I've noticed in looking both at the fueleconomy.gov site and also the real world MPG database that the difference in fuel economy between the manual HCH and the CVT is almost nonexistant. It's only about 2.5 MPG versus the first generation CVT and only 1.5 MPG versus the second generation CVT. This stands in stark contrats to the massively higher FE of the Insight Manual vs Insight CVT.

Why is the impact of the manual tranmission so different in these cases. Aren't the cars both using similar Honda IMA technology? This just seems really odd as generally manuals are a great deal more efficient than automatics, granted CVT is apparently a major improvement over previous automatic transmissions.

With a difference of only 1-2 MPG it almost seems pointless putting up with the inconvenience of a manual, unless one really likes to drive a stick. Of course this is now a moot point since newer HCHs don't come in manual anyway. I'm still curious if anyone has any explanation for the performance of the CVT and manual gen 1 HCH being so similar, as well as if there is any thing really advantageous about going with the manual over the CVT.

Automatics have come a long way. With the new Saab 9-3 the manual and the auto have the exact same mileage. With a CVT the computer can slow the ICE down by playing with the transmission. You can't do that with a manual.

-Dave

It's all about the gearing... in a manual you can force the highest gear in at will.... in a CVT you cannot. The CVT will hunt for the "right" gear for the job at hand... but not neccessarily the best FE gear ratio. If you could lock the CVT into it's highest gear ratio, you would probably be able to achieve closer results to the manual. Even so, I think the manual high gear ratio is larger than the highest ratio of the CVT. Advantage, manual.

Didn't the Insight CVT qualify for tax credits whereas the MT didn't because the MT uses lean burn?

If I remember correctly the MT is lean burn and the CVT is not, Insight wise. Don't know anything about tax credits......

Well, people are saying that the advantage goes to the manual, which is true, but looking at the real world MPG the advantage is almost non-existant. I'm just confused by why the Insight Manual has such higher gas mileage, whereas the Civic Hybrid Manual barely eeks out a win versus the CVT. Maybe lean burn is the real source of the Insight Manual's advantage and not so much the transmission itself?

Surely lean burn has something to do with it but I don't think that it is the biggest factor. The engine is actually completely different in the Insight CVT vs the MT. According to InsightCentral the CVT's compression ratio is 10.3 to 1 while the MT is at 10.8 to 1. The higher compression the better FE wise. I'm pretty sure that the MT is geared up quite a bit taller as well.

The MT's lead is seriously diminished with the HCH but the lead still goes to the MT if only by a hair according to our database. Summer is not giving the gen 2 HCH as big of a boost as I expected. I don't think the gen 2 is going to catch the Prius or the gen 1 MT.