EGbeater

I've purchased and installed a Forcewerkz 70mm single exit "Track Edition" exhaust on my '03 AP1. I purchased it from Union Performance, a vendor/sponsor here on s2ki.com.

In this thread, I'll present information about how it fits, how it sounds, and how much it weighs.

CLIFF NOTES CONCLUSIONS

For those who would like to know how the story ends before reading the whole novel, here is how I grade the Forcewerkz exhaust:

Overall build quality/materials: C (I did initially give it an "A" rating, until a weld inside the muffler canister broke after about five months and six outings at the track (five of which where two-day events), which constitutes about 700 miles on-track, and also about 2200 miles of street driving in that time).
Sound quality/lack of drone: A
Fitment (clearance under-car): C+
Fitment (exhaust tip, AP1 bumper): B
Power output: A-
Weight reduction: B+
Value for the dollar (@ $550 shipped): C- (initially, I rated value as an "A" until the weld failure inside the muffler)

Extra credit: made in the United States

Important notes: The under-car fitment is potentially a D if you're using axle spacers (more info below). I would give the Forcewerkz exhaust an A+ for sound quality/lack of drone, except I don't think that's fair when I haven't owned other exhaust systems on the S2000. If/when the price of this exhaust goes back up to $750 shipped (what it's currently listed for on Forcewerkz' website: http://www.forcewerkz.com/honda-s200...xhaust-system/) I'd give it a value grade of B-.

OVERALL SPECIFICATIONS / BUILD QUALITY

EDIT: 7/21/2014: After five months and six outings at the track (five of which where two-day race events), which constitutes about 700 miles on-track, and also about 3500 miles of street driving in that time, a weld inside the muffler canister has broken. The muffler/tip section of the exhaust now has some side-to-side play, and the exhaust rattles/clatters at idle. The weld that is broken is fully INSIDE the muffler canister, so I can't provide pictures of the failed joint, nor can I easily have it repaired (the muffler canister will have to be partially cut off in order to gain access to the area that needs to be fixed).

I've emailed Forcewerkz at sales@forcewerkz.com twice (http://www.forcewerkz.com/contact-us/ where it says, "All questions will be replied to within 24 hours," har har) and received no reply (over the course of two weeks) so it's obvious that Forcewerkz has no intention of honoring the "lifetime warranty" that was stated when I bought the exhaust. Also, the 70mm single exit S2000 exhaust has now been removed from the Forcewerkz website, so clearly they're not selling it anymore.

While I am still using the Forcewerkz exhaust on my S2000, and it serves my purpose of being a track car just fine (even with the muffler's internal weld being broken), at this point I do not recommend anyone buy this exhaust, unless you can get it dirt cheap—your call on what you think an exhaust with no manufacturer support and a design that has been shown to fail after some admittedly hard track use is worth, but I'd say under $400 new and maybe $250 to $300 used.

The overall build quality and materials used in the Forcewerkz exhaust I received looks excellent, with the single exception of the mounting tab of the additional exhaust hanger that goes to one of the OEM bolts for the driver's side rear diff mount (more details on that later). Everything else displays consistent, even welding beads and is nicely polished and very shiny (if you're into that kind of thing).

The Forcewerkz exhaust system is shipped in two separate boxes, and while the packaging for the front section wasn't great (the end flange was poking partially out of the box when I got it) no significant damage occurred. The manufacturer could stand to do a better job of packaging the exhaust components to keep them from trying to get out of the boxes in transit though... all it would take is inserting a couple pieces of cardboard inside the box to make it double-wall in a couple critical places.

The total weight of the system (including center gasket and hardware) is 28.83 pounds. The silencer and silencer mounting bolts add almost exactly half a pound.

Front pipe section: 13.92 lb
Rear muffler/tip section (without silencer): 14.28 lb
Center two-bolt gasket & bolts/nuts: 0.19 lb
Additional hanger (to driver's side rear diff mount): .44 lb
Silencer insert w mounting bolts/nuts: 0.49 lb

Forcewerkz 70mm single outlet catback exhaust, total weight (w/o silencer, not including re-used OEM rubber hangers): 28.83 lb

For the purposes of comparison, I also weighed my OEM dual-exit AP1 exhaust system... not including any of the OEM rubber hangers, it weighs 49.38 pounds—basically confirming the weight of 50 lbs quoted here: https://www.s2ki.com/s2000/topic/331...haust-weights/

I was hoping it weighed closer to the 55 to 58-pound weights I've seen claimed online. The rubber hangers are 0.22 lbs each, so even including all five of them, the OEM AP1 S2k catback exhaust is still a hair under 50 1/2 lbs.

