INTRODUCTION:
In May 2003, I developed an article for to4r.com entitled Clash of the Titans. Four exhausts were invited to a proposed shootout held at SP Engineering in the City of Industry, CA. Invited participants included the GReddy Power Extreme, the VeilSide Titanium, the Blitz Nur Spec R and the HKS Racing Titanium. Of the four exhausts, three showed up for the shootout (the Blitz Nur Spec R was a no-show) which was, ultimately, won quite handily by the HKS Racing Titanium.
Fast forward to May 2005 and circumstances have changed quite a bit. For starters, this time I’ve written the sequel to Clash of the Titans I for SupraForums, by all accounts considered the largest, most successful and influential Supra-based website on the Internet. Secondly, the HKS Racing Titanium has some very serious 4-inch exhaust competition. No longer can it expect to win exhaust shootouts just by showing up. In Clash of the Titans I, it was the biggest and straightest exhaust in the competition, so no surprise that it out spooled, out powered and out torqued the competition. The big question for Clash of the Titans II is would the HKS be able to stand up to bigger, better and much newer competition? Read on and find out.
THE EXHAUSTS:
As the MKIV Supra aftermarket has evolved and matured in the U.S., a few innovative and courageous manufacturers have stepped up to go head to head with Japanese aftermarket powerhouses, such as HKS, GReddy, VeilSide, Blitz and others. One area where this trend is apparent is in the research and development of big-bore 4-inch exhausts for the MKIV. With all the new, and some old, competition, it only made sense to gather together all of the mass produced 4-inch exhausts, identify a car capable of exploiting these exhausts in its STREET tune, bolt ‘em up, lash the car down to SP Engineering’s Dynojet chassis dynamometer and clear up all the “mine is bigger, and badder, than yours” smack talking so prevalent in the Supra community. First up, the new kids on the block:
One of these “new kids” is Wide Open Throttle Motorsports (WOTM), the progeny of founder and owner Ryan Woon, a guy who has also developed somewhat of a reputation as a pretty good engine builder and six-speed drag racer. Wanna’ see how well WOTM parts work on a big power MKIV Supra? Pay attention the next time you see Ryan’s car at the races or in a show and shine. The WOTM exhaust is a two-piece all stainless steel sewer pipe that weighs in at an even 22 lbs. Add the assorted hardware and bracketry and the total weight goes up a bit to 24.3 lbs. It also has an exhaust tip ID of 98 mm and a piping OD of an even 100 mm.
Remember the old biblical story of David and Goliath? Well, we have our own modern day Goliath in the form of the HorsepowerFreaks (HPF) Goliath 4-inch exhaust for the MKIV Supra. All it took was one email from me to Chris Bergemann, founder and owner of HPF, and he immediately agreed to participate in the shootout. “Where do I send it and when?” was all he asked. This exhaust is fully polished T-304 stainless steel and comes with a patented Aero Turbine muffler that is said by its manufacturer to actually speed up exhaust flow. Weighing in at an even 24 lbs., 24.5 lbs., with the “V” band, the Goliath came ready to do business. We measured the ID of the exhaust tip at 103 mm, and the piping OD, like the WOTM, came in at 100 mm.
The third company in our new kids threesome is BoostLogic, builder of very high quality, turbo kits, drag race auto trannys, crank dampeners and exhaust systems for the MKIV. Founded and owned by Kean Wang, a name well known to MKIV enthusiasts everywhere, the Boost Logic is also a fully polished stainless steel 4-inch exhaust that, according to its supporters, is ready to seek out and destroy the competition. Kean immediately agreed to ship an exhaust to SP Engineering and let me know in our back and forth emails how enthusiastic he was about the proposed shootout. The BL had the largest exhaust tip ID of 123 mm and a piping OD of 100 mm. Although appearing to some eyes to be physically larger than the GReddy and WOTM in particular, the BoostLogic 4-inch was the lightweight of the group, weighing in at a feathery 19 lbs., and 21.5 lbs., with hardware.
