Front coil over kit. Thoughts?

[Paul Y]

Afternoon gentlemen,

Idly parusing the internet and come across this kit from CPP

https://classicperform.com/shop/6387cok-2a550

Has anyone used/fitted/planning in using this kit?

Compared to others it does seem at the budget end - admittedly there is no lower control arm - so would be interested to hear real life experiance befoer I add it to my 'want' list.

Over too you.

P.

[theastronaut]

What is your goal for the truck? Better ride quality? Better handling?

I posted this in another similar thread yesterday-

Originally Posted by theastronaut

Spring rate is spring rate, it doesn't matter if its a separate coil and shock or a coilover. Same goes with shock valving- doesn't matter if its separate or combined with the spring. A lot of people hear "coilover" and automatically think they're a magic pill for making it ride and handle better, but they mainly just make it easier to change spring length and spring rate (desirable on a race/track car) and ride height/corner weight adjustments are easy to make.

The stock spring rates, or drop spring rates available to fit in the stock pocket aren't bad as-is. The stock shock geometry isn't bad as-is either unless you're going super low, so switching to a coilover won't really improve either of those aspects.

A good quality double adjustable shock in the correct open/closed length for your ride height will do about 90% as much as a coilover can do for ride quality, if the coilover shocks are also adjustable. You just can't adjust ride height or spring rate as easily, but how often do you need to do that on a street truck?

Another thing you often lose with coilovers is suspension travel. Trying to stuff a coilover in the place a coil spring was means you lose travel, and you need travel to have good ride quality. To compensate they usually raise the spring/shock damping rates to make it stiff enough that it won't bottom out, but that makes it stiff all of the time.

My autocross car has coilovers, but they're set up with pretty low spring rates (125 lb front, 105 lb rear, 1720 lb curb weight) and they have tons of travel so it still rides pretty nicely. The shock valving is vastly better than the original struts so its able to corner a lot better from the wheel motion and body motion being much better controlled.

If you're not chasing lap times and aren't wanting to adjust the ride height often, a set of drop springs and adjustable shocks will get you where you want to be with ride quality and handling improvements, then you could spend the money you saved on sway bars and a better steering box like DSE or Borgeson to improve steering feel/response.

[SCOTI]

Originally Posted by theastronaut

What is your goal for the truck? Better ride quality? Better handling?

I posted this in another similar thread yesterday-

Agreed w/this info 100%. Facts are facts.

[Paul Y]

Apoloigise for the late reply.

I would like to get the truck to the point where it handles competently hence the front annd rear ARB, shocks, relocated lower control arms and chassis brace.

After consideration, the lure of the coil overs is the ability to quickly and easily set ride height. With the added benefit of being able toplay around with spring rates.

Admittedly, a better option woud be an upgraded sterring box - I have a Red Head box that feels really nice in the limited driving I have done so far but the turn to turn is... supertanker'esk!

Just looking to see if anyone has used this system.

P.

[theastronaut]

Unless you're chasing lap times, the spring rates as-is are probably 90% as close as the need to be, maybe less in the rear would be good if you're not hauling anything. But shock valving plays a much larger part in handling than spring rates.

I have relocated rear shocks and D2600 bags in place of the springs in the rear of my '66, which lets me set ride height easily and I can add air when hauling as needed. I just have a couple schrader valves behind the licence plate, no compressor or tank- simple, easier to adjust height than coilovers, and can be pumped up for hauling/towing. Even though it doesn't have sway bars at all, it corners flatter than my autocross car- the shock valving and having the shocks in a location that works best keeps body motion under control. Sway bars should be viewed as a secondary means of controlling body motion, not the first line of defense.

"Handling" is a very broad term and everyone has a different definition. I was on another forum last week and a guy with 4" of steering wheel play and bloated/floppy sidewall 265 wide tires on 6" wheels said his truck "handled great" in a thread about restomods... So it's important to figure out what you want out of the truck and which parts are needed to improve "handling".

