For tuning, Shawn actually spent most of his keyboard time modding various tables that just monitored what the engine did. There are numerous torque tables that will dial back the output of the engine if they detect more power than stock! It is important to alter these properly as some of their output looks like things like knock detection retard. When the tables are edited properly, the engine is free to make more power while the OEM safeguards remain functional. This is why we cannot stress the importance of going to a tuner like Church that has a full understanding of how the ECU’s multiple functions work. Shawn explained to us some of the many mistakes that less knowledgeable tuners make and what the implications are. One of them is turning off or greatly limiting the knock detection retard, instead of editing the torque tables.
Interestingly, in covering the parts of the tuning that we understand, Shawn’s changes were pretty mild. The engine was running pretty lean, which Shawn says is typical for an LT1 with an MSD Atomic intake. After correcting the AFR across the board, Shawn experimented with adding timing. From prior experience, he was pretty sure that it was not going to help but he did anyway. With more timing, our motor made less power and we started to get some knock count. We ended up going back to the stock ignition map. So our tuned ECU is actually more conservative than stock!
Here you can see the tuning gains on Church’s Dynapack dyno. You can see 24 more hp just from tuning! Our LT1 belted out an impressive 486 whp and 481 lb/ft of torque. Shawn said that this is one of the most powerful bolt-on LT1’s that he has tuned to date and it is a pretty strong testimony to the effectiveness of the Holly Performance family of parts that our car has. Typically an LT1 only makes a little over 400hp on this dyno. Our results are ab0ut 80 hp! That is impressive for a naturally aspirated engine. Shawn also said this is about 20-30 more hp than what he typically sees from a stock LS7! We obtained our goal of beating the LS7 with an engine that provides a wider powerband and much better fuel economy due to direct injection.
On the MotoIQ heartbreaking Superflow dyno, the results are not so impressive but you can see the car’s history here from bone stock, to the addition of the Hooker Blackheart exhaust, to the Intech intake, and finally the headers and intake manifold. Curiously, our last step felt like it woke the car up the most but it didn’t have the biggest single part gain on our dyno. Shawn told us our last round of mods will typically give 40-50 more hp on his dyno and that is what we thought our last round of mods felt like. On to LS Feast!
