Water to air intercoolers (Page 1 of 2)

Have you looked into ways to remove hot air from the engine compartment. For example, on some cars you can remove the weather stripping by the base of the windshield and that helps get hot air out of the engine compartment.

If you are using headers or tubular exhaust manifolds, you might be able to wrap them to reduce under hood temperatures.

how is the space on the other side of the radiator/intercooler? could you switch from pullers to pushers and mount on the other side of the radiator?

We did tilt the radiator on the Saturn wagon. The eventual goal was to put a vent/bend down the metal over that area to help vent hot air. Picture it like a ramp that the air takes over the top of the hood after is passes through the radiator. Saturn's don't have heat problems and it is more related to stupid ideas like turbo charging it.

I've ditched the cat, which used to sit directly next to the radiator, and we're wrapped the down pipe. The turbo has a shockingly effective heat shield over it.

We have added a hood vent to try and get air out from behind the radiator. I THINK I can get the radiator to lean and open up more space for better ducting to this vent and also add better fans.

We have an aftermarket radiator that is like 60% thicker than the OEM in there, not much more we can do to that part.

I can try one of the aftermarket air to air that is not the full radiator footprint. It's been an internal debate between that and a water to air system.

Stock boost, maybe 1psi over. AFRs look fine. We have a tune on it because stock tune tried to be more fuel efficient which only hurt the overheating problem. New tune fixed that so now AFRs are mostly 11s to low12s if I'm recalling correctly. Getting it tuned further is on the table of options. It's never been on a dyno to get a good look at everything it's doing under load.

We do have a large oil cooler and I've replaced the OEM thermostat plate to get larger feed/return lines to the cooler.

Interesting group of replies that all address cooling in the same way.

How about this:
Air to Water Intercooler
Water to Air heat exchanger in the rear with blower fans and NACA ducts
in the rear quarter windows, or a roof mounted scoop.

The extra distance from front to back increases the volume of coolant.
The rear mount provides numerous possibilities for larger heat exchangers.
The removal of the front-mount and addition of rear-mount moves weight in the correct direction.

I dont think using a water to air is going to be better than an air to air thats why there are no responses.

Its going to add a bunch of weight, and more parts to fail for likely warmer IAT.         Air to air works, why solve a problem that doesnt exist.

Right. On paper water to air is better. The heat exchangers flow air better because you can have mismatched ports for the air vs water, water is great at heat dissipation/absorption. It's the heat soak variable I don't know about. An air to air setup can heat soak too. I wish I had collected more data in other races to know what our system was doing. Meaning if we're already seeing IATs that are high with the air to air, can the water to air be worse?

There is room. Right now I have a big fat oil cooler that is roughly 1/4 the height of the radiator sitting in front of both it and the intercooler, but there is space to fit that and a fatter shorter intercooler in that lower space. I don't think the battery box area gets much flow. We'd have to ditch the headlight to get anything.

I still think airflow is being dead ended in the engine bay. It comes through and just hits a wall that is the engine with nowhere to go. I haven't found a good way to improve that because there is so little space.

There is no doubt that an air to water is better at cooling but during an endurance race it wont be.     If you are putting a heat exchanger then why not just mount the air to air there instead.     

Think about it.  You would be using air to cool water to cool the intake temps.   Or just use air to cool the intake temps..............................................................................     An air to water is not for endurance racing.

The benefit is that with a water to air you can put the water to ambient heat exchanger anywhere and get it out of the air stream that's feeding the engine radiator. Since I'm having overheating issues that means less preheating to the radiator. I'm sure I can go calculate the required heat exchanger and water tank volume for a water to air system that won't heat soak. Is it more complicated, yes, but that's the trade off that's being weighed, is a more complex system worth it to help improve the other problem. My interest in a water to air system is less about the benefits to the charge air, and more to see if it can be a positive change to the radiator issue.

Won't be at Pitt unfortunately. We're spending April repairing the exploded transmission.

The fact is I don't know for sure where the problem is. I suspect it's a combination of several factors. The car has always had problems with overheating, but we've taken steps to make it better. It has a better radiator in it, one that's like 60% thicker. Can't go bigger footprint because there just isn't anymore space. I have the biggest fans I can fit in it. I want bigger. I'd rather have the OEM fans, but ours died a shaky death and replacements are crazy money. I've improved ducting as best I can, but suspect there is more I can do, and a ton I can do on extraction. It was partially tuning because stock tune targets fuel economy over sustained WOT safety, so a minor tune to change targets really made things a bunch better, but didn't 100% solve it.

