sub'd this is a rad build!

 

I scored a Hydroboost and master cylinder off a wrecked '04 Tahoe at the wrecking yard for $40, it even came with one of the hydro lines, I'm going to hold off installing it until a later time.. I did upgrade the rear brakes with the well published SUV rear brakes upgrade..

The difference between the two is impressive.. The rotors go from 12.8" to 13.0", but perhaps the most impressive upgrade is the pad sizing with the use of the rear calipers that upgrade from a single piston to twin pistons allowing for the larger pads...


Twin Piston Caliper upgrade to replace the single piston Silverado stock unit.. Painted up with silver caliper paint and black semi-gloss on the support frame.



Here is a comparison of the stock (worn) pad and the new replacement '07 Tahoe pads (new).



Here's what it looks like all completed and installed, I just need to bleed the brakes and then it's driveable again:






I have about $225 into this upgrade, in all honesty, I needed new brakes anyhow. The rear rotors were SHOT, they were less than .750" thick, as a comparison, the Tahoe rotors are over 1.250" thick. The pads were cracked and tired, I could have gone totally cheap and just done rotors and pads, but this upgrade is a hard one to pass up for the money invested. The fron't will be up next, probably also going with Tahoe or Suburban rotors/calipers/pads on that. That will yield a larger rotors as well..

Here is a list of parts I had to complete this swap for the 100% bolt in.

These parts are from Advance Auto, but Advance merged with Carquest here and these parts were actually Carquest parts:

1ea 18B4764 twin piston left rear caliper)
1ea 18B4765 twin piston right rear caliper)

2ea YH145441P rear rotors 13.0" diameter
1set PXD834H rear SUV ('07 Tahoe) brake pads

 

Nice build Todd!

I know this is 'racetruck' but how does it ride just driving around with the 1200#/225# spring rates?

 

I'm pretty happy with it to be honest, I can adjust ride height up or down from where it is now, so there is that adjustment if I need to make changes.

The coil-over shocks are the Dual adjustable Vikings, so I can tailor compression/rebound.

In all honesty, the rear is probably a little soft for some people, especially if you plan to haul. However, if you drive around unloaded its good; no more annoying jarring and sidestepping that are common on a leaf spring suspension.

The key on my setup is I have rear airbags to help when I want to carry a load. With the airbags fully deflated, I was running into issues with the axle bottoming out because the springs are soft and the roads here in Western TN are total garbage. I have started to put about 10-15 psi in the rear bags and the bottoming out is non-existent; the ride stiffened up a bit, but it's not terrible. I'd recommend a higher spring rate for the rear if you didn't do the airbags, it would just be to hard to live with with them this soft. The good news is, for autocrossing I air them completely down and the rear end is very compliant and planted, even in corners I suspect I have the 4 link to thank here, it's changed the whole dynamics of this truck and how it corners with the coil-overs.

For the front, I certainly wouldn't go any lighter in the spring rate department. I haven't had the front end bottom out, it does feel very compliant and planted, without all the laziness that the torsion bars had. I would be very cautious, at least on my truck, about going to a heavier spring, I cant see it improving the ride any. The big telltale will be when I get a swaybar setup installed. I also want to get a second set of wheels and put race rubber on these wheels when the current tires expire. Undoubtedly this will change the characteristics if I go with a 20" wheel (and less sidewall) when that happens, but for right now I am very happy !

 

Thanks for the info!

"no more annoying jarring and sidestepping that are common on a leaf spring suspension."

I think this is the biggest complaint I have with my current setup as well. May have to reach out to JSM about that 4 link set up.

 

I see you're in Little Rock, do you ever get to any SCCA events? They run in LR at the War Museum, and in Blytheville @ the airport.. I'd take you for a ride so you can see how much better it rides, it's not even close to stock. The last time I ran, I finished within times that were close to a 5th Gen Camaro that was in my class. I suspect with a few more driver mods it may have been a better outcome. I am no where near done modding this truck so times will hopefully improve, I truthfully believe it can hang with a 5th gen Camaro for sure and surprise many other cars along the way. Right now I am still on street tires and stock swaybars with a stock 156K mile 4.8L.. I see only improvements coming !

