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Re: coil over spring rates with ladder bars [Re: RustyM] #2499533
05/23/18 03:59 PM
05/23/18 03:59 PM
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Fulton County, PA
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CMcAllister Offline
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It's going to have a 150 or 170 spring on it, depending on how much energy you want to store in the springs. 150s will take a good shock to control the housing on the hit.

Need to know shock manufacturer and part number, or extended, compressed and installed lengths.

Does it have an adjustable shock mount so that ride height can be adjusted independent of shock installed length?

Why are the ladder bars wonky one side from the other? Is it sitting that crooked or not put together right? I see you said it was level. Was that eyeballed or measured?

Once it's back together, you'll have to neutral everything and start over with the corner weights.

Weight distribution has less to do with hooking (or not) and more to do with leaving and driving straight.


Last edited by CMcAllister; 05/23/18 04:02 PM.

If the results don't match the theory, change the theory.
Re: coil over spring rates with ladder bars [Re: RustyM] #2499534
05/23/18 04:00 PM
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thanks Floyd,I appreciate it.

Strange S5206 SINGLE ADJUSTABLE ( He thinks thats the shock, i have measurements coming)

Stroke 5.52″ / Extended 17.15″ / Compressed 11.64″

With .563″ Bump Rubber Installed
Stroke 4.957″ / Compressed 12.203″


Recommended Ride Height

13.875″ – 14.50″

Accepts 12″ x 2.5″ ID spring

Re: coil over spring rates with ladder bars [Re: CMcAllister] #2499536
05/23/18 04:08 PM
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Strange S5206 SINGLE ADJUSTABLE ( He thinks thats the shock, i have measurements coming)

Stroke 5.52″ / Extended 17.15″ / Compressed 11.64″

With .563″ Bump Rubber Installed
Stroke 4.957″ / Compressed 12.203″


Recommended Ride Height

13.875″ – 14.50″

Accepts 12″ x 2.5″ ID spring

Corner weigh details

LF-973 RF-809

LR-737 RR-845

LEFT- 50.7 %----1710

REAR- 47.0%----1582

CROSS- 45.9%---1546

TOTAL--3363 With driver and all fluids in car.

Front ladder bar points are in neutral position relative to front holes.
2.5 degrees down on front - drivers side.
O on passenger side.

Thanks Cm.

Re: coil over spring rates with ladder bars [Re: RustyM] #2499598
05/23/18 06:04 PM
05/23/18 06:04 PM
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I'd probably start with a 150, and run the shock at about 13.750 C-C at ride height. That shock should work if it's not worn out, but you'll have to crank it up some. I'd like to see a DA on it though.

Beyond that, I'd want to know what's going on with the bars. Way heavy on the RR if the driver's in the car.


If the results don't match the theory, change the theory.
Re: coil over spring rates with ladder bars [Re: CMcAllister] #2499614
05/23/18 06:48 PM
05/23/18 06:48 PM
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Quote"I'd like to see a DA on it though. " end quote.
Please forgive me- my mind isn't responding to "da" nomenclature today- probably just too dang tired.

I too am concerned as to why right to left weights are so far off.
weighed a 63 sport fury as well last night, 3700 lbs and weights all looked good - as expected.

There is nothing on the 65 mechanically or installed that explains to me why weights are so skewed unless ladder bars are really tweaked hard.

I looked at all adjustment points and same thread counts everywhere or, within one thread.

I guessing we need to loosen everything up , put in a 150 spring and re-weigh a nd see what shows up then???

please advise.

thanks so much.

Re: coil over spring rates with ladder bars [Re: RustyM] #2499638
05/23/18 07:41 PM
05/23/18 07:41 PM
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Bars varying 2 degrees from side to side is substantial. Something is bent, way out of adjustment or installed wrong. Thread count being close on all the adjustments kind of rules out the thing being adjusted that far out of whack. Is there an adjustment link provided in the bars?

DA = double adjustable shock.


