Spec Racer Toyota

                     by Midwest Spec Racer, Inc.

                        Makes it's first attempt at the grueling

   25 Hours of Thunderhill

               December 3rd, 2005

How we wish the caption on this picture was MSR/Players Racing finishes 1st and 2nd overall at the 25 hours of Thunderhill. We did; however, finish 1st and 2nd in class which is of no consolation to us at all. Unfortunately, this trip turned into a very expensive test session where we discovered some problems with engine oiling that had not been encountered at the Aspen track where most of the development had been done by a dozen cars during the course of the summer. Thunderhill is made up of some very high speed turns where we were pulling G force peaks in excess of 1.54 both left and right with sustained periods in excess of 1 G for more than 43 seconds per lap, which is 35% of a typical 2:02 lap. Since the Accu-Sump system is good for 2 seconds of starvation and takes 3 seconds to refill, this was more than that system could handle. It is obvious that at tracks other than our friendly little Aspen we will be installing a dry sump oiling system on the car. That said, let's move on to the fun stuff.

The 1st place car in ESR was driven by a team of drivers from the Autobahn Country Club including: Jason Kubasak, Mark Jurczyk, Steve Kohli & Bob Lojkovic. Jason is quoted as saying, "The Aspen Toyota is so far superior in handling, braking and power to the Spec Racer Ford it doesn't even seem like the same type of car.  If it were not for the problems with the engines, I think we had a legitimate shot at an overall win." 

The 2nd place car in ESR was driven by a pair of drivers from the Aspen Racing & Sports Car Club including: Claudia Potamkin & Larry Winnerman as well as a pair of very enthusiastic drivers from Autobahn; Dave Teitel & Joe Turner. Claudia is quoted as saying, "That was the best one hour of my life," after getting out of the car from one of her runs. Joe just continues to say, "WOW."

I would like to thank the staff of Toyota Racing Development for their assistance during the 2-year development of this car. Chuck Wade has offered more technical advice than you can imagine. He actually worked for Renault/Jeep Sport during the design/prototype stage of the original Sports Renault. His knowledge of the car, combined with Toyota knowledge, helped immensely in some of the suspension and driveline engineering.

David Leong got some nice action shots such as this one with the engine failure. Notice the aerodynamics coming off the adjustable rear spoiler.

Our crew consisted of the entire full-time staff at MSR including: Steve Fenske (chief), Kendall Smith (front impact), Kevin Wood (rear impact), Forrest Wood (front jack) and William Marotta (fuel/RF tire). William also brought his wife, Kim, who kept us fed as well as doing statistics. In addition to that, we brought in an old-time crew person from Denver who has lately been working corners back home, Fred Drake, AKA Fast Freddie (LF tire). A local driver, Dave Harriman (fire safety/RR tire), brought us great local knowledge. Wayne Kubasak (LR tire) is Jason's dad and was great help to William and Steve during the 1 hour 13 minute motor change under green flag.

We elected to run the race on Hoosier R45 compound racing slicks from a FC (front) and FSCCA (their front on our rear). The tire usage rate was planned to be one set every 2 hours. We brought 96 mounted tires to the event and scrubbed all of them Friday. We could change a set of 4 in about 1 minute. As it turned out the fronts were looking like they could last for 3 hours while the rears were gone in about 1.5 hours. The suspension has a special dual range adjustment feature that allows us to obtain the "near zero" camber numbers that slicks like. You will see that in 2 pictures later.

Our darkness was turned into daylight by a clip-on light bar with $1,500 worth of HID lights that had a total starting load of 42 amps, but dropped down to 18 amps after the startup surge. This bar clips onto heavy duty front hood pins and connects in about 20 seconds. Watch out for the duck!

The muffler of choice for the Aspen track is the DynoMax turbo style pictured here. We have tested another bullet style straight through design, but this one is quieter and made more power than the other. Notice our rear lower body cutout is narrower than the SRF. We did that to improve the appearance of the corner after cutting out the wheel well. It just didn't look right with a sliver hanging down behind the tire, plus I think this keeps some of the strength in it.

We have added an adjustable rear spoiler to the tail that has a range of 0" to 1.5" for the high-speed handling needs, which we anticipated at Thunderhill. In the end, we ran it full up.

This is a great shot of the wheel cutout much as it may appear on the SRF in the near future. I have several sets of Weld wheels for sale after this event at 25% off the original retail price. We will sell as sets, individual wheels or taken apart into components. All used for 1.5 hours or less, some for only 8 minutes of scrubbing. None of them were bent or scratched.

Rufus is inspecting the inside of the rear wheel cutout to decide if it needed any reinforcement. He came to the conclusion that it did not. You can see this tail had been grafted at the peak of the wheel arch, which should have created a weak point. After 10 hours of run time, even with the extra aero downforce, this tail exhibits no stress.

Our engine selection criteria for this conversion was most influenced by the need to have a rear side exhaust configuration to keep things simple for heat management and packaging. We ended up choosing the Toyota 1ZZFE from the Corolla which is possibly the most plentiful small late model engine in salvage yards today. The cool header is designed by MSR and mass produced by DC Sports. Also notice the modern individual coil over spark plug arrangement eliminating plug wires. This view also shows the removable left rear upper control arm bracket, which enables pulling the transaxle out the left side of the frame without disturbing the engine. Inversely, the engine may also be pulled out without disturbing any transaxle mounts. The engine/transaxle are solid mounted at 5 points. The driver doesn't complain of any vibration or harmonics, but blue threadlocker is your best friend when working on this car.