Just taking out body roll doesn't mean it goes around corners faster, as my autocross car leans pretty heavily (it pulls one wheel off the ground) but pulls 1.4g+ and regularly places in the top ten overall with only about 80 hp. Another of my cars from the factory is set up so softly with spring and shock damping that it feels floaty but will go through a slalom as fast as a modified Miata that has zero body roll. If you want it to "feel sporty" then most people associate firm/overly stiff suspension with that, and little to no body roll, because that's supposed to be what "handles good", but stiff doesn't soak up bumps. I had a modified miata on coilovers and it would skip sideways over mid-corner bumps if you were pushing it, and would beat you to death all the time- too stiff and not enough travel. You need travel and compliant shock valving to soak up bumps on the street, and a lot of coilover conversions run out of space to use long travel shocks that can soak up bumps. If its' skipping sideways over bumps when cornering then it's not handling well, even if it "feels sporty".

Much of the entry level aftermarket pro-touring/restomod suspension parts are going to make the truck "feel sporty" so you tell your friends how much better it "feels" so they go buy more of their parts, but won't add all that much extra grip- that's the job of tire compound, suspension geometry, shock valving, and having enough travel and compliance to keep the tire firmly in contact of the road without bottoming out over bumps. The stock front suspension has pretty good geometry (if you're not chasing lap times), plenty of travel, spring rates that aren't bad, and there are shocks and shock relocation kits that will have much more travel than any coilover that fits the stock crossmember.

[SCOTI]

Originally Posted by Paul Y

Apoloigise for the late reply.

I would like to get the truck to the point where it handles competently hence the front annd rear ARB, shocks, relocated lower control arms and chassis brace.

After consideration, the lure of the coil overs is the ability to quickly and easily set ride height. With the added benefit of being able toplay around with spring rates.

Admittedly, a better option woud be an upgraded sterring box - I have a Red Head box that feels really nice in the limited driving I have done so far but the turn to turn is... supertanker'esk!

Just looking to see if anyone has used this system.

P.

I've read many of your posts throughout your build thread. Could you provide a list of the suspension mods you've done relative to this thread discussion for quick & easy reference?

What shocks front & rear? Stock locations or ??

What sway bars?

What chassis brace?

What tires/sizes front & rear?

You mentioned the steering box so a fresh box w/a better ratio sounds like a great plan. What about your current set-up do you feel makes it currently less than what that C/O kit might provide to improve competency/performance?

[Paul Y]

Scotti,

Busy at work so again apologies for the slow response.

Chassis upgrades are all from Rob at No Limits

Front ARB is 1 1/8th with poly bushes and rose jointed drop links

Rear ARB is 1' - I think as it has been 10 years since i purchased the kit!

Panhard bar kit from No Limit

Rear shock remounted to outside of Chassis

Front shock mount raised

Front and rear shock are Doetsch Tech - In hind sight probably too stiff

Lower control arms moved forward 3/4'

Front springs are 1 ton with 2 coils trimmed off

Summit racing frame stiffener.

Tyres are the weak point as I am running generic 235/75/15 at the front and 275 60 15 on the rear. This is for cosmetic reasons.

As the weather is still...poor... here I have not done any real road testing as yet so comment on the steeting box is based on my initial driver in and oiut of the gates.

I am going to look seriously at adding rear bags as I still want to use the truck as a truck. The current springs are great for ride height but not great for load carrying capability!

P.

[SkinnyG]

That sounds like a perfect setup for a daily-driver/toy to me. You have my blessing.

Good call on the 1-ton springs; they are a very decent spring rate to ride low. I had them in my '77 Silverado, and I will run them in my '61 if and when I ditch the air ride.

[SCOTI]

*Front ARB is 1 1/8th with poly bushes and rose jointed drop links
*Rear ARB is 1' - I think as it has been 10 years since i purchased the kit!
*Panhard bar kit from No Limit
*Rear shock remounted to outside of Chassis
*Front shock mount raised
*Front and rear shock are Doetsch Tech - In hind sight probably too stiff
*Lower control arms moved forward 3/4'
*Front springs are 1 ton with 2 coils trimmed off
*Summit racing frame stiffener.

