Modified Magazine’s Tuner Shootout has become one of the most highly anticipated and hard-fought import tuner competitions in the industry. Tuners compete against each other in a variety of all out power, road race, drag race, and autocross racing events. You may remember from prior years that ScienceofSpeed has competed twice in Modified Magazine's Tuner Shootout as well as Sport Compact’s and SuperStreet’s Super Lap Battles.
We've done ok in the past - but never had the car setup with the horsepower to be truly competitive. Last year, we brought a 3.5L high compression NSX with individual throttle body induction to the Modified event. At nearly 400 whp - the car was the highest naturally aspirated car to compete - although still one of the lowest horsepower cars overall in the competition. These tuner shoot outs aren't like typical racing venues where power to weight is limited - in fact, the more power the better your score! We did well in the past with a rear wheel drive 1st place finish - but this year, we wanted to bring a car that was more competitive - and competitive means power!
We were invited to join the event in early February, which gave us about 7 weeks to prepare. We found out the magazine had decided “no more race cars” this year – this year, it would be a battle of street cars. Emissions and sound testing would be added to the competition, and the cars would be required to use the Continental ExtremeContact DW tire. The ExtremeContact DW tire has a significantly higher treadwear rating than most tires, including the OEM tire used for the NSX. We knew that traction was going to be an issue, especially for the high horsepower cars that attend these events – this was a challenge to embrace!
To fit the street car requirement, we enlisted our Sebring Silver 1992 Acura NSX. This car spends most of its life torn apart in various stages of testing for new products. The car has had one of the first built engines ScienceofSpeed designed, and at least three other engines installed for testing. In addition, it has had two supercharger systems, and the first prototype ScienceofSpeed Twin Turbocharger System installed. She’s a true research and development mule! We knew it was perfect for the competition – it was truly a street car in every respect. Full interior, emissions friendly, original shocks and lowering springs, even sat nav! We knew in building the car that power output would be important to score well in the dyno competition, but also knew that chassis control would be as equally important to deal with the limited traction of the tires.
The first item we built was the engine. The car before the event had a factory 3.0L engine installed while we were testing the factory engine configuration for the twin turbocharger system. We decided on a ScienceofSpeed Stage 1 Forced Induction Engine with the ScienceofSpeed Twin Turbocharger System. In addition to the engine, we decided the event would be great to campaign several new products we have been working on – including a replacement for the now discontinued AEM EMS for the NSX, our new high flow fuel system, as well as the application of Garrett’s new GTX28 turbochargers. Our goal was 600+ wheel horsepower – which we figured would put us in the top 25% for the competition. To achieve this number, we were required to use a commercially available pump fuel. E85 was selected due to its increased anti-knock properties and cleaner emissions output.
We are sad to see the venerable 30-1042 AEM Series 1 EMS go. This stand alone engine management system has been a reliable platform for hundreds of NSX owners around the world. With dwindling series 1 hardware left, AEM has made the decision to discontinue the NSX EMS – and with the limited NSX market, also decided to not pursue the development of a replacement. Thankfully, we were given adequate heads up by AEM – including some help from a couple key employees who are NSX enthusiasts themselves to develop a replacement solution. We’ve been working on a replacement for about a year now. The new plug and play EMS for 1991-94 will join our offering for the OBD2 NSX in the next week. This test car has been running a prototype EMS for several months now trouble free. We’re very excited to be able to put the EMS to the test on the track where its stable sensor readings and increased knock control capability allowed us to push the engine to the limit to be competitive this year.
As you may know, E85 has been the “wonder fuel” for many tuners. It is available out of the pump in many cities, has anti-knock properties near 100+ octane fuel, cooling properties, and is relatively inexpensive. In addition, the chemical structure of ethanol (85% by volume in E85) includes oxygen, which produces a cleaner burning fuel than straight gasoline. However, it does contain less energy than gasoline, and requires approximately 30% more volume to achieve the same energy quotient. This requires a pump that can deliver the flow that the larger injectors require to be used with E85. In addition, the higher manifold pressures that E85 allows increases the load on the pump from the pressure being placed on the engine side of the fuel injector. We’ve been experimenting over the past year with different pumps, fuel injectors, fuel pressure regulators, fuel rails, and power sources for the pump. For the competition, we selected the Walbro 400 LPH pump, Injector Dynamics 1000cc injectors, and Borla Induction fuel pressure regulator. However, it’s important to keep in mind that these new turbine fuel pumps have a high amperage draw to move the fuel, especially with increased rail pressures. We’ve developed a wiring kit that puts 12 gauge wire all the way to the pump using factory connectors and no cutting of the factory electrical harness. Look for this on our website in the near future.
