I recently had some Spohn SFCs welded onto my '89 IROC with T-tops. I expected to hear less noises from the car when driving after the installation, but I'm really not impressed at this point. Most of the noises I hear are best described as "popping" sounds. For example, whenever I'm braking, usually just before the car actually comes to a stop, I will hear a pop/thump sound comming from what sounds like the front of the car.

Also, I notice a lot of popping/thumping sounds come from the car when doing turns. In fact, just the other day, I was making a turn and I heard a very loud pop from underneath the car (didn't run over anything). I thought that one of the welds on the SFCs might have busted loose, but I didn't notice anything catastrophic when I inspected the undercarriage.

I'm starting to question the quality of the SFC installer. After he had the SFCs welded up in the front and the back, he called to tell me that the SFCs didn't fit very well because there were some gaps between the rocker panels that he claimed would be difficult to weld across. He ended up welding it anyway, but he did not seem very confident about doing it. Also, on the other side of the SFCs (the side that faces toward the middle of the car), he stated that he would not be able to weld the SFCs directly to the floor boards. Instead, welded some half-inch pieces of metal to the floor boards, and welded the other sides of the pieces to the SFCs--almost like little "bridges". It sounded like a good idea, but after looking at them, they don't look like they would do very much.

I would really like to quiet this car down if I can--that's a big reason for why I got the SFCs in the first place. Could a bad SFC install be to blame for the noises?

 

With a T-Top car that old, SFC's no matter what brand and the installers skill are not a Magic Cureall for all the noises & squeaks.
Just look at it this way, you made a improvement.

 

Popping and thumbing sounds usually make me look towards suspension stuff, maybe a bad exhaust hanger too.

 

It sounds like steering/suspension issues to me. SFCs will cause your steering and suspension to work more than they were before, since the body itself was taking some of the shock. That's what I would look at.

Those half inch spaces are supposed to be there, but I agree, I would question the installer. I had my SFCs installed at Spohn's garage in PA, and when they welded them up, they used what looked like little metal bars about a half inch square by 2 inches long. I forget what they're called, but that's the actual material that gets welded by the torch to connect the SFCs to the car. I would give Spohn a call and get some information, then talk to your installer. Honestly, it sounds like they did an ok job... metal tabs and welding material are the same principle anyway.

Start looking at your suspension and steering parts. You may also have to realign your t-tops if you're getting some sound from them, and take a look at your door hinges also. My passenger door makes some noise every now and then since the install.

 

umm, when he installed the SFCs, was the car on all 4 tires?

it COULD be that the car was tweaked on the lift when they were welded on, and now the suspension/steering isnt lined up like its suppost to be.....


but just incase its somthing else... try cleaning off the front suspension/steering, and regreasing everything with a zerk fitting.

 

I know for sure that my car was on all four tires on a lift when it was welded. I also know that the welder had me and somebody else sitting in the car armed with several spray bottles full of water. The installer told us to "spray the heck out of" the floorboards (since the carpet was off) once they got red hot. I had never been around welding before, so I really didn't know what to expect. From what I could tell, he must have melted through the floorboards on at least half of the welds on the floorboard--I know, because I can remember being damn near blinded from the illuminated floorboards, and pelted with hot welding (I wore shorts, like an idiot).

I really don't know if any of that was "standard procedure" when it comes to welding, but that's part of the reason why I question teh welder.

CaysE: I'm glad to hear that Spohn uses the same method that this guy used with the small metal "brackets" to the floorboards. I just questioned it because I don't recall the instructions saying anything about it.

Another thing he did that wasn't on the instructions was to cut a bit off of the short passenger side piece so that it welded into the larger SFC. The instructions said to weld the smaller piece *on top* of the SFC--I never did understand why. Actually, I think what he did looks better, and that's probably why he did it. I just wonder why the instructions said what they did--there must have been some good reason.

I'll go ahead and take a look at my front suspension. I'm thinking of fishing up torque specs on all of the front end parts and just going in with a torque wrench and re-torquing everything.

If I get the chance, I'll post pictures.

Thanks

 

whoa... that doesnt sound right

the floor boards can get very hot, but you should never see the welding light from inside the car... that would mean he burned a hole thru your floorboard...


the keeping the inside of the car wet however is standard procedure... alot of people use wet towels on the floorboard...

 

WOW! That is vary wierd. I just did mine two weeks ago and never had to take the carpet off or nothing. I went with the mac sfc and it made the car nice and tight. I vave t-tops too and the noises are almost gone. Might want to get a second opinion on he install.

 

The Macs get welded to the subframe and not the floor boards, thats why the carpet wouldn't get that hot. But I agree that the welder blew some holes through the floor, not that bad if he was able to close them up.

