Landracing Forum
Tech Information => Technical Discussion => Topic started by: hotrod22557 on March 22, 2010, 07:37:52 PM
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Hello All.
I am an absolute virgin to LSR but I am building a Comp Coupe car....because it is on my bucket list! I want to go 250 at Bonneville before the checker falls. I am an engineer working in NASCAR Sprint cup so I have a lot of resources available and have been in the roundy-round racing game for a long time. (BORING!)
The car is coming along nicely-all tube chassis, IFS, all the latest NASCAR safety stuff. Lots of dumpster diving after work. I am calling in a lot of markers to help out with the build-especially all my aero buddies. Aerodyn is 1.2 miles from the house and a bunch of gear heads work there too. Maybe a midnight shift or two to help sort out the body.
I am ready to buy tires and wheels now. I have talked to the NASCAR Goodyear racing engineer and he says that the Drag 24.0-4x15 front runners will be fine for 200 MPH +/- while I shake the thing down and before I bolt in some real steam! For rears I do not have a clue and need some direction.
I am looking at extreme performance street tires with a Y rating (186 MPH) like the Continental DWS supercar tire. I will be running Maxton before I head west in 2011. Some friends tried running CUP tires at Maxton but could not hook them up. I think an aggressive open tread will help with grip on the salt and at nasty old Maxton.
Thanks for listening to my ramblings but I sure could use some good advice.
Thanks again!
:cheers:
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Hotrod, welcome to the LSR site. A few questions from this side. First a name, 2nd what part of the country are you in, 3rd. Do you have a current SCTA & ECTA rule book. Nascar safety does not always meet our safety rules. What kind of body are you using for the class you want to run. These are things we really need to know in order to help you with the build. SCTA is very strict on the tire requirements and in most cases grooved tires don't work all that well on the salt. Not trying to discourge you we all want to help. Let us know and I am sure others will be asking some questions for you. Good luck on the build.
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Glen,
Thanks for the quick reply.
My name is Mark and I live in the Charlotte NC area.....home of all the NASCAR teams. Maxton is 2 hours away.
Yes I do have a 2009 SCTA and ECTA rule book and have been following them closely. I have a lot of experience reading rule books now that NASCAR writes its rules in legalspeek for liability protection. I am keeping complete documentation (written notes, calcs, drawings, photos, material certs and receipts) if they are needed. I do need information on the "log book". Is it a formal book sourced from SCTA or is it simply a buid history of the car? What is the required format if any?
The cage is 1 3/4 x .120 wall mild steel (Rule is 1 5/8" but that is an oddball size here in NC so I used 1 3/4 because I have access to the bender at work). The body is a 1959 Nash. The wheelbase is stretched 24" and the roof slammed to maintain the 5" min windshield rule. Right now I plan on running the factory front sheetmetal (fenders and hood) and see how it goes. I can always build a nose in the future if is not slick enough.
As for the tires I placed a lot of thought on longitudinal traction. Am I sideways on this?
Thanks again
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SCTA has a standard logbook -- and the ECTA now sells those (instead of the "old" ECTA book). Get one -- for ten bucks -- and you'll have room for many, many events, room for inspectors to note thing that you should or might need to change, your comments, and so on. It's a requirement to have a logbook. SCTA ones are issued with a land speed racer chassis sticker to be affixed to your vehicle - and the book has the same number imprinted -- so the two stay together and th ey notes on what you did -- are always available to you and to the inspectors.
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Call your markers:
LSR Goodyear 300 MPH rated go from 21" to 28" on 15"
My suggestions for your build:
very frame Rigid
watch your scrub radius
aero front end lift
AND put 3 roof spoilers 45 90 45 so if you do go round
because-- :evil:-- as you know around 190 up even bricks can fly :-D
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Mark, see how fast replys are. You are going the right direction. Keep it up.
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Mark,
I am near you,, I have an office in Salisbury and I live and have my shops in Midway/Welcome NC area.
I have 2 LSR Cars... a 1933 Ford Victoria and a 1953 Studebaker Coupe (still in final 6 weeks of a year plus build process) I run at Maxton and will run the 1.5 mile at Loring this year,, if my lil 255 cu. in. "E" Motor goes 200 at Loring, I will make the trip out west to Bonneville this year,, if not next.
email me sometime,, be glad to hook up and talk,,
Charles Venable
Venable Rods and Racing
cajunkid5690@yahoo.com
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Mark, you didn't mention what motor you were using, but if it is in the 250 MPH class, for the salt, the tires must be rated for that even if you go 160. Take Sparky's advice, get LSR tires if you can.
Don't know what is required for Maxton, but I know someone will chime in on that one. Joe T?
