Ratchet

Ok Now that Ive got your attention I just wanted to share an experience I had While working on my 87 RS.

This Car has No rust on the undercarriage so it is still very solid. Yesterday I was putting the Car up on JackStands to do some work on it and something funny happend.

When I let the Car down on the back two jack stands one of them did not touch the rear subframe that it was sitting under.

After looking at it a bit I realized that it was because that jack stand although the same height as the other three was sitting in a hollow spot in the garage floor that leads to the floor drain.

But guess what the car is so solid (no subframe connectors) that you can push down on one corner and the car will actually rock on the two jackstands that are slightly hgher. With the car supported on only two jack stands right front left rear and a friend balancing it that way( the other two jack stands are under the car about 1/8th of an inch away from touching the frame) I can open and close the doors just as I can when the car is sitting on the ground.

What gives I thought these things were supposed to flex all over the place. This thing is like a brick, it is solid. I am not saying that SFC's are not a good Idea I just don't understand why this thing is so solid.

Has anyone ever done any actuall testing of chasis flex before and after SFC's?

Ric

RB83L69

Place on floor is ½" lower, car only bends ¼", whatever....

You don't have the only solid one of these cars that exists. Every single other one of them is weak. SFCs make a difference.

Lots of people, myself included, can give you their experience; but I don't think anybody has ever posted measurements. If you do the right thing to your car, measure the flex before, and measure it again after, and be very careful to set it up exactly the same. It would be good to know.

patrickm00

while i don't have add-on SFC's, i can say from my experience of driving 2 t-top trans ams and now a conv, that the conv flexes more even with the factory-added reinforcements under the doors.

i don't have the experience to say how much of an effect they'd have on a hardtop or t-top, but i'd expect to notice a difference on a conv for sure.

87 B4Z

the $200 i spent on SFC's was the biggest waste of money i have spent i on my car. it feels no different then it did before, still feels ****y while going down ****y roads and the car still creeks while going up steep incline’s. i owned and a hard top 3rd gen before and have driven a few hard top 3rd gen's after buying my t-top'd car and they all feel alot better then my car even with the SFC's.

sllt1776

well i think it also has to do with the cars history. what the previous owners did to it and where it was driven. my car was pretty solid too. the thing is that eventually it would begin to weaken just like the rest. i did notice a small difference when i installed the sfc's but the main thing is that i don't want the car to get worse. i think the sfc will stop the weakining process.

85TPI400

87 B4Z,
Just curious, What kind of SFCs do you have?

Dewey316

i feel like my SFCs were the BEST $200 i spent on my car. the SFCs made a night and day diffrence for me, i have pictures of my parked on funny inclines and it will hold 1 wheel of the gound. i don't regret doing SFCs for 1min in fact if i had known about them soon i would have done them as soon as i got the car.

87 B4Z

i have the spohn

Wishmaster's87IROC

iTrader: (4)

and here I am getting ready to buy some SFC's because of the posts ive read about them and now this comes outs......saying they are a waste of money...well WHAT NOW!.....

Dewey316

how many people have siad they are the best mod they have done....

there iss only 1 person saying it was a waist

Wishmaster's87IROC

iTrader: (4)

true..........but you never know, most people just feel a difference in there head and justify spending the money and say they were the best mod just to get others to buy them too and on and on and on. Now its the best mod ever,,

maybe this person was being honest but your right this is the first one Ive read that has said it was a waste of money.

I just dont want to waste money too..I mean $200 is alot for something else. im looking into getting the Spohn's

Jekyll & Hyde

I felt a difference as soon as I sat in the car. I also have a t-top car, so that made an even bigger difference. Look at all of the 12sec and lower cars and notice that they are all running them. Hmm, now why would they do that if they could save 20lbs.

Jekyll & Hyde

Given that, where are the creaks coming from? Have you installed a "Strut Tower Brace"?

87 B4Z

the noise is coming from the top of the car somewhere behind me. yeah i have a STB and i was able to tell more a difference with the STB on and i have had the STB long before the SFC's.

Jekyll & Hyde

You might have gotten a wrecked car that wasn't claimed. It made a huge difference on my car. Plus you can't go wrong to help keep the stability in a 11-21 year-old car. Sometimes t-tops will rattle in the connection part. The piece that slides in the a-piller and the sail-panel. Might want to see if they are loose at all. The first thing to do is see if they move event he slightest bit with them locked down. If they do, then that is the problem. I'm not saying that I don't have any squeaks, I have the infamous hatch squeak right now. That is pretty much it. Check that and let us know how that is. It might just be some loose or misadjusted parts on the car tight now. Trust me, as the car ages, sub-frames will be a hugh difference on the car.

