[Datsun40146]

Hello everyone,

Sorry about the cryptic title but I had several issues to discuss.
Background:
First of all I recently installed FM V-Maxx coil overs on my 99' Miata which is when this popping noise started. The car is set at 12.5 front 12.75 rear as per FM recommendations. The car is running stock wheels with 195 series tires.

Problem Number One Description (Suspension):
The pop noise occurs only sometimes when I'm stopped (such as at a stop light) as I let out the clutch and the car just starts to move forward as the weight begins to transfer. The pop is quite noticeable and is higher pitched like a twang/pop combo sort our sound. Also I hear a pop when the car has been sitting for a period of time and I get in. As in soon as my weight (140lbs) hits seat I hear a light pop. I'm not sure if the two are related but they could be as they both started around the same time. Which was when I installed the coil overs.

Attempted Solution: I have checked the torque on the alignment bolts, sway bar end links and ball joints for tightness. These are all quite tight with no perceptible movement. The shop checked both upper and lower ball joints and could find no movement in them. I initially thought some of these would be the cause as I had to remove the upper ball joints and sway bar end-links to install the coil overs. However, I did not find any fault with those components.

Problem Two (Brakes):
This one really isn't a problem but after the Auto-X this weekend I was hard on the brakes a lot and obviously was really throwing the car around. After the race I noticed that my brake pedal was much higher and firmer than it was before. That's awesome! As I had recently installed new pads and bedded them in but never had the pedal feel this good. I want to know why! Why is my pedal so much better after the race?

Current Car Modifications This might help in diagnosing the problem.
Converted to Manual Steering (Welded Pinion Shaft)
FM solid front sway bar
FM V-Maxx coil overs
FM Butterfly brace
Race-land Header
FM Mid-pipe
Brainstorm dual exhaust
Koyo Aluminum Radiator
Hawk HPS brake pads
Stainless clutch line

 

[Datsun40146]

Any thoughts on this random noise, its making me drive my car less hard and I don't really like not beating on the car. Its meant to be driven hard, and I can't freaking about a unknown noise.

 

[1vicissitude]

Did you properly torque down the coils at the right time? If you tightened the bolts on the tophat while the wheels were suspended in the air they more than likely are not fully bolted down. The extra space on the threads could be catching and making a "popping" noise when loaded. The bolts will feel tight because they are pulling up the wheel and suspension weight even though it's still loose. All four wheels need to be on the ground before tightening the bolts on the tophats to the car.

You could have also it tightened the center bolt on the shock shaft when reinstalling the nb tophats onto the vmaxx. I do not know the proper torque specs or routine for vmaxx coils but I'm sure FM does.

Try calling FM. They know their products better than anyone and have great support.

 

[mysteryskittle]

I agree with Vicissitude on the thread catching and making the popping noise. Even if one nut is a bit loose, it will catch the threads when weight is shifted. The center strut bolt not being tight enough may be a cause but it usually makes a clunking noise over bumps.. not on level ground or when you sit in the car.

Did you check the bushings and brackets on your sway bars? They can be noisy if the the bolts arent super tight. Also, make sure your calipers are tight where they bolt to your hubs. The pads can clank around if they are loose. That's probably not your noise problem since the pads are new and thick.

 

[Datsun40146]

I had all the wheels on the ground when I began to torque the mounts. The shaft started to spin on the mount by the time I was done tightening the nylock nut. They were quite tight as far as I know.

 

[mysteryskittle]

How doe the endlink/sway bar look? Everything tight?

This may sound dumb, but check your lugs and studs. They can back out of the hub slightly and "pop" back and forth as the rotor spins. If you checked everything else, it might be a simple problem you overlooked. Are your springs seated properly on the strut?

 

[adamvanxxx]

Did you torque all the bolts with the suspension loaded?

Could possibly be the bushings binding.

 

[Justinb928]

Ive dealt with a popping noise coming from the rear of my car as I put the brakes on. I had just finished lowering my coils some before-hand and realized the popping sound was happening because the lug nuts weren't torqued enough. After tightening them down, popping noise has stopped. Might wanna check that just incase.

 

[HERBERT]

Is your coilover hitting your axel?

 

[adamvanxxx]

Is your coilover hitting your axel?

THIS TOO

 

[Datsun40146]

Well I had the car on a wheel supported alignment rack and tightened every bolt I could find under the car. Both ones that had been recently undone for the install and unrelated bolts. All were tight and were not any obvious signs of loose bolts. The end links were quite tight, they weren't going anywhere.

While I did not specifically check to see if I had coilover axle clearance I am almost sure I did. The car is not low enough to cause a problem and is using FM recommended heights.

The best suggestion I've had so far is the loose top mount. I think the Ny-locks may not be getting tight enough. I'll try and get two nuts and tighten them that way to replace the nylock nut.

I am sure the noise is not lug related. They were placed on with an impact and checked with a torque wrench.

As far as I know the springs are seated properly. The springs are in the correct position, and once settling for the 1st time should not move again. This I do not believe to the cause of the reoccurring pop.

 

[1vicissitude]

Worst case scenario I have heard of coilovers being defective or damaged that have made odd popping noises if nothing else can solve the problem. I remember reading earlier this year someone had this same issue with the fortune auto coilovers from rspeed. They were replaced and the problem disappeared. I have no idea myself what exactly would be the cause of this problem in a defective coil, only that it solved the issue for that member.

Throw the car back up in the air and check for anything rubbing really well. Check the wheels, coilover, coilover collar, axel, check the sway bars if they are binding, brakeline clearance, pretty much everything even if you think it's impossible.

Are you using the NB tophats? Are the bushings and washers assembled in the proper order?

 

[Datsun40146]

Yes, NB tophats, bushings were reassembled in the order they were taken our as per the instructions of FM. I was not alone when I installed these. We were all working on one corner at a time and we all checked what we were doing. So I doubt that its a bushing issue assembly wise.