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Discussion Starter · #1 ·
The VR30DDTT as configured in the Infiniti Q50 and Q60 uses an air-to-water intercooler for charge cooling of the turbo output. The stock air-water system is pretty lousy (as told in 4 parts: Cool Under Pressure – Performance Heat Exchanger R&D, Part 1 – Stock Review).

Wonder if Nissan will improve the stock system for the new Z? Better yet, just give me a simple front air-to-air intercooler.
 

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The VR30DDTT as configured in the Infiniti Q50 and Q60 uses an air-to-water intercooler for charge cooling of the turbo output. The stock air-water system is pretty lousy (as told in 4 parts: Cool Under Pressure – Performance Heat Exchanger R&D, Part 1 – Stock Review).

Wonder if Nissan will improve the stock system for the new Z? Better yet, just give me a simple front air-to-air intercooler.
Welcome to the forum @Myax. With the way the front end is designed I hope Nissan can fit a nicely sized intercooler to deal with any issues and they fix any shortcomings from the Q50/Q60. I can't see them going to an air-to-air setup. Air to water offers the potential for the engine to be more responsive than air to air.
 

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Welcome to the forum @Myax. With the way the front end is designed I hope Nissan can fit a nicely sized intercooler to deal with any issues and they fix any shortcomings from the Q50/Q60. I can't see them going to an air-to-air setup. Air to water offers the potential for the engine to be more responsive than air to air.
I dont see changing to a FMIC on the VR30 for the Z. the dual intercoolers built into the turbo manifold area are kind of a distinct characteristic of that engine especially since the car makes 400hp in that configuration already. its already tried and true at that power level. I got a feeling this is a direct transplant of the VR30 into the Z as is.

will there be a need for a change in the aftermarket for builds or even something with the NISMO? who knows but I dont expect any surprises or reworks of the VR for this car at least at first
 

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Discussion Starter · #4 ·
This is a little concerning. Mishimoto, who I grant has a reason to see things their way (they want to sell you an upgraded intercooler), tested the stock unit and found it basically did nothing. Extremely ineffective at cooling the charge air both in instantaneous testing and longer duration heat-soak testing. Why did Nissan bother with the complexity of a air-water intercooler if it's no better than an air-air setup?

I'm also just not a fan, in general, of having a complex water system involved in the intake. What if one of the many cooling circuits in the intercooler develops a leak into the engine air path? Meh.

Really hoping someone comes up with a FMIC air-air solution.
 

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Did nothing, as in, didn't cool the air charge at all, or simply didn't outperform an air-to-air intercooler?
Is that a mathematical evaluation, or a physical trial?

Liquids are inherently more dense, and thus more capable of thermal transfer... so surface area becomes a factor.

Even if the liquid intercooler is designed to be only as effective as absolutely necessary, and doesn't outperform an air-to-air unit, in terms of thermal transfer capacity... it doesn't take into account several other factors.

Size - a liquid intercooler is likely a much smaller and more compact core because the liquid can transfer more thermal energy per square inch of core surface area than cooling air. An equivalent or better air-to-air would have to be a larger core with more transfer surface area.

Airflow - an air-to-air intercooler requires fresh airflow in and out, and an engine bay is not exactly an easy place for that to occur, especially without hood scoops, fender vents, or other more complex airflow management, and heat soak shielding.

If you move the intercooler core to an area with fresh airflow, such as the front grille, it creates more considerations.
-safety regulations for front impact
-increased costs for more parts
-packaging and routing around other components
-charge air volume between the turbocharger compressor and the intake valves and vacuum/pressure management.
-air metering for AFR over time.

A shorter intake tract, and less volume creates faster throttle and turbo response, more accurate metering, fewer parts, fewer joints and points of failure. It is easier to route smaller diameter liquid coolant piping with a pump, than ducting charge air, or fresh air around the engine bay.

The chances of a charge cooler leaking coolant into the intake tract are probably significantly lower than the risk of the radiator other fluid coolers rupturing and dumping their contents on the ground outside of the engine... those coolers are more subject to debris impact than a filtered air supply... and foreign object damage to the charge cooler(s) is likely to include bits of compressor debris from the turbos taking damage first.

Spontaneous component failure is a possibility... but there are thousands of component parts on a production car. "You spends yer money, and takes yer chances" with the whole system.

They also have to balance ultimate effectiveness against durability, warranty liability, packaging, federalization, fuel economy standards, subcontractor production, R&D, and the cost of the vehicle overall to produce and the customer's ability and willingness to pay the price.

Think of all the manufacturers that are producing turbocharged engines these days, and how many of them have liquid charge coolers, from F150 EcoBoost V6s to McLaren SpeedTail, and every price point in between, in volumes of tens of units of hypercars, to hundreds of thousands of mainstream vehicles.... the instances of failures en-masse are very low... and if so, are either warranty or recall covered for repair or preventative replacement.

Sure, the aftermarket may be more effective, they have less restrictions, and a customer base willing to spend a significant amount of money above and beyond the price of the car they bought.

Sure, Nissan may be able to do a bit more R&D to optimize the VR30DDTT incrementally and improve things a bit while they are working up the Z, and interested in making it well-received, effective, and reliable when it comes out.

They can also see what happens when costs increase, and Supra costs a significant amount more money, and is not selling like gangbusters.

Sometimes car companies make boneheaded choices to cut costs... other times they are making things possible that would otherwise not be feasible, and would otherwise not happen, or not succeed.
 

