Would there be any mpg gain if stiff motor mounts were installed. It would help get a bit more HP to the wheels so I assume it would help get a timy increase in mpg. I don't think it would be woth the extra rattles.
2008 EPA adjusted:
Distance traveled by bicycle in 2007= 1,830ish miles
Average commute speed=25mph (yes, that's in a car)
Do stiffer motor mounts really increase whp? That's a pretty cool idea, I think my main thing against doing it would be the pain in the *** to install all of the mounts, it might be something for Matt to do when he does his swap, but he'd have nothing to compare it to. I figure if I'm making 92 chp (crank hp) and 80 whp now, and I put on stiffer mounts and made 92 chp and 84 whp, I'd save some mpg from not having to strain the car as much.
Sounds like a good DIY, something I'd do, haha, got any links that talk about making your own mounts? I remember long ago the damn stuff for rabbit mounts using caulk or some suchness. Do you have any idea also about how much does this increase the whp compared to before as a percentage wise thing?
Stiffer mounts just help prevent lost motion in the engine rocking back. You can buy aftermarket mounts with a polyurethane of various durometer ratings, or [like on my daily driver], you can see if Prothane makes an insert kit for your car. I got mine [inserts for all four mounts] for $27. Engine vibrations are transmitted to the cabin a lot more now, but it doesn't bother me.
For cars that aren't supported by the aftermarket, you can make your own mounts. The cheapest way to do this is to go to Advance Auto and purchase some 3M Window Weld - it comes in an aluminum caulk tube and is thick black goop that is mostly polyurethane. Get a caulk gun and fill all the voids on your mounts - I have done this to two cars, one for performance, and one because the mounts were shot and this is the cheapest way to repair them. You can go a little better than this and purchase some mix-it-yourself polyurethane from McMaster-Carr [you can pick your durometer], but it's harder to make because this is more runny than the 3M and you'll have to build 'dams' to hold the urethane in the mounts during curing.