Thinking out loud, large cars

[zonker]

Originally Posted by mcrews

Why suffer a worse ride, that cost you 3-400 dollars to lower, when there is 0 payback in terms of noticable mpg???

400 bux?? How about free (or close to it)! It's called wrenching in your driveway and cutting 1/2 to 1 coil off your springs.

Many cars have their ride height set to 5mph bumper collision standards rather than aero efficiency, looks, or economy. My corvette for example had a ton of shims in the rear transverse leaf for no other reason than to adjust the bumper height to match the "average" car (forget trucks, I'll slide under all of them lol).

Also, if done right, cutting the springs does not greatly increase ride harshness, but will require a reset of your toe and camber (which again can be done at home with toe plates and a carpenters level, and a correct change of spindle mounting bolts (if it's mcphereson strut you're working with).

[mystere485]

Im not sure if im brave enough to cut the spring, wouldnt it leave it without a level seating base?

How true is this information?
Cutting Springs - Craig's Website at Backfire.ca

I guess my main concern is the spring popping out, I cant...I can think of one time I jumped my moms minivan over the railroad tracks and it bottomed out the suspension. Otherwise it would have to be pretty bad shocks or exceptionally fast over speed bumps to bottom out.

Theres enough crown vics around for parts that id give it a try. They are only $20ea at the local PYP.

[mystere485]

Originally Posted by zonker

8.8" carrier, 3.08:1 ratio, non limited-slip.
The next taller diff gear available is 2.73's, or the equivalent of changing your tires to a 30" diameter.

Is "Y" the standard letter for this rear end? There is a grand marquis in the pyp near the same vintage that I was going to check out tomorrow.

[zonker]

Originally Posted by mystere485

Is "Y" the standard letter for this rear end? There is a grand marquis in the pyp near the same vintage that I was going to check out tomorrow.

for the year 1994, Y is 3.08... that I know. It could be mustang, crown vic, or any similar rwd mercury of the same vintage - doesn't matter.

[zonker]

Originally Posted by mystere485

How true is this information?
Cutting Springs - Craig's Website at Backfire.ca
.

i did a brief glance over and the points he makes are valid, but severely overstated. if you do the job in a conservative fashion you will have no such issue.

The trick to it is making sure you cut from the side with the coils closer together, and cut off only an amount that leaves the remaining spring to sit close to the uncut version did in it's perch.

We're not talking about making huge cuts here, just enough to bring ride height down a little.

as for bottoming out, make sure you have bump stops that are in working order to prevent from damaging the shocks.

also, once the springs are in their place, there should be a small amount of preload still holding the springs in their perches.

If you lift the car and the springs will move out of their perch seats, then thats when you've cut too much - and then will have a safety problem like the doomsayer craig says..

[instarx]

Originally Posted by Arragonis

That combined with the fact they do about 130 flat out and the standard UK motorway police traffic car was a Volvo T-5 or a T5R with a top speed of 150+ made us giggle more.

There are some great videos of European Police Volvo T5 station wagons effortlessly keeping up with Porsches and Ferraris at 230 kph on YouTube. The T5s police wagons can reach over 155 mph. Ordinary production T5s are governed to a measly 140 mph. It's little known, but in the late 90's the Volvo T5 5-cylinder wagon was the fastest production car in the world. This is the same grocery-getter that soccer-moms got better than 30 mpg with.

[NHRABill]

WOW what a thread ... so much info don't know where to start?

1st off good luck on the crown vic good durable car that can take a beating..

On that note you are a fool to cut your coil springs there are dozens of reasons I say that but mainly its because your ride will suck because the spring has everything to do with its rating and little to do with its height.

back int he 70's if you wanted to lower a car take a torch t o the spring heat it till itglows throw a few frinds on that side of the car and voila you have a low rider with zero suspension. aerodynamics from this Umm no ...

If you want to lower your car put it on airbags and save weight but be ready to shell out a lot of cash. How do I know this? if you have any practical auto knowledge or moron friends that you warned a dozen times that still do it then.... well you know... or f you like to race cars and want the tires to hook up you learn fast how to triangulate your suspension and how adjustable drag shocks and progressive springs are a godsend.

Tires whis on the Vic i would go with a 235 in the front and a 245 out back using a 70 series sidewall to retain a close to stock ride height but less meat on the road but enough to be safe. I rad 215/60/15 on my vette and even 195 65 15 on a firebird on my street strip cars a while back and they are terrible and unsafe on the street when you have 3200lbs or more rwd car.. 235 seemed just right in handling.

As far as mods I would try and lower your airdam a inch or 2 but would first find a speedbump on an empty road or parking lot and measure the height you have to play with before you do so. also note curb height when pulling straight in how far forward it is and so on...

Shed some weight from the car lose the spare and keep the engine purring smooth most people overlook buying a new coil and in my opinion it is a must replace every 100,000 miles i need to put a new one on my truck lousy weather keeping me from working on it.

