Upon pulling out of the carport I realized the Camaro was not going to be as docile as I hoped when I spec’ed out that mild 112/118 duration cam! It was very torquey and surged when attempting to accelerate and torque braked hard as soon as you let off the gas. This was noticeable even in third and fourth gear. This made it almost impossible to log useful data in traffic as the only way to drive it without the car violently bucking around was “flat out”. My first test drive also involved topping off the gas tank and I found out that I had a leak somewhere high up on my tank (it was not leaking when not full but leaked when full). This wouldn’t be that big of a deal except I still didn’t have a reliable reading from my 68 Camaro’s 40-year-old gas gauge sending unit so I was guessing about how much fuel it had at any moment—making it difficult to fill it up three quarters of the way.
I put the following on the www.pro-touring.com forum board hoping for some help:
When taking off in first, i find it very difficult to not spin the tires. If you are going balls out on a track it might be OK until you have to come off the gas–but in street traffic when taking off at a stop light and then trying to feather back off the gas so as not to rear end the vehicle in front of you, the car surges forward, then if you let off the gas it jerks or bucks very hard due to the torque braking. I have the Commander 950 software running and am looking at my throttle position sensor when i am doing this, and i have a relatively light foot (TPS is 1 closed and 172 for WOT, i am applying values of ~10 when this is happenning). I have found for the street the only way to drive it is to let traffic leave me to create a gap, then take off aggressively in first, then go to second almost immediately, then go to third and essentially allow the car to idle along in traffic (idle is 850 RPM). In third, the ammount of torque on tap is diminished enough relative to the load that i can come on and off the gas (again, i’m talking 3-5% of WOT) with controllable surges rather than violent bucking. Traffic around me still think i’m an idiot because the car bucks with even the slightest progressive addition of gas (i looked at my datalogs and i’m talking TPS values of around 5–roughly 2-3% of WOT).
There were a lot of thoughtful responses, and three things I could implement pretty quickly: double checking throttle linkage and spring tension, moving the idle up higher in the RPM band, and setting the shocks softer. I disconnected the spring from the throttle linage but didn’t see any other way to make it more progressive in the short term. I also set the DSE-sourced Koni adjustable shocks at one click out from full soft in the front (they had been set on one click from full hard) and to ½ turn from full soft in the rear. Then I raised the idle RPM to 950 in the Holley Commander 950 software and adjusted the throttle return set screw to get the idle correct so the idle air control solenoid was in control of the idle. I figured I would deal with the gas tank leak later since it only leaked with a full tank of gas. Upon taking it for a test ride, it was still very rough but seemed somewhat improved mainly by the throttle spring and idle speed changes. Unfortunately upon adjusting the front suspension I was now bottoming out on bumps at speed. Although I had the 2001 Trans Am as a back-up, I decided to race the Camaro on Sunday and see from there what to do next. Unfortunately I was travelling on the mainland for work and United Airlines stranded me there on July 12th, the night before the race I had been waiting 3 months for! The only good news was that there was another SCCA Solo II race two weeks later, so I wouldn’t have to wait too long to test out my modifications.