MonteCarloSS.com
MonteCarloSS.com

CELEBRATING 20 YEARS!

Previous Thread
Next Thread
Print Thread
Page 2 of 3 1 2 3
#1071655 - 08/17/21 12:11 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
Direct personal experience...

I have felt many times over the exact ill that Bob now feels with his car when on course, and more importantly I have felt exactly how a much stiffer front bar corrected that ill.


Lance
1985 Monte Carlo SS Street Car
#1071658 - 08/17/21 06:36 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Jan 2000
Posts: 5,421
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 5,421
Pottstown, Pa
Mark, apologize for not responding. Have been to caught up in the current issues with A/C and cooling system plus the other life events to have time to think about the front bar.
But one thing is do understand is how Lance with a 1000 autox runs under his belt has a pretty good idea what works to make these cars better. Not saying his parts choices are the only choices just that he has run a lot of combos looking for the best for the old turd. And his car is very competitive with other Cam T cars. If looking at that class of cars dominated by old live axle rear suspensions iron huge front bars seem to be one of the ways to make them much better in the autox.
Not saying they are better when used for street duty, just they do seem to make a difference on track.

Being I'm running out of time as a competitive driver, 7th decade is underway, and actually events to run what ya brung for testing being less it's hard to evaluate your setup. So you take suggestions, see if they are a viable choice and make a decision if you want to go that route.

I can say what I've heard time and time again, tires, tires, tires, make the biggest improvements. The RT660 Falkens are noticeably a big improvement.

Oh, bought a front spring for the yard cart at the local hardware store. Cut it in half and get two new springs, same OD, same wire size, correct length, $3. 89 well spent. Ride and handling much better without a floating spindle.
Bob

#1071660 - 08/17/21 07:50 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
Lance - Got it. And I'm not even slightly disputing that. What I am questioning is whether that's the best, or only, solution to the problem.

I can't even begin to count the number of times in an engineering setting where people jumped to conclusions and fell into the trap of OFAT (One Factor At a TIme) thinking about solving problems. Questioning concepts down to first principles yielded better results, along with multiple-factor thinking, as embodied by the philosophy of DOEs (Shawn, if you're reading, I'm sure you're getting this.) But you folks aren't engineers - I get that too.

So, Bob, I'm pretty sure a stiffer front bar will get you better results. If that's enough to float your boat, and yes I do understand the pressure of time at this stage of life, then I genuinely wish you the best with that.

Best,
MAP


Last edited by MAP; 08/17/21 08:28 PM.
#1071663 - 08/17/21 08:45 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Apr 2011
Posts: 1,187
Hunter79764 Offline
10+ Year
Hunter79764  Offline
10+ Year
Member

Joined: Apr 2011
Posts: 1,187
Grand Prairie, Tx
There's definitely something to be said for taking a systemic/holistic approach for design, but there's also a lot to be said for optimizing a system based on correcting the biggest offender and picking off the lowest hanging fruit at each step, wherever you are in the process. More like Continuous Improvement vs R&D.
I'd love to have the budget for R&D efforts, but taking the "Thousand Dollar" approach of spending $1000 to fix the biggest problem you can seems to be the more common route, personally and professionally, for me.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071664 - 08/17/21 09:22 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
Not quite the answer I was expecting but that's OK. I'm not talking outside the bounds of correcting the biggest offender, and I'm not even talking outside the bounds of a small budget (aside from a very short but worthwhile excursion into the benefits of electrification.)

But I am talking outside the bounds of small thinking.

Last edited by MAP; 08/17/21 11:19 PM.
#1071672 - 08/18/21 03:01 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
Sutton used to always ask me what my limiting factors were, or more importantly what were my sacred cows that I wasn't willing to part with in order to achieve greater track results.

You sometimes have to pick your poison when trying to make a street car act like a racecar. One of my limiting factors then and still today is the desire to not completely rearrange the rear suspension geometry and style on a whim. Packaging is tough under there and trying to keep full exhaust tucked as well as ride height where it is complicates matters even more, not too mention the immense amount of fabrication and parts that would be required to do it the way I think would be necessary to achieve the results I would want.