Remember to have fun.... 8-)
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Just to add on to Stainer's reply -- in SCTA you must build the car to the Bonneville class record that you're entered in. Doesn't matter if you got a slower car without the potential (you think), you must build to the class record with roll bars, tires, fire suit, etc.
Stan
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All,
Thanks for all the quick replys.
So if the class record is 175MPH Y rated tires will be OK? (Y is rated at 186). I b uilt the chassis/cage for the high end of the class even hough it will take some time to get there...if ever. But I willo back and review it again.
Power is TBD (maybe another marker) obsolute 800 HP cup engines are like cord wood around here...they are everywhere. But I was going to start with a little 5.0L small block or maybe something even smaller based on budget.
A friend at work wants me to run a 2.0L Toyota turbo engine that he has in his garage sitting under his bench.
Engine choice will be down the road a bit.
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If you want to go faster you might as well get use to the seat"feel" with as close to the final configruation as possible
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Mark,
With the abundance of 800 HP Cup motors around your area,,, how about arrange for a 302/305 cu in Small Block Chevy with 700 + HP to fall off a truck and end up in my garage,,, I need a "D" motor !!!!
(I have a 255 cu in "E" Motor and a 370 cu in "C" motor)
Charles
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This, plus other info on the USFRA site, might help your insight also:
http://www.saltflats.com/traction.html
Enjoy- salt gets in your blood (other places too!)
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This, plus other info on the USFRA site, might help your insight also:
http://www.saltflats.com/traction.html
Enjoy- salt gets in your blood (other places too!)
I would agree that on an open wheeled vehicle and streamliners wide tires would be problematic. Open wheeled cars would have too much aero resistence and streamliner just don't have much room for them. As far as doorslammers are concerned this article is based on non fact based and is subjective. There are many fast cars that do use the "typical" skinny Bonneville tires, and that's fine for their cars. But why? You talk with many "experienced" racers about wide tires and the response you get from them is "your gonna kill yourself using those things". So why would any new racers want to buck the system and give the wider tires a try? The author above states "just look at the fast cars that run at bonneville and they use the skinny tire." How about Gale Banks, he used a wide tire in the late 80's and went pretty fast with them. We built our car with many of the designs that Banks used, including the wide tire. I think with doorslammers the combination of a non-suspended car and wide tires could be the determining factor for spin outs because of the wheel rate being too high. With our combination we have great traction, and if you listen to this author about fast cars just take his advice and look at the fast cars and their set ups and talk to the racers that are doing something different. You may or may not take their advice, just don't knock it until you try it or go faster. :cheers:
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Having been in the timing trailer and old timing stands since 1983 I have probably seen more spins then most people at the lakes and on the salt. The wide tires talked about in 90% of the spins are the wide oval type and most with treads and in short wheel base vehicles. Sports cars have the worst record with these tires. Any car can spin regardless of the tire. Narrow MT's and Good years nor are the Nascar Daytona's any exception.
A lot of spins are drivers trying to save it and over correct, others are steering ratios being to quick. Roadsters seem to spin a lot but it seems there are a lot more of them. The thing is the wide ovals has a softer side wall and tend to flex when side loading. I will probably get some argument's on this but having timed thousands of runs over the years one looks at a lot of things and only tries to point out some of the history.
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I'll go along with what Glen and Bvillercr say for sure. However I think cars spin because they lose traction- lots of power, not much traction. Especially short, rear weighted highpowered roadsters. I don't know what Dynoroom used on his bird but Gary Eaker had some sort of wide tire on his and went straight with near 300 times also. Am not sure the specific loading of a narrow one on the salt is better than a wider one or some other advantage, but mostly think the wide tire is an aerodynamic downside due to frontal area and yes, you won't see on a lakester-usually- depends on whats available and where being run. Not sure a magic answer. I posted the link more for the surface/traction info and thoughts than the tires per se, but I surely agree different strokes (tires) for different folks. Sort of like the locked rear arguement. If you spin with a locker, put an open rear in it. If you spin with an open rear, put a locker in it! :cheers:
Try it out, then go from there.
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We have more power than most and we don't have issues with tire spin in 3rd or high gear. I just wonder what kind of set up the cars that spun had? Rigid or suspended and how stiff if suspended. Looks like we have a good set up for our car. :-D
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And a lot of it is lack of seat time under the conditions of the salt. It's not a drag race and takes a soft foot as well.
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And a lot of it is lack of seat time under the conditions of the salt. It's not a drag race and takes a soft foot as well.
Ahhhh, does Mrs Boyd Coddington and associated fiascos ring a bell?
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And a lot of it is lack of seat time under the conditions of the salt. It's not a drag race and takes a soft foot as well.
