Coil Over Conversion Installed

Torsion bar to Coil Over Conversion​

This is my overview of going from Torsion bar setup to a Coil Over conversion. Included is a parts list of what will be needed (depending upon which way you go, or mostly the way I went with), a review of the setup and a few pictures of my setup installed.

First what is needed for this:

PARTS NEEDED

• Atomic's KIT (upper & lowers w/ hardware)
• QA1 DS301 Coil Over Shocks http://www.summitracing.com/parts/hal-ds301/overview/
• QA1 Spanner Wrench and Thrust Bearing Kits - # 7888-110 http://www.summitracing.com/parts/hal-7888-110/overview/
• QA1 COM8T-102PK – Steel Bearings (upgraded ones) 2 sets (4 bearings total)
  (this package comes with 2 bearings each package) http://www.summitracing.com/parts/hal-com8t-102pk/overview/
• Hyperco Springs part # 7B1200 (1200lb spring) – Ebay
• Spacer - 1/2" (top) http://www.summitracing.com/parts/aaf-all18572
• Spacer - 3/8" (bottom) http://www.summitracing.com/parts/aaf-all18571
• Bumpstops – http://www.summitracing.com/parts/ens-9-9101g/overview/
• Pro Comp Shock Mount Conversion Kit # 690001 http://www.summitracing.com/parts/exp-690001
• Anti-Seize

Click all pics for bigger ones


--Long shocks on both outter sides are my rear shocks--

Better pic from Iregrets install


Few notes on parts list

When ordering parts make sure you double check what you are getting. (read the parts descriptions) I choose the DS301 shocks per Richard (Atomic) suggestion as it was the correct shock for my application. So, be sure to use the correct shock for your application as it will differ. (unless you want to replicate my setup)
If ordering the DS301 shocks do not freak out when the shock is received, it is about the size of a cell phone. It will work though.

The spanner wrench and bearings kit is an optional purchase, but will ease when raising or lowering the coil overs.
Bearings shown only


Must order the COM8T Steel Bearings. These are upgraded bearings from the original qa1 shocks. These will be able to handle the weight of the vehicle; the poly ones supplied w/ the shocks will get destroyed quickly. 4 bearings will be needed if you choose the pro-comp adapter way, 2 for each shock. If you choose the stud top mount, then only 2 will be needed for the bottom of shock, but will need to purchase an upgraded bushing for the stud mount. (currently none have held up to my knowledge 3/1/14)

Pic of steel bearing installed


Pictures below are why I went with the Pro -Comp adapter instead of using a stud mount w/ bushing.
Poly Bushing that comes w/ qa1 shocks after only just sitting on the weight of the truck (pic courtesy of Iregret)


Bushing installed - notice how squished it is


The rest of the parts are self-explanatory, if not feel free to ask. Most of my information and research came straight from Atomics threads (and communicating with him personally) as well as FILL IN with his help.

INSTALL

First if you have no knowledge of removing suspension or shocks, I recommend paying a professional to do the install for you. (I take no responsibility for any damage, torn relationships, sold vehicles, nothing. Do at your own risk) I had a good friend that builds custom dropped trucks/suvs helping me w/ this whole install. 4 hands or a friend is very helpful for this install.

**Note – If you want to see the difference, make sure to measure the before height**

To get started : (not going into detail on this)
Get vehicle lifted off ground and secured. A lift is quite helpful. Take off wheels and front shocks. Assemble the coil-overs (put springs on, bearings, clips, anti-seize, etc) Best to do before you get it into this, just in case you need to run to the store for something.

** If you choose you can take off keys / torsion bars / & torsion bar x-member if you choose to do so. Please be very careful when uninstalling these. **

This is how I did MY setup – Just a guideline if you will for others

1. Place atomics upper bracket on upper shock perch. (the one meant for the side you are working on. There is a driver’s side and a passenger side)
2. Get the pro-comp adapter and using the supplied nut, bolt it up through the upper bracket & shock perch and tighten it up. Make sure it is placed well and flat against the frame. There is a plug there, (speed sensor?) it will make contact, but I did not have to unclip mine. My bracket did not go completely flat as the shock perch on the frame was added after GM made the frame. (So, it is not flat against it all the way, but very close)
3. Then take the lower bracket from Atomic and bolt it to the hole on the lower control arm where the shock bottom would normally bolt to.
   
