I am quite pleased with my decision to purchase a DiabloSport Predator instead of SCT's Xcalibrator. After a month of comparing features, it came down to the Predator being more versatile and more inline with my current needs. Choosing between the two end-user tools all boils down to which features you want. I have a daily driven Mustang with an automatic transmission and I wanted to get a little more fun out of driving it. The Predator was a better match for me. I encourage you to make your own comparisons but here's what I found.
* They both come with semi-generic tunes.
* They both load the tune in a little over a minute.
* They both accept custom tunes from a vendor (via email or in person at a dyno tuner shop) so you can load it in your car.
* They both let you modify the tune (to some extent).
* They both cost around $350-$400 retail.
* The Predator has an LCD screen. The Xcalibrator has 4 flashing LEDs.
* The Predator lets you monitor parameters on screen in real-time and log the data for later analysis. The Xcalibrator can't. How do I know if my transmission temperature is getting hot during back to back runs at the track? How about during extended highway driving? How about stop and go city driving? I just plug in the Predator and watch the display. Can't watch the Predator screen while driving? Datalog the parameters and view them later.
* The Predator can read and clear OBDII codes on 96 Fords. The Xcalibrator can't.
* The Predator can hold one plus your factory stock tune. The Xcalibrator can hold three tunes plus your factory stock tune. This might be handy if you want to switch between tunes at the track. I haven't really heard of a clear case where having multiple tunes is necessary. If you have a tool that lets you make changes on the fly, why would you need to carry multiple tunes? It's not a concern in my case and I still see it as a gee-whiz feature.
* The Predator lets you tweak the tune from the handheld unit. The Xcalibrator lets you tweak the tune from your home computer but the Xtreme Tune software has been getting less than favorable reviews. It's obvious it was rushed. If you can get past that, this still means you need to lug a laptop computer with you if you want to make adjustments at the track. The Predator's interface is way better.
Update: SCT has released the Xcalibrator 2. From what I can tell, it's nothing like the original Xcalibrator and more like the Predator. They added data logging and an LCD screen and OBD-II reading and clearing capabilities. To modify the tune using the device, you need the vendor to create you a tune that is set up for on-device adjustments. If you want to modify the tune on your PC using the Xxtreme Tune software, you won't be able to modify that tune on the device. In short, there is a brick wall between on-device adjustments and PC-based adjustments.
There are differences in what parameters you can tweak. I recommend checking with each vendor for details but one key difference is that the Xcalibrator lets you remap the part-throttle and WOT shift points. The Predator can only do WOT shift points but gives you Torque Modulation settings. If you don't have an automatic transmission, this means nothing to you.
The Xcalibrator is advertised as having a "custom tune", which is nothing more than an off-the-shelf tune that was designed and tested to work on stock and mildly modified GTs, V6 & Mach 1s. It becomes "custom" when you order it because the vendor will tweak it to your specs (i.e., your gears, your MIL settings, your rev limits, etc.) You ask for it, they'll provide it. That makes it "custom". The Predator is labeled as having a generic tune, which is nothing more than an off-the-shelf tune that was designed and tested to work on stock and mildly modified GTs, V6 & Mach 1s. You customize it to your gears, your MILs, your rev limits, etc. The true custom tunes are done by tuners using dyno run data. Anything short of that is a semi-generic tune. Don't get confused by the marketing terms.
I think either tool is well worth the cost. Just decide which features are important to you. Aside from the gains in HP and torque, you save yourself $80 on a speedcal if you swap gears, $60 on MIL Eliminators if you get an off-road midpipe, $120 on a timing adjuster, $50-300 on a shift kit if you have an auto, and you can make adjustments to it all day long. You don't just install this mod and forget it.
