Sorry to leave you hanging. I have been working alot and taking care of our new addition (baby boy).
I dont really have any suggestions other than those offered in the thread I think you are referring to. Today the Turnpike was empty and no-one bothered me in the far right lane (3-lanes each direction). So I drove super slow 50MPH and when rollcoastering hills hit as low as 45MPH.
So If I am reading between your lines correctly you've only slowed down a bit further :?: No higher tire psi, cardboard radiator block or hot air intake modification :?:
You should be able to maintain MPG by _slightly_ accelerating back down the hills to regain some of the lost speed up. Just watch the MPG indicator and keep it HIGH :!: And when traffic allows, increase the intensity of the rollercoaster ride to further increase MPG without any more time spent :!: (slow a tad bit more on the uphills and regain it bcak on the downside.)
Not sure how the Fonz spells it it but yes 'Exactimundo' Roller coastering letting my overall speed drop to 45MPH (only possible when not rush hour). Then recovering the momentum on the downside. I must stress that if you do this during rush hour were I live someone will shoot you.
No radiator block and no hot air mod. Is it ok to use the radiator block this time of the year? (I live 10 klicks north of philly). Tires are still at 45PSI.
BTW: I am really hesitant to inflate the tires beyond the max specified on the sidewall. I know this is safer in the winter than summer but still scares me a bit. I have noticed that my anti-lock brakes are much more sensitive when 'pumped-up' becuase of the reduced size of the contact patch. Has anyone else noticed hair trigger anti-lock function with 'pumped-up' tires?
Well I live a couple hunderd lattitudinal line kliks _south_ of Philly and mine's already in (cardboard radiator block). With A/C off and maximum MPG driving I've kept it in to the low 80F without problems. In _cold_ (60F or less) using the AC for dehumidification has also been OK. Drive like a bat out of H--- with it in even in the 60's F and you may have some overheat damage.
If you don't feel that your Insight is safe at the higher PSI (and yes it handles differently) then don't do it. And I'll not mention it again. (just ignore me if I forget).