JamesC

iTrader: (5)

I have an 85 IROC coupe that's been treated well. Flex? You bet. Shoot, inspect a coupe's roof just behind the drip rail and you'll more than likely to see a fine crack (on both sides of the car). That said, I'd think that converts and t-top cars would flex far worse. Buy the SFC's; they stiffen the car in a way that GM should have done in the beginning. By the way, I'm using Global West's SFCs now. Good product.

JamesC

82camaro

Adding just subframe connectors to my old 82 made a huge difference. Corners better, launches straighter, and is way more stable driving on the rough roads around here. I really wish I would have done this mod first.

GTA-SPD

SFC's a waste of $$$$????? Honestly they were the best thing I ever did. The ride got noticably harsher and more noisy over bumps than before. That is the only thing I noticed bad, well the noise is bad the ride is ok by me. The time I really know that they are there is when I throw the car into a corner, it really responds now, with no creaks & pops. As for your bad experience, do you have weld in ones or bolt in ones? The bolt in ones are not the greatest piece. I have South Side Machine weld in ones, and man did they stiffen the car up.
Coincedently, I used to work in a junkyard as a mechanic, and cars that were hit hard enough to tweak the uni-body would rock on my lift. Just because it rocks on your jackstands, doesn't mean that it doesn't need SFC's. Trust me, get some GOOD weld in type connectors and you will not be sorry.

87 B4Z

i have spohn, they only offer a weld in version.

Wishmaster's87IROC

iTrader: (4)

The ride got harsher and more noisy? what do you mean noisier?
how much were you SSM subs?

vjo90RS8

iTrader: (1)

I have no regrets spending 200 for my SFCs and it would be the first mods i would do it to any thirdgen i buy in the future.

Jekyll & Hyde

I too wish that it was my first mod.

Maybe the suspension wasn't properly loaded. Sometime it will look like it is, but it really isn't. Sometimes the car has just been through to many rough roads before sub-frames. Could be a bunch of things.

GTA-SPD

The car is more rigid and bumps & vibrations from rough pavement are not absorbed by the chassis flex any more. The noise is the same thing, noisy may not be the best way to describe it, but that's as good as I can come up with. Don't get me wrong, it's not like a covered wagon (well it is, but NOT due to just the subframe connectors), it just has very positive road feel. I got my SSM's from Summit (I can't remember how much, but far less than $200) and they were at my door in 2 days.

llvll4l2c91350

Now I'm having second thoughts again. I wanna get rid of all the rattling but at the same time don't want the ride to become harder. It feels hard enough already.

formul8!!

Sub Frame Connectors are THE BEST thing I have done to the car. It should have been the first mod when I bought the car 9 years ago!!

They will not cure all the rattles, but the ride is much better, the chassis doesn't quiver nearly as much, and it doesn't groan when backout off a curb.

I also picked up a full 1/10 off my 60ft time. It hooks much harder than before the SFC's.

llvll4l2c91350

Does the ride feel harsher since you installed 'em?

89transam

I have had sphon subframe connectors on my car for about 2 weeks now and I am just loving it.

At first I kind of dissapointed cause It diddent stop all the creaks when I would go over a steep driveway or dip. I mean I could definatly tell the difference in just how solid the car felt, and it seemed like it hooks better now too. Overall its just a better ride.

But then, one day , It was really nice out and I took the T-tops off. Over hills and bumps...no creaks or groans whatsoever. THe car feels perfect without the tops on, I think all the remaining noise is just my junky t top weatherstripping rubbing the windows or something.

Buy em..

CrazyHawaiian

Some people seem to mistakenly think SFC's are a 'fix all' for our cars. Installing SFC's wont instantly make all your rattles go away, nor will they instantly improve your ride. They are a single part in a long list of parts you you need use to achieve the perfect ride. I consider them a building block to a successfull suspension setup. Chassis flex is one of the worst things you can deal with because it is unpredictable. SFC's really tighten the chassis, and this gives you a better platform to build your suspension on. Of course if you have old, bad, or cheap springs/shocks/struts/bushings/etc SFC's wont make a huge difference. You'll still need to fix/replace the rest of the parts to have a good ride. Building a good suspension setup is alot like building a good engine setup, All the parts must compliment eachother. SFC's are a MUST. Some people see very very good results (like 89transam or Dewey316), and thats probably because the rest of their setup is in tip top shape. If your suspension is not in tip top shape, then SFC's might not make that much of a difference. But it is the right place to start.

formul8!!

