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I have a question on weight placement. On some of the heavier objects mounted, if given a choice, is it beneficial to mount them closer to the COG at a higher height, or further away at a lower installed height?
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That's a good question. It depends on "how far" we're talking. Meaning, if we have the choice of mounting 30# battery 10" above the bottom of the chassis behind the passenger seat ... or ... 3" above the bottom of the chassis but 20" behind the rear axle ... for sure we'd go with the first option. On the other hand, if we had the choice to mount our 160# fuel cell 20" above the above the bottom of the chassis behind the roll cage ... or ... 1" above the bottom of the chassis but 10" behind the rear axle ... for sure we'd go with the latter option. So if definitely depends on "how much" up or away from the COG we're considering. I try to keep all the mass possible inside the wheelbase. As things past either axle centerline add to the pendulum effect. The realities of packaging occasionally prevent that and we end up with the fuel tank behind the rear axle & the engine & radiator ahead of the axle. I suggest you do your best, but it's not always practical to make these cars perfect. |
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Not what you told me when I was ordering !!! ++++++++++ Kidding folks ++++++++++ |
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Ron, did not know you were working with Ron Ver Mulm on his Camaro. I've known and watched him for years as he was "close by". That car is special for sure and I'm betting it's even better now. |
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I think I told you the car would be perfect ... for hauling azz. :) |
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Yeah, he emailed me the link to the video to watch after his first day out with it. He said it has WAY more rear grip on entry & exit, which is exactly what a decoupled 3-link does. The accel side of his is spot on. The decel side needs stiffer dampening & spring rate. I do not know how much he picked up, but he said it was quicker than ever. |
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I see the upper link is offset inboard of the differential (which itself is offset well to the right), but the upper link still appears to be offset to the right (passenger side) of the center of the axle housing. How did you calculate the left/right lateral offset of the upper link with this oddball configuration? Thanks Pappy |
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Hey Pappy ! The pinion offset (or 3rd member offset) does not play a calculation in the determination of top link offset. The track width & friction (or power loss) from the specifics of the rear end are used to calculate the optimum top link offset. While I don't share my formula, I will say the more power loss a specific rear end creates, the more it is unevenly loading the left rear tire & the more we're going to move top link to the passenger side to neutralize this. For folks that don't know this, all symmetrical rear suspensions experience "torque steer" ... meaning the left rear tire gets loaded more than the right rear tire. The amount (or degree) is directly related to how much friction a given rear end has, from it's hub bearings, carrier & pinion bearings & R&P gear teeth meshing. |
I have a question on the steering shaft. I looked at the Sweet and Woodward universal joints, and they state to keep them under 20*. It looks like your angle after the firewall kicks over at about 45*. Is it okay to run that much angle? I’m going to be close to the same angle and thought I would need a double to half the angles, but if they can run that much, would make life easier.
http://i1060.photobucket.com/albums/...sae2pju7b.jpeg |
Weld/sutton track car
Ron,
I understand the decoupled 3 link... is that why you did not do an IRS rearend? Or too many things to break or worry about with halfshafts, etc Bob |
I'm curious about this too Ron.