I may get there someday, we'll see. Right now I seem to be way more interested into personalizing my new truck and making it better so the car just sits waiting for race season to start up once again.

I just wish I would have tried the huge front bar WAY earlier instead of fifteen other types of bandaides...that would have saved me 5 years worth of headaches and not too mention cubic dollars. My desire to help others in similar situations is the only reason why I keep preaching this. I know of at least 4 other G bodies currently competing that would LOVE the results of a 1500# front bar...maybe one day some o them will try it as well.


Lance
1985 Monte Carlo SS Street Car
#1071677 - 08/18/21 08:18 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
Well, as I said before, the larger front bar will almost certainly get the job done. I've already gotten on my soap box about other options so I'll let it lie. I'm amazed at the hoops we force ourselves to jump through in order to make a front-heavy car handle well.

Increasing front roll stiffness, along with having most of the car's weight on the front axle, puts the overwhelming burden of cornering acceleration on the outer front tire. This is fundamentally a recipe for understeer and reducing the car's lateral grip. Yes, you can use other factors to compensate, but it's not the quickest way around a corner, even if you're already at 1.2-ish g or whatever. That's one of the main reasons why that Tesla 3 beat you and everyone else, Lance.

Btw, "1500#" is only half of a (presumed stiffness) specification. What's the other half - e.g., per inch of deflection at the end of a swing arm on the sway bar?

Last edited by MAP; 08/18/21 08:32 PM.
#1071685 - 08/18/21 10:47 PM Re: Front sway bar project [Re: MAP]  
Joined: Sep 2006
Posts: 159
mrengineer Offline
10+ Year
mrengineer  Offline
10+ Year
Member

Joined: Sep 2006
Posts: 159
The D, MI
There is another option that I am frankly surprised does not get mentioned more often. You can easily remove about 150lbs off the front end by going with an LS and trust me you will feel the difference.


Mr. Engineer
#1071698 - 08/19/21 04:15 AM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
I couldn't agree more. Just switching the battery from the engine bay to the trunk was instantly discernible, and that was only 40lb.

#1071699 - 08/19/21 01:02 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
My left front is already heavier than the right front, removing weight from the right front by relocating the battery would only make that worse while at the same time make the cross weight ratio worse as well. There are times and certain courses where my car gets noticeably faster when I put a 150# passenger on the right front seat. Lighter is not always faster.

There are also plenty of real world examples as of late where guys have put smaller width tires back on their cars and went faster as well. I suppose there is an engineering formula for the amount of weight pushing down on a tire vs tread width for finding maximum grip but I'll stick with what I see actually working for people on course who are going faster.


Lance
1985 Monte Carlo SS Street Car
#1071703 - 08/19/21 07:09 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Sep 2006
Posts: 159
mrengineer Offline
10+ Year
mrengineer  Offline
10+ Year
Member

Joined: Sep 2006
Posts: 159
The D, MI
Great reference for all.

I recommend this book to every Formula SAE team when doing tech inspections. If you want to run fast, this book will help you understand what it takes.

Fundamentals of Vehicle Dynamics R-114, by Thomas Gillespie
https://www.sae.org/publications/books/content/r-114/


Mr. Engineer
#1071704 - 08/19/21 07:42 PM Re: Front sway bar project [Re: mrengineer]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
Originally Posted by mrengineer
There is another option that I am frankly surprised does not get mentioned more often. You can easily remove about 150lbs off the front end by going with an LS and trust me you will feel the difference.


Cory Carstensen just corner balanced his recently LS swapped G body and the weights came out very similar to what they were before with his SBC. His car is a bit different than mine as it has no AC and is a T-Top car but here's his scale sheet (includes driver weight).

[Linked Image]

This was mine when I weighed it recently also with driver weight.

