Landracing Forum
Tech Information => Technical Discussion => Topic started by: Sumner on December 21, 2004, 01:49:00 PM
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(http://purplesagetradingpost.com/sumner/hooley/hooley%20end%20long%20run.jpg)
We would like to hear some opinions from you car guys on Hooley's car that we ran last year. Due to oiling problems we only got to make four runs on the car, so Hooley (driver/owner/builder) didn't get a lot of seat time to really feel the car out.
He made three licensing passes of 127, 173 and 191. The first two passes he said were a piece of cake. On the 191 run he felt the car move aroung a little, but didn't really have to correct at all. On the second and 3rd passes we lost oil pressure at the end of the runs due to the fact we were pumping it all up top and it was returning fast enough. Hopefully we have that problem fixed for next year.
Because of the oiling problem we decided on the 4th run (on the long course) to just run through the 3rd mile and shut it off. He ran a 198 in the first 1/4 of the third mile and averaged 207.485 for the whole 3rd mile and I figure his exit speed was about 218-219. Again on this run the car hunted a little, but didn't really require any steering input to keep it straight. Hooley did say that something seemed a little strange in the back, maybe like it was getting a little light. The problem was he was at speed for such a short period of time and this was the first time he ever went this fast so a lot was going on for him to take it all in. If we wouldn't of had the oiling problem and could of run through the 4th and 5th miles I think we would know more.
First some facts. The car with driver scales at only 2800 lbs. (pretty close to 50/50)and we see so many people adding ballast to their cars and wonder if we should, or if we only should if we run into a problem?
The car didn't have a belly pan, but he is now installing one and almost done. We don't know if this could make matters worst, better, or stay the same.
He has ladder bars and coilovers in the back. We are adding chains to the rear axle to limit how much the body can lift before it also has to lift the axle. Good idea or bad idea? Our feeling is that the coilovers are pushing up on the body and providing assistance to the air, which might also be creating a lifting effect to the body.
(http://purplesagetradingpost.com/sumner/hooley/hooley-5.jpg)
I put this picture in to kind of give you an idea of the car and how it sits from the side view for comparison to the rake of the car in the next picture.
(http://purplesagetradingpost.com/sumner/hooley/hooley%20car%20at%20speed.jpg)
This is about the only picture we have of the car at speed except for some video that isn't that good. To me it looks like the car is lifting some in the rear in comparison to the picture before this one. We belive this picture was taken on the 2nd run and the car was running about 175 if that was the case. Also if that was the case we still had our big 28 inch tires on the front at that point and our small 24 inch tires on the back, which should have made the back lower yet.
(http://purplesagetradingpost.com/sumner/hooley/hooley-3.jpg)
Here is a picture of the back spoiler. We have it raised a little and it has some adjustment, but we really don't know what we are doing with it and what we should be looking for.
So even though the car ran fast and stable we hope to run in the 235 to 240 mph range next year and want to do everything we can to make the car as safe and stable as possible.
So any comments on ballast, chaining the rear, belly pan, rear spoiler and anything else you could help us with would be greatly appreciated.
You can read more about the runs and see more pictures to compare on the link below.
Thanks in advace for any help,
Sum
207 mph with Hooley (http://purplesagetradingpost.com/sumner/hooley/hooley-2004.html)
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Was the engine running all out or was there a lot of pedal left? With our car when we run out of HP the car gets that really light in the ass feeling and starts to drift. Just the first thing that came to mind.
Dallas
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Dallas he was running a stock 400 block and a cast crank so we were limiting it to 6500 and that was right at what he ran on the last run. It pulled right up to that and by then he was at the end of the 3rd mile and shut off, so the engine probably could have pulled more according to him, but probably would have broke. We did end up with a couple scuffed pistons.
The first time he noticed any hunting at all was on the 190 mph licensing run where he just ran up to 190 before the 3rd mile and just held it there through the whole mile. So this situation was a little like what you mentioned.
If the car keeps handling like it has then no problem. We are just trying to take preventive action with the hopes of running 20 mph faster.
He is getting an after market block and basically a whole new motor, so we won't be limited with the 6500 rpm limit.
Thanks for your thoughts,
Sum
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What is the front end settings? Camber, caster and toe? Does it have a locked or open rear end?? Have you rolled out the tires for the real size of each? Lots of things can make a car wormmy at 200 mph.
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Just a thought, not advice: looks like you're right - the rear is rising at speed. Eventually the rear suspension unloads the tires. Result: oversteer.
Without going into wing design and placement, you need more angle of attack, even 5 degrees may feel different. If you use too much, the car will be more stable but slower (duh), hopefully before the wing stalls. If you run out of angle adjustment (and still getting improvements), adding length will help some, also an "indy angle iron" can be added to the top surface (only) of the wing rear edge, about 1/4" to 3/8" high. Aluminum "L" shaped extrusion is fine.