In the two pictures below, the exhaust has one rubber hanger left on it, which is why it's reading 49.6 pounds as opposed to the 49.38 I stated above:





Both the resonator and the muffler of the Forcewerkz catback are of the straight-through, perforated-pipe design (best for maximum flow, obviously not the best for noise reduction).

The piping material is indeed 70mm OD as claimed, with an ID of approximately 67mm. The internal diameter of the tip is about 86 mm or 3 3/8"—relatively small. The size of an exhaust system's tip/s will affect the overall sound quality slightly; a larger tip tends to make for louder or dronier exhaust.

The overall length of the silencer is 7", and the ID of the silencer tube is only 36mm (1 13/32") so obviously using it will really cut down on airflow/peak HP, but I don't really care how much power it chokes off, since I will just be using it while driving to and from race events.

The nuts and bolts supplied to secure the silencer tip are stainless steel instead of rust-prone hardware; a nice touch. Some stainless steel spring washers would have been nice to prevent the hardware from vibrating loose and then disappearing though (a little Loctite would work too). I opted to replace the nuts supplied by Forcewerkz with some stainless steel nuts from McMaster-Carr with plastic inserts... I'll find out if the heat becomes a problem or not.

Pics of the exhaust system before installation:

EGbeater

UNDER-CAR FITMENT

IMPORTANT NOTE: At this time, I've installed the Forcewerkz catback exhaust with the OEM cat and the OEM header, so the fitment information immediately below is specific to retaining the rest of the factory exhaust system. Obviously, since I have an AP1, information I've provided about how the exhaust tip fits in my bumper cover is specific to the AP1 bumper cover.

It took me about 3 1/2 hours to install this exhaust. This including putting the car up on four jackstands (I did it in my garage) and at least half an hour at the end tweaking the fitment. Taking pictures throughout the process adds time too.

Hand tools needed are pretty simple: in my case, since my car's exhaust system was 100% stock, I needed some PB Blaster and a 1/2" impact to break loose the three 14mm nuts that secure the OEM catback to the OEM cat. I used a old pump-style hair spray bottle filled with water to lubricate the rubber hangers and make them easier to remove (I used water instead of lubricant to make sure it didn't degrade the rubber), and I used a Harbor Freight pry bar on the rubber hangers to help slip them off.

Another very convenient "tool" to have is a cardboard box that is the right height to support the front section of the Forcewerkz exhaust piping while you're getting the rubber hanger back in place. The box or block of wood is pretty critical if you're doing this job by yourself, like I did. The cardboard box is also handy for holding up the front section of the OEM exhaust, after you've pulled the three nuts to the cat, and while you're dicking with removing those rubber hangers above the mufflers.

I installed the front section of the Forcewerkz exhaust first. It was fairly annoying to get the rubber hanger that supports the rear of the piping hooked back up, but after a few minutes of trying (and swearing) I got it. I didn't bother to replace the OEM gasket between the cat and the catback with the new gasket Forcewerkz supplies with the exhaust system because the old gasket looked fine and I was in a hurry/being lazy.

Others with this Forcewerkz exhaust have stated in this thread (https://www.s2ki.com/s2000/topic/106...4/page__st__25) that exhaust's resonator (first muffler) doesn't clear the factory brace that goes between the lower suspension points. On my car, the clearance from the back of the exhaust's resonator case to the subframe brace was very very tight (about half a millimeter) so I spaced it out by using a couple washers between the brace and the unibody (at each of the two 14mm-headed bolts for brace on the passenger side). Now there's about 4mm of clearance and no issues with rubbing or noise from that area.

I do agree with what klch said here: https://www.s2ki.com/s2000/topic/106...t__p__22991791 –that the manufacturer could easily solve this issue by positioning the resonator 1" farther forward—they should do this with all of the S2k exhausts they build going forward.

