So I always try to share my experiences so hopefully it helps other avoid or have a solution to similar issues.

About 1/2 way thru this season my reaction times and car variation both started acting up. My reaction times went from very consistent <.020 to an occasional .05X-.08X. You might recall I even had a post. Consulted with people like my trans builder etc. Thru this time we went thru various checking of items - sending box to KR that is always helpful and even looking in the mirror at myself as the problem. But those of you that race a LOT - get a good feel when your late. And when you think your pushing a double O or red and get an 080 and car seems to leave late you know something is up.

As the season progressed and things were checked. You find little thing that while in your garage you swear have to be the problem - only to go to the track and find the gremlin is still there.

My primary early symptoms were: occasional late reaction, and car would move .015 to .02 occasionally. Later in the season about 3 weeks ago - my trans started acting weird when I would put it into second at low speeds thru the pits. I pulled it apart and found right away that the seals were pinched and somehow they lasted like that for almost 200 runs exactly since last seasons rebuild. The high speed clutches however looked perfect and that told me the little bit of variation was not likely from the seals and this problem was just another issue that was generated. I rebuilt the trans while watching my buddies race at Norwalk and knowing with the problem I would be donating money if I had gone. As I did several other money races - get to the 4th or 5th round and have a 080 pop up - when otherwise you were .000-.012 on all other hits. Trans is fixed - pressures all good and trans feels fine. Show up for last points race before bracket finals. Go to test and tune and now the car is running 122mph on run, the next run its 117 and back and forth we go. I am starting to actually be able to hear the motor as I drive to the lanes sound different. And am dialing off what I hear. If you look at the slips for each mph the car is a zerox machine putting up runs within .000X. The next day I come out of the motorhome to rain and see only two other rigs in the area. Before I emerge I have resigned myself that it has to be ignition ( I have already changed wires, cap, plugs everything imaginable) - one thing except the grid. So I order a grid but that isn't going to do me any good for points race that day. I walk over to the rig where some guys are hanging out and ask if they might have a spare grid. The guy says yeah I have two of them! Instructs the guy with him to call his shop 20 min away and bring up the brand new one for me to try. (these are the gestures that make racing awesome). Within a few minutes the new grid is there. I put it in - head out for my 4 time shots as I race box and no box almost every race I attend. Car is doing the same thing back and forth between 122 and 117 but sometimes running the same MPH twice in a row. But I can hear the change. So I am dialing ~.02 difference (and holding a few) based on the way the motor sounds. Reaction times seem to be staying good 60fts on both sides of the MPH are within a few thousands (also confusing but the way its been). I end up going to the semi finals of box and deep into the rounds in no box - I did have a .048 in no box but that might have been me because I felt I missed it.

Come home disgusted and make a plan to tear the car apart wiring wise from batteries forward with a focus on grounds. I start at the back of the car and as I pull things apart there is a tiny bit of corrosion but nothing notable. Everything is tight. I put star washers under and between every connector and after things are clean and tight - spray it with protective spray which turns to a wax to prevent further corrosion. I work my way forward and have my sensitive stuff on a clean bus and water pumps, starter, etc on a dirty bus. I added another 4 gauge line from the cylinder head to the frame where a 4 gage wire comes to the front. This I know is a waste of time since there is a copper braded ground right below it, but i am adding it anyways. Take off and clean the other grounds, repeating the star washer between every ring connector and spraying. I am looking around and barely can see another ground I ran from battery to front from 3 years ago. These wires feel loose but their connection point is under the car lift pad (put the pads in the same exact spot every time). I lower the car and put it back up with the pads moved. There the ground point and its very loose. I fix the connection and check everything else I could. And remind myself that other thing seemed like the problem and the problem continued.

I head off to bracket finals and first day at T&T the car is faster than all season and is deadly consistent with few thousands - every run at almost 123MPH. Next day is the race of champions I was in. I end up winning that race which was a bucket list item and the car doesn't move more than few thousands. Next race the car is dead on every run and my reaction times in both classes are all <.015. The entire weekend the car works flawless and didn't move more than .01 over 28 runs. I ended up bowing out of both classes in the 5th round with my packages being <.015 but the other guy hitting less than .010 packages.

So take the time to take every ground off your car and make sure they are clean and tight. I still cant believe I missed that ground coming loose and checked a million other things - spent probably 1000+ dollars on other things "it had to be".

Also be sure to verify your voltage drop from your negative battery (under load - fans, lights, everything you can turn on without cranking it) to your various ground points. It should less than .12V, mine after fixing the issue was .012V. And you can also check it cranking the car. Should be under .2V. Mine was .18V.

Hopefully this helps someone. It will be part of my start of the year maintenance. Everything will be cleaned and retighted.

Grounds are important.
My early career being a boat mechanic, (no chassis grounds on a fiberglass vessel) and being in the thick of the automotive repair industry during the advent of computer controls, taught me the value of clean grounds.

Makes a guy wonder if a "floating" ground system is better than a chassis ground set up?

quote:

Originally posted by Al Alguire:
Makes a guy wonder if a "floating" ground system is better than a chassis ground set up?

Guess I would ask what you mean by floating ground.

When I wired my car I have Battery to chassis in back. Battery to chassis front (this is the one that came loose). Battery to isolation lug inside car. Motor to frame. Motor to front battery to chassis ground point. All these battery to have 4 gauge wire.

All my sensitive stuff (racepack, and delay box) is on the isolation lug - which in essence is connected straight to the battery via the 4 gauge wire. Some items also like Grid are connected straight to battery positive and negative.

The isolation lug is not floating like some think since it all goes back to battery (reference). I believe the way I have mine is considered a star ground. Basically everything references the battery negative.