4. Next take the assembled Coil-over and do a mock up. Making sure all is right and fits correct. **note, I had to jack up the LCA a little to get the shock to mount to the top, this appears to be normal from my research, does not affect anything**
5. While mocking up is being done, check for clearance all around the spring. I.E. will it make contact with anything, but remember you have no load on the suspension. To double check at your discretion jack up lca to normal level and check clearance.
   
   Pictures of clearance that might cause issues (reason for cutting)
   
   
6. Now it gets interesting and power tools are needed. (Think of tim allen) Mine spring was hitting the very corner of the bump stop and bump stop bracket. (the piece of frame/metal that the bump stop bracket is welded to. ) In order to fix this dilemma that piece needed to be cut, (as atomic has mentioned). If you fear cutting up your Tahoe then maybe this is not for you, but I guarantee it will be well worth the heartache. Basically your cutting an angle off that bracket. (hopefully picture makes more sense) **Take off shock before cutting to not accidentally cut the shock / spring. **
   
   (Iregrets Cut)
   
   
7. Now w/ the corner gone, double check fitment and clearance.
8. Everything looked good to go on my setup. Now, here is where install will differ from others.
9. Take off the shock, but leave the pro-comp adapter attached to the upper bracket, but remove shock completely.
10. Weld the upper bracket to the frame. For assurance spray w/ rust-o-leum or similar since raw metal will be exposed as well as on bump stop where it was cut.
    
    
11. (Or you can drill holes in the frame and bolt the bracket to the frame. I choose not to do this b/c after looking at it on the driver’s side where the bolts / holes are supposed to go, the engine motor mount is exactly right there. I saw no way to get to the bolts on the inside of the frame to tighten them down.
    
    Here is what your working with on the inside of frame
    
    
12. The upper bracket is optional honestly; it is just for reinforcement of the upper shock perch. So if hesitant at all, you can try to just use the pro-comp adapter and disregard half of 6, 7 & 8. I have seen others in my search that are doing it that way.(no information on how it has held up)
13. By this time, the upper mount should be welded on, pro-comp adapter bolted up and tight and upper mount done. Hard part is now over.
14. Now get the coil over and mock it back up again. Bolt it to the bottom bracket & the top, (jack up lca if needed to reach / mount top shock bolt to the pro comp adapter. I had to jack it up a little.
15. Here is where I removed my Torsion bar setup. The bars & keys but left the x-member. (it serves no purpose as there is a real x-member right behind it.)
16. If all is good and well, tighten up the bottom bracket- both bolts. Then tighten up the top bolts. Basically tighten all bolts. (you can tighten up the bottom bracket in the beginning if you choose)
17. Now, you should have the coil over fully installed and ready to mount the tire back up.
18. Sit back and take a break after both sides are done and admire that both those 5” shocks actually fit (if you choose the shocks I did)
19. Put wheels back, tighten accordingly and lower vehicle.
20. Check clearance / movement / measurements etc. and that you can get off lift. (ha ha)
21. Re-adjust if needed, remember suspension has been messed with. Go for a test drive and come back and re-measure and adjust to desired height.
22. That’s it, all should be tight and adjusted and the ride improvement should have been felt on the test drive.
23. Now go drive it again and really feel the difference you just created. It is truly a vast improvement of t-bars.

The install time depends upon you or the installer. It took me and my friend w/ a few breaks about 2.5hrs, testing / fitting / mocking / assembly of shocks/ etc.

There may be some steps I left out or did not mention some things. I was not going to go into full detail as this is really not quite that hard to do. It really is a bolt on ordeal with the exception of the upper bracket and cutting the bump stop bracket is needed. I only listed the way I did my install. Whichever top shock mount you choose will differ w/ the install. I.E. stud mount straight to upper mount. No welding or drilling required for upper bracket. Only modifications needed is the bump stop cut.