Here is the front section bolted up/hung by the rubber hanger, with the OEM cross brace still removed:



From the front, with the brace reinstalled, no washers:



View from the rear:



The washers I used to give a bit more clearance:





I know it's hard to tell, but there's about 3/16" of clearance between the top of the brace and the resonator can with the washers installed:





If I weren't using my S2000 for autocross competition in STR class, I probably wouldn't have even reinstalled the factory lower brace, but it's not class-legal to remove it in STR. I'm sure the OEM lower cross brace does do SOMETHING to stiffen the rear suspension pickup points laterally, a tiny bit, but I doubt that most drivers (even experienced autocrossers or track drivers) would be able to tell if the bar was missing or not in blind tests. In my experience in autocrossing and driving on road courses in many different vehicles, I will tell you that 95% of making a car handle well and grip hard has to do with tires, alignment, suspension (specifically, the quality of the dampers and the spring rates), wheel width, swaybars, and driver skill of course—NOT how "stiff" the chassis is.

In other words, unless you're a racer who needs the car to retain the brace for compliance with your class rules, if you end up not being able to re-install the OEM lower brace with an aftermarket exhaust, it's really, really not a big deal.

What is a much more important fitment issue is the clearance of the Forcewerkz piping after the resonator to the passenger side rear axle. This is not simply a "it'll make an annoying rattling noise if it hits" problem; it's a "it could potentially damage the exhaust to where it needs repair" problem.

Here's a pic to show where the potential issue is (circled):



The amount of clearance from the heads of the axle bolts is about 1/4", which would be plenty if the exhaust didn't move at all. With the rubber hangers, 1/4" of left to right movement is certainly possible.

This motivated me to try to increase the clearance at this key point, and to make sure to limit how far the exhaust can swing to the left with the additional hanger. But the more you push the exhaust system to the right (towards the passenger side, away from the axle), the more off-center the exhaust tip will be in the bumper cover opening. I also tried to get the exhaust tip to center by adjusting how the rear section of the exhaust bolts to the front section, but that didn't resolve the problem. I ended up with the exhaust tip slightly to the right in order to maximize clearance between the exhaust piping and the whirling bolts of the axle.

During normal street driving, there was no contact between the axle bolts and the exhaust. At the autocross event this weekend though, during my first run, I heard an abnormal noise while cornering, and afterwards confirmed that the axle bolts had contacted the exhaust. It made a scraped, ovalized dent that's about 1/8" deep. Certainly not enough to significantly hurt exhaust flow, and it didn't go through the exhaust piping's wall either. On the subsequent three runs, I didn't hear the noise again, so it either didn't contact anymore because the piping has been sufficiently dented, or it only rubbed slightly and very briefly so I couldn't hear it through my helmet.





I can't say definitively at this point if this will become a problem later on, if contact continues to happen, but I'm not concerned about it. Steel (even stainless steel) is fairly resilient; if it were a titanium exhaust, I'd be more worried. I still may remove the exhaust and go at it carefully with a ball peen hammer to enlarge and deepen the dented area slightly to prevent further contact.

IMPORTANT NOTE: if you're running axle spacers to minimize CV joint wear because your S2000 is really low, I think the spacers will make this clearance problem much worse—something to consider if you're running aftermarket axle spacers.

By the way, the edge of the resonator canister is pretty close to a bolt head under the car as well, but since that part doesn't rotate, isn't not a big deal (and there's no sign that it hit it at all after the autocross event yesterday):



About the additional support/hanger that goes from the 14mm head bolt at the 5 o'clock position of the driver's side rear diff mount to support the end of the front exhaust section: it's an ugly, roughly welded part. The round hanger wire is the same stainless steel material used on the exhaust itself, but the flat bracket it's welded to is just mild steel (you can see in my picture below that a refrigerator magnet sticks to it), and the welding is muffler-shop quality. I decided to paint the non-stainless portion of this part flat black to keep it from rusting:







I also swapped out the OEM diff bolt that this bracket goes to (at least I think that's where it's supposed to go to; I couldn't figure out how else it would fit the car) with one I had laying around that's 3mm longer than the OEM bolt to make sure there's enough thread engagement... I'm sure it would be fine to just re-use the OEM bolt. I used some Loctite blue on the bolt threads to make sure it doesn't vibrate loose and eject itself sometime down the road (literally).



