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My version of the hopnot kit, no cost to me, easy to do.

8K views 9 replies 3 participants last post by  ddeennis 
#1 · (Edited)
My version of the Hop Not kit, no cost to me, easy to do.

So I had a chance to work on my 2015 SRT 392 rear suspension today, been several months since I have done anything, my parts have been sitting in boxes just waiting on me.


I looked over the Hop Not kit to see what they was doing and looked under my car, well if all I got to do is suck up the frame to the body, I have an idea. So I went ahead and did my own version.

So the rear bushing has a "cup" shape 4" diameter washer with a bolt thru it and two rubber walls that stick past the frame bushing about 1/2", so I took the bolt out and removed the 4" dia. washer, then I cut all the rubber down flush to the frame. So everything is flat and even with frame. I cut a 4" diameter washer out of 1/4" steel I had laying around with my torch and blew a hole in the middle. I used the factory bolt and bolted on the 1/4" plate washer and sucked everything up. Well that's simple enough.

Time to move to the front bushing, took the factory bolt out, cut a small piece of thin wall pipe and reinstalled the bolt and snugged it up, so i could pry off the odd shape factory plate. got the plate off and removed the bolt. I had to cut the rubber wall off so i could flush everything with the frame- same thing as I did on the first on. I left the middle "tower" of rubber alone, since it sticks past the frame I went ahead and took the rear factory 4" "cup" style washer and flipped it and installed it with the factory bolt. Sucked up the frame to the body. Well simple enough.

tightened the pizz out of the bolts with a 2' bar.

Easy as could be. this should take care of the frame wanting to move up and down under heavy load-wheel hop.


I also got my camber bushing installed and my new lower trailing arms from bmr installed.

Got to get the car to the alignment shop next week and see where my camber is at now. other things I will do, maybe cut a 1/2 coil off rear springs depending where my camber is at. I will probably make or buy the rear differential bracket. Then get my 295 tires installed and see where my traction is at then. I already have v6 springs installed on the front with no sway bar.

here's some pic's

first one factory rear mount
second picture everything cut flush 1/4" plate installed
third is the factory front mount
fourth is everything flush around the perimeter and factory rear washer flipped and installed
 

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#2 · (Edited)
Looks like my next project[emoji4] thanks for the write up!! How are the results? It makes sense to me to get rid of the up/down movement. So for the record , you used a 1/4” plate for the rear washer , and flipped the front cup/washer, after trimming all surrounding rubber? I also need the camber bushings , so I’ll be doing those as well.

I was also going to make my own diff brace , but I got one for 140$ , so I think it was worth buying for fit, finish, and hardware. Although , if you have the tools(torch/grinder/welder) it would be a fairly easy project.
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#3 ·
Results will know in a few days, got more work to do. I put my camber bushings in and I have a little positive camber now 1/16" on the passenger side and 1/8" on the drivers side, I used a weighted string off the side of the car and measured top of the wheel and bottom thru the center line with a machinist ruler. So I went to far on the bushings, opps! The car is on empty which I would be racing on a full tank of fuel, so adding fuel should bring the top in some. I'm also going to cut 1/2 coil of the rear coils( to raise the spring rate some to help drive the rear tires into the ground on launch) so this should pull the top of the wheel in as well. So between cutting 1/2 coil and filling up the gas tank I will see where this puts me before I press the bushings out again and readjust them. I know I can have a little positive camber because when the car launches it will squat some and pull the top of the tire in ( which maybe I could simulate by jacking the front of the car up some or adding some more weight in the trunk) but i would like to get it a little closer to zero. Just not happy with the 1/16" and 1/8" measurements. I'll work on it tomorrow.

So yes I used 1/4" plate to cut my 4" washers out( you could go a little more like 4 1/4"), might be a little overkill since it is much thicker then cup/washer that was used on the rear from the factory, 1/4" plate is what I had so I used it. And yes I just trimmed all the rubber flush around the perimeter. I do wonder and maybe something you can look at when you do yours, maybe I should have trimmed some of the center bushing too. Maybe by trimming the center bushing some this will allow the frame to be sucked up even more to the body. I didn't check this, so I might revisit it tomorrow, because if the center bushing is slightly longer then the frame thickness then the center bushing will stop the frame from getting sucked up more to the body. Just a thought, I may take the 1/4" plate washer off tomorrow and just run the bolt up thru the middle bushing and see where it stops, like to have it short enough not to stop anything, since the goal is to suck the frame up and not have the middle bushing stopping it from getting sucked up.

hope this helps.
 
#4 · (Edited)
Had a chance to look over my version of the hop not kit, I noticed the rear was not sucked up to the body all the way, there was about 1/8" gap. I had to take my 1/4" (4" diameter) plate washer off, the center bushing is a little longer if you leave it flush, I had to cut the center bushing about 1/4" shorter,recess it, once I did that the rear sucked up all the way to the body.


