RE: OS .12 LD Power Block
A little known fact about the .12 LD (lay down) is that it does not use the standard .12-.15 od sleeve. If you want to make an absolute screamer out of it, order a Tamiya FS.18 SR piston and sleeve. The SR has a smaller inner and outer diameter sleeve than the standard Tamiya 15 and 18 LT series motors, and it fits perfectly into the OS 12 LD bore. The only thing you need to do is dremel out the inner bore to feed the much larger ports. If you find one of these NIB, I would probably not mess with it, but if you find a few cheap like I did on ebay, then you can afford to play with them. It is great to get a high revving, powerful engine out of this lay down package. Tower still carries some parts for this engine, but the cranks are model specific to this engine, because the timing is off 90 degrees to compensate for the carb being 90 degrees off from the cylinder, which is now laid down. I am currently custom building one now that I will start a new thread on it when it is done. I have re-machined the case to accept a larger carb, and reported it to take the .18SR piston and sleeve. It is going in a heavily modified TG10R converted to front drive only, for an 8th scale Tamiya Mini. The engine sits over the front diff, and just fits under the hood of the car. The other 18 resleeved LD would have run great in it, but the carb is the limiting factor with it. The new one should really scream. Stay tuned, and they are nice if you just want to run them stock too.
Posted on: 4/16/2009 2:05 AM by Author "tonykalil" in the forum "Car Nitro & Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=8686089

RE: Higher car for better side grip?
Ziggy, you are right on. However, sometimes, you do not have the luxury of a low CG, so you just adjust your roll center up to accomodate it. So long as you are not keeping the roll center too far under the CG, you will have a vehicle that perfoms well. Spetz, if I understand your question correctly, I assume you are asking why you would alter the stiffness of the sway bar on the front or rear. By adjusting the stiffness of one end of the car, you actually affect the opposite end. If you want the car to turn in sharply, you stiffen up the rear sway bar. This is because when the car goes into the corner, the front will set into the corner with (as equal a weight as you can get) on both tires (assuming no sway bar). However, the rear inner tire is lifted, because it is essentially linked to the outer rear tire, so you are "picking up" the inner rear, and causing the rear to have less grip. This is just an extreme, as no real race car would run just a front or rear - you balance the stiffness of both sway bars to control the balance of the car. Many race cars actually have adjustable rear sway bars to allow better turn in during the race. The reason you are getting better grip with a softer setup is because all of the tires are now allowed more contact with the road. If the suspension is too hard, the wheels will skip, or bounce over the texture of the road, and you will have minimal grip. It is almost like running an F1 car over a track of closely spaced speed bumps. The car would rarely touch the ground, however, a regular street car with compliant suspension would allow the tires to soak up the bumps, and keep them placed on the pavement much better. If you run soft springs, stiff shocks, and stiff sway bars, you will have the best basher setup that you can imagine. Make sure the suspension has alot of jounce, and rebound, meaning that the car settles half way down on the springs when you set it on the ground. This has been the principal behind every Lotus suspension. Colin Chapman was a brilliant engineer, and he came up with this formula. The cars were stiffly shocked and had massive sway bars, but they always had soft springs. This also allowed the cars to take less punishment since most of the bumps in the road were converted to heat through the shocks (yep, that is what they actually do) instead of transmitting the forces into the chassis. I hope this helps
Posted on: 10/25/2008 9:20 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8084651

