Combating the heat

[mike the snake]

My BRZ cooked the fans within a few minutes on the dyno. Heat is really REALLY an issue IMO. The thicker Robispec radiator moved the fans back into the exhaust and they died almost immediately.

I have decided to drop the Robispec radiator and have a Full Blown radiator coming. The Robispec just did not offer enough clearance between the fans and exhaust.

Full Blown has been awesome, and is helping me out with a revised downpipe that offers extra clearance, and their new shroud and Spal fans.

I also ordered up this crash bar http://www.enjukuracing.com/products...Scion-FRS.html

and I'm going to cut the "mouthpiece", either cut a row of holes, or cut it completely out and install my own grill. This will really open up the front and allow more airflow and better cooling.

With the stock crash bar, the intercooler (from any company) basically seals off the front opening, so the air that cools the radiator has to first flow through the intercooler.

Finally, I'm going to order up a vented hood. I want my car to be a daily driver and not worry about overheating.

[AVOturboworld]

Originally Posted by Dipstik-sportech

What about all the civics, talons, eclipses, etc that have a turbo mounted right behind the rad? None of them have overheating issues that I've ever heard of.

The Frozen North

The talons/eclipses, and of course, their big brother the Evo, were designed with turbocharging from the start. Mitsubishi designed the air flow through the radiator, and the radiator size, to reflect that fact.

That said, I spent a lot of time in stock cars (STI's, wrx's, legacies, evo's) in Japan overheating them at the track. It's absolutely not hard to do in a proper 30 minute lapping session at the track. And it's well known enough that any owner of said vehicles usually upgrades their cooling system, or takes it a bit easier at the track giving the car time to cool down.

Many, many vehicles will overheat when driven hard at the track for extended periods of time. You just don't hear about them because owners don't track them. When you go to the track these days, people are either driving an older car that was purpose-modified for track duty, or they are driving a higher-end car that has more track-readiness built in.

The BRZ/FR-S has an adequate cooling system, one that is just fine for the street, and will get overtaxed a bit on the track. I don't fault Subaru/Toyota for that, if they intended to build a track ready car, it would be more expensive, with sturdier suspension, brakes, oil and water cooling. I doubt few here would have paid 35k for a car that was slightly heavier, had worse mpg, and still only made 200hp.

Because it's designed down to the bare minimum weight and size, the cooling system does start dropping off in efficiency fast when the air flow through the radiator is impacted. Placing a front mount intercooler will naturally do this, the larger the intercooler, the more impact. If you remove the ducts on the side of the bumper opening to the radiator, that would also impact it as the air isn't forced through to the radiator directly anymore, it will bleed off to the sides inside the bumper instead. The more you place directly behind the radiator, the more impact it will have on air flow through it, as it needs to flow through the radiator and then down underneath the engine.

Venting the upper area, via the hood or side vents, will likely help when the car is stationary and running, such as sitting in traffic. I'm not sure it'll help when in motion, because that depends entirely on air flow through the engine. If the airflow continues to go underneath the engine still while in motion because the lowest pressure point is beneath and behind the motor, then the vents up above may end up being used to simply draw some air from above the engine downwards.

Getting airflow through the engine area is a science, literally, and will probably just be worked out in time through trial and error. From our track experience in Japan, we are concentrating on forcing the air through the front bumper and underneath, as that's returned the best results.

[shaunsweeney]

Exactly ducting and ventilation will be key in this application.

[mike the snake]

AVO thanks for the input.

I may hold off on ordering the vented hood. Actually, I planned to see how opening up the front by removing the crash bar and cutting the mouthpiece would work first before ordering the hood.


What about adding an upside-down "gurney strip" of rubber under the engine to help with pulling air out from under the engine?

[Dipstik-sportech]

Doesn't explain the civics and integras and they're engine bays are no less sealed than ours

The Frozen North

[AVOturboworld]

Different engine bay, different configuration, different radiator system, and when they say they take them to the track, do they mean the circuit, or the drag strip?

[Dipstik-sportech]

Doesn't matter track, strip or street. The turbo location is the same so why do those cars not run hot?

The Frozen North

[AVOturboworld]

It totally matters if you are running an engine full throttle for 30 minutes vs. 14 seconds when it comes to "running hot".

And I mentioned air flow through the engine several times for a reason - the air flow through a civic engine may be up and over the engine, instead of underneath. The engine, and engine bay, on a civic/integra is so totally different to a brz/fr-s that it's a case of comparing apples to oranges.

[Jesse@JDLAutodesign]

I've built a few fwd honda's and s2000's that ran at the track (time attack and HPDE events). Definitely takes some thought and/or $$$. We have plenty of good testing grounds here in the southwest

[Sellout]

I think the idea that the turbo being behind the radiator causes overheating is a bit overblown. Maybe that's what Dipstik-sportech is getting at.

When the car is moving there should be enough air coming through the radiator that the location of the hot parts isn't as big a deal as we might think. Sure it's going to have an effect, but I think generating twice the factory horsepower number will cause overheating whether your turbo is near the radiator or not, and it most certainly is possible to have enough airflow coming through the radiator that the cooling system can deal with having a turbo a few inches away. The airflow is our biggest problem, not necessarily the turbo.

For the record, the DSMs do actually need cooling mods to keep from overheating on the track. (or in traffic on a hot day) I can't speak about the Hondas because I've never had a turbo one...

The DSM guys (back when I had one and paid attention to such things) used hood vents behind the radiator to pull hot air up/out. There was plenty of other crap people tried but NOTHING works like a hood vent.

[shaunsweeney]

No one is saying turbo location is the only issue, but it is certainly a contributing factor. Heat soaking the radiator via the turbo hurts its efficiency.

Now place a bunch of stuff in front of that radiator as well, and you have overheating issues.

[Sellout]

Originally Posted by shaunsweeney

No one is saying turbo location is the only issue, but it is certainly a contributing factor. Heat soaking the radiator via the turbo hurts its efficiency.

Now place a bunch of stuff in front of that radiator as well, and you have overheating issues.

Just like nobody is saying it's not a contributing factor... jfc why do we have to go around in circles like this all the time

[Pete156]

Originally Posted by shaunsweeney

I disagree that talking about turbo placement should be off limits. It has everything to do with the topic. You can put the best cooling system in the world in the car, but a turbo being placed right behind it negates much of it. You have to think about heat in terms of the entire package when going turbo.

Location of turbo
Cooling capacity of radiator
Capacity of fans
Design of fan shroud
Placement of intercooler/other coolers
Air ducting and ventilation

If you don't have a complete plan, you will always be chasing the heat issue.

This is why I went with AVO. I think they have had a plan from the start for the heat issue.
Say what you want, call it cheap, call it Australian, whatever....
The turbo is in the right place. Right where the stock heat was. Under the motor, where the exhaust system was designed to be.
I agree with Paul @AVOturboworld.This car was designed with cooling air flowing under the engine, and appropriate panels to duct cool air in and hot air out. Makes perfect sense.
I have run my car hard with my AVO setup with NO overheating issue so far. No oil cooler, no special heat shields, no fancy vented hood or vented fenders, no special coolant. I'm not Ricky Bobby, but have yet to see my car get close to hot!
Front mounted turbos, with intake filters in the hot engine bay? Are you kidding me? There's your heat issue!
Just my $.02 worth.

[shaunsweeney]

I agree. I think AVO and PTuning nailed it in terms of turbo placement.