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of my own experience and $. Well, after now having 6 exhausts on my NA since 1995 (most in the last 2 years after a frustrating search for the right one), I would like to offer a few observations. None of these observations (except my Borla) are really dyno-proven, but reflect lots of seat time and my personal experiences with them. Hopefully it will help someone make a better informed choice when this comes up in search. I should also preface this by saying that I use my Z as my DD, and don't really have time to spend at the track anymore. I do indeed value performance, and hence the intake, exhaust and ECU, but I also value streetable performance, and a sound that doesn't drive me nuts. Anyway, I'll describe them in chronological order of having them on the car: 1995: Stock (+ HKS intake). Good low-end power and pickup from stop light (for an NA), and very quiet (obviously). The intake added a little more noise from the motor, but still pretty quiet. Obviously had no idea what additional impact aftermarket would have yet. 1995: Greddy SP, Dual tip (not made that way anymore). 60mm piping, 65mm tips. I believe the design was mandrel-bent piping, st. thru resonators and packed straight through mufflers. This exhaust, combined with the intake seemed to really open up the motor at mid-high RPM, but I did notice a slight decrease on low-end power (again, the butt-dyno). Nothing significant, just noticed a slight difference in feel. In 2000 I added a JWT ECU and did notice some more pull above 4000 RPM. 2001: The Greddy SP rusted out, and here's where the saga and search really began. After talking to a couple of folks, and really wanting a stainless exhaust so I would never have to replace it again, I went with the Thermal R&D catback (2.5" mandrel-bent piping, 3" dual tips); it was nice looking, reasonably priced and stainless. Big mistake. The droning under load from 2-3K was simply unbearable, and the car really felt slow off the line - the RPM's would really dip at takeoff and required much more throttle tip-in to keep it from bogging down. True, above 3500 RPM the thing really performed, but I couldn't take the noise or the bogginess below 2500RPM, so I sold it for... 2002: ...the Borla (2.25" mandrel bent stainless piping, straight-through resonators and straight-through dual 3"/2.75" tip small mufflers). A decent improvement over the Thermal in terms of sound. Seemed to help the low-end situation a *bit*, and still made nice midrange power (dynoe'd at 197.5 RWHP too!) This was a fair bit quieter than the Thermal, but still retained some of the boominess between 2-3K. Many folks (probably those younger than I, with friends, family and others who don't care) would say this was not noisy, but at my stage in life and desire to attract a bit less attention, I still wanted quieter. 2003: After more searching, talking with some Z folks and thinking, I decided to try an experiment with a different set of mufflers on the existing piping. I ordered a set of baffled stainless "Superflo" mufflers from Stainless Technologies in Canada (304 stainless, 2.25" inlet, dual 3" tips) and had them welded on to my Borla pipes. As I understand it, both Genie and HKS use baffled mufflers to achieve better sound reduction, and this seemed like a logical approach to take. Well, I was wrong. In fact, they made no improvement noise-wise. It was still at a level which I couldn't accept, actually a bit closer to the Thermal! (again, many of you would probably like it). Fortunately, they still flowed really well, and the power felt the same, but I was quite disappointed (not to mention a bit peeved at the $ spent) that the sound was not reduced at all. This brings us to... 2003 (last week): I have given up on trying to build the perfect stainless exhaust and finally went with the HKS Sport R-2 (60mm mandrel bent piping, st. thru resonator, baffled *packed* muffler w/dual 65mm SS tips.) I can quite happily report that this is truly the best exhaust I have ever had on my NA. It is quiet @idle and under load (read: No Boominess at all!) and has a nice growl when you get on it to remind you that it's there. It also seems to have improved the low-end torque situation - no more dipping RPM's at takeoff, and tires seem to break lose with greater ease, like they used to w/stock (again, a subjective assessment, but there it is.) I wish to hell the HKS were stainless, but after all this experimenting, I'm happy to finally get the performance/sound part right. 2 out of 3 ain't bad! Anyway, what I draw from all this is that, for my NA and driving style, at least, the use of baffles/chambers combined with packing and the right pipe sizing has made all the difference in performance for me. Whether it's the additional backpressure needed at low RPM (or higher EGV, however you want to describe it), or the additional sound suppression provided by the packing, it seems to be just the right combination/compromise to make the NA perform well at most RPM's. (Again, I don't know if this would be the right combo for racing applications). Well, sorry to ramble. I hope someone can benefit from this info.
My Z at CarDomain (I know, but it's free) |
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