[Musclestang4.0]

There is a stretch of road by my house that is often empty. (No cars, driveways, pedestrians, or blind spots) You can see if cars are coming from very far away, so if something were to go wrong, I would be the only one in danger. I don't speed when other people are nearby. With all that being said, when it's safe, I take my 4.0 up to some pretty sick speeds. I often get up to 100-105ish before the rear end starts to float. The steering feels very loose and sensitive, but the rear feels like it shifts from side to side slowly. I'm sure the car could go faster than that if I felt comfortable with the suspension, but I don't want to risk it. What are some mods you would recommend for the car to feel sturdy at those speeds? I have a tuner with the speed limiter off, but the only suspension mod I have is rear BMR lower control arms and relocation brackets. Thanks.

 

[Jercole0956]

I’d get both front and rear alignment checked. Most people only do the front. But it’s important to have the rear done also.

 

[90lxwhite]

Tie rods- inner and outer.
Ball joints
New shocks and struts

Go with moog for the front end stuff.

 

[rickyracer1983]

Not seeing what your car looks like, hard to say. But I do know that aerodynamics is most likely your problem. At that speed, air is getting under your car and actually lifting it up. This puts less weight on the tires and makes it "dancy". Get a front airdam/spoiler and a rear one, (not some big ugly Rice Burner wing). The front one will stop most of the air from getting under the car and lifting it up, and 100+ the rear one will start to give you down force.
How do I know, my son had a 4.0 HO, 07 Stang we did a bunch of stuff to. Once the puter was dialed in, 145 was possible on Nevada roads.
Floating usually means air issues, wandering all over the road is alignment suspension issues.

 

[90lxwhite]

Not seeing what your car looks like, hard to say. But I do know that aerodynamics is most likely your problem. At that speed, air is getting under your car and actually lifting it up. This puts less weight on the tires and makes it "dancy". Get a front airdam/spoiler and a rear one, (not some big ugly Rice Burner wing). The front one will stop most of the air from getting under the car and lifting it up, and 100+ the rear one will start to give you down force.
How do I know, my son had a 4.0 HO, 07 Stang we did a bunch of stuff to. Once the puter was dialed in, 145 was possible on Nevada roads.
Floating usually means air issues, wandering all over the road is alignment suspension issues.

Worn out shocks and struts give the bouncy float dance too. They’re 16 years old at the oldest. I’d start there first I think.

 

[rickyracer1983]

Worn out shocks and struts give the bouncy float dance too. They’re 16 years old at the oldest. I’d start there first I think.

Then it would also be "floaty" at lower speeds like 70-80. Yes they can be an issue. But funny how watching NHRA, especially, Funny Cars and Fuelers, have no shocks but aerodynamics play a big part to keep it on the track. NASCAR has proven that aerodynamics play a much bigger part on keeping it on the road at high speeds. Just a simple small piece of tape on the grill makes for down force. Look at the Salt Flats vehicles. Shocks and struts are there to control springs rates and their bounce effect.
Look at the design of a plane's wing. Flat on the bottom and curved on the top, AKA a car body. That's design is to create lift. Just looking at these 2 pictures, tells you everything you want to know.

 

[90lxwhite]

Then it would also be "floaty" at lower speeds like 70-80. Yes they can be an issue. But funny how watching NHRA, especially, Funny Cars and Fuelers, have no shocks but aerodynamics play a big part to keep it on the track. NASCAR has proven that aerodynamics play a much bigger part on keeping it on the road at high speeds. Just a simple small piece of tape on the grill makes for down force. Look at the Salt Flats vehicles. Shocks and struts are there to control springs rates and their bounce effect.
Look at the design of a plane's wing. Flat on the bottom and curved on the top, AKA a car body. That's design is to create lift. Just looking at these 2 pictures, tells you everything you want to know.