Here you can see the bracket installed, and how I chose to adjust in the slotted end in order to push the exhaust to the right (passenger side). I also put a hose clamp around the OEM rubber hanger to minimize how much the exhaust/muffler can move back and forth. This is also probably unnecessary.



Lastly, there is no issues with clearance between the AP1 bumper cover and the muffler can and Helmholtz resonator pipe... close, but no problem:



SOME THINGS TO CONSIDER ABOUT AFTERMARKET EXHAUST FITMENT

I have installed several other aftermarket exhaust systems before (on other cars, not the S2000) and in my experience slight issues with fitment and clearance are certainly not unusual.

Yes; ideally, the exhaust should fit absolutely perfectly with no issues with clearance or how the exhaust tip lines up in the bumper cover's opening. However, keep in mind that when you upsize the OEM piping diameter of the factory AP1 exhaust from 60mm/49mm OD (60mm before the split, 49mm after the piping splits into two pathways to the dual mufflers) to 70mm OD, you end up with a greatly reduced amount of room available for critical clearances. On top of that, larger diameter tubing can't be mandrel bend into as tight of a radius as a smaller diameter pipe. These two factors make it difficult to get a big aftermarket exhaust system to fit 100% perfectly.

Last thing to consider: not every S2000 is going to be exactly the same. How the rear subframe is bolted to the car can throw things off by more than 1/8" left to right, which is enough to make an exhaust that cleared everything on the vehicle the manufacturer used for test-fitting their design rub slightly on a different example of the same model car.

EGbeater

REAR TIP FITMENT / AESTHETICS

Here's how the exhaust tip looks on the car, from many different angles. Personally, lookswise, I think the tip is about 1/2" to 5/8" too long. But, the longer the exhaust tip, the better job it'll do of keeping black soot of the bumper/back of the car (in theory at least). The fact that the tip is off-center to the right is not TOO bad, IMO. Everyone that I asked at the autocross event "What do you think of how the tip looks?" didn't notice it was slightly off-center, until I pointed it out them. But maybe they were just being polite...

























SOUND QUALITY / DRONE

SILENCER INSTALLED

With the silencer tip bolted in, the exhaust is nearly as quiet as the OEM catback. I would say that if the OEM exhaust rates a 1.5 on a scale of 1 to 10, from quiet to unbearably loud, then the Forcewerkz exhaust with the silencer installed is a 2.

To my ass dyno, it definitely feels like using the silencer bottles up the engine and hurts power compared the OEM exhaust—not at all surprising, considering the OEM exhaust has two 46mm outlets and the Forcewerkz silencer is a single outlet of only 36mm.

SILENCER REMOVED

At this point I only have about 250 miles on my Forcewerkz exhaust. Some people say a new exhaust system will get tiny bit quieter and have a smoother tone once it "breaks in." I'm not sure if that's really true or not... I can't see a very thin layer of exhaust particulate on the inside of the piping making that much of a difference, but I just wanted readers to know that in the video below, at the time I recorded it, the exhaust only had about 20 miles of in-town driving on it.

I have not owned other aftermarket exhaust systems on my S2000, so I don't have a good point of reference for how loud or drone-y a catback on an S2000 can be. I do have a B18C1-swapped EG Civic with a 2.5" catback with a high-flow cat and straight-through muffler, which I consider fairly loud; and I had a 80mm full titanium catback on my Evo, which was equipped with a 3" test pipe and also had its rear seats removed, so despite being turbocharged it was a very loud exhaust inside the car. I have also driven my Civic at the track with only a turndown pipe after the header (and I drove it to the track and back like that) so I'm familiar with what a horrible, earsplittingly loud N/A Honda exhaust sounds like.

Regarding overall volume, I would say that the Forcewerkz 70mm exhaust is very quiet for a large-diameter, single-exit exhaust on an S2000. I would probably assign it a 4.5 on the ten-point scale (remember that I gave the OEM catback a score of 1.5). Around town, the exhaust is very mild and I doubt most people who are used to aftermarket exhausts would consider it loud at all. And at WOT, from 6k to redline, I would actually like it be a little louder (listen to the audio in the video clip below starting at 4:03).

