Vgt compounds vs t4 non-vgt single turbo with REAL data. S364.5/73/91 vs 73mm LP with stock HP. More turbo data! YES!!! My favorite.
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We had the guys down from One Stop Truck Shop LLC today. They brought a 6.4 with s364.5, s2 cam, fass fuel system, and EZ Lynk tuning. We will be comparing it to our shop truck with basically the exact same setup... except turbos. I will break down the pluses and minuses of each setup. Just spouting off peak numbers really does not do a good job of describing the 2 setups.
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1st graph is a loaded dyno run. This would simulate a boost launch or hard run at the track.
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s364.5
633hp
1224tq
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73mm LP with stock HP
621hp
1253tq
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But lets break it down a little more. The s364.5 made 8hp more starting at about 2800rpms and carried to redline where it was making about 11hp more.
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The stock compounds brought peak tq on about 300-400rpms sooner. The s364.5 was completely useless under 2000rpms. It would just smoke and downshift so we had to start it much later in the rpms. So it is hard to describe how much more power it makes under 2000rpms. That is why I love doing "non-loaded 2000rpms pulls".
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Lets take a look at the 2nd graph. This is a good way to test spool up difference between 2 turbos and represent max hp under less load like blowing through 1st and 2nd gear without the tq converter locked in higher gears. Or rolling into the throttle at lower rpms in OD. You can see the compounds come right to life with ease... where the s364.5 really struggles. The compounds come to life about 500-600rpms quicker.
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At 2500rpms the compounds make almost 600 ft/lbs of tq more... if you could get the s364.5 to not downshift at 1500rpms that gap would be even greater. The compounds make more peak HP, but even under light load the s364.5 makes a little more top end power starting at 3200rpms.
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Now the boost/ebp numbers that I know everyone is wondering about.
At 2000rpms
s364.5 7psi boost and 9psi ebp
compounds 31psi boost and 45psi ebp
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At 2500rpms
s364.5 34psi boost and 38ebp
compounds 40psi boost and 48ebp
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At 3000rpms
s364.5 39psi boost and 52ebp
compounds 42psi boost and 66ebp
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at 3500rpms
s364.5 34psi boost and 60 ebp
Compounds 44psi boost and 73 ebp
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So the s364.5 obviously spooled much slower, WAY SLOWER. Those who say they spool just like stock are CRAZY... but the s364.5 was able to make more top power with less boost and less ebp. So it is "more efficient" and "safer" for top end power.
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If you like lugging the motor and cruising around 1500-2500rpms then it is no contest and will enjoy upwards of 600 more ft/lbs of tq. 73/stock Compounds are for you. But with a higher stall converter and some tuning to keep the rpms up and easier to downshift... then the s364.5 is gonna make more top end power efficiently... 8-10hp.
Neither truck has a working EGT gauge... wish I had the data to compare. Sorry.
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NOTE: The weird dip on the loaded s364.5 graph seems to be a common issue we see with some peoples EZ Lynk tuning. It happened on every run but did not affect any of the peak numbers or data we posted. It was after peak tq and before peak hp. We were not working on the tunes for that truck... just wanted dyno numbers.