As far as contacting JSM, I'd recommend it. It's not some huge corporation; JSM is literally two enthusiasts that have been building competition suspensions for years. If you place and order and have problems, you'll get answers and support after the sale. I will tell you that you can get a 'universal kit' for cheaper than the JSM kit, but that is a lot of cut and pasting to make it work. This kit is overbuilt to handle high HP builds and it's tailored to the Silverado/Sierra.

 

War Museum...lol! It's War Memorial Stadium, a college/high school football stadium. Most of the auto-xers refer to it as war Miata b/c the lot is small and geared towards small cars. Yes, I've ran there years ago but never at Blytheville. So yeah, if you're ever in Little Rock to auto-x let me know, I'd come out to catch a ride.

I currently have Ridetech strong arms up front with their HQ coilovers and 700# hyperco's. It'd be nice to have something in the rear to complement that.

 

That's cool, sorry I've never been there myself. I was at work and shooting from the hip on the location. The ARSCCA group has an event coming up, but I am already going to the Grenada MS event on the same weekend. I had heard it was a tight venue and I assumed it would be Miata and Mini-Cooper heaven, LOL, Fullsize Silverado = Cone Murder. I ran on a small lot up in Indy when I was running with Indy Region, they are still fun, perhaps the truck would do OK on a smaller event ? I dunno, that location is almost 3 hours from me so I probably won't attend it often.

I am interested in how you are able to get away with 700# springs on the front of your truck, I had 650# before I went to the ones I have now. Running the 650s it was compressing them almost entirely.. How does your truck ride? Does it handle the bumps OK? I was totally smashing the front end when I drove into Memphis, so I had to up-rate my springs. When I did the math it came out to around 1275# recommended spring rate and I went with 1200# to be safe.. Are you still running the stock sway bar ?

 

No problem on the venue name, I just got a little chuckle out of it for some reason. I'm with you, large or small, they are fun once you get out there and get involved.

As far as the spring rates go, I used Ridetech's online calculator and input the most accurate data I could and it came back with 600/650/700 so I erred on the heavy side since most of the conversions I saw on this site were running 1k# rates more or less. With my truck being 2WD I have a little less weight than you and I'm sure the geometry of the Strong Arms is different than your factory control arms so, there's that for whatever it may be worth. The front end is fine, way better ride than the 2" Hotchkiss drop springs and Edelbrock IAS shocks that were replaced! I'm sure if I got into auto-x with it, I would for sure need/want higher front spring rates but for DD it's fine. I have the Hotchkiss sway bars front and back from their old TVS kits as the TVS 2/4 was my first attempt at lowering my truck.

 

Hey Guys,

Just and update, its been kinda crazy here lately so I haven't been doing as much with the truck as I'd like to, well at least not FUN things.

We had a pool installed and I've been trying to get the yard back to some sort of normalcy since then so unfortunately, I've been doing truck things with my autocross toy..



and



The truck has taken it in stride. I just max out the airbags at around 110-120 psi and it just takes it. The brakes have been a welcomed upgrade for sure when doing this.. When I am done, just let the air out of the 'bags and I am back to a smooth riding truck.

It hasn't been all work and no play, last weekend we had a local SCCA event that I went to and competed. It was soo damn hot out, the heat index was north of 110*... That's a long time to be standing out in a parking lot ! So I was looking for some shade, anywhere to park the truck, overall it was still a good time.




I ordered some PAC1218 springs from eBay, they came in yesterday. I'll try to get them on the truck soon and order a Sloppy Cam and start working on re-tuning the truck.

Then it will be decision time, do I go turbo kit and risk annihilating the 4L60e or do I take the safe route and start on the 4L80e I have sitting in the shed ??? Haven't decided yet..