Actually, the ride got better. Instead of the chassis soaking up suspension flex, the suspension now does more of the dampening. The car feels much more solid. I have changed all the bushings which also made a major difference.

GTA-SPD

It sounds to me like you are looking for "cushy" ride and great handling and feel. I don't know how you are going to achieve this, since in order to make these cars handle like they are on rails you have to stiffen the crap out of them. Chassis flex and suspension deflection consumes the horsepower that you have already. A lot of times cars get quicker and perform better with the addition of chassis stiffening components. The more rubber you replace with polyurathane, the harsher the ride is going to get, likewise with the struts/springs etc. As you remove chassis flex and improve rigidity in the suspension, the car is going to lose some (or most) of it's Caddy like ride (which is good if you want to carve corners). If you have rattles, chances are that you have interior panels, t-tops etc that are loose or not attached as well as they used to be. The plastic clips that hold every interior panel to the car deteriorate over time and the panels become loose and vibrate. What causes this to happen comes right back to chassis flex. You can replace those clips and do it again every 5 years or so, or you can stiffen the car to eliminate the flex that causes them to go bad and Slove the problem. If you stiffen your car, the ride is going to get more STABLE, but it will be more responsive (what I formerly called harsh, I think responsive is a better description). How much feel you want is entirely up to you. In my car you can feel everything from expansion joints to tar lines, which is exactly how I wanted it. I have spent a substantial amount of time and money to achieve the ride I have. No, my car may not be the most comfortable car to go cross-country in, but damn is it a joy to drive through the mountains on twisty roads. Basicly you have to decide how far to take your suspension upgrades, SFC's alone will not make your car an unbearable beast to ride in (though you will notice a difference), but without them those rattles that you hate will only get worse.

poncho@home

GTA-SPD

What kind of times are you running with your GTA?

llvll4l2c91350

The thing is probably around 90% of you guys have improved the performance of your powerplant significantly while mine is still pretty much stock, so of course you are gonna have to beef up your suspension. My car is a daily street driver and I don't ever see myself trying to make this car into a beast. I know for a fact that all the rattling won't be solved by SFC's alone, but I would like it to feel at least a bit less noisier (my previous 88 Formula felt more comfortable to ride in). Also I don't know about putting urithane bushings. I swapped my tranny mount once with an urithane one and the whole car got a vibration on the road. I had to put the stock rubber mount back in. But for most of you guys vibrations or harshness aren't problems, since you don't have to sit in your car everyday driving it. I wouldn't be contemplating about this subject if I had a 350 putting out 300+HP and another car I could drive too. The SFC's and new bushings would already be on the bird.

Dewey316

llvll4l2c91350,

i drive my car EVERYDAY , i put about 20k a year on it.

i have the mods listed in my sig. the SFCs made my car NICER to drive everyday, it may pick up slighly more road noise (but if it does it is a min. amount. and it seems by your name that you have a 350, which means you probably have 70HP more than i do. if i were you i really wouldn't worry about SFCs ruining the drivability of your car, if anything it will make your car a better daily driver for many more years. because the SFC really do help keep the car in better shape.

but that is just me $0.02.

poncho@home

Tightening up your chassis is a no brainer. You need to have a tight chassis with as little deflection/flex as possible and then let a good set of shocks take car of the dampening. Just look at all the latest cars going to market, ultra rigid chass and they feel great. Don't get misdirected into thinking to rigid is no good, it 's the exact opposite of that. Rigid is very desirable...after that you can make a car smoother and "less stiff" by using softer springs and shocks, but atleast you are letting them do there work instead of the chassis absorbing energy.

Have you driven the new Nissan Altima? It has an extremely rigid chassis and it feels great.

Wishmaster's87IROC

iTrader: (4)

I know this might sound stupid but how does makin the chassis stiffer put the power to the tires or should I say pavement? Or meaning how would having SFC's take off my ET's?