RE: Higher car for better side grip?
Hey Trini, I think you get what he is gettin at, it is just a flawed theory. The amount of grip that 2 tires can generate is less than the amount that 4 can generate. Because rolling to the outside would lessen the grip on the inside tires, the net effect (or total amount of gripping force) is less than a level car would generate. Spetz, body roll does not generate grip under any circumstance. What it does, is preload the tire sidewall, so that the slack is taken up and the tire can impart the greatest force to the car. On my Porsche (real car), the tires can only go in one spot on the car. That means that you can not rotate them. The right front must always go on the right front, and the left rear...etc. The tires are designed to "roll in". This means that if you roll the right tires down the street by themselves, they will naturally follow a left curve. This is to pre-load the tires so that the sidewall is always loaded, and a steering input can quickly be converted into a turn. It is obviously less practical to do this on most street cars, so they go with symetrical tires, and generate body roll. But race cars want zero roll. Transferring weight means that you have to transfer it back again, and engineers want the CAR to change direction, not its WEIGHT. The main difference in RC cars and scale cars is the toe in of the front end. RC cars almost always have the front wheels toed out. This is only for one reason, and that is to make it go as straight as possible. The effect of preloading the tires goes out the window here, since the tires are preloaded the WRONG WAY. They do this because almost every RC car steering geometry is incorrect. When you push the wheel up, most tires turn in a little more due to the tie rod being at a different angle to the roll center. This causes the cars to oversteer in corners - when the car enters the corner, it compresses the suspension, which turns the wheel more than you intended. This causes a chain reaction that loads the suspension even more and turns the wheels even more. If you want to run with toe in - like a real car, flip the ball end to the other side of the spindle so that when you compress the suspension, the wheel does not oversteer. This will give you a crisp handling car that still tracks straight. Like I always say, it is all in the setup.
Posted on: 10/23/2008 8:36 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8078880

RE: Higher car for better side grip?
[quote]ORIGINAL: Spetz I realise that taller + softer might mean you can't change direction quickly, it gets out of balance easily etc etc But for sheer side grip, is taller better? I am running my car at standard height... and considering lowering it by about 5mm or so [/quote] For sheer grip, keep your car as low as possible, with the exception of clearance for the condition of your street. You might remember me saying that I run some of my cars high and soft, but it is definately not for grip. For grip, you need all four tires placed as firmly as you can get them. Raising the ride height makes the car transfer weight off of the inside tires, and you can never regain that lost grip even with the added grip of the outside tires. By the way, I think the F1 bus comparison is referring to the rule passes a few years ago that mandated a "plank" on the bottom of the car to interrupt a flat and low sidepod. It was an idea to slow the cars down. It unfortunately raises the ride height of the cars, however, on the other hand, he may be referring to the fact that Double Decker busses are very low to the ground?? Your guess. Trini, cars are lower in the front mostly for stance. The "performance stance" of a lower front ride height comes from drag racing cars that needed to transfer weight to the rear tires. In the late 50s and early 60s, drag cars were actually totally raised about 1 foot (see altered drag cars) to transfer the most amount of weight to the rear tires when accelerating. All real race cars have at most 1/2 degree of drop in the nose. This is to allow the bottom of the car to act as a diffuser, which increases downforce. With street cars, the disturbed bottom can't use any air to ant benefit, but lowering the nose sure looks cool! The balance of the car has a little to do with ride height, and much more to do with roll centers. Roll centers are the theoretical axis upon which the car roll, or transfers weight. It is determined by the angle of the suspension arms. A live axle has its roll center dead center. A high Center of Gravity can be made competetive if the roll centers coincide with the high CG. That is how those race trucks in Europe corner so well. But lowering a car too much will cause the suspension arms to force the roll center below the surface of the road, and the car will not corner at all! This is a huge problem with 5.0 Mustangs. Kids lower them, and then they expect them to handle great - but instead, they plow, or push through corners. This is why smart kids get drop spindles, which lower the ride height, but leave the suspension geometry alone. The same translates to our RC cars. Making sure the angles of the upper suspension arms is correct is a very important factor when setting up your RC car.
Posted on: 10/22/2008 11:17 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8075951

