On the dyno, the AEM EMS and Speed Density intake combo took the car to a different level, even without adding a pound of boost. At 340 whp, the gains were realized throughout the entire rev band, with the greatest gains up top. The graph was substantially smoothed and the car was running better altogether, still on 91 pump. The air-fuel ratio reading from the UEGO was data-logged through the EMS software and gave a reading of about 12.5:1 in the upper rev range.
On the road, the car feels considerably faster than it was prior to the EMS, intake and cam gear conversion. Between 2200 to 3500 rpm, while still being pushed forward only by the first turbo, the Supra gained between 10 to 20 whp. At 2900 rpm, the 20 whp gain equates to no less than a 36 lb-ft gain in torque! Once the second turbo hits, it's a whole different ball game; the area under the curve tells the entire story. At about 5200 rpm, the second turbo's spool-up thrusts me into my seat harder than before, which explains why there's more than a 45 whp gain there (at that rpm it's also a 45 lb-ft of torque gain, before you ask).
Up top the gains were also magnificent. To compare, in Part 2 the Supra's final pull with an intake kit and full turbo-back exhaust ranged between 278 whp to 311 whp from 5500 to 7000 rpm. With the addition of the AEM components, the horsepower graph was remarkably increased as well as flattened, registering between 330 whp to 340 whp in the same rev range. It's these gains that tell a much bigger story than simply comparing peak horsepower values.
While a 12.5:1 air-fuel ratio doesn't alarm many tuners as being too lean for a street car, I still like to stay on the richer side of things. I had Siebels add a little more fuel in the upper rev range, bringing the ratio to 11.7:1. At this air-fuel ratio, the power came to 326 whp, but the shape of the power curve was still the same-flat up top. However, since this car will be street-driven primarily on pump gas for now, I felt this was a safer mixture to run.
Next time we'll make more power and accomplish it without changing boost pressure or the air-fuel ratio. Stay tuned.
On track-getting a feel for the carAs mentioned in the introduction, the goal of Project Supra isn't solely focused on power and drag racing. Toyota built a sports car with phenomenal handling and equally superior braking, two performance aspects that can only be fully experienced at the track.
Redline Track Events was started by fellow track junkies, Nikolas Malechikos and Chris Willard, with just a few things in mind: fun, safety and affordability. And although safety tops the organizers' priority list, make no mistake about it-Redline Track Events offers one of the best values around by keeping the entry list and price to a minimum and your track time to a maximum.
The particular track day we selected to test to participate in took place at the Streets of Willows, a track that offers a great balance between speed, safety and difficulty, which is important to consider when getting a feel for a particular car for the very first time. The Bridgestone S-03 tires and bone stock braking system weren't changed so as to keep a stock-like setup, save for 320 wheel ponies we had with the new AEM stuff.
Since the car is still using the factory intercooler and lap-after-lap driving would inevitably increase intake (and therefore combustion) temperatures, we selected to fill the car up with Sunoco's 112-octane race gas to avoid any unsparked detonation the otherwise 91 pump piss would be going through.
Like all other fuels, the 112 octane rating was achieved using the R+M/2 method. However, this fuel in particular has one of the higher Motor Octane ratings-the more important octane rating for wide-open-throttle performance-when compared to other race fuels at this octane level, with 110. Due to the elimination of the cats in the last installment, we were able to run leaded gas, which offers greater resistance against detonation. Unfortunately, leaded fuel also harms oxygen sensors over time, so be prepared for premature wear if you plan to run this stuff often.
If unleaded racing fuel is what you desire, Sunoco also carries 100- and 104-octane unleaded fuels, which don't affect oxygen sensor or catalytic converters. We purchased this fuel from Downs Commercial Fueling in Corona, Calif., but you can visit www.racegas.com for more Sunoco distributor info
On track, the Supra in its stock form is nothing short of magnificent. Although soft enough for the street, the stock suspension was a terrific match with the braking and engine power. Additionally, it seemed to work well and be extremely predictable in conjunction with the Bridgestone tires around the corners. Even with the stock-sized tires, the car seemed to grip comfortably enough at wide-open throttle from third gear on, allowing confident pressure to be applied to the throttle through each high-speed apex. In second gear, it was a different story; you don't want to be at wide-open throttle unless you're pointing straight.
The large factory brakes performed surprising well and didn't experience fade throughout the entire day, but the braking system wasn't really pushed to 100 percent, either. Thanks to the impressive tire grip, we didn't experience much ABS intervention, due in part by widening the front size to a 245/45-17 (from a stock 235/40-17). All in all, it was a fantastic and enjoyable day running with some of the other cars there, including Z06s, NSXs and WRXs. There was so much track time, we even called it a day a couple of hours early.
Although the relatively stock setup was impressive, we plan to return with more grip, handling and braking on track next time. Stay tuned.