trashline

lol I agree, my main goal was for a drag setup but when I went to a SAAC event last year I changed my entire setup to a track car!!

Norm Peterson

The main effect is not as obvious as the weight removed from the front end. It's a rearward shift in the relative front and rear suspension roll stiffnesses. Load tends to go where there is more resistance to it, less to where there isn't as much.

What happens is that more of the engine torque reaction is carried rearward and helps "re-plant" the RR tire (that goes a bit light as the pinion gear tries to climb up the ring gear). This happens because by removing the front sta-bar you've made the rear suspension relatively more resistant to the roll that the engine torque reaction causes, and that attracts more load through the RR spring and shock.


Incidentally, the Shelby mod raises the front roll center, and it's the higher roll center height that tends to reduce the amount of roll. There are good things about low roll centers, but like just about everything in the world of suspensions there are compromises that you have to make.

I don't know precisely why the Shelby mod might not be the hot tip for a primarily strip weapon (that sees only occasional street duty), but it does seem that more often than not a mod that's good for the dragstrip is not good for the road course or autocross lot - and vice-versa. I see the nose starting out a little lower (minor CG height effect), a camber thrust issue if the LF comes up but the RF does not (straight-line stability), and maybe the spring's motion ratio changes enough to have a small effect.



I think this discussion got side-tracked by differing interpretations of the term "street/strip". Some folks see "street first, with occasional semi-serious nights at the strip" while others see a dragstrip car that can be reasonably driven on the street even though it may not ever see a whole lot of street miles.


Norm

trashline

I have a kit at home ( Im at work) that relocates the spring perch 1" towards the outside of the car. The general thinking seems to be it will help this, but I have not heard anything about it yet. Im going to hopefully get this modification done soon and I hope it produces good results.

68EFIvert

I have the details of my suspension listed in my sig. Basically it is coil overs at all 4 corners.

supraman408

hey everyone. thanks for contributing with pictures and what your running.
after some research ive decided on my suspension set up.
560 1" drop coil springs
4.5 mid eye 1" drop leaf springs
Opentracker upper and lower street control arms
roller spring perches
1 1/8" front sway bar
steering kit with roller idler arm
KYB front shocks and Grab a Track rear shocks (recommended by John Dinkel of opentracker)

will probably do the shelby drop with the big rim small rim combo to give that raised rear lowered front look. suggestions are welcome.

tx65coupe

That looks sweet! I kind of like it better in the first picture with the rake. Either way it looks great.

tx65coupe

I have 600 1 inch front lowering springs and new stock 4 leaf rear springs with KYB gas adjust shocks. I also have slightly longer shackles to raise the rear a bit. I have 235 60 15 rear tires and 215 60 15 front tires. My car has about a 2-3 degree rake to it using an anglemometer. I think thats what its called.

The comment was made before about 620 front springs and stock rear springs being mismatched. I can say that 600 front springs and new stock rear springs is decently matched. The rear end of my car is really stiff. It would ride like a tank with 4.5 or 5 leaf in the rear.

I just got my car running again recently. I will get some pictures of it in the next couple of days.

trashline

IMO i wouldnt waste the money on the street arms I would get the full roller setup, or build them yourself. Im surprised John recommended KYB's. I never used them but from what im being told they arnt that great. but probably good for a street car? which is why the recommendation probably. but then why the large sway bar? Id think 1" would be up to snuff on a street car. The roller idler will help with street driving, as it eases the manual steering.

What about strut rods? remember no poly bushings

Norm Peterson

About matching front and rear springs . . .

For ride quality, front and rear springs are chosen on the basis of suspension frequencies, wheelbase, and some assumed range of speeds that the car will be driven in. The idea is to have the front end and the rear end each complete one full cycle of compression/extension/compression back to static ride height at the same time. That minimizes front to back head-toss, which most people find objectionable (think old pickup truck with nothing in the bed going down a bad road).

It is possible that slightly/somewhat stiffer front springs won't upset this flat ride balance very badly, especially for an enthusiast driver who may tend to drive a little faster than average and is less bothered by NVH. And as long as the shocks are in good condition, the movement "quiets down" more rapidly than it would in a car with 100,000 mile old base-suspension OE or aftermarket "bargain" shocks.

As far as handling is concerned, stiffer front springs have both an understeer effect and an oversteer effect. Most peoples' driving isn't nearly hard enough for much difference to show up and the overall change may go unnoticed, or at most the car may feel vaguely more stable.


Norm

Deviousfred

Coming in late here.

Global West Tubular Upper with their drop
620 springs cut down 1 1/2 coils
5 1/2 HD rear leaf springs with a mid-eye