RE: Overgearing an engine, safe?
Hey Spetz, I have read alot of good ideas in this topic. Try wide tires, and if your radio has an exponential setting on the throttle, use it. Make it so that the bottom end is very precise, and it will cure alot of the trouble. If you want to make it foolproof, put the ball diff in the rear, but don't run it too loose. The TZ will torch it fast. I run a TZ in two of my TGXs like yours right now, and they are great as bashers. Bigger gears will definately help, but don't restrict the carb. The whole reason for having the TZ in your car is to make sure your only problem is TOO MUCH POWER. I can live with problems like that! If you want to help the longevity of the motor and make it a little more drivable, just richen it up a little - you know I swear by it. Now, Rip the Cord, Squeeze the Trigger, and Abuse those Tires! Anthony
Posted on: 10/22/2008 12:06 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8072553

RE: Higher car for better side grip?
Hey Spetz, It sounds like a good theory, but in reality, the grip you gain on the outside tire is lost to the grip you lose on the inner tires. As you force more weight down on the outer tires, some energy is lost to heat that can never be regained. It is very small, but still measureable. It is this reason that all race cars (track cars) try to keep the car as level as possible. Also, as you corner, you want the weight distributed in a balanced manner so that you can set a car up in the corner. If you apply power or brakes, you always run the risk of upsetting the car which is going the maximum possible speed through a corner. For this to happen, the car must be at its maximum level of adhesion, and for this, all of the tires must be working to their best ability. I hope this helps, Anthony
Posted on: 10/21/2008 11:58 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8072538

RE: rs4 drift...dead
Like any kind of driving, you don't go at it with the throttle mashed wide open full time. That will destroy any engine. I am talking about the relative amount of fuel and lubrication going through an engine for a given RPM. You will of course blow up an engine if you run it on a bench wide open, but you will also blow it up even if you give it 10% throttle with no load.
Posted on: 10/10/2008 3:44 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8036774

RE: Front one way diff
I still find tons of out-of-production parts on Etamiya. Sometimes you have to look in the incorrect categories, but they are hiding in there.
Posted on: 10/9/2008 1:23 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8032382

RE: Clearance distance between tyre?
The RACY will fix all of that. Once it hits second, it locks in and goes.
Posted on: 10/9/2008 1:19 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8032372

RE: Tamiya TG-R
Most of the cars run the front body mounts. Only the sedans and boxy cars use the high mounts. The TGRs only have the low front mounts, but they give you a choice of low and lower rear mounts. The Nissan R390 and the TS 020 use the extra low rear mounts.
Posted on: 10/9/2008 1:17 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8032364

RE: rs4 drift...dead
I have found that drifting eats nitro motors almost more than running them wide open on a track. First, you have minimal cooling since the car is not going that fast, and second, the motor turns relatively high RPMs in relation to throttle input because the wheels are always spinning. This means that you have less fuel and lubrication running through the motor per RPM since the loading condition is considerably less. It is almost like running the motor with the wheels off of the ground. My motors blew a rod just like yours. After eating two motors back to back in my drifting car, I decided to run it richer, and I used one of the Tamiya FS15s with the integral cooling fan. It runs like a top, and I have never had a problem with the motor since. I hope this helps.
Posted on: 10/9/2008 1:13 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8032354

RE: Tamiya TG-R
I run the HPI Corvette body on my Banzai basher. It actually looks nice for an HPI body, and it is far cheaper than the Tamiya bodies. The HPIs are not as scale, but when putting them into a curb at 70, or under a tire, they look jusy fine. The holes are in the right spot, but you need to run the front body mounts on your car. I think all of the HPIs run GT body mounts. If you have the Subaru, you are set up for the sedan, or high body mounts. If you want to run any of the fast bodies - Vette, Supra, Viper, Lambo, etc, you need to take the rear long posts off and put them on the front bumper. Take the short front ones off of the front shock tower mount and put them on the rear. The TGX was designed like this to give you the option of running sedan bodies or GT bodies.
Posted on: 10/2/2008 2:12 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8011141