An important part of the competition was emissions quality and sound. As far as we know, the ScienceofSpeed Twin Turbocharger System is the only one that due to its design allows dual catalytic converters to be used – one per cylinder bank. Our GT Exhaust system was selected along with one 3” catalytic converter per cylinder bank to keep emissions in check.
During tuning, we ran into several delays as we experimented with fuel pump, injector, and wiring designs to keep the fuel flow in check for the volume demands of E85. Running nearly 25 PSI of manifold pressure, the pump had to contend with a base pressure of 50 PSI plus 25 PSI of manifold pressure all while supplying 360 liter per hour of fuel to the injectors. Thankfully, with the help of Tony Szirka from UMS Tuning, we were able to complete tuning within days of the event. Unfortunately, we didn’t have enough time to complete ignition mapping for the emissions load points, and had to contend with fuel control set as close to stoichiometric as possible with wideband oxygen sensors providing additional fuel trim. The car produced 695 wheel horsepower with test pipes and 665 wheel horsepower through the catalytic converters – it also produced emissions that makes the car legal for Arizona emissions standards - all at nearly 750 bhp!
In preparation for the event, we made the decision that I would drive the car this year in all of the competition’s events. In prior years, a professional driver has driven our cars in the road course event. We felt by driving the car ourselves, we best fairly demonstrated our capabilities to our customers - hopefully making the product recommendations we make daily to customers legitimate.
The track that was decided on for the road course race by Modified Magazine was the “West” course of Firebird. The West track is a 1.1 mile course that includes 11 very tight corners. It was felt that this track would best simulate the demands of the street environment compared to a higher speed road course like the main track. The NSX does not feel as comfortable on this tight course compared to the S2000. Several of the corners required well over ninety degrees of steering wheel input where the S2000's tight ratio electronically assisted steering requires significantly less steering input.
Driving a mid engine 665 wheel horsepower NSX on 340 tread wear tires was … interesting. To make the best of the tires, we selected 17x8.5 and 18x10.5 wheels which would stretch the width of the contact patch to increase lateral traction. We experimented with the tires some and found that they performed best on the NSX with starting pressures of 30 PSI front and 33 PSI rear. This resulted in a hot pressure of about 37 PSI front and rear. To achieve the best traction from the tires and keep the suspension as settled as possible, we used shock absorbers with 450 lb/in springs. We were able to reduce sway with our adjustable sway bars, at about 150% stiffer than the factory bar up front and 75% stiffer in the rear. A key to keeping the suspension geometry in check was the use of the ScienceofSpeed non-compliance toe links and suspension beam bushings.
The one interior mod we did (which was allowed) was a bucket seat and harnesses to keep me anchored to the car and in touch with the chassis. The Recaro Pro Racer seat I feel is one of the most significant improvements you can do to any car that will be used exclusively for track use. The supportive seat adds head protection from lateral movement and fits my body type like a glove. By not moving around in the seat as much, I could more easily deal with the traction and keep the car in check. I’ve been giving these tires a hard time – but honestly, they weren’t that bad for the tread wear they were rated for – in fact, for what they were designed for – they are a fantastic tire. The tread wear ratings are supposed to be uniformly applied, however I hear from experts that there is indeed a wide variance in the traction from manufacture to manufacture. I have not seen the photos from the magazine photographers yet, however, I hope they caught some of the tail wide out smoke pouring from the rear that the tires produced after five laps once the tires said “NO MORE ABUSE!”
In addition to the road course event, the cars were also tested on the quarter mile track. Grip was a big issue, as you can expect with such a hard tire, but it made for a good learning lesson. I’ve been down the drag strip that is also a part of Firebird main more times than I can count in the race car, but only once before from a stop with the light tree in place. After several passes it became clear that despite the wheels spinning in first through fourth gear, it was best to keep on the throttle in second and especially third and fourth gear as the wheels spinning would generate heat and increase traction as the tires began to slip. The event also had two street cars run in the quarter mile to compare how the cars in the event with the Continental tires compared to other high power street cars with traction control and relatively sticky street tires. It was nice to see this 20 year old car keep up with McLaren’s MP4-12c with its advanced traction control allowing it to keep the power to the ground.
The results of the competition will be featured in Modified Magazine’s July / August issue. Check out Modified Magazine’s website here: http://www.modified.com/
This was indeed a team effort, and everyone at ScienceofSpeed pitched in to make it a successful event. Overall, we were very pleased with the results and we feel we represented the NSX community well. Despite being the “oldest” car in the competition, the NSX’s abilities have been demonstrated to be quite competitive with modern sports cars, especially with a few extra ponies to bring its power to weight on par with modern high performance standards. With the right tuning, it is a car that I suspect will remain competitive even once its successor arrives.