sorry if this post is in the wrong forum...

i've tryed my best google skills, but havent been able to find much information on "direct mounting" the 13b. I hope i am using the correct term, but to clairify, I mean mounting the 13b to the chassis without the use of rubber or any other vibration absorbtion material. I know rotaries vibrate much less than recip engines, but how much less? has anyone tried or heard of anyone directly mounting the motor to a chassis with just welds, bolts and brackets? my comfort is not much of an issue, im just worried about the vibrations ripping the car (or engine) apart. (car is a 1989 240sx)

 

We have solid mounts on two FC race cars. It really doesn't make the whole car hum with the engine rpm's but we don't have all the stuff on the cars that can vibrate loose like interiors or dash etc. If it isn't a daily driver it shouldn't be a big deal.

I made solid mounts to replace the pancake looking rubber/metal discs. I started with some 1 1/2" square stock and covered the open ends to make little cubes. I then drilled a hole all the way through them and got a grade 8 bolt that will go all the way through the aluminum mount, the steel cube and the subframe. Make sure you make them the right thickness within about an 1/8" to keep the drive line in phase.

 

the car is guttet with no interior, so i reckon we'll be ok with the direct mount then. i may try and make something modular so that i can easily slip 2 hockey pucks in between the motor and chassis if the steel casues too many problems. thanks for the help, do you have any netlinks to thoes race cars you spoke of? i'd love to check them out...