Changing standing ride height

[raptoranderson]

After fitting an aftermarket exhaust muffler and back-box, the exhaust has a tendency to scrape on the road when going over speed-bumps with any sort of weight in the back of the car in excess of 40kg or so. I was looking at a Koni suspension kit which would lower the car by at least 30mm, but this will more than likely cause the exhaust to hang even lower.

I've raised the muffler all the way up to the bumper of the car so I can't possibly raise it any higher without cutting into the bodywork. Would it be a case of tuning the suspension so that the ride height did not drop when under load, or would I need to consider using bigger wheels to give the car more clearance (current 15" wheels)? Or would I have to do something else entirely? Suggestions anyone??

 

[skymera]

Got any pics?

Mine's never hit the road.

 

[Skinner_87]

After fitting an aftermarket exhaust muffler and back-box, the exhaust has a tendency to scrape on the road when going over speed-bumps with any sort of weight in the back of the car in excess of 40kg or so. I was looking at a Koni suspension kit which would lower the car by at least 30mm, but this will more than likely cause the exhaust to hang even lower.

I've raised the muffler all the way up to the bumper of the car so I can't possibly raise it any higher without cutting into the bodywork. Would it be a case of tuning the suspension so that the ride height did not drop when under load, or would I need to consider using bigger wheels to give the car more clearance (current 15" wheels)? Or would I have to do something else entirely? Suggestions anyone??

Lowering springs are normally stiffer RA so may help but as you say they will lower the car but may be uprated enough to cope.

Which speed bumps are you going over?? my Astra was quite low but never had any problems?

 

[skymera]

Do'h K12 section.
Still, upload a pic of the box and how it's sitting.

 

[Enuo]

Check that the saddle bracket that goes on the second cat that attaches to the body with exhaust rubbers isn't rusted through and broken, as this will cause it to scrape all the time...

 

[raptoranderson]

It's just the muffler that scrapes on the ground, everything else is fine. It's only because its aftermarket that it hangs rather low, and because it comes out of the centre rather than on the standard left-hand side, I've drilled a hole through the bottom of the spare wheel well and put a bolt through a bracket that attaches the muffler to the rubber bung. It's only when there's someone or something heavy in the back of the car that it scrapes, and its only on the speedbumps that are along the driveway into the campus grounds. I'm only considering this problem because if a body kit were to be fitted onto the car, the rear bumper would undoubtedly be lower than the exhaust muffler and it would scrape on the bumps instead of the exhaust. The muffler is here on the car (the standard muffler is in green, the aftermarket in red):

 

[raptoranderson]

I'll go out and take a proper picture of the exhaust later bu that's pretty much where it is at the moment

 

[skymera]

It goes out the middle...

It wasn't designed to go there which is why you're having problems.
I doubt there's much you could do other than try to pull it up as much as you can.

And did you say bodykit?

 

[raptoranderson]

Yeah, it goes out the middle .... I was just as confused as you were when I took it out of the box and held it up under the car. And the body kit would just be a front and rear bumper and sideskirts, should the bodywork specialist I know accept the challenge that is ....

 

[h701micra]

You'll need stiffer springs or longer springs.

Lowering springs aren't any stiffer over standard unless they are decent premium springs.
A coilover kit would be your perfect solution and as professional advice, the only solution

 

[drand]

True enough but not many people fit coilovers to _raise_ the ride height, especially for the sake of an exhaust. It would compromise the whole car imo.



If you wanted centre exit you could modify a back box in the standard pace to bring the exit into the centre, then there's only the diameter of the pipe to worry about.

 

[h701micra]

True enough but not many people fit coilovers to _raise_ the ride height, especially for the sake of an exhaust. It would compromise the whole car imo

In what way would it compromise it?

Also we wouldn't be raising the car just stiffening it up in its current height

 

[drand]

Higher cg was what I was getting at, also it's a 160 , would look wrong on stilts.