[Linked Image]



Last edited by SSLance; 08/19/21 07:59 PM.

Lance
1985 Monte Carlo SS Street Car
#1071705 - 08/19/21 10:04 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
Some interesting points:

  • Crossweights and such: a car is a three-dimensional body. Front-to-back weight distribution is only one dimension. There are two more to play with. I never think in terms of crossweights because I find it unhelpful. I get all I need from comparing all four weights and looking at F/R, R/L symmetries. It amounts to the same thing, but is more direct.
  • LS conversion and essentially the same weight: if the motor reduced weight, then something else added it back unless we find a way to violate physics. That, or the swapped LS engine had an iron block. A 150lb weight reduction would be for an all-aluminum engine like the LS-7.
  • Lateral maximum friction / normal loading: the lighter the load, the higher this ratio; the relationship is monotonic. Tires don't obey Coulombic laws of friction. If they did, tire width would make no difference.
  • Narrower tires in the back make the car faster in corners: with a front-heavy car, no surprise. Narrower tires increase slip angle, so doing that at the rear reduces understeer.

Lighter is always faster when properly balanced. Correcting an imbalance by adding weight is always a sub-optimal solution. It's like taking a dish of spaghetti with too much sauce and adding more spaghetti to restore balance. Someone will get heartburn...

Mr. Engineer - thanks for the link but the price of entry is high. Great book with a great reputation. I have RCVD by Milliken and that answers most of my questions: I hope there's significant overlap here so I'm not missing too much by not getting this book (?) "I recommend this book to every Formula SAE team..." Sometime you'll have to tell us more about yourself.

Also, you'll understand that when I speak of weight, what I'm really referring to is the entire inertia tensor.

Bob - if you're still reading, I hope this doesn't discourage you in any way in your sway bar efforts! All the stuff I'm talking about is kind of second-order for you; just ignore it if you don't find it helpful. smile

Everyone - I wish I could take you all into this hypothetical situation: you're doing some enthusiastic corner-carving in your MCSS, and suddenly, I remove 400lb from the front end while conserving ride height. I predict you would be so gobsmacked floored with the improvement in handling that you would think, "Why on earth didn't I do all I could to reduce front-end weight before all of those years of band-aiding the problem?"



Last edited by MAP; 08/19/21 11:58 PM.
#1071712 - 08/20/21 01:33 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
I wholeheartedly agree that taking 400#s off the front of these cars would make them much faster on track.

The surgery and sacrifices needed to do that though are unrealistic for most of us that still use these as street cars also. Whereas adding a big stiff front sway bar is still pretty street car friendly.

Regarding vehicle dynamics engineering...this is what I've run into over the years but realize my experience is pretty limited on that kind of research. Most of the examples and data that I've read regarding handling, lateral load transfer, front vs rear grip and neutral balancing are all done and practiced on vehicles that were designed to handle in the first place. I've yet to see any engineers try to use math to get a 57% front heavy car to handle. Does that mean they can't get those cars to handle also or just that they've never tried?

My personal extensive experience in doing just that proves that it can be done fairly well but does take a bit of a different approach than what most of the books say. The difference is. I don't say they are wrong, I just contend that I've found a different way to skin that cat that works pretty well also. What I've also found (by real world on track experience) is that a lot of the "rules" that are used and applied on the books don't really apply to a setup like mine. For instance, a huge front sway bar will induce understeer...that just flat out hasn't ever happened...even though the books all say it will. My point is, yes it's unconventional but it also works pretty damn well and reality and practice is actually much easier than trying to confirm these cars to the type of vehicles the books say to use.

Oh and Mark, I've seen guys put smaller tires on the front of our big front heavy cars and go faster. More weight on a smaller contact patch actully pushes the tire harder onto the surface and creates more grip. I watched racers learn this first hand when Good Guys limited front tire size on a lower class couple years ago so racers went from 315s on the fronts back down to 275s to get into the lower class...and they went faster...not slower than before. When they win an event, they get bumped up a class anyway so theoretically they could put the 315s back on but several guys I know stayed with the 275s anyway.

