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Post by Dave Schultz on Apr 20, 2011 9:12:22 GMT -5
In Bradenton, Dallas' car wasn't launching right. When we got it home, we found the Aldan Eagle shocks were beat. We put on a set of new QA1 16" single adjustable coil-overs. The Aldan's were sent back to be rebuilt, and the tech called me to say that we were bottoming the shit out the shocks with hard launches with a bad ride-height -- and destroying the shafts, valves and other internal components of the shocks. He suggested that the starting point for 16" coil-overs is to set the ride height (using the spring spanders) to 14.5" bolt-hole to bolt hole of shock. Then to put little plastic twist ties on the shaft just above the shock body, so the body can push it up the shaft on launches it can stay up and mark how far the shock compressed. He said you want about an inch short of bottoming out. The first couple of passes Dallas feels like he had an inch left before bottoming out. However when we got the car home -- the shocks appear to have bottomed out either on the last pass -- or the trailer ride home. I don't think the trailer ride home can come close to compressing a rear shock like a launch can -- and I have air ride in the trailer. We did have the front end of the car tied down initially, but removed the bolts used to tie it down and put in rubber bump stops for the last pass. The reason we did that is that the car will pull the front wheels off the ground about average for a 9.75 car that does a 1.34 60' -- but it doesn't carry it for more than a couple of feet. It doesn't come down hard because it doesn't get real high -- but it comes down quick. Removing the bolts that tied down the front and replacing with the rubber stops, and setting the front 3-way shocks to lowest position helped slightly -- but just slightly. The car doesn't bounce when it comes down and it doesn't get squirrelly. I was in the stands taking sequence photos of the launch from the side. The rear shocks are set to 5 and 6. I need to adjust from bottoming out the shocks and I also feel like the car will do better if it carries the front wheels at least past the tree. I might need a converter change to obtain this -- as frankly the PTC converter I have in the car was made for when the car was a transbrake car launching at 3800 RPM -- and not 2500 RPM off the footbrake. I'm assuming that I need to lower the spanders maybe another 1/2" for a 15" bolt hole to bolt hole, and maybe add another click or two to keep the shocks from bottoming out. Does this sound about right? Attachments:
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fugly
Full Member
Posts: 103
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Post by fugly on Apr 20, 2011 23:24:29 GMT -5
I don't think so.....it's a 4 link car- raise the instant center some
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Post by Dave Schultz on Apr 21, 2011 8:07:36 GMT -5
I'll post a side view of the 4-link mounting points later
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Post by Dave Schultz on Apr 21, 2011 17:03:11 GMT -5
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fugly
Full Member
Posts: 103
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Post by fugly on Apr 21, 2011 17:22:27 GMT -5
Can't tell anything from that- need a side view with the rear loaded ( on the ground or stands) -need to be able to see bars in relation to frame
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Post by Dave Schultz on Apr 21, 2011 17:56:29 GMT -5
That won't happen until next week as the undercoating on the front part of the underside is being scraped and sanded off -- and the underside painted to make cleaning easier.
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Post by poppaj on Apr 21, 2011 19:19:49 GMT -5
What weight springs are you using?
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Post by Dave Schultz on Apr 22, 2011 7:38:33 GMT -5
I had Aldan Eagles 658, and the come with 300 pounds. www.aldaneagle.com/shocks.html I replaced the shocks with QA1 DS501 www.summitracing.com/parts/HAL-DS501/ I've noticed that the extended length on the QA1 is 17 vs 16.5" on the Aldans. The ride height of the shocks are 14.5 bolt hole to bolt hole, based on the shock guy telling be I had 16" shocks. I'm wondering if I might should have the ride height set at 15.5 since the QA1s are 17" and not the 16" Aldan was talking about. |
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Post by texoutsider on Apr 22, 2011 8:16:26 GMT -5
Are you lost now or looking to be?