In the all-important "drone range" of 3k to 4k rpm however it can still be too loud and annoying, especially on long trips when you're on the highway driving at basically the same RPM and throttle position for hours.

I think this exhaust has excellent sound quality and virtually no drone (what people consider "drone" is subjective of course). I drove over two hours (both ways) to and from my autocross event this past weekend, and I was prepared with ear plugs as well as the silencer tip in case the exhaust note on the highway was unbearable. I didn't have an issue with it: I found the general tone of the exhaust pleasant and was able to listen to the radio during the drive. When you're at less than 15% throttle, there's actually still more wind noise coming through the soft top than exhaust drone. All that being said, the Forcewerkz exhaust is certainly much louder and more annoying on the highway than the OEM Honda exhaust though (it's impossible to make a single-exit, 70mm exhaust with a straight-through muffler that isn't louder or dronier than the OEM dual-exit exhaust system with two double-pass mufflers).

The amount of "drone" you hear in-cabin is directly related to throttle position. By my VAFC2, between 2% and 15% throttle opening, there is no drone. With more than 15% throttle, the exhaust noise/drone gets louder and "more drone-y" in tone up to around 35% throttle. Beyond 35% throttle, there is enough airflow through the exhaust system that the droning tone is gone (but the exhaust will still get louder the more throttle opening there is, of course). I never heard any closed-throttle, decel rasp either. Note that right now, my Forcewerkz catback is bolted to the OEM cat and OEM header; it will likely sound different with a high-flow cat.

Video clip (five minutes long, with plenty of cruising at part-throttle in 5th and 6th gear):

http://youtu.be/tIiuF0UbAJw

POWER INCREASE

I do not have a dyno graph for this exhaust with no other mods/changes, nor will I later. I did however do a baseline dyno for my car 100% stock, and will go back for tuning when all my exhaust/power mods are installed (ceramic coated PLM header, 70mm Berk HFC, VAFC2). So I'll have a comparison for bone-stock on my car, versus modified/tuned with the Forcewerkz exhaust.

By the seat of my pants, I would say that my car has definitely picked up a little power with the Forcewerkz exhaust, even with retaining the OEM cat. The throttle response in the mid-range is better, and once the car is in VTEC above 6200 rpm, it pulls a little bit stronger. As unreliable as ass dyno readings are, I'm still pretty confident there's a 4 to 5 whp gain somewhere in the powerband, even if the peak gain is fairly inconsequential at 2 to 3 whp. To get optimal power gains with a 70mm exhaust, you need to have the supporting mod of a 70mm high-flow cat or test pipe + tuning.

EGbeater

UPDATE: As of March 14, 2014, I've replaced the OEM header and OEM catalytic convertor that was previously installed upstream of the Forcewerkz exhaust on my '03 AP1 with a PLM header (ceramic-coated by Applied Plastic Coatings, Wheatridge, CO, with "Turbine Coat" or Cerakote V-171) and a Berk 70mm high flow cat (HFC).

Changing out the OEM header and cat for the aftermarket parts has two results that directly affect this review on the Forcewerkz exhaust system: the sound of the exhaust overall changed, as did the fitment. However, both changes were slight, and positive, as I'll detail below.

SOUND QUALITY (WITH 70MM HFC)

As others on s2ki have reported, replacing the OEM cat and swapping it out for the high-flow cat made the Forcewerkz exhaust less drone-y. At idle and probably in general, the tone of the exhaust is slightly deeper, and I believe it's slightly louder as well whenever throttle position is above 15% or so. However, whenever you're at minimal throttle opening, it is (IMO) NO LOUDER than with the OEM cat.

AND, the tone of the exhaust is more pleasant as well. With the Berk 70mm HFC installed, I would say that my Forcewerkz exhaust has no drone at all.

Is it sometimes still much louder than I'd like it to be on the highway, at more than 15% throttle opening, between 3k and 4k rpm? Yes. But does it drone? In my opinion, no.

JUNE 10, 2014: Here are some recent in-car video clips of my car on-track with the Forcewerkz exhaust (with PLM header, 70mm Berk HFC, and no silencer tip of course). Unfortunately there is some wind noise in the audio, as I'm required to run with both windows down.

