hazard of aerodynamics.... (low ride height = bumper damage)
 

I have an Infiniti Q45 Sport w/ A full IMPUL body kit. It lowers the body 2 inches all the way around.
I also (just 8 months ago) installed spring compressors on the front and dropped the front 1.25inches..
The front edge of the bumper is 5" off the ground.
Last week I was on a side street I've never been on and hit a dip in the road at about 25-30mph. It wasnt maked and I was looking at my gps.

The front edge of the bumper hit square.
THe worst part is that I had just repaired some dings in the bumper over the holiday.
The 'cracks' are were the repairs were.
http://i678.photobucket.com/albums/v...5/IMG_2525.jpg

http://i678.photobucket.com/albums/v...5/IMG_2524.jpg

http://i678.photobucket.com/albums/v...5/IMG_2522.jpg

That's a bummer.

Low ride height is definitely a concern (though 5 inches doesn't sound terribly low!).

Makes me wonder how common this kind of thing is with supercar drivers (think: Ferarri... Lambo).

My wife's last car was a PT Cruiser. The chin spoiler was exactly five inches off the ground. Completely stock.

THe 5" measurement is 39" from the frnt axle.
My gut feeling is there is 'some' relationship to how far uot the front edge is and how much space is 'allowed.'

this picture was posted 2 yrs ago when I had a question on this forum.
over 7" factory stock w/IMPUL body kit.

http://i678.photobucket.com/albums/v.../mpgq45128.jpg

You are correct in the relationship to ride height and bumper length. My Sentra could get away with a shorter front end, because it is so close to the tire, my old truck however, would scrap on the street if I didn't come out of the driveway just right. Don't let it discourage you though, a little epoxy, some clamps, and a lot of patience and you will never know it happened.

Yikes! Sorry to hear that. :(

Wow, that sucks... Caution is advised! :eek:

FYI: Approach angles for several models of the Porsche 911 for reference.

GT3 ground clearance - 6speedonline.com Forums
http://i257.photobucket.com/albums/h...e/scan0004.jpg

5.5 to 11.8 degrees

sports cars can get away with lower ride height because they use stiffer springs, which give them less wheel travel.

you lowered the ride height with STOCK springs, with full range of motion in bump. ditch the spring compressors and buy proper springs.

Excellent point.

I just looked up what that car looks like, not a variant of the Z-car.

(But you saw a complete side view when you responded to the thread about a kammback on it several weeks ago......)

no....it's the car in the avitar.


I purchased swift springs several yrs ago.(aftermarket lowering springs) desighned for that exact model.
Rear constantly bottomed out and the ride was terrible. I removed the rear and keep the fronts(briefly) I then removed the fronts. and the stock psrings relpaced.
Last year I recieved a slightly used rear set of springs from an 2007 M45 and installed those. They lowered the rear about 1/2 inch and saw no noticeble change in ride quality.
The compressors were installed to test the theroy that a better angle on the front would improve mileage. Which they did. And the ride is much better than with the swift spring kit.

Inboard air dam locations
 

Having owned lowered vehicles with aftermarket dams, I could relate with the misadventures. Entrance ramps, speed bumps, sudden spring potholes, expressway dips, drainage intersections, etc to name just a few choice locations. The vehicles' shallower entrance angles are always a bich. I've always appreciated the Corvette engineers solution to locate their deepest & ablative center air dams more inboard (feeding big mouth radiators) to mitigate road damage, yet still able to direct less air underneath. Here is an aftermarket solution (the round inlets allow brake cooling). https://www.southerncarparts.com/ima...-Air-Dam-1.jpg

wow.:eek:.....where were you 5 yrs ago??!!!!:rolleyes:

that is very slick:thumbup:

Normally I would agree with you, but we are not talking about some little Honda or Toyota. It is noted with most luxury cars, such as yours, that the lowering springs are not as stiff as the stock springs. And the spring clamps, so long as checked on a regular basis, are plenty safe for use. The mishaps/horror stories on the internet are from people who install them and never do the follow on torque checks or periodic checking. I am not trying to start an argument, just posting a point.

i have know several Q45 who used lowering springs (swift is the only mfg for the F50) and then removed them.
Since the Sport model has the electronic suspension I wont/cant use the coilover kits that are a more common method of lowering.

16-degrees
 

Ouch!
The SAE recommends a 16-degree approach clearance with 300 lbs of ballast on board.Curbs,gutters,and driveway ramps are supposed to be constructed such that automobiles will always 'clear' if built to the SAE minimum.
Supercars can cheat,as they have active suspension,lowering the car only when it's out of harm's way.;)

Sucks. Have you thought about taking the body kit off and constructing a Corvette style air dam?

I dont have the original bumper any more.
I can fix this actually.

The broken spots on each side had broken over the last yr and I fiberglassed from the rear over Jan.
I had already put on a coat of paint on the driver side and was sanding the last coat of primer on the passenger side.

Here is a pic of the finished work right before the last dark coat of primer.

http://i678.photobucket.com/albums/v...t/IMG_2426.jpg

http://i678.photobucket.com/albums/v...t/IMG_2425.jpg

All I saw was these extreme close ups you posted, I had to do a Google image search to get the "big picture". I'm not going to remember things from two weeks ago, I'm too old for that. I also don't know all the Asian car models using numbers because I have no interest in them, they don't do a thing for me.

Great information, I'll file this one in my memory banks - SWEET 16.

got it.....:thumbup:

5" over 39" is a 7.4 degree angle. :eek:

5/39 = 0.128
sin (7.4) = 0.129

:(

And that is why i didn't lower my Camaro, and i'm not going to lower my truck

Great info, I'm going to make some measurements tomorrow!

You just found out why I use ugly, expensive, hard-to-fabricate, indestructible conveyor belting for my air dam.

the cost of replacing the IMPUL front bumper is around $1800.
The IMPUL product is a Japan Domestic Market product(jdm) and has to be crated and shipped from Japan. There are probably only 10-15 full body kits installed in the USA. (i was the 4th in 2005).
I decided to repair it and live with the inperfections. Afterall, I have 255,000 miles on the car and will always keep it since the resale is nil. it still runs great and just last week got a compliment on the ride quality. (again)

Here is the current state of the body work:
http://i678.photobucket.com/albums/v...t/IMG_2556.jpg

first coat of primer

http://i678.photobucket.com/albums/v...0321-00014.jpg

http://i678.photobucket.com/albums/v...0321-00015.jpg

Looks good! Can't wait to see it painted.

Good recovery, got to be a jack of all trades in this game eh?

yes, absolutely!

I wish all bumpers were made out of foamed urethane. That stuff always bounces back.

Pool noodles will be back on store shelves soon. I suggest trying the Dollar Store first.

A proximity sensor mounted on the front air dam might help when parking.

I had the same idea several yrs ago.....couldnt figure out how to keep the range short enough to just work when parking

...or a front mounted camera! ;)

Speaking of pool noodles, do they come round and smooth sided, not scalloped or fluted?

They or huge polyethylene pipe insulators would make great wheel fairings, cut on a diagonal.

They used to only come as smooth, most places around here still carry them that way. Getting the larger diameter ones has always been a challenge, Toy's-R-Us used to carry a variety. K-Mart and Wallmart carry them too. The dollar store just has them cheaper, but rarely in the larger diameter.

Check hardware or building supply outlets for foam pipe insulation.

The manufacturers of proximity switches may be able to spec. the right range for you.

I was looking at a discounted back up sensor kit that was clearance at the autoparts store.

Curb feelers out the front? It'll look like a catfish. :p