TheLion
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- #1,801
I was given the opportunity to test one of ATM's new production units by Dave at ATM at cost. The Levels Gen 3 did pretty good on cooling, but I've noticed the car had some lag and it would periodically hesitate which I never experienced prior to installing the Levels (however the stock unit would heat soak so quickly the car would constantly be pulling power with anything beyond 2nd gear, sometimes even in the middle of 2nd gear on a hot day, it was no good even on the factory calibration). So while the Levels introduced some lag and periodic hesitation and low rpm / light throttle, it was still a big improvement over stock. The car was still making good power over all.Maybe I missed it in one of your above posts but why the change in intercooler?
Or your just trying a different shape one to see how performance compares.
The ATM does seem to have a deeper core were the main airflow is, at the bottom, at least from the pics.
I also noticed however the top end was extremely flat with the Levels inter cooler and -CJA FP Calibration, this was especially apparent when switching to the FP Calibration (which for a while I thought it was just the limits of the Calibration). While the intake manifold (cold side) temps were great, the inter cooler seemed to be causing the turbo to run out of steam at the top end. It was very noticeable when the rest of the power and torque band was so strong.
I've suspected the inter cooler and possibly the calibration, may be responsible for the weak top end for a while, but wasn't sure which one or possibly both were the culprits. According to FP the only difference between -CJA and -CJB is the fix in the mid range, so that means the drop off in power at the top end was being caused by the inter cooler, which I'll explain below.
Once I had it dynoed I confirmed what was very obviously felt in real world driving. Torque would rapidly drop off starting at 5800 RPM and by 6000 RPM power dropped from 300 hp at the wheels to 250 hp and stayed at 250 hp until fuel cutoff at 6800. I believe at the upper RPM range the turbo wasn't able to maintain pressure at the flow rates required from 5800 to 6500 RPM, causing it to run outside of it's efficiency range.
Once you move outside of the efficiency island of the turbo your heat output increases significantly on the compressor side as well as the back pressure (and hence you get heat buildup in the exhaust) on the exhaust side. This would certainly cause catalyst temps to increase significantly and consequently the PCM was protecting the cat by pulling power and dumping fuel to cool things off. Both the shop owner I had the car dyno'd at and Mike Goodwin af FP confirmed that as they both told me that same thing.
That power drop off is not due to mechanical limits of the turbo / cams, timing, fuel or air intake rates, it's clear from the dyno the PCM is limiting power for some reason at the top end. While the rest of the power band (save for the funky glitch between 5000-5300 that gets fixed in -CJB) was great. I changed two variables at once just last Saturday after the dyno (installed the ATM inter cooler and flashed to the -CJB revision), which seems to have corrected that issue at the top end and also the flat feeling in the mid-range between 5000-5300 RPM.
The car seems to pull much better at the top end and there's almost no detectable fade, at least compared to before. You'll drop some power as your reach 6500, but not nearly as much as my dyno showed. Of course the flat spot in the mid range is also gone due to the calibration. The lag is also gone now as well (mostly due to the inter cooler).
I originally had wanted to purchase the ATM inter cooler when I first started upgrading but they were closing up shop right at that time so I was not able to get one before they dried up. There's more to the ATM inter cooler's design than just it's stepped core shape making the best use of air flow. It also uses rounded bars instead of traditional flat bars. They act like a velocity stack and allow for 15% better air flow compared to the flat bars (80% efficiency vs. 95%). The rounded bars are internal as well as at the ambient face (outside), so you get high flow rates externally which increases cooling capacity, and lower pressure drop internally without altering fin density (which reduces cooling by reducing both surface area and dwell time).
Flat bars add inefficiency to flow rates internally and externally without adding to the cooling capacity. Fin density determines dwell time and heat transfer (by surface area) primarily, but the flat bars decrease efficiency without any positive cooling benefits by creating additonal restriction where the air is not passing the cooling fins be inhibiting their entry into the cooling vains (where the fins are stacked).
The end tanks on the ATM appear to also be minimized for as low of a volume as possible without inhibiting air flow to the various parts of the core where the end tanks of the levels are quite large (more appropriate for a big turbo application). Adding volume to the end tanks only adds lag without any other benefit, it also adds turbulence which creates additional pressure drop and cooling inefficiencies. So those 3 differences when combined make for a reasonable increase in overall performance. Buy once, cry once!
Simply put, the combination of one of the best inter coolers on the market from ATM and the -CJB revision of the Ford Performance Calibration is impressive and the car now runs with the responsiveness of an NA engine but with all the benefits of a FI engine.
It pulls nice and smooth throughout the entire RPM range now without the wall at the top by 5800 RPM and the lag I had wit the Levels Gen 3 is gone. I think I've found the warranty friendly (and long service life of the car) trifecta for the ecoboost mustang owners who want the safest and most reliable route to tap into power potential the car has to offer (without stepping up to a V8).
1. FP Calibration (-CJB revision)
2. ATM inter cooler
3. 3.73 Torsen diff (or 3.55 Torsend diff for auto)
You can't get much better than that without going to more involved and warranty voiding after market modifications (like big turbo's, built bottom ends, shop tunes) at which point you mine as well buy a super charged coyote for $10k from Midway Mustang and swap it in which can put out 670 HP on pump gas all day long without a hitch.
Externally, the ATM occupies 880 in^3 while the levels occupies 980 in^3, not a huge difference, but internally the could not be more differently designed.
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