Again, first hand on track experience...using out of the box methods.


Lance
1985 Monte Carlo SS Street Car
#1071717 - 08/20/21 04:34 PM Re: Front sway bar project [Re: MAP]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
Originally Posted by MAP


Lighter is always faster when properly balanced. Correcting an imbalance by adding weight is always a sub-optimal solution. It's like taking a dish of spaghetti with too much sauce and adding more spaghetti to restore balance. Someone will get heartburn...



I want to explain a situation that I've been in often on course to help make my point about adding a passenger to help get faster. Our cars are NOT properly balanced and they will never be in their current form. They are ALWAYS left side heavy unless there has been a ton of surgery done. When we have a course that has an overabundance of right hand turns or one or two very critical long right handers...my car will most certainly be faster overall with a 150# passenger in the right seat. 100%...every time. Like a LOT faster... Like the difference between winning an event or finishing third faster.

The mod of putting a passenger in the right seat is WAY easier than removing 150 pounds of fixed weight from the left side of our cars. Plus, it's more fun for both the driver and the passenger.

We are allowing guests at our autocrosses again this fall Mark, I can't wait for you to come up for an event and go for a ride-along with me.

2021

Sept 19 Sat

Oct 16 Sun

Nov 13 Sat

Dec 12 Sun

2022

Jan 16 Sun

Feb 12 Sat

Ma 12 SAT and Ma 13 Sun (Two day event)

Ap 23 Sat

Sept 18 Sun

Oct 22 Sat

Nov19 Sat

Dec 11 Sun


Lance
1985 Monte Carlo SS Street Car
#1071718 - 08/20/21 08:24 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
Thank you, Lance. Much appreciated. I'm not planning any trips to PHX soon, but looking to move possibly to Tucson. Housing prices are over-the-top crazy right now in all of AZ; looks like the tidal wave from CA is responsible at least in part...

With a sole occupant in the car, yes, the car will always be left-heavy. The factory designed the car to be kind-of L/R weight neutral with a certain cabin load that one must assume was not just a single occupant. If I were building an MCSS now, and knowing that about 99% of the time I'd be the only person in the car, I'd shift a lot of weight (read: battery weight) to the right to give me nominal L/R parity.

Yes, if you start left-heavy, adding weight on the right will probably help. But it's still not the optimal solution; heavy surgery is.

None of what I'm proposing to do is easy, but again, when you look at all the compromises and contortions and struggles we go through to "polish the turd" as Bob likes to say, in the end I think radical surgery is best and probably the path of least total resistance.

But do it at the beginning of a project, not at the end. That's why if I had a blank-sheet MCSS on my hands right now, the first order of business would be the radical surgery. A good rolling chassis that needed a paint job would be the best starting point. I'd lower it a bunch and widen it to conform to the width of a Tesla S/Y or thereabouts. Unibody conversion, of course, to maximize chassis stiffness in relation to weight.


Last edited by MAP; 08/20/21 08:35 PM.
#1071742 - 08/22/21 03:26 AM Re: Front sway bar project [Re: mmc427ss]  
Joined: Sep 2006
Posts: 159
mrengineer Offline
10+ Year
mrengineer  Offline
10+ Year
Member

Joined: Sep 2006
Posts: 159
The D, MI
You guys are going to force me to look up the weight delta between LS w/ iron block vs. SBC, asm as shipped. I have a detailed comparison somewhere, but from what I remember it's approximately 150 lbs. Also, G body w/LS, non AC & w/t tops weighing the same as Lance's....... does not sound right. Devil is in the details when comparing weights. And MAP, my kids cheapest text book for school was about $180 in 2019, books ain't cheap!


Mr. Engineer
#1071752 - 08/22/21 10:06 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
Lance, somehow I didn't see your post 8/20/21 1:33PM (1071712) until now.