Note that in these videos you can definitely hear the exhaust sounds from other cars ahead of or next to me on track, so don't mistake that for the sound of the Forcewerkz exhaust on my S2000.

http://youtu.be/sdkda2SCQO4

http://youtu.be/J6P2CCZvz7U

In these two videos, I'm using a skeleton case for the GoPro, so the audio is a little clearer. Either way, you can get a sense that this exhaust is not really very loud at all, even at WOT, high-RPM, and without the silencer:

http://youtu.be/H68pYGoQRZY

http://youtu.be/_TyTE_Y88ik

SUBJECTIVE POWER INCREASE (HEADER & HFC)

The combination of the PLM header and the HFC has definitely improved my car's power a bit. It's not a night-and-day difference; I would guess that the peak HP gain is only about 5-6 whp, and that the midrange gain (between 6k and 7.5k) is maybe 8-10 whp or wtq. But on a fairly low-HP, lightweight, and N/A vehicle like the S2000, it's significant.

The best way I can describe the improvement subjectively is that my car feels eager to rev all the way to 9k now, whereas before, it felt like I was just getting more noise than actually accelerating the car any faster when I revved it past 7k rpm @ WOT. The throttle response—i.e., the sensation of acceleration just after you step on the gas pedal—is improved as well. Sometime down the road I'll post the before and after dyno plots for my car, with an all-stock exhaust system and the OEM header and cat; versus my car with a V-AFC II, the PLM header, the Berk 70mm HFC, and the Forcewerkz 70mm single-exit exhaust.

REGARDING THE FITMENT / CLEARANCE ISSUE TO THE PASSENGER AXLE

In my previous posts, I described how my Forcewerkz exhaust has rubbed against the axle bolts of the passenger-side driveshaft, causing a dent to the exhaust tubing. While this is primarily a result of the exhaust's design being off, I've since discovered that my passenger side motor mount is completely broken (torn into two pieces). This means there was substantially more engine/exhaust movement going on during my autocross and track-day events than there should be, and the interference issue with the Forcewerkz exhaust and the passenger-side driveshaft was exacerbated by the bad mount:



REGARDING THE FITMENT / CLEARANCE ISSUE TO THE OEM REAR SUSPENSION CROSS BRACE

Others who installed the Forcewerkz 70mm single exit exhaust on their S2000s have reported that they could not reinstall the OEM lower cross brace because the resonator canister of the Forcewerkz exhaust hung down too low.

After swapping out the OEM catalytic convertor for the Berk 70mm HFC, I now have MORE clearance between the OEM cross brace and the canister. At this point, I could remove the washers I used as spacers to create more clearance between the OEM brace and the exhaust, but haven't bothered to do so yet.

EXHAUST COSMETIC UPDATE

Now that I've put about 140 miles on the exhaust while lapping at a local road course (High Plains Raceway, click here for a video), the entire exhaust's piping and the exhaust tip has turned bronze-ish gold from heat (the muffler and resonator canisters are still polished "chrome"-looking as they're farther removed from the hot exhaust gases flowing through the exhaust). This is normal and to be expected, but I still thought I'd mention it.

Keep in mind that driving on a road course for 20 to 30 minutes at a time—much of it at wide-open throttle, except for corners and braking zones—makes for a VERY HOT exhaust system. My exhaust turned bronze/gold after five 20–30 minute-long sessions like this in a single day. If you only use your S2000 as a street car, you will never get your exhaust as hot as I did, unless you also take your car out to the track (and by "track," I mean "road course," not "drag strip").

Here are some under-car pictures of the exhaust on my car with the new header and HFC (and one shot of the header in the engine bay, just for fun ):













WEIGHT SAVINGS OF THE PLM HEADER & BERK 70MM HFC VS OEM PARTS

Since accurate information about weight savings is fairly hard to find online (and people's guesses are usually wildly optimistic), I'm volunteering this info for people who are race-prepping their cars and need to know exactly how certain modifications will affect their car's weight, and for tweaky, obsessive-compulsive people who simply enjoy knowing how much weight they're saving off their car.

