What's the angle ° of the engine/ trans.?
Printable View
What's the angle ° of the engine/ trans.?
Sorry Deuce, didn't see your post 'til after I did. :eek: :D
I just grabbed some magnets and stuck the bars whereI could on the way out the door last night and snapped some pics.
Yes Techinspector, I read all of Billy Shopes stuff, twice!:eek: I am still trying to understand all of it, but I am getting it, slowly. I have started a scale drawing to help me work it out. For instance, how do you locate the upper and lower bar locations on the rearend?
The real reason for propping the bars up was to ask, can the upper bar be inboard (closer to the center of the car)from the lowwer bar? (see pic below)
The angle of the trans is about 6 and the pinion is a little less in thse pics is about 4 . I am thinking I need to lower the front of the motor and then lower the pinion some to match the angles. This would reduce the angles of both u joints.
Duece, I could go triangled 4 bar but the upper arms would still be short and at a pretty steep angle to meet the frame behind the seats. Just cant move the seats forward any more. What do you think about that?
Sorry for being such a lamo but I am getting it.:D
Thanks for all your help.
dog, I went back and read my post and it sounded like I was being condescending when I asked if you didn't understand. That was not the way I meant that question at all. I probably don't understand what I'm doing and have just been lucky. :LOL:
Question from your post:
For instance, how do you locate the upper and lower bar locations on the rearend?
They can be anywhere you want them to be, within reason. Your drawing looks reasonable, with lower rear pivot about 8" from the ground and upper rear pivot about 16" from the ground. At least, that's what it looks like to me. Anyway, here's a quick drawing to 1/8 scale with 28" rear tire, 24" front tire and 110" wheelbase. I put in 3 instant center lengths....60" (minimum you want to use), 70" and 80". If a guy wanted to make front attachment points for each instant center, he could experiment. I laid all the instant centers on the squat/anti-squat line. You can put them over or under the line to alter the behavior of the car if you wish. The solid lines are the 60" instant center lines, the dotted lines are the 70" instant center lines and the dash-dot lines are the 80" instant center lines.
Using 12" links, the front attachment points are as follows from the ground with the three different instant centers.....
60" top bar 15.040", bottom bar 8.600"
70" top bar 15.492", bottom bar 8.780"
80" top bar 15.944", bottom bar 8.960"
Using 16", 20" and 24" link lengths will of course alter the distance from the ground to the front link pivot points. I have no idea what length you can squeeze into the car.
This is just measuring off my 1/8 drawing with a dial caliper and multiplying times 8, so it is only close, not dead nuts. You, of course, will do your own drawing and arrive at your own figures. You can mount the front attachment points off any length instant center you want, even extending it out in front of the car. You can also use any % anti-squat you want by dropping the instant center below the squat line. I forget now how many attachment holes there are in a pro car, but I think I have seen as many as 96 different combinations and it has been said that only 2 or 3 of them will work in any given car, depending on wheelbase, instant center length, etc., etc.
Thanks Techinspector, You have realy helped me understand this.
I have spent a few more hours on Billy Shopes site (thanks to your condescending answer:LOL: :LOL: ) and am starting to have a working knowlage of how it all works. Now with knowing that the 2 pivots on the rear end can be just about anywhere, within reason, I can start doing some calculations with different instant centers, % of rise or squat and bar legnths.
By gosh, I thinik I'm gonna get this figured out!:3dSMILE:
First though, I have to solve my driveshaft problem. With the engine and trans where I want them, I have a 15* working angle on the u-joints.:eek: Thats not gonna work, so I am tilting and raising the motor and that will change the CG.
I am the kinda guy that has to know the how and why things work, then I can build with confidence.
Remember the "How and Why wonder books"? I loved those books as a kid and had to have them all.
When I was 10 years old, my mom bought a set of World Book Encyclopedia. She couldn't afford them, bless her heart, but she somehow bought them anyway. By the time I got to high school, I just about had them worn out from leafing back and forth and reading. So, I am familiar with what you're saying. :3dSMILE:
OK, I have spent quite a bit of time studying the whole issue of the 4 link system. I still dont quite understand all of it but I'm gaining on it.
When using bushings like these (picture below) from moog, does it matter which way it goes in?
I would assume whatever I do on the right side of the car, its opposite on the left.
Also, I understand that the upper and lower bars need to be the same length (or close) to not change the pinion angle during travel.
I can only get about 13", eye to eye, on the top bars.
That is also a comfortable length for the lower bars.
Is that too short to work properly?
Thanks again to all who have participated in this thread and my education on rear suspension. I really apreciate it. Couldnt have done it without you.:D
And while I'm on the subject of rear suspensions-
Techinspector, In your drawing of the different instant centers, (Thanks) , How does one decide what to use.