In order for the above to make sense here are some installed pictures:
Click image for bigger pic



Big Pictures for reference, rest just click for bigger size



Few notations about my Tahoe:

• It is a 2005 with 285/50/20 tires which ends up being a 31 tall tire.
• 2WD
• I have - Mcgaughys 2" drop sprindles / Rear LCA / UCA / Panhard - (all adjustables) /Sways/ Endlinks/ Free Travel mod/ *STOCK FRONT LCA & UCA*
• I have fender flares (factory)
• Daily Driver
• Beltech 5305 rear springs
• leveled at 32" ground to fender all around
• Center Hub to Fender 17" (4/28/14 - front height is 31.5 )

IMPRESSIONS

Since I was at a suspension overhaul I also installed QA1 RS702 adjustable rear shocks. Most of my impressions will try to focus on front impact.

Starting off on the test drive around to settle the suspension I noticed a difference immediately, a much softer ride in front. The big difference came on the ride back home; about 50 miles on back roads and freeway traveling. First let me say, I forgot I had the front shocks on setting 5 and the rear on 10. Adjusting the knob only 1 click will make a difference. But on the way home not even 10mins into the drive I could not believe the vast amount of difference I was feeling. This, coming from a jar bouncing ride w/ about 1 to 2” of shock travel on the previously installed shocks to having the correct shocks installed w/ the t –bar setup gone. I felt no bumps at all, no jarring bounce, no squeaks, no rattles, nothing but pure bliss. Some of the roads were twisty, (I did not go crazy as I just did the install and still had that, how is my 5” shock holding this beast up mentality) but took the turns w/ even more ease than before. No more side to side movement, it felt as though I had much more control of the front wheels or front as a whole. It is hard to explain. The best explanation I can say is it’s like driving a car w/ a good suspension setup and knowing that you have control of it at most times. You point left it goes left, no movement. Not sure if that really makes sense. The other road or time I noticed an improvement is the entrance to my neighborhood is terrible, like going over 50 million little speed bumps and now it is bearable. I do not get bounced up and down the whole way through the entrance. It cushions the bumps and the only way I can think of, is it feels like driving a car, not a slammed Tahoe. I need more time to actually respond on the feeling of the ride. At the time of writing this I have only put around 50 miles on it and in just that little time has me honestly blown away on the improvement. Just feels more planted & more in control. To copy Atomics words “It’s kind of hard to verbalize just the truck feels more confident and secure, makes it a lot more fun than it should be.”

I messed with the qa1 settings and put on 15 clicks out of 18 which is the firmest, and it still rides much much better than the t-bar setup. Actually, was very impressed w/ the ride at 15 clicks, truck did not move at all. Feels like I could take a corner at any speed. (Which I do not condone) But I love the feeling of driving it now, it’s like a new vehicle. (sort of)

Cliff notes for those that don’t want to read:
WOW, the feeling of driving is fun again in a slammed Tahoe and rides 100x better than with the t-bars. I find myself making up places to go to keep driving it. Well worth the investment and time. You will not be disappointed. If for some reason you are, i would love to know why!

Questions that may come up

A little negative for those that want to go really low. With my setup using the pro-comp adapter, my Tahoe is about as low as its going to go right now. 32” ground to fender or 16.5” center hub to fender. The qal coil overs are on the lowest thread possible. I can only up from here. Until someone comes up with a bushing for the stud mount type shock that holds up to the weight, I can live with my height. Otherwise i think the pro-comp adapter is about 1.5", so then i could go to about 30" height.

This setup to me, (do your research) will fit any application, meaning if you are at stock height and want a much better ride, or if your lowered just a little, or if you want to raise your vehicle. It is all in the shocks that are chosen for the application.

Any questions you may have or I missed over please feel free to pm or ask away. A more knowledgeable person than myself would be Atomic –Richard himself. He has helped me very much and appreciate his help and time. Also thank my friend Low ain’t Enough for helping me with the install.

