Trailing arm reinforcements? And wheel studs Options

[mb911]

I am at the point where I will be sand blasting the suspension and doing the 5 lug conversion. Do the trailing arms flex that much that they need reinforcement for a street car? And what length wheel stud should I use for the 5 lug conversion?

[shoguneagle]

There use to be a lot of information concerning this "problem" going back to Brad Robert's and the old 914club.com. It ultimately boils down to the same question unsolved involving whether to "stress strengthen" or to leave the rear trailing arms stock. Same question back then and it is still here today.

It has been mentioned it depends on whether the car is for 'street" or for "track"; what about a combination?

I have built my car over the years for both the track, street, autoX, and the desert. You have to remember I lived in Arizona for a time. The following is what I did to may car to meet the goals of the above:
seam welded planned split lines in front and in the rear; welded the cross sheetmetal to the outer sheetmetal of the fenders as well as tying them to the shock suspension consoles which were also seam welded; outer rear mounting consoles and inner ears reinforced; inner stress kit installed; outer Brad Mayeur stress kit installed; 911 front suspension and brakes with 18mm torque bars/Koni Red adjustable shocks; rear set with 911 brakes, Koni Red Adjustable and Adjustable perches and 150# springs; four corners set on Elephant Racing Brass suspension parts; front 21mm and rear stock sway bars; front tires 205/45-17 and rears 235/35-17, all rims CupII; 3.2 1987 Carrera engine with moronic injection; probably more since I have enjoyed building and finding out answers such as this thread covers.

All the above rhetoric boils down to the car having some flex for give when under heavy load; thus, as Mark Henry says, "this area more of an issue with body mount in the suspension console area" and whether the stock can take it from the modern tire improvements, modifications, purpose, and knowledge. I built from the ideas of others and as they changed over time; I always felt that certain points had to be stress and others did not. One thing I did not seam weld is the car crunch zones since it was to be run on the street. The same reasoning goes into the rear suspension arms where I wanted flex both on the street and on the track; I would much rather have a point of forgiveness at extreme loads rather than have it react differently when reinforced.

I have to agree with the ones who do not stress the rear arms especially for the street because these cars do need some flex but not where it is a "flexie flyer" either on the track or on the street.

These are my thoughts and now I can go back into my "old age dreamworld" working on the car.