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Front and rear suspension upgrades GTS

biomedtechguy said:
My main goal in my front suspension replacement/upgrades was greater adjustability to be able to have it dialed in "just right", overall appearance and designation as a "Resto-Mod/Pro Street" vibe, and better overall performance.
My focus is quarter mile drag racing performance and cruising on the street, not "corner carving".
I believe it's accurate to say that using the QA1 front suspension components is keeping the factory engineering design, but replacing all of the parts with modern upgrades.
NOTE:
I used ALL QA1 parts in my front suspension replacement including the K-member, EXCEPT FOR a key component:
The upper control arms (UCAs) are SPC and the reason why is lack of adjustment range with the factory "cam style" UCAs don't allow enough range for my car, and I had 2 different front end alignment techs say so.
@BergmanAutoCraft had a nice in-house tweak to the SPC UCAs that is specific to MOPAR, but SPC also just recently changed the design of their UCAs, which I read about but honestly I don't understand.
I got the SPC UCAs in my 70 Roadrunner from SPC for MOPAR, and they have worked fine so far.
@BergmanAutoCraft
Would you be kind enough to describe the advantages and differences between your SPC UCAs and the "stock SPC UCAs" (if you have any left to sell) and the differences with the new design SPC UCAs for MOPAR please?
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Just seeing this now as I'm not getting email updates for some reason.
SPC has been making control arms for the Mopars for some time now. However, my testing shows the rubber bushings provided in their arms do not offer enough of an interference fit to stay put when loaded through cornering and braking. I adapted their delrin mounts using custom made sleeves and spacers. They mount properly and solidly now on Mopar applications. Nobody else does this as my competition are simply resellers. Most if not all have ever touched these arms much less evaluated their function. I still have these if anyone would like a set which is why they are still on my site.
SPC redesigned all their arms recently and went to a forged design and uses a proprietary ball joint that is taller than the traditional K772. This offers reduced body roll as the moment arm is shortened slightly. The new design is on car double adjustable and appears very robust. I am not sure why they went to this design.
 
BergmanAutoCraft said:
my testing shows the rubber bushings provided in their arms do not offer enough of an interference fit to stay put when loaded through cornering and braking. I adapted their delrin mounts using custom made sleeves and spacers. They mount properly and solidly now on Mopar applications.
Click to expand...
I'm sending you a PM
 
BergmanAutoCraft said:
Just seeing this now as I'm not getting email updates for some reason.
SPC has been making control arms for the Mopars for some time now. However, my testing shows the rubber bushings provided in their arms do not offer enough of an interference fit to stay put when loaded through cornering and braking. I adapted their delrin mounts using custom made sleeves and spacers. They mount properly and solidly now on Mopar applications. Nobody else does this as my competition are simply resellers. Most if not all have ever touched these arms much less evaluated their function. I still have these if anyone would like a set which is why they are still on my site.
SPC redesigned all their arms recently and went to a forged design and uses a proprietary ball joint that is taller than the traditional K772. This offers reduced body roll as the moment arm is shortened slightly. The new design is on car double adjustable and appears very robust. I am not sure why they went to this design.
Click to expand...
Have you put the wood to the new arms yet? Keep us informed as you put them to the test when you run your cars at the track events and roads in your area. Would like to see how they handle true tests as opposed to loading/unloading on trailers or only being driven like a grandma on smooth road.
 
ckessel said:
Have you put the wood to the new arms yet? Keep us informed as you put them to the test when you run your cars at the track events and roads in your area. Would like to see how they handle true tests as opposed to loading/unloading on trailers or only being driven like a grandma on smooth road.
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Yes we have. One of my friends has a 68 Charger who is an avid autocrosser. All good. We'll be running together this weekend at Drive Auto X in Pa.
 
Nice. Will watch for your feed back. I have some arms from FF that have not been used yet on my car, 65 Coronet, but I like the features of the SPC units.
 
ckessel said:
Nice. Will watch for your feed back. I have some arms from FF that have not been used yet on my car, 65 Coronet, but I like the features of the SPC units.
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The double adjustment makes alignment much much easier. The increased range also insures you can achieve the specs you want.
 
I am researching complete suspension for my 71 Charger project. I am planning to use a Borgeson PS box, Holley PS pump and will be running a 5.7 with a 4 or 5 speed.
 