If the end-user tool doesn't meet your needs, you can get a custom tune from a professional tuner and load it into your car using the Predator or the Xcalibrator. If you want to do in depth tuning yourself, there's always the professional level tools from both brands. DiabloSport Chipmaster Revolution (CMR) and the SCT Pro Racer Package (PRP). Those will let you do a thousand things more but will set you back around $700-$800. You will often hear SCT fans bring up the PRP when comparing the Predator with the Xcalibrator. Apples to apples and oranges to oranges please.
One big advantage of the Xcalibrator is that you can get the Pro Racers Package later for about $300. This will give you pro-level tuning capabilities. Anything that a professionaly tuner can do, you can do. The Predator does not have a single user pro-level package available.
There is a definite SOTP difference after loading the Performance Tune. The car moves a lot better under partial throttle, which is where I do 99% of my driving. It just goes! "Gobs of torque" is how some other Predator owners describe it. Most of the performance gain is in the entire torque and horsepower curves, not just the peaks.
My main objective in obtaining the Predator was to improve the shifting of the 4r70w transmission. I still wish the Predator was capable of adjusting the part-throttle shift points. That's where I do 99% of my driving. However, the Predator allows the user to adjust the Torque Modulation, WOT Shift Points, and Partial throttle and WOT Shift Firmness. When I first installed the Performance Tune, the changes to the auto trans parameters seemed minimal. I guess I was expecting a bit more. The Torque Modulation was set to stock (0%) for the 1-2, 2-3 and 3-4 shifts. I changed those to 100%, 100% and 0% respectively. The only choices were 0%, 50% and 100%. The setting of 100% equates to applying 100% of the torque during the shift. The stock setting of 0% means the timing is pulled back during the shift to make a soft and easy grandma-friendly shift.
The Shift Firmness is adjusted by increasing the line pressure. The changes applied by the default Performance Tune were also minimal in my amateur opinion. For the 1-2, 2-3 and 3-4 Part Throttle shifts, it was set to 20 psi, 10 psi and 4 psi. I tried out different settings and I think I've settled on 35 psi, 20 psi and 9 psi. I had it higher but I got tired of my head kicking back at each shift during daily driving and sometimes you can feel the shift kick in when you are barely stepping on the gas pedal. With the settings I have, the shifts definitely click off much quicker. No more 1 second granny shifts. I also increased the firmness on the WOT shifts. I have those at 180, 140 and 20 now. This is where the 2nd gear scratches come in. A setting of 120 is only halfway up on the scale. I kept the 3-4 shift on a low setting. I didn't want to stress the OD band. Besides, I am never at WOT when the 3-4 shift happens.
The WOT Shift Points are also adjustable. I bumped down the 1-2 Shift point from 5700 to 5600 RPM, and the 2-3 shift point from 5500 to 5400 RPM. I didn't really want to wind out 1st and 2nd while driving on public roads. After going to the track a few times, I set them back to the default. I may even raise them a bit.
I experimented with the EGR Switch setting. This lets you turn off the EGR. After reading about this some more, I decided to turn it back on. The feedback I got from message boards was that I could lose gas mileage with the EGR off. Some of what I read states the recirculated exhaust gas helps cool the combustion chamber, which prevents premature detonation. I can turn off the rear O2 sensors and the MIL indicator if I wanted to. For now, I left them alone.
The Predator allows you to adjust the WOT timing in the 2k-4k RPM and 4k-7k RPM bands. The displayed value is a percentage gain to be applied to the timing curve of the tune in use. It ranges from -40% to 10%. It's an increase or decrease of the base timing in the tune you are modifying. Spark advance is calculated dynamically and is based on RPM and LOAD. A 10% advance in the Predator means at any given point along the RPM vs LOAD curve, the resulting timing will be 10% more than what it would normally be. This only applies to the 2k-4k and 4k-7k RPM bands at WOT.
