Random Technology Cat-Back
Well, one of the most important performance modifications you can do to these cars is a Cat-Back (catalytic converter all the way back) exhaust system. Now for 98, it actually starts at the y-pipe, but catback is a more convieninet term. Anyways, looking at the available systems, I was a bit un-impressed with the selection. I wanted a high-flow system that would give me the best bang for the buck, and sound was a secondary concern. There are two main catagories of exhaust systems:
Stainless
Now right off, it's hard to justify $600 or more for an exhaust system, even if it will outlast the car. Borla is one such system. Even with it's HUGE following, it didn't impress me. Not to mention, EVERYONE has one. The B&B TriFlow is another stainless system. It has a great reputation and not many people have them. Well the B&B costs almost $100 more than the Borla, so that's out. SLP is another stainless system. But it only made 7hp on a dyno, so that is out as well. If I was only going to make 7hp from a catback, I damn sure wasn't going to spend $600 on it.
Aluminumized Steel
These systems are about 1/2 the price of the stainless systems, and offer a better bang for the buck, but will need to replaced in 2 to 4 years. The most popular system of this type is FlowMaster. These have a following to rival or exceed Borla. And these make some serious power as well. So this was my main consideration. Then someone told me about a system they saw by Random Technology. This system has not only a 3" intermediate pipe like the above systems, but it also has 3" exit pipes, which is something no other system I've seen yet, has. Now, exit pipe diameter isn't a major concern when it comes to back pressure. Dual 2.5" pipes will handle things fine, but I liked the idea of the dual 3" exits. Second, and most important to my deciion was the muffler. THe random technology system had what's called a Flow-Through muffler.
The Muffler
The PowerMax muffler, as it is called, is designed like none other that I have seen. It is designed so that it is a clear shot from the inlet pipe to the driver's side exit pipe. You can literally see right through the muffler:
In the center of the pipe inside the muffler is a 2 or 3 inch open section that allows exhaust gasses to exit through the passenger side. But, clearly, at WOT, the pressure of the exhaust gasses would force them right out the driver's side pipe as if it was a straight 3" pipe from y-pipe to tip. So this system, I'm sure flows better than an open-plate Borla. AND, bonus for you Stainless guys, this system is available in stainless as well!
Installation
Ok, I took the system to my delaership to install. Yes, I was gouged to the point where I'm embarassed to say how much I paid, BUT the whole system fits like factory and doesn't rattle or hit anything. I'm very happy with the job that was done and consider the money well-spent.
Well First we put the car up on the lift to remove the stock system:
If you look carefully, you'll see there are no clamps on that muffler. THe intermediate pipe had to be cut away from the muffler itself in order to remove the rear section.
Here is the stock intermediate pipe after it was cut fromt he muffler. Not too impressive. Down below I'll put this picture side by side with a pic of the 3" intermediate pipe. Anyways, after removing the muffler and tailpipe assembly, he had a tough time gettign the intermediate pipe off the y-pipe, even though it was clamped on. (picture of the clamp didn't come out)
I call this picture "Impending Doom". :) He didin't ahve to cut anything, he just used this to heat up the intermediate pipe where it was clamped to the y-pipe. Personally, I think he hauled this whole thing out just to scare me. ;) But after heating the end up he was able to remove the intermediate pipe without further cutting or difficulty.
Here's a pic of both systems. Yoou can see the vast difference in size between the stock and random tech mufflers and the stock and 3" tubing. This camera did a weird thing and made the Random Tech system look all shiny and nice. Truthfuly it wasn't so pretty. Also here you can see how the inlet and driver's side exit of the PowerMax muffler line up. Behind the Random Tech system you can see one of the tips still in it's plastic sleeve.
The new system had an intersting little item, a sleeve that fits over the end of the y-pipe. I'm not sure why the have this, but I wan't going to argue with their designers. ;) This has one very slightly tapered end which allowed us to tap the sleeve on with a hammer.
Here's the intermediate pipe on the car. The bigger tube is the pipe, the other one is the alum. driveshaft. This portion of the intermediate pipe (there's two sections to it, more later) had to be shortened by about 2 inches. They had the machine for shaping these pipes on -hand so the guy just knocked 2 inches off the end where it connects to the y-pipe and flared the end like it was origionally. Now, I'mnot saying all the random tech systems have this problem, just that mine did. So don't go lopping off 2 inches from the pipe without measuring first.
Here's the intermediate pipe where it connects to the muffler. I also put the pic of the stock pipe next to it so you can compare. Granted the shots are a bit different but I'm sure you can get a good idea for the size difference. The piece you see here was an angled piece that goes over the rear axle. The intermediate pipe was made in tow-pieces to make it easier to get it over the axle and through the suspension parts. After cutting the 2 inches off the forward pipe, this piece fit perfectly onto the mounting bracket for it.
Here, we put the new muffler on the intermediate pipe and supported it with a stand to test-fit everything. You can see the vast size difference between the stock and random mufflers (again, the funky camera angles, sorry).
Here's a rather poor pic of the custom hanger that was elded to the pipe. If you look carefully, yu can see where it was welded on, just slightly behind the hanger that was on came on the pipe. The hanger for the 93-97 cars I guess used a bracket of some sort. For 98, GM went back to a more traditional rod-type bracket that pushes through a rubber bushing. The guy happened to have one kicking around to use. He also welded the hanger to the bracket on the pipe as well to fore-silence any rattles that may have created.
Here's the passenger-side exit pipe. (yeah there's still a packing peanut in there) Looks huge. At this point he had already cut off the tips that came with the system. YOu can just see one to the right of the muffler-inlet in the second pic. Basically, they flared the ends of the exit-pipes like a trumpet and flattened them a bit to make them into ovals. They were incredibly ugly so I bought a pair of 3.5" Pacesetter Big Bore Monza tips without resonators to improve the looks of this system.
And here's the finished product. If you'll notice, everything is clamped together.. This was for ease of adjustment incase anything started hitting, as some systems do, and especially the tips, because if they rust out, I want to be able to replace them without replacing the whole catback.
Conclusion
So, waht did all this get me? Well, take a look for yourself:
Here's a dyno chart comparing the old system to the new
And for the sound, well here's for you to compare as well:
And some additional pictures of the tips are here.