RE: Too rich/too lean?
Hey Spetz, Isn't that TZ brand new? Did you finish breaking it in before leaning it? It sounds lean on top. Don't be afraid to run it rich for a few tanks, it will pay off in the long run. I break my engines in at WOT running full rich for about 15 tanks, then slowly step the needle back for another 25 tanks. At full rich, the tanks go in a few minutes, so don't think of this method as a pain, it is actually more fun, because you can at least run the thing around some. This method works very well, because you are passing massive amounts of fuel and lubrication through the engine. If you want to try this next time, just fire the thing off, and then wind the needle all the way out while giving it some throttle. You should end up at WOT, and the needle valve just screwed in enough to keep it from falling out. You can now drive the car around at jogging speed, and it will stay cool and lubricated. Check your head temp, as some engines will not even register a temperature due to the effective cooling of this break in method. If it is too cold, you can score the liner. On some standard 3 port Tamiya motors, you can run the engine like this and hold the car by the head! The TZ supplies enough air through the multi-ports to actually run with the needle valve [i]removed[/i]. It won't run as cold as some other motors, because it has a great capacity to burn lots of fuel. If it stalls, fire it off with the throttle mashed. It will re-fire. As you keep winding the needle in, you will find a good tune, and when you get the performance you want, you can stop leaning it. Trust me on this, the TZ has more than enough power to make your TGX scream, so go for longeveity rather than balls out performance. Just my 02c Anthony
Posted on: 10/2/2008 2:00 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8011123

RE: Clearance distance between tyre?
I honestly don't know how fast it is compared to today's 8th scale cars, but it definately was quick. If you search Youtube for TGR, you will see some on the track. They are impressive. The slip you get is from the 2nd gear clutch. When it is worn, the car will accelerate in 1st, then go for second, but the clutch does not hold. The motor then over-revs severely, until the car slows down enough for 1st gear to catch again. The Racy 2 speed cam-type clutch will solve this for good. Did you ever put yours in? If you are sweating the 1 way diff, just buy a second plastic diff carrier off of ebay (like $7-$15) and assemble a whole new front end. The you can swap them out with the four screws on the bottom, and the two on top. You can have two different setups with only about 10 minutes work. That way if you want to run a long track you can swap it out. Anthony
Posted on: 9/28/2008 10:25 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=8000342

RE: Clearance distance between tyre?
The TGR on its stock tires is amazing. If you get one of the kits off of ebay, they will have the slicks wrapped in plastic so they will be sticky. I built mine out of the box, and when you lifted the car off of the table, the tires would actually stick it down! Like I said, if you are used to driving your TGX, you will be mind blown when you see the difference between the two. My buddy built the Subaru WRC1999 car with the rally tires, and his car behaved just like yours. When I took the 1 way out of my long track car, I gave it to him. With his rally tires still on it, it performs better than a slick tired TGX without the 1 way. He loves it now. The IGT2 probably is a better buy for you. You are correct about parts, but if you look on ebay, you can still get every TGR part, they are just not at your local hobby shop. As far as performance, I honestly do not know, as I have never run an IGT2. I hear they are great, but I am an old Tamiya guy. I also can't imagine wanting anything better than the TGR. I need to take some vids of it running for you, as well as the TGX 1 way setup. You'll run out and buy one when you see it run.
Posted on: 9/23/2008 11:51 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7976057

RE: Tamiya TG-R
The pipe on the R390 goes about 3/4" past the front wheel. I tuck it tight inside, and there is about 1/4" distance to the tire when it is fully turned. You don't need much clearance. Just enough is perfect.
Posted on: 9/23/2008 8:20 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7984407