I have read much about % of anti-squat.
All of your instant centers are at 100% anti squat (on the neutral line)
Let me know what you think about this. Its the part I dont understand yet.
The site below talks about this (see diagram below)
http://www.baselinesuspensions.com/i...A_Drag_Car.htm
This is taken from that page-
Normal/Neutral Line:
1. Draw a line up through the center of your front wheel.
2. Draw a Horizontal line through the CG until it crosses the line drawn through your front wheel and mark this intersection point. The Normal Line (or Neutral Line) is the line drawn from the Rear Tire contact patch through this intersection. Neutral Line
The location of the IC relative to the CG and the Normal Line (or Neutral line) is what determines what the chassis is going to do. One term used to describe the chassis movement for a 4 link suspension is Anti Squat. An IC that is located ABOVE the Normal Line is said to have more than 100% Anti-Squat. An IC located BELOW the Normal Line is said to have less than 100% Anti Squat.
~4-link settings of 100% Anti Squat should accelerate the car w/o any raising or squatting of the rear of the car.
~4-link settings with MORE than 100% Anti Squat will Raise the rear end and hit the tires HARDER.
~4-link settings with LESS than 100% Anti Squat will cause the rear end to Squat and hit the tires SOFTER.
~IC's that are located IN FRONT of the Center of Gravity (CG) will tend to lift the NOSE of the car.
~IC's that are located BEHIND the Center of Gravity (CG) will tend to lift the REAR of the car.
I think equal length is desirable but many factory rear coil setups use unequal. I also like the idea of the top bars being triangulated.
I do too, Willowbilly. But I dont have the room to get much angle on them.
I've thought about this unequal rear length (shorter on top) and have come to the conclusion that this is to maintain pinion angle closer to zero on acceleration/bump. If you look at the geometry on a front suspension, you'll see that the top arm is always shorter than the bottom arm. What this does is allow camber gain in bump, so that the tread of the tire remains more parallel to the road surface on bump, instead of rolling under and losing traction. If you look at the rear suspension from the side as we're doing here and think of it as a front suspension, a shorter top link would do the same thing. On acceleration, the pinion climbs the ring gear (or tries to) and results in a less than desireable pinion angle relative to the front/rear u-joint relationship. As the diff rises (or body drops depending on how you look at it), the shorter top bar will introduce the same "camber gain" into the differential that the shorter upper control arm on the front suspension uses and counteracts the tendency of the pinion to change the u-joint angle.Quote:
Originally Posted by willowbilly3
Now, again, I see it this way because of the way the factory sets up a rear suspension for the diff to rise (body drop) in the car on acceleration. I have never seen diff drop (body rise) on a factory car. I've seen it on Mopars that were set up for drag racing, but not on factory installs for grandma going to bingo. Now, if a guy were to set up the instant center at a point that would generate body LIFT (diff drop), then I would think that the shorter top bars would be a detriment and maybe even going the other way with longer top bars would be advantageous. Then again, I could be wrong.
Instant Center Length: Somewhere in Billy's explanations, there is the statement that the instant center should not be less than 60" from the rear pivot points. He said the center could be out ahead of the car in thin air, but not shorter than 60".
Link Lengths: Here's a thought. You have the links connecting ahead of the diff tube, which limits the length of them with the available space ahead of the diff. What if you were to make your diff mounts behind the diff tube and lengthen the links. Angles on bump and rebound wouldn't be quite as acute and as a result, the instant center wouldn't change so drastically in bump and rebound. I could see re-inforced triangular plates mounting the links maybe 11 inches behind the diff tube and giving a link length of 24". This should also give you a little freedom to angle the top links and keep from using the dreaded Panhard bar :eek: to control lateral movement. You would have the added benefit of not twisting the rubber bushings as far circumferentially. Think about it and tell me if I'm all wet.
It won't matter which way you install the rubber bushings, but you must make the ID of the receptacle steel bushings compatible with the step on the rubber bushings. They are a press fit. I would have one of the OEM control arms in my hands to carefully measure them to get it right before turning the steel bushings for fit.
Instant Center: Like I said in an earlier post, with a drag race 4-link, there are somewhere just short of 100 different combinations of placement of the IC. If all cars and all conditions were equal, then there wouldn't be but one set of holes in the forward brackets. But that obviously is not the case. I think the best you can do is to make the IC at least 60" long and put it on the squat line as your center set of holes. Make as many adjustment holes up and down from there as you wish to make so that you can experiment with the placement of the IC for your particular combination of weight, wheelbase, CG and road/track conditions.
In my opinion, here it is in a nutshell.....what you posted above....
