Looking at new exhaust system to otherwise stock 02 model. Do the "X pipes" offer better performance / better tone than the "H pipes?" I'm adding cat back exhaust anyway to a automatic roadster.

Also looking at adding cold air intake; any significant performance differences between systems.

Thanks,

Stroker...

 

An aftermarket X-pipe will tone down the popping sound you hear when you let off the throttle (with aftermarket catback systems). An H-pipe is what our C5s have from the factory, although the opening between the left and right side is very small, so you will hear plenty of popping. I kinda like the sound so I've left my H-pipe in place.

The biggest difference in intakes is CAI vs non-CAI. Here's a summary (prices may vary):

My costs may be a bit off, but most of what is stated here is based upon my experience with aftermarket intake systems for the C5....

If you live in California, think twice about the Vararam, as it can be a royal pain to install/uninstall/reinstall for smog tests. If you live in a state that doesn't have visual inspections, then also take a look at the following (grouped by cold air and non-cold air, but in no particular order) and my comments, if any:

Vararam: Brings cold air in through the fog light panel area to a panel-type filter. Owners have had good luck with system on the dragstrip, but plan on spending hours to install and a bit more to get everything lined up well. Downside: Eliminates engine bay-cooling air that would've come in from the fog light panels (Z06 or coupe/vert with opened-up panels), so the engine bay may end up being toastier, especially if you add headers later. $300-$400 (NOT smog legal in CA)

Vortech Rammer: Brings cold air up from in front of the radiator and into an enclosed box. Its filter is quite a bit smaller than the Halltech Warhead or Blackwing unit. $250 (NOT smog legal in CA)

Callaway Honker intake system: This one relocates the MAF so that it is just in front of the throttlebody. It directs cold air from underneath and costs about $500. I believe this unit is 50 states legal (smogwise) for non=Z06 C5s. Excellent design and quality. If cost is no object, this bad boy should be at the top of your list.

K&N FIPK: This is more of a semi-cold air system, as the cold air intake opening is more of a slit. Its filter endcaps are carbon fiber. However, it is configured similarly to the Halltech Stinger-R and is 50-states legal. $350

Reverse Zip-tie: Allows cold air to be drawn in from underneath, but the bare filter is exposed to potential damage from larger objects. The advantage here is that you may pass smog if the tech doesn't know "which way is up".

Warm air systems: (Easy installation)

Halltech Stinger-R: Not only contains the massive Warhead filter, but also includes a larger-than-stock airbridge and smooth throttlebody coupler. For $350.00 or less, this system represents one of the best bangs for the buck. Fortunately, if you don't like Z06 screens in front of cored-out fog light panels, (for about $40) you can add cold air induction. See my procedure at http://www.conceptualpolymer.com/corvette_c5_corner.htm
This is what I did and a swap to smog-legal status is very easy to do, as I have kept my Z06 intake box.

Halltech Stinger SSM: This intake system features an even larger filter than that of the Stinger-R, TRAP, and Blackwing. < $400

Blackwing: Includes just a large filter, but an excellent one at that. Its cost is close to that of the Stinger. Like the Stinger, it is not smog-legal in CA, but can easily be swapped.

Volant Twin Cone: This system gives you more open filter surface area than any stock box does and is well suited to an engine bay that gets cold air in from the fog light panels, as the filters are more or less in the air flow path. $265

2002+ Z06 airbox cover: A larger opening allows more air to be drawn in through the filter. Expect up to a 5 RWHP gain from this simple swap. $50

Zip-tie: An easy and inexpensive mod (eliminates the OEM box’s upper lid), but its sealing ability is questionable at best.


According to Jim Hall of Halltech, at 95-degrees IAT, the Blackwing (and other non-CAI intakes) will lose 1 degree of timing. At 135-degrees a full 12 degrees is pulled on the LS1 which equals 10 RWHP.

I measured before and after air intake temperature data with a stock Halltech Stinger and then with the same intake but with my CAI mod. The difference was staggering:

After sitting in traffic/slow-moving for 10 minutes or so, my stock Halltech setup was pulling in air that reached 145+ degreesF. Even after driving at highway speeds for 15 minutes, the intake temps never fell below 110F or so.

After installing my CAI mod, sitting in traffic/slow-moving for 10 minutes or more never produced more than 110 degrees F intake temps. After driving on the highway for less than a few minutes, the intake temps went all the way down to ambient temperatures (about 80 degrees F).

As far as horsepower gains, most aftermarket intakes will produce about the same horsepower gains if the intake air is kept relatively cool. During the many dyno runs I have seen, each car had its hood open and a large fan blowing air on the radiator. Vararam-equipped C5s produced the same gains as the Halltech and Blackwing-equipped C5s.

As was mentioned, the gains are only achieved permanently if the intake air is kept below a certain level. If not, much, if not all of your gains will be "dialed back" by the ECU.
Ebay specials: Most intake system air "runners" are made of plastic, not because it is the cheapest (it often isn't) material, but because the last thing most people want is the engine bay heat being transferred to the intake air via a metal runner. Many of the inexpensive Ebay intakes I've seen have metal runners - not good, IMO. Also, the filter is the most critical part of the intake system - why buy an unknown brand of filter for such a critical application? Please, don't cheap-out on an intake system. Stick with brands that have a long history of making quality products.

How good are these systems? My experience has shown that most will bump up RWHP by at least 10. The advantage of having cold air is that power will not be "dialed down" under slow moving/stop&go conditions.
You could easily lose 10 HP with a warm air system after engine bay temps rise during slow-moving conditions. Cold air prevents this from happening.

Dave

 

Dave,

Thanks for the comparisions on the options for better breathing systems. Good Stuff! I like your fresh air modification system..
I had two thoughts that I'm sure you can set me straight on using your modifications.
1) Does the engine see any increased temps due to a potential change of cooling air flow to the radiator? Living in Fla. heat is a concern!
2) Would it make a difference if the new filter were enclosed in a box... all of the cold air being forced into the filter and none bleeding into the engine bay

Stroker...