And then you have guys who only want to share something they did and the details therein when they're trying to discredit or knock someone else. They don't do it with the motive of furthering the sport of drag racing, nor to actually help the less experienced people out. It only serves to either line their pockets, or to stroke their big delicate ego so they can say: "look what I did, and what you didn't do" very childish and IMO that's just one of the many reasons why drag racing is a dying sport.My response about my suspension setup from 1993 as a 19yo kid, going consistent 1.41 60' in 45F degree weather, and my friends 1.37 60' , with zero suspension plotting, a factory rear roll bar and a $50 airbag with 8lbs in it, $23, 3-setting shocks, $20 in steel to box factory arms, and some ES bushings was in regards to your statements above, and telling the other guy there was no way he went low 1.3s without doing your plotting program. You're twisting my words here, but I won't assume the worst of you as you have me, and instead I'll assume that you misunderstood me, and that's the reason that you've taken what I said out of context. I told him that there's no way that he got his car to turn those good short times by merely having the correct pinion angle. my point was that he obviously got a whole lot of other things right other than just the pinion angle. That was the whole point I was making, and you missed that.
The basis of my post was that while the ARB's, DA shocks, weight Jacks, multiple plotted points adjustability and some software is nice and makes for a much improved, controlled launch,YES!! Thank you for admitting that. So you and I can now agree on that... it is not mandatory for the majority of street/strip cars the TC members drive on a daily basis.And how many TC members do you think there are who actually drive their Chevelles literally on a "daily basis" and also drag race them at the drag strip?? Especially those who post ion this Performance forum? There might be a few but I'm pretty sure they're in a small minority. I gave two first hand examples of stock suspension setups with pretty respectable 60' times, with basic parts that can be done on a low budget and some thought and understanding.
But your attempt at mocking me about using an airbag and trying to compare that to an 8 second setup is noted. How did I compare that to an 8 second set-up? My point was that even for 10 second cars, bolt-in rear anti-roll bars are a much better way to go than airbags are, and I also gave you the benefit of the doubt by stating that that car that you mentioned was likely set-up in a time when airbags were one of the only things available to you. So I gave you credit where I believe it was due, but you still choose this war of words by taking things I've said out of context.
This isn't even an issue on A or G body cars with OEM or Ford housings and OEM mounting locations.
You seem really confused here about a simple and common rear end setup for A and G body cars.I had worked a very long shift when that picture was posted, and because his picture cut out most of the rear end pumpkin, I didn't even notice that the pumpkin was in the pic at all, and about a page or two later in this thread, I posted a comment about that same pic that when I took another look at it after getting some sleep and being well rested, it was obvious to me what it was. But you didn't read that, did you? Or did you deliberately leave that part out in an effort to discredit me? And yet you are able to "know about" where his IC was,Dude, there you go again pulling things I said out of context, because it just so happens that my comment about "knowing about where HIS IC was" did NOT have to do with the pic you're talking about. It had to do with Vinny Laurita's 70 Chevelle. And I've plotted other 70 Chevelles with the same tire height that Vinny has, and the exact same rear suspension components that Vinny has on his car, and in the exact same mounting holes in the same mounting brackets that Vinny has made by UMI Performance on their lift bars that Vinny has which are the same as I have on my 70 Chevelle, and that's how I know where his IC location is within about a 4 or 5" margin. ...but nobody else can possibly use more the 350-400hp on a stock suspension car without plotting it out? There you go again twisting my words. is this some personal vendetta of yours? I didn't say that nobody will be successful using more than 400hp without "plotting out" their suspension. Why don't you look at the entirety of what i said??? I said that when there is above 400 HP under the hood with these cars, it becomes "Increasingly difficult" to get them to hook consistently with the factory IC location being way out in front the car. That's what I said. NOT what you claim. How much more misinformation will you spew out????
Did you eyball the CG too?
Where does the IC come out when you don't have to worry about the upper arms and change the lowers? Ever tried going fast with a bunch of power and a short and high IC? I would never do that because the end result would be that the hit on the rear tires would be too intense and too short since the tires would rebound hard back up into the rear wheel wells and the car would wheel spin out of control beginning about 5 feet off the starting line. Now for the benefit of others reading this, I will make mention of how there is one race car fabricator who overcame those negative points about using a very short instant center, (it was merely a 22" IC length) by using really heavy custom made rear coil springs that are about as heavy as stock BB front coil springs are, and he clamped them to the rear end axles as well as to the chassis so they would act as dampeners to aid the rear shocks to prevent that rebounding effect of using a very short IC on 10 second cars and it works very well. However his reason for doing that doesn't apply to most street/strip cars since he merely did that to avoid the no welding rule on stock Eliminator drag cars which are limited to the number of suspension mods that can be done. But I digress....
