Belly Tank Build Diary

[Mike Brown]

Minimum tension on an 8 rib Micro-V belt after break in is 80 pounds. So your going to make a break in fixture for the belts? Data sure works my data shows a spring tensioner allows us to get 18 pounds of boost turning 6500 engine RPM blower RPM just under max allowable. No slippage  equals lots of very fast speeds and records.

From Gates, "After a short run-in period, tension may drop and require re-tensioning".  I will run-in the new belt at Kilkare, a 1/4 mile dragstrip.  I will check and retension as necessary between passes.  I prefer testing in situation verses on the bench. 

[Mike Brown]

I have SFI 45.1 roll bar padding.  Is it legal to wrap the padding with flame retardant tape like, Polyken 268 Flame-Retardant Wire Harness Tape?

[Mike Brown]

I purchased a pair of Mickey Thompson DOT drag radials for the mile land speed events.  There is a warning on the Mickey Thompson site that running the tires on a dyno voids the warranty.  The label on the tires after I purchased them said that race tires have no warranty.  I made three passes on the tires at the Arkansas event, no burnouts and no dyno time.  I noticed that there were diagonal patches on both tires that had no scruff marks, this section of tire never made contact with the track.  The car handled differently on the big end of the track. 

[Mike Brown]

I went online with Jegs where I purchased the tires and started a "chat".  I asked the same questions and attached photos.  They told me that they would replace the tires.  I drove (1-1/2 hours) to Jegs this morning.  The counter person told me that Mickey Thompson tires had no warranty.  I explained the chat and promise of new tires.  They not only replaced the tires but they mounted and balanced the tires in their tire shop.  They didn't charge me for anything.  It was refreshing to have someone stand by their promise and gives me caution when purchasing to insure the manufacture covers obvious manufacturing defects. 

[desotoman]

Mike,

Thanks for letting us know about your experience with Jeg's. It is aways good to hear about companies who honor their word, and work with the buyers of what they sell.

Tom G.

[Mike Brown]

We took the car back on the dirt at the KOI drag racing event at the Hartford Fair in Croton Ohio.  Not my jam so much but just another opportunity to run the car and gather some data.  I was specifically interested in the front and rear tire speed after changing the location of the Hall Effect sensor from the driveshaft to a rear wheel.  It is a short run (typically less than 5 seconds) at 200 feet.  I use first gear only and from the this run you can see (top yellow line) the rear tires were slipping mercilessly with a speed of 62mph while the fronts were registering less than 10mph.  The good news is that the front and rear tire speeds match for a lot of the time as I was going slowly back to the pits.  I can now get good data regarding rear tire slip while at a mile event.  I was evaluating "roll control" with the front wheel brakes so that I could stage while in first gear with a little higher rpm for the launch (I did not need a foot on the brake to prevent slipping in or out of the lights).  The bad news is that I just don't have enough traction with the hand grooved tires to put much horsepower to the track, so I just blow the tires out using the roll control.  I had better results leaving easy and rolling on the throttle.   

[Mike Brown]

I am back on the pursuit of increased rear traction using a wing.  Extrapolating data from the manufacture (I know that this is not a very accurate methodology, but I wanted to start somewhere) my narrower wing should produce 536 pounds of downforce set with zero degree incidence.  I chose to mount the wing on a pylon forward of the rear axle.  This will allow 28% (150 pounds) of the weight to go on the front wheels negating the affects of drag which wants to lift the front wheels.  Accurately setting the wing angle during fabrication is complicated as this is the angle from the rear of the wing (bottom of the Gurney flap) to the center of the leading edge.  Photo supplied for clarity. 

[Mike Brown]

I cut out a block of wood and machined the top flat to allow repeatable measurements of the wing incidence. 

[Mike Brown]

The wing is mounted on a pylon.  The pylon began with a heavy wall tube faired with 3" wide sections of 11ga steel.  The mount is 1/2" steel that attaches to the upper chassis stiffeners.  The wing is on one steel plate fastened to a second plate with socket cap screws so the wing can be easily removed.  The wing is just lying on top of the pylon for illustration purposes in this photo. 

[bubruins]

Smart. Love seeing these forward of the rear axle.

[Mike Brown]

A friend of ours recently had a business destroyed by fire.  The fire was caused from an overheating LiPo battery being charged.  I took a page from Mike Wagner's (of Cornfield Customs) playbook.  I ordered a flammables cabinet ($100) from Amazon.  I added a power cord using a cord bushing through a hole drilled in the bottom.  I will store and charge my LiPo batteries in this cabinet. 

[Mike Brown]

A photo of the cabinet with the door closed.  They come in all sizes. 

[Interested Observer]

Since you are putting energy into it, what keeps the cabinet cool?

[Mike Brown]

Since you are putting energy into it, what keeps the cabinet cool?

That is a good observation and question.  The cabinet that I purchased has two bungs (can be plumbed to the exterior of a building if desired) with screens for fire resistance.  I will track heat gain with a thermocouple to see how much the temperature rises over ambient and be sure to not exceed the manufacturers rating.  A bigger concern this season for me is charging when it is cold.  LiPo batteries won't charge below 32 degrees F.  I only heat my workshop when I am using it.  If the temperature is too high in summer months, I will add a small "pancake" type fan to help circulate the air. 

[Rex Schimmer]

Mike.
Always a pleasure to watch your latest mods to your lakester. Love the wing idea, what are the dimensions of the wing section? It looks like an extruded section, who did you get it from? I might suggest that you cut the wicker bill off and make it so that you can add wicker bills of different heights. I like the mounting "post" you can make it pretty aero with some shaping and you have lots of material to grind out a nice shape. I am sure you thought of maybe using some of the commercial aero tubing but the price is very restrictive, $106/ft for the 3 3/8 inch stuff! We used some for our front axle, had to put a piece of 1-3/8 1/8 wall tubing through it to make it strong enough.

Keep up the good work, looking forward to seeing your mount and adjustment mechanism.

Rex