OEM AP1 S2000 catalytic convertor (the catalytic inside appears intact and undamaged; with OEM gasket and 3 nuts): 12.71 lb
Berk 70mm high-flow cat (no hardware or gasket): 4.91 lb
New hardware and gasket for HFC: .28 lb
Exact weight savings of 70mm HFC: 7.52 lb

OEM AP1 S2000 header, including both OEM heat shields and heat shield mounting bolts: 22.50 lb
OEM header mounting bracket (with one mounting bolt) that cannot be reused with an aftermarket header: .30 lb
PLM header with Cerakote V-171 ceramic coating: 10.86 lb
Plug for PLM header's additional O2 bung (needed unless you're installing an additional O2 sensor for a wideband O2 gauge): .08 lb
Spacer for donut gasket on PLM header: .14 lb
Total weight of PLM header as I installed it: 11.08 lb
Exact weight savings of PLM header over OEM AP1 header: 11.42 lb

Combined with the 20.55 lb weight savings of the Forcewerkz exhaust over the OEM AP1 exhaust, I've saved 39.49 pounds on the exhaust system of my S2000.

EGbeater

June 10, 2014: Now that I've put almost 500 miles on-track on this exhaust, a couple updates. Overall, I'm still very much liking this exhaust for the sound quality, weight reduction, and power gains. I recently drove more than 1,000 miles on the highway with it (from Colorado to Topeka, KS, and back, for a NASA track weekend at Heartland Park Topeka) with the silencer tip... couldn't even hear the exhaust on the highway over the wind noise coming through the soft top driving at 80 mph. Definitely nice to have that option to muffle the exhaust entirely when you're on a long trip and don't care about hurting the car's power output.

So, I've come across a couple additional minor issues, so I'll describe how I addressed them.

With the cornering forces generated at the track (I'm on 255/40-17 Nitto NT01s front and rear), I found that the additional bracket for the Forcewerkz exhaust that attaches under one of the bolts for the driver's side diff mount won't stay in place. Once the angle of the bracket slips and changes, the exhaust's left-to-right alignment is compromised, and the exhaust tip can get off-center enough to contact the bumper cover.

So, I added a black oxide screw that goes through a small hole I drilled in the OEM suspension subframe to fix the exhaust bracket at the angle I want it at (which is slightly different than the angle I originally set it to). Since then, no issues at all of the exhaust bracket moving:



You'll also note that there's a couple of plastic zip ties wrapped around and through the rubber hanger... again, due to cornering forces at the track (and the fact that there isn't a bend or flare at the ends of the hanger rods) the rubber hanger was working its way off the ends of the hanger rods.

The zip ties keep this from happening. It was a temporary fix I made at the track, as I figured the heat from the exhaust might melt the plastic zipties, but it's been fine for 300+ track miles now, so I haven't bothered to replace the plastic ties with stainless steel ones.

flanders

Great review

Jet3010

This is a really comprehensive review, thank you for taking the time and effort to put up something of this quality. As a note when I had my Berk 3" single it came really close to the CV axle shafts as well enough that it developed a scrape like you mentioned.

xraymd

Great review! On my AP2 the muffler is within 1/2" of the bumper cover, and after the system expands when at operating temps it touches the cover. Pyrometer readings were not high enough to induce melting (So far) but it probably will require a trip the muffler shop for fitting. I think about 1/2" can be taken off the midpipe section before the resonator which would also move the resonator forward--given the angle it takes, this should, maybe, increase clearance around the lower subframe brace. I didn't hav problems with axle contact, and finagling the OE muffler hangers I could get the exhaust tip fairly centered and away from the bumper cover.

EGbeater

Thanks for the feedback Jet3010 and xraymd!

With 3" (76.2mm) exhaust piping vs 70mm, there's roughly 3mm less clearance in any direction, so your experience doesn't surprise me.

However, if the manufacturer of the Forcewerkz exhaust changed where (or how much) the piping bends near the axle bolts, I believe the clearance issue could be resolved completely... but you never can tell for sure until a new prototype is made and tested in the real world (i.e, under actual driving/racing conditions).

s2sik

I purchased this several weeks ago and still haven't installed it because I can not get the silencer out.

I have tried everything.. Even a bar that fits inside to pull it up and out.. No luck.. It was preinstalled and wedged so deep in its stuck.

I am considering cutting it out from the inside. I have owned a long list of exhausts for the s2000 and this process so far has disappointed me.