This is different from the traditional method of setting timing which uses a timing light or mechanical timing adjuster to set the base timing at idle. When you increased throttle, the timing would advance by a preset amount. We had no control over how much it advanced under throttle. The only control we had was the baseline idle RPM timing. The mechanical timing adjuster adds a bias to this fixed curve. You bump up the idle RPM timing by 5 degrees and it bumps the entire curve equally by 5 degrees. These are two different approaches to adjusting the timing and sometimes it's hard to seperate the two. The Predator applies a gain. The mechanical method applies a bias.
I started out at 4.0%, stayed at 6.0% for a long time, then slowly inched my way up to 8.0% for both RPM bands. I heard pinging at part throttle so I backed them off to 7.0%. I still heard occasional pinging so to be on the safe side, I set them to 5.0%. Then I remembered that the timing advance available through the Predator only applies to WOT timing. I have no control over part throttle timing, which is a good thing. As long as it doesn't ping at WOT, bump it up. I got the best results with both RPM bands maxed out at 10%.
The data logging is a cool feature. It lets you display "Live Data Groups" and watch the values change in front of your eyes. It can display parameters like RPM, Engine Load (%), Speed (mph), Intake Air Temp (deg F), Throttle Position (volts), Engine Coolant Temp (deg F), etc.
One major item I have monitored and will continue to monitor is the Transmission Fluid Temperature (TFT). The TFT is crucial to the life expectancy of the automatic transmission. So far, I haven't seen the TFT go over 200 during normal driving. If it ever does, a transmission fluid cooler will be high on my list. Without the Predator, I would need to install a dedicated transmission fluid sensor and gauge to monitor the TFT. Even if I did, I would not be able to log the data for later review.
Unfortunately, some of the items that you can select on the Predator aren't in the manual, and some of the items listed in the manual do not show up on the Predator. According to DiabloSport, an updated manual will soon be available. The next few pictures show graphs of data collected using the Predator.
The drop in timing right when I floored the pedal is the tip-in spark retard, and the spike after the 2-3 shift is due to the sudden decrease in load. I don't hear any pinging yet and I don't see a large timing retard events, so I will add advance again and record a few WOT runs.
I'm not sure if it was just me but it sounds like the car actually runs smoother too. The growl is still there when I punch it, but it is just smoother. Not as hoarse.
To connect the Predator to my home computer, I went to Staples and bought a standard serial cable with one male and one female DB 9 pin connectors on each end for $7.98 plus tax. Walmart had a universal AC adapter that puts out 3-12 vDC at 1000mA for $15.94 plus tax. These let me upload the log files to my PC to view them with the free log file viewer from DiabloSport. It also allows me to download updates to the Predator and accept a custom tune from a vendor.
Want to read more? Check out this thread on www.corral.net forums. Read the article. They have actual dyno results on a late model Mustang GT that show 15.5 HP and 16.5 Torque.
So, where do you go from here?
RUNNIN WITH THE DEVIL CUSTOM TUNING
After tweaking the part throttle shift firmness, after increasing the WOT shift firmness, after advancing the timing, I needed more. I wanted a better part throttle shift schedule. I wanted more timing advance. The next step was a mail-order custom tune. I chose to purchase custom tuning from Runnin' With The Devil (RWTD) based on their excellent customer feedback. $125 buys you unlimited tuning via mail-order. Major updates cost $25. Looking back, I should've bought the Predator from RWTD for $400. That includes the custom tuning. Live and learn.
Unless you have some off the wall combination, most mail order tuning shops will have a tried and tested tune for the combination of mods you have. Tuning is usually dead on. It's not really that complicated. If you drive into a tuning shop, they will typically start with a base tune out of a library, just like a mail-order tuning shop. If you send the results of a dyno run after receiving a mail-order tune, the tuner can make finer adjustments to get your tune even better. Sure it will take longer but it will generally cost you less. In shop tuning usually starts at $400.