I went to the front one and I saw it was the same way, about 1/16" of inch short of being pulled up to the body, so I cut the center of the bushing flush with a sawsall and took an angle grinder and ground down the bushing about 1/4" inch more, make sure the bushing is shorter than the frame thickness. I used the factory cup/washer and I tighten it, but ended up smashing the factory steel cup/washer. I couldn't get the frame pulled up to the body. there was still about 1/16" gap, kinda looks like maybe some rubber mount is stopping it- kinda mooshing out between the frame and body. preventing it from seating up against the body. So tomorrow I will cut two more 1/4" thick 4" diameter washers and give that a try.

So right now the rear of the frame is sucked up making the adjustment of taking out some of the factory bushing.

I hope I can get the front closed up all the way with the thicker 1/4" steel washer's. I'll update tomorrow.

I got one rear spring pulled out and cut a 1/2" coil off as well. I will have to get the other one done tomorrow hopefully.

Just ordered the rear differential brace from high horse, got me the red powder coated one to match my lower bmr arms.
 
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#5 ·
OK, my version of the hop not kit is done, here is what I did, the far rear cradle bushings are seated as noted above-cut all rubber flush and grind/recess the bushing some to allow upward movement with the 1/4" washer I made. Done.

The front cradle bushing- cut everything flush, all rubber and center bushing, then grind/recess the center bushing to allow upward movement.

I cut 1/4" mild steel plate little over 4" diameter and I also cut a smaller diameter 1/4" plate washer and welded them together to make it 1/2" thick. this has to be thicker than 1/4" otherwise you run out of threads on the bolt when you tighten it, so the extra thickness makes the washer stronger and allows room to crush the cradle to the body without running out of threads on the bolt.

See pics below.

One thing with the front cradle bushing on both side, the rubber mount oozes out at the top as you tighten the bolt, this little bit of rubber prevents a full contact of metal to metal. I tighten this as far as I was willing to tighten before I thought something would snap. So because of the rubber bushing this prevents the cradle from touching the body and it leaves about 1/32" gap. but the rubber is smashed so hard I can't imagine any up or down movement will be allowed, or at least not to cause wheel hop.

Even If I had the original version of the hop not kit I don't think the results would be any better, whether you make your own or use the hop not kit, I think the rubber will still find it's way between the cradle and the body.

With the rear cradle smashed against the body and the front tighten as much as one would dare to go, I think this is as good as it gets- for what's trying to be accomplished, which is to prevent the rear cradle from up and down movement.

1st pic is the washer I made and I painted with red tractor paint.

2nd is the view of cradle to body, if you look hard enough you can see some rubber pushing out

3rd is a closer view, this is as tight as I can get the cradle to the body.

hope this helps for those who might want to do this.
 

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#6 ·
I found this picture of what the top of the cradle looks like, this must be the rubber that is being smashed and pushed out on the front that I was seeing.
 

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#7 ·
Also found a video of the stock bushings, looks like the rear bushings have a solid china wall of rubber that allows it to be compressed and allow the rear of the cradle to be sucked up solid.

The front is not solid so when it gets tighten you have rubber and a space and rubber and a space, which shows up in my pictures, and because of the design of the rubber mount it gets pushed out preventing metal to metal contact.




Here is two video of cradle movement with stock bushings, with what I did, my cradle should no longer move like this helping to prevent wheel hop.






 
#8 ·
Test drive update for anyone who is interested.

My version of the hop not kit seems to work, got on it several times and I had no wheel hop, first time since owning this car I have not had wheel hop!

Things I did to the rear end, my version of the hop not kit(as described above in thread) , cut 1/2 coil off the rear springs- which lowered the car 1/2" and raised spring rate to drive the tires into the ground harder, installed camber bushing to straighten up tire for more contact patch ( I'm real close to zero camber maybe a touch on the positive), installed lower trailing arms from BMR.

Side note- I have v6 springs up front with sway bar removed.

The rear feels real solid, I did notice on my launches on street tires, the rear feels like it's on the edge of wheel hop, the tires don't hop, but I sure can feel like they are on the edge. Similar to tire shake at the drag strip. not sure if I'm feeling the rear diff slap up and down or if it 's my tires. I can feel some chatter so to speak.

I should have the rear differential brace coming in nest few days, so I will get that installed, I also will take my car in for wheel alignment with a full tank of fuel and get things adjusted. See where my camber is at make another adjustment if I need to. Then try another test drive.

I then will install my 295 tires last, to see how just the tires alone feel and do. they are not drag radials, they are a softer taller/wider tire than what I have now. I will do some testing to compare 0-60 mph runs, with totally stock suspension and current 275 tires best I did was 4.4 which I couldn't repeat and that was leaving black marks and heavy wheel hop on very good concrete surface. Many other passes was spinning and wheel hop 4.7 or so, I will revisit that area and see how much my times come down from all the small changes.
 
#10 ·
Thanks

I did get the differential brace installed from HHP and that took care of the "chatter" I was feeling, now I have a thump when I get on the gas when coasting, I think it's the two large bushing on the front of the differential. I think those have some up and down slop so I need to fix that.
 
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