Lets talk 4g63t

And dirt is a lot more forgiving for launches, which are the killer of DSM drivelines.  If you don't launch them, the stock gears can handle upwards of 500 ftlbs of torque though once you go over that the fatigue life is drastically reduces no matter what you do.  

Dogboxes are readily available for about $5000.  Well worth it when a built stock trans costs $2500 +. 

To me the 4g63T is a great engine(the 6 bolt version), however...there is little reason to use a 4G63T unless whatever car you are getting has one already or you are trying to to make 600+HP on a 4 cylinder...there are a ton of other 4 cylinders on the market that are lighter and more reliable for more moderate builds. I have owned several 4g63 cars(both NA and turbo) and they simply are not as reliable and trouble free as other 4 cylinder engines. As always when choosing a particular engine I suggest asking what your goals for that engine are...sometimes a 4g63 will check all those boxes...other times something like an ecoboost 2.3L is the better choice....or any number of other I4s, I6s, v6s or v8s(maybe even an I5 from time to time)

If you're talking about making more than 400HP, then any modern DI engine is out of the discussion.

Any EcoBoost or DI modern engine is severely cost prohibitive to operate above stock power levels.  Once you approach power levels that are ~15% higher than stock, you will run out of fuel without going lean.  The stock direct injectors are not large enough for that power level, and the high pressure fuel pump is also approaching the upper limits for fuel flow.  The only solution is to run an auxillary fuel system PFI, OR upgrade to extremely expensive aftermarket DI injectors (only a couple suppliers right now) and another very expensive HP fuel pump (only 1 supplier currently).  

Now that you're making more than 400HP on a 2.3L ecoboost you will start running into the failure modes of the base engine design. Bore distortion is inevitable, which will cause head sealing problems no matter what studs or gasket you throw at it.  You will need to fill the block to fix that. Once you overcome that issue, the structural integrity of the block will be a limitation; the 2.3L ecoboost block does not enough ribbing or thickness to withstand higher torque (higher cylinder pressure).  

That's not even talking about the tuning limitations of a factory ECU.  To do it right, you need a standalone that supports DI and VCT tuning.  Good luck tuning that, there aren't any base maps.  You will essentially be remapping ignition timing, injection timing, dual cam timing from scratch.  Short of having a professional engine dyno you will not get it to work.

So now you're looking at ~$5900 for a 2.3L crate engine, $2000-3000 for fueling solutions, $2000+ for the ford performance power pack (harness and ECU and calibration). That's almost $10,000.  Not counting a bigger turbo, intercooler, etc.  Sure a junkyard 2.3L might work, but I bet those aren't going for less than $2000 at this time.  You can build a DSM that will run 11s all day long for $10,000, an entire car.

There is a reason you see countless numbers of 4G63s in the single digits for 1/4 mile times and hardly any 4 cylinder ecoboost variants (there is only 1 mustang 2.3L under 10s I could find, and that is a 9.99s run), and other "old school" over engineered 90s engine designs like the 2JZ, SR20DET, etc.  The engines were over-engineered in a time before FEA, and tuning is very simple since it pre-dates OBDII and CAN bus integration.  

Source: myself, lead engine calibrator for Ford on the 2.3L ecoboost in the mustang and focus RS.

engiekev said:

And dirt is a lot more forgiving for launches, which are the killer of DSM drivelines.  If you don't launch them, the stock gears can handle upwards of 500 ftlbs of torque though once you go over that the fatigue life is drastically reduces no matter what you do.  

Dogboxes are readily available for about $5000.  Well worth it when a built stock trans costs $2500 +. 

That isn't the issue so much as it is things like getting a little air and landing in 3rd or 4th gear at max power.  The DSM transmissions could mostly handle that.

The Audi 01A is Audi's "weak" transmission and it will calmly shred gears if you bump the curbing on a track day at the 600hp level, for another example of the kind of shock loadings I am thinking of.