Tyres are the weak point as I am running generic 235/75/15 at the front and 275 60 15 on the rear. This is for cosmetic reasons.

Nice selection of parts integrated into your set-up.

The front & rear sway-bar tandem is great. I've always used the GM HD truck 1.250" solid bars, but would wager the NLE spec'd 1.125" is right in the ballpark. I only like the use of a rear bar based on what truck-arms & bushings are in place. Aftermarket solid-tube style arms w/poly bushings? Def no rear sway-bar for me as I feel it's one big bundle of bind. OE truck arms/bushings? I'd try a rear bar. With your factory T/A's seams stitch welded & the fresh Poly bushings, I think you landed on a combo that should still allow decent articulation vs bind. Too much bind impacts ride quality.

I like the logic of increasing distance (up/down) for the front shock mounting points. With 2-coils removed from the spring, travel was reduced & raising that upper mount helps. That being said, I went back & looked @ your build images of the front to have a refreshed view. The lower arms were moved .750 forward.... What about the shock mounting location in regard to that change? It actually looks slightly behind the original mounts location. I'd want to ensure the shocks aren't angled too much as it will possibly impact compression geometry. For the ones I've done, I recall moving the lower mount position to the rear of the original a-arm bracket (to offset the forward relocation of the arm) & I made my own upper bracket as well (to also better align the shocks upper/lower mounts vs. stroke).

I also like the logic behind the relocation of the rear shocks for these trucks (better leverage when placed outboard + better possible travel geometry) and is a big difference vs the OE arrangement. That being said, I DO NOT care for NLE's rear shock mounting arrangement. It seems weird to use a shock mounting direction that doesn't compliment the arc of rear suspension travel (bind free travel). Since the rear end can move slightly side to side during travel, I feel the pivot axis for the shocks should follow the same path. NLE's are 90° different @ both top & bottom. Is that a big deal? IDK, but it seems mounting things to pivot on a similar arc/direction would yield a better result. Again... It's quite possibly a moot point as IDK which changes more (wheelbase vs. side shift with up & down suspension travel).

As far as the shocks? I've never used the Doetsch Tech brand so I can't speculate. I like Bilsteins on my C10's so that's my go-to (I've run them on my other vehicles as well). If you feel the valving seemed right, then I'd guess you're ok there.

Tire size choices seem fine. The fronts aren't ideal for corner-carving but will still work well enough to enjoy spirited drives. I have 225-75-16's on my dually (OE steel 16x6's) & I'm not scared of faster paced corner entry/exits.

One thing I didn't see mentioned are alignment specs. They make a difference when dialing in drivability (for spirited driving).

[Paul Y]

Again, thanks for the feedback.

I used the instructions from one of our illustrious members re rear shock relocation, flipped the lower shock mount and fabricated a stand off to give me clearance and height to allow the shock to move.

Good point on the pivot, would the bushing not absorb this rotational movement?

As for alignment spec you beat me to the punch line! I have no idea at the moment so was going to enquire if there was an alignement spec you would recommend?

Hopefully will not be a week before I respond next time!

P.

[SCOTI]

Originally Posted by Paul Y

Again, thanks for the feedback.

I used the instructions from one of our illustrious members re rear shock relocation, flipped the lower shock mount and fabricated a stand off to give me clearance and height to allow the shock to move.

Good point on the pivot, would the bushing not absorb this rotational movement?

As for alignment spec you beat me to the punch line! I have no idea at the moment so was going to enquire if there was an alignement spec you would recommend?

Hopefully will not be a week before I respond next time!

P.

The bushings can absorb the movement but my bet is they'll wear faster.

Target .5 NEG Camber.

Dial in as much Caster as possible w/o impacting the .5 NEG Camber. Originally these trucks might be in the POS 1-3° range. With the lower arms forward, you should be able to get in the 5-7° range.

Minimal Toe-In.

[Paul Y]

Thanks Scoti,

I am doing a home alighnment this weekend and will be going to my friendly alignment shop once it stops raining here.

Will report back once I have it dialled in.

P.