suspension mods

[mustang gt s]

here is a list of suspension mods I want to do to my 03 cobra vert.
what do you guys think?
mm subframe connectors
ftbr irs bushing kit
mm coilovers, shocks, struts, cc plates
mm springs f 325 r 500
mm steering rack
front bushings
diff. cover
tower brace
brake lines

 

[2DXTRM]

Good setup.

Which brand/series struts and shocks are you going to use from MM?

 

[snakeraper11b]

Only thing I would stress is the MM sport series bilsteins and bumping the rates up to 375 front and 600 rear.

 

[shurur]

FTBR IRS all
MM subframe
MM AL rack bushings
MM solid steering shaft

And if you are going to stay with stock k-member and front A-Arms ..look at MM 4 point k-member brace or stifflers brace and GW/MM Delrin bushings for stock A-Arms...and new ball-joints while you're in their.


But I'm guessing you are planning on MM k-member and MM control arms "later."

Also level your swaybay once you settle on your k-member/a-arm choice.

Bump-steer can wait...or not..

Some CO folks are going

Street F: 430-455 R: 470-495
Race: F: 480 R: 520

Q: Did MM recommend those spring rates?

 

[Tractionless1]

I have no idea unless you specify what your plans are for the car.

 

[mustang gt s]

Good setup.

Which brand/series struts and shocks are you going to use from MM?[/QUOTE

bilstein hd

 

[mustang gt s]

Only thing I would stress is the MM sport series bilsteins and bumping the rates up to 375 front and 600 rear.

well one of the reps of mm said 325 and 500 would be what to get as far as spring rates.

 

[mustang gt s]

FTBR IRS all
MM subframe
MM AL rack bushings
MM solid steering shaft

And if you are going to stay with stock k-member and front A-Arms ..look at MM 4 point k-member brace or stifflers brace and GW/MM Delrin bushings for stock A-Arms...and new ball-joints while you're in their.


But I'm guessing you are planning on MM k-member and MM control arms "later."

Also level your swaybay once you settle on your k-member/a-arm choice.

Bump-steer can wait...or not..

Some CO folks are going

Street F: 430-455 R: 470-495
Race: F: 480 R: 520

Q: Did MM recommend those spring rates?

yes they did for street set up.

 

[mustang gt s]

I have no idea unless you specify what your plans are for the car.

car is a weekend driver,street car maybe a track or two and hit the twistys.

 

[snakeraper11b]

FTBR IRS all

Some CO folks are going

Street F: 430-455 R: 470-495
Race: F: 480 R: 520

Those are way high in the front for the rear rates.

Good setup.

Which brand/series struts and shocks are you going to use from MM?[/QUOTE

bilstein hd

well one of the reps of mm said 325 and 500 would be what to get as far as spring rates.

Those spring rates are maxed out on the bilstein HD's, that's why. If you run more spring, it'll ill the dampers. If you bump up to Sports, then you can run the 375/600 combo.

 

[shurur]

Yes..if you are going CO, I wouldn't waste $ fooling with stock bilstein HD rates...as snakeraper11b has said.
I'd call MM again about the MM sport struts/shocks and your desire to maybe track it.

Also if you plan to stay stock K-member, You should look at doing the motor and transmission mpounts as well.

I'm not sure if the mounts transfer to a MM k-member for a later swap from OEM or not though..snakeraper11b has MM kmember?? He may know offhand.

 

[shurur]

Those are way high in the front for the rear rates.

Maybe you're are right, but as I understand it..too much spring in the back compared to the front gives you push into the corners and understeer...while a more matched setup does not and can even a bit of oversteer...especially if the rears are "slightly progressive,"..(for lack of a better way to put it.)

It's a driving style thing I think.

I think that Bruce at FTBR has his almost matched at 500 front and rear. And he races..

but I'm more familiar with the Newedge and it is better balanced.

Having said that and considering the car we are discussing, the terminator is a nose heavy beast..so more spring in the back would have the effect of balancing it out..so for the terminator what you say is probably true after all.


Me:
I'm guessing I'll go CO and MM "someday."

I just had to decide when My suspension/handling mods were "done;" so that I could finally pursue more HP.
I still need Solid diffy mounts (which I have..MM), solid rear toe-bars and a solid steering shaft...I also like the Eibach Swaybay...for someday..

I like threads like this and to see folks doing the suspension/handling mods first.

 

[snakeraper11b]

Those are way high in the front for the rear rates.

Maybe you're are right, but as I understand it..too much spring in the back compared to the front gives you push into the corners and understeer...while a more matched setup does not and can even a bit of oversteer...especially if the rears are "slightly progressive,"..(for lack of a better way to put it.)

It's a driving style thing I think.

I think that Bruce at FTBR has his almost matched at 500 front and rear. And he races..

but I'm more familiar with the Newedge and it is better balanced.

Having said that and considering the car we are discussing, the terminator is a nose heavy beast..so more spring in the back would have the effect of balancing it out..so for the terminator what you say is probably true after all.

I'm sorry I had to LOL. It has nothing to do with balance. It has to do with the SRA VS IRS if you want to compare a newedge vs an SN95. First of all the rates are offset like that due to the different wheel rates of the front vs the rear. The front ratio is a .9 and the rear is .6. So the 375#front spring results in a wheel rate of 337.5#. The rear results in a 360# wheel rate. I would also guess a full prepped track car runs more than a #500 rear spring, seeing as how that is recommended for for stock bilsteins.