 

I bet when you get the carpet and stuff back in the car it will be quiter than before. The noises you described sounds like bushings, uper strut mount's and just plain worn steering parts. Replace the bushings and put in a wonder bar. The car should be quiter.

I just installed alston sfc's you can tell the body is tighter but, I still have noises, I have all the poly bushings ready to be installed and a TDS wonder bar also. Hopefully with the sound deadner I am also putting in with the new carpet, my car will be quite, except exhaust. I don't have a cat right now :-), When I pulled it off to do the welding I knoticed how bad it was, so I cut it off and welded in a pipe. Until I can buy a high flow flowmaster.

If I still am not impressed I will be adding spohn's next year. but I think once every thing is done it will be quite. I can tell you there is less movement in the dash now.

 

The popping noise just before the car comes to a complete stop is being caused by worn bushings. I've had mine replaced several times over its 18 year life span.

You can either go with the GM rubber bushings, which soften the ride a little, or with aftermarket polyurethane bushings, which will increase handling at the cost of a much stiffer ride. I'm still using the GM rubber bushings.

I am getting subframes welded on my car later this week...I hope the installation goes well.

-Anthony Helton

 

Aviator857: Actually, I'm hearing all of this noise with the carpet in . Moreover, the frontend has been rebuilt recently with all new Moog parts. The struts are new as well. The only thing I didn't change on the front end that usually gets changed in a front-end rebuild were the A-arm bushings--the ones that were in it just didn't look like they need to be replaced. As the car is an IROC, it has always had a wonderbar. I didn't think about the strut mounts, though--how commonly do those wear out?

Adam Jones: Which bushings specifically are you talking about? A-arms are the only ones I could think about and, like I mentioned, I didn't change those just because they didn't look that bad. I've done a front-end rebuild on my '88 Camaro SC before, and the A-arm bushings on that car looked bad enough that I replaced them.

 

The upper strut mounts is one of the things people forget, and they do wear out. Also, I say go ahead a replace the A-Arm bushings, the poping under heavy braking is normally Aframe bushings. Also check the gearbox and idler arm and make sure the bolts holding them to the frame is tight. What about sway bar end links did you replace them?

 

My car used to pop and clunk like hell too. My bushings looke new, but they wern't. When I pulled my control arms out, I had a hell of a time getting the bolts out, because they had seized to the metal sleeve in the bushing (which is more common than you'd think). After I replaced the bushings with poly's and replaced the hardware with new bolts (coated with grease) the popping is completely gone. I would also look at the frame rail by the steering box very carefully for cracks. These cars crack there quite often, and with the chassis being much stiffer now, you may have uncovered that little SNAFU. On a side note, my South Side Machine SFC's fit perfectly, and tightened up my car a lot. Also, not all IROC's had the wonder bar, my brother's didn't and neither did my GTA with the WS6 suspension.
By the way, those llittle "bridges" or "brackets" used for your SFC's are called shims and that is very common when welding SFC's in.

 

I'm talking about the A-Arm bushings. I'm about due for changing mine out. The car now pops occasionally towards the end of braking to a complete stop, but the bushings themselves look fine. I can almost guarantee that's the problem.

-Anthony Helton

 

I was talking about the same thing you were, I just call a-arms control arms because that is what they call them in the Hollander system. I also refer to the rear control arms as trailing arms.
A little more on this, I'd only go with poly bushings if you don't mind a bit harsher ride and more road noise. They will help your handling, but that comes at a small comfort price.

 

You know, hearing the popping sound when I'm braking, the A-frames were the first things that popped into my mind. If I understand the way the suspension on these cars works (which I only <i>barely</i> do), then most of the momentum of the whole car when braking is being opposed by the front brakes--and the A-frames are what are transferring that force.

I think you guys are probably right about the A-frames, and I should probably replace them. I actually wasn't aware that there were polyurethane bushings availiable for these parts. I know I just replaced the bushings on the rear LCAs, and I put the rubber ones in. I would like to put polyurethane on the front, but that almost makes me feel like I should do the same to the back. Like I said, I don't know much about suspension, but I've always been of the idea that you can't treat the front and rear suspension as completely separate components (although, physically, they may be).

 

don't forget to look at the subframe mounting bolts! They rarely do but can loosen up!

A-arm bushings are a must

Take a look at the brake hardware, sometimes the bushings get worn and the clips are missing from the pads this causes clicks and thumps.

Door hinges. grab an open door and lift it. at 90 degrees and as parellel to the body are you can. There are little rubber wedges at the top of the door where they meet the jamb, these also help quell rattles. Strikers get worn too!

strut mounts

engine and tranny mounts, tranny especially can cause a clunk when you come to a stop

Hood bumpers

If your car is lowered and it hits the bumpstops while driving over bumps, it will rattle much worse than over bumps that don't cause the car to bottom on the bump stops.

Endlink and sway bar mount bushings

Thats all i can come up with right now!