Not seeing what your car looks like, hard to say. But I do know that aerodynamics is most likely your problem. At that speed, air is getting under your car and actually lifting it up. This puts less weight on the tires and makes it "dancy". Get a front airdam/spoiler and a rear one, (not some big ugly Rice Burner wing). The front one will stop most of the air from getting under the car and lifting it up, and 100+ the rear one will start to give you down force.
How do I know, my son had a 4.0 HO, 07 Stang we did a bunch of stuff to. Once the puter was dialed in, 145 was possible on Nevada roads.
Floating usually means air issues, wandering all over the road is alignment suspension issues.

I added an aftermarket 04 Mach 1 style chin to my ‘95. I dig the looks but I’m not sure if it’s functional or not.
What about something like this in the pic for the rear? This is on an F Body, I’m trying to picture the rear of an SN95 thinking and wondering if there’s a place and a way to put a panel and if there’d be a benefit in doing so.

 

[rickyracer1983]

I added an aftermarket 04 Mach 1 style chin to my ‘95. I dig the looks but I’m not sure if it’s functional or not.
What about something like this in the pic for the rear? This is on an F Body, I’m trying to picture the rear of an SN95 thinking and wondering if there’s a place and a way to put a panel and if there’d be a benefit in doing so.

Picture C-4/F-4 could cause an air drag issue and lift. Does it enclose the forward trunk area or open toward the front? If enclosed it'll flow and not cause a drag.
The other pictures, the front and rear spoiler airdam are 90% cosmetic. The rear lets air flow under it and with no real down angle on it has no effect. The Dodge Daytona, the wing up high actually was adjustable for track speeds. 5dges can make a big difference. The front one does catch some air from going under the car, but mostly helps air flow to the radiator.
The Stang and Maverick have the type you want. They not only limit air from getting under the car, but direct it around the side. The biggest problem is you have to have them up higher then where they're really effective, for street driving. Racing you lower the front end to make the difference. The blue Zephyr I made a small 4" for the back and that helped me pick up 4MPH at 120MPH at the strip. The front smaller one helped keep the front end from lifting.
Easy example is when you drive next, put your hand out the window and use a finger as an airfoil. Moving the front or back finger will make a big difference and you the speed also.

 

[pikapp]

As some have commented, the floaty feeling, even, "rear feels like it shifts from side to side slowly", could all be from lack of adequate aero. Mustangs are inherently light in the rear and at high speeds that's amplified. You could throw a bunch of aerodynamic parts at it, but getting it just right is a lot of trial & error. To much rear downforce, not enough front downforce, etc., its all a balancing act.

 

[90lxwhite]

Picture C-4/F-4 could cause an air drag issue and lift. Does it enclose the forward trunk area or open toward the front? If enclosed it'll flow and not cause a drag.
The other pictures, the front and rear spoiler airdam are 90% cosmetic. The rear lets air flow under it and with no real down angle on it has no effect. The Dodge Daytona, the wing up high actually was adjustable for track speeds. 5dges can make a big difference. The front one does catch some air from going under the car, but mostly helps air flow to the radiator.
The Stang and Maverick have the type you want. They not only limit air from getting under the car, but direct it around the side. The biggest problem is you have to have them up higher then where they're really effective, for street driving. Racing you lower the front end to make the difference. The blue Zephyr I made a small 4" for the back and that helped me pick up 4MPH at 120MPH at the strip. The front smaller one helped keep the front end from lifting.
Easy example is when you drive next, put your hand out the window and use a finger as an airfoil. Moving the front or back finger will make a big difference and you the speed also.

The blue car is mine. The other is a random pic I found on the net of a Camaro.

 

[Musclestang4.0]

I appreciate your replies, It sounds like the issue is a mix between the suspension and the aerodynamics. Yes, the shocks/struts are the same ones from the factory with 130,000 miles on em... I'll definitely get performance shocks to fix that up. In terms of aerodynamics, I probably need to do a lot more research before I buy anything. Even a front splitter costs upwards of $400.

 

[ONEZ ST]

I would inspect the complete suspension front to back. Including your panhard bar because when that wears at the links it can cause some lateral shift in the rear even when not cornering.

You have a speed limited 4.0. Save your money and don't waste it on splitters, spoilers, wings or even a wicker bill. Focus on your suspension and steering systems.