Thank you Richard AKA Atomic for your time and help & Iregret for allowing me to use his excellent pictures and referencing his thread from PT.net

For Reference and more info see below threads
Atomics Thread on TYF - http://www.tahoeyukonforum.com/forum/showthread.php?t=57560
Atomic thread on PT.net - http://www.performancetrucks.net/fo...2/99-07-4wd-front-coilover-conversion-518118/

Great thread on PT.net that i followed and asked questions also to. He has many pictures of the install, clearance issues, height, etc. Great thread from Iregret - Justin
http://www.performancetrucks.net/fo...lverado-project-charlie-murphy-489579/page25/

** NOTE: For those wanting to do only stud mount Install (no pro-comp adapter) This is from Iregrets thread. he is the thread i am watching closely to see what he comes up with for a suitable bushing install. He has used stock / poly / delrin, These i believe are the new poly he got and custom cut & added washers to spread the load. -- Not my setup--

W/ stock bushing (as above pics)


WIth new Poly Bushing w/ fender washers as well. No results yet

This is installed & weight on.


Pictures of Stance after Coil Over install

Tahoe is dirty - weather is not the best lately as we all know. But pix to show all the stance

Quick Video of movement. QA1 shocks set to 0. Softest ride
This is a video of my bro, showing the bounce i know have. lol. Click for the video


Before


After

Installed on March 1, 2014
Intial ride there was a realization that something was changed for the better. Freeway ride home was much softer, bumps were cushioned much more than before and felt there was more control of the tahoe at freeway speeds compared to tbars. shock settings were all different, so can not comment too much on ride quality. But even with that, very noticeable impression of softness was well established on the 50 miles ride home. No regrets that i just swapped out something for a unknown product. lol.(at least to me) and spend $ on unknown conditions. No regrets. Even pulling into driveway was a instant notice of softness and more absorption of bumps. It was a nice feeling coming from being slammed and horrible ride to a actually bearable ride. ( no alignment done)

3/5/2014
100 miles or so
Still going strong. No issues and ride quality is getting fine tuned. Front is on 12 and rear is at 10. For me still needs stiffer up front, which should say something about how well the ride quality is even at this settings.

3/15/2014
Around 300 miles
Still no issues & rides great. Still fine tuning suspension adjustment on shocks.

3/21/14
First time I really drove all over with this setup. Now remember on this trip, I had 265/70/17 tires / spares on the front & still no alignment yet.
Shocks on (i think) Front - 16 Rear - 14
Drove about 100 miles today and did not have one complaint about the ride. I went from freeway to side roads, to construction roads, to worse roads here. Did not have any troubles at all. The shocks took the impact of the "bumps" like a champ and not one bump was jarring. I think the rear shocks higher setting helped w/ the ride quality better. Front was amazing, i really was surprised how well they bumps were handled. The ride on this setting is a little stiff, but that's the way i like it. But even w/ that setting, it rode great, not jarring at all. It was a very comfortable ride around, with no complaints from me, except being stuck in traffic all the way back home for 2 hours.

4/2/14
One month update

Finally got tie rods installed, No alignment yet - coming next week.
But man, it rides better for some reason now. The steering is much better and firm, sports car almost feel. the front feels smoother as well when hitting dips or bumps in the road. Im not sure if tie rods would make a difference, but they do to me. Before use to be bunch of noises, pops, and did not feel like 100%, now i swear it made the coil overs ride better then before. Ride is still very good. I am still not annoyed with it or anything. Love the ride comfort now. So after a month of driving all over the place, rough / smooth / uneven etc roads, it drives very well and smooth ride for a slammed tahoe. Very happy with my decision to splurge on atomics setup along w/ coil overs.

Alignment coming soon. b/c now my wheel is all jacked up and pulls right.

4/8/2014
Got the front end aligned. Just a short trip home from work and can tell it did make a difference. It feels more planted than it did before, turning has improved as well. But keep in mind i did tie rod ends also which screwed it all up and my tires were quite sinked in at the top after install of all this. But more planted and drives good. Also noticed its not as bumpy taking the same road i do to and from work. More review w/ more miles after alignment. But so far, better improvement with the alignment, HIGHLY suggest getting one after install.

Want to note as well. I did not need a camber kit. Wheels are straight, drove straight and aligned with no problems, but i also go to an old fashion shop that does it by hand, not fancy computers.

