SPB Build - Test and Tune 2

After a successful test and tune at Willows I brought the car home and immediately run into issues. The idle is not stable and there is a terrible squeal at startup. The squeal is likely a starter about to go which is an easy fix, however the idle has been difficult to troubleshoot. I took the SPB into Edge (my preferred race shop) and they could not identify the source of the idle issue as it was sporadic, at least that is how it started. While it was in the shop I had them replace the exhaust as the one I got from Vali Motorsport was not to my standard. I also wanted a steering wheel angle sensor added to the AIM system for driver development. Edge did a custom fabricated mount for the steering angle sensor using an AIM pulley sensor rather than a string pot sensor. We also installed a Patrick Motorsport exhaust which leverages Magnaflow mufflers with custom tubes and mounts. This raises the exhaust from below the bumper to the center of the bumper which cleans up some of the under air flow but also gives it a nice look. By using Magnaflow I can easily replace the mufflers over time as needed. We believe this will allow me to pass sound at Laguna but we will have to test that. If I can’t pass I can easily add Laguna pipes off of the exhaust tips. With all this work done it was time to do a test and tune at Sonoma on a NASA race weekend. I was not ready to race given the state of the car so I entered as HPDE 4. As it turns out this was the largest NASA weekend EVER so the field was deep with mixed cars. Lots of passing and being passed which gave me a sense of a race without the stress of a race. A good way to shake the car down. Here is what we learned….

Custom mounting plate for steering sensor

The idle issue went from sporadic to constant which was annoying but actually helpful because Edge was able to experience the issue and then begin to troubleshoot the cause. I must have stalled the car 40 times in one day because the idle was all over the place. It was so annoying that I skipped the last session of the day as I couldn’t deal with it anymore. Every time it stalled I had to do the startup sequence all over again (kill master power, turn on master power, turn on ignition power, startup). All the power cycles ended up causing issues with my AIM (more on that later). For the idle issues, our hypothesis was a vacuum leak and we agreed to chase that down with smoke back at the shop. We did end up finding some vacuum leaks which we resolved but none were the cause of the idle issue. As it turns out the AIM TPS that Vali Motorsports spliced in was introducing signal noise to the ECU which didn’t allow the ECU to manage the idle properly. Once we disconnected the TPS the idle held steady. What we discovered was that Vali used the wrong type of AIM wire harness for the TPS. They used a temp wire harness which introduced a signal back into the car ECU. As soon as we changed out the AIM wire harness to the correct harness type the issue was solved.

During our test at Sonoma I also found that the AIM shift lights were not working. This ended up being an easy fix but let me explain my journey. The steering wheel I picked ended up blocking the primary shift lights on my AIM dash. To solve this we simply mounted an AIM aux shift light module which raised the shift lights above the steering wheel. That meant I actually had two sets of shift lights with only one actually visible due to the steering wheel. But for some reason we could not get them to work properly. After a couple of hours messing with the configuration I found out that if I simply disconnected the aux shift lights the shift lights on the AIM dash worked just fine. Something about having the aux shift lights wired into the AIM system was causing an issue. The solution is easy…..just pick out a different steering wheel that doesn’t block the AIM dash primary shift lights and remove the aux shift lights. A quick run to Wine Country Motorsports at Sonoma and I found a larger steering wheel that allows me to see the shift lights on the AIM dash. While we found a solution, we still don’t know why the aux shift lights are not working properly. Chalk it up to AIM tech being difficult.

Sabelt rally wheel was just large enough for me to see the AIM dash shift lights

The time behind the wheel also gave me valuable insight into minor adjustments in the cockpit. I am sure I will find more ways to make improvements on visibility, comfort, and convenience but for now I have solved most of the things I have identified. During the day a new noise developed which was a metal rattle near the exhaust. We identified a loose clamp and now the noise is gone. Back at the shop we chased down a few other minor issues and we are now working with a well running race car.

My thoughts so far. The SPB is a great platform for driver development. It’s a fast momentum car which requires the driver to drive at the limit consistently in order to put down fast laps (I am not there yet but I am confident I will get there over the next 2 years). The car is forgiving but it does not drive itself like many modern day cars. There are no nannies that are going to save you which is exactly what I wanted in order to become a better driver. Vali Motorsports gave me a lot to work with, but I have run into way too many problems on a fresh build. A race car is never perfect and there are always race car problems to deal with. But I have found used parts on my car that were part of the race car “upgrades”. I have found loose suspension parts. The car had a fresh rebuilt engine and tranny, yet I have multiple vacuum leaks, some minor oil leaks, some old parts left on the engine that needed replacing, and basically a non-functioning car due to a poor AIM installation. I have had to return the car to Vali at my own expense to get some of these things resolved, yet I had to pay Edge thousands to resolve issues that were avoidable. I would work with Vali again but I would do it different next time. I would either have his team do part of the build and I would finish it close to home, or I would give his team more time and I would require more test and tune days before taking delivery. What is important is that I ended up with a great car…..it just took most of the year to get it in shape.