Landracing Forum
Tech Information => Steering - Suspension - Rear End => Topic started by: jww36 on August 30, 2011, 11:37:17 AM
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OK guys (and gals), I need some help. As documented in my Build Diaries (1934 Gas Roadster), I spun my roadster at Speedweek. Without ANY warning or indication what so ever, the car snapped left into a spun. I was on it pretty good, so I am certain I spun a tire or tires. MY QUESTION - If the car spun to the left, with a spool rear end, which tire would have broken loose to spin in that direction?
John
#114
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With a spool both would break loose, the torque reaction and nosing over when the wheels started to spin and maybe a little driver reaction over steer could have caused it. There are several variables including a cross wind. What mile and what speed were you at when you got the 360 degree view of Bonneville? Hope the car is OK.
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Though I am no expert I am curious about the comment "without any warning". I noticed in your build that the car was very loose, did you add weight? We don't run any suspension, but the first thing that came to my mind was if this is a suspended car maybe if you added weight it loaded the suspension and during the run one side un-loaded. Once again I am no expert just another idiot with an opinion.
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Remember circle track guys use caster and scrub radius to weight jack their cars to come off the corners better :-o
[sorry for using camber before]
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The only time my car went around I didn't recognize the warning. Looking back, it was there, but I didn't see it until the car had taken over. It seems that in your question if the left tire lost traction/drive. The right tire would push it around. But I don't have enough experience to do more than guess.
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As I commented in your build dairy [observed lots of loose salt on course #1 after meet and before moving course over next day]
If your left tire was in loose salt your right tire would have more traction driving car left.
JL222
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Thanks for the input. I just took the car off the scales.
Left front 639 lbs.
Right front 630 lbs.
Left rear 875 lbs.
Right rear 909 lbs.
Total weight of car with driver 3053 lbs. TOO FRICK'IN LIGHT??
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Way too light.
Another '33 roadster has a 1/2" steel floorboard.
DW
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John - You have to remember IT"S A ROADSTER!!! - speaking from expierence, they do that to you just because - - -. As Ken Shrader sez " You get a little behind in your steering (even if you don't know it) and these things happen" - All kidding aside - weight can be your best freind - :-DPat
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We all need to remember that at the traction limit it only takes a very small offset force to cause a car to spin. I was talking with Neil with the Contrivance Engineering roadster and he was saying that his data was showing a coefficient of friction for the salt of .3 and looking at your rear wheel weights the right rear has 34 lbs more load which would make it generate about 10 lbs more forward thrust which, because roadsters have pretty wide rear axles, could be more than enough to cause you to spin. Adding weight will get you more traction and if you add enough it will get you away from the traction limit where this problem occurs. You will still need to really get your corner weights close.
Rex
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John - As I said in your build thread, I think you need a bunch more weight, and probably a greater rear percentage. With the C engine (SB2.2) in the rear-engine car, we're a shade over 3900 without the driver. It hooked up well and ran 254 (all it was geared for). vic
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I would like to see Glens question answered, how fast were you going and also what gear and how fast have you gone? That said with having never checked your build diary I have two thoughts, more ballst, and I would not get in your car again without confirming equal runout of the rear tires. My 2 cents. Vince
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IF you have a good bit of caster and a good bit of + scrub radius if it baresly started left and you coreected you would have put more weight on the RR which would have driven you left
There have been several very detailed post on this before!!
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Torque Steer really does create an uneven drive situation, especially, it seems, in Roadsters. During Speed Week I reinspected a roadster that had spun a number of times at 215-220 mph. The Team had a Video camera and finally observed the driver having significant steering input in one direction. The answer was to preload a lower rear four link bar a-la the Drag Strip, and go to a taller rear gear and sprung rear suspension. The car was finally able to be run through the 5 mile, and ran 240......Pretty sure there was more weight put in as well. Your tresults may vary, though. Roadsters vary hugely in their aero footprint, but it is curious that every Roadster I reinspected after spinning did so at that same speed....215 or so..
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Have any roadsters tries IRS so driveshaft torque doesn't load the left rear . A single torque arm to the paseger side of the driveshaft with the offset and length ratio the same as the ring and pinion does the same thing .