The RWTD part throttle shift schedule makes better use the RPM range by delaying the upshifts. Unlike the factory part throttle shift schedule, the RWTD tune doesn't shift into the next gear as if you were letting off the gas pedal to cruise. The 1-2, 2-3 and 3-4 shifts hold out longer than normal to provide a better, more spirited shift schedule for light to medium acceleration. When cruising around a small parking lot, it will hold 1st gear and give you better control of your speed. If you have to accelerate quickly, you don't have to wait for a 2-1 downshift. By staying in 1st, you don't have to accelerate from below 1,000 RPM. In larger more open parking lots, it will holds 2nd where it would previously shift into 3rd. Being in slightly higher RPMs, you have more control of your speed and you don't have your left foot hovering between the brake and gas pedal, trying to decide which pedal to press. It also holds 3rd until you go above 40 MPH. I don't have to lock out OD to prevent the transmission from constantly shifting between 3rd and 4th. Under medium throttle, the gears also hold longer than stock and the car behaves more like it has a manual transmission. The shifts are firm and occur at 2500-3000 RPM. It sounds and feels more aggressive. Under heavy throttle, it shifts hard like it does at WOT. I have even barked the tires at the part throttle 1-2 shift. This used to happen only at the WOT 1-2 shift with the factory tune. The first time I ran on the track with the RWTD tune, the WOT 1-2 shift broke traction for what felt like a full second. Overall, the car feels more responsive because the gear changes occur at slightly higher RPMs without having to push hard on the throttle.
The RWTD tune downshifts earlier than the factory schedule. When you are in 4th/OD and decelerating, the factory tune assumes you will be slowing down to stop. It goes into coast mode and downshifts just as you come to a full stop. The RWTD tune downshifts at specific speeds as you are decelerating, not as you come to a stop. You actually get a slight engine braking effect. It also makes a huge difference in throttle response. As soon as you move your foot from the brake pedal to the gas pedal to accelerate, the car pulls immediately. With the factory tune, there is a slight delay while the EEC detects the throttle pedal input and commands the transmission to downshift. Sometimes, you have to settle with having to accelerate gently in 4th/OD from low RPMs, or forcing the transmission to downshift. The modified downshift schedule in the RWTD tune is better for daily city driving where the speed of traffic changes constantly.
Using the Predator to datalog the SPARKADV parameter, the default Performance Tune shows timing advance peaks at 21-22 degrees under heavy load. The Performance Tune at the maximum of 10% advance shows peaks at 24 degrees. The RWTD tune shows peaks of 26. If even more timing is needed, another 10% can be added using the Predator.
A dyno run of the first delivered RWTD tune showed an a/f ratio of 13.8:1. An adjustment was made and the next delivery of the tune showed xx.x (to be posted later).
1/8 MILE ET
I made about 20 runs on the 1/8th mile track across several visits with the Predator's Performance Tune. ETs were fairly consistent in the 9.3 to 9.4 range. When I set the WOT Timing to 10%, I was able to sneak in a couple of 9.2s and a couple of 9.1s on a good day. Yet most runs were still in the 9.3 range. With the RWTD tune, I made seven consecutive runs in the 9.1 range with one run at 9.09.
As of this update, we are not done tuning. I am still getting updated tunes from RWTD and I am still providing feedback. I can still use my Predator to make adjustments to suit my needs. Then I forward these settings to RWTD for incorporation into a new custom tune.
The downside: It takes RWTD about a month and half to respond to my requests. I don't know if this is normal but a friend of mine reports the same thing. We're lucky to hear back from RWTD in a month after posting a question. Another friend of mine went with a different professional tuner and is getting better response times. Out of my frustration, I came really close to dumping what I have and going with an Xcalibrator 2. That would allow me to edit the part throttle shift schedule on my own and not have to depend on RWTD and their month long response time. However, RWTD announced they will be transitioning to using SCT tools to I'm basically on hold on that issue.
$350.00 for the Predator
$125.00 for the RWTD Custom Tune
$ 15.94 for the power supply
$ 7.98 for the serial cable
(Did any of this help? Leave some comments in the guest book. Let me know you were here.)