RE: Clearance distance between tyre?
[quote]ORIGINAL: Spetz I think with engines like the 18TZ you can run them rich as they have power to spare. It's the weaker engines where you end up running them leaner to get some more go from them I've thought about the 1 way diff, but having no front brakes is a huge problem though especially in bashing as I do a lot of top speed runs. I will probably buy one though sooner or later as they're only $15 or so With the carbon decks I meant that I saw a TGX (pics) with a carbon lower deck as well as carbon upper deck I wonder if a fully hopped up TGX would be "better" than a standard TGR? Carbon everything, alloy where it needs it, TRF dampers, 1 way etc [/quote] Don't get me wrong. Running any engine rich will take some power away. I am talking about running enough heat to burn the excess fuel in any motor. The TZ and other 5 and 7 port engines do this better because they can atomize more fuel inside the cylinder without drowning it, but this works to a lesser degree in my standard 3 port Tamiya LT motors. Try the 1 way. You will be amazed at how little you need brakes when you learn to carry momentum through corners. I have never seen a lower Carbon Deck. Honestly, I do not know if it was a homemade piece, because you need to have the lower deck made out of aluminum in order to carry heat away from the engine. Carbon does not transmit heat very well, and it would essentially remove the largest heatsink in the car. I have several TGXs with every available Tamiya option. They also have some extra hop ups from aftermarket companies. The TGX will never come close to a TGR in any respect, because it is designed differently. It has a higher CG, much more polar inertia(weight out to the sides), and carrys much more weight in general. It is like expecting the best stock car in the world to keep up with a Formula 1 car. It is just in a completely different class. The TGR has no need for 1 way and ball diffs. It already has all of the carbon it needs, and it has unmatched suspension geometry. Oddly enough, I think a TGX is way more fun to drive just for this reason. It slides through corners, and you get to drive it. The TGR is on rails, and it just goes where you want it to with no fuss. If you ever get the chance to pick one up, don't hesitate. They were the best cars that never sold.
Posted on: 9/21/2008 2:10 PM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7975970

RE: Clearance distance between tyre?
Spetz, Nitrohead is correct, the longer the tube, the more back pressure you get. That is why I flip the pipe over on my faster cars- the tube ends up being shorter. But if you are just bashing, there are a couple of things you can do to minimize this loss. The TGX I sent a pic of has an extremely large diameter tube, so the pressure is minimal. But you can make the back pressure work for you with the correct pipe and tune. Get this: I run an extremely large pressure and fuel line to overfuel the motor. The back pressure from the exaust tube over pressurizes the tank at wide open throttle, which makes the car run super rich. I keep the body holes to a minimum, so the car holds alot of heat. The extra heat helps burn most of the fuel. This only works with the correct pipe setup, as it has to do with the timing of the exhaust port of the engine, and it works best in multi port engines. A standard 3 port will usually drown out, but the 5 and 7 port engines like the TZ can use/burn gobs of fuel. This combo allows me to run the Banzai setup, which is my endurance speed car. When you are following it in the truck, it just starts building heat and rpms. It is amazing to see it get on the pipe and go, and it allows the car to stay at top speed for 2 minutes (thats all the tank lasts) without burning plugs. The minimal holes in the body greatly help the aerodynamics, and the same body without the windshield cutout is good for 5mph extra. When the throttle is less than wide open, the pressure gets out of the exhaust tube, and it runs normally. The downsides are terrible fuel consumption at WOT and it is boggy when it is cold. Once you build heat, the TZ will burn the fuel. The motor will also last forever. Like I mentioned in an earlier post, I have motors I have been running like this for 20 years on the same piston, sleeve, (and plug on one motor!) But like nitrohead said, it still costs you on the very top, especially if the tube is smaller in diameter. If you are competitively racing, you would never have the tube, but for bashing, the car stays clean. PM me if you want part numbers to set it up like mine. Anthony
Posted on: 9/21/2008 1:31 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7973812

RE: Clearance distance between tyre?
The TGX pictured has the Carbon Upper Deck. It cuts weight a little, but it helps with the steering precision. The top deck kit comes with machined aluminum servo mounts that hold the steering servo in with zero slop. When you put a drop of CA in the ball joints, it makes a very tight linkage with no slop (RC Jet trick) You will never notice this on a basher, but in a high speed car that you are following at 75mph, it is a must. The thing tracks straight as an arrow. The single largest difference you will ever notice is the front 1 way diff. It will make it a super sharp tight track car out of a car that otherwise pushes. If you have bad tires, this is even more of a must, since you will not be relying on poor tire grip to turn the car. Instead, you will be tossing the weight of the car, and watching it drift through corners. Pick one up, they are not too expensive. Thanks CarBoy. The setup works pretty well for what I need on this car. The car can bash on the street just fine, but it can also sustain full load and top speed for the entire tank of fuel. Most of my cars are setup to run richer than normal. They last forever, idle like 4 strokes, and run fairly cool. None of them have burned fuel all over them. Anthony
Posted on: 9/21/2008 1:23 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7974771