+1 for GERST. Dead straight @ 133mph first pass off the trailer and I even used a DIY alignment kit.
 
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Center links are a non wear item. Only possibilities would be collision/Dukes of Hazard maneuvers or someone didn't tighten up the tie rod units when the were installed which would wallow out the holes.
 
ckessel said:
Center links are a non wear item. Only possibilities would be collision/Dukes of Hazard maneuvers or someone didn't tighten up the tie rod units when the were installed which would wallow out the holes.
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Big help, and I had that notion, that if it is guilty of contributing to "play" in the steering, it's from "wallowed out holes" vs a replaceable part. I need my front suspension alignment "tweaked" because it has only been done once (according to 'by the book' specs) since EVERYTHING was replaced and a lot of other work done related to the front and rear suspension, it has settled in, and the biggest problem I'm having is it "tracks" when there are dips in the road parallel to the road and direction I'm going.
So I'm going to get it to the shop when I can, and take a close look and see where I stand, with the old school tech/shop owner there to guide me.
 
Along with worn items, alignment and tire issues can make it track. Speaking of alignment. When you get it done, make sure they hang targets on all 4 wheels. Not front only. Have them check the "thrust angle" too. This is the measurement between the from and rear wheels on each side. If its off some, you can get shims from Hotchkis or BAC that go between the front spring hanger and the unibody structure. If its off alot, plan on a date at a collision shop on their frame rack to see what's bent on the structure. You may have a bent diff housing too. When you see vehicles coming at you, or are in front of you, that look like they are going sideways, this is what the thrust angle measurement is for. The front needs to get aligned in relation to the back so you don't have this problem. Also, you are not going to get this all taken care of for a $59.95 alignment. Plan on at least 2 hours labor shop time to get your stuff where it needs to be. Bargain alignment is most likely going to give you the "set the toe and let it go" alignment. Getting all the stuff set correctly on old cars takes time. You must pay for that time. Bargain shops are relying on volume jobs where there isn't much to mess with, so they get more done in less time netting more income for the shop.
 
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ckessel said:
Along with worn items, alignment and tire issues can make it track. Speaking of alignment. When you get it done, make sure they hang targets on all 4 wheels. Not front only. Have them check the "thrust angle" too. This is the measurement between the from and rear wheels on each side. If its off some, you can get shims from Hotchkis or BAC that go between the front spring hanger and the unibody structure. If its off alot, plan on a date at a collision shop on their frame rack to see what's bent on the structure. You may have a bent diff housing too. When you see vehicles coming at you, or are in front of you, that look like they are going sideways, this is what the thrust angle measurement is for. The front needs to get aligned in relation to the back so you don't have this problem. Also, you are not going to get this all taken care of for a $59.95 alignment. Plan on at least 2 hours labor shop time to get your stuff where it needs to be. Bargain alignment is most likely going to give you the "set the toe and let it go" alignment. Getting all the stuff set correctly on old cars takes time. You must pay for that time. Bargain shops are relying on volume jobs where there isn't much to mess with, so they get more done in less time netting more income for the shop.
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Thanks. The "crab" is something I never want to see one of my vehicles do, and I don't have that problem. The guy I'm speaking of does front and rear "targets" at the same time as you suggested, and the old school owner of this shop does more than alignment, but he was referred to me years ago and is very meticulous.
I appreciate the detailed reply.
 
@BergmanAutoCraft
I'm watching, following
Popcorn The Stig Eating.gif
 
Much of this thread is about front suspension, what about the rear? I have looked at springs from Firm Feel and Hotchkis and am open to different options. This would be for a 71 Charger with a 5.7 and a manual trans. I definitely want it to handle and intend to have it relatively low and level.
 
Back in the day of the Kit Car program, they had three different springs arches to use. +1", 0", -1". They could be used for b or e body. I had a 70 Chally. Used the 0 arch units. I'd have to look at my books for how many different spring rates they had but I want to say the KC units I used were 160lb per inch. I believe the SS units are 180. Stock HD's are 120? Anyway there are some choices to be had in the circle track world. I got lucky on mine as they and the 1.06 bars were not heavy enough for this particular circle car so they had them stored after using for a few laps. Score for me.
 
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