If the results don't match the theory, change the theory.
Re: coil over spring rates with ladder bars [Re: CMcAllister] #2499650
05/23/18 08:13 PM
05/23/18 08:13 PM
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Romeo MI
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Is the rear end back braced.. if not I would
look there first to see if its twisted.. the
2.5 degrees is a fair amount and I'd look at
the axle housing
wave

Re: coil over spring rates with ladder bars [Re: RustyM] #2499727
05/23/18 11:08 PM
05/23/18 11:08 PM
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What are the front ladder bar bolt heights from the ground with driver in the car? By the weights shown it has a ton of preload on the RR, +100lbs. That could account for some or all of the ladder bar angle difference. I'm assuming the angle was measured with the driver. No way you need 150lb springs in my opinion. This video is almost your weight with 122lb springs/6 cylinder bars.
No problem with weight transfer.
Doug
https://www.facebook.com/debby.kersantywright/videos/10211668943904056/?t=7

Re: coil over spring rates with ladder bars [Re: dvw] #2499820
05/24/18 02:13 AM
05/24/18 02:13 AM
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That car leaves hard .
This car isn’t pulling a tire off at all at 675 hp, 5400 stall and built/ rollerized 727, 4:30 gears on a 29 x12.5 x15 tire.
Engine was stout on both chassis and engine dyno, really nice tq/ hp curve.

He was told tonight to just leave the coil overs “ loose “ ( not snug to coil pockets) to help get the spring/ shock compression needed.

Re: coil over spring rates with ladder bars [Re: MR_P_BODY] #2499826
05/24/18 02:33 AM
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Rear is braced .
He was pulling 1.48 60 foots, leaving wheels up but bent housing pretty bad.
Built a new housing with bracing and ladder bars , best was 1.46.
End of season ( he came in 3rd on points in spite of all the problems last year) and we put car in chassis dyno .
Then pulled engine and went to engine dyno ( engine builder unit for fast cars, extreamly conservative , heartbreaking to many) and pulled 675 hp .
This showed about 24 percent chassis loss.
We found frame bent on driver front and had put on chassis table to confirm and have fixed- confirmed and fixed.
Then added braces , new converter that better matched his dyno numbers ( old one was an old J converter that had been repaired/ reflashed many times and was flashing 4800)
Found driveshaft front yoke wasn’t long enough- only engaging trans output shaft 1 1/4 inches- new shaft.

First time out - car just won’t hook, finally gets another 1.46 60 ft.
Loses In semi finals running his same old dail in .

We take it to do some chassis tuning- I shoot video.
No separation - zero .
Spits the shaft - bad u joint clamps, they just broke.

We have studied the video intently , over and over - rear of car just isn’t budging at all- like it’s sitting in bars instead of coil overs.

At 12 lbs of air cold ( before burn out ) car isn’t hitting tire hard at all.
He was told this evening to leave a 1/4 slack on the springs when rear of car is hanging ( springs not snugged to cups)
None of the nuts were locked on ladder bar adjusters OR the alignment bar.

Was told the weights were so far off because tensions not exactly the same on the torsion bars.

I agree torsion bars need to be right and that setting preload on passenger rear will effect drivers side torsion bar .

But that’s way over a 100 lbs in front and back.

Re: coil over spring rates with ladder bars [Re: CMcAllister] #2499828
05/24/18 02:46 AM
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No on easy adjustment - just standard compitition engineering ladder bar kit.
We didn’t install it - just trying to help sort it out.

My guess is we need to take everything to slack , make sure torsion bars are correct with new springs and car at ride height and start from there.
I can confirm it’s a 12 inch spring at 200 per inch rate.
Shocks are 17.5 long extended and by leaving the springs loose1/4 to 1/2 ( not snug in the cup ) , putting the car back on the ground gives 14.5 length eyelet to eyelet .
So that’s 3 inch’s compression if starting with a loose spring on a shock with 5.45 stroke.
Strange single adjustable shocks- everything is new ( well, about 8 passes)
Slicks only have one season on them and they don’t race a dense schedule at all here in his class.

Car should be really close to 6.41 but runs 6.60 and has to dial in 6.73 ( 1/8 )

Has a points race next weekend so- hoping to get this sorted quickly.

Re: coil over spring rates with ladder bars [Re: RustyM] #2499974
05/24/18 01:52 PM
05/24/18 01:52 PM
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I have never hear of people running 200# springs
on a car in that weight range.. with the 1/4"
of space your just trying to make the spring
lighter in weight(cant happen)in my car(lighter)
I use 90# springs.. you just want them to hold
up the body.. the stiffer they are the harder
to get transfer(no movement in the rear)
wave

Re: coil over spring rates with ladder bars [Re: RustyM] #2511550
06/22/18 12:00 AM
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Hey Guys: wanted to update folks and say proper a proper “ Thank you” as best I can from here.

The update : We put the 150lbs coils in the rear, 4 cornered the car and ended up with 23 lbs heavy on passenger rear and drivers weight distributed pretty evenly over car/ drivers side .

