As you could tell, the car was in nearly ready status as of the last post, but it was missing at least one major item.... Suspension.
I had ordered up a set of Motons between Christmas and New Years, 2010. Normal lead time was 4-6 weeks, but ultimately that turned into a few months due to work stoppages in Holland where they are built. I finally got to the point where I wasn't willing to wait any longer as the season had already started, so I change my order over to AST.
AST builds a very high end shock that is available in many levels. I chose to go with the 5200 series shocks as they are double adjustable, which in my opinion is very necessary for tuning the MX-5. They are beautiful shocks, with aluminum bodies, monotube setup, and remote canisters for adjusting the compression.
AST 5200 front shock with remote reservoir |
Along with the AST shocks, I utilized spherical bearing top hats in the front. They came with Hypercoil helper springs and main springs. The helper spring's primary purpose is to keep the springs seated when the car is jacked up. The springs that came with the coilovers were 2.5" ID, with 7"x700lb fronts and 7"x400lb rears.
AST coilovers with 7" front and rear springs |
Unfortunately, once I put everything together and bolted them to the car, I had the front of the car it it's highest setting and the rear at it's lowest and had a huge rake to the car (the rear was about 2" higher than the front and not really much lower than it was with the stock shocks/springs. As it turns out, the rears needed more threads on the shocks themselves to get the car down where it should be.
May 12, 2011 - First alignment at Fordahl Motorsports |
The grand unveiling of the car went quite well, with lots of people excited to see the car, not the least of which was Bauerspeed Racing itself!
Of course, this was to be the first actual shakedown of the car, so while hopes were high, there was also much trepidation. Bauerspeed Racing had previously run an MX-5 in CSP, so we had a good amount of knowledge from that, but that car started as a brand new, off the lot car, so it was a known quantity as far as the running gear itself. In addition, while we ultimately had Moton Clubsports on the CSP car, we didn't have the big front swaybar that we were starting out with on the DP car, so spring rates were a bit of a guess.
This new car came to the team as an automatic with 98,000 miles. While we knew that it started and drove, we had no clue as to how it would run on an autocross course. Keep in mind we were also running the stock ECU that still thought the car was an automatic.
Oregon Region SCCA #4 - 5/14/2011 |
While this turned out to be a very respectable start to Bruiser's autocross career, we learned that there was still work to be done. First off, obviously we needed to address the power issue, or more to the point, the lack of power issue. Come Monday, we shot off an e-mail to Joe of DP Tune in Texas to see what he could do for us, as the ECU was definitely the main factor. He was able to source a manual transmission ECU for us and reflash it to the MX-5 Cup specs. Joe is a great guy to deal with. Not only does he know his stuff on these ECUs, but he was very accommodating on getting me a new ECU to use the following weekend. In addition to the more aggressive tune, Joe increased the rev limit and "unlocked" it so that the key was no longer required to be in the ignition. We plugged the new ECU in at the event the following weekend, took out the key and it started right up. However, as before.... we forgot that there was still a steering wheel lock, so the key was still needed for the time being! Ron ran the car across the parking lot and while it seemed a little more lively, it didn't become obvious until the first run of the course. As it turns out, the automatic ECU was really slowing the car down. The new, improved ECU felt like it gained us 30 horsepower!
Our second issue was that the car had a lot of understeer. Again, we had a much bigger front swaybar with our new Tri-:Point speedway style bar, and our spring rates had around the same spread that our CSP car did that also had some initial corner entry understeer. The fix here would be to increase the rear spring rates. We decided that at the same time we should take the opportunity to go with shorter springs. So, we ordered up a new set of Hypercoil 6" x 500lb springs. The only problem with this was that the shorter springs were only available in this spring rate with 60mm or 2.25" ID. Theoretically this shouldn't be a problem, but our adapter between the helper springs and the main springs were made for the 2.5" ID springs that we originally purchased. We therefore needed to grind down the adapter to fit. This would have been fairly easy at home with a grinder, but we were at the event site. It took awhile, but with a file in hand, we were able to to do the work required, and were able to lower the rear of the car an inch. While it still had more rake than we preferred, it was a step in the right direction, and looked much better.
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