Addressing that: Stiffer front bar versus heavy surgery - of course, the stiffer sway bar is a couple of orders of magnitude easier. I'm not saying anything to the contrary. What I am saying is that when you add up all the years and dollars and head-scratching and digital-ink spilling and GoPro recording and consultant consultations and autocross testing and trying this, that, and the other thing and then the other, other thing, and then the other, other, other thing, you could have been ahead by this time doing the heavy surgery at the beginning. That's what I'll certainly do once the opportunity presents itself.

"I've yet to see any engineers try to use math to get a 57% front heavy car to handle." Nonsense. Engineers do it every day, but mostly with FWD. Today, I don't think any OEM in their right mind would design RWD with 57% of the vehicle's weight on the front wheels. GM might have gotten away with it back in the 70s and 80s, but the base model in this case was a vehicle designed for transporting families in comfort. (The Fiero was a curious exception in several ways.)

Huge sway bar and less understeer: in an A/G body, decreasing body roll does a bunch of good things that reduce understeer such that increasing front lateral weight transfer at the front with the stiffer bar relative to the rear, can still result in a net reduction of understeer. Further, we're often surprisingly insensitive to how much our cars may be understeering. Taking a corner faster than before tends to make a much bigger impression, from which we may falsely (or rightly) conclude that our cars are understeering less. Did you ever test your car?

"More weight on a smaller contact patch actually pushes the tire harder onto the surface and creates more grip." If you mean the same weight on a smaller patch, contact pressure goes up, but the tire isn't being "pushed harder" into the pavement. Provided that the contact patch area is relatively conserved as a function of tire loading, grip will go down, not up. A narrower tire may still corner a little faster if there's a significant camber problem. Basically, wider tires are more sensitive than narrower ones to tire verticality. But mismatches between tire width and rim width can be exploited to cancel camber errors to a certain extent - in the case of positive camber, using a tire that's narrow in relation to the rim can be helpful.

I know it's tempting to think that if a set of solutions works on the track yet theory says it shouldn't, then the theory is wrong. Far more often, the truth is that the theory is simply incomplete or only partially applied. In 1933 Einstein said, "It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.” Or, as it's often misquoted, "Everything in the universe should be as simple as possible, but no simpler." The problem I've seen nearly every time in my engineering experience is that we oversimplify. I think we're seeing that here...

So, Lance, you've done amazingly well with the tools at your disposal. No one's denying that. But you haven't achieved the last word in what's possible, and that's where you'll need theory.

Mr. Engineer - yes, I know about crazy-expensive college textbooks. That's a captive market that's often unfairly exploited in my opinion. But no matter the market, that Gillespie book is too rich for my blood at the present time. But I repeat, I'm assuming RCVD can tell me all I need to know? I do have that book. Also, an LS-7 relative to an iron-block SBC-1 with aluminum heads is about 130lb lighter as I recall - I'm guessing that's where you're getting 150(ish) lb. The presence, or not, of various accessories may be obscuring the true weight difference.

Last edited by MAP; 08/22/21 10:31 PM.
#1071770 - 08/23/21 04:44 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Apr 2011
Posts: 1,187
Hunter79764 Offline
10+ Year
Hunter79764  Offline
10+ Year
Member

Joined: Apr 2011
Posts: 1,187
Grand Prairie, Tx
I don't have scales to back anything up, but I went from a 4.3 all-iron V6 to a 5.3 iron block/aluminum head/plastic intake V8, and my soft front springs stayed the same, if not possibly sit a little higher. If you are starting with an SBC with aluminum heads and intake already, there is less difference when keeping the iron block, but otherwise there should be a noticeable difference. I've researched to see how much, and it is amazingly difficult to get reasonably accurate weights on engines, especially apples-to-apples with accessories etc included.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1071783 - 08/23/21 09:29 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
Over the years I'd had many engineers tell me that "by theory" what I've done will never work. I guess I just look at things differently because I'm out there wrenching on my car, then racing it, figuring out what doesn't work to my liking, then wrenching on it some more, until I get it like I like it. I've learned a ton along the way about suspensions and how to make them work as well as how to drive to best suit that day's setup. It takes the whole complete package to be near the top of the charts these days. I know that target is getting harder and harder to chase these days especially with our handicaps, but that doesn't mean we still can't have fun nipping at their heels in our old luxury cruisers.

