Forum: HoseHeads Sprint Car General Forum (go)
Moderators: dirtonly  /  dmantx  /  hosehead

Tell me if I am wrong, I am just a crazy sprint car owner. People are now trying to get more flex in frames to get cars to handle better. If you bolt engine in solid in rear motor mount and front mount, the frame is trying to flex thru the motor. If you are in a crash, this may happen quite alot. I saw a 360 break every bolt hole out in rear of block, and others have broke front bolt holes in block. This can only put alot of stress on your $50.000 engine block. Kng makes a front engine mount that pivits in center, also there are now front mounts with rubber bushings. These were made to help chassis flex, but would they not be valuable to keep stres out of engine block. Also I have seen rear motor plates bolted in with 5/16 bolts in the 3/8 holes.

I believe you are right with putting stress on engine with the flexing of the chassis, i know most guys only put the four bolts in the motorplate to engine block and don't use the top two through the frame to the block so you have the flex of the aluminum motorplate to account for some chassis flexing, also saves from buying 2 more Ti bolts! ha, also know of quiet a few teams that have been running those rubber deals in the front motorplates for years and also know alot of people drill out the holes in the front motorplate few sizes bigger to allow movement, and even seen a few that only put one bolt in the front motorplate.

I know of people who don't put a bolt in the left side of the front motorplate to get more flex.Like Ozzie said above. A lot of midgets don't even have a mount on the left front side for a motor plate and seen a few that doesn't even have a front motor at all.

on our midget, we bolt the rear of the motor to the plate with nothing thru the frame and in the front, we use a small radius rod and a panhard clamp to bolt to the frame and the front of the block and leave it a little loose. it gives enough support to let the motor flex a little without flexing the (magnesium) rear plate too much. we tried it without the front mount and it just shook the hell out of the plate just idling in the pits. this car went thru a wicked set of flips that bent the frame pretty bad but the motor and mounts came thru it with no damage.

"Awww hell just don't put any bolts in it....Bet she will flex then.....LOL...J/K"

i think KKR tried that when k swindell drove their midget.....um, yeah....the motor fell out.

Im not 100% sure how chassis flex will aid my car in handeling, afterall dont we want the suspention components to react as designed,understood all chassis and componets will have a greatter or lesser tolerance value, is this a phantom mystery chssis builders are willing not to discuss completly? sure chassis flex and positions of bars will make a heck of a differance in safety, BUT, I have yet to hear the winning car was a softy that didnt fall apart? 90% of the engine torque and weight is achieved at the rear plate IMO, agreed when a engine is bolted firmly in place by front and rear the front of the "greenhouse " has got to be pretty dam rigid, I can understand the torsion tubes recieving a bit of deflection , Honestly the longer span of downtube cars are more flexable than the later non downtube , My discussions with a couple chassis builders I noticed them bending the downtubes to accomidate those big ass valvecovers ect, Q: making a couple adjacent bends with opposite conjunction of force, hmm , wouldnt that promote less flex? I must be the only one that sees it that way?

racers are vultures of the next best thing. its kinda humorous, we all know it is, its never the driver!, theres ALWAYS a mysterious mechanical thing that could have made them a winner . If the winning car on raceday had a 2 lb pile of dogshit on the hood everybody would have it the next week, (I dont own that quote) and my black lab would be a very buisy hound.... " step right up, get your fresh fast dogshit right here!!"