Many Questions...My Cars Are Slow

Ok I apologize for this beginner newby post but I'm trying to figure out what I'm doing wrong that is causing our car's to be so slow. I'm sure that my axle and wheel polishing is just not as precise as others but I do my best to try to follow the steps in the Black Ice process. I know I also struggle to get the alignment absolutely perfect which most likely adds to the problem. I freely acknowledge that both of these could be causing slower than optimal times but how much I'm not sure. I do have a couple of specific questions though:

1. Am I screwing up by drilling the car prior to trimming and routing?
2. Is there a necessary window after applying Jig when the oil should be applied? I know that it needs at least 15min to gas off before inserting into the wheel bore, but I guess my question is if it is possible to wait too long. If Jig sits on the axle for over an hour before applying oil, does that reduce its effectiveness?
3. Also, after bringing cars home from MA, I looked them over again and noticed a few fairly wobbly wheels. Is slight wobble accepted with an imperfect wheel or is it going to kill a car's time. My guess is that this could have occurred from removing the wheel from the body by pulling on the wheel; probably not a great idea.
4. One other thing I'm not as detailed on is weight balance and squeezing as much out of weight placement as I can. I'm not sure how much this would change things.

I acknowledge that I have a long way to go and am very much an amateur trying to figure out if getting an oil car without fenders down from 1.95 to 1.91 or 1.92 is something bigger than these or is, most likely, a combination of everything.

Again, I really apologize for the newby questions but any guidance is very much appreciated.

 

From what I know, the 4 biggest killers of speed are wheels, alignment, weighting, and body/aerodynamics, in that order.

Wheels:

• Are they scout wheels out of the box or purchased from a reputable vendor?
• Are the wheels at full weight?
• Are the wheels polished (bores, hubs, and ANY surface that touches the track)?
• Are the bores over polished to a point where they are widened or deformed?
• Are the wheels dirty (graphite on the wheels or any foreign substance)?

Alignment

• Did you drill the block with a jig?
• Are you using scout axles or stainless steel 93s?
• Are you bending the rear axles for camber (hope not)?
• Did you over polish your axles making the journals excessively small?

Weighting

• Is the car weighted at 5oz (or as close as you can get)?
• Do you have 2oz behind the rear axle?
• Did you lighten the body (7 to 10 grams) to allow for additional rearward weight placement?

Body/Aerodynamics

• Did you make a "plank" car 1/4" thick or a Fire Truck?
• Did you narrow the front end and bend the front axle to make a rail rider?
• Do you have fenders (either purchased or custom made from balsa)?
• Do you have a 5" wheelbase, with the rear wheels 5/8" from the rear?
• Did you cover all holes, weight pockets, etc., both on the top and bottom?
• Did you use air shields in the wheels?
• Did you use washers (polished AFTER glued to the body)?

Don't worry about the wax, oil, etc. If you are using products from a vendor, you're fine. Focus on the above and 90% of your speed is there. Most importantly, race in a league to gain experience and not once a year at MA. It will help...a lot.

And for what it is worth, wobbly wheels are a bad thing. Just sayin'

 

B_Regal is spot on. Don’t worry about drilling before cutting out, that’s usually how I do it. Racers do it both ways. waiting for Jig isn’t very specific either. Some racers wait 15 minutes, and some wait 16 hours, I don’t think it makes a difference. And yes, the more wobbly, the slower your wheels will be.

 

HANG ON, HANG ON, HANG ON! WHERE HAVE I HEARD THIS BEFORE? SOMEBODY SAYS THIS ALL THE TIME!

 

Thanks a lot, I very much appreciate the lengthy response; I've read a lot on this site and I know there is a lot still out there that I haven't found so I really appreciate you taking the time to respond.

Wheels:
I buy MA wheels from a very reputable vendor; I'm guessing I screwed them up by either over polishing them or mis-shaping them when installing or adjusting gap. They should definitely be clean and have never seen graphite but as far as widening or deforming them, I suppose it's possible but I wouldn't know what to look for to catch if a bore is widened or deformed.

Alignment:
Currently I use the SBE jig and use 93TX pro axles with the FDW bent. I don't think I over polished the axles but I suppose it's always possible. We made four cars and all four were in the 1.95 range so if I did over polish at all, I did it to all of them.

Weighting:
Car was weighted at the max 5oz with 2.13oz behind the rear axle that I usually drill 3/4" from the rear of the car. My bodies aren't quite that light but are more around 11 grams.

Body/Aerodynamics:
I use a blank from a vendor, drill the rears, check for alignment, then drill the front (5" wheel base) with the left front raised. After alignment, I rip the blank down to about 1/4" and then router out the bottom behind the rear axle and then from the front of the rear axle to the back of the front (basically the bulk of the car is routered out to be almost see through. After it's routered, I sand front to a point and narrow slightly by about 1/16" (I probably need to narrow the front more than I do). I haven't currently delved into the world of fenders or air shields for aerodynamics. Maybe it's bad logic but I feel like I want to be able to get a base model right before I add fenders. I install cube weights or the TxW weights trying to get my COG as far back as possible and cover the bottom with aluminum foil tape. Next I clued the washers to the body (but I'll admit, I do not polish them ). Once the car is ready for wheels and axles, I applied Jig and oil to the axles trying to follow the steps you laid out in another post titled 'Transition' (which I might add that you detailed out quite nicely).

