The VR30 uses A2W (air-to-water intercoolers). A2W intercoolers require the use of a heat exchanger(HX) and coolant to remove heat in the charge air created by the turbos. Hot air from the turbos is absorbed by the coolant in the intercoolers then "exchanged" or removed by the heat exchanger allowing colder coolant to be sent back to the intercoolers to absorb more heat. This is a continuous loop. The engine uses a radiator to remove engine heat the same way. They both use the same coolant but are completely separate systems with their own reservoirs. The smaller one on the passenger side is the one used by the A2W system. The stock HX on the VR30 is too small and is always my first recommended modification. This can be done with or without a tune and for both the 16+ Q50/Q60 and 23+Nissan Z.
When monitoring your charge air temps, the most important time to pay attention to temps is when in full boost. I get a lot of customers hitting me up worried that their charge air temps are sky high and its usually while sitting at a light or traveling at slow speeds. If there is no air/not enough air passing through the heat exchanger, the charge air temps will climb. This is known as heat soak.
As a tuner, I do not run the intercooler pump(s) at full speed at idle because it is not only pointless(if there is no air passing through to exchange heat) but it increases wear and tear on the coolant pump. If monitoring the water pump duty cycle, 80% is full speed. You will never see the coolant pump exceed this number.
As the rpms climb, you will see the water pump duty cycle quickly climb to full speed. This will happen well before the car makes full boost usually right off of idle. This also adds to rising temps at idle/low speed driving. You will notice that as soon as you go into full boost and get moving, the temps will quickly come down, settle, then slowly start to climb back up to their max temp by the end of the run. Typically, even on the smaller heat exchangers, I don't see temps above 20-30°f above ambient (usually closer to 20°f) unless it is VERY hot out and the system just can't keep up. If your temps are over 130°f-140°f by the end of a run and your HX is aftermarket, 999/1,000 you have a pump failure or there is air in the system. Otherwise, it just can't keep up due to excessive ambient heat. I see this a lot in the summer in places like Arizona.
It is imperative you have the heat exchanger installed by a professional. At least once a week, I get a new customer that has an improperly bled heat exchanger. In fact, this is the most common issue I see. I have had a few customers have to go back MULTIPLE times with one even using the same shop 5 times and on the 6th switched finally resolving the issue. Having this done incorrectly can cause excessively high cylinder temps which will increase risk of knock and lead to potential engine failure. Coupled with a P14AC code, you will see excessively high charge air temps while on the highway or during a full boost pull with sufficient air moving across the HX. On ECUTEK, if the HX temps exceed what the tuner deems safe, you will see the datalogging parameter "boost target multiplier"(BTM) quickly start to drop under 100% mid run. This parameter is used to determine how much of the tuners set boost target the ecu will allow based on a combination of engine coolant temperature, oil temperature, and charge air coolant temperature. If any of these 3 things are either too cold or too hot, the BTM will be less than 100%. 100% means the car is safe and ready to be raced/boosted. The BTM should only be under 100% while it is warming up to help prevent engine damage due to abusing it before it is up to operating temperature.
Lastly, it is common for the charge air coolant temp sensor to go bad. An easy way to figure this out(beside the P14AC code) is when logging charge air coolant temp, the temp NEVER changes and/or is very VERY far off from the charge air temps. If your charge air coolant says -40°f and your charge air temps are 130°f or if the sensor says 300°f and your charge air temps are normal, its a bad sensor. A bad charge air coolant temp sensor(with a properly working charge air system) will not cause any damage to the engine and is safe to be driven with.
Comments