TRD/ Magnuson 4.0 Supercharger Tips, Tricks, and Mods

My truck is 2005. not sure if there were any changes along the years. but yes, fuel gauge is accurate still for the most part, in that it tells you what is the relative status of your fuel level. I don't know if 1/2 on the gauge really represents 1/2 of a tank, since the tank isn't a perfect cylinder it takes different amount of fuel volumes to change the height of the fuel. But full is full and empty is nearly empty. Although it takes a really long time for the needle to move off full. Since there is soo much room at the top of that tank it takes a long time for the float to start sinking. Then at the end, I notice there is still a LOT more fuel in reserve, due to the huge flat bottom foot print of the tank. Like, when the gas light comes on, I can still drive for a long while, where I'd be concerned with a stock tank... and then only put in 26-27 gallons. I've never run it out, but tempted to carry a full jerry with me and then run it out some day. then pour in the whole 5 gals, and go straight to the station and fill the rest to understand how much the swept volume really is. I wasn't thinking when new, and poured in an unknown quantity for startup and leak checks. the first fill I put in close to 30 gallons, but didn't write it down either so who knows.

 

what sort of changes/compromises would happen with a tank behind axle?

 

Improved handling and traction

 

IMO only, same issues as when you put on a huge bumper with swingarm and tire, Jerrys, jack, etc. The weight acts as a cantilever on the frame behind the axle where the truck is supported at the leaf spring perches. if you box the frame after the axle, it just transfers the flex to before the axle and under the rear portion of cab.

From a physics perspective, adding weight outside of the axle centerlines acts with increased force, like on a lever. Changes the inertia of the movement, pitch/roll moments of the truck, etc. All of that is bad for offroad performance. The inducing of frame flex and the truck being even more ass heavy (for me I'm already heavy as hell with all the gear), is really hard on things, requires much stronger springs, then stiffer shocks, and it is a snowball effect. but some cannot be avoided.

 

I don't agree with that. but it is ok to disagree. Perhaps you could explain your thinking more?

 

Any other interesting revelations that can be posted on a public forum?

 

You ever ridden in a properly tuned leaf spring truck? They all try to keep weight out the back of the truck. Leaf springs by nature do not like to move smoothly like a coil over setup. You are right that it creates a larger moment out the back of the truck, but with leaf springs it almost always results in a smoother motion of the rear suspension. Of course without shocks that can handle the damping you are going to be fighting the motion of the springs. But from an off road ride quality standpoint, when using leaf springs, more weight out back is going to be smoother.

For example when tuning my truck over the last few years, one of the things we did was move the spare tire from the front of the bed to the rear. That 16” or whatever it is, made a noticeable difference in the way the truck handled small to medium bumps. It made such an improvement that as much as I want to change my rear bumper style, I haven’t because the current one is freaking heavy and I don’t want to lose the weight back there.

As for traction, that’s just obvious. More weight over/behind the tires is going to put more force down to the ground at the tires

 

ive got a very light bed area. no spare, at most 300lbs of tools, and very extensive aftermarket suspension. being that mine doesnt get wheeled i thought this may work well for me. and with adding more lift last week i have clearance!

 

Maybe more traction on the rear wheels but it'll cost you traction up front since you are effectively reducing the front axle weight by moving weight from between axles to behind the rear axle.

 

I do sometimes forget that not everyone has a loaded down adventure camping setup: drawers, shell, tent, awnings, water, fridge, camp gear for family of 4, steel swingarm bumper, 35s, lockers, armor, etc etc etc. I'm not even gonna post my fully laden axle weights... cause I don't want to get into that discussion lol.

All I know is that the frame doesn't like lots of weight back there, it can cause frame flex harmonics and bucking that is hard to solve, and when you are really heavy, then even heavier springs and shocks to control it becomes increasingly hard to do. With less weight and no insane heavy bumper on the back, and no frame plating that is in place already, I'm sure the tank setup from JD is awesome. It would improve multiple things, but there is expense with moving weight that you have to comprehend. Not everyone has the situation where more weight 'smooths' out the ride, and not everyone runs their long travel trucks through the woops at speed and tunes for it to be smooth doing so. I've seen the videos from snowsk8air2

Also don't forget that the tank is variable weight... it sloshes and gets consumed. Are you so tight in the shock tuning that it matters? 30+ gallons is NOT light. With gas being 6.3 pounds per gallon, that is way more than your 37" spare tire weighs, and that is just for the fuel swept volume, not counting the tank or the cradle or plating/mounts or pump.

I'd argue that lighter weight (within reason) handles better everytime if you account for it in the tuning and springs and shocks. never heard of an intentionally heavy racecar. Inertia is inertia.

If moving weight made a difference in your truck, then the spring rate (which isn't very adjustable with leaves) wasn't perfect for the truck weight, and you acually needed more inertia when hitting those big bumps so it didn't buck you off them.

 

Well yeah, but you have the engine up front providing plenty of downward force on the front of the truck. You can obviously take it to the extreme and put enough weight out back to significantly lighten the front axle weight. But that’s now what we’re talking about. More trying to balance the weight front and rear by adding rear weight

 

You could be completely right, in a stock ish rear weight of a truck being too light compared to front axle weight. Adding rear to balance inertia a little better could be good. I see that point. But not very applicable to a full loaded camping rig, that will never see air time, long travel, woops, or general high speed running through rough roads.

 

Yes but you were saying that adding weight to the rear is bad based on your rigs weight distribution. I know mine is on an extreme side and everyone’s truck is different. But I’d say 90%+ of the trucks out there don’t have a constant 800lbs in the bed. Which is where I was coming from stating that adding weight out back is usually going to help. And we can take it down the rabbit hole in any direction, I’m just saying in general, a leaf spring truck is going to see improved off road performance with some extra weight behind the axle helping things move more smoothly

 

Good points. I can agree to it. the idea that if the rear is light (mostly empty bed, no major extras) than more weight behind the axle will help with more rear inertia which will feel smoother (but also bottom out easier with a given spring rate). And behind the axle will slightly lighten the front load but not by much as stated, both better for the issue you are solving. For people carrying camper shell, camping gear, RTT, water Jerrys, awnings, and the like, weight between the axles is better than behind the back axle.

And yes, I think both our trucks are on the extreme side of things, although opposite directions. I wish the rear axle only had 800 pounds additional!

 

Mine will be similarly set up. Dual swing out should be here in the next couple weeks. That plus the camper and everything else, it will definitely be heavy in the rear. I plan to get the leafs re-arched again for the newly added weight of the bumper.. The weight definitely helps smooth things out.. and was dramatically noticeable when going up to the PNW to get our camper. On the way up without it.. stiff rear end.. after camper.. back to "normal", as that(payload) was what the leafs were arched for. My 13g water tank is a flat tank in the bed up against the cab.. I wanted that weight as center and low as possible. the rear weight of a swingout is a given. no way around that when needing to carry a 35" spare and other goodies. So it is what it is.

 

It's all about balance and suspension components that work with your setup.

With 2 spares, a HC rear bumper with a swingout, a shell, and often a RTT, I make a point to load heavier gear into the front of the bed when packing for a trip. I can definitely notice the difference between 200lbs at the front of the bed vs at the tailgate when I stretch the legs a bit in the desert.

 

At this time I don't have anything more to share other than just the pictures. Not because I'm with holding, but I just haven't moved forward with the project.

I have been a bit occupied with my Jeep and HPTuners at the moment as well some some 3rd Gen tuning developments.

 

Looky looky.

 

New 1GR Quantum Solenoids installed, on @Lucario Runner 's truck. Soon to datalog, after diff install.

 

What info is available for the diff?