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Author Topic:   Adjustable Lowering Block
RangeRover
Dirt Maniac

Total posts: 174
posted November 19, 2002 12:34 PM
With leaf springs, is it helpful to use one of those adjustable lowering blocks? You know, the ones that allow you to lead or trail that side of the rear end. Which side would be better, left or right? I have a 1.5" block and was thinking of putting it on the left with no lowering on the right and adjusting the heights with shackles. Has anyone used a similar set up?

c21
Dirt Freak

Total posts: 346
posted November 19, 2002 12:57 PM
I would start with adjustable block on the right and a 1" (or so) on the left.

trying to compensate for 1.5" of lowering block with a shackle would require a shackle 3 or more inches longer than the other. it would probably require a pinion shim (to compensate for the different leafspring angles) and would do some strange (though not nessecarily bad) things to your antisquat and rear roll center vertical location. .... one other effect(a positive one), however, might be throttle-tightness (more un-wrap on left leaf on-throttle, lengthening the left side).

c21

[This message has been edited by c21 (edited November 21, 2002).]

CAGEMAN
Dirt Full Roller

Total posts: 30
posted November 22, 2002 12:35 AM
It depends on what the car is doing and what arch springs you have,with big arches when compressed the wheel will move back and when arched (like the left rear) the wheel moves forward. If you have no arch in your spring at rest and when you go into the corner the rr will move forward and thats why there are springs with little or no arch and there are springs with like 5-7 inches of arch, you have to figure your wheel travel and simulate the wheel moving forward or bakward and for whatever track you will race on will dictate what to do for adjusting lead in the axle. Like if it pushes bad on entry or if it is way loose on entry, adjusting the lead can help or hurt it. I like big arch springs, I run three inch lowering blocks, but it is also in a big dodge and it is low to the ground. You have to set up the front suspension first to determine your rears ride height, then make the car a half to one inch higher in the rear.
c21, are you from Estevan?

c21
Dirt Freak

Total posts: 346
posted November 25, 2002 02:04 PM
Cageman, I am from many places though not Estevan.

I think I was mistaken in thinking that the lowering block (on one side only in this case) would have any impact of significance in so far as how much the spring would wrap or unwrap.
I'm thinking however that dissimilar arches less arch on the rt) and lowering block on the left only would be a way to create a lot of roll oversteer (to compinsate for RR lead). Which could make for a lot of forward bite ... Just hold on tight if you hit any big bumps in the track (roll steer can happen anywhere with trailing arms/leafsprings at dissimilar angles).

c21


CAGEMAN
Dirt Full Roller

Total posts: 30
posted November 26, 2002 07:31 PM
I know of a guy that races and his number is c21 and he always posts with that name, thats why I asked.

[This message has been edited by CAGEMAN (edited November 26, 2002).]

c21
Dirt Freak

Total posts: 346
posted November 27, 2002 10:19 AM
no harm in ask'n cageman.

I've been posting as c21 for years, don't recall bumping into my "twin" (came across a c23 on the RPM net last year or the one before).

If I were to be more specific about where I race or who I am I think I would feel less comfortable about occasionally sharing "gray area" technology.

c21

CAGEMAN
Dirt Full Roller

Total posts: 30
posted November 29, 2002 02:17 PM
I hear ya cluckin' big chicken!

RangeRover
Dirt Maniac

Total posts: 174
posted December 02, 2002 09:18 AM
I'm working on a '77 Nova and haven't messed with leaf springs in a while. I bought Landrum springs and new spring pads to weld on when setting pinion angle on the new Ford 9" from a Lincoln Versailles. The left side spring has more arch (and rate) than the right side, so should I use a 2" lowering block on the left and the 1.5" adjustable lowering block on the right. I'm trying to make the new car as good as possible right out of the box. What can you camaro and nova guys suggest?

c21
Dirt Freak

Total posts: 346
posted December 02, 2002 11:33 AM
Sounds like a reasonable place to start. I'd put it on the scales before you put it on the track. Keep in mind that it is normal to have a higher frame height on the right than left (.5" to 1" or so higher) so the extra arch on the Left (are we talking mixing dirt and asphalt springs?) may require more of a block to get your proper ride heights .... but you got to get it on the scales before you know anything.

On a side note, depending on how banked your track is (or more specifally isn't) this set up may give you a lot of roll oversteer.

c21

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