I'm sure that my loss of speed is most likely in a combination of a lack of detail in many of these areas. Number one possibly being a wobbly wheel or two and possibly washers not polished. Or, maybe not enough gap and if my alignment isn't perfect, the wheels won't migrate out and will cause drag (especially if washers aren't polished). Also, if my steer isn't tuned in for optimal speed. I agree that one or two races a year is not going to cut it. My next step is to try and get a car good enough to enter in BASX but at this point, it would be woefully behind the pack.




Thanks again a ton, it helps even just to talk through things to find some of my issues.

 

That's good to hear; after getting back from the race, I checked alignment again with the lightning boy method and I could have sworn the alignment was better when I originally drilled it (however it was after drilling many many holes so it might have been wishful thinking or frustration saying it was good ).

 

So is there an avenue to do this in say a BASX class prior to getting stomped in NPWDRL?

 

B_Regal will probably chime in here, but some things I noticed right away were that you weren’t sure about how to measure bore sizes and axle sizes. For bores, I’d recommend getting a set of gage pins. I’d get 5 or 6 from about .095-.098. You shouldn’t be able to fit anything more than a .097 pin in your bores for BASX. The tighter the bore the better. The tightest bore I’ve seen is only about .096 for BASX. For axles, I use calipers. Axles start out at .0925 usually, and they should end either at .0925 or .092. I have found it possible to polish them with keeping them at the original diameter.

A second thing is the weight. Many racers don’t worry about COG. At least to my knowledge. Personally, I make sure I have about .2 oz more on the non dominant side back wheel. On the front wheel, I’ll have anywhere from 10 to 15 grams. Weight will often depend on the car, it’s best to tune that after each race until it gets to its peak.

Also, with narrowing your car, there’s not necessarily a fixed dimension. If you roll your car down a track, or a piece of track, make sure the rear wheels don’t hit the rails. If they are, you need to either sand the dominant side more or you sanded it too much. Usually it’s that not sanded enough. That could be a major speed loss if your car is hitting the rails in the rear. I’d recommend getting just a piece of track if you don’t have a full track.

Last thing you touched on, the washers, your going to want to polish those for sure! After glueing, they can be pretty rough, and it would probably be better to run no washer at that point. They don’t usually take long to polish, and when done right, they are really smooth.

Hope that helps!

 

Yes! Both NPWDRL and APR have BASX AM classes! Many of us started out there to get our feet wet!

 

Just send it!! You'll learn as you go.

 

Thanks; this is very helpful. I have a full set pin gauges and checked the bores this morning right after I read your post; most of the wheels are .097 but there were a few at .098 so thats not good.
Ordered some calipers this morning and will definitely make that part of my process to check axle diameter.

Thanks, again!!!

 

I have not raced in 2 years for one reason or another. I do, however, keep collecting new parts and perform test after test. I have a good 10 to 12 cars in pieces for more reasons that don't make sense. T-Bone was nudging me in the right direction.

But,

It sounds like you have the basics down. I typically run tight gaps but every now and then I make a car where the gaps do not appear to be related to speed, but that's not usual for me. I know because I could be lost in the basement for hours playing with a silly wooden car on my track. Maybe though, it is the attention to detail. The best racers are ultra meticulous, and that's the big secret. There're are no other secrets. Wobbly wheels - could be over polished axles (some one around here recently had that problem) or over polished bores. That can also cause the wiggles.

Bad alignment = speed killer. I always check the car alignment after drilling and several times during the build process. If I ever question the alignment, the car is fire wood.

Looks like you ran Adult Oil. I do not see the video or the results. Sometimes there are things you can learn from watching your car in a race...

 

Thanks for everything; I truly appreciate your time.

 

Lots of good advice shared in this thread, but I think maybe that’s the best piece of advice I’ve seen. I’ll definitely remember and apply that.

 

This may have been mentioned but based on your MA time and the photo your time is really very very good considering the aerodynamic extras left to take advantage of.

Still if you had a wiggle that is the place to look first. Also running slightly behind a pack of top flight cars may cause some “dirty air” exaggerating any imbalance.

The times that made the finals were elite for this class. My most satisfying run at MA was with a 2.95 car a few years back. You did very well.

I’ll miss MA and always loved that rule package. It’s a great balance of innovation, skill, enforcibility and an attempt to stay with the pinewood basics. We adapted those specs locally. I really applaud Greg and crew for coming up with them.

 

Thanks, appreciate the encouragement. Got a long way to go but am enjoying the challenge for sure.

Are you implying that MA is no more?

 

That is my understanding based on Facebook post and Greg’s sign off on the video link. I wasn’t there in person and have not asked him. Hopefully I misunderstood.