Ahhhh, does Mrs Boyd Coddington and associated fiascos ring a bell?
:-D
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Wide tires work fine on pavement like Texas Mile, Maxton and Loring. Wide tires on salt can perform as though they are hydroplaning - even when the salt is perfectly dry. All those guys who tried them in the past provided enough "corporate knowledge" to suggest that the narrow tire is the only way to go on salt.
DickJ
In East Texas
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Wide tires work fine on pavement like Texas Mile, Maxton and Loring. Wide tires on salt can perform as though they are hydroplaning - even when the salt is perfectly dry. All those guys who tried them in the past provided enough "corporate knowledge" to suggest that the narrow tire is the only way to go on salt.
DickJ
In East Texas
really, so how does a car go 285 in the first timed mile if the tires are hydroplainning? :roll:
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Wide tires work fine on pavement like Texas Mile, Maxton and Loring. Wide tires on salt can perform as though they are hydroplaning - even when the salt is perfectly dry. All those guys who tried them in the past provided enough "corporate knowledge" to suggest that the narrow tire is the only way to go on salt.
DickJ
In East Texas
really, so how does a car go 285 in the first timed mile if the tires are hydroplainning? :roll:
DICK, I'm waiting for a response? Anyone want to take a crack at this?
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:-D Have you been working with the Propster?? :evil:
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:-D Have you been working with the Propster?? :evil:
are you speaking of Dick, Sparky?
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Dick is probably on the way to The Texas Mile.
Fred
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Naw man---I just KNEW you had to have some secret weapon to get them big ole fat tars down the course and I figured it must be you have them "on step" and are planing on down the course pushing them with a prop :-D ---- :evil:
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The difference is that I can back up my claims. :cheers:
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Yeah, but that spoils all the fun. :evil: :evil: :evil:
Pete
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I am not much of a pro, having only run one year, but narrow tires and a whole lot of lead is the way to go. I ran my 1990 ZR1 with 4.5 X 28 X 15 in the rear and about 2000# of lead with 640 Hp and it ran straight and true to 219 mph. tried removing 100# from the rear in an attempt to go faster earlier. And things got way loose once I was over 215, on the salt weight is definately your friend. Also one of the things I learned was that its still a drag race, and you need to hook up early if you want to get to 230 plus you better be going 215 by the 2.25 mark, as a whole lot of track goes under the car every second once your at speed.
my comment after my first run was man, 5 miles is short:)
Good Luck
Dave
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What kind of suspension are you using; stiff, soft, none?
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I am not much of a pro, having only run one year, but narrow tires and a whole lot of lead is the way to go. I ran my 1990 ZR1 with 4.5 X 28 X 15 in the rear and about 2000# of lead with 640 Hp and it ran straight and true to 219 mph. tried removing 100# from the rear in an attempt to go faster earlier. And things got way loose once I was over 215, on the salt weight is definately your friend. Also one of the things I learned was that its still a drag race, and you need to hook up early if you want to get to 230 plus you better be going 215 by the 2.25 mark, as a whole lot of track goes under the car every second once your at speed.
my comment after my first run was man, 5 miles is short:)
Good Luck
Dave
ABSOLUTELY...............it's funny but it's not til you're up against it that you really see it as a problem....from the outside it seems obvious but when you are going fast, the track goes away pretty quick...if you want to go fast you have to accelerate, the faster you go...the less time you have to do it, and ,er, then you have even less time, to go faster.....we were putting on 12 mph a mile, over the last three, no wheelspin , we could use a little more power :roll:
but I definitely agree...you need to be getting going EARLY in order to be going later
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Here is a data point;
152 inch wheelbase,solid rear, sprung front, modified roadster,weighs approx 3,500 lbs. 372 cu in blown on alcohol, has run as fast as 270 MPH.
We tried an experiment, back to back runs with 7.00-18 Firestone LSR tires and 8.00-15 Goodyear stock car specials. The Firestones were traditional narrow rock hard LSR tires, the Goodyears were standard bias ply stock car tires with about a 10 inch wide contact patch. Speeds were the same but the driver said the narrow tires were much easier to drive and the wide tires were "squirrely".
Jim in Palmdale
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It definitely is a drag race if we aren't going 245 in the quarter it's over. You just have to be able to accelerate with a little finesse.
Jim
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Here is a data point;
152 inch wheelbase,solid rear, sprung front, modified roadster,weighs approx 3,500 lbs. 372 cu in blown on alcohol, has run as fast as 270 MPH.
We tried an experiment, back to back runs with 7.00-18 Firestone LSR tires and 8.00-15 Goodyear stock car specials. The Firestones were traditional narrow rock hard LSR tires, the Goodyears were standard bias ply stock car tires with about a 10 inch wide contact patch. Speeds were the same but the driver said the narrow tires were much easier to drive and the wide tires were "squirrely".