RE: Clearance distance between tyre?
Hey Spetz, I had that same pipe on my 18TZ TGX. You should be fine. On my car, I got more clearance when I used the TG10r clutch bell, because it is shorter so I redrilled the engine mounts and moved the motor back. But before the clutch/gear swap, I had to shorten the pipe mount so that it went just inside the tire. Now, I flipped it over the back, so none of it matters anyway, but it did fit tight, but fine. Keep the pipe as close to the chassis as possible, and it will fit better. Don't worry about binding the coupler a tiny bit. Keeping the pipe closer to the chassis will protect the header better if you are just bashing. Here is my current pipe setup on the TZ TGX. I will see if I have pics of the old setup that you are talking about so you can see. On one of my TGRs, the pipe goes past the front wheel, so it is tucked way in. I wanted the long pipe to build more torque for big gears
Posted on: 9/20/2008 1:06 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7972034

RE: Going For 70+MPH OR DIE TRYING..........
Look on his Youtube page. It ran 71
Posted on: 9/17/2008 9:30 PM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7965008

RE: Going For 70+MPH OR DIE TRYING..........
[quote] I'm pretty comfortable with trig and I get the same % errors you do, but the 6 MPH error you mentioned in a previous post wouldn't be caused by Cosine error unless your car was going insanely fast or your gun angle was a lot more than 10 degrees. [/quote] Look at that video and the guy holding the radar gun again. I think I am being conservative at 12-15 degrees. He pointing it to the side [i]and[/i] down. We are kind of going back and forth over symantics, but here are the basics: The Baja was going faster than the radar speed indicated. The whole reason to radar your car is to prove how fast it is. If you aim correctly, you can pick up more of your actual speed. Depending on the angle, you can loose 2-6 mph, or more with greater angles. A casual eye will confirm that the radar angle was at minimum 10' vertical, with probably another 8' horizontally which I have not accounted for, which puts the Baja at 75mph 75 MPH is better than 71 MPH (unless you get busted speeding) Best regards, and here's to going for 75mph or die trying
Posted on: 9/17/2008 5:24 PM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7964205