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Thanks for the input. I just took the car off the scales.
Left front 639 lbs.
Right front 630 lbs.
Left rear 875 lbs.
Right rear 909 lbs.
Total weight of car with driver 3053 lbs. TOO FRICK'IN LIGHT??
Just an observation, but your wedge/diagonal should have made the car turn left.
LF 639 + rr 909 = 1548
rf 630 + lr 875 = 1505
this shows 1.4% wedge turning the car left.
It is not much, but still there.
Just another opinion, J
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If any of you followed the building of this roadster in "Build Diaries", you'll remember I threatened to write a book, "How a Newbie Gets Started in LSR and Wants to Build His Own Car"! I thought after the car was built, the book would be done. NOT! The next chapter, and it's going to be a long one, is "What in the Hell is Wrong With My Car, and Why Does it Want to Spin".
Seriously, I appreciate all of the input, and I'm sure I'm not the only LSR following and learning from this topic. I'll try to answer some of the questions, and then I want to follow up on a few comments.
When I spun, I was in fifth gear, on it hard as I have mentioned, at the 2 mile. If I had to guess, I'd say I was around 200 MPH. As for my experience, I've got less then a dozen runs in total at El Mirage and Bonneville. But in those dozen runs, I have never once spun the tires or lost traction in acceleration. I have always driven this car and the Barbee Boys roadster (227.8 MPH in 2007) as if I had an egg between my foot and the throttle pedal.
Kiwi Paul mentioned preloading a lower rear four bar which is something I've never heard of, but then I'll admit I know as much about race car suspension and setup as I do about brain surgery.
The other interesting comment was about diagonal weights. The thing that will make both adding weight to this car and being able to adjust that weight is I have access to setup scales, and more importantly, I plan on making a mold for the ID of my 2" x 6" lower frame rails and sliding the weight inside the lower frame rail. In this way the weight is contained and adjustable. Once I get it where it needs to be, I can put a bolt thru the frame rail to keep it from moving forward or back. All it takes is time.
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Have you checked the tire roll out??
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Glen;
If you're refering to the run out, I spent alot of time truing the wheels and then truing the tires after mounting, and then balancing the wheel/tire after tire truing. As far as the circumfrence of the rear tires, I used a tree tape to measure them and adjusted the air pressure (8 PSI) to make them equal size.
John
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It is very interesting how many different things can and do affect the possible reasons for a roadster to spin on the salt. John, I know on your last run that your replaced the rear shocks and springs with struts so the spring rate of your suspension, not counting the tires, was effectively infinite. Now only your tires were acting as suspension, and you have set one of them 8 psi higher than the other to balance the diameters but now you have increased the spring rate on that tire possibly by as much as 10% (this is based upon some tire data that I have for some road racing tires and I am not sure what the inflation pressure vs. the spring rate is for land speed tires.) This means that this tire will be carrying a larger percentage of the rear weight. Did it happen to be the right rear??
I have also done some "pie in the sky" calculations regarding rear weight/salt coefficient of friction/available hp and with your present rear weight about the maximum hp that you can apply to the salt without spinning the tires is around 520 hp (this is at 220 mph) if you increased the rear weight from the present 1800 (approx) lbs to 2500 lbs you could apply about 590 hp which if you take into consideration the altitude and air density, drive line loses, rolling resistance etc is pretty close to what you have for available horse power. These calculations have nothing to do with anything aero which means that if you bump against the "aero wall" where forward thrust equals aero resistance the addition of extra rear weight will not make you go faster than that limit. At that point you need to A. Make more hps or B. Reduce aero drag.
Rex
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You could use the search engine in this site and find a lot of information on roadster set up and spins.....rather than go through it all again I will summarise....run a spool...put enough weight on the rear end so that you don't have to peddle in second gear.....
if the rear tires are rolling (not spinning or slipping) you will not spin out!
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Rex, why would hp be a load indicator? Shouldn't it be X torque at the tire contact patch? Just wondering, it's like a guy saying his trans is good to 1000 hp. Not so as 350 lb/ft @ 15,000 rpm = 1000 hp and trans would probally live but 850 lb/ft might kill the trans (or break the tires loose) but still make 1000 hp as you well know.
