drmiller100

yeah, you're probably right. if it were a problem the straight 6's would have had vapor lock problems, overheat, and wander at high speed........ to be fair, the 6's have a fair amount of spare room through the tunnel the v8 jtr's don't.

the diagram shown is not a real car. even if it was, the CG is moving the same amount as the IC, so the RC will not be changed. However the CG going up will cause more weight to be transferred to the outside tire, reducing overall grip of the car. A lower CG is always better then a higher CG, except in dirt or snow racing, and maybe in rain if you can't change tire sizes.

there is some pretty cool stuff there. I'm kind of surprised the ram air you are running the hose you have feeding the air box is big enough. VERY smart idea though. On my 240 I campaigned on hill climbing, I let the hood come up about 3 inches to let air come out from under it. At rest it sat flat, but at speed it would come up against the latch. The roof of the car is a large wing with smooth un interupted air going over the top of it, LIFTING the car. If you ask the small airplane boys, they say a heavy frost causes crashes because the wings won't work with frost on them. If a fellow had a really crummy paint job, or maybe some magnetic stickers all cut up........... The other thing I believe in is SAFETY, so I am thinking about putting a LARGE WIDE brake light on the roof just in front of the rear hatch. Some might call is a roof mounted spoiler, but I'm more interested in the SAFETY aspects of it.

yeah, like that!!!!! So, back to the OP's question. One issue with a 240z and a V8 is getting under hood air out from under the car. A front splitter or air dam obviously helps that a bunch because it pushes air around the front of the car instead of through it and under it. This is also why v8z's can have problems cooling - the pressure inside the engine compartment can be almost as high as the pressure in front of the radiator. Another symptom you can test with is to leave the hood unlatched and drive the car at 60 mph. When you get it right, the hood stays down. If the hood comes up some, then obviously the pressure under the hood is obviously higher then the air above it. I looked pretty hard at putting vents into the inner fender walls of my 260, but eventually decided the strut tower support is already pretty flimsy, and drilling holes isn't going to help it. I am pretty well convinced if a race S30's didn't have inner fenders, and air was allowed to bleed out behind the front tires, the car would cool better and have more downforce. To maximize this, keep the fenders behind the front tires tucked tight towards the center of the car, and let there be a pretty good gap between the front tires and the fender behind the tire.

one way I think about it is to think about air flow speed. The tops of the fenders are often clear out in the windstream, like the front of the hood on a 240. So air is going really fast past it, uninterupted. Because of Bernoulli, this will be a relatively low pressure area, and creates lift. At the base of the windshield the air basically stacks up and quits moving. This becomes a high pressure area. When you put a splitter on the front of the car, you are trying to get most of the air to around the car, creating high speed areas on the sides of the car, which creates low pressure areas on the sides of the car where it really doesn't matter. Under the car gets weird. You are trying to get no air under the car, with a huge area. the ground actually "pumps" air out the back of the car. Those that try to build front diffusers are ambitious. The idea is to create smooth flow and cause air to go under the car and accelerate, causing a low pressure area. This is just like an airplane wing works, except you are using it in ground effect with the car as half the venturi and the ground as the other half. I tried it on 2 cars, and am pretty much convinced I would need a full scale windtunnel with moving floor to get it to work.

sorry, I don't know how I missed your earlier post. My bad - I thought the guy was till waiting for an answer.

so why are you guys throwing in all those bars going everywhere except where the suspension ties in???? Sorry, you are the expert, I'm new. I will quit asking questions and causing problems.

i'm pretty sure block hugger headers won't fit in a scarab. it seems like i read it in the JTR book, but can't find my copy at the moment.....

I've never had tires that were too big. What is it like???? I've never had too much grip either. how come you couldn't just lower tire pressures? When you raise the car on either or both ends, you lower the overall grip of the car. If you adjust the sway bar, it is possible to move grip from one end of the car to the other without losing overall grip in the car. Besides all that, raising the car up doesn't move the rollcenter of the suspension. If it does, you have much bigger problems.

on the jmortensen car, there is a down bar which goes from the top of the front strut tower to the passenger's feet. This provides a downward force in tension into the cage. This is exactly what I am talking about. It is relatively hard to do on the front of the z. When he tied the tops of the strut towers back to the dash, that was really cool, as it again ties loads from the top of the towers moving back and forth into the cage, which is hopefully pretty rigid. When building the brace across between the strut towers, heim joints sure improve stiffness. However, there is no need for a heim joint, and it might be more rigid to make it solid bars. i made mine removable by welding it to a plate sandwiched between the 3 bolts that hold the strut in. Remove 3 bolts on each strut tower, remove the cross brace, then reinstall the bolts to pull the engine. On the rear, the monkey car has a bar going from the top of the rear strut up into the roll bar. most of the rest of that cage is just extra weight. I shot from the hip on the loads to the tops of the suspensions. Fred Puhn suggests 5 G's is a design load, so with an 800 pound corner weight, we are only talking 4000 pounds. Per corner. But hey, cages are only put into cars for safety, never competitive advantage, right????

so you are saying you did all that work, and then are counting on seam welded joints to control the suspension??? Sure would be easy to run a brace from the top of the rear strut bar up into the back of the roll bar, directly opposite where the halo bar comes in. Sure would be easy to use substantial bars to tie the towers together across the body, and weld them in place, not just counting on heim joints to locate them. Sure would be easy to look at real loads coming into suspension points, then tie the roll cage into them, rather then pack a bunch of weight around cuz it looks cool. Sure would be easy to build bars connecting the cross member to the tops of the strut tower. What would be REALLY hard would be to build a bridge or ladder or sheer panel to tie the cross member weights and tops of the strut towers back into the cage in a vertical stress. With the stock cars, the inner fender wells are what carry the loads back. They carry them in sheer, but there are lots of bends and bad angles.

10,000 pounds per corner when you hit a good sized bump???

ok. Lets pretend the struts go up and down as the car turns this way and that, and hits bumps. Further, lets pretend the primary forces involved with these struts going up and down are that the tops of the strut towers go up and down. You have all those bars keeping the tops of the bars from going back and forth which is handy cuz they don't move anyway, but what keeps the tops fo the struts from flexing up and down???? 35 year old tackwelded sheetmetal, bars in bending, and happy thoughts.

so we are assuming the sway bar is used to tune steady state cornering, right? Sway bars pretty much suck for tuning transitions anyway, unless we are doing something like changing spring rates or roll centers and "fixing" results with swaybars. so, on steady state, we can assume the car is fully leaned over, suspension is leaning pretty much as much as it can. If in the middle of the corner we could run out and loosen up the swaybar links, you can see it will change over/under steer characteristics. likewise, if we could run out and physically change the sway bar and tighten the links, we could get the same results. Likewise, if we could change the contact points on the endlinks, same results.

if you can lower the car, why in the world would you run it any higher then you have to, unless you are drag racing????? Lowering the car doesn't usually change roll couple distribution very much.