Jul 11, 2019 update to the Chevrolet Corvette Z06 project car

Project Z06: Breathe Freely with Breathless

The stock intake snorkel on a C5 Corvette is a little weird. An “air bridge” hops over the radiator and connects to the air filter assembly nestled in the nose of the car. It all seems to make sense from a layout perspective, until you consider where the air actually comes from. Although the intake sits right behind the front bumper, there’s no path for fresh air to get through that bumper to the engine. The intake draws all its air from under the sealed hood, which is heated by the LS6 engine.

Luckily, Breathless Performance has a simple solution. Essentially their system flips the intake over and draws fresh air from below the car, where it’s being forced into the radiator inlet anyway.

The installation requires some cutting of the plastic shroud that separates the radiator inlet area from the engine compartment, but the shroud is soft and easily cuts with a good razor. Actually, don’t use a rotary or reciprocating device. The plastic is so thin and soft it will melt and gum up and make a huge mess. Just put a sharp blade in your knife and you’re good to go.

Breathless sends you a template to make the cut, and it’s perfectly easy to do with the shroud still in the car if you remove the hood, which is also fairly simple. Actually, removing the hood is almost easier than removing the shroud, so that’s the path we recommend.

Once installed, the engine has a supply of fresh, ambient temperature air to draw from, and we saw an instant difference in our intake air temps. On a dyne, being fed only by a fan, we saw drops of at least 10 and as much as 15 degrees during our runs. We also saw gains of 4-5hp at the wheels, particularly in the midrange from around 3200-5500 rpm. And, again, this was on a stationary dyno.

At speed, where the intake is allowed to gulp even more fresh outside air, we expect even more performance gains and reduced intake charges. We’re looking forward to running some tests at speed on a closed course.

To finish off our install we wrapped the Breathless-supplied air bridge with some reflective tape to keep whatever radiator heat out of the intake tract that we could.

Now, the big fear with this intake will be water ingestion. We now have an open path from the underside of the car through the one filter inside the airbox to the engine. It’s a reasonable fear, but we’re comforted by two data points: First is that the actual opening is quite high, and especially when paired with a chin spoiler, quite separated from a direct view of the ground. Second is that Breathless reports they have never experienced any water ingestion with the system in their testing or with use among customers. Basically, to create a water ingestion situation, you’d have to do something very, very dumb. We recommend not doing that, and enjoying the additional power and lower intake temps that the system provides.

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Comments
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deaconblue
deaconblue New Reader
7/11/19 1:48 p.m.

Looks like the Breathless system is very similar to the Callaway Honker system on my C5 and possibly less expensive as well.

BTW, did you guys ever install the oil cooler setup from Improved Racing that you mention during the video about installing their oil pan baffles?

Harvey
Harvey SuperDork
7/11/19 1:56 p.m.

Interesting. The C6 Z06 intake gets outside air from the front scoop.

JG Pasterjak
JG Pasterjak Production/Art Director
7/11/19 3:01 p.m.
deaconblue said:

Looks like the Breathless system is very similar to the Callaway Honker system on my C5 and possibly less expensive as well.

BTW, did you guys ever install the oil cooler setup from Improved Racing that you mention during the video about installing their oil pan baffles?

Yeah, similar principle in that they both breach the shroud and get cool air from outside the engine compartment. 

We took the car over to Orlando and Improved prototyped up some brackets and was exploring some various mounting options for a one-box C5 kit. We need to make one more trip over there and drop of the car or final prototyping and fittment.

deaconblue
deaconblue New Reader
7/12/19 8:05 a.m.

In reply to Harvey :

C5 is a bottom feeder, while the C6 & C7 are both front feeders.

deaconblue
deaconblue New Reader
7/12/19 8:07 a.m.

In reply to JG Pasterjak :

Way cool (sorry for the pun)!  Please keep us posted on how that turns out.  I am looking forward to ordering their C5 kit once its available along with those oil pan trap door baffles.

JG Pasterjak
JG Pasterjak Production/Art Director
7/12/19 10:32 a.m.
deaconblue said:

In reply to Harvey :

C5 is a bottom feeder, while the C6 & C7 are both front feeders.

C5 is a bottom feeder for the radiator, but the stock intake is all contained under the hood. It's more of a "behind the bumper but in front of the engine" feeder for intake air.

Floating Doc
Floating Doc SuperDork
7/12/19 10:44 a.m.

I'm glad you address the potential for water intrusion, as the potential for hydrolock seems significant. 

 Running one of those in Volusia County is going to test that.

Keith Tanner
Keith Tanner MegaDork
7/12/19 10:47 a.m.

You'd have to be in water about 2' deep for hydrolock to become a possibility. It's easier to suck air than water, so that's what the engine will do until it has no other choice.

JG Pasterjak
JG Pasterjak Production/Art Director
7/12/19 11:37 a.m.
Keith Tanner said:

You'd have to be in water about 2' deep for hydrolock to become a possibility. It's easier to suck air than water, so that's what the engine will do until it has no other choice.

Yeah, this.

While technically the chance is greater with this system than with the stock setup, if you get into a situation where hydrolock is a strong possibility, there's every chance that the engine is the least of your problems at that point.

jstein77
jstein77 UberDork
7/12/19 12:18 p.m.

What about the reduction in air volume through the radiator?  Have you noted any change in water temperatures?

NorseDave
NorseDave Reader
7/12/19 1:39 p.m.

I guess I've never really looked specifically at this before, but is the stock C5 radiator actually mounted in a reclined position, ie, btm is farther forward than top, rather than vertical?  I don't recall ever seeing that.  

JG Pasterjak
JG Pasterjak Production/Art Director
7/12/19 3:58 p.m.
jstein77 said:

What about the reduction in air volume through the radiator?  Have you noted any change in water temperatures?

There's no blockage of the radiator. The intake basically just shares the same cavity as the radiator intake. There's still more than enough volume to feed both properly.

JG Pasterjak
JG Pasterjak Production/Art Director
7/12/19 4:00 p.m.
NorseDave said:

I guess I've never really looked specifically at this before, but is the stock C5 radiator actually mounted in a reclined position, ie, btm is farther forward than top, rather than vertical?  I don't recall ever seeing that.  

Yeah it's leaned back at a good 10-15 degrees. The hot setup is to actually lean it back even more and duct air through i then out the hood. Hard to do that and keep a/c, though, since the condenser sits right in front of the rad.

 

Floating Doc
Floating Doc SuperDork
7/12/19 6:33 p.m.
JG Pasterjak said:
Keith Tanner said:

You'd have to be in water about 2' deep for hydrolock to become a possibility. It's easier to suck air than water, so that's what the engine will do until it has no other choice.

Yeah, this.

While technically the chance is greater with this system than with the stock setup, if you get into a situation where hydrolock is a strong possibility, there's every chance that the engine is the least of your problems at that point.

Today I learned...

Thanks for clarifying.

NorseDave
NorseDave Reader
7/12/19 6:55 p.m.
JG Pasterjak said:
NorseDave said:

I guess I've never really looked specifically at this before, but is the stock C5 radiator actually mounted in a reclined position, ie, btm is farther forward than top, rather than vertical?  I don't recall ever seeing that.  

Yeah it's leaned back at a good 10-15 degrees. The hot setup is to actually lean it back even more and duct air through i then out the hood. Hard to do that and keep a/c, though, since the condenser sits right in front of the rad.

 

Interesting.  Those setups are usually leaned forward, aren't they?  Like this one (from a thread on here):

 

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