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Roll out = tire circumfrence ie how far they travel in one complete revolution. If you have slightly different tire circumference, due to the physical tire size, its loading and tire pressure, with a solid spool the taller wheel will be constantly trying to turn the car toward the shorter drive wheel, as it will travel slightly farther with each axle revolution.
Lots of issues that interact here.
For example the Ack Attack motor cycle had problems at last years shoot out, it kept pulling to one side, and they eventually figured out it was due to a tire that had a slightly off center crown on its tread, so it wanted to lean the bike to the side slightly at speed. They replaced that tire with another that was known to be good and the bike ran true and went out the back door at about 394 mph.
It does not take much to upset a vehicle that is on the ragged edge of traction and pushing a large aero load that is in front of the center of mass. As soon as that center of drag gets just slightly off to the side, and the side force exceeds your steering/lateral traction on both axles, it wants to push the car around and there goes your snap spin.
larry
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Front wheel drive cars rarely if ever spin .
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Mike,
What I look at is the rear tire weight of the car, lets say in John's case, 1800 lbs., then look at the maximum coefficient of friction between the tire and the salt, let's assume .4 for grins, .4 x 1800= 720 lbs of thrust. Now we can take the "James Watt" definition of horse power, i.e. 1 hp= 33,000 lbs of force over a distance of 1 foot in one minute. Divide by 60 seconds/min and you get 550 lbs force/second. John's car is making 720 lbs of force so I divide 720 by 550=1.3091 hp/ft/sec. John is going 220 mph so now I multiply the 1.3091 x 220 x 5280(this gets it to feet/ hour) and then divide by 60 gets it to feet/hour and divide by 60 again gets it to feet/sec. So we have a force in pounds going in feet per second which equal horse power. In Johns case the number is 422 hp, this is the maximum horse power that can be applied to the salt with this rear wheel weight. I happen to know that John's motor is good for around 850 hp at STP so at the salt it is probably good for around 720 flywheel horse power (I used a .85 multiplier to adjust for the altitude, a WAG on my part) Now if you look at the 422 hp that John is limited to because of the lack of rear weight, and use a drive line efficiency of .9 and a rolling resistance of .9 you get a flywheel horse power of 520 hp. So John has (using my numbers an additional 200 hp available at 220 mph. So torque in this case is not looked at as hp is a measure of work and when you are going 220 mph your motor has to work, and pretty damn hard.
Rex
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Rex. I like your explanation and then your calculations on how you got there. The part that interests me is where you say you need more horspwer but don't have it or has it but can't apply it.. For more of a non-aero car that makes complete sense as "when" a roadster wants to spin.
A 34 grille shell may go thru the air better than a 29 or 32 but none wants to stop accerlerating. A Camaro/Firebird style vehicle many never feel his car wander like a standup roadster or at least not to the same extent.
John W has learned a lot in a short time and will continue to as all of us with roadsters. I'm glad this doesn't happen much at slower speeds.................Good Luck to all
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Thanks to everyone for all the input. Now my head is spinning!
Weight distribution question - In balancing the weight in the car, do we want a liitle more weight on the left rear to compensate for the torque wanting to "roll" the car to the right rear?
John
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If you have low rate springs in the front(or coil-overs close together) with no sway bar in the front and low rate springs in the rear with a stiff sway bar in the rear,.... all the torque is in the rear sway bar, the body will roll but the weight on the rear tires will not shift side to side!!!
....in fact you can lift one of the front tires off the ground and see almost no shift in the rear side to side distribution!!!!!!!!!!!!!
That is the way the contrivance special is set up
Akk
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"this shows 1.4% wedge turning the car left.
It is not much, but still there.
Just another opinion, J
I personally like some wege on the Lf-Rr so that the drive line torque is somewhat nullified under way---but I am a "no Suspension" Torsen loving , "lakester guy" :-D lol
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Just to throw another wrench in the mix, how are your shocks (valved) set up? If you have adjust ability, here are some things you can do.
