Pector55

Has anyone else added this mod and then hit a dyno? I added a Jay Green cam and PnP heads with mine and my top end is much stronger. It no longer drops off like it did prior. My switch is set to activate the short runners at 4800 but I see no visible changes in the dyno. I don't know if it's taken out with the smoothing or if it's not opening and I'm stuck in long runner. I dyno'd prior to my mods but it was at a different dyno. I can only really compare the power curve between the two. However, I add that my buddy dyno'd exactly both days so I can use him as a bit of a ref: dyno 1 (before my mods) dyno 2 Me 374/401 381/399 Buddy 376/405 330/360 - The power curve was the same but the dyno was roughly 12% lower. Low - Very similar results: This leads me to theorize that the long runners possibly helped offset any loss from the larger cam. New dyno starts at 3k RPM / 195 hp - by 4k RPM, it appears to be slightly ahead of old dyno Old dyno starts at 3k RPM / 205 hp - by 4k RPM, it appears to be slightly lower than new dyno Mid - Very similar results: New dyno from 4.3K to 5K both are around 380 ft lbs and by 5250 I'm down to 375. Old dyno from 4.3K to 5K both are around 380 ft lbs and by 5250 I'm down to 375. High - New setup shines On new dyno I peak HP at around 5200 RPM (381 HP) and at 6200 (my current shift) I am still in the same area - On old dyno I peak HP at around 5200 RPM (374 HP) and at 6100 RPM I had dropped to 340 HP) Now I'm planning to hit the track on Wed to see which set of numbers are closer to the truth. Either way, the power curves are a useful tool and I'm happy with how my car is performing right now.

Do you have a table in your Predator under Closed Loop Enable called ECT Rear? If so, that's the coolant temp in which the rear O2 sensors are enabled to participate in closed loop. If you set that to an unattainable temp then the rear O2's will remain enabled but will not actually bother you with codes. I don't own a Predator so I don't know if you have access to this. I would expect that you do.

Have you attempted to advance the exhaust on the low RPMs to get some of that bottom end back as well?

I pull the fuse for quick part throttle tuning. I can reset the fuel trims and log STFT's, then see how much VE is off in certain cells. It takes about twice to get fuel trims dialed in really close for closed loop.

Thanks a lot Mike! I wonder if that's why guys with 5.7's have stock dyno numbers that vary so much. I've seen them quoted at 315 to 340. I know that you can expect that between a Mustang and DynoJet and I know corrections can be different on DynoJets even but still.. that is quite the range.

This is old but Mike, do you know a way in which to set the car to dyno mode using HP Tuners?