RE: Going For 70+MPH OR DIE TRYING..........
Hello SD2006, Your math is just a little off. Looking at the video again, it looks like the gun is about 12-15 degrees to the side. He is getting the top speed reading when the car is less than 20 feet in front of him. At 15 degrees, you are only getting about 95% of your total speed. So dividing 71 by .95 gives you 74.73, or 75mph. At 12 degree, you are about 97% accurate, but that still gives you 73.19. Here is some info from Stalker [i]Q - What is Cosine Error? A - The most common mistake made with all radars is trying to clock targets at angles. All radars should clock objects moving directly at or away from the radar. Clocking at an angle with a stationary radar will result in angle error, and the radar will display a speed that is LOWER than the actual speed. In order to get accurate readings, the radar must be placed in the line of travel of the target. At slight angles, the error will be very small, however at larger angles, the error will be substantial. If you know the angle, you can calculate the actual speed by taking the radar reading and dividing by the cosine of the angle. For example: if your angle is 30 degrees and the radar reads 129.9 mph. Take 129.9 and divide by the cosine of 30 degrees (0.866) to get a true speed of 150.0 mph.[/i] They also train the cops to bust you for maximum speed. Here is a page from their training: [i]Cosine Error Geometry Microwave and Laser Radars Chapter 4.1 Setup Overpass Hills / Curves Cosine Error Traffic radars measure the relative speed a target is approaching (or receding) the radar. If a target is traveling directly (collision course) at the radar, the relative speed is actual target speed. If the target is not traveling directly toward (or away) the radar but slightly off to avoid a collision, the relative speed with respect to the radar is slightly lower than target speed. The phenomenon is called the Cosine Effect because the measured speed is directly related to the cosine of the angle (alpha) between the radar and target direction of travel (see figure below). Setput Figure 4.1-1 Cosine Effect Setup The cosine effect angle (alpha) is the angle between the radar and the target direction of travel. Target range from radar and radar distance off the road (really the distance between radar and the point the target would be closest to radar if target continues in same direction) determine the cosine effect angle. Note that the road direction and antenna direction (direction antenna pointed) are completely irrelevant, only the angle (alpha) matters (radar stationary). Antenna direction (alignment to patrol car direction) is important in moving mode radar. A mis-aligned antenna measures target speed high if the misalignment is great enough, the target is approaching the moving radar, and the target is traveling slower than the radar (chapter 4.3 Cosine Effect on Moving Radar). As long as the angle (alpha) remains relatively small, the error (cosine of alpha) is tolerable. The larger the angle, the larger the error and the lower the displayed (relative) speed. On a straight section of road, radar distance from the road and the range of the target determine the angle. The greater the distance the radar is off the road and/or the closer the target, the larger the angle (and error). When the target is even with the radar (alpha equals 90 degrees) the target speed, with respect (relative) to the radar, is zero. The Cosine Effect applies to both microwave radars and laser radars (ladars) as well as to targets traveling in any direction (on-coming or going traffic at any angle). Most traffic radars do not account for the Cosine Effect; across the road microwave radars (such as photo radars) are an exception. These systems point the beam at a known fixed angle across the road and compensate the measured target speed for the Cosine Effect. Overpass Figure 4.1-2 Cosine Effect from an Overpass The radar distance from (off) the road is the line-of-sight distance from the radar to the road (target path). If the radar is on an overpass (shooting cars running under the overpass) or hill for example, the radar distance from the road is the distance from the radar position to the road (target path) as in the side figure. In the figure the traffic is traveling directly away or into the page. In the side figure, x represents the horizontal distance and y represents the vertical distance from the road to the radar. The line-of-sight distance is d. If either the horizontal or vertical component is zero, the equations reduce to that shown in figure 4.1-1 where d = y (if x = 0), or d = x (if y = 0). When applying the equations, all distances must use the same unit dimensions (feet, meters, etc.). When calculating the angle (alpha) using the inverse tangent function (arctan), the unit dimension of the calculated angle is radians (rad), not degrees. Pi (3.14159...) radians equals 180 degrees; one radian approximately equals 57.3 degrees. Degrees = radians x (180/pi). Hills or Curves On hills or curves target direction (with respect to radar) is changing, this causes the Cosine Effect angle (alpha) to change. A changing Cosine Effect angle results in measured target speed changing, the faster the angle changes the faster measured target speed changes (acceleration or deceleration component). If measured speed changes too fast the radar misses (does not display) target speed. Figure 4.1-3 Cosine Effect Due to Hills / Curves Note the above figures illustrates targets on a hill (side view), or a curved road (top view). Alpha is the Cosine Effect angle, d is radar (closest) distance from target path. The steeper the hill or the tighter the curve the greater the angle alpha, and the greater the measured speed error and the greater the acceleration component. Moving radar introduces another component that generally increases the target acceleration component for approaching or receding targets, and decreases for same-lane targets. Also see; chapter 4.5 Targets on a Curve chapter 5.4 Operational problems / Target Acceleration Cosine Error The below figure is a graphical representation of the Cosine Effect for measured speed, as a percentage of true speed versus angle (alpha) between radar and target the larger the angle the larger the error and the lower the measured target speed. For example at angles of only a few degrees the measured speed is 99 to 100 percent of actual; at an angle of 60 degrees the measured speed is half (50 percent) the actual target speed. Figure 4.1-4 Angle vs Measured Speed (percent of actual speed)[/i] Its a boring read, but it gives you the basics. If you are going for TOP SPEED, get in front of it. When I radar with my buddy, we get our reading by standing in front of it with the gun handle touching the ground. If you are getting a perfectly straight shot from 100 feet away, you have plenty of time to get out of the way. Miami, your Baja did 75.
Posted on: 9/17/2008 4:09 AM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7962538