The video would be easier to vet if you took a frame capture and used Photoshop etc. to super-impose that frame on a re-scaled pic of the car at rest to see exactly what angle you're getting (there might be some rise in the front as well, perhaps air is geting under the car).
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Thanks guys for your input. It is what we need.
I sent Hooley an e-mail and will try to find out what he did on the alignment. I know we didn't measure the tires to check their roll out with each other.
The rearend is a ford 9 inch with a full splool.
panic thanks for the input on the rear wing. We have never done this before, so Hooley just built one that "looks" right and we set it where it "looks" good and went for it.
I don't think I have any software on my computer that will let me capture the video like you said and our video from outside the car of it going down course isn't that good, but it sounds like a good idea.
For next year we were going to put some rods on the car with markers on them to see what is happening with the suspension travel.
Also like I mentioned he is finishing up now on a belly pan, but we have no ideas as to the effect it will have on the car.
We are also going to clean up the nose a little and smooth out the fake grill openings at the bottom of the front and make the fronts of the headlights more tear shaped.
Guys we sure do appreciate the input so far and would really like to get all that we can as a lot of you have been running cars over 200 for a lot of years and I'm sure you have a lot of knowledge as to the good and bad things that can happen at those speeds.
c ya, Sum
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You make no mention of the spring rates but if it were me I would start with whatever is the corner weight of the car. IE if the front weight is 800 lbs on each wheel I would use that. if they are slightly different I would average them, a 775 on one side and a 825 on the other is an 800. same for the rear the whole idea is to limit the chassis to around 1/4 inch or less of movement total. Second the angle of attack at speed looks much more realistic that the one sitting still. the aero loss from angle of attack is minor compared to tipping the spoiler/air brake up to gain downforce. Nose up ass down is a bad place to start it looks like a very nice lifting body in the side view standing still. Lastly any chassis is more stable with a g input either positive or negative. if you drone along at zero g input to the chassis it is going to get very 'busy' as it has no way to plant the tires in any direction. Droop limiters are not a bad idea at either end. Chain or cable straps just make sure is something that won't snag anything or hang down below the car at any chassis attitude.
Dave
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One more thought. When you put the belly pan on I would get the nose as close to the ground as practical,possibly testing spring rates first, and use approximately 3 degrees on the belly pan with the rear higher than the front.
Dave
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If you can't find anyplace on the car to test that's out of the airstream, the first place to measure is from the rear wheel cover center to the lower edge of the fender. A small dot of sharp color (red or black) in the exact center of the cap will make it stand out in a pic, and a short section of tape with alternate black and white bands 1" apart (smaller is more accurate but may not be visible) on the front and rear of the wheel opening will give you a reference. Easy to draw a line through the center horizontally and pick up which band it catches at speeds. Even if the tape isn't vertical, try to make the bands vertical so you can actually measure it from a pic.
Many software programs out there that will do a frame capture from a video, someone can do it for you. For best effect (no parallax, minimal perspective) camera height should be as close to wheel center as poss and 90 degrees to the car as it passes.
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Here is one more thing to look at after you have done all of the above. At speeds above 200 you don't have to move the steering wheel much to affect the car. Even a subconcious twinge will misdirect the car. When I was building my car eight years ago, I was told by several Bonneville veterans to use the slowest steering ratio I could obtain. I wanted to use a rack and pinion steering, so this presented a dilemna. After much research I found that Roundyround cars use these cute little devices called Steering Increasers to speed up there steering ratios on short tracks. As I looked at the picture in the catalog, I turned the page upside down, and PRESTO!, I was looking at a Steering Decreaser! I installed a 1.5 to 1 Increaser upside down below the steering wheel and now have a 66% steering ratio, which has slowed the steering ratio by a full third. This has in effect taken some of the ability to "over drive" the car avay. There are now several cars running them and I know that Terry Hunt swears by his. I have never run my car without it, but I have to believe it helps. Bob
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Thanks for all the respondes guys we really appreciate the input. Bob I've had some people mention to me about slowing the steering down as much as possible also and think it is a good idea.
I'm still wondering what course of events leads to adding weight to the car. Seems like a lot of cars have added a lot of weight and are almost twice as heavy as Hooley's.
I'm still trying to get some more facts to some of the questions you have raised and will post them when I get them or Hooley will post them.
Thanks again,
Sum
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Sum, I don't claim to be a expert, but the rule of thumb I use is: don't add ballast unless the car is spinning the tires or trying to take flight. Also, keep the ballast between the axles and as low as possible or you may end up with one fast pendulum.