4/11/14
Couple days on alignment now. It has a better ride than before without the alignment. Now i will be able to see the full potential of the ride quality with the tbars gone and coil overs up front. Within the few days of driving after alignment put about 100 miles on since and have noticed the quality of the ride is much more precise. Meaning that bumps feel they happen in unison, unlike before it felt off and jarred wheel one way either left or right over bumps. Now it does not at all. The usual bumps i brace for before the install no longer have that affect on the ride. I just drive w/o bracing myself and can actually drink a soda without spilling it while im driving. Bumps are less bumpy, turns are more controlled, steering feels more in control, all around much better ride than it was without a alignment. Thus far still happy with my decision on coil overs.

Only thing i have noticed is that i am quite low now after alignment 31.5 front ground to fender. Need to get center to fender measurements. Once time is allowed, i will be raising it up to 32" to match the rear.

4/25/14
Constantly changing settings on shocks. Drive a day on one setting and go lower (meaning softer) Still changing them today, but ride has improved for softness and comfort. Been really busy and have had no time to cut off stops / add bump stops & raise the front up. Will do soon though.

4/28/14
Now I have some miles on the setup here is a little review thus far.

First, I have been tweaking the shocks setting daily for around 2 weeks now. I have started at around 12 clicks from 0 and slowly gone down, softening the ride. I have gone down one click a day to get a full feel of the change and not just a quick drive around, actual day use of the change. I am not sure where they are now, but the ride is much more softer and cushions the bumps in the front much better. ( sometimes too good) The firmer settings were stiff and gets stiff quite fast the higher the click. (the reasoning behind my one click at a time.) From another point of view, my bro was me at lunch today and said its bouncy now, but it rode better now.

This will be a review of the rear as well, even though has nothing to do w/ the front. (sort of) but the rear seems to be a problem now. Its kind of bumpy and feels very stiff when bumps are hit. Not jarring, but very stiff feeling. So to compensate for this, today i have started to dial in only the rear settings and leaving the front alone. (as i am happy with the front now) Since the front and rear work together for a soft ride, I am tackling this at the same to see where this can end up and hopefully by the time this is all settled and done, there will be valuable information for others that want to be low and ride good. (dont belong in the same sentence, lol)

After seeing someones comment about bags in the rear springs, i may try that setup and see what changes.

All in all I am still very happy w/ my setup and just needs tweaking to be even better. So if you plan on doing this, do not think it is a instant fix for the ride. It makes the ride better, but must be tweaked to each individual's feeling.

5/10/14

Cut the front bump stop cups off & added helper bags in the rear & raised the front up to around 32.5 little less.

First i'll talk about my findings today:
The shock has been bottoming out on the cap (top part of shock) either while driving around and hitting good sized bumps or its from the stupid speed bumps at work. Its not bad, but signs that we could see it was hitting. Was not hitting the bump stop bracket, but the shock, but also remember i was at the bottom of the coil threads. lowest setting. The shock had no room to travel and the spring load was from my understanding not much at all, Hence my reviews of wanting a harder spring. I think the correct term is, i did not preload the coil overs correctly and rushed into the setup. Also realized rear bump stop is hitting the frame, so looks like i need to c-notch for maximum travel. (not anytime soon)

WHAT CHANGED
Raised the front up to around 32.5 or little less & cut the stops off. Did not add new ones b/c the ones i have linked are too tall for my drop and i would end up cutting them basically all off, so might as well buy new smaller ones. (will edit op with my findings) Also added helper bags to the rear.

Impression

Wow, just that little raise in height and the helper bags have really smoothed out the ride. I did not even change the shock settings. Front 10 & Rear 8 (right now) Once again drove from friends shop about 50 or so miles away, back roads, freeway, construction, etc, rode pretty dang good throughout all terrain and was honestly impressed. Need to adjust rear bags a little and fine tune the height on the front to exact 32, but just that .8 from 31.5 to 32 1/4 has me quite pleased again with the ride. Seems to handle better as well. One note though, it is now a little bouncy, that i think may be from the rear and adding bags, b/c it raised me an inch for some reason.