The short nature of the left axle halfshaft was our first real development issue that has proven to be resolved by Frank at The Driveshaft Shop. The inner tripod joint was just not up to the high angle and torque loads it was subjected to. He designed and built a custom inner CV joint that replaces the stock Toyota tripod with a large, deep plunging 6 ball joint. Post race inspection has shown this to be the cure to our only real problem encountered at Aspen. The upper ball joint is replaced by a 5/8" rod end with reversible side plates to accomplish the dual range camber adjustment feature. This allows for adjustments between the two ranges anywhere between -6 degrees and +1degree without bottoming the adjustments or exceeding the 9/16" rule. Lower suspension arms, shocks, sway bars and the upper control arm are from the SRF. Rear spindles & bearings are Toyota Echo slightly modified for clearance.  The center hub is custom to accommodate the bearing to a larger CV joint. Brake calipers and ventilated rotors are from the front of the Toyota MR2 Spyder. The toe links are custom with dual wrench flats near the outboard end so they are easy to reach. There is a feature to allow for bump steer adjustments at the inner and outer end of all 4 corners of the car. Our transaxle is the 5 speed from the Toyota Celica GT. It features needle bearing races inside all of the rotating gears with approximately 20% larger components in the entire the systemlending greater strength. The gear ratio is nicely suited to the top speed forecast of the vehicle running out of torque and RPM at the same time in top gear in the mid 130 MPH range. (not yet tested)

The fresh air intake system by AEM draws a cool charge from the left side pod. A future side intake gill may be in the works for both the oil cooler and the air filter if we do a body revision.

The seat on the 12 car was modified to move forward about 3" to accommodate the custom built extended forward fuel cell that has a 13-gallon capacity.

Here you can see the available firewall area clearance made possible by the smaller custom coolant tank and the compact alternator.

We did a couple of things to these cars that will not be standard production. You can see the ATL dry break fuel filler and the fluid discriminator valve to help us accomplish a fill rate of 0.5 gallons per second. I have since discovered a way to replace the bulky discriminator with a larger -8 version of the flapper/check valve that the SRF uses and probably improve the fill rate by another 50%. The discriminator turned out not to be the total answer as it had a tendency to seep in the pit lane once it had been filled. The new way I have conceived does not leak in the short term once it has been filled allowing us to drive away from a pit stop without a 5-minute penalty for pit lane fuel dribbles.

The front brakes are the same MR2 Spyder calipers & rotors as the rear. We are using a Asbestos ST43R compound brake pad which has stopping and staying power like never seen before without sacrificing the rotor or pad. We could have easily gone the 25-hour distance with no brake maintenance. The front spindle & bearing is also from the Spyder with very little modification. The front lower control arm and clevis are replaced with custom units to accommodate the odd angle of the lower ball joint stud. Notice a clear shot of the outer bump steer location as well as the reversible upper ball joint that does the dual range camber feature. We have nearly perfect steering geometry, including ackerman, since the spindle application in our case is close to the OE factory configuration. The length of the steering rack has been altered with bolt-on clevis extensions and the rack lowered to allow for proper bump steer positioning.

We are including a totally new wiring harness and fuse panel in the conversion that is professionally built with high-grade connections and materials. Features of the electrical system include 15 separate fused and labeled circuits including two expansion slots for the headlight option harness. Two relays and bypass switches for the fuel pump and soon to be extinct Accu-Sump. An hour meter and communications port round out the cockpit panel. Other features include interface connections built in for key connection points on a STACK dash and data logging systems making the installation of a STACK system the logical choice. There is a power point built in at the right rear corner for the AMB transponder as well as two universal power points; one near the battery, and the other under the dash. These power points offer ground, switched 12V, battery 12V, and a unique engine running 12V all available by plugging in a simple "flat 4" trailer connection from the parts store (I do not want anyone to butcher the harness to add an accessory.) The shifter is butter smooth and so precise I have heard it described as more like a sequential paddle shifter than a joystick. This is accomplished by using the basic Toyota cable design and changing the cables to industrial strength but with smooth operating pieces. The brackets and bell cranks have also been replaced with custom units that change approach positions and motion ratios to suit our application.

Each of these cars were fitted with 3 boxes of STACK data logging equipment more suited to a Formula Atlantic test session than a Spec Racer. Unfortunately, I had to spend unscheduled time swapping motors so I was unable to exploit their true capabilities. Next year, we will be data logging everything short of the driver's blood pressure with synchronized video to go along with it.

This is a back side view of the fuse panel with its close proximity to the AEM brand engine management system (EMS). It has the ability to be user programmable at this point, but I have the ability to lock that down in the future for a spec series. There is an internal 0.5 MB data logger of engine functions that loop records for diagnostic purposes. There are many more super advanced capabilities of this system that can be explored by clicking the AEM link on the left sponsor bar. Please keep in mind that these are options I may or may not choose to add before locking down the system. We have moved the coolant overflow to this side since we needed weight over here (the heavier duty transaxle on the left and the aluminum engine on the right has shifted weight left). Another plan for production is to move the fire bottle to this side as well as the oil tank for the dry sump system. That should be about perfect to finish off the weight distribution.

Click this link for more pictures and details during the development stage of the car.

We will be adding a few more pictures to this page with driver interest shots as they are forwarded to me.

Watch for a test of the new dry sumped SRT at a race track near you soon!

I have a development page started where I share thoughts with the dry sump engineer. I will share it with you.