Low speed rebound will help with driver feel and keep the platform stable. Going too aggressive will make the car feel harsh and choppy.
Low speed compression (bump) will help with getting the tires up to temperature quickly. This basically helps to control how the unsprung weight of the car is controlled. Ideally, you want to run as much as possible to where the car is not unsettled on the larger bumps on the salt.
High speed rebound helps control the spring and how the body is moving after hitting the larger bumps. You want run as little as you have to, so the car doesn't "jack down" while going down the track.
High speed compression if set too aggressive can launch your car when hitting the larger bumps on the salt. You want to try and run much as you can get away with. But be very careful when going firm. Tony
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Am I the only one who has extreme issues at the 3 1/2 on the long course? This happens at around 195 and I have short shifted or coasted for the shift in that part of the course to try and avoid a HARD snap to the left. We added 500 pounds of lead in the back in attempt to avoid this, but I'm afraid this might be destroying the "lawn dart" effect that may have kept me from crashing before. I guess I'll see in September!
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Where in the back did you put the weight, in front of the rear axle, over the rear axle or behind the rear axle?
Does that snap to the left occur when you get back on the power?
Larry
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It does not take much to upset a vehicle that is on the ragged edge of traction and pushing a large aero load that is in front of the center of mass. As soon as that center of drag gets just slightly off to the side, and the side force exceeds your steering/lateral traction on both axles, it wants to push the car around and there goes your snap spin.
larry
I don't know roadsters at high speed, but I know canoes at low speed. One very effective way to steer a canoe is to add a little drag on the side you want to steer toward. Maybe the offset cage is a constant drag just waiting for the ragged edge condition hotrod described to make its contribution.
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Interesting idea. Rudder effect as with a plane or boat. Even more-so with offset windshield.
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Interesting idea. Rudder effect as with a plane or boat. Even more-so with offset windshield.
Interesting Ideas. I was looking at 911 last night pondering this same thing. Driver offset to the left, big ol mags hanging out the right. Might be helping balance the aero?
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The Barbee Boys roadster (driver on left) was prone to want to pull to the left. Someone told them a year or two ago, it was an aero thing because of the driver wind screen, cage, etc. on left side. What I did to anticipate that was put the slightly taller tire on the left rear. During my runs, my car did not seem to want to "pull" one way or the other as far as drifting goes. But it did want to "dance" or "float" as previously mentioned.
As far as coil overs go, on Monday @ Speedweek, I took the coil overs off and put solid struts on. No rod ends on struts so they really made for a solid rear end as they eliminated any side to side movement as well. If I do go back to the coil overs, I will go to a Watts Link set up and sh.t can the panard rod.
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As John W mentioned the off center cage moves the center of drag to the left . Drive shaft torque tries to loads the left rear tire which puts the center of thrust to the left so one tends to cancels the other . When thrust changes that upsets the balance .
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If you have low rate springs in the front(or coil-overs close together) with no sway bar in the front and low rate springs in the rear with a stiff sway bar in the rear,.... all the torque is in the rear sway bar, the body will roll but the weight on the rear tires will not shift side to side!!!
....in fact you can lift one of the front tires off the ground and see almost no shift in the rear side to side distribution!!!!!!!!!!!!!
That is the way the contrivance special is set up
Akk
Hi Akk,
Could you give me a ball park idea of an effective in/lb spring rate for a rear sway bar?
Thanks,
Skip Pipes
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Skip,
design the sway bar with as large a dia as possible. Look at Sprint car setups, 1 1/4" dia.
Use a hollow bar and you will have the ability to stack up 2 bars.
Another issue in suspension would be the end stops of travel. Having the suspension move to the end and get hit with a infinite spring rate (solid) will introduce a wild ride.
FWIW, I like Burks idea of a IRS to isolate the driveline torque from the rear axle/wheel loading. Brings back memories of stuffing higher rate springs under the right side of the nova to launch it straight.
J
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Skip,
Working from memory the front coil overs are 275#/in each spaced about 16 in apart... the rear springs are not on coil overs (using jack screws for easy adjustment when adding weight) 500#/in each...the sway bar in the rear was the stiffest I could fit 1 1/8 hollow from speedway (I think?).