The amount of contradicting advice here is impressive.
Besides taking Daves classes, reading his book, and plotting out points in your program, I am wondering what actual experience with making changes to an actual car you are driving and testing these changes that qualifies you to give any advice? I don't need your approval nor your "qualification" either, nor do you need mine. Why don't you ask Dave Morgan that question as to what "qualifies" to give people advice since he never speaks in his book nor in person about ever owning or even ever driving a drag car?? or didn't you know that about him? But his advice still works very well by your own admission, right? I don't know everything that dave does, nor did I ever claim that. But besides the brief experience I do have, (maybe even more than dave himself has with drag racing).
I've helped a number of guys out with their Chevelles. "Crazy Davey" being one of them. He came to me on this board and in a private message wanted me to plot out his rear suspension on his white 67 Chevelle that he ran mid 9's with. he was having traction issues with that car when he came to me and after I helped him out with the software I use, that car hooked great. he isn't the only one, but he was the best known. Maybe you might remember the videos he posted on here of his his car running at the track. But what does any of that have to do with suspension geometry??
For being a student of Dave, you seem to ignore the fact he talks pretty thoroughly on the effects of pinion angle and traction.Not for 4 link cars he doesn't. He didn't in his seminars which included updated info to his book, and I don't remember reading anywhere in his book where he states that pinion angle has anything to do with traction in 4 link cars. But I invite you to show me the page that includes that or at least tell me what page number you found that in and I'll check it out, and if you're correct that I'll acknowledge that no problem. But I don't think it's in there. And you've yet to show us that.
I ask what your actual experience is when you state that 5" of travel is preferable, without knowing any other factors? But there ARE other factors, and I made mention of that. But here again you take one sentence of what i wrote and run with it to accuse me falsely. Are you on some type of mission here???
Is this a " Gotcha" response?
Because I can certainly respond to each point, but I've already written way more than it's worth in response.
I see zero mention of Dave Morgan or his book in your posts. OK, I'll acknowledge that, but the reason is that I used to make mention of Dave Morgan on here and some people would pu pu it. So there are times when I leave out Dave's name because it seems there have been certain people on here who don't care for the man nor his theories. I don't understnad why that is, but I try to avoid controversy by leaving out his name, but that is in no way an effort on my part to take credit for anything that dave has done. In fact, there are still times when guys on here write to me that I will tell them about Dave Morgan.
The diagrams in his book are good reference for the details you have skipped over, and would make good visual explanations for members that can't eyeball plotted points by laying under a car. Well then mr. race car engine builder judge, then if that bothers you that I left that out, then why don't you assist in helping others out like I am trying to do by posting some of those diagrams yourself since you have your cell phone camera going here in this thread??? Don't you think that would be more constructive and helpful to our fellow drag racers than this verbal competition that you've chosen to engage me in with your false accusations????
I noticed you completely skipped anything about corner weights and spring preload, and it's effects.
I see zero mention of IC in relation to CG. So you're telling me how I should write my posts and how I should share information when the only time you choose to share information is when you chime in to argue about something. If you have more to add than I have, then by all means sur join in with some more helpful info!! And I would welcome it a whole lot more than you turning this entire thread into a childish war of words which does absolutely nothing.
I see zero information or related experience of your personal car, how fast it has gone, what it weighs, what the front/rear bias is, suspension plots, etc. I take it that means you have no data to share from your personal car? That because this thread is NOT about MY personal car nor about yours. It's about "optimal Instant center" and the geometry associated with that like the title says. There are enough guys on here who don't do anything to help people out, but only want to keep their secrets as to what has worked for them while they post pics of their impressive cars just to boast. I'm not saying everyone here is like that, but that's what I miss about guys like Bob West when he used to be on here when he had his 71 Chevelle. When he posted vids and pics, he would answer anyone's questions that they had. He wasn't just on here to sell something nor to boast. I wish that can be said about all or even most of the very experienced drag racers on here. There are still a few left on here like that, and I for one admire them for being that way.
Apparently my response and examples didn't set well with you, and you felt the need to knock "old" tech and attempt to educate me on what and why my car appears as it does in the photo.
I've learned in my relative basic experience that some people will spend dollar after dollar on parts that they don't understand, because they believe it's required to accomplish certain goals.
Meanwhile, the ones that don't know, are out doing it.
Thanks for ruining this thread and turning it into a personal battle between you and I. Really worthless to everyone. You could've offered your knowledge and experience in a non-combative way, and offered a difference of opinion,(as MONK did in post #89) and I would've fully respected that and the thread would've remained productive and useful and even became more useful. But instead you came at me with an axe to grind. Congratulations on accomplishing absolutely nothing.