I'm looking to get as much performance out of this thing as possible. I've heard of people that have cut the radiator shroud underneath the blackwing but then have had problems with it surging and stuff. Any comments on that? Also, what about water ingestion? This car is my dad's daily driver so it sees rain fairly often and I was wondering what the chances are of him sucking water in it after hitting a big puddle. Thanks for the help yall. I plan on buying him the fog light inserts to get some more air in there for his birthday. Thanks for the help.

 

I'm about to replace my Vortech with a Blackwing because the Vortech is a bottom feeder (hole in the shroud). The Vortech filter picks up all kinds of road grime which I believe is reducing air flow. The Blackwing should be able to handle 500+ rwhp without cutting the shroud. I'd leave it alone.

 

Leave it alone. :iagree:

 

:withstupid:

 

The Corvette engine compartment is not like outer space... there is no vacumn when the hood is closed.

There is really no need to open up either the fog light area or the shroud to get more air to the Blackwing -- it'll breathe just fine -- just like you would if you were under the hood with it closed. Claustrophobia yes, suffocation, no.

Now, before the "cool air" crowd weighs, you will get some "cold air rules" benefit when the car is standing still or moving slowly. That is, cooler air, more performance.

But, since presumably your dad will want the performance when he is actually moving, and not standing in the drivway, I wouldn't sweat that either. By the time the car gets up to 25 mph, the air temperature outside and the air temperature at the Blackwing's location will be the same. That's why Chevy puts the filter where they do, before the radiator fans. It's the breeze thing, again, with all the existing openings, including the wheel wells and the bottom of the compartment. Since the filter isn't zip tied to the exhaust manifold, don't worry about the hot air either.

The best part about not cutting more holes, a lot of Corvette guys like to keep the engine clean as well. I bet so would your dad. You should see the engine compartment after a muddy rain with the fog light area and shroud open.

Cheers! :cheers:

 

I agree, leave well enough alone! If Donaldson found that it gave you more performance, they'd put it in their instructions guarantee'd. They would love to claim a higher HP gain and if they found cutting the shroud would allow that they'd be all over it. :)

 

It is physically located in front of the radiator and fans yes, but air flow wise most of the air entering the compatment comes through the radiator FIRST. There are no other openings (no Z06). Hence the comment by someone else in the thread that the engine compartment stays cleaner without holes cut in the front. That's because there is no direct air coming from the outside to the front compartment above the shroud. Might there be leakage around the wheel well inner fenders? Probably, but it is much less than the air coming through the radiator. People have measured the air temp in stock form and with just Z06 screens and it is cooler in the later configuration. I won't argue the more HP bit, it's a trade off with the greater dirt for me.

 

I had the donaldson without the cold air lid for about a year, than I cut the shroud and added the lid. I did this because I used autotap to see the cars air intake temp. From my experiences, the cold air lid makes a big difference in air intake temp, both sitting still and cruising around. I also did some of my tests at the drag strip and on about a 90+ degree day the car regeistered 140+ degrees while approaching the strip and went down to 115 degrees during the run. To me that was a bit hot. In back to back tests with a car with a vortex and mine without the cold air lid I was about 30 degrees hotter. When I installed the lid and tested again I was actually one degree cooler than the car with the vortex. Now...I since added a vararam and sold my donaldson and the lid. I bought into the hype about the vararam and hoped I would benefit from the change. To date the vararam got me .08 better in ET at the drag strip.......

 

So, in other words, your testing was inconclusive? Less than a tenth of a second for the really "cold air" from the Vararam?

From your post, it's not clear whether you cut the shroud or not when adding the "cold air lid." I assume you did. Did you ever run the test without a cut shroud?

There have been numerous other tests, years ago, that showed that the air temperature change was negligible once the car was moving (like about 10 degrees). As I posted earlier, the intake location isn't zip tied to the exhaust manifold, which is probably the hottest location in the engine compartment.

 

I guess I have to disagree with some of this. Apparently I am the first of the 'cold air' crowd. The stock air box is not in front of the fans - physically it is in the engine compartment and breaths that warmer air. While not claiming to be an expert here, I personally have experienced significant performance improvement by cutting the shroud and breathing cold air. Colder air will always provide better performance than warmer air. One can argue the inside and ouside temps may be approximately the same at sustained freeway speeds. However I believe that normal street driving including the track will result in significant temp differences. This is exactly why you will see all race cars set up for the colder outside air.

As far as water ingestion is concerned there is certainly some risk. I ran a Halltech for 2 yrs mounted below the shround on the front spoiler - about 6 inches off the ground. Never had any problem in heavy rain including freeway speeds. I believe the problem is most likely when slowly passing through a deep puddle. With the BW mounted above the shroud there is very low chance that enough water could get up that far in my opinion.

Just my opinion - go with what feels comfortable. :seeya

 

Leave the shroud alone. I lost an engine using a cold air bottom breather (see sig).

 

Daws C5:

Just so that some of the folks new to the C5 don't get confused.

Every C5 I've ever seen has the stock air box in front of the fans, which are behind the radiator. Is the there a separation? Yes, but clearly ahead of the radiator and the fans.

 

From my experience of having the Donaldson on two differrent C5s, I would not cut the shroud unless you plan on getting the cover for it. Without the cover I had surging on my 2000 FRC that went away as soon as I put the cover on.

 

This proves that cutting the shroud DOES make a difference. In fact, all of the highest-performance intake systems extract cold, outside air in one way or another. Even the K&N FIPK system requires that you cut the shroud to create a flap, allowing in cold air, but retaining a barrier for any water intrusion.

I'd also like to mention that Jim Hall has found a significant difference between his TRAP with Tunnel Port and the standard Blackwing (10 HP more for the trap).

 

I personally would not cut the shroud for any filter it it required leaving the area open to debris entering the engine compartment. The types that seal off the filter so only the filter is below the shroud are OK if you are careful with avoiding deep puddles.

That said, I do not agree that the temp of the air entering an above-shroud filter will be anywhere near the same as outside temps even on the freeway! If you look in there, the only way for air to enter a top-breather where the filter is on top of the shroud is to pull air out of the engine compartment and up over the radiator cross bar. In that case, the engine is serving as a huge heating core and it is actually quite efficient at heating air, even at the volumes being sucked by the intake! Even on the freeway, most of the hot air is going to be trapped up at the top: around the hood area, only to get sucked into your intake.

Mike

 

Others disagree.

Cold air does make a difference, cutting the shroud does not.

You do understand that difference?

And, Jim Hall sells his own system, just as other vendors do. They all claim their system makes more horsepower. Just like Jim used to claim it couldn't ingest water, and even offered "insurance." That claim is now dropped.

Take a vendor's claims with a grain of salt, particularly if he sells the product.

 

EHS - could you explaing what you mean by "Cold air does make a difference, cutting the shroud does not." Isn't the purpose of cutting the shroud to allow cold air flow into the filter?
:seeya

 

I'm sure he has, he would rather you buy his system than the Blackwing.

Asking about what's the best air intake and exhaust is like asking what's the best religion. :rant:

 

Actually, my results were very conclusive and When I put the cold air lid on I naturally cut a hole in the shroud. I added the vararam bit to show that the difference between the donaldson/lid is not that much diff than a vararam, although the vararam was a little better. I'm well versed in LS1Edit and autotap and my results were accurate...

 

Cold air gets to the filter whether the shroud is cut or not. See my first post above for a detailed explanation. What the shroud does keep out of the filter is water and dirt.