"~4-link settings of 100% Anti Squat should accelerate the car w/o any raising or squatting of the rear of the car.
~4-link settings with MORE than 100% Anti Squat will Raise the rear end and hit the tires HARDER.
~4-link settings with LESS than 100% Anti Squat will cause the rear end to Squat and hit the tires SOFTER."
The Mopars I have seen that raised the body obviously had the IC set ABOVE the squat line in order to hit the tires harder. If you're raising the body, that means you're pushing the diff down.
The current generation of very fast cars I see at Firebird neither rise nor squat. On launch, the body remains where it was in relation to the diff when the car was staged. That tells me that they must have the 4-links set somewhere close to 100%.
Or you could run the links rearward toward the bumper
Here's my idea of extending the link mount back behind the diff....
And here's (I think) Jerry's idea of extending the links to the rear for attachment.....
Just playin' around here because I love to do this sort of thing. I'm working on my desk with a ruler at 1/8 scale. If any of you other guys like doing drafting/drawing, a dandy board can be had for cheap. Go to one of the home improvement outlets and buy a door. Cover it with a smooth, thin sheet of linoleum and make a down and dirty stand for it from some inexpensive 1 1/2 X 1 1/2 lumber. Makes a dandy board and you can easily draft out 1/2 scale automotive projects. T-squares and such can be bought pretty cheaply from drafting supply outlets. Drafting 1/2 scale and dividing the lines with the sharp points on your 6" dial caliper can get you pretty darned close. When done with your drawing, multiply times 2 and you have the dimensions for the actual parts.
Anyway, here's another idea for limiting lateral movement of the diff without having to use a Panhard bar. In my opinion, those things are an engineering abomination and that Panhard guy should have had his head pinched off as a baby.
Just wondering Techinspector, what do you have against panhard bars. What have they ever done to you!?
As the diff goes through bump and droop, it follows an arc created by the Panhard bar as the bar swings up and down. The bar will be at its longest at rest and will become shorter in both bump and droop, pulling the diff laterally in opposition to the main suspension components, which operate on a completely different arc. It is not in synch with anything else on the car geometrically. Sort of reminds me of an inbred child. Just not right.
As awful as it is, the characteristics of tugging and pushing of the bar can be minimized by intalling it parallel with the diff and making the bar as long as is humanly possible. That involves making brackets to attach it to the diff as far to one side as possible, all the way over to the backing plate. The bracket on the other side should mount the bar onto the frame all the way over by the backing plate on the other side of the car. It's still an engineering abomination, but at least in this manner it's a minimized abomination.
Agreed..... A Watts linkage takes a bit more planning and requires even more room then a panhard bar...but they do work a whole lot better....
Quote:
Originally Posted by Dave Severson
Watts that? :HMMM:
:LOL: Sorry I just had to say it..... :LOL:
Go to your room. :D
While I have to agree that a Watts would work better on a car that had a lot of rear end vertical travel, with the couple of inches that the typical hot rod moves up and down a panhard doesn't have much of a chance of "arcing" the rear end from side to side. I would bet if you measured the sideward movement caused by the panhard during that couple of inches of up and down travel it would amount to maybe 1/8 of an inch.
Look at how many rods are running panhards, many coming from well known chassis builders. Then name how many Watts setups you see.
Don
Quote:
Originally Posted by techinspector1
:LOL: It's been one of those days. :LOL:
Draw him a picture Techinspector.:DQuote:
Originally Posted by pro70z28
Thanks for all those drawings, but could you make the links blue instead of red? I want to see how that would look.:LOL: :LOL:
Yeah dog, I'll get right on that....**)Quote:
Originally Posted by maddddog
:LOL: :LOL:Quote:
Originally Posted by pro70z28
Somebody had to do it~!!!!!
Don, I know many chassis builders are using them, but does that make it right? I don't think so. It just makes it cheap and expedient. If the Panhard moved the diff laterally even 0.001", it's still in conflict with the main suspension components that are moving on a different arc. What's wrong with the Satchell Link arrangement I drew? If you're gonna make four links to bolt on the car anyway, what's wrong with angling two of them and not having to fit anything else to control lateral diff movement?Quote:
Originally Posted by Itoldyouso
Granted Don, it may not be much, but the panhard bar does mess up the handling.... When you're really cranking it into a curve and the back end goes over a bump it will push the car considerably...
I've also been amazed at the IFS guys who will spend hours getting the front end geometry just right--then just hook up a panhard bar on the back because it's the generally accepted method of doing it....
As for naming some cars with Watts linkage......well, mine... Perhaps I'm not a pro shop, or even a shop anymore far as that goes but nevertheless, right is right and as long as there are curves and corners with bumps in them, a panhard bar will never be the correct method of controlling lateral movement of the rear end housing.....