Car went lazer straight , best 60 ft ( 1.46 ) and ran it all night.
Ran best time - 6.58 ( 1/8) and ran it consistently .

Still not where it should be, what’s desired realistically but, man, what a beautiful change in the car.

Thank you to everyone here- literally , just a huge thanks !!
Best community I have ever had the pleasure of associating with- just top drawer!

Still little movement/ weight transfer.
Bump stops were too tight so we opened that up to get some movement there.
I still think rear springs are a little to heavy , i’m Thinking the car will like 130lbs.
Ladder bars are nuetral - parallel with ground / middle Hole, May need to drop them down one but would like to see video of the hit and 60 ft first .
He should be able to get my video this weekend .
Car ended up at 3340 lbs with driver/ helmet / jacket in car, fuel cell full.

Most of the “ imbalance on the 4 corner weights was in the torsion bars - they were fighting each other.
Main thing right now- car leaves/ runs straight thus safer for everyone , it’s quicker as well and it’s not beating the car up .

Thank you all very, very much.
Any new advice is welcome of course!!

Blessings of Grace and Peace
Rusty

Re: coil over spring rates with ladder bars [Re: RustyM] #2511638
06/22/18 09:30 AM
06/22/18 09:30 AM
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Congrats on your improvements. Race ready mine is 3340lbs also. It uses 125lb springs. We've run it as heavy as 3420 to make index. The last 3 passes in 4200-4500 D/A; 1.308, 1.308, 1.303 60ft. Lighten up those springs. That'll help it pitch rotate.
Doug

Re: coil over spring rates with ladder bars [Re: RustyM] #2511658
06/22/18 11:01 AM
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Thanks dvw.
What length shock are you using if you don’t mind me asking?

Re: coil over spring rates with ladder bars [Re: RustyM] #2511670
06/22/18 11:26 AM
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He had already bought the 150lbs springs by the last time we posted DVW, I think the jump from 200 to 125 was a little worrisome.
I rode in the car yesterday and, it pulls hard, its just a transfer
rotation issue imho.
Car IS very stiff.
put a floor jack under lower control arm near ball joint- whole front end come up- both sides.
Grab frame connector at rear, whole side comes up etc

So, chassis is pretty stiff and well balanced now, car finally going straight, true for him.

First run on new set up- things happened fast enough he hit the rev limiter at 6800 before completing shift.

If you dont mind me asking- you know about what hp your running- would like to know where cars are comparable to help in estimating changes.
He is at 675 at the moment, likely make a little more with a new carb, some tuning etc.

Thanks so much.

Re: coil over spring rates with ladder bars [Re: RustyM] #2511678
06/22/18 11:41 AM
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correction- 3345lbs

LF- 920 RF-832

LR- 787 RR- 806

LEFT 51.0% 1707

REAR 47.5% 1593

CROSS 48.4% 1619

TOTAL 3345

He has seen a 1.46 60 before, but never consistently, it was dead nut 1.46 last time out, really bad air down here right now in 95 degree temps.

Yesterday we went from 88 degrees and 84 % humidity to 97 degrees with 37% humidity , then down to 82 degrees with 48 % humidity- just gotta love it- grin.

We are just starting ( beginning ) to get our heads wrapped around weather/altitude density etc.
I read a couple fairly short engineering papers on timing and air/water density last night- we have so much more access to data today than 40 years ago - its amazing.

Re: coil over spring rates with ladder bars [Re: RustyM] #2511680
06/22/18 11:42 AM
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A Big thank you to Dom as well for help in tuning and trying to understand carbs and weather.
Thanks Dom.

Re: coil over spring rates with ladder bars [Re: RustyM] #2511699
06/22/18 12:18 PM
06/22/18 12:18 PM
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Shocks are 17"/11" travel. Never dynoed. My bet is 900+. Trust me we've chased traction as we run 10.5's. It is now VERY good. Learn from my mistakes.
Doug

Re: coil over spring rates with ladder bars [Re: RustyM] #2511709
06/22/18 12:38 PM
06/22/18 12:38 PM
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"a correction CM: He does have lighter spring tension torsion bars , RUNS TRAVEL LIMITERS."

I see a problem there, friend had a 427 Vega, very hard to hook the tires, no rotation. He sold the car and the first thing new owner did was remove cable limiters off the front a-arms. First time out with no other changes carried the front wheel 1-2 ft and would hook on snott and picked up 2 tenths.
Original friend wanted the "pro stock look", didn't like the tires hanging down on launch.

Last edited by cudaman1969; 06/22/18 12:50 PM.
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