 

[rickyracer1983]

What really is your goal here? Depending on your state 65MPH is the limit. Here in Nevada, 80-85 on the freeway. 70 on 2 lane. Or will I see you at the "Silver State Classic" race in Sept this year in the "unlimited" class? 219.6MPH is the record for the 90 mile run they do.
Don't forget, are your tires rated for the speeds you want to drive?

 

[90lxwhite]

I would inspect the complete suspension front to back. Including your panhard bar because when that wears at the links it can cause some lateral shift in the rear even when not cornering.

You have a speed limited 4.0. Save your money and don't waste it on splitters, spoilers, wings or even a wicker bill. Focus on your suspension and steering systems.

Amen.

 

[JBert]

yep I'd suggest checking all of the suspension components first; then maybe think about improved aero starting with a chin splitter

these cars are like bricks going down the road, the more air gets under the car the more it tends to lift and float

 

[90lxwhite]

these cars are like bricks going down the road, the more air gets under the car the more it tends to lift and float

However, I wouldn’t think 100 mph would require a trip to the wind tunnel for some extra tweaks by NASA engineers. I think even the late 90’s Chevy Cavalier’s would hold the road at 100 in a straight line. Heck, when I was in high school I had a GEO Tracker up to about 90 a time or two. Old suspension I bet is what he has going on like ya said.

 

[rickyracer1983]

However, I wouldn’t think 100 mph would require a trip to the wind tunnel for some extra tweaks by NASA engineers. I think even the late 90’s Chevy Cavalier’s would hold the road at 100 in a straight line. Heck, when I was in high school I had a GEO Tracker up to about 90 a time or two. Old suspension I bet is what he has going on like ya said.

Actually wind tunnels have been used by the auto makers for over 35 years now. Bill Elliott surprised everyone in 87 with his 212 MPH speed at Talladega. Come to find out, he was using Ford's wind tunnel to get air flow info for speed and down force. The manufactures wind tunnel every vehicle now, not so much for speed reasons, but also for noise they produce. Ever wonder why the little curlies on your antenna? wind noise.
Due to wind tunnel costs (usually $100K per hr) most just tape little strings all over the car and watch how they move in the air.
Air flow also is about gas mileage, easier thru the air the more mileage you get.

 

[JBert]

I wonder if there are any cool wind-tunnel videos, comparing a S197 V6 Mustang to a similarly sized brick?

 

[90lxwhite]

Actually wind tunnels have been used by the auto makers for over 35 years now. Bill Elliott surprised everyone in 87 with his 212 MPH speed at Talladega. Come to find out, he was using Ford's wind tunnel to get air flow info for speed and down force. The manufactures wind tunnel every vehicle now, not so much for speed reasons, but also for noise they produce. Ever wonder why the little curlies on your antenna? wind noise.
Due to wind tunnel costs (usually $100K per hr) most just tape little strings all over the car and watch how they move in the air.
Air flow also is about gas mileage, easier thru the air the more mileage you get.

Yeah, I know about the tunnels, I was being a little facetious. What I was getting at is that 100 mph isn’t all that “extreme” and it shouldn’t require a big investment in the aero department to be able to travel at that speed without issue. My ‘95 has a drag coefficient of something like .36. That’s nothing to write home about, (the Nissan Cube is listed at .35). But 100 mph isn’t fast enough for it to not feel stable. My half ton truck will cruise all day long at 100 mph for that matter. My Maxima on the other hand is in need of shocks/struts so it floats and bounces. But when it was new it would hold the road at 130 without being pushed around by the wind all that much.

 

[rickyracer1983]

I wonder if there are any cool wind-tunnel videos, comparing a S197 V6 Mustang to a similarly sized brick?

Probably is, just have to search for them. This is why NASCRAD is so restrictive of wind tunnel time. If you make it move slippery it means you have the same amount of power to go faster easier and safer with more down force. As simple as it may sound, this is why new vehicles don't have the old rain gutters above the doors. Wind resistance.