On the rare occasions that I actually keep something I build long enough to actually get it completed, I'm not going to let something like a panhard bar instead of Watts linkage screw up the handling that I spent so many hours and $$$$$ getting correct on the front of the car... Maybe I just drive mine a bit harder then most or I'm just to particular about how the suspension works.... If a builder is not going to comprimise anything on the front suspension, why ignore the rear suspension????
That was some good info to know. I was wondering cause I have very minimal experience with chasis setup, and my camaros have panhard bars. Think I may go to a 4 link setup when I get the money.
Speaking of triangulated 4 links (read as in Mustangs) and panard bars ( si in Camaro) we have actually put some panard bars on Mustangs for the autocross racers----they actually take a lot of that sideways movement out of the four link bars---and yes, I know that they are now 5 bars----
Jerry, I think we have reached a point of equalibrium. You and Don use 'em all you want. Dave and I won't use 'em at all. :LOL:
I don't use them on anything I have personally
But we have installed some on a couple of national championship autocrossers---they are limited to lots of specs and the panard bar actually helps with the stock bushings in the ford bars
Personally, I like a solid rear end as in dragster or funny cars
So, If I havnt made up my mind yet, shouldht you guys be sending lobyists to my shop to first, fabricate and install the panhard and then the watts so I could break the tie once and for all?:LOL: :LOL:Quote:
Originally Posted by techinspector1
the wAY the ground shakes out there you'll need all you can get under it
I had to take a couple days off but I am back on it now.
I went back and read the last couple pages and looked at all the pretty pictures again (thanks Techinspector)
I'm getting it. (thanks all)
One last question remains (yeah, right, Just one!)
Techinspector, you have allready answered it but I think there has to be more to it.
How do you determine the locations of the series of holes for the upper and lower bar on the rearend?
Techinspector, you have some radical suggestions in some of your drawings. Why do I usually see them slightly in front of the rearend tube, with the bottom series of holes slightly more forward than the upper holes?
There must be some reason for this. (On the other hand, I do like to make things more complicated than they need to be at times:eek: )
[QUOTE=techinspector1]Just playin' around here because I love to do this sort of thing. I'm working on my desk with a ruler at 1/8 scale. If any of you other guys like doing drafting/drawing, a dandy board can be had for cheap. Go to one of the home improvement outlets and buy a door. Cover it with a smooth, thin sheet of linoleum and make a down and dirty stand for it from some inexpensive 1 1/2 X 1 1/2 lumber. Makes a dandy board and you can easily draft out 1/2 scale automotive projects. T-squares and such can be bought pretty cheaply from drafting supply outlets. Drafting 1/2 scale and dividing the lines with the sharp points on your 6" dial caliper can get you pretty darned close. When done with your drawing, multiply times 2 and you have the dimensions for the actual parts.
QUOTE]
I had to go back and search for this one Richard.... Got to thinking about it today when the dog and I stopped for a coffee break out in the shop.... I'm going to do this for the Bronco II... Reason being the short wheelbase---any errors in my calculations or the geometry on a short (95") wheelbase could result in an ill-handling 'lil truck and some guardrail to guardrail excitement!!!!
Anyway, thanks for the most excellent idea Richard.... Maybe it will help this nearsighted old man avoid a few miscalculations!!!!!
U-DA-MAN!!!!!
I'm unclear on what you're asking here. If you're talking about the series of holes at the front of the bars where they attach to the frame structure, those are dictated by the arc swung by the bars themselves. Find a mounting point/arrangement on the diff that suits you and use a compass on your drawing to swing an arc based on the bar length.Quote:
Originally Posted by maddddog
No, I mean the holes on the rear end.
[QUOTE=Dave Severson]Thanks Dave, now you can bolt a 38" X 50" Vemco to the edge of the door and be "downtown" for only 400 bucks......:eek: :DQuote:
Originally Posted by techinspector1
http://www.nationwidedrafting.com/st...gmachines.html
[QUOTE=techinspector1]I think you're joking, but dont go spend $400 on one of those, I have one I dont use anymore and I will let you have it for much less than that!!Quote:
Originally Posted by Dave Severson
Thanks for the link, Richard!!!! Lots of neat stuff--and good ideas for a cheapskate like me!!!!! Doubt my drafting skills would justify 400 bucks---but I think I can make do with some aluminum pieces I have in the garage.... My drafting is far from technically correct, I'm sure, but it works for me, guess that's all that counts, huh???
I just really like the idea of getting the whole chassis plotted out at 1/2 scale and being able to sit back, drink coffee and analyze things!!!! With the price of materials these days, being able to get so much closer on cut and bend dimensions can easily save in $$$$ the cost of putting a big table together....