72 Cuda g-machine - 2016 update

Author Topic: 72 Cuda g-machine - 2016 update  (Read 221063 times)

Offline johns cuda shop

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Re: 72 Cuda g-machine - running again
« Reply #465 on: June 13, 2013 - 06:33:41 AM »
Nice work Travis. Keep us updated  :bigsmile:
71 Cuda Gen III Aluminum 426 Hemi T56 6 speed 4.10 8.75 Modified & Lowered RMS coilover suspension Wilwood discs




Offline jedg

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Re: 72 Cuda g-machine - running again
« Reply #466 on: June 13, 2013 - 09:33:15 AM »
Sure is looking good!   Glad to hear that the engine is running as expected.

Offline Travis72

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Re: 72 Cuda g-machine - running again
« Reply #467 on: September 30, 2013 - 02:53:28 AM »
Another long update.

I’ve been driving the car on and off but I decided I wanted someone else to drive the car and help sort it out and to give me a 2nd opinion.  So I decided to take the car to Dan Weishaar who runs a full custom shop/suspension tuning service called DTM Racing in Yuma, AZ.  Some of you might remember seeing Dan’s blue Roadrunner which has completed in a number of events.

http://www.streetlegaltv.com/features/car-features/driving-the-hotchkis-68-road-runner-at-goodguys-del-mar-meet/

Dan works part time for Hotchkis and does their Mopar parts prototyping.  He also maintains and drives the E-Max Challenger.  For example he did the driving at Mopars at the Strip and various Goodguys events.  So I figured he was the perfect guy to drive my car.  Remember that I bought all my suspension parts before Hotchkis was making parts for E-body’s so I don’t have any of their parts on my car.

So I talked to Dan and arranged to bring the car to him Labor Day week.  Yuma is about 260 miles from me so I towed the car there.  It’s also in an area of Arizona that’s one of the hottest places in the US.  It was 110 when I was there.  While towing there I stopped at a truck stop in Gila Bend which is basically the middle of nowhere.



If you can read the temp display it says 116 degrees!   I was worried the truck was going to sink in to the asphalt.  I tried to clean the windshield of the truck but the water was drying before I could squeege it off. 



Anyway, once at DTM Racing Dan put the car up on the lift and gave the whole car a once over.  He fixed a couple little things like the front sway bar was hitting the coil over shock possibly causing it to bind, so we had to make a spacer to move the sway bar out.  Here’s the inside of the shop with Dan’s Roadrunner in the back corner along with a customers long term Duster project and a nice customers early Dart (same rims that I have on the Cuda).



After that we took it to an alignment shop down the street from his shop.  Dan takes a lot of business there, so the alignment shop set up the 4 wheel sensors then lets Dan actually work on the car.  Dan’s comment was “your alignment settings are OK for a Honda Civic but that’s about it”, so Dan changed it to dial in as much caster as possible.  The alignment settings made a big difference.  Dan drove the car pretty hard and said the huge rear tires are causing the car to understeer.  I know its recommended to keep the front and rear tire size within 20 mm’s of each other, but since I mini-tubbed the car I wanted the big tires in the rear.  Dan basically said “I understand why you did it because it looks so damn cool, but we might need to add a rear sway bar to free up the rear and get the car to turn”.



Dan has enough projects going on that E-max had to sit outside during the day while my car was in the shop, including when a monsoon storm passed through.  I have to say that E-max is even more awesome in person.  I thought this picture of it looked neat after the rainstorm had passed.



Here’s some pictures of the outside of the shop, including another customers 71 Charger that has a cool old school look to it.



You can see with my car next to E-max, that the Challenger is a good inch lower than my car.





The other thing I had Dan look at, is before I took the car to Yuma I noticed that the floorboards were tearing where I had welded the mounts for the Ridetech 4-link.



Here’s a shot from underneath.  It’s basically tearing right at the edge of the weld.  I’ve gotten on it a couple times now in first gear and I have experienced some wheel hop on bumpy roads.  Clearly this wasn’t good.