What is important is the lack of sway resistance in the front. The rear will absorb engine torque regardless of the stiffness of the sway bar and rear springs. The stiffness of the sway bar just determines how much the body will roll for a given engine torque.
If the front doesn't resist body roll, the weight on each of the rear tires is not affected by engine torque!!!!!!
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One thing not mentioned [I think] is how cars become unstable with lift and roadsters might be worse than others.
I've posted before how Jim Hall [Chaparrall] and Chevrolet were one of the 1st to use spoilers to prevent
hi-speed instability not allowed on roadsters though BUT Shane Mcgann's 243mph D blown street roaster
has the stock rear fuel tank 8-)
A combination of lift --loose our wet salt on one side our both could cause loss of traction and tire spin which causes an oversteer condition.
I noticed when we washed the car, a salt build up around front and back of the rear valve stems [1/4-3/8''] must have been from wet course on friday never happened before
JL222
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In an effort to tighten up incorrect use of vehicle dynamics technical terms, note that “oversteer” and “loss of traction” or “tire spin” cannot coexist. While loss of traction may well induce an uncontrolled yaw motion of the vehicle (spin), that motion is not oversteer.
Oversteer is a condition that arises from mismatched slip angles of front and rear tires before they break loose, and is a result of the elastic deformation of side-loaded tires.
Troy, see Jim Hall’s primer on vehicle handling (or any other vehicle dynamics reference).
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Shaen Magan. Reply #40.
DW
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And the answer is . . . ?
(Or the question.)
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Oh, damm, I couldn't hold off any longer!
Here's some numbers I know:
San Berdoo Roadsters Street Roadster . . .
1 D/STR BV record, 4 C/STR BV records
111" wheelbase
2800 pounds
45/55 weight distribution
250 pounds more on the left rear than the right
Open rear end
210 MPH - never spun except one run with a posi.
Steve Batchelor's Monza
Owned the BCD/Classic Gas and Fuel Altered records (go ahead and look)
Same engines, shorter wheelbase (100"?)
2800 pounds
40/60 weight distribution
Open rear end
245+ MPH - never spun
According to present knowledge, we were doing lots wrong(?).
Stan Back
(Something to be said for 1/2-length pitman arms.)
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Looks like this is becoming one of those blind men and the elephant topics!
Hey, Landracing I weren't DONE!
Stan didn't mention his near 194 ElMo record or the easy 190 pass this year @ the same event the former BV record holder did another of his spins.
I are done now!
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I posted some thoughts on this somewhere else on the Forum, but since Shaen Magan`s Street Roadster was mentioned, I can tell you that the crew were very excited to be able to apply some chassis preload to the rear four link, along with a sprung (changed from solid) rear end and a taller gear, and were able to get the car through the 5 for the first full pass, instead of having it spin repeatedly at 215-220. I don`t think this is a cure-all, as all roadsters really vary ALOT and Stan Back`s experience is just as valid as Shaen and crew, but after helping with reinspections at Speed Week this year, I can`t help but observe that alot of those Roadster spins are happening at about the same mph.......anyone else? :?
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Ok here I go. Stan Back is one of my best friends. What works for him is not what works for me. He has more records than I will probably ever get But! My roadster has no rear suspension, I run 70psi in one rear and 60 psi in the other. I have 12 passes between 200 and 215, ( not many) I run a spool. I have never spun. 3500# when it leaves the line, heavy on the rear, close side to side. I have heard the story of roadsters becoming evil when you run out of power. This has never happened to me. Best pass 214 the next day 215 with a 216 exit I thought she was wanting to kill me. My car is center steer. The fastest roadster in the WORLD has NO suspension. Vintague Hot Rod has been running roadsters for 20 years and never spun, no rear suspension ever. Al Teague ran 267 in about 74 with a stock wheelbase stock body Model A with a solid mounted rear end and a buggy sprung front end. Stan is right, Al Teague is right, Vintague Hot Rod is darn sure right and I am right. We all have Red hats in roadsters and all got there with something different. I set my car up with a tape measure and a plumb bob. Scrub radius? other things mentioned here. beyond me. Lean the front axel back as far as you can, make sure it is square, make sure the rear tires have the same runout, and sorry Stan put a spool in it. I have found with my car if the steering wheel is doing something more than providing my left hand something to hold onto it is not going to be a good pass. When the starter tells you to stay to the left or right side of the course just smile and remind yourself its a roadster and that the goal is to go through the 5 between the markers, pointed the right way and your foot IN IT. Ten people are going to tell you I am on Crack. Good Luck Vince
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Vince. Congratulations on your "hat" and doing it with a Skinner/GMC. I think that's 7 of us all with a little help from Joe.