I've always thought IRS was a good concept on paper but torque limited in reality. This was my own personal opinion after reading a few things, but I could be completely off base. |
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That photo angle is a little deceiving. The angle difference is about 32° & we've never had a problem with that. |
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Hey Guys ! As you know, just about everything has pros & cons. There is no perfect anything, let alone a rear suspension. Some are better than others in a specific situation. I've designed & raced a lot of cars with & without IRS. Some factors that guide my designs & builds are: A. IRS does NOT add more rear grip. If it is setup optimum ... as opposed to "Hey! It fits! Let's just weld it in here" ... we can get the roll center optimum, rear steer either positive, neutral or negative, toe in or out ... to HELP/Assist the car to turn better. B. Some cons are the roll center is NOT quick & easy to tune, getting the geometry optimum is just as complex as front suspensions & if you change the ride height, the geometry goes wacky. Overall they add weight to a car. They cost more & have durability issues to overcome. C. If I'm designing & building a rear engine car, an IRS is practically mandatory. If the car is going to be LOW ... like 1/4" to 1" off the ground ... and the front end can not travel very far (due to the low ride height) ... we can't get very much "pitch angle" under braking. This limits how much weight transfer we'll get to the front tires, so having IRS really helps us to get this car to turn better. If I'm designing & building a rear engine car with a 1/4" to 1" ride height ... I WANT an IRS to help the car turn better. Regardless of cost or complexity, the IRS will be best in these applications, like Formula cars, Indy Cars, Prototypes, etc. D. If someone has their car at some kind or "normal" ride height like 2.5" to 6" ... but run the front springs super stiff where there is very little front end travel in dive under braking ... we are not getting very much "pitch angle". So for them, they would benefit from IRS helping their car to turn better. E. If I'm designing & building a front engine car, IRS is not mandatory, just an option. If the car is going to have some kind or "normal" ride height like 2.5" to 6" ... and we can travel the front end anywhere from 2.5" to 4"+ ... we'll achieve a good degree of pitch loading the front tires. So the IRS is not an advantage here, at least performance wise. On rough streets & highways, IRS can offer superior ride quality. But we're talking about running race tracks here, which are vastly smoother than rough streets & highways. F. So if we're designing & building a front engine car of 2.5" to 6" ride height with a 2.5" to 4"+ front end travel strategy .. IRS is not a performance advantage ... so the question is which straight axle suspension is best. G. Truck arms & leaf springs are the low end have many "cons." 4-Links are OK, as long as they don't bind in the articulation range we need. Triangulated 4-Links need to have the top links go from outside onth ehosuing to inside on the chassis ... or the roll center is too high. IMHO torque arms are the best suspension is someone is keeping their back seat. But in track cars, race cars & Pro-Touring cars that want to perform at the top level, nothing beats a 3-Link. Just gotta run a roll bar/cage & eliminate the back seat to do it right. H. The basic 3 link articulates a ton & can have a quick & easy top link adjuster. If we offset the top link the correct distance, we can neutralize & eliminate torque steer. If we can place the top link mount high enough on th e housing, we can increase the percentage of torque that transfers load to the tires. And lastly, if we decouple it, we achieve something that NO OTHER rear suspension can. We separate the corner entry tuning from the corner exit tuning. With ALL other suspensions, the anti-squat percentage defines the rear tire grip on corner entry & exit. * Higher A/S % = More rear grip on exit / Less on entry. * Lower A/S % = Less rear grip on exit / More on entry. It's always a compromise. A decoupled 3-link is the best Racing rear suspension for front engine cars with 2.5"-6" ride heights .. because the corner exit grip is tuned independently with the "Accel Link" (the lower one) and the corner entry grip is tuned independently with the "Decel Link" (the upper one). There are cons to this style of suspension too. I. Regardless of type of link rear suspension, the other decision is Watt's link or Panhard bar. Since I'm a constant fine tuner, I like panhard bars that are fine tunable on both sides. For my clients, the Watt's links work best, because they're automatically neutral. And with our version, VERY quick & easy to adjust. Literally 20-30 seconds. Hope that sheds some light on when & why IRS is better or a straight axle with some form of link suspension better suits the application. |
Ron and I have had many discussions regarding the attributes/weaknesses of the IRS. I think I have finally discovered an IRS that addresses a lot of the issues that Ron points out. In order to not hijack Greg's threat, I have posted a response in my projects thread "Old Track Car Project - New Update" for those interested in an IRS discussion.
Pappy |
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LOL |
Its true Greg, I got a meatloaf recipe a couple pages back. Their is also a cure for toenail fungus in the first couple pages, this thread is multifaceted, and awesome!!!!
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Come home when you can fold a paper crane...... How much does it cost to buy a crane in Shanghai?? Can you get a model to display in your office?? |
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Weld/Sutton track car
Ron,
As always thanks for the data We in our Pantera world have been debating spicer/u-joints vs CV shafts... one of my Pantera buddies states the harmonics are better with the CV joints.. others say they are not strong enough and require more servicing.. not sure if it is worth the cost Bob |
Ron Sutton Total Car Building Workshop in Columbus - 2 WEEKS AWAY!
The Ron Sutton Total Car Building Workshop in Columbus is ONLY 2 WEEKS away.