Bob
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IFATGMC,
Just another couple of things to consider with the "Stude". I would suggest that you put the car on scales on each wheel and make sure that the weight on each wheel on each side is as close to the same as possible. I also agree with Dave that you should run some really "stout" springs with wheel rates in the same area as the weight that the wheel is carrying.
From the pictures it does appear that the back end may be lifting which would probably mean that you need to run the car with more forward rake, as it is the air going over the top of the car that is at a higher speed and therefore lower pressure than the air below and is lifting it. Your belly pan needs to be pretty stiff if you are looking for some sort of gound effect down force from it. When I was doing sports cars back about 20 years ago we had some of the first Lola T600s and they were some of the first "ground effects" cars and our "belly pan" which had the ground effects tunnels in it and extended from the front of the car to the rear was made from Kevlar skins on a 3/4 inch honeycomb core and it was connected to the car with at least 30 fasteners and you could support the thing on each end and stand in the middle and it would not deflect! So make it stiff. You may even consider some sort of side skirt which is legal in your class.Good luck at going 250 and see you a Bonneville in August!
Rex
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I would suggest that you put the car on scales on each wheel and make sure that the weight on each wheel on each side is as close to the same as possible. I also agree with Dave that you should run some really "stout" springs with wheel rates in the same area as the weight that the wheel is carrying.
He has scaled it since last summer and I think the total weight was about 2800 with him in it and almost right on 50/50 front to rear and side to side. The springs he is using are really stiff and offer very little in the compression mode. I belive they are stiff as they weren't the right ones for the coil overs and he has the coil overs cranked way down. I wonder if they are trying to work with the aero lift and are pushing the car up. He will have axle limiters on the car for next year.
The pan is out of some pretty stiff aluminum and is attached to the frame rails and crossmembers, so I don't think it has much give, but I'll check with him on that.
Thanks for the suggestions,
Sum
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The thing about ballast is you have to be prepared, in advance, to add or subtract as necessary. Remember: as long as you have traction the lighter car will always be faster.
Same applies to making rear spoilers adjustable. May take several runs to get it where the driver is happy, but seat time is a good thing.
John
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Thanks John, and that is a good point about being ready to add weight to the car before we get there if it is necessary. We will look into doing that.
c ya, Sum
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Maybe only tangentially related, but would it help to use a shock setting with a fairly soft compression stroke and a stiffer rebound, sort of the opposite to how the front end is set up on a drag car, to keep the shocks from raising the car?
<small>[ January 12, 2005, 04:09 PM: Message edited by: StraightSix ]</small>
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Six, My theory is to run very stiff springs AND shocks. If and when you hit a bump out there, the last thing you want is to have the body lift and allow more air under it...at least with a full bodied car. For example, I am running 400# springs on the rear of my 53 Stude coupe with 500# of ballast in front of the rear end.
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Six, I forgot to add, I run short 550# coil overs on the front with a air dam to keep the front end loaded..Bob
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OK makes sense but how does your compression damping compare with your rebound damping?
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Bob that is all good information. Do you have a picture of your stude on the internet somewhere as I'd like to see it (I probably have in person, but don't know which one it is)?
Did you run this last year?
Did you ever run without the 500# of weight?
If so what happened that lead you to adding the weight?
A lot of questions!!!!
Thanks, Sum
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Sum, My car is #394, Old Stud Racing. It is painted "Moon" yellow with red lettering. If you want to see my "famous" low speed spin, go to www.speednchrome.com, (http://www.speednchrome.com,) click the videos, and when you get to the page with two rows of boxes, scroll down to the third one in the left collumn and hit download. I have always run at least 300# in front of the rear axle, my reasoning being trying to tame the torque down a little as I go through the first mile. I am running a 435 cu in Early Olds on fuel, and this puppy puts out over 700lb. ft of torque at 3500 rpm, and if you watch the video, you will understand. As far as rebound, I run my car like a brick. I have sway bars on both ends, and there is little if any rebound in the suspension. The last six passes have been over 200, and it drives like a dream. The best thing I did, was to add the front Valance/Spoiler two years ago. Keeping the air out from under the car makes a hell of a difference from about l75 up. Bob
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Sorry, but I posted before I was done again. The car is a 53 Studebaker running in B/CFALT. The other reason I have always run the lead is I wanted to run aproximately 55% of my total weight on the rear tires, so with that big stump puller in the front, I needed it. My car weighs 4500 lbs with fuel and driver. Incedently, Lionel Pitts told me that to make the McDonald and Pitts Firebird handle above 250, They poured the frame full of lead, and it now weighs 6500 lbs, and ran 297 at the World Finals .