If the car is banging the shocks, first I would increase the shock setting ...then maybe re think the spring rate...THEN start adjusting the 4 link. Ya know, in all these years that I have been building cars for you........you have never asked me these questions or anything about setups...nor have you "tested" after the fact at a track where I could possibly have any input on these car's setups...........Instead you ask everyone except me...........I don't quite understand Dave......you will spend thousands of dollars to have me construct the cars and then let every tom dick and harry give you input on how to set them up later...........I think that all of them after a couple of tweaks went right down the pike and worked. Instead you show pictures on your boards to all and ask questions............Sir, in most cases you have to take everything in consideration, not just one part...........the car must be evaluated overall......from the ride height to the link/ladder setups, shock settings, spring rate and tire pressure........all relative to the weight/hp of the car and it's transmission/clutch/convertor.........ya just about have to be there and see it and then do it.........opinions are like assholes............all different..........the way to get the most out of any combination is test, test, test and more testing..............make changes, more changes and more changes......keep records of all and evaluate..........Most likely one or two passes with me in the seat could eliiminate most of your problems with setups..........or maybe the guy that put the cars together and has been doing it for over 40 years now .........oh well........remember that red Dodge that we set up for you?.............As I recall it went one entire season and you did not change a frickin thing................
Give em hell Dave.........rant is over
Mark
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Post by Dave Schultz on Apr 22, 2011 9:00:53 GMT -5
Mark -- Damon and I were talking about the 4-link settings on the phone, and I posted the photos of the mounting points there based on a phone conversation we had. When the car is finished with the underside detail, he's coming down and we'll look at where the instant center is.
Before then, I just wanted to be able to make sure what the ride height starting point should be when changing the shocks that had different extended and compressed lengths, as I felt like that should be the first place to start.
I post the questions here for a couple of reasons, one is in the hope experienced chassis people like you will help by posting your opinion, two so others might also gain benefit of that expertise when they have the same situation, and three for visitors to learn who the experts are to take their cars to based on their expertise. I'll bet my posts in the past have introduced you to customers like GTS Dave and Trannyman -- to name just two -- based on their interpretation of your posts and my always giving Texas Thunder credit for building my cars.
On this particular car, I ran it one year before windowing the motor -- and then it sat for four or five years. Now that we have the motor sorted out -- we're trying to tune the chassis and looking at each and every run it makes. It isn't far off and 60's in the low 1.30s -- but we want to make it the best we can. In Bradenton we learned it just didn't squat right on launching -- and found the bottomed out shock. For Atlanta, it is bringing the wheels up a reasonable height (not looking for Scotty Jiles type of wheelstands -- but simply for good weigh distribution) but it isn't carrying the wheels. Just up then down. We found the front 3-way shocks were set to maximum stiffness, and loosen them a little, and it looks a little better -- but most likely the Instant center is too far forward, and we intend to try a minor adjustment to move it back a little and try before we get to Ennis. However I still want to get my shocks adjusted to the right ride height, and that was my question.
Other issues I need to deal with in that car is the torque converter. Frankly, it is still the PTC 8" steel stator that was set up for transbrake launches at 3800. I intend to deal with that by getting the proper one for the car.
So in a nut shell -- I am trying to learn more about the car and I do see that small single adjustments are made and evaluate their effectiveness. Each car has a log book and each change is logged, and every time slip dissected.
I post photos here as a photo is worth a thousand words, and have been hoping that you would look at them and give me your opinion.
You are right, the red car was set up right and needed virtually no changes but shock adjustments. It lifted the front to a reasonable weight transfer height and carried it until the 2nd gear shift. On the black car -- it too was set up well 7 years ago -- but a lot of water has gone under the bridge since then and it needs tweaking. Right now, I want to learn the proper starting point to get the new shocks with a slightly different extended and compressed height set to where they're not ruined like the Aldans were, and asking what the hole to hole ride height should be set to for the QA1 shocks with the below specs.
Summit Racing Part Number HAL-DS501
Coil-Over Shock Type Single-adjustable
Suspension Height Adjustment 0.0-3.0 in. lowered
Shock Body Material Aluminum
Shock Body Finish Clear anodized
Adjustable Valving Yes
Number of Valving Selections 18
Extended Length (in) 17.000 in.
