Belly Tank Build Diary

[Mike Brown]

To guide the hole saw I clamped a piece of 1/4" steel that I had cut with the hole saw to the rib that I was cutting. 

[Mike Brown]

I then proceeded to cut the rib with the hole saw assembly in a drill. 

[Mike Brown]

This methodology worked well (and safely) with a photo of the finished cut attached.   

[Mike Brown]

I decided to install a panhard rod.  There is not a lot of room inside the belly tank but I didn't want it hanging out in the air.  This necessitated a shorter than desired panhard rod but with a very short suspension travel would be satisfactory.  I used the same methodology for the panhard rod that I used for the other suspension links, consisting of 3/4" rod ends direct threaded into 1-1/4"OD 3/8" wall DOM tube.  Each end was bored and threaded 3/4-16, left and right hand threads for maximum adjustability.  A photo of the link attached.   

[Mike Brown]

I wasn't sure that the panhard rod would work without binding and I am hesitant to weld mounts to the frame at this point as disassembly for service is getting more difficult let alone cutting brackets off of the frame.  There is also so little room that it just made sense to bolt the mounts to the frame and rear end.  The mounts were made from 1/4" and 3/8" steel.  I installed the mounts and link and was pleasantly surprised that there was no binding of the suspension as it went through its travel.  The Satchell style four link does not technically need a panhard rod (maybe for the street) but with slicks and a spool in the rear end it will definitely stabilize the lateral movement of the rear end and keep the new shocks from hitting the frame rails. 

[Stainless1]

Good work... yep the last thing you need is a steering input from the rear.

[manta22]

Before you install a Panhard rod, have a look at a Watts Linkage to locate your rear axle. Properly installed it solves the Panhard problem.

[Stainless1]

Neil, look at the picture again... not sure he has room for a Watts.  The panhard is just suspenders for his belt anyway.  I'm not a fan of panhards, but it looks level and his suspension movements are small. 

[manta22]

Neil, look at the picture again... not sure he has room for a Watts.  The panhard is just suspenders for his belt anyway.  I'm not a fan of panhards, but it looks level and his suspension movements are small.

I can't tell from those photos how level it is.

[Rex Schimmer]

I agree with Mike that his suspension design does not require a panhard rod, and   it becomes redundant. Now with the high mounting of the panhard rod and the mounting  position of the upper angled control rods both are trying to set the roll center for the rear end. It appears that they are both pretty close to being in line with each other which is probably why the suspension does not bind.

An option would have been making the upper control arms into a ridged "A" arm with a single ball joint connected to the differential and the panhard rod would not be needed and you would have one less Heim joint.

Rex

[Mike Brown]

I agree with Mike that his suspension design does not require a panhard rod, and   it becomes redundant. Now with the high mounting of the panhard rod and the mounting  position of the upper angled control rods both are trying to set the roll center for the rear end. It appears that they are both pretty close to being in line with each other which is probably why the suspension does not bind.

An option would have been making the upper control arms into a ridged "A" arm with a single ball joint connected to the differential and the panhard rod would not be needed and you would have one less Heim joint.

Rex

I agree with you Rex, if I were to do the rear suspension all over I would probably choose a 3 link design with a torque arm.  At this point I just want to protect my very expensive double adjustable shocks.  The suspension is still about an inch up and down.  The side to side displacement of the rear end with the 9-1/2" center to center pan hard rod (which is level at ride height) is less than 1/16" of an inch according to my calculations.  The pan hard rod is very close to the height of the top links which helps to keep the roll center manageable.  The small amount of suspension stroke is the only thing that makes this unusual combination work. 

[Mike Brown]

A photo of the rub marks on the original Monroe shocks.  Between the rubber springs lacking compliance, the rubber spring mounts bottoming and the shocks rubbing on the frame the rear suspension was a mess.  I hope to have all this corrected and greatly improve hooking the horsepower to the track this Spring. 

[Mike Brown]

To help prevent the QA1 shocks from contacting the frame I relocated the bottom mounts inward about an inch.  The compression and rebound adjustments are easily accessed. 

[Mike Brown]

A view from the top of the QA1 shock mounted. 

[Mike Brown]

When I run at side by side drag races (including in the dirt) my launch has always been very slow.  I need a foot on the brake to keep from rolling into or out of the staging lights.  This requires me to then come off the brakes, engage the throttle and release the clutch.  For this season I added "roll control" which is a solenoid that will electrically hold the front brakes on after they are engaged.  I am using the same button on the steering wheel that I will use to activate the nitrous.  I will not use nitrous in drag racing nor roll control at land speed events.  I attached a photo of the solenoid plumbed in after the master cylinder for the front brakes.  On my car the front brakes are separate from the rear brakes activated by a hand lever on the left side of the cockpit.  It will be interesting to see how well my reaction time improves.