Quantifying the aerodynamic impact of lowering a car? (drag coefficient Cd)

[Cobb]

Ive lowered every vehicle Ive own. Sidekick, Scion XA, Insight, Geo Metro, Scion xb just to name a few. Ill buy springs or cut the stock springs. Worse to worse, cut lowering springs to get the drop you want. Nice thing if you can swing coil overs is both the shock and spring are adjustible, but you got longer payback.

I find I getupwards to 5 mo mpg and the handling is well worth it. You can curner better, steering seems crisper as well as braking.

[justme1969]

Originally Posted by 320touring

I took it as "Dry" humour

OOps my apologies truly for putting heat where it may not belong.

[320touring]

Originally Posted by justme1969

OOps my apologies truly for putting heat where it may not belong.

no worries- just arguing on the internet is a fruitless waste of time..

plenty common ground to agree upon instead

[JoL]

Just get the cheapest dampening adjustable coilovers available, keep them spun all the way up (not lowered) on a soft dampening setting, leave the helper spring and the bump stops in. They will ride very nice! And please buy a deep vr6 lip, make sure you get an oem one even if its used, the replicas shatter. I love my mklll vento jetta, i am just lowered a little with a vr lip.

Make sure you get dampening adjustable!

Please everyone do not cut springs! It ruins your strut shocks and can be dangerous.

[Cobb]

You can cut springs, oem and lowered ones. Thats ow the pros get that nice lowered look with plus size wheels and tires. In those cases for something that low you need to cut or even remove the bump stops. My tanabe springs set for my insight said to cut all but an inch off the bump stops.

Sometimes lower springs sag. My sidekick has tires 3x larger than oem and hr lowering springs. The rear is saggins and I have to add an inch spacer in the rear to level it out and stop the fenders from hitting the tires on bumps.

Since it looks like you are more interest in performance than mpg, maybe try a forum for your car?

[JoL]

Originally Posted by Cobb

You can cut springs, oem and lowered ones. Thats ow the pros get that nice lowered look with plus size wheels and tires. In those cases for something that low you need to cut or even remove the bump stops. My tanabe springs set for my insight said to cut all but an inch off the bump stops.

Sometimes lower springs sag. My sidekick has tires 3x larger than oem and hr lowering springs. The rear is saggins and I have to add an inch spacer in the rear to level it out and stop the fenders from hitting the tires on bumps.

Since it looks like you are more interest in performance than mpg, maybe try a forum for your car?

It is not a good idea to cut springs due to the fact that most have Vehicles that use progressive spring rates, I own the same chassis as the OP, which is why I chimed in on my setup.

The "Pros" don't use cut springs and level spacers, they run coilovers. Lowering isn't just for appearance it's for the sport IE handling, wheel fitment and aerodynamics.

Of course one would have to shorten the bumpstops if you run a shorter spring and strut/shock, but most strut/shocks are not made to bottom out and will break.

There is nothing wrong with leveling spacers other than they shorten your strut/shocks stroke length. I have one inch spacers on my vw on the rear since I like to carry all of my luggage and tools, as well as a full tank.

Sounds like you need to roll/modify your fenders or have taller bumpstops.

Since it looks like you are more interest in performance than mpg, maybe try a forum for your car?

I am assuming this was towards me, if I was interested in performance, I would have not bought a vw nor would have joined ecomodder.com

[Cobb]

Well, yeah, if you can get a coli over for your vehicle and afford it. Those typically come with adjustible shocks to boot. Most of us cant afford it or its not available. Tanabe was the only thing for my insight 3 years ago, unless you cut your springs. I havent seen many economy cars with progressive rate springs. Even then, you cut the coils from the tightly wound side and leave the looser coils alone.

Ive rolled my fenders, there is only an inch of less travel when the fender contacts when turning in the rear, an inch spacer will eliminate that. A good sway bar could also do it.

Ive had the bottom of my car hit the ground, but yet to blow a shock. I think they are better made like oil filters. I remember blowing cheap oil filters back in the day on VW Diesel cars.

[320touring]

Had a very productive day today:

Picked these up for £50



Boge Gas turbo dampers, with lowering springs

they're off a mk2 golf Gti 16v, but fit the mk3. Should be about a 40mm drop- sensible and comfortable!

[Cobb]

and those are progressive rate springs!!!!! They are average 200 bucks USD depending on where you buy them.

Now, disassemble them and remove the urthene bushing and cut that in half and reinstall. My tanabe instructions said to do so and it helps to reduce the whip lash effect if you bottom out, but still leaves enouugh to avoid a jarring bump if you have any ride quality issues.