Collapsed Length (in) 11.625 in.
Upper Mount Bearing
Lower Mount Bearing
Internal Design Twin-tube
Gas Charged No
Body Diameter (in) 2.000 in.
Bushing Material Steel
Bushing Color Natural
Coil-Over Springs Included No
Recommended Spring Diameter (in) 2.500 in.
Recommended Spring Length (in) 12 in.
Any expertise will be appreciated
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Post by poppaj on Apr 22, 2011 18:43:29 GMT -5
Your springs surely are not 300#. They should be somewhere between 110# to at the most 150#.
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Post by texoutsider on Apr 22, 2011 20:29:31 GMT -5
the car has 150s on it.......if the same springs are still there.
M.
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Post by Dave Schultz on Apr 22, 2011 21:43:24 GMT -5
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Post by poppaj on Apr 22, 2011 23:38:30 GMT -5
the car has 150s on it.......if the same springs are still there. M. That sounds about right, Never seen any drag car with a 300# spring, might as well mount the axle solid and let the slicks take the shock with a spring that stiff. Do you build any dragsters at your shop Mark, I was wondering about these 4 link setups on rear engine rails now?? |
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Post by texoutsider on Apr 23, 2011 3:24:49 GMT -5
No dragsters...........but undercover chassis does a lot of the link dragsters.
We are NOT a dragster shop..........I have built a few while in Florida, but that was another time and another life. No Poppaj, we concentrate on building what we do best, door cars and specifically NSS and F/X cars. We have found that the more we narrow our niche, the better we can be with what we do.
Dave, I think we put 150s on all of your cars..maybe some 130s on the Red car, but not likely. When we set up for shocks I have jigs that match the shock that we are going to use. The jigs are NOT what is sent with some of the shocks but what we have built up in the shop ourselves. I have found that our set up pieces come closer to the ride height that we want for the NSS cars and tire combos. We have found that the 120s are a bit soft for most of the 3200 to 3500 pound NSS cars. When we build something in the 2800 to 3000 pound range, we go with the lighter springs...in most cases some that we had custom wound and NOT off the shelf springs that most aftermarket companies sell.
I run a staggered spring rate on the Galaxie but do not send out any customer cars that way. I think we have 130s on the left and 150s on the right at this time. We also travel with our shocks set on the highest setting and adjust them back to our setup at the track. We once forgot to re set them and I came off the line in the left lane and finished up in the right...we have NEVER done that again..........if you have ever raced at Denton, we had the ole Red Ford pointed directly at the train.......lol
As for setting up the 4 links...we also have an adjustable jig for that. It is used during the initial build and is used to tailor each set up for the length of the car, length of bar and type of bracket. After the build is finished, the jig is again used to put the 4 link in MY best guess as to where we think the best overall position is for each particular car. I have "mapped" this for years with all of the builds and done plenty of computer modeling along with on track testing. We do the same deal for ladder bar setups. In fact, many of the ladder bar deals can be swapped from car to car without changing a dam thing. Point to point on all are the same. Ride height and position may be different, but the seutp all interchange.........In fact, I would betcha that you can take the entire rearend out of that Red car and put it under mine without turning a bolt. Our ole car generally 60 foots in the 1.34/1.36 range and on a good track will go 1.32...........
I usually buy components from Chassis Eng and cut and weld to our specs. On the 4 link stuff we always use an anti roll bar and have been building our own lately. If anyone looks around in our ole dirt floor shop you will see blueprints on the walls...some are heavily modified and reflect what we have found will work on specific brand cars and NSS setups. If you care to look closely and compare, the ones with all of the fingerprints and smudges are most likely what is under your car. Al;so there is a list attached to some of the blueprints...that list has car types and wheelbases on it.........we post each car to the blueprint for future ref. and to assist if the car is ever wrecked so we can simply stretch er back out on the jig and put it back as was.
There is a method to my madness..........some of it works ...sometimes.........
Mark
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