I agree with the center steer; it's been working on our car since 1971. We have used solid mount with a spool, coil over with a spool, parallel leaf & open and only spun because of stupidity of the rebuilder (me) at 185. We keep the movement on the rear axle to 1/2". Only ran out of hp once and I had that ride but did not spin it. Hopefully we will see 200 again but 170 you are right about a place to rest you left hand while waiting for the finish. If they are right they are a pleasure to drive.
Once again congrats on the hat......(Skinner with all the trimmings on the shelf too).........................JD
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Am I the only one who has extreme issues at the 3 1/2 on the long course? This happens at around 195 and I have short shifted or coasted for the shift in that part of the course to try and avoid a HARD snap to the left. We added 500 pounds of lead in the back in attempt to avoid this, but I'm afraid this might be destroying the "lawn dart" effect that may have kept me from crashing before. I guess I'll see in September!
I'm done Shifting when I pass the 1 mile marker and I always know I'm going to have turbulence at the 2 1/2 and the 3 1/2 when I'm over 210 mph (under 200 mph its just a sunday drive). I've been told it's a wind vortex blowing between the mountains. One spin at the 4 mile at 222 mph in 2010, spool, loose salt, HP, and too lite in the front, I think. Added 130 lb to the front, behind the front axle, help handling alot.
Richard
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Vince is right.
I've experienced the "notch" once years ago. I think it's real. And the location varies with the course layout and the wind direction. I stay to the left all the way down (if I can), 'cause it takes you to the right.
But I guess my point (not very well made) is that simply adding weight and measuring side to side and front to back and calculating wind resistance side to side won't fix a car that has inherent problems. A case in point was a new roadster I observed at SpeedWeek. Scary at 130. Very well constructed with high-grade street rod parts. Thousand pounds more than ours and they were gonna add weight to fix it.
I also subscribe to AKK's formula expressed here a few months ago -- and their results sure speak for how it works for them -- keep adding weight 'til it won't spin the tires in 3rd. Led to real funny weight distribution (80/20 in AA?) and their own page in the Rule Book.
As JD says,
"Good Luck"
Stan Back
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Vince. Congratulations on your "hat" and doing it with a Skinner/GMC. I think that's 7 of us all with a little help from Joe.
I agree with the center steer; it's been working on our car since 1971. We have used solid mount with a spool, coil over with a spool, parallel leaf & open and only spun because of stupidity of the rebuilder (me) at 185. We keep the movement on the rear axle to 1/2". Only ran out of hp once and I had that ride but did not spin it. Hopefully we will see 200 again but 170 you are right about a place to rest you left hand while waiting for the finish. If they are right they are a pleasure to drive.
Once again congrats on the hat......(Skinner with all the trimmings on the shelf too).........................JD
Thanks JD means a lot coming from you. There is not another group of people on earth I would rather be assosiated with. Joe is a treasure, he was in my push truck when they sent me off on my return. See you in October. Vince
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The Jesel roadster spun every run at speed week and they said they can't find the reason and will retire the car. BTW, it spun to the right each time.
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Tell you what, I'll ask Wayne if he wants us to test the motor and see if it's the problem.
Stan Back
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The Jesel roadster spun every run at speed week and they said they can't find the reason and will retire the car. BTW, it spun to the right each time.
It just might be this years course conditions or wet or loose salt, the 222 camaro has always felt comfortable at speed 200-300,
[glued in], this year no traction and felt real loose, like it could swap ends at any time and did :-P :-D
Data logger shows 100% throttle in high gear last year and 318mph at end of 1st mile. [294 avg]
This year 48% throttle and spin at 270 -280 mph.
