21 replies to this topic

[gonegonzo]

I have sveral drag cars . most have super 16D motors . I have enough speed and heads up I do OK but I need consistent ET's . I prep the cars the same each run but never consistent .

 

Any suggestions ?

 

Thx Gonzo

[chasbeeman]

Track conditions play a big part, I've seen some wipe down the entire lane to control how much glue is there. Even if glue is not allowed on track itself there is residue left after every pass.

[gonegonzo]

All of my cars seem to need a trifle amount of glue to keep from spinning all the way down the track . I forgot to mention we ar running a 1/24th scale 1/8th mile .

 Thx for your reply .

 

Gonzo

[gotboostedvr6]

Your rubber might be bad.
Bad meaning crap rubber or dry rot.

[Brian Czeiner]

You didn't mention if your cars had wheelie bars. Try raising them. Put a business card under and resolder them. This will put more tire on the track surface. If you take the glue out of the equation, it becomes one less variable resulting in more consistent ETs. 

[gonegonzo]

My tires are in good shape , no rot , flat spots or defects . One thing I haven't tried is a completely clean track . I did need 

glue to hook up but maybe the tires have enough glue soaked in a clean pass would be ok to try . 3 of the cars have new rear tires with 2 weeks of racing on them .

 

This is my first year back racing after a 2 year hiatus . it's amazing what you forget .

 

Gonzo

[mreibman]

It is possible it's the track power. Have you measured track voltage with a decent meter?
If it fluctuates, so will your time.

You could add a capacitor across it out lead wires as a filter like back in the day. You could also opt for a voltage regulator (transistor) to lock yourself in at a set voltage all the time, i.e. 14v instead of whatever the track is putting out.

Talk to the track owner regarding power - probably a safe place to start.

[gonegonzo]

Hi mreibman . I know that he changed to a new power supply bout 4 years ago . nobody else seems plagued with this . Actually , I used a buddies dragster last Saturday and it was consistent . I'm sure the owner will check voltage for me however .

 

I failed to mention above that my wheelie bars are set with a business card .

 

Where is Merrick N Y ? Is that on Long Island ?

 

Thx ,

Gonzo

[Dave Crevie]

What manufacture are the 16Ds? The Parmas have been spotty lately. If you are getting consistant times with another car, I will take 

response time out of the equation. I will tell you that when I had my dragstrip, we had debated using glue. Some said they needed it, 

some didn't want the mess. After a few meets trying each, it became obvious that no-glue was the way to go. I made "bleach boxes"

before the start lines of each lane from some 320 Wet-or-Dry sandpaper double-stickeyed to the track surface. Each contender could

do a "burn out" on the sandpaper using lighter fluid on the tires to warm up the rubber. Not only made faster times, but added a little

"realism" to each run.   

[Tim Neja]

The biggest problem with "glue" racing is all the TIME IT TAKES prepping the lanes!! I LOVE the idea of your "burn out" per above and NO GLUE prepping!! BPR found that they got 3 times as many races in and more racers with NO glue prepping.  They have NO GLUE racing days now!! Much more fun to be RACING than waiting in line for the "preppars" to wipe down and glue their lanes!!  Most likely I'd try a different motor in your car. I've experienced consistancy problems with different motors. Brush's etc. can create lot's of variables.

[gonegonzo]

Dave , I do have Parma 16D's in the cars . However , unless I recieved a batch of bad ones , others are having good luck with them . 

 

I will take your advise and  swap a couple out to eliminate that eliment . If it works out , I'll have a motor sale .

 

Thx,

Gonzo

[Dan Ebert]

When cars go from good to bad.  3 things I check. 1.  Burnt or dirty braid,  some shutdown areas are so loaded with glue.  It will cover your contact braid. When racing I clean my braid after every pass.   2nd Tires you may think they are good and feel tacky.  But after awhile they get a glue buildup and get dried out.  3rd  Check Motor brush wear.     Good Luck

[Brian Czeiner]

Had another thought.....Have you trued the tires? Just because they are new doesn't mean they are round.

[gonegonzo]

Dan and Brian , Cleaning my braids is part of my prep between runs . I do clean my tires with lighter fluid but have never checked beyond them being new if they were round or not . I just took for granted new tires were trued .

 

No I haven't checked my brushes . My bad there for sure as it's an obvious culprit . I have new brushes sitting here .

 

OK , i'm bust again with brush swapping and checking my tires for true .

 

Thx 

Gonzo

[Dan Ebert]

Just had a car go south on me.  It was a steady performer.  Sure enough Motor Brushes were short.  I made the change and I will test it tomorrow to see if it is back to normal.     Another last shot in the dark, is to check all solder joints.  Sometimes a cracked solder joint will not show with visual inspection.  If you have a break somewhere.  You could be twisting the chassis under load causing inconsistent grip or loss of torque.

[Tom Katsanis]

If you work out how to make your times consistent let me know I find the track conditions & temp can effect times.

Another thing you can look at is weight maybe the track gets a little sticky as the night progresses & the front is pulling up just enough to not get a great contact on the braid slowing your cars.

[gonegonzo]

Thx Dan and Tom . both points well taken . 

 

dan , I never thought of it being a chassis thing , only a mechenical or electric issue .

 

Actually Tom , I don't run weight in any of my cars . Maybe that's the place to look .

 

Thx , Gonzo

[Dominator]

Another way to adjust your wheelie bars is adding or removing a guide spacer. I know guide spacers are not needed with drags but if you set up with spacers initially it will help tuning on the fly.

[Dan Ebert]

I carry O-rings of several different sizes.  I can fine tune my wheelie bar height with a simple change with the O-rings.   Much easier than pulling the body off and removing or adding guide spacers. 

[Charley]

I would look at gear ratio.. I run a larger pinion to leave soft and the motor will catch up with itself down the track. In other words, no glue and a soft launch.

But like Brian said, out of round tires will give crazy times also.

If you are running "bracket racing", look at using a voltage regulator on the motor. Not a resistor. The voltage regulator will keep the output voltage the same no matter how much voltage you feed it.

 

Just my thoughts.

 

Charley

[Dave Crevie]

The gear ration is a constant. If it is wrong, the car will be consistently slow. You have to check the variables. Bad braid, bad brushes, tires not

prepped the same each run, and of course condition of the track (glue). 

[Charley]

Yes, the gear ratio is a constant. If the gear ratio allows the car to leave softer, the rest of the variables are more forgiving. This is a fact that I have learned from racing drag slot cars since the '60's, and I have been as fast as 124mph at .420et to a blistering 18mph with a 2.894 et. I have cars now that will run their times within .004 every pull of the trigger at my track. 

I do agree that "track preparation" MUST be the same every time.

 

just my thoughts.