Mazzulla kit/coilover questions.

chatter_splatter

Well-Known Member
Posts
89
Reaction
24
Hi all! New to the forums and also new to owning a desert truck. I've worked in the off road industry for a few years as a welder/fabricator so I decided it was time to pick out a truck and start going fast.

It's been a learning experience.

The truck is a 2006 Silverado 5.3 with a Gen 1 Mazzulla race kit, 2.5x10 fox coilover/double bypass up front, and a Ford 9" under deavers and fox 2.5x16 double bypasses in the rear. 37" tires on 17" method standards. Double spares, 32gal fuel cell, and a bedcage.

She's been rode hard and put up wet and I'm in the process of rebuilding everything. New bearings, rod ends, bushings, sleeves, hardware, shock oil/seals/wearbands, tires, everything.

I've come across quite a few things that need to be addressed.

Springs: Primary is 18" 850lb/in, tender is 6" 600lb/in (way too tall). Crossover rings got loose and worked to the top of the coilover, so the 600lb springs have been in coil bind for a long time and nobody corrected it. Possible main coil bind. Ruined the preload rings as well as the spring dividers. Luckily the coilover bodies are still ok.

Shock valving: Seems to be in the ballpark. Coilover is 50/70, bypasses are both 2-1/70.

So, one thing I know about the Mazzulla kit is that it has a fairly large motion ratio somewhere near 1.8 to 1. This means that the truck needs a really heavy spring. Chris himself told me 800lb/in was standard. This makes sense because my sprung weight up front is around 1250lbs per corner. This means each spring is supporting about 2250lb at ride height.

So here are my questions:

A reliable source told me I should shoot for dual rate to soften up the chatter. He might not have realized the packaging and rate constraints on my application, but could be possible with a couple options.

16" 800lb/in primary, 8" 600lb/in secondary (can't find an 8" spring any stiffer). This could work with some preload, but it has a huge rate spread.

Two 12" 700lb/in springs. Probably still too soft and will still need some preload, but the rate transition will be smoother.

Leave it alone and stick with the 850lb/in primary with a shorter tender.

I've done some research and it seems like all of the above spring configurations will "work" but I really don't know enough about long travel coilover design to pick the best option.

The truck sees pavement, but let's just assume it doesn't. I got it to use on trails and desert, and that's where it needs to perform. As far as tradeoffs, I know a dune truck and a trail truck are going to feel different, so I'm doing my best to be somewhere in the middle. In short, I want it to handle chatter without knocking teeth out and see a couple feet of air every now and then but nothing crazy. Hydrobumps and possibly longer shocks up front/four link rear are in the future, but out of the question for now.

I took the truck out to Geiser Loop near Phoenix last week and realized how much attention it needs.

I'm here because I need all the advice I can get and this seems like the best place to start.

Thanks in advance!!

-Will
 

Bert is my name

Well-Known Member
Posts
906
Reaction
338
If the truck isn't over built and heavy I would start with mazullas recommended springs and valving. Tune from there. Check the classifieds for lightly used springs to save a few bucks if changes are foreseen. Go to a test and tune day if your shock manufacturer has one.
 

chatter_splatter

Well-Known Member
Posts
89
Reaction
24
If the truck isn't over built and heavy I would start with mazullas recommended springs and valving. Tune from there. Check the classifieds for lightly used springs to save a few bucks if changes are foreseen. Go to a test and tune day if your shock manufacturer has one.

The trucks sprung weight should still be close to stock. Shocks and towers probably didn't add much weight. Mazzulla recommended an 18" 800lb primary spring with a 6" 500lb tender. Chris also said that the valving is pretty "middle of the road" which is what I'm trying to reach. I'm just wondering if trying dual rate coils is possible on 10" coilovers and if it would be worthwhile.
 

chatter_splatter

Well-Known Member
Posts
89
Reaction
24
I ordered a 17" 900lb primary and 8" 600lb secondary today. The numbers look good on paper but I won't know for sure until they are on the truck. Should be around 360lb/in until the 900lb spring hits the crossover ring. Hopefully this will allow enough room to get the bottom 10" of travel fairly soft, with the last 8" being pretty firm. Should need about 1.5" of preload. We'll see what happens!
 
Top