[ANSWERED] Changes to Engine Oil Cooling
08-11-2015, 10:48 PM
#21
I'm Batman..
Pro Mechanic
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Location: Lehigh Acres FL
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You're not going to get outright written commitment from anyone at GM for anything when it comes to future changes to a vehicle. Certainly not on a public forum like this. Tadge and others have said they're continuously exploring refinements to the car. A careful skill in "reading between the lines" should reveal to you that they're listening, and likely working on things.
Nothing will be engineered overnight. It's not how large automotive manufacturers work, specially when it comes to things as complicated as the power train of a car like the Vette. I know some people have said they want an OEM solution to this because those are generally, "engineered properly," and yet in the same breath continue to complain that a solution hasn't been provided yet. That's a fairly obvious contradiction in wants. It takes time to engineer things properly because unlike the aftermarket, the OEM has to make sure they do the usual 100K mile testing, etc, etc. And they have to make sure that whatever they do change doesn't have other bad consequences to the power train or other parts of the car.
If being an automotive engineer were easy, we'd all be doing it.
Nothing will be engineered overnight. It's not how large automotive manufacturers work, specially when it comes to things as complicated as the power train of a car like the Vette. I know some people have said they want an OEM solution to this because those are generally, "engineered properly," and yet in the same breath continue to complain that a solution hasn't been provided yet. That's a fairly obvious contradiction in wants. It takes time to engineer things properly because unlike the aftermarket, the OEM has to make sure they do the usual 100K mile testing, etc, etc. And they have to make sure that whatever they do change doesn't have other bad consequences to the power train or other parts of the car.
If being an automotive engineer were easy, we'd all be doing it.
People are spending heaps of cash on these cars and do not want to hear that the NEXT year model wont have XX issue, because the consumer was the guinea pig and GM figured out the issue after the fact. They don't want to find out that they were mislead with statements of track capability on a platform that outright CAN'T handle it. GM needs to step up on certain concerns and be public. The only way I see that happening is with a public statement. What better place to do it than right in front of the people that actually care about the issue at hand.
I am no stranger to reading between the lines, but that does not always mean something good. In my opinion I felt the response about the valve coking issue was GM tip toeing and basically saying "you wont have an issue -during your warranty period-". Right after they casually drop the warranty term drastically. Reading between the lines on that is pretty clear they know about the issue, and frankly it is what it is.
I know that all manufacturers are constantly looking for refinements to their models, but problems that are starting to become widespread (Z06 overheating) need an official acknowledgement and commitment for resolution. I do not own a Z06, and even I feel for the entire Z06 crowd on that one.
08-12-2015, 10:19 AM
#22
Personally I feel GM/Corvette should offer a Track Pak option, develop larger coolers/fans/radiators etc. and allow those who will be tracking their car often to select that option. They could offer lighter wheels, more track tuned suspension, areo, etc. Other automakers do it, this way you have an option for those who want to track their cars and for those who do not, they do not have to pay the extra $$$ for the upgrades. With the new Dodge Viper ACR looming, I think it will be a wise choice to offer such a package.
Just my two cents...
Just my two cents...
08-12-2015, 10:47 AM
#23
Pro
Right now we are seeing drops in oil pressure due to the thinning out of the oils at the near 300F temperatures. Thus, my "hope" would be that by installing the external oil cooler we could, at one end, get back some of the lost oil pressures while, at the other end, lose some pressure due to the added oil circuitry. If all goes well, the two effects would cancell and our oil pressures would remain at the present, slightly low levels. Now, GM could update the oil pumps but, who is really expecting that to happen...?
08-13-2015, 11:05 PM
#24
Instructor
My Z51 overheats on track, coolant temp and M7 transmission temp, and if I modify it, I risk losing the warranty, as the GM Brand quality manager who is looking after my case keeps asking via my service manager if I have modified the car every time it has to go in for warranty repair for the AFM actuator failure.
I do not drive the **** out of the car but I drive it fast and steady, and I only bought it because it had the track option Z51 package with the marketing of the most track capable Corvette ever. I expected GM to provide sufficient cooling for the job, and they did not. Not building myself a race car. Porsches, Vipers and my GT-R can run all day on track without overheating, and I've never ever had a car which constantly needs to go to the dealer for repairs after every track day, 5 times now for the same identical repair.
Different engineering objectives I assume.
It's not like Lou is the only one here on this forum who has had overheating issues on track with the C7. Just one example.
