[IamIan]

If an ICE throws away around ~70% of fuel energy .. Just ~8% of that ~70% would be about ~5% of total original fuel energy .. such a ~35% ICE+TEG combination is a ~16% increase over such a ~30% ICE alone .. Such a ~16% increase to a ~50MPG driver would mean ~58MPG , same ~16% increase to a ~80MPG driver would mean ~92MPG, etc .. Although I myself suspect around ~10% increase over ICE alone is probably a more reasonable/realistic limit of DIY feasible for such waste heat recovery.