Originally Posted by jz78817
there are limits to what you can get from a naturally aspirated engine of a given displacement. Coyote is pretty much limited to about 400 lbf-ft without forced induction. making bigger hp numbers means they'd have to push the torque peak higher in the RPM band, at the cost of low- and mid-range performance.
For making more than 400ft-lbf crank torque from the Coyote with no nitrous or forced induction, it can be done.
The Coyote Aluminator XS crate engine is mass produced by FRPP to produce 500BHP at the crank.
You are correct that to pull bigger BHP, you have to shift the torque curve higher in the RPM bandwidth and sacrifice midrange and lowrange RPMs.
That is the nature of the beast and the Aluminator XS does just than by using the Cobra Jet intake manifold with its shorter intake runner lengths.
However, the XS does not give up too much low and mid range BHP. Surprisingly, it holds onto its torque even at 2000RPM with over 250ft-lbf
The XS is very streetable for an 8000RPM redline engine; this is largely due to the fact that the Cobra Jet manifold has the exact same intake runner lengths as the Boss 302 intake manifold.
By the harmonics of the pressure waves coursing through the intake runners, that means the Cobra Jet intake and Boss intake are tuned to provide their best BHP at around the RPM bandwidths, which is higher than the stock Coyote intake, but still very streetable without a massive sacrifice to low RPM daily driving.
As for breaking 400ft-lbf crank torque, the XS easily does it. Late Model Resto put an XS on the dyno and measured 382ft-lbf at ~5500 RPM at the rear wheels, so assuming 15% drivetrain loss at 5th gear, the XS is producing nearly 450ft-lbf torque at the crank.