With that i suppose there is a limit to how low we really can go on our tahoes and still have a comfortable ride that handles well. But dont hold me to that, as i do have an idea, but was told it did not make sense and awaiting a response from someone. But if true, I can go lower than i thought if i wanted to. (will add details when i know what im talking about, lol)

This also may show that even if the ride in front is actually good, if the rear is not equal it can kill the whole comfort of the ride. (at least in my opinion)

Nice writeup. Looking forward to long term reviews to see how well the shock bearings hold up. I've considered this swap quite a bit over the last year or so.

Mike

AWESOME!!!

Do you have any pics of the truck with the new set-up? Would like to see how low it looks.

Glad you like it! One thing I didn't see is a new lower bump stop. I think you said you forgot to order them but I highly recommend installing them at the same time and cut off the old pocket. Great review!

I also didnt notice your cv shaft?

For people asking, I have about 1500 miles on mine with no problems.

is it possible to use this in a lifted setup?

Stance Pix Added

How is the write up / review. Any changes need to be made to make it easier to understand.

M Hankel said:

Nice writeup. Looking forward to long term reviews to see how well the shock bearings hold up. I've considered this swap quite a bit over the last year or so.

Mike

Click to expand...

Thanks, I really was not sure how to write one up as it is not really a install procedure sort of, but thank you. I tend to try to clean it up some when i have the time.

The bearings are steel upgraded ones and much more durable than the poly ones that come with the shocks. Just the feel of them gives a sort of confidence to them.

NathanJax said:

AWESOME!!!

Click to expand...

Thanks Nathan.

Big Buttons said:

Do you have any pics of the truck with the new set-up? Would like to see how low it looks.

Click to expand...

Just added pictures now.
But honestly it looks just like my Tahoe did before the install. I am at the exact height before and after, but man did the ride change.

Atomic said:

Glad you like it! One thing I didn't see is a new lower bump stop. I think you said you forgot to order them but I highly recommend installing them at the same time and cut off the old pocket. Great review!

I also didnt notice your cv shaft?

For people asking, I have about 1500 miles on mine with no problems.

Click to expand...

Yes, i forgot the bump stop, already ordered and we did not even think of cutting the cup off. I am planning on doing that soon. Mostly a ride check right now to make sure all is good and well. But cup is coming off when i put the stops in.

My tahoe is 2wd, so I do not have any CV axles to get in the way. (one less headache, lol)

middelgriff1 said:

is it possible to use this in a lifted setup?

Click to expand...

As stated in the OP, yes to my knowledge I would think so, as your only using the brackets. The main thing is the correct shocks. That is where the length comes from. If i ordered longer shocks my tahoe would be much higher.

Boy did you come through! Great writeup!

Love the detail.

Love the pics.

Love the welds instead of bolts.

Couple questions for you...

What kind of welder did you use?

How much shock travel do you have before something bottoms out?

Have you bottomed out yet in the front?

How much did the springs cost you via ebay?

Do you think you'll need to change out the front springs to a different spring rate?

digitalfiend said:

Boy did you come through! Great writeup!

Love the detail.

Love the pics.

Love the welds instead of bolts.

Couple questions for you...

What kind of welder did you use?

How much shock travel do you have before something bottoms out?

Have you bottomed out yet in the front?

How much did the springs cost you via ebay?

Do you think you'll need to change out the front springs to a different spring rate?

Click to expand...

Good lord son. j/k

1. thanks, Was on fence on write up as you know.
2. Thanks plenty more to come and better when weather gets nice.
3. He did a very nice job on the welds. I made sure.
4. Miller 251 ( if thats what your asking)
5. 11.125 in. Extended & 8.625 in. Collapsed I think atomic said 2.5" either way
6. Nope have not bottomed out yet. (not much driving yet)
7. Springs were around $60 i think.
8. Speaking with atomic, he suggest the 1200 lb spring as he is using it. I do not think i will need to go higher, but time will tell. Right now the ride is awesome and especially with the qa1 adjustables i can tend it to my mood. Stiff or bouncing like an old Caddy. Floating.

Wait till i post up a little vid of this beast hopping.