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Author Topic:   feedback on 13" rear springs
Raz_900
Dirt Forum Champ
Total posts: 635
posted June 23, 2005 08:20 PM  
I'll try not to make this too long. After doing some measuring and reading some posts on here, I switched to 13" rear springs from 11". When I measured the 11s, they only gave about 3"-3.5" of travel before coilbind.

I've run 225, 200 and 175s in the back with the RR always 25 less than the LR. It seemed to work best with the 200 and 175 on a big 1/2 mile (.588 in the middle), med. banked dry slick track. With the 225 and 200 combo, it felt really unsettled after the weight transferred and the car was in the end of 1 entering 2. (which was probably the 200 binding up on the RR where the 175 coils where thinner and gave a little more travel)

After switching to the 13s (same 200 and 175 as I'd been running) it feels much more stable and predictable in the corners. All I'd done was install the taller springs and add/remove spacers to get the ride heights about the same except the rear is now 1" higher. What was a loose car at the end of one now progresses into a tight in the middle car after 5 laps. With rainouts, I've only gotten 2 races in, but it's a night/day difference.

On Sat., my g/f pulled me a 1, so I got to start on the pole of my heat. Led the whole thing beating 2 former track champs. Then, after pulling a d@mn 10 on the invert, got t-boned on the start and limped to a 9th place finish (23 cars). Tues. was a special event, started 3rd in my heat, lead laps 1-6 then the push let last years 2nd place car get by me so I finished 2nd. Got caught up in an early wreck and was put to the back and finished 14th.

So... just some food for thought. It's definitely faster and more predictable through the turns, especially the first 5 laps before it gets tight. Once I get it tweaked to get rid of the tight middle, lookout. SCP springs are still $25 if they have any left in what you're looking for.

[This message has been edited by Raz_900 (edited June 23, 2005).]

racer17j
Dirt Forum Champ
Total posts: 5390
posted June 23, 2005 08:38 PM  
Well, before it was so loose coming off, there really wasn't much going forward. Now, it's alot more controllable coming off, so I guess you could say there's more forward bite.

If you're bottoming out the 11s, which if the roll decreased, there's a good chance you are, the taller springs should help. Mine's all in stock location with a Ford 9". To change springs, I now have to disconnect the shock on the side I want to change, jack it up, put the frame on jackstands, then jack up on the opposite side to tweak the rear end in the car and get the spring out. PIA, but worth it.

Haven't checked the lower arm angle after putting the new springs in. Before, it was 1-2 degrees uphill from the rear to the frame. I probably should check and see how much it change.

3dracer
Dirt Full Roller

Total posts: 32
posted June 24, 2005 02:21 PM  
We have about 7 or 8 degrees of lower angle with our 13's. All stock location on a 9 in. Like the car alot better after we put the 13's in, seems easier to drive and alot more consistant. Also had o bump up on the spring rates a little to take some roll out of it.

racer17j
Dirt Forum Champ
Total posts: 5390
posted June 24, 2005 03:57 PM  
I run the 13's on a metric, with a 10 bolt, and love them. I run a 225 on the left and a 100 on the right. The car rolls a little on the rr coming out, but pulls like crazy. The set up I run loves a dry slick right on the bottom, best car I ever drove.
Rick

Blind Barney
Dirt Maniac

Total posts: 120
posted June 26, 2005 10:01 PM  
haracer, what do you run for front springs?

hsracer158
Dirt Full Roller

Total posts: 33
posted June 28, 2005 08:34 PM  
1100 rf 900 lf and big front sway

napa115
Dirt Roller

Total posts: 23
posted June 29, 2005 09:04 PM  
hey hsracer,
dow does that car turn in the middle? we have the same bite coming off but cant get it to turn in the middle. i have all the same springs as you except 150 rr. car has a ton of movement but just too slow in the middle. what are your scale numbers and shocks at each corner? how much stagger?
we run a flat half mile real slick by feature time. any info will help

hsracer158
Dirt Full Roller

Total posts: 33
posted July 05, 2005 02:22 PM  
Napa,
Scale #'s total weight is with me in it 3110, and I weigh 210.
Rear% is about 47
Left % is about 52
Cross % is about 56
I have to go and get set up sheet to give you exact wheel weights.
I run bilstein shocks all around from speedway, and I run a rear sway bar. It handles great in the middle, and comes off very strong. Comes off of 2 better because our track 3 and 4 are a little tighter than 1 and 2, so what I do in 3 and 4 is diamond the corner and it seems to be very good. we run a 3/8 med banked track. We have been experimenting with the rr spring, and so far the 100 seems to get us the best bite

    

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