 

[h701micra]

Higher cg was what I was getting at, also it's a 160 , would look wrong on stilts.

CoG wouldn't change

Many cars look good on "stilts"

 

[skymera]

Higher cg was what I was getting at, also it's a 160 , would look wrong on stilts.

What does the 160 mean? 1.6?

 

[h701micra]

What does the 160 mean? 1.6?

K12 160SR?

 

[skymera]

K12 160SR?

Yus, just Googled and fell about laughing.

 

[raptoranderson]

It's not actually a 160, thats just the picture i used ..... i'll go take a picture for y'all now

 

[raptoranderson]

In order:
1.) My car (duh)
2.) Rear wheel ride height
3.) Exhaust muffler
4.) Exhaust muffler
5.) Front wheel ride height

 

[skymera]

Holy mother of **** balls.

Those wheels, dat height.

Zorst like a penis poking out of a jean zipper.

I can't see how that is scraping the floor. It's a mile from it to start with and the box doesn't look that big.

You sure it isn't hitting the bodywork somewhere?

Can't see for sure, but what is that bar going across the top of the exhaust? Maybe that is hitting when loaded up?

 

[raptoranderson]

I know, its perverse! D: hahaha I'm looking at 17" wheels to make the height seem less drastic and to raise the car off the ground a bit, but that's why im asking about a suspension system because it will unlikely lower the car too far and the wheels will scrape on the wheel arches ....

And i'm pretty sure it's just the muffler scraping on the ground when the front wheels have gone over the bump but the back wheels are yet to do so. But if i had to have the wildest of guesses as to why it happened, id claim that the rear suspension was either tuned wrongly or shot ....

The bar is more than likely reflection of the flash on the bumper, if not then its probably part of the chassis, but thats definitely not what's hitting the ground. Seriously though, having weight in the back of the car causes it to lower a stupid amount and it can't be normal

 

[skymera]

Get some daylight photos tomorrow and upload them

Got a link to what you bought?

 

[raptoranderson]

Will do

And are you talking exhaust muffler?

 

[raptoranderson]

In order:
1.) Ride height
2.) Exhaust muffler
3.) Backbox on the left and muffler
4.) Rear ride height
5.) Front ride height

Current space between wheel arch and tyre is about 3.5 inches and the ride height probably gives one an extra 1.5 inches before the car starts to scrape on the ground.

 

[h701micra]

Obvious question coming up....
Aby scrape marks on the exhaust? Or anything under the car.... that's the only way to see what is, if anything, hitting the floor

 

[raptoranderson]

Not so obvious answer coming up ...
I haven't the faintest idea hahaha

 

[raptoranderson]

There are notable scrapes on the end of the muffler, which leads me to conclude that the muffler may well back too far BACK on the car rather than too low .... and come to think of it, the exhaust clamp which I had to use did end up pushing the exhaust towards the back of the car an inch or so because the clamp was too long for the section of the pipe which had been shrunk for attachment ...

 

[h701micra]

Grind it off

 

[raptoranderson]

That's what I'll get round to doing eventually .....

Now, adjusting ride height by using bigger wheels: any potential problems? I've done the math and the measuring with the old wheels and I've added a couple of inches to check the clearance from the wheel arch with the new wheels and it looks fine. Will this actually make a difference to ride height or not?

 

[h701micra]

Slower acceleration
Speedo will read slower than actual speed

 

[raptoranderson]

Speedometer does that already -.- hahaha but youve got true speed and then engine speed and all that jazz so .....
How noticeable will the acceleration difference be do you reckon?

 

[h701micra]

Depends how big the wheel size difference is and the wheel weight

 

[raptoranderson]

Can anyone recommend any decent coilovers for a Nissan Micra K12? I've emailed Gaz and am awaiting a response from them, but in the meantime i feel sure that a renault clio coilover kit might fit a Micra because the chassis is the same ....?

 

[h701micra]

Go scrapyard and measure em