away from the pump that is currently shut off. It might prevent cavitation all together as neither pump is having to work as hard.
2 props on the back of a boat will cavitate less at take off than 1 prop on the back of a boat. You are AT LEAST halving the cavitation's chances from occurring, but more realistically, probably even more... and then you are solving the cavitation in just a matter of seconds, instead of waiting for 3 minutes.
If you've already done that, my apologies, I read this thread a long time ago, know the gist of it.. but forgot if that was part of the solution or not.
for those of you using a top feed system or plan to in the future, where the aux tank is above the pump and if people are still experiencing cavitation with their systems in this orientation, i stumbled into a little tidbit of useful knowledge perhaps...
the zr1 2019 has the 2 pumps as listed below... and the pumps do not match part number with each other. The only thing I can see different about the 2 pumps is that the orientation of the 2 pumps is different in the GM parts diagrams.
I do NOT know how you guys are aligning your z06 pump's orientations with top feed systems, but IF the pump's orientation matters for them to have a long life, it looks as tho the pumps that are to be top fed are gm p# 13597902, and our cars come with 13597903 which is in side feed orientation. (it could be that orientation of the pump has nothing to do with the different part number, and if that is the case, then I would assume how long they shut down during cavitation, is different between the 2 pumps) 3 minutes is the shutdown on the 13597903 on our cars. Perhaps it is only 2 min on the pump ending in 02? I have no idea.
The zr1 has both of these pumps, and I believe they are oriented differently from each other in the zr1 (can someone confirm or deny this that they are oriented differently in the zr1?... one top feed one side feed) , as they are in the diagrams below (not the zr1 diagrams below, just gm parts diagram for each pump)
the 13597902 pump is used in the camaro zl1, and caddy's cars, but not z06.
it is possible that the 2 pumps behave differently as they experience cavitation... perhaps the 13597902 does not shut down for a full 3 min?
If anyone has this pump handy and can test it, let us know. But back to the orientation of the 2 pumps in the diagrams.... i can only imagine having the feed tube of the pump, pointing straight up to the aux tank that is feeding it, should likely eliminate cavitation much better, vs the side feed pump orientation would, as if there is ANY air in the top of the hose on the side feed pump, then that air will swirl around the impeller blade as they connect.
Long story short, top feed the 13597902 and your car might run better without any cavitation shutdowns and/or the shutdowns may be a shorter amount of time. I would think air would get away from an impeller blade where the face of the blade is facing up... instead of facing sideways.
Hello, yes. If you read the thread, you would see that we did indeed V Mount the radiator, and transmission coolers. If you read further, you would know that we we have a high temp heat exchanger (oil) and low temp heat exchanger (blower) and stacking them we had enough delta in temperature between the two systems to stack them and see temps we wanted.
Also, as for the hood removal, its a data point, and thats it. Was it right? We dont know. But it didnt work. We also removed the hood grill, and put a huge wicker in front of the opening to create a low pressure, in hopes of getting more air out.... but it didnt work either.
01-09-2017, 03:42 PM