Fall of 2019 at Good Guys in Scottsdale, I was on my small 275s on my big, fat, front heavy, street car and I had ALL of the Speedway Motors team with their professional drivers and their team of engineers scratching their heads because I was 5th overall on the speed charts and ahead of all of their cars and drivers except for Al Unser(and I was only about a half second off of his time).

[Linked Image]

I'll never forget watching them send one engineer over at a time to walk past my car, bend down to take a look under and feel my tires to see if they could figure out what I was doing to be so fast. It was awesome!! By Saturday the majority of the fast guys had worked their way back up the charts and things were "more normal" but I was still ahead of two of the Speedway drivers (one was Mary Pozzi if that rings a bell in a 600 hp 68 Camaro). Two of the cars that got past me...did it by bolting smaller tires on if you can imagine that. There were circumstances that day that just worked in my favor and I was able to take advantage of them...it happens.

I know this, I'm not going to try to tell the engineers reading this that they are wrong...but I am going to keep sharing what I KNOW works with those that I feel can take advantage of my experiences and learning at the school of hard knocks. I KNOW that if Bob welded a front sway bar similar to mine on his car, he'd have a hard time getting the grin off his face after his first run on an autocross course with it. It's life changing...and not that hard to do with hardly any side effects. If I would have done it 5 years earlier, it would have saved me a TON of years and dollars and head-scratching and digital-ink spilling and GoPro recording and consultant consultations and autocross testing and trying this, that, and the other thing and then the other, other thing, and then the other, other, other thing... Just saying...


Lance
1985 Monte Carlo SS Street Car
#1071850 - 08/29/21 07:50 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: May 2002
Posts: 4,311
MAP Offline
15+ Year
MAP  Offline
15+ Year
Member

Joined: May 2002
Posts: 4,311
Yuma, AZ
That's all fine, Lance. There's no motivation to attack. Only to learn what's really happening down to first principles which oftentimes can be a nastily difficult thing to achieve.

So, you say you know x,y,z. Bob will copy/paste x,y,z and will probably get great results. But are those results truly the best? Almost certainly, no. I repeat that a Tesla 3 beat you and the whole rest of the group - that's one powerful existence theorem. Even so, if copying/pasting x,y,z puts a grin on your face and makes you happy, then have at it and enjoy it to the fullest. But there's still more - there's always more - on the table.

You said engineers couldn't figure out why you do as well as you do, but this is based on what - a five-minute exterior judgment? I doubt that they said what you do "couldn't work," but that it was improbable that it could work as well as it does. A deeper dive will always reveal why, and from the why, we will always learn ways to improve even more on what's already been achieved. You have not re-invented the wheel, Lance, although I'm not saying that you haven't done very well.

(Btw, one more question about the stiff front sway bar and going faster around turns. Is this while coasting the throttle, or while applying throttle to accelerate? What about braking while turning? The answer could exert a powerful influence on best front/rear roll stiffness balance. Basically, the more we're asking the rear to longitudinally accelerate a front-heavy car while turning, the less rear roll stiffness we want. That maxim should be etched in our frontal lobe...)

About what you could have done five years ago or however long it's been since you bought your car, there are other things you could have done that would have likely helped you even more than just using a very stiff front sway bar. Usually, at the start of a complex project, we vastly underestimate its difficulty and cost, and thus relegate too many options as being inviolable "sacred cows." Then we rue the fact years later after struggling so hard to work with just the un-sacred cows. I know you've dug-in your heels too far to want to admit it, but if you had started with an LS-7 years ago - another sacred cow - I contend that you would have been ahead by now.