We took videos of data logger and if they come out OK Bville will post in our build diary and maybe here to show course conditions.
JL222
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JL
This car has a history of spinning, last year was the only year it didn't spin. They thought it was fixed but the problem returned this year. A lot of people looked at it with no understanding as to why. I talked to Wayne and it's to the point of being dangerous as it was up on two wheels this time when the chute caught it.
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Glen--Since Wayne is going to retire the car, have him give it to you. Then Stan Back and yourself could discuss and implement the necessary fixes. I`d volunteer to drive, if needed.... :evil: :evil:
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I wouldn't count on the "retirement" of the Goldstrom & Jesel street roadster. It is very unlikely a team with the resources and success in other classes will throw in the towel, just rethink the problem would be my guess.
As has been stated, many ways to skin a cat er... roadster.
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Which would be my point, actually.... :-D
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Have they tried different drivers? Just a thought, don't want to upset anyone.
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Sometimes the easiest thing to change is the "nut behind the wheel" steering wheel that is!
Rex
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I gotta ask, who was driving the Jesel car this year..................I think I know the answer.
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Jimmy Shine was the driver and he's seen much more success than the previous driver. As big a jerk as I am, I don't think it's the driver.
Stan
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The spins this year were after he lifted, (did not drive into the chute)
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Jimmy Shine was the driver and he's seen much more success than the previous driver. As big a jerk as I am, I don't think it's the driver.
Stan
At least he's consistant year to year! :-D :cheers:
Yup, that was my guess. :evil:
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He held on to nail the record a year ago, I think it was. We had it off and on in maybe for the last 8 of the 10 years, off and on. Now it's 20 MPH faster. Still think we have one of the best set-ups out there. But with our '92 motor, we may be lagging on the HP end.
The coolest thing is getting it back.
Stan Back
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Hey Stan, don't be bad mouthing their "PREVIOUS DRIVER", another San Berdoo racer from MY day!
Yer's truly's bettin' on the car, though.
Maybe it's the cam drive! (Only the world's best).
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He held on to nail the record a year ago, I think it was. We had it off and on in maybe for the last 8 of the 10 years, off and on. Now it's 20 MPH faster. Still think we have one of the best set-ups out there. But with our '92 motor, we may be lagging on the HP end.
The coolest thing is getting it back.
Stan Back
...............records I guess , in that way, are a little like the reproductive act, sure , you can keep breaking your own "mark" but there's nothing like a little "to-and-fro" to keep it interesting. :-D
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Trent, if you only know Jimmy from television, that's one thing. He's always acted real good around me. His Dad was a friend of my Brother's 45 years ago and a genuine hot rodder. By the way, it was good to see you again at Speedweek this year. :cheers: Wayno
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He's the tatood guy with his hat pulled own to his ears.
Jimmie JESSIE!
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Trent, if you only know Jimmy from television, that's one thing. He's always acted real good around me. His Dad was a friend of my Brother's 45 years ago and a genuine hot rodder. By the way, it was good to see you again at Speedweek this year. :cheers: Wayno
Never saw him on TV. In fact we don't have TV! :-D He spent some time around us when he was here in town a few years ago. :wink:
Yes, it was nice to chat again albeit briefly.
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He held on to nail the record a year ago, I think it was. We had it off and on in maybe for the last 8 of the 10 years, off and on. Now it's 20 MPH faster. Still think we have one of the best set-ups out there. But with our '92 motor, we may be lagging on the HP end.
The coolest thing is getting it back.
Stan Back
There any current pictures of your car? I think I have one saved but cant find it.
