roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Race car suspension set-up, sideways.
Nascar is always counter clockwise on ovals and mostly clockwise on road courses ? Everybody else seems to be "mostly" clockwise on road courses ? Seems like you would weight jack the car, to favor direction car spends most time on a given course ? For instance, car spends 80% of lap time clockwise, would you not weight-jack the car to compliment this. Yes the car would be somewhat slower,(20%) of the time while faster for 80% ? I remember the GTP cars at Riverside, went to great pains, making sure theirs cars had zero off-set weight, with driver onboard. This course was at least 70% clockwise. I wonder. Onward, roverman.
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Moderator Curtis Jacobson Portland Oregon (4576 posts) Registered: 10/12/2007 02:16AM Main British Car: 71 MGBGT, Buick 215 |
Re: Race car suspension set-up, sideways.
Some roadracers do use asymmetrical set-ups. That might include spring adjustments, tire pressure adjustments, or shifting of actual mass (e.g. ballast on cars that have to carry it). MGB GT V8 racer Jerry Richards told me he does.
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Bill Young Bill Young Kansas City, MO (1337 posts) Registered: 10/23/2007 09:23AM Main British Car: '73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep |
Re: Race car suspension set-up, sideways.
We've considered ballasting the RV8 to favor either leff or right side depending on the track if necessary. My take is that for a road car it would depend on the particular track and the "worst" turn for the car on that track, might be a left or a right, but gaining a few hundredths or a mph or so might make a significant difference in lap times. You'd almost have to have a recording system with various inputs to tell where the benefit might be best though.
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roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Race car suspension set-up, sideways.
I don't know how many LBC's are underweight for their class-but maybe move existing things like battery, fuel cell,(driver/extreme) ? Obviously, it's easy to jack weight with anti-roll bars, coilover shocks, or coil shims. I would consider more camber(outside), to favor predominent turns. When we look at Nascars,(oval), we see both front tires lean into turn, ie. inside has positive camber. Adequate positive caster should help the inside tire, for road courses.. Onward, roverman.
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Bill Young Bill Young Kansas City, MO (1337 posts) Registered: 10/23/2007 09:23AM Main British Car: '73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep |
Re: Race car suspension set-up, sideways.
Makes sense Art, but so many variables that my mind boggles at the very idea of trying to do much with the alignment. Even tire stagger and pressure can be taken into account for turn predominance. From watching so many good SCCA racers over the years it appears that just setting the car up pretty neutral right and left is the way most go. Some play with front to rear weight bias a bit to get more traction out of the turns, but still I think most don't get much more than 5% out of balance even for that purpose. The Rv8 wasn't built all that light, yet still wound uip almost 200 pounds under weight even after our weight allowances for transmission type and wheel size were taken into account. We added lead ballast to get as close to even side to side, corner to corner balance with about a 55% to 45% bias rear to front. The car tends to understeer just a bit so we might move just a bit of weight back towards the front if some tire pressure adjustments don't help.
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roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Race car suspension set-up, sideways.
Bill, Have you tried "lighter" on the front anti-roll bar ? Lower the front roll center ? Tire temps ? Nitrogen int he tires ? Cheers, roverman.
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Phillip G Phillip Leonard Kansas City (395 posts) Registered: 02/03/2008 04:12PM Main British Car: 1992 MG RV8 Rover 3.5 |
Re: Race car suspension set-up, sideways.
Guys,
Short of tire pressure changes, or maybe shock absorber setting changes ..... ... over the course of a 4 or 5 or even a 6 race season, it seems to me that only ONE major change can be made to the race car at a time ... if it is a significant change.. And that one change, practically, can only be accomplished over the prep time between race weekends. Otherwise, how do you know the outcome or result of the change from the previous race weekend. Several changes. of course, leave you guessing which one caused the affect. Oh to be a full time racer with full time mechanics and multi testing sessions - so much might be accomplished. So goes the plight of the amateur racer keep them on the track, phillip g |
DiDueColpi Fred Key West coast - Canada (1365 posts) Registered: 05/14/2010 03:06AM Main British Car: I really thought that I'd be an action figure by now! |
Re: Race car suspension set-up, sideways.
Stay the course Phillip. Your going in the right direction ( Pun intended )
Way too many racers take the shotgun approach to setting up their car. They get so many changes going on at once that there is no way to tell what worked. One "documented" change at a time will get you there. The notes are important, a bad change at on track might be just what the doctor ordered for another. Gas or brake, one pedal on the floor at all times. Cheers Fred |
Bill Young Bill Young Kansas City, MO (1337 posts) Registered: 10/23/2007 09:23AM Main British Car: '73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep |
Re: Race car suspension set-up, sideways.
Thanks Fred, that's the approach we're trying to take, one step at a time with good documentation and driver's notes for feedback. We still have some instruments to aquire that would help collect data as well. All in good time.
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roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Race car suspension set-up, sideways.
GT-2, what to do ? Since this is SCCA, you might ask your fellow competitors...and then do the opposite ? Good Luck, roverman.
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Re: Race car suspension set-up, sideways.
The TR8 has such a short wheelbase that you are going to find that the car will be sideways on just about every corner except for long sweepers. The old modo of slow down to go fast isn't as true in a TR8 as it is in other longer wheelbase cars. You spend a lot of time throwing the car into corners and then counter steering with the wheel and driving out with the throttle. In order to have the most control of the car, corner weights are essential. Matching front to back and side to side is nice, but matching corner weights is critical. Trying to drive a car that is on the edge of control is very difficult if the car wants to teeter totter back and forth. On my ITS TR8, all of my weights were within 15 pounds or so of each other. If a track was predominantly turning in a certain direction, I'd try to lower that side a little more than the other, but you have to remember there are minimum rocker panel height requirements. What good does it do to raise one side if they are both already down close to the limit. Learning to drive a race car with a short wheelbase and lots of torque takes some getting use to. Once your comfortable thou, it's an absolute blast. Winning and losing seems a lot less important than just going out there sliding the car around and having a great time. Racing in one of those momentum or slow down to go fast cars will provide you with one or two of those edge of control moments where your stomach is in your throat and you have to take a deep breathe afterwards. The TR8 is one after another after another on the race track, so be ready for it.
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roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Race car suspension set-up, sideways like a TR 8
" Ok Art, we're going to strap you in this Rocket Sled...be ready for it"! SOFM, 35 years ago, SCCA drivers school at RIRW., It was like stepping out of VW bug and being dropped in a F-18 fighter jet, into the middle of a dog fight ! This was not boring ! I miss it. Got to get back in it. Cheers, roverman.
Edited 1 time(s). Last edit at 05/18/2012 01:41PM by roverman. |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: Race car suspension set-up, sideways.
Stiffer springs on major outside of turns use ? This could meet the minimum static height, but rate would stack quicker. Cheers, roverman.
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