Good luck

[Frank Lee]

I've cut my springs and I'm happy with the results.

Did it gain aero and fe? I don't know. If so, it's very small.

Did it ruin the ride? No. It's definitely is harsher on big bumps- after all I took away about 40% of the compression travel. It gained a lot of stability in cornering.

For a while I ran a bigger sway bar in front too. I switched back to stock because with the lowered height the stability was so improved, that the bigger bar wasn't really helping- all it did was add a little unnecessary harshness.

On the back the springs aren't long enough to stay preloaded when the car is jacked up off the ground. So I suppose it's possible for the spring to unseat if I ever get the car airborne. I don't even know how many years ago I cut those springs, but it hasn't been an issue.

I did re-shape the last coil after cutting so it would sit nice and square in the seat. I used as little heat as I could while squishing it in a vise. No problems.

I cut 1 3/4 coils off the front and 1 coil off the back with a chop saw.

[zonker]

Originally Posted by NHRABill

WOW what a thread ... so much info don't know where to start?

1st off good luck on the crown vic good durable car that can take a beating..

On that note you are a fool to cut your coil springs there are dozens of reasons I say that but mainly its because your ride will suck because the spring has everything to do with its rating and little to do with its height.

back int he 70's if you wanted to lower a car take a torch t o the spring heat it till itglows throw a few frinds on that side of the car and voila you have a low rider with zero suspension. aerodynamics from this Umm no ...

If you want to lower your car put it on airbags and save weight but be ready to shell out a lot of cash. How do I know this? if you have any practical auto knowledge or moron friends that you warned a dozen times that still do it then.... well you know... or f you like to race cars and want the tires to hook up you learn fast how to triangulate your suspension and how adjustable drag shocks and progressive springs are a godsend.

"well I know" never to torch a spring, and airbags make a car handle like the car needs to be arrested for a DUI.
Removing 1 coil or less will lower the car maybe an inch, and increase harshness less than a set of aftermarket lowering springs.

Originally Posted by NHRABill

Tires whis on the Vic i would go with a 235 in the front and a 245 out back using a 70 series sidewall to retain a close to stock ride height but less meat on the road but enough to be safe. I rad 215/60/15 on my vette and even 195 65 15 on a firebird on my street strip cars a while back and they are terrible and unsafe on the street when you have 3200lbs or more rwd car.. 235 seemed just right in handling.

215 is the oem size, so unless all oem base model crown vics are unsafe, I hardly think he's going to have a problem with a tire in a similar width.

[mcrews]

Originally Posted by mystere485

245/45/18 to 255/45/18 changes the width not the height
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
REALLY!!!!!!
WOW,
and to think I've been telling everybody the wrong thing for 4 years, 180,000 miles and 4 sets of tires!!!

oh.........btw....................you're just a little bit wrong.

Since 245 is the stock factory tire and 255 the tire I run.....oh and you can read any of my posts and see that I only refer to the advantage of ther one size up tire EVERY time as a key reason for my mpg.
AND I have used a Garmin 360 Nuvi to acuratly calculate my miles on long trips to ACCURATELY document the REAL miles and TRUE MPG

BUT here is the chart from TIRERACK.com on the Kumho's that I run.....

size 245/45ZR18 255/45/18
max psi 50 psi 51psi
tread depth 11/32" 10/32
weight 30lbs. 30lbs
rims 7.5-9" 8-9.5
overall width 9.6" 10.1
tread width 9" 9.3
diameter 26.7" 27”
rev per mile 778 769
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"Active ride height that lowers the vehicle at speed, which Ford employed on the Lincoln Mark VIII and which appears on Mercedes-Benz vehicles with Airmatic suspensions. According to Mercedes, "Lowering the ride height at speed results in a 3-percent improvement in drag." Car Aerodynamics 101

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I didn't know he was buying a Mark VII??????
Or a Mercedes???????

Let's stick to the topic. 1994 crown vic. Not a BRAND NEW car with active suspension being tested.

1. the 1994 is probably already 1/2 inch lower than new factory. So the point becomes moot.
2. But before you have him reuild the front rubber, you want him to lower it.
3. Since I was talking about HIS EXACT RIDE and not some $10k active suspension that he can't get and has NO bearing on the disscussion, I'll stand by my points.

__________________________________________________ ______________


I understand that; anti-roll bars, shock rates, and camber adjustments should be taken into account when modifying springs as well.



Because of the saggy springs no doubt!



A front air dam and belly pan is in the plans.

Fud2468, sorry for hijacking your thread.

When the day is over, ABA testing on the crown vic w/ one size up on the tires WILL show and improvement in mpg. period.
The 'lowering and crapping" of the suspension may or may not.
But he will be stuck with the altered ride.

THe facts are very simple when done apple to apple.