If I had to guess the fuel lines and other misc components are the same. Probably a different wiring harness at the engine level to accommodate the additional sensors and a different ECU.
Another downside to the FFV is you are forced to a 5k OCI to keep your warranty (10k on the non-FFV). Also, no TRD supercharger allowed on the FFV.
I would like to know why the performance is different if running E10 only. There are more than a few threads on here with people who have to reset often to clear the alcohol percentage (even on E10) and who claim the difference in driving a non-FFV and a FFV is night and day. Several claim the already poor fuel mileage is even worse on the FFV.
I wonder if relaxation of EPA guidelines will change this in the future?
Well, IT IS what IT IS. And, just like a lot of other vehicle decisions the Big 3 will let the buyer tinker with, Toyota has made this decision for you, like it or not.
What you have to remember is that of the total production of 5.7L Tundras with FFV, only a relative few have reported problems. This is NOT a guaranteed outcome; Toyota couldn't stay in the FFV business if it were. Reviews of any product or service are like that; you're only going to hear about the exceptions...the bad news. But, the silver lining of your dark cloud is...if everyone in middle America is being forced to buy 5.7L Tundras with FFV, and if the majority of owners are having problems, then Toyota is going to work out the bugs a LOT faster in order to clear the clamor and unhappiness out of their dealerships. Maybe you need to wait a year of so to buy a Tundra.
OCI? Others have told you the pros and cons. Personally, I have always thought Toyota's service intervals were ultra-conservative, and BS. GM cars with oil-minders typically calculate OCI, depending on driver habits, at 10-15K with NO restriction, to the best of my knowledge, on types of oil (mineral vs. synthetic) or fuels. You have to decide what you want to do about the warranty, but the courts decided a long time ago that dealer service was not necessary to maintain your warranty, and I don't think that's changed. If they want to duck the maintenance claim over an OCI even they can't decide on (Is it 5K, or is it 10K, with FFV?), they are probably going serve you up a ROS anyway.
Turbo on an FFV? If Toyota says no, you won't have a warranty. In fact, they probably don't want ANY turbos (except for maybe one they spec'd and sold) on ANY of their products. I would be surprised if ANYONE having any engine with an add-on turbo wasn't going to get hassled or denied on a warranty claim.
Poorer mileage? There is no reason for this to be true for E10. Thanks to stupid politicians, that probably is the only grade of regular gasoline you can buy. Where is the reference point? Keep in mind you are quoting anecdotal evidence collected haphazardly and unscientifically; there is no consensus even among TT members what mileage these trucks should get, because the trucks, and the drivers, are all different. If there is any loss of mileage when grades above E10 are used, then that is not too surprising, and likely has to do with the BTU/lb content of ethanol versus the gasoline it displaced. Back in the old days before electronic engine controls, the old hooptie went a bit further on premium than it did on regular, but cost analysis showed it didn't pay to buy premium if the car didn't "knock" on regular.
EPA relaxing their standards? Maybe "The Donald" will help us out there, but I sure wouldn't want to wait on buying a new truck until that happens...not quite as bad as holding your breath, but right up there.