RE: Front one way diff
??? Are you guys talking about a 1 way diff, or a ball diff? My 1 way diffs are just a ring gear with two one way bearings like you find in the pull starter. There is no grinding, noise, or wear-in of the diff. It is just a set of forward freewheeling bearings. They are silky smooth, and silent. Maybe the Tamiyas are different. Anthony
Posted on: 9/17/2008 3:13 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7962488

RE: Going For 70+MPH OR DIE TRYING..........
I was thinking more like a ramp!
Posted on: 9/16/2008 5:47 PM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7960774

RE: Going For 70+MPH OR DIE TRYING..........
Hey Miami, the next time you have two guns at the same time like in the vid, try angling ONE of them. You will see the difference, I promise. The only way I found this was holding two guns at the same time in one hand, and a camera in the other. I could not figure out why they were off 6 mph. It turned out the one gun was angled about 10 degrees because they were held together. I then held each gun in each hand, so they were pointed straight, and they were both dead on. It is simple trigonometry. The angle of the gun represents the hypotenuse of a right triangle. If you held the gun to the side as the car passed, it would not register a speed, because the car may be going 70mph, but its closing speed to the gun is zero. As you rotate the gun to the path of the car, you start to capture the speed until ultimately, you are directly in front of it, getting 100% of the closing speed value. They teach this to Police, so they can get the highest reading. That is why they always try to get the straightest shot on you. Otherwise, they would hide behind a blind bush or bridge, and just pop you from the side. One last point. When Dale Earnhardt hit the wall, his car was going about 190, but because of the trajectory he was on, his closing speed to the wall was only about 39MPH. Same principal, but the math is backwards. If he would have hit the wall dead on, he would have hit it at 100% of his closing speed. The simplest test is the gun in the car trick. Trust me on this one. You'll get better numbers.
Posted on: 9/16/2008 3:32 PM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7960400

RE: Going For 70+MPH OR DIE TRYING..........
By the way, I just watched the video of the 71mph Baja, and it actually went faster than that. Have the radar gun operator aim for the car about 50 feet in front of him. You will get a straighter shot. Right now, you got about 95% of your actual speed. If you want to test this, aim the gun straight out the front of your car, then take another read with the gun turned about 10 degrees to the side. It will be less. So load up, make another pass, and rename your post Going for 75+MPH or die trying....
Posted on: 9/16/2008 2:30 AM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7958915

RE: Going For 70+MPH OR DIE TRYING..........
Nice Baja, Miami. Did you pick up a lot of speed with just the bearings? I have some aftermarket bearings on my FG comp, and they have a bunch of drag when cold, but they loosen up when they get hot.
Posted on: 9/16/2008 2:21 AM by Author "tonykalil" in the forum "RC Giant Scale Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7958903

RE: Difference between Tamiya and HPI Toyota GT1
700 hp in 1980 lb car must be insane
Posted on: 9/13/2008 4:43 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7949356

RE: Tamiya TG-R
I'll have to look. I don't think I even have a car with the stock rear uprights. I think they are zero, but I can not be sure. Sorry, will take some for you. I just found another TZ on ebay for under $120. It is the rotary carb, no pull start version, but it was cheaper than a new piston/sleeve plus carb. It could fit in a TGR since I have a start box set up for 2 of those cars.
Posted on: 9/13/2008 4:38 AM by Author "tonykalil" in the forum "RC On Road Nitro Cars"
http://www.rcuniverse.com/forum/fb.asp?m=7949349