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Discussion Starter · #6 ·
I should have been more clear: Mishimoto's testing of the stock air-water system showed it struggled to bring down the charge air temp at all -- input and output temps were very similar to each other. In any case, there are plenty of companies offering air-air intercooled cars right here, right now. Air-water is a cop-out, a way to solve engine-bay packaging issues by throwing money at it. There's no way a separate cooling circuit with a separate pump (or two pumps, as in the Nissan Red Sport models) is less expensive than a simple air-air intercooler and some longer pipe.

Cars with air-air intercoolers:
  • Ford 2.3L ecoBoost I4 (Ranger, Bronco, Mustang, Focus)
  • Ford 2.7L ecoBoost V6 (F-150, Bronco)
  • Ford 3.5L ecoBoost V6 (F-150)
  • Every modern Subaru
That's a lot of cars on the road, and I'm sure there are many more models. Also, you're incorrect to state that the 3.5L ecoboost in the F-150 is air-water. Please cite your source, I could not find anything that suggested the stock form is air-water.
 

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I should have been more clear: Mishimoto's testing of the stock air-water system showed it struggled to bring down the charge air temp at all -- input and output temps were very similar to each other. In any case, there are plenty of companies offering air-air intercooled cars right here, right now. Air-water is a cop-out, a way to solve engine-bay packaging issues by throwing money at it. There's no way a separate cooling circuit with a separate pump (or two pumps, as in the Nissan Red Sport models) is less expensive than a simple air-air intercooler and some longer pipe.

Cars with air-air intercoolers:
  • Ford 2.3L ecoBoost I4 (Ranger, Bronco, Mustang, Focus)
  • Ford 2.7L ecoBoost V6 (F-150, Bronco)
  • Ford 3.5L ecoBoost V6 (F-150)
  • Every modern Subaru
That's a lot of cars on the road, and I'm sure there are many more models. Also, you're incorrect to state that the 3.5L ecoboost in the F-150 is air-water. Please cite your source, I could not find anything that suggested the stock form is air-water.
Interesting in light of Troublesome's exegesis that none of the cars cited (with the questionable exception of the 4-cyl Mustang) are performance vehicles that require a highly responsive engine - coincidence? I think not.
 

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I should have been more clear: Mishimoto's testing of the stock air-water system showed it struggled to bring down the charge air temp at all -- input and output temps were very similar to each other. In any case, there are plenty of companies offering air-air intercooled cars right here, right now. Air-water is a cop-out, a way to solve engine-bay packaging issues by throwing money at it. There's no way a separate cooling circuit with a separate pump (or two pumps, as in the Nissan Red Sport models) is less expensive than a simple air-air intercooler and some longer pipe.

Cars with air-air intercoolers:
  • Ford 2.3L ecoBoost I4 (Ranger, Bronco, Mustang, Focus)
  • Ford 2.7L ecoBoost V6 (F-150, Bronco)
  • Ford 3.5L ecoBoost V6 (F-150)
  • Every modern Subaru
That's a lot of cars on the road, and I'm sure there are many more models. Also, you're incorrect to state that the 3.5L ecoboost in the F-150 is air-water. Please cite your source, I could not find anything that suggested the stock form is air-water.
You may be right on the EcoBoost engines, it may be air-to-air... the truck has a big engine bay, and a big grille. But there are also many other cars out there with air-to-liquid intercoolers, as well, and they do that for reasons.

Did the Mishimoto test say how far above ambient the charge-air temperature was? a temperature delta in the charge air temperature is hard to generate if the delta between the coolant and the ambient air is not very large either.
Or the efficiency problem may be with the coolant radiator heat soaking, rather than the intercooler core thermal transfer efficiency...

I have owned a Subaru, and the turbo models either have hood scoops, under-hood ducting, or very long intake tracts if the turbos are low-mounted.. and prodigious amounts of lag. Maybe the new FA20 and FA24DIT engines in the WRX and Ascent are a bit better... but I would have to be convinced.

My former 05 Legacy 2.5GT with the EJ255 engine... the intake tube between the intercooler came apart and created problems on more than one occaision, and the piston rings started to wear and dump fuel into the crankcase, as well as the PCV system circulating oil, then fuel-mixed oil through the intake tract.

They are still using a variant of that engine 15+ years later on the Subaru WRX STI that is right in the same price bracket that the Z is in, and the Subaru is just as boy-racer as ever.
They refuse to turbocharge the BRZ or Crosstrek, and the turbo Legacy and Forester are lame.

My point wasn't that Air-to-Air is inferior, or that Air-to-water is always better... it is that there are all sorts of criteria and considerations as to why one or the other may be used, and some trade-offs in that decision-making.

I don't think anyone would dispute with the hope that things like intercooling, clutch slave cylinder configuration, and other details that could stand to be revised, should be updated if possible, for the new Z35 and Nissans' comeback from some rough years recently.

If the car is popular and sells relatively well, things like aftermarket upgrades will step up even further from there.

But if Nissan throws money at it, and then tries to recoup that with a higher MSRP... it is going to go the way of Supra, Alfa 4C, Lotus Evora, and others that are too expensive to be popular purchases.
 

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Instead of bickering about the intercooling here, go to an Infiniti forum and research this issue there. They've been at it for 5+ years.

Yes, the stock A2W system will heat soak.
Yes, there are solutions.
No, the solutions are not cheap.
 
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