Although the product of GReddy, an old school Japanese aftermarket manufacturer, the Evo II 4-inch is not all that well known in the Supra community and was never really marketed in the U.S. Well, the results of this shootout may change all that. Made of mild steel with a polished stainless steel canister, this particular exhaust is owned by Ju-Hon Chan, the owner of the car used for testing the competing exhausts. Acquiring this exhaust on a special order basis, Chan is one of the more spirited and enthusiastic supporters of GReddy’s entry into this comparo. With matching 95 mm exhaust tip and piping internal and external diameters, the GReddy’s apparent advantages are only partially offset by its mild steel construction and our forgetfulness in weighing it on the day of the competition. This oversight will be corrected within a few days at most.
Last, but certainly not least, is the HKS Racing Titanium, an exhaust considered by many to be the undisputed champion of big-bore exhausts. Here’s the deal, though. It doesn’t matter what you and I THINK; all that really matters is objective performance (and price, looks and perceived value). Sure, it’s won virtually every competition in which it has competed, but none of those competitions, to our knowledge, matched the HKS with like-sized opponents. No light-heavyweight competition here; the HKS was, for the first time, going up against other industry heavyweights. This exhaust came off my personal car and weighed in at an even 26 lbs with everything included. As most of you know, only the slip-fit muffler assembly is made of titanium; the big-bore piping is made of polished stainless steel. Measuring the exhaust tip revealed an ID of 111 mm and, like all the others except the GReddy, the piping OD came in at 100 mm.
THE CAR:
Black, sleek and stock bodied except for the carbon fiber TRD hood, this car, with polished OEM wheels, epitomizes all that we’ve come to know and love about the MKIV Supra. Owner, Ju-Hon Chan, graciously volunteered the use of this car for Clash of the Titans II long before the arrangements were made to acquire the various exhausts. Because of significant demands on my time, causing a number of unavoidable delays in the proposed competition, Ju-Hon used the intervening time to build up his car. Although the mod program has been comprehensive and balanced, our focus is, necessarily, on the motor, as these exhausts love to make big power.
Heading up his list of motor mods is a pair of HKS GT2835R turbochargers (56-trim; 0.61 A/R) with custom SP Engineering 100 mm intakes and JetHot 2000 ceramic coating on the twin HKS manifolds, turbines and downpipes. HKS rates these turbos at 420 ps each, with the only difference between these turbos and the 56-trim GT2835s being the 100 mm intakes. Also from the HKS catalog are 264-degree cams, intake and exhaust, its original five-bolt cam gears, the Type DLI ignition amplifier, EVC 4 boost controller, triple-disc clutch with slave cylinder mod, 1000 cc fuel injectors, dual in-tank fuel pumps and the HKS F-CON V-Pro EMS.
The HKS pieces are ably assisted by a built shortblock with a lightened, knife-edged, polished and balanced crankshaft, Crower billet steel connecting rods and forged JE .040 overbore pistons with a static compression ratio of 8.5:1. The shortblock is sealed with an HKS metal head gasket, and topped by a ported and polished cylinder head stuffed with Ferrea valve train components. Although not yet tapped out, the motor recently made 813 whp on 100-octane unleaded and recently completed its C16 mapping. As noted earlier, the decision was made to dyno the car utilizing its STREET tune, as it was felt everyday performance was more important to the community than dyno-optimized performance. Besides, no tuning was allowed, so we had to be sure the tune was safe and that it would allow repeatable and reliable results.
THE PROCESS:
In any testing of competing products, you want to limit, to the extent possible, variables that might negatively impact the integrity of the test protocols employed, or the reliability of the results generated. For this particular event, we agreed before hand to use C16 racing fuel, boost to 1.8 kg/cm^2 (25.56 psi) and to dyno each exhaust a total of three times, with no cool down period between dyno runs. As with Clash of the Titans I, we proposed a cool down period of one hour between the last run of a particular exhaust and the first run of the succeeding exhaust, although we opted to reduce the cool down period to 45-minutes once testing began.