I really think I'm just fighting the limitations of a cooling system designed for the street in a modern car. Because If I drive at like 6/10ths I'm fine, temps are great. It's just when I really hammer on the car lap after lap after lap it can't keep up. If it's raining at all we're sitting at thermostat temp all day long. The corvettes are the same thing, they are designed a street car first, they work on the street, but nothing is sized for sustained track use.

I probably need to get a couple temperature sensors into my cooling system so I can confirm exactly what is happening. Right now I'm just using the OEM sensor reporting through OBD. I need a sensor on the radiator inlet and outlet to confirm that there is or isn't a limitation there. Otherwise I'm just chasing my tail through guess and check.

Respectfully, I don't agree with a number of points.

Air to Air systems can heat soak. Subaru guys complain constantly while changing to front mounts. They can recover faster from heat soak yes, but they are not immune to the problem. As with all heat extraction systems it comes down to sizing for the application.

The heat exchanger for a water to air system does not need to be in the bumper. Sized right you can put it anywhere with the right fans and it will be fine.

Water to air is more complex, yes, but let's not pretend it's unreliable. It's a pump and fans, not a ton unreliable there. It's heavier, yes, but if I cared about weight I wouldn't have raced with the huge NAV headunit and full stereo installed, or I would have gone through and cut out all the stupid extra brackets still in the car.

I am not trying to argue that water to air is better in every way, I'm simply weighing it's cons against ways it could help improve the radiator performance.

Let me fully lay out the current setup again, because on paper it should not be bad. The ducting is not perfect, but it's pretty damn good. The bottom of the bumper is sealed to the bottom of the radiator. I have vertical plates cut to match the bumper cavity so air coming though the front openings is directed all the way to the radiator, it cannot escape to the sides. These plates also cover the small gap between the intercooler and radiator. I even have a plate along the top of the air path to make fully sure there is only one sealed path from bumper openings to radiator. Pictures from 2018 when I first did the work. I've improved things after we replaced the oil cooler with a larger one.
https://photos.app.goo.gl/mUA8oqMX6WrLjZBc8

My fans are just ok. They are two 1300CFM spal 12" fans chosen because they were some of the highest flowing fans for the depth requirements we have.  I physically cannot fit a taller fan before they start hitting the turbo (see photo in that album). While I have the car apart to replace the exploded transmission I am going to see if I can modify how they are mounted to lean them more and make more room for fans. I would love to put a stronger fan or two in there, but it requires making space.

We have one hood vent now to try and get hot air out from behind the radiator. There is no direct ducting up to it because the space is so small. If I can lean the radiator I will make a better effort to duct this.

Cat is gone, down pipe is wrapped, turbo has a heat shield that works really well, so I've done most all I can do to limit the engine bay heating the radiator. Car has a tune to specifically address fuel maps and make targets safer. This single item made the largest change of anything we've done. Car went from overheating in 1 lap, to over heating after 30 minutes. Wide band (and fuel consumption) confirms we are in good target regions.

I will also point out that I am the only driver able to overheat the car unless it's a very hot day, then others can. This indicates that there is something about my driving that is making the issue worse. My brother turns similar lap times to me, but claims he never sees temps over ~212. I can get them over 220 if I don't back off. I've never tested to see how high they'll actually go. We are lining up better data logging to compare exactly how I'm driving differently, but I'd like to have a cooling setup that is driver immune.

In short, I'm just plain out of ideas. I can keep iterating on ducting over and over, but I've been doing that for years and the problem persists. I'm kinda tired of spending my stint getting to go 2 laps full speed 5 laps 3/4 speed.

Try the air to water, its not widely used in road racing for a reason.     High water temps is a common issue with road race cars, we are still fighting it with a massive griffin radiator and we have no turbo.     The turbo/intercooler are not your problems.

It does sound like you've done your due diligence on trying to keep air going through the radiator!

Pity you couldn't push the radiator forward a few inches to allow for better flow -

--> As a question for the group, above what car speed do fans start making significantly less total air flow?  Surely the fans aren't impeding air flow, but would putting them on the front of the radiator in this tightly-packed area actually improve airflow 10 or 20%?

--> Also, does anyone know how to tell when a water pump is being overdriven?  I'd think that water pressure would rise linearly with engine speed, and if not, then the pump is either cavitating or 'stalling' as water bleeds around the edges of the impeller.  Would throwing a pressure gauge on the water pump output and checking across the RPM range give us any useful info in the garage?

Interested in the result since it's always hard to tell whether overheating is due to not enough air flow or not enough water flow, and since we're lazy and don't have time to test it's almost always bench engineering until it goes ---boom---.

To be clear, I do not think the intercooler is THE problem. I'm wondering if changing it can be a variable in solving the problem. That's all. Changing up the intercooler setup may aid in improving the airflow through the radiator.