Dan called up Brett the president of Ridetech (it’s good to have friends like that on speed dial) and Brett said they’ve seen that with cars where the upper bars are not level at ride height.  My car sits a little higher than I want in the back (I have coilovers instead of air bags) and sure enough my upper bars angle up instead of being level.   Brett said I either need to lower the car more to get the upper bars level or further brace that area of the floorpan.  I decided to do both.  Dan highly recommended the Ridetech coil overs (made by Fox shocks) versus the QA1’s that I have on there.  So we ordered new custom Ridetech’s that will actually lower the car an inch all the way around.

Dan has some more work to do for Hotchkis to get ready for the SEMA show, so we stopped there.  I’ll bring the car back to him in a few weeks to put on the new coil overs, re-align the car, plus re-weld and brace that area where the upper bars mount. Lowering the car that additional inch will probably require us to move the rear brake line from the stock location.  There’s not much room back there with the 3” exhaust.

Travis
72 Cuda


Offline grimmey71

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Re: 72 Cuda g-machine - running again
« Reply #468 on: September 30, 2013 - 04:38:25 AM »
Holeeeeeeeeeeeee **** that's not cool at all. How is this not been addressed by ridetech? Since we are running pretty much the same suspensions any chance of getting more details about what he is gonna do to fix the issues you had?  Up front and in the rear. i just had to raise my rear because my diff hit the bottom of my floor pan. plus i have a steep driveway too.  I'm interested in his sway bar idea as I was planning big ole fatties in the back too.
« Last Edit: September 30, 2013 - 05:03:47 AM by grimmey71 »

Offline barracuda7199

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Re: 72 Cuda g-machine - running again
« Reply #469 on: September 30, 2013 - 07:17:57 AM »
It's a good thing you found that! Could have been ugly!
Brandon

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Offline johns cuda shop

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Re: 72 Cuda g-machine - running again
« Reply #470 on: September 30, 2013 - 07:52:39 AM »
I have the Street Lynx in mine ,I have my rear bars sitting 10 deg downward., I have the shocks sitting soft now ,so adjusting them will level them out a little more. I have TTI 3 inch exhaust in it now and have to say its close but after cycling the suspension up and down nothing hits.  Sorry about the welds on the Ridtech system. I heard from some other people about this happening too. Some 1/8 plate welded around the floor should gusset it. I must note, I see a lot of welds fail on because the weld joint was not clean before welding causing porosity . I tend to weld a little hotter than most and use the Tig when ever possible.
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Offline dutch

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Re: 72 Cuda g-machine - running again
« Reply #471 on: September 30, 2013 - 10:03:45 AM »
the weld didn`t fail, the floor did.  They should have instructed to use a thicker piece of sheetmetal fully welded to the floor, then weld on the bracket   :2cents:
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Offline jedg

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Re: 72 Cuda g-machine - running again
« Reply #472 on: September 30, 2013 - 10:09:23 AM »
Great update Travis.   That's super cool that you were able to get Dan to look at your car.  Is the engine still working good for you?

Offline johns cuda shop

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Re: 72 Cuda g-machine - running again
« Reply #473 on: September 30, 2013 - 01:11:00 PM »
 :poopoke: In reality the suspension brackets should be attached to a frame section something like the RMS Street Lynx... I have heard of Ridetech and XV rear suspensions  have had problems
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Offline brads70

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Re: 72 Cuda g-machine - running again
« Reply #474 on: September 30, 2013 - 03:23:14 PM »
:poopoke: In reality the suspension brackets should be attached to a frame section something like the RMS Street Lynx... I have heard of Ridetech and XV rear suspensions  have had problems