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One more word on "spring rebound". If you have the missfortune to get sideways at say 200mph, you are not going to want to have a suspension with very much travel, or I believe, you will soon look like a turtle on its back. Remember, the goal here is to keep the rubber side down.
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We have added close to 2000 lbs of lead in the last 3 years, this is the only year the coupe didn't do circles since adding the big engine. Just poking around and asking questions it seems a lot of the faster door cars are running close to 20 lbs per mph. This isn't absoulte of course just what my limited research has come up. With 5 miles of track the weight isnt that big of an issue.
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Thanks for that additional information Bob. We are going to make provisions to add weight if needed at b'ville. We will make secure mounting fixtures and take weight with us. So far up close to 220 it has handled well. We had probably about 600 hp and 600 lb/ft torque with the motor last year, but hope to add about 150-200 hp with a blower this year, so things could change and we hope to be ready for them. The Speed & Chrome site is down right now, so I'll have to wait a few days to look at the video. I found your car in last years program. Very nice looking car and I like the way you handled the hood.
(http://purplesagetradingpost.com/sumner/temp-pictures/394%20Stude.jpg)
If you don't have a picture of your car on the internet (you do now) I could post one for you on my site and then if you wanted to show it to someone you could give them the link and they could see it like the one above of your car. If you could get me a better colored one I'd post it.
Thowey what coupe are you running (number)? Thanks for that information also about the weight. It is the kind of information we are looking for since we only ran last year and then only 4 runs.
c ya, Sum
207 mph with Hooley (http://purplesagetradingpost.com/sumner/hooley/hooley-2004.html)
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IM NOT SURE. BUT WITH 55% OF THE CARS WEIGHT ON THE REAR WHEELS THIS WILL HELP TO SPIN THE CAR. A DART IS HEAVY IN THE FRONT WE HAVE ABOUT 52 TO 55% OF OUR CAR WEIGHT ON FRONT WHEELS AND THE CAR RUNS GREAT. BAKERSFIELD BOYS #1661 34 FORD COUPE
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Phord, a fenderless coupe does not have the frontal area or downforce that a full bodied sedan has, so the weight bias is different.
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How many darts are powered by the rear feathers?
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Sum, the SpeednChrome website is back up if you want to see my "famous" low speed spin. Click videos, then scroll down the Bonnevelle items to Studebaker. This is what happens when you add 25% nitro, have a spool rear end, a lot of low end torque, slow reflex's, and have been sitting in the car too damn long...........Bob
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I saw it. Now what am I going to say that would be appropriate and not get me into trouble :) .
I'll probably do the same thing in a year or so. Once I was leading a motorcycle race by a good bit and coming to the checkers I came out of a dip and decided to show off a little and wheelie across the finish line. Well the bike came up further than planned I came off but still held on to the handle bars and got it down and across the finish line running along side of it. Quite embarassing :( .
Well anyway glad you shared that with us and you can see that once the rear got loose the spool really hurt you.
c ya, Sum
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A couple of things you might consider with a Stude. The body is basically an airfoil, they have been known to suck out the rear window. You can duct air from underneath and dump it out at the base of the rear window on each side. Second, you might make up two struts the same length as your shocks (at rest), remove the shocks, install the struts for an unsprung setup. This keeps the body from swaying on those buggy springs at high speed. Try it, you'll like it. Good luck for a stable ride.
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I'm Bob Ragsdale (#745 CBGAlt.) I run a 53 Stude. that weights in approx. 2800 lbs dry. I have added enough weight with water, oil, fuel, ballist plus driver to gross approx. 4,000 lbs. I have equal weight approx. 1,000 lbs on all four corners. This setup has put me in the 2 club as well as top speed of 230+. It goes straight, handles as well as could be expected. No spin outs with this setup. Hope this helps you.
Bob
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The only comment I have to add is what Mike Cook told me about Ballast with the Modified sports car Vs the Camaro... it worked so it has merit..
That is that every car is a bit different and each requires it's own set of parameters for Ballast....
You start running ballast as soon as you need it... in other words when the tires start spinning you start adding ballast... where you add it depends on the car.
My Camaro loves the 50/50 situation where the Berkeley runs 65% on the rear wheels...
I guess if you have the ballast provisions and time to test it all out you can come up with the right set up for your car... just remember not all studes are built the same...
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Hi Ken, Bob and Keith. We just wanted to thank you guys for the input and let you know we are reading it. Hooley has added some attachment spots for ballast and we will take some this year and use it if the need arises.
Bob I guess Hooley isn't too far from you in OK. He is up in Chelsea.
Thanks again for all of you who have contibuted to this post.
c ya, Sum
Finally Lakester Construction Has
Begun (http://purplesagetradingpost.com/sumner/bvillecar/bvillecarindexpage.html)