Also whats the word on which is better? Spohn, Hotchkis, SSM, alston..what?

thanks guys

llvll4l2c91350

I wish I knew someone with a third gen F body with SFC's installed so I can drive it and see how different it feels. And I know I'm saying that I will never go nuts modifying this car, but I shouldn't say never, cuz that can change if I start learning more about engines and modifying them, (I've learned quite a few things so far from being on this board) and if I ever get a good job where the money permits it. One thing at a time though,,,I think right now the next thing I do to the car is coat the headers. The paint has completely burned off and they look ugly. Plus with the hot FL weather having arrived now, I'd like to keep the underhood temps low. Once I'm done with that I will look into the Alstons.

poncho@home

The flex caused in a chassis that is not rigid is a waste of energy. In other words to twist your frame requires energy that you are not applying to the only thing that should be twisting, your drivetrain. Also a more rigid chassis is easier to control and to predict rather than having a chassis that flex at will depending on load and the weather!

All this will equate to a faster more responsive automobile!

GTA-SPD

She runs HIGH 15's on the best day, but low 16's consistently. Keep in mind though those times are at 5280 feet of altitude with a completely stock motor (other than headers). I'll be more proud of the times with the new motor I'm sure.
On a side note, I also drive my car everyday, unless I'm working on it, or there is ice on the roads.

To expand on this answer, when you mat the go pedal the torque of the engine causes the chassis to flex BEFORE that power gets to the rear axle wasting that power. If you don't believe the flex is that bad, look at the sail panel on your car (especially if it's got the 5.7) and notice those cracks in the metal. Not only does chassis stiffening help with planting the power you have, it makes the car respond to steering input better, as well as improving all around handling. If you don't believe all of us, read the articles in Motor Trend, CHP, Hot Rod etc on new cars and high preformance cars and see the common thread. All of them boast about chassis rigidity. Stiffening up the chassis and improving the braking power are mods that should be done before you mod the crap out of the engine. Those roll cages they put in race cars are for more than just driver protection and we all know that a race builder isn't going to put any weight into a car unless it is completely necessary.

Wishmaster's87IROC

iTrader: (4)

is it better to get the SFC's that have the cross brace that ties to the tranny area? or does it really matter. Cause some manufactures dont have that...

formul8!!

In a thirdgen, the "harsh" ride is mainly because of chassis flex entering the passenger compartment and sending the bending frequencies in to your body. The less of these frequencies your body feels and the less rattles you hear will result in a percieved better ride.

Stiffening up the chassis the the BEST thing you can do for your thridgen. I also highly recommend a strut tower brace to compliment the SFC's.

I would recommend buying SFC's that run along the whole rocker panel and ties into the trans tunnel frame. SFC's with this design are made by Spohn and Kenny Brown.

llvll4l2c91350

Yeah that'll be next on my list after the SFC's.

pvknight

my spohn sfcs made a world of difference in carving corners, but didn't do much to quiet my hatch and ttop rattles

Dewey316

well it isn't going to cure everything, if you t-top hardware is loose, unless you fix that, it is going to rattle.

(BR)G-Machine

I dont want to flame or anything but you have to remember that you probably have a hard top that is of the newer veriety. They lose ALOT of structural integrity with T-Tops, age, and lower structure in the earlier ones.

I also think SfCs are a good insurance because I know a guy who put hos Formula into a curb with no SfCs and it diamonded the subframe with hardly any inpact at all. The car was a totally dead and he couldnt get an insurance money because there was no real "accident." Ie no cops.

Irocster

I just ordered my Spohn SFCs (haven't come yet). I can't wait! Anyways, way later downt the road I plan on getting hooker 2055s. Now since these SFCs are weld in, am I going to have any clearance problems with these headers (and Y-pipe)? Sorry, I know this post is old. Thanks

SteveSpohn

No

NJITIROC

iTrader: (2)

haha...
well said Steve!
i have my spohn sfcs on my car, and they are very very good. not too shabby on the delivery time either.
thanks bud!

Ratchet

Ah common guys who dug up this old thread. I'm embarrased now for asking the dumb question If you read my original post here you will see that it was a question not a statment. The answers I got way back then obviously convinced me that subframe connectors are a good Idea. See other posts of subframe connectors installed in our project car.

Oh yeah! Please let this post die I think I was on stupid pills the day I started it

Irocster

Proud to say I brought it back!!! It's alright man, we understand your stupidity. j/k