Predator

Thanks for the reply.

My experience exactly. I know what you mean about "feel" versus "measurable" improvement. I think the hardcore suspension guys don't give much credence to "feel" and are just concerned with measurable results. To me, feel is just as important.

RevGTO

iTrader: (12)

We can narrow the debate considerably by agreeing that SFC's make the car "feel" different. If anyone says that they can't feel the difference, then either his butt has no nerves, or he's already stiffened the car so much by other means that he can't notice it. The question is, does the difference in "feel" equate to an improvement? Apparently, not an objective one.

Predator

Is there an echo in here?

Seriously, that was my point exactly, and it seems to explain why Sam contradicts SFCs being an obvious improvement. I know the man knows his stuff, so there has to be a reason for the contradiction.

BADSS

iTrader: (7)

You'll get no argument from me about Sam. He truly knows his stuff and the great thing about Sam is this: he tries to STOP customers from buying parts they don't need. He actually tries to save his customers money, even when it costs him a sale. Now that's integrity.

I've bought shocks, swaybars, and a STB from Sam. I will also be purchasing some UMI SFCs from him for my '02.

When Sam says you don't NEED subframe connectors, he's right- particularly from a racer's point of view. If you want to go fast, why add extra weight to the car you don't need? It will only slow you down.

But a 4th gen F body will FEEL better on the street with subframe connectors, even if you cannot measure the improvement. I don't know how else to explain it.

Predator

What's ironic about Sam's advice though is that most of the people posting about SFCs are not driving flat-out race cars.

I wouldn't hesitate recommending SFCs to anyone with an f-body, but it does make sense that the cost/benefit of adding weight for a better feel, for an all-out racer, might not be the best way to go.

Sam Strano

iTrader: (41)

My all out racer has 40k miles on it (5k of which were put on in the last year), gets 29 mpg, is fully tagged, insured, has both air bags, A/C and the Monsoon in it. My car is a pretty whacked ESP autocross car, not a full blown GT1 car. In short it *IS* a street car with a lot of carefully worked suspension, headers, limited slip, etc. installed.

And I run on 315 R-compound tires all the way around. The car will pull 1.2g steady state with them. I put more stress into to chassis than anyone in a normal street car. The only folks putting more in are guys running on slicks with 500 HP and cutting like 1.6 or under 60's.

No contradiction.

Why is it so hard for you all to get it through your heads that saying they aren't necessary, or the first thing you need is DIFFERENT than saying they are of NO BENEFIT? I'm not saying that. I'm saying there are way bigger fish to fry first.

And to answer your statement about having SLP shocks first from a previous post. SLP takes compression damping away from what Bilstein HD's come with. Compression damping controls unsprung weight, you don't have less unsprung weight that would allow one to take that out. Basically it's one reason I don't use those shocks, because the valving is not all that good and it's changing the way impacts get transmitted to the body vs. getting damped out.

Again. NOT NECESSARY IN MANY CASES does not equal NO BENEFIT TO ANYONE.

Sheeh.

Foxxtron

iTrader: (1)

and for those who question my "feel" debate, I will remind you of the same question:

1. How old are your seats, have you replaced them, and are the replacements upgrades?

2. Bear in mind that I am still working on a video that I promised, which also include another driver. He like I don't know when the SFC's are on or off.

3. Also, one last question is, no matter how it's improved, what's that absolutely "sloppiest" part of the car concerning handling? (supposed to have some "slop").

EDIT: 4. What are strain gauges?

5. Do you remember reading this article? http://www.1le.net/docs/tittermary.jpg

If you did, can anyone (besides Sam, of course) correctly answer how to remove most of the "uneasyness" that was described with the 1LE in the article?

BADSS

iTrader: (7)

Some of us understand what you're saying, Sam.

Another point for those of you who aren't into autocross (or who might be considering doing it in the future): subframe connectors bump you up into a higher class in autocross, so there are solid reasons for leaving them off an autocross car.

Question for you, Sam- if you could run subframe connectors in your class, would you install them on your car?

01Z28M6

A strut tower brace from Sam . They're great for lifting an fbody from a detached K member when pulling a motor but I haven't read too many posts where people think they're good for much else other than cosmetics. Someone please educate me.

Sam Strano

iTrader: (41)

On my car, for what I do? I would if they were legal, but not before all the other stuff like actual suspension parts. A street car that doesn't go through what I put it through? Hard to say. Would depend on what I was wanting from the car, but probably not.

I was in a autoxing/instructing in Cobra Convertible last year that has SFC's, and you could feel it twisting and watch the cowl shake, and feel the windup in the body. My car does none of that on wider tires and no SFC's.

Sam Strano

iTrader: (41)

Understand that I'm here to make a living. Often I kick myself for threads like this, where I *could* say your 2 of this, 3 of these.... like most shops do. But no, I have to have a conscience and actually try and put the customer's needs before thier sometimes blind wants. Stupid of me, I'd make a lot more money just selling whatever.

He wanted a STB, we discussed it, he wanted it. I sold it to him. I'm here to sell parts. I'm done killing myself to talk folks out of thigs. I will always tell them if something is not maybe the best idea, etc. I won't lie or omit, but I'm going to try a whole lot less hard to convince them if they don't want to listen....... which is very much what has been happening in this thread.

BADSS

iTrader: (7)

Read my original post further back in this thread. I contend that I COULD feel a difference with the STB on my 99, so I am putting one on my 02.

My opinion on strut tower braces may not be in the majority, but there are plenty of F body owners who have claimed to be able to tell the difference. Including Trackbird, who is a pretty well respected member of this board and the frrax.com board.

I am on my third fourth gen (one LT1, two LS1's) and have been driving them for the past 13 years, so I think I know a little bit about them.