I'm no "expert" but I agree. Basically they are copying the traditional GM 4 link suspension( that's mounted in a full frame car and then trying to mount it in a unibody car) and I do know from first hand experience that if you change the dimensions of the upper arms a 1/4" you get wheel hop . On my Buick GN clone I built I screwed up position wise on welding on the upper rear end mounts. I bought Edelbrock adjustable rear upper control arms to try and fix the problem. It didn't..... car had bad wheel hop and little traction.
When I tech street stock circle track cars I'm often asked why I don't measure the rear of the chassis to see if it's been screwed with ( 78-87 GM G-body chassis) I reply "I assume GM spent millions of dollars engineering it all to work great and it does if you leave it alone." I can usually tell by the track performance if something has been moved or it's bent. In which case I don't need to worry about them from a "cheating perspective" as they never finish up front anyhow! Even if they try and lower the chassis by what ever means ( lowering the rear clip or the whole car) it doesn't work It's engineered to work in a certain height range, and if you screw with it bad things result.
Not to run any specific system/aftermarket supplier down but if they don't have it engineered right you won't get positive results  I don't care how much money you throw at it in fancy looking parts. I wonder if sometimes the aftermarket compromises the engineering in order to make it easier for them to make ( and sell), like using a blend of stock Mopar mounting points (leaf spring mounts ) and  ease of position for the upper mounts?
Unless your certain as to where the mounts should be I'd also make the mounts adjustable, so that you can experiment as to what works , then weld it in position. I'd go to your local wrecking yard with a tape measure, find a GM 4 link chassis and make notes as to where the  mounting points are at. Little things like how far back from the center of the axle the mounts are on the bottom and top. Arm angles, lengths, what happens to the pinion angle during suspension travel, etc... to establish a ratio and compare it to what you have. But that's just me I never trust anyone else's work!  :lol:  Thinking and planning doesn't cost a lot of money..... reworking the finished product does though.  :2cents:

Structurally in your case what about making a " connector" on the inside of the car (if there is no room underneath?)  to fit in behind the rear seat that ties the 2 upper mounts. Like 2  6"x6"x.080" flat plates welded and bolted to the mounts, and then a piece of square tube welded to those 2 plates on the inside behind the rear seat extending over to the frame rails?. Otherwise IMO that's asking the floor sheet metal to do way more than it's designed for ?   That area was designed for a muffler mount, not suspension?

That's pretty cool that you could get Dan as a second set of eyes!  :2thumbs:  He is a pretty smart cookie!
« Last Edit: September 30, 2013 - 07:25:55 PM by brads70 »
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
Proud to own one of the best cars ever made!!!!!

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Offline Travis72

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Re: 72 Cuda g-machine - running again
« Reply #475 on: September 30, 2013 - 11:38:50 PM »
The normal bolt in installation for the Ridetech is as follows:  The upper mounts on the underside of the car bolt to the frame rail then sit tucked up to the floorpan.  On the inside of the car there is a brace that connects the two mounts.  You then drill through the floorboard and 3 bolts on each side go from the inside brace through to the under floor upper arm mount.  So the floorboards themselves only get sandwiched between the brace and the mount.  Perhaps by welding it in like I did it actually made the floorboard more stressed than in the bolt in application?  It probably doesn't help that I have ~550 hp now with 335 tires.

Brad, take a look at what the interior brace looks like, it looks kind of like what you're describing.



Unfortunately RMS wasn't making the Street Lynx when I put the rear suspension in.  Yes I've been building the car that long.....

The only thing I blame Ridetech for is that no where in the instructions does it say that the upper bars have to be level.  Perhaps I should have been smart enough to figure to that out, but it would have been nice if that was mentioned.  Maybe with the Shockwave air bags that its designed for it would be low enough and the upper bars are automatically level?   :dunno:

I'm not planning on putting the back seat in since the roll bar is back there.  At one time I thought about putting the seat in for looks but now my plans are to just make a divider panel from the trunk and build some sort of flat floor as an extra storage area.

So given that, Dan and I were talking about either just bracing up the area with plate steel to spread out the load.  Or doing that plus adding in tubing that would go from the plate steel and tie in forward to the roll bar.  If anyone has any good suggestions please let me know.

Travis
72 Cuda

Offline grimmey71

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Re: 72 Cuda g-machine - running again
« Reply #476 on: October 01, 2013 - 12:23:01 AM »
This has me thinking about maybe a nice stout u-channel between the frame rails for the upper arms to mount to. Either way please keep us (me) updated as I am kind of concerned about my suspension now. My bars are level with the floor but still scary.