I will repeat, as I have over the years to hundreds of engineers, never underestimate the power of questioning assumptions at the level of first principles.

(Bob - I've done a lot of talking on your dime. If you want me to stop, just let me know. Thx.)

Last edited by MAP; 08/29/21 08:22 PM.
#1072424 - 11/07/21 07:23 AM Re: Front sway bar project [Re: mmc427ss]  
Joined: Jan 2000
Posts: 5,421
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 5,421
Pottstown, Pa
Speaking of dimes it's maybe time to get a hundred rolls of dimes and maybe build a "bigger" front bar. With the cold days ahead sourcing the parts and seeing if a three piece bar can be squeezed under the front of the car could get done this Winter.
If done correctly the rate of the new bar if found to be "uncomfortable" could be easily swaps to a lower rate.

There are a couple ways of mounting the torsion bar. I'd like to do the bar in tube type as the tube adds stiffness if it's welded in. The big problem there is it would need to be mounted forward of the idler arm, like the stock bars. In that location the arms of the bar are long, this reduces the rate. A very high rate, thick bar, would require even a larger tube.
The other option i looked at was above the idler and pitman arm, right against the frame, maybe 1 1/4" clearance there. The length of the arms needed is much shorter. An advantage to having the bar in this location, rearward, is chances are the tires will not touch the bar at full steering lock. 11" section width tires require a little more working room up front. They don't touch the 36mm bar now, but that is possible with the selection of other parts, steering box and spindles used. With the three piece bar installed forward there is that problem again.

Still need to go back to the bar rate calculators and plug some number in to see what rates can be had with playing with torsion bars and arm lengths. Would like to be in the neighborhood of 1000 and move a little higher or a lot lower with just a bar change. One of the reasons the tube type bar appeals to me.

When I pulled the new autox tires off for the Winter a week ago did some measuring to see what's possible. So headed in the right direction.
Those RT660 tires are now nice and warm for the Winter, stored at room temp till getting called again with maybe a new front bar setup.
Bob

#1072435 - 11/08/21 01:21 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
Keep in mind that if you position it rearward and use much shorter arms, it'll be much more difficult to keep the endlnk ends from binding in travel up and down. When looking and measuring, consider moving the endlink attachment point to LCA forward. This will let you use a shorter arm while still leaving bar near the stock location and bind minimized.


Lance
1985 Monte Carlo SS Street Car
#1072447 - 11/09/21 05:29 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Jan 2000
Posts: 5,421
mmc427ss Offline
20+ Year
mmc427ss  Offline
20+ Year
Member

Joined: Jan 2000
Posts: 5,421
Pottstown, Pa
Lance refresh my memory, what size bar and length of the arms on your setup.
Bob

#1072452 - 11/10/21 01:56 PM Re: Front sway bar project [Re: mmc427ss]  
Joined: Dec 2007
Posts: 6,499
SSLance Offline
10+ Year
SSLance  Offline
10+ Year
Member

Joined: Dec 2007
Posts: 6,499
Peoria, AZ
From memory, 37" bar, 1.25" ends that step up to 1.375" center section.

1485# with 8.25" swing arms


Lance
1985 Monte Carlo SS Street Car
Page 2 of 3 1 2 3

Random Images
500/thumbs/front_seat1.jpg
by Rodney
1113/thumbs/BadAssFender7.jpg
by Z65_Paul
500/thumbs/Monte_Carlo_at_CCWD-06.jpg
by upflying
500/thumbs/old_pics_084_-_Copy.JPG
by MaverickMonte85
1125/thumbs/IMG_5004.jpg
by The PC Surgeon
Help MonteCarloSS.com


Recent Contributors
86BlackSuperSport
dns87ss
Authorized Vendors
Tell them you saw it
on MonteCarloSS.com!


CustomMonteSSParts.com
Dixie Monte Carlo Depot
GSI Interiors
HRpartsNstuff
Mikes Montes
Savitske Classic & Custom
Powered by UBB.threads™ PHP Forum Software 7.6.0