I do not drive the **** out of the car but I drive it fast and steady, and I only bought it because it had the track option Z51 package with the marketing of the most track capable Corvette ever. I expected GM to provide sufficient cooling for the job, and they did not. Not building myself a race car. Porsches, Vipers and my GT-R can run all day on track without overheating, and I've never ever had a car which constantly needs to go to the dealer for repairs after every track day, 5 times now for the same identical repair.
Different engineering objectives I assume.
It's not like Lou is the only one here on this forum who has had overheating issues on track with the C7. Just one example.
08-14-2015, 01:12 PM
#25
Pro
With the introduction of the C6 Z06 we had a chassis and tire package that allowed us to put much more power to the ground, compounded by an LS7 engine that loved to spin. Those elements drove us to add a much higher oil cooling capacity (roughly 16Kw) than an end-tank cooler could provide, so an air-to-oil cooler was selected as a ‘big hammer’ solution for the dry-sump motors, chosen for its ability to cool better at higher vehicle speeds. We made a conscious decision to go that route, as there are several downsides to air-to-oil coolers. They add airflow restriction, which reduces the effectiveness of the main radiator and impacts AC performance. There is unwanted oil-side restriction which takes some pressure potential from the main bearings. And as you mention, on cold days the oil will always be somewhat over-cooled. (Overcooling oil isn’t the worst thing, but it costs some fuel efficiency as colder oil has higher viscosity and more friction loss.) But for a car as track-oriented as the C6 Z06, this was the right trade-off to make, using a balanced take-off valve to bleed just enough oil to the cooler to satisfy cooling needs.
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tommyc6z06 (05-10-2020)
09-28-2015, 02:45 PM
#26
Safety Car
JVP, any chance a question like this would be acceptable to send to Tadge?
"Tadge, as a follow up to your response to question titled 'Changes to Engine Oil Cooling' received on 8/10/2015 I would like to ask the following. What is the difference in heat generation between older Corvettes and the C7 generation? In particular, what is the difference in heat generated in the C6 ZR1 compared to the C7 Z06? Is there a way to quantify the difference? I would like to be able to place in context your thorough response that quantified the heat rejection potential engineered in the Corvette platform. Since we know how much heat can be rejected, it would be useful to know how much heat is generated to place it in context.
Would it be correct to assume that the in-block direct injection fuel pump and the lower displacement TVS roots blower create additional heat in the block compared to the C6 generation? What are some of the other changes that generate more heat or reduce heat in the C7 powerplant or chassis in general?"
"Tadge, as a follow up to your response to question titled 'Changes to Engine Oil Cooling' received on 8/10/2015 I would like to ask the following. What is the difference in heat generation between older Corvettes and the C7 generation? In particular, what is the difference in heat generated in the C6 ZR1 compared to the C7 Z06? Is there a way to quantify the difference? I would like to be able to place in context your thorough response that quantified the heat rejection potential engineered in the Corvette platform. Since we know how much heat can be rejected, it would be useful to know how much heat is generated to place it in context.
Would it be correct to assume that the in-block direct injection fuel pump and the lower displacement TVS roots blower create additional heat in the block compared to the C6 generation? What are some of the other changes that generate more heat or reduce heat in the C7 powerplant or chassis in general?"
10-05-2015, 09:19 PM
#27
Drifting
You're not going to get outright written commitment from anyone at GM for anything when it comes to future changes to a vehicle. Certainly not on a public forum like this. Tadge and others have said they're continuously exploring refinements to the car. A careful skill in "reading between the lines" should reveal to you that they're listening, and likely working on things.
Nothing will be engineered overnight. It's not how large automotive manufacturers work, specially when it comes to things as complicated as the power train of a car like the Vette. I know some people have said they want an OEM solution to this because those are generally, "engineered properly," and yet in the same breath continue to complain that a solution hasn't been provided yet. That's a fairly obvious contradiction in wants. It takes time to engineer things properly because unlike the aftermarket, the OEM has to make sure they do the usual 100K mile testing, etc, etc. And they have to make sure that whatever they do change doesn't have other bad consequences to the power train or other parts of the car.
If being an automotive engineer were easy, we'd all be doing it.
Nothing will be engineered overnight. It's not how large automotive manufacturers work, specially when it comes to things as complicated as the power train of a car like the Vette. I know some people have said they want an OEM solution to this because those are generally, "engineered properly," and yet in the same breath continue to complain that a solution hasn't been provided yet. That's a fairly obvious contradiction in wants. It takes time to engineer things properly because unlike the aftermarket, the OEM has to make sure they do the usual 100K mile testing, etc, etc. And they have to make sure that whatever they do change doesn't have other bad consequences to the power train or other parts of the car.
If being an automotive engineer were easy, we'd all be doing it.