The only thing you need to know about "The Law Of Unintended Consequences" is
- IT'S THE LAW!

REACTION TIME MYSTERY:

I listed four probable causes for my five in a row 6.50 RTs in the last report. The actual cause was number.... Well, it wasn't on the list.

The 6.50 RT mystery is solved. They are an unintended consequence of fixing the front brakes.

Huh? Don't believe me? I don't blame you. It's not intuitive - but I figured it out. The explanation is long winded so I'll leave it for last.


SUSPENSION:

The Moroso Trick Front Springs are in. They are scheduled to be installed Monday, Tuesday and maybe Wednesday too. It's going to be a cut and fit operation - in and out many times - better left to an experienced mechanic with the correct tools. Lee's Bee Line Service will do the work.

I'm very excited about these springs. My suspension just flat out ain't working. If the springs wake it up I'll go back to the "making horsepower" business. The goal is high 6's next year. That will take a cam change. I'm planning to do that over Christmas break.


NEW TIRES:

I was drooling over some 15 wide by 33 tall Hoosiers. I made a section template, to attach to the MTs, to see if they would swing through my tire space. They will not. To fit those tires I'd have to either push the rear end back an inch and hack the inside of the fender, or pull the tubs up an inch. New wheels, with more set back, would be required as well.

Tires are on the back burner anyhow while I evaluate the new front springs. That will take a while. Maybe while enough to wear them out.

SUNDAY'S RACE:

I experimented with foot brake launching and light pressure line lock launching. My longest RT was 5.58.

First round KOH my opponent had a 0.69 RT and ran 3/10ths over his dial. The door was wide open - I stumbled at the threshold. My light was 0.499. Fool on the hill.


THIS WEEK:

Nothing new for Thursday. I'll try a foot brake launch first run. With KOH going into the night I'll need RT margin to avoid red lighting in the later rounds. If there's not enough margin I'll try a soft line lock launch. My chances are not good but still...Winning starts with planning - always plan to win.


THE RT MYSTERY EXPLANATION:

First you need some back ground info.

When I release my line lock there is a time delay before the brake pad's clamping pressure goes low enough to let the car roll. It's always been that way. I can shorten my RTs by locking with less pedal pressure at the line. My custom was to pump the line lock up as hard as I could manage because max pressure is more repeatable than "maybe that's enough" pressure. My slew of KOH wins is a result of that consistency.

So, why the time delay to release the brake pads? I have a restriction in the brake fluid path back to the reservoir - it's the proportioning valve. When I release the line lock you can hear the fluid forcing itself through the restriction in the valve - it goes pshhhhhhhhh. The noise lasts almost a half second as the pressure bleeds down.

I noticed long ago that my front wheels had a bit of drag - and it was uneven from left to right. Not a lot of drag, but fixing that has been on my very long TO DO list for a while. Last week, while I had the wheels of to measure for the springs, I discovered that my calipers were binding in the mounting horns. They were restricted from sliding in and out smoothly as they should. So I got out my BFF (no - not Best Friend Forever) and fixed it. No more restriction. No more caliper drag. No more brake drag.

Now - it makes sense that if they were binding on release they were binding on actuation too. And since all the brake parts are cast iron and mild steel all the parts could bend a little and the brakes worked good. They worked good but it takes a bit more line pressure to achieve a particular clamping force than with unbinding and free moving calipers. Free calipers will require less line pressure to work as well as binding calipers would.

Here's the payoff. Combine all that information.
1.) The brake line pressure reduces slowly over time because of the restriction in the proportioning valve.
2.) At some brake pad clamping pressure the car will roll off the line.
3.) With free moving calipers it takes less line pressure to achieve that clamping force.
4.) It takes more time for the line pressure to come down to the lower line pressure and to the release point, with free moving calipers. Ergo - the car's reaction time is longer.

Sound the horns - TA DA!!!