Tickets available HERE: http://shop.ronsuttonracetechnology....pping/?ic=6106 This workshop covers the Entire Car Build ... not just suspension. I'm going to show you how to build winning cars that work awesome from bumper to bumper ... car body, brakes, engine, trans, diff, aero & much more will be covered. More details in attached brochure pages. http://www.pro-touring.com/attachmen...8&d=1529424428 http://www.pro-touring.com/attachmen...9&d=1529424440 http://www.pro-touring.com/attachmen...0&d=1529424450 http://www.pro-touring.com/attachmen...1&d=1529424467 For more information about the Workshops, contact Susan Kinnicutt [email protected] |
Looking forward to seeing pictures of the BOSS on track tomorrow...or at least at the track.
Have fun!:thumbsup::flag2: ps, don’t suck |
WOW, if a guy doesn't read this everyday he misses allot...
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I think I just heard a gnarly LS Mustang go down the front straight.... I am 100 miles away mind you. :)
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Picture: Choking on sandwich while trying the wrangle the concept of Dan in an office . . . Nice crane!
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Gentleman......................................... ... Start................ your........................Engine!!
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Update
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I'm still on the road -- so quicky update.
Car is beyond awesome! SO WIDE and SO LOW...... and SO MEAN!!! We developed a minor oil leak late in the day so that killed the late day bonzai runs for real tire temps and wing changes etc. We will run the car again in "white" at NASA in August for more data and some beginning lap times. Having not done a test and tune day with a road race car --- it's pretty dang fun but also pretty technical! Ron has an "order" to things that he wants done and so was in constant communications with the pro - Benny Moon - who was the lucky bastard that got the seat time..... Getting everything up to temp -- bedding brakes -- and making sure things are tight -- and the computers all talking and making the changes to them for the screens "I" want to see.... Benny says "blows the tires off" -- "think of the throttle in this as a rheostat NOT an on / off switch!". "BUT MAN CAN THIS SOB TURN!" A late day unfixable trackside leak killed the end of day rock and roll runs --- so next up is August "in white" for seriousness!! LOL Oh Man wait until you see this thing rolling down track. Just Oh Man is about all I can say. Thanks to Ron Sutton and Randy Chastain (One-off Customs) and they're crew!! Greg Wall (AKA Boris or TOG -- The other Greg) - Dylan - Benny Moon - Susan Chastain -- MY LOVERLY WIFE who has gone above and beyond driving trucks and serving people and just on and on..... and My buddy Rob Dickey (FETorino) for flying in last minute to help with chauffeuring "Miss Daisy" around when I got too pooped....... Attachment 66059 Attachment 66060 |
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Greg had a great post.
I always like to give a "Good, Bad & Ugly" of our Race days, Tests & Initial Shake Down Day like this was: The Good: The car was a rocket. Engine ran great & fast. Car had great grip & turned like a champ. Brakes worked excellent. The little things worked well except 2. :trophy-1302: The bad: We had a couple oil spray issues. One from a valve cover & one from the dry sump vent. Easy fixes. Our 16 volt battery died & wouldn't take a charge. Obviously an easy fix to replace. :mad: The ugly: Aside from cleaning some oil off the firewall, having to jump start the car had me frustrated. :hairpullout: We'll fix those two glitches learned from our Shake down & have the car ready go go soon. Here are some photos: |
Looks awesome. I assume some big mirror is planned cause that is going to be a blind SOB.
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Gotta shake out the bugs. Looks good. Can't wait to see this thing run.
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Weld/Sutton Track Warrior
Very very cool
A little heavier than I thought.. did Greg gain some weight? Looks like the Wing is mounted high enough that a rear view mirror and a curved mirror will work for seeing things out back and to the side That is what dictated the height of mine.. I guess Ron and the Boys copied me glad I could help out:) Bob |
Knowing that this car is wider than stock, I can say that man that spoiler is HUGE! It literally looks like it dwarfs the car in a couple of the pics!!!
Congrats on hitting the track. Look forward to hearing Weld's own driving impressions. :) |
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Haha. :lol: The rear view mirror is 17" wide ! |
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Greg did "try" to chase the new car in his old car. But with Benny driving it at 70% it still distanced itself right away. Greg will drive it soon ! |
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Hells Yes!
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