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http://www.jalopyjournal.com/forum/showpost.php?p=6550072&postcount=11 (http://www.jalopyjournal.com/forum/showpost.php?p=6550072&postcount=11)
Mike
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Thamks Mike, I remembered that thread but did not go looking for it yet! :cheers:
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I gotta tell you, the internet is a marvelous thing. I'm mathmatically (among other things) challenged, and I was trying to come up with a formula to give you weight percentages on my roadster (front to rear, etc.). I realize now it is a simple formula. But when you don't yet have that formula... well. So I go online and ask Google to find the formula for me, and boom we're good. But better yet was a go-kart website (yes, go-kart) I found that literelly did it for you. It asks you (input) Total kart weight. I put in 3500 pounds (world's heaviest go-kart), as that is what I think total weight of my car should be after adding weight. It then asks % front, which I input 45%. It then asks % left, which I put in 52%, and then it asks % cross, and I input 51%. Press Enter and Bless you Baby Jesus, it not only shows weight of each corner, but also percentage of each corner. In my case 806.4 on left front (23.04%), 768.6 on right front (21.96%), 1016.4 on left rear (29.04%), and 908.6 on right rear (25.96%). What all these numbers mean and how they will balance the car, I don't have a frick'in clue! But it does give me something to think about at 3 o'clock in the morning between pee's.
John
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I'm glad to hear you need to pee at 3 am every moring too! Thought I was the only one....
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1am, 3am 5am, if you only get up once you are lucky. :-o
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Ever notice how some of these threads can swing off on a tangent that has nothing to do with the subject. I really don't care how many times Fred gets up to pee at night!! BTW it is twice for me.
John your car is so close to really setting some records just a little more tweaking and you will be in impound for sure!! I think that the reason that your car felt better on the 219 run with the solid struts in the rear was because they canceled out the affect of that broke back panard rod you have. Going to a watt link is a good idea.
I still think that you need to block off the grill and make your air inlet about 2 inches by 4 and you will pick up an easy 5-10 mph. Love your car.
Rex
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But it does give me something to think about at 3 o'clock in the morning between pee's.
John
Look at how many of my posts are between 2--4 am ---lol
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I'm always surprised at the number of people from the North American time zones who are on in the middle of the night when I run out of sleep and turn on the computer. :| :| :|
Pete
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Unfortunate that a simple addition to improve direction stability is just not practical in any chassis I can think of: a simple inertia gyro, perhaps built into a vertical wing (tail). Wheel OD can be larger than the tail height if the lower portion is inside the bodywork. Total mass is low, all weight at the rim, strong axle and bearings.
Pre-spin it up to very high RPM with air pressure before starting, might continue to spin for several minutes.
Resists yaw and roll very strongly, completely passive in accel & decel, bump & rebound, and pitch. Maximum yaw control ~ how far back you can place it (ahead of the nose works equally well, but the CP of the gyro should be reaward). Max roll ~ how high above the CG.
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Unfortunate that a simple addition to improve direction stability is just not practical in any chassis I can think of: a simple inertia gyro, perhaps built into a vertical wing (tail). Wheel OD can be larger than the tail height if the lower portion is inside the bodywork. Total mass is low, all weight at the rim, strong axle and bearings.
Pre-spin it up to very high RPM with air pressure before starting, might continue to spin for several minutes.
Resists yaw and roll very strongly, completely passive in accel & decel, bump & rebound, and pitch. Maximum yaw control ~ how far back you can place it (ahead of the nose works equally well, but the CP of the gyro should be reaward). Max roll ~ how high above the CG.
I'll take two smaller ones :-D
JL222
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Rex;
I really appreciate all of yours and other racers input on this question and on my Build Diaries "1934 Ford Gas Roadster". As a LSR newcomer, I learned an important lesson at Speedweek. You can build a nice car with all the power in the world, but if you can't keep your foot hard on it, you're not going to be competitive. I knew my car was light, but I was hoping the body rake would add some aero down force. But that's one of the problems with aerodynamics. Unless you have access to a wind tunnel, you're kinda guessing as to what the air is doing around and over the car. We're going to run November El Mirage, and we're going to put some yarn tuffs on the car and video record their movement. Like I've said here before, I'm not sure what it will tell us, but it sure might make interesting conversation.
John
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But that's one of the problems with aerodynamics. Unless you have access to a wind tunnel, you're kinda guessing as to what the air is doing around and over the car.
This is about a roadster right? when I hear roadster and wind tunnel, I think of Mississippi state fair and formal wear. :-D