Offline brads70

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Re: 72 Cuda g-machine - running again
« Reply #477 on: October 01, 2013 - 03:47:57 AM »
Brad, take a look at what the interior brace looks like, it looks kind of like what you're describing.



I'm not planning on putting the back seat in since the roll bar is back there.  At one time I thought about putting the seat in for looks but now my plans are to just make a divider panel from the trunk and build some sort of flat floor as an extra storage area.

So given that, Dan and I were talking about either just bracing up the area with plate steel to spread out the load.  Or doing that plus adding in tubing that would go from the plate steel and tie in forward to the roll bar.  If anyone has any good suggestions please let me know.

Travis
72 Cuda

Ah gotcha!  :2thumbs:  Sounds like you have a good " plan of attack "
Only downside I see with this set up is additional weight , .... and mounted up high.
Brad
1970 Challenger 451stroker/4L60 auto OD
Barrie,Ontario,Canada
Proud to own one of the best cars ever made!!!!!

My restoration thread 
http://www.cuda-challenger.com/cc/index.php?topic=59072.0
 My handling upgrade post
http://www.cuda-challenger.com/cc/index.php?topic=73985.0

Offline johns cuda shop

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Re: 72 Cuda g-machine - running again
« Reply #478 on: October 01, 2013 - 07:35:04 AM »
Sounds great Travis, keep us updated on the progress with the repairs....  :bigsmile:
71 Cuda Gen III Aluminum 426 Hemi T56 6 speed 4.10 8.75 Modified & Lowered RMS coilover suspension Wilwood discs

Offline Travis72

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Re: 72 Cuda g-machine - running again
« Reply #479 on: December 18, 2013 - 04:31:06 PM »

Finally time for an update.  I took the Cuda back to Dan at DTM Racing on Halloween.  This time towing to Yuma the weather was much different… like 71 degrees different.  :D



I got to the shop and met Joe (member ff6849 on here) and he brought by his sweet 73 Cuda to check out my car and Dan’s shop.  It was fun meeting a member on here and checking out each other’s cars.  This is Joe awesome looking 73 Cuda.



Then it was time to get to work, as Dan started taking the car apart he realized the Ridetech 4-link was basically binding up.  You have to really put some force on the upper links to get them to go into the brackets.  I think that was part of the reason the upper mounts were tearing.  I had the shop that installed the roll bar also install the 4-link and it seems they didn’t get the angles right.  I probably should have installed it myself, but I didn’t trust my welding.  With the upper links binding it was actually breaking the metal sleeve inside the bushing plus it was oblonging the hole in the coil overs.






Dan and I discussed what to do and considered making new custom arms with heims joints, but ultimately I decided to just have Dan start over and basically cut all the brackets off and re-weld everything at the correct angles.



The first thing Dan had to do was re-weld all the cracks in the floorpan.  The cracks basically went almost half way around.  Scary!  At that point Dan fabricated up some braces and tied them in to the rear floorboard crossmember.



We also replaced all of the QA1 coilovers with Ridetech coilovers.  The new shocks lowered the car ~1” in the rear.  This new lower stance looks awesome but causes some clearance problems. There was no room for the tailpipes so we just pulled them off for now.  I will take it back to the exhaust shop and have them but in a bigger bend to tuck them up higher.  Dan also relocated the axle vent for clearance.



Here’s how it looks with everything finish welded.  I’ll have to repaint the rear axle one of these days.



On the front suspension we replaced the QA1 heim joints with Aurora joints which are top of the line plus new Ridetech coilovers.  The heims are the same ones Hotchkis uses in their kits. Dan also installed the little rubber boots for them as well.  With the new heim’s Dan was able to get 6.3 degrees of caster where previously we could only get around 4.



With everything completed the car handles amazing but there are some clearance issues that I’ll have to deal with (namely the driveshaft).  Before you could reach in to the rear wheelwell and put your hand straight across and touch the top of the tire.  Now the tire is tucked up in to the wheelwell.



This is a cool picture that one of Dan’s friends took and photoshopped and I just liked how it looked:



Travis
72 Cuda