I'm not exactly a newbie.

Predator

Remember though Sam, you're really respected around here because of your integrity. No need to change your ways.

Sam Strano

iTrader: (41)

I'm only going to modify them slightly. If someone doesn't want to listen, I'm not going to kill myself making them. That simple.

Zymosis

iTrader: (7)

Exactly what I said from the get go man. A complete shock system can fix a problem, SFC cover up the problem IMO.

Just like the other guy said, integrity man, not many have it these days, and thats why people keep calling you. And thats why you will have my business when I begin my search for full shock/spring/coil setup.

Predator

I don't blame you for feeling frustrated with some of these threads, but in this thread it seemed, at least in my case, I was honestly trying to understand how not having SFCs could be beneficial in any way. I understand now. Since you have so much experience with this stuff, what seems obvious to you is not obvious to someone like me. Heck, I installed them on my car, felt a noticeable and dramatic improvement, and promptly concluded that all cars needed them. I see that I was too hasty, but only after participating in this thread. So you're frustrated with us, and I'm grateful for learning something.

Lastly, it's not enough, in my case anyway, to "listen" to someone and follow what they say without having an understanding. Even though I seemed to disagree with you, I never really doubted that you were correct. I just needed to understand too.

You are such a rarity among vendors, I'd hate to see you become disgruntled because of some unknowlegable replies.

todddchi

iTrader: (3)

I'd like to preface the following with the fact that although I am an long time f-body owner and enthusiast - I am absolutely not a supsenion specialist nor do I have any race experience with tuning the chassis of these cars.

I am however, a product engineer who works in vehicle NVH and have some things to offer to the discussion from a pure engineering standpoint.

Strain gages are used to measure loading put into parts. They are attached to the subject component and through extremely precise measurements of the deflection of the material it becomes possible to output the loads being placed into the part, as well as the deflections (magnitude and manner) of the part.

Therefore by strain gaging and collecting data on a pair of subframe connectors, it would be possible to develop actual data about how much load is being absorbed by the subframe connectors, and in theory, this would give you some finite measurement of how much of a benifit they are offering. The fundamental argument being if we show the subframes take up 1,000lbs of compression force under a given event - well, then they are doing something, and thus working.

From an engineering perspective there are several problems with this approach, and it has to do mostly with the way that inputs (loads) are put into the vehicle unibody and how the vehicle body reacts to those loads. Also how those body interactions make it to your physical body.

It is fully possible, that adding a subframe connector, and collecting this data could show that the subframe connector is indeed taking a good amount of load - forces that would usually be taken by the body are now being routed through the subframe connector because it is adding structure so the load goes there while the body yeilds. However this is not really concrete proof that they are providing a true and tangible benefit. There are many interactions in complex spring/mass/structure systems and in the way that metal parts deflect under load - that mean even if the subframe connector is now taking some load - it doesn't necessarily mean the overall behavior of the suspension system is truly improved.

From an engineering perspective, what would be more interesting would be to collect NVH data on cars with and without subframes. This could be the key factor in why some people "feel" a big difference, while others do not. Every person out there has a different sensitivity to NVH inputs. For example some people get motion sickness, some people do not. Some people can pick up a 200 Hz buzzing in subframe, some people could care less.

I suspect that this is the key problem. Subframe connectors may in reality offer a NVH benefit that is "feelable" and therefore many people like them. While in fact they could offer very little in the way of actual chassis tuning. Again from an engineering standpoint Sam is 100% correct in that things such as tires, unsprung mass, and damper tuning are much more important than frame stiffness in cars like ours.

I know, and have seen data, where a SIMPLE damper change can result in 2-3x as much load being transferred through the system. When you consider all of the different tires/wheel sizes, springs, ride hieghts, suspension condition, and structure age of all of our cars, as well as varying brands of SF connectors, combined with everyone having a different ability to evaluate the differences at the seat... well it's no wonder the opinions are all over the map.

From Sam's standpoint I can tell you that a simple addition like subframe connectors - in our cars - would have very little overall influence to the body movement (rotation and translations) compared to changes in the wheel/tire, springs, bushings, and shocks. We're talking a ratio of maybe 100 to 1, and that is not an exaggeration.

But let there be no doubt - there is a key difference between NVH tuning (feel) and real chassis tuning (handling and response). For example right now I am dealing with a product in driveshafts that has a resonance frequency of +/-10 Hz. When the parts are at +10Hz - there is a noticeable, audible boom in the vehicle. When the parts are at 0 or -10Hz - the boom is gone. Silent. Given that the subframe connectors are pretty much sitting right under your butt, things start to make sense.

I think the comprehension of that may be what is missing here. People think they are arguing about the same thing, but in fact you are not.

Foxxtron

iTrader: (1)

Thanks todddchi,

Since working with materials can get one busy, that helped that you took some serious time into explaining it. I explained that with brakes at one point, but it took much time away from what I really focusing on.

Now for the viewers of most of my posts, I never said that feel wasn't important (quite contrary), it's just that they are two seperate aspects that cannot be confused, plus "feel" is always considered, however I have noticed human factor scientists/engineers are much more accurate with determining any links with "feel" and "handling." What I am doing is merely concentrating on improving chassis/suspension tuning and less on feel, since I have learned that simple feelings can create many confusing driving habits.

more of my cheap 2 cents.

Predator

Well, the most important thing that I've taken from this thread, and it's a revelation, is that "feel" is not the be all and end all. This is very interesting to me. In the future with any changes I make, I'll note the "feel" but certainly not conclude that things couldn't be improved. Thanks.

WS6Drop

iTrader: (10)

Another good example that may hammer the point across is, just because a car feels fast doesn't necessarily mean it is. Data from the dragstrip is really the only way to quantify real life quarter mile performance.