[vex]

Well, here it is. One of the most asked questions on any rotary forum: “How can I get a turbo on to my NA RX7?” Sure there are other derivatives of it, but for the most part it all comes back to wanting to turbo a Naturally Aspirated 13B. The long and short of it is that you really shouldn’t put a turbo on an NA keg unless you want a few specific things and don’t mind a few other things.

For instance you should know up front that simply turbo charging any naturally aspirating engine is no small feat. You have to plan out ahead of time what you want to do and how much you’re willing to spend. If money is no object to you or you have amazing expertise or ability to fully custom mount a turbo than more power to you. As it stands however you may wish to consider the predominately easier and cheaper route of swapping in a similar series turbo version. That means swapping not only in the drivetrain (engine, transmission, differential, half shafts, drive shaft) but also the harness and ECU.

Only desiring to have a hi-compression turbo charged engine eat up part of the full cost when compared to another project, IE: If given the choice between turbo charging an NA engine or swapping NA rotors into a turbo keg, you will be hard pressed to beat the price of just tearing the engine down and swapping in the rotors—all else being equal. If those are your only reasons for wanting to turbo charge the NA keg, I highly suggest you turn away now and not do it. You will be sorely disappointed and unable to re-coup your monetary loses which have been put into doing it.

Keeping this in mind however, there are a few reasons to put a turbo on an NA engine. One of the rather large benefits of keeping the 13B 6PI engine and mounting a turbo to it is for the combined tuning possibilities of the 6PI on the S4 as well as the VDI on the S5. This adds another dimension to the possibilities of power and tuning, but more importantly provides additional ability for controlling the torque curve (and hence for this write up will focus predominately on the torque curve).

Being able to modify the torque curve is the crux of this project. You will not see greater gains from the port size as you would from a similarly ported turbo engine, you will not see greater reliability from a similarly modified turbo engine. You will see more tune ability in the effective range of the 6PI and VDI. This means you will have the possibility of more low end grunt, and acceleration. This however can be compensated in other similar turbo charged engines by advanced tuning and correctly sized and plumbed turbo.

If you have read the above and still desire to turbo your naturally aspirated engine be prepared to spend between $7,000.00 to upwards of over $10,000.00. This is of course assuming you purchase everything new. Only when you begin to receive parts that are significantly under retail does the proposition for turbo charging the 13B 6PI become monetarily feasible.