Jim in Palmdale
I agree with you on open wheeled vehicles. Wide tires have too much aerodynamic down fall. For doorslammers it is completely different, so are set ups. :cheers:
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I am not much of a pro, having only run one year, but narrow tires and a whole lot of lead is the way to go. I ran my 1990 ZR1 with 4.5 X 28 X 15 in the rear and about 2000# of lead with 640 Hp and it ran straight and true to 219 mph. tried removing 100# from the rear in an attempt to go faster earlier. And things got way loose once I was over 215, on the salt weight is definately your friend. Also one of the things I learned was that its still a drag race, and you need to hook up early if you want to get to 230 plus you better be going 215 by the 2.25 mark, as a whole lot of track goes under the car every second once your at speed.
my comment after my first run was man, 5 miles is short:)
Good Luck
Dave
How was it with wide tires and a lot of lead or less lead?
JL222
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as to suspension, we were moderately stiff, with 52 % weight to the Rear. I thought about using a four link set up to get a better weight transfer, but that just works for the hole shot, and not what you want at speed. I had two problems last year, I could not get on the wood, untill I was long in second gear due to wheel spin, and once I hit 215 I was at the aerodynamic limit of the body and was getting several inch's of lift in the front, even with a lot of weight on the front. The Factory lift numbers for my vette are 440# of lift at 200 mph, so you can see how much this changes on a production car with just a small increase in speed.
What I can say is the car ran straight and true, like it was on rails untill I took some weight out of the car then the tires broke loose at top speed, I had to pull the chute to prevent a spin.
I have not tried the wide tires, but in 1990 when the zr1 came out it was run at bonneville, bone stock. According to the team, I was told it was horribly unstable at 180. Once again production body.
I believe, you will find once you vist Meca ( the flats) and see how, loose the first 1/8" is and how hard the surface is underneath, you will come to the concusion with the majority, that what you want is a small foot print with a lot of weight. But Hey go for it and good luck.
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as to suspension, we were moderately stiff, with 52 % weight to the Rear. I thought about using a four link set up to get a better weight transfer, but that just works for the hole shot, and not what you want at speed. I had two problems last year, I could not get on the wood, untill I was long in second gear due to wheel spin, and once I hit 215 I was at the aerodynamic limit of the body and was getting several inch's of lift in the front, even with a lot of weight on the front. The Factory lift numbers for my vette are 440# of lift at 200 mph, so you can see how much this changes on a production car with just a small increase in speed.
What I can say is the car ran straight and true, like it was on rails untill I took some weight out of the car then the tires broke loose at top speed, I had to pull the chute to prevent a spin.
I have not tried the wide tires, but in 1990 when the zr1 came out it was run at bonneville, bone stock. According to the team, I was told it was horribly unstable at 180. Once again production body.
I believe, you will find once you vist Meca ( the flats) and see how, loose the first 1/8" is and how hard the surface is underneath, you will come to the concusion with the majority, that what you want is a small foot print with a lot of weight. But Hey go for it and good luck.
Bruno....I just don't know where to start with this rediculous statement that you just made. :roll: I know your a rookie at bonneville so I will try to be easy on your ego. :-D Our car has been running at bonneville for over 20 years. We built the car for the purpose of this sport and modeled it very closely to Gale Banks firebird. Our car puts out four times the power that yours does. We run a four link, and Goodyear 2222's they are fatties. Last year we ran 268 in the 1/4 and 285 in the mile, so your trying to tell me that a small foot print is better. I'm not saying that skinnies are bad, and many have gone fast with them but only two maybe three doorslammers have ever gone faster than ours in that first mile. We also run a soft suspension set up and we launch pretty good even at the 1/8 mile. :roll: Maybe you should read our build diary (Getting ready for Bonneville) and check out our set up. :cheers:
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Thanks for not rubbing that in, Hey, I am alway willing to learn :-P, I checked out your build diary, hard to argue with your success. :-D Way cool car.
All the records in my class are set with skinnys, so maybe I should not be following the rest of the sheep. With a non Altered Body fighting lift at speed its hard to put the weight where I need it for launch, and still keep the front down. I will looking to a softer spring rate, that could be my ticket to impound.
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LOTS of Rake :?
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It definitely is a drag race if we aren't going 245 in the quarter it's over. You just have to be able to accelerate with a little finesse.
Jim
Yea Jim ...I consider it a drag race unless your middle mile speed is as fast as your last mile exit speed
JL222
If your last mile speed is as fast as your exit speed on second thought.