 

[wheelhopper]

OP, I ran through the list of posts and I did not see your intended use for the car. Maybe I missed it. Don't follow the spring recommendations of shurur. He does not know what he is talking about. Not being rude just a fact. I would also bet money that Bruce does not run a 500/500 spring rate on any of his coilover IRS cars.

While I am not an expert I have been running IRS cars on the street for 10 years and road course for 6. Here are my recommendations

If you are going to be mostly a street/drag race driver I would not even worry about having coil overs. They are nice but not worth the money IMO. I would go with a H&R SS if you are more inclined to drag and Race if you are more into handling. Both will work with your stock struts and shocks. If you need new ones get the Bilstein Sports.

If you insist on coil overs then I would do a 325 front and 475 rear. This is a nice street combo that will hook well at the drag strip and handle better than stock on the street.

If you are looking for more of a street/road course/autox set up with your coilovers then I would do 375 front/575 rear. You can use push the envelope with your stock dampers but the Bilstein Sports would be better.

FYI. Just recently there was a guy on Corral that was selling a set of Sports for around $500 that were in good shape.

 

[cobracide]

Sticking with a stock type stock setup - 200-300in. Front, 650-800#/in. Rear.

Steeda Sports and H&R Race fall into here nicely, MM Sport shocks/struts are a more aggressive pick over the stock Bilstein HDs. Bought my Sports from MM with their valving. Bilstein Sports are also much stronger than the HD due to the reinforced ears over the HDs. One major difference between the H&R and the Steeda is that the Steedas are progressive in the front and back where as the H&Rs are only progressive in the front. The spring rates are also slightly different, refer to the spring rate stick at the top of this forum.

 

[shurur]

I'm sorry I had to LOL. It has nothing to do with balance. It has to do with the SRA VS IRS if you want to compare a newedge vs an SN95. First of all the rates are offset like that due to the different wheel rates of the front vs the rear. The front ratio is a .9 and the rear is .6. So the 375#front spring results in a wheel rate of 337.5#. The rear results in a 360# wheel rate. I would also guess a full prepped track car runs more than a #500 rear spring, seeing as how that is recommended for for stock bilsteins.

The SRA has nothing to do with this discussion and weight distribution front to rear has very much to do with the CO spring rate you choose. The .9 front and .6 sounds interesting.

 

[shurur]

OP, I ran through the list of posts and I did not see your intended use for the car. Maybe I missed it. Don't follow the spring recommendations of shurur. He does not know what he is talking about. Not being rude just a fact. I would also bet money that Bruce does not run a 500/500 spring rate on any of his coilover IRS cars.

Never said I was an expert. But do look on this forum to glean all the info I can. for the record, I didn't recommend anything.

I think we need FTBR to chime in here.

I still seem that this whole CO gets murky..and too seems to depend on preference in how the car handle. .......

 

[snakeraper11b]

The SRA has nothing to do with this discussion and weight distribution front to rear has very much to do with the CO spring rate you choose. The .9 front and .6 sounds interesting.

Read up on linkage ratios and wheel rates, then get back to me about the solid axle not mattering when it comes to the spring rate.

 

[shurur]

Read up on linkage ratios and wheel rates, then get back to me about the solid axle not mattering when it comes to the spring rate.

I'm saying the SRA is not part of this discussion...and a totally different geometry. I assume OP has IRS since he is going FTBR...so any discussion about the SRA is a Stawman.

I think mainly we are just misunderstanding each other..

I know the stock springs non CO effective rate is 1/4 front and ~1/3 rear for the IRS and has to be taken into account...but also so does the F/R weight ratio play into the ratio between the springs front to rear. As I understand it, it has to do with the pivot point of the car around corners and is most important in cars that have less than desirable F/R weight ratios.

Then there is the tire width F/R which we'll leave alone.

I also know that the CO on the front is .9 of the chosen spring rate..I have not seen anything about the .6 for the Rear CO. The shock/CO mount is a bit further away from the spindle on the rear as compared to the front; so that could be. And the angle of the shock /strut will play into the normal force.

I'm interested in the IRS rear .6 CO effective weight ratio you mentioned ..is this in the MM site??

 

[wheelhopper]

Never said I was an expert. But do look on this forum to glean all the info I can. for the record, I didn't recommend anything.

I think we need FTBR to chime in here.

I still seem that this whole CO gets murky..and too seems to depend on preference in how the car handle. .......

I never accused you of being an expert and if the info you have gained from this or any other forum has enlightened you to recommend the spring rates you previously posted you need to look further. I have spent a lot of time researching and trying different spring rates for my IRS equipped mustang, that I race in TT, and never have I seen an odd combo like you recommended. I am sure you have the best intentions, but your info is just wrong. And for the record here is the exact rates you recommended
"Street F: 430-455 R: 470-495
Race: F: 480 R: 520"

Send Bruce a PM and ask him what he runs. I am sure he would tell you.

There is nothing murky about using coil overs. The best handling situation to have is a neutral handling car, unless you are wanting to drift. Then over steer is ideal. Usually once you have a good spring combo you fine tune over and under steer with the sway bars.

There are several good books out there that detail suspension set up and handling
Amazon.com: How to Make Your Car Handle (9780912656465): Fred Puhn: Books

OP, if all this is making you feel a little confused go with MM recommendations.