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wheelhopper

Looking for suspension info from the pros

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wheelhopper

I run a '90 GT in TT and am trying to maximize my suspension. I run TTD and without trying I have found my car is set up similiar to a CMC Mustang. A big difference is that I am running an IRS. What are the popular springs/rates to run on the front. What struts and shocks do you guys recomend.

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wheelhopper

Nobody wants to reveal any secrets huh?

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ShadowBolt
Nobody wants to reveal any secrets huh?

 

No Secrets. Most of us in Texas run around 900/225 but we don't have the IRS so I don't know how much that will help you. Most of us run a PM3L (poor man's three link). Again with your IRS no useful information.

 

 

JJ

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D Algozine

I used to race a 95 Mustang, which is nearly identical platform to the Fox. I had an IRS with all of Maximum Motorsports suspension parts, front and rear, ie. Kmember, contral arms. There entire front set up and all of there parts for the IRS.

 

Front

Coilovers

Race valved Bilsteins - MM race settings

425 lb spring

Smaller 27mm bar

Camber - 3.2 to 3.5

Caster Full positive, should be + 6 to 7

Toe 1/16†toe out

 

Rear - 2003 IRS

Coilovers

Race valved Bilsteins - MM

475lb spring

stock IRS rear bar

Camber - 1.5

Toe 1/8†toe in

 

Contact me directly or contact Maximum Motorsports for more info.

david at algozine dot com

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wheelhopper

 

No Secrets. Most of us in Texas run around 900/225 but we don't have the IRS so I don't know how much that will help you. Most of us run a PM3L (poor man's three link). Again with your IRS no useful information.

 

 

JJ

 

I know that your straight axle rates won't help me with the IRS rates, but by getting an idea of what is working for you guys on the front I can match the rear rates to the front rates. With the info that you're running 900lb front springs, I can tell that I am definitely undersprung on the front, especially if your springs are a linear rate and not progressive.

 

What type of struts and shocks did you prefer? I tried the Koni DA and had a really hard time trying to dial them in. I added 3 seconds onto my lap times with them. I switched them out for my Edelbrock struts and shocks, that I had before I started OT, and the times dropped back down.

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wheelhopper

Thanks for the info Dave.

 

Another post that leads me to believe my H&R race springs are not stiff enough. Good thing I have a set of Super Race in the garage and ready to go. I know the Konis I have will handle the Super Race spring rate, if I can just get them adjusted right. Anyone have a good baseline for me to set them at to get started. I have tried calling MM and others in the past and they are not really helpfull in that regard. Keep in mind I am a budget racer and don't have a lot of track time available to have the dampers at a setting, take a few laps, come in and adjust, then go back out and do it all over again until it is right. A little head start would be greatly appreciated.

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D Algozine
Thanks for the info Dave.

 

Another post that leads me to believe my H&R race springs are not stiff enough. Good thing I have a set of Super Race in the garage and ready to go. I know the Konis I have will handle the Super Race spring rate, if I can just get them adjusted right. Anyone have a good baseline for me to set them at to get started. I have tried calling MM and others in the past and they are not really helpfull in that regard. Keep in mind I am a budget racer and don't have a lot of track time available to have the dampers at a setting, take a few laps, come in and adjust, then go back out and do it all over again until it is right. A little head start would be greatly appreciated.

 

There are far too many variables to give you a starting point for the Koni's. Somewhere on the internet is a complete write up on how to adjust your shocks. Check out this link http://www.koniracing.com/rrtuningguide.cfm Its a step by step process.

I originally started with Koni DA's, and never felt comfortable with the adjustements. Then I switched to race valved Bilstein. I highly recommend the Bilsteins.

I don't know the rules of TT or if you plan to move up, or go racing, but there are several improvements that can be made to the IRS. Again feel free to contact me if your interested in my experience.

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MHISSTC

Your vague statement of intent to "maximize my suspension" followed by a request for what's popular and individual recommendations probably won't get you much response, not because anyone is withholding secrets, but because that's a difficult combination to provide an answer to.

 

What you'll likely end up getting is a list of 10 completely different combinations from 10 different people, some of which may only be slightly useful to you. It is going to depend upon your driving style, what kind of setup you prefer, and what the desired outcome of your modifications are.

 

What are your modification goals? In other words, you're ichin' to modify, but what do you want to accomplish with the modifications, and what specific shortcomings are there in your current setup that you want to overcome? At the extreme opposite ends of the scale, do you want to stiffen things up considerably in order to confine the factory suspension to a very small range of travel to minimize your exposure to the bad traits and maximize the predictability? Or, do you want to maintain a more compliant suspension with modifications that focus on improving the overall geometry through a larger range of motion? Do you intend to run CMC in the future, or are you planning on sticking with TT? Is your car still street driven, or is it a dedicated race car?

 

If you've already spent the chunk of change needed to install an IRS, that is an indication to me that you may desire a more compliant suspension and the modifications you are wanting to make will be more focused on improving the overall suspension geometry while keeping it more compliant. If you are heading towards the direction of making your suspension super stiff, in my mind, you are defeating the purpose of having an IRS.

 

If you are on an extreme budget that limits your track time, you might be better off simplifying your setup with single, or non-adjustable shocks and struts in order to limit the number of variables you have to contend with and instead spend the money on more track time to tweak the remaining variables. Get some NASA instructors or other racers to ride along with you to provide some driving coaching. Ride along with others if you can to sample a variety of driving styles, techniques, and car setups. Remember that no single person has all the answers that will be right for you, but you should be able to glean something useful from everyone.

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wheelhopper

I am asking because I feel like my car could be improved to handle better. My current goal is to stay in TTD for this season. The previous record in our class was in the 1.26s at Summit, in a fox body Mustang. The same car also was run in CMC. I am currently running in the 1.28s. Some guy just came in, in November, and knocked it down in the 1.24s with a Porsche boxster.

 

I have raced TT for 1 year with NASA MA and have been instructing with NASA for 3 years. This past year I instructed 4 students that were aspiring CMC drivers and already had their CMC car. The cars felt quicker around the track than mine. This plus the fact that the previous record was held by a CMC car is why I am asking the CMC guys. I figure there has to be a general recipe that gets all of the CMC cars close and then they are tweaked for each driver. I just want to see if I am close to what seems to be the most common working combos.

 

My car is pretty much track dedicated. The interior is stripped out and it has a roll cage and racing seats with harnesses. The motor is pretty much stock except for the standard bolt on items. The only reason I installed an IRS is because I needed rear discs and had a spare IRS sitting in my garage. A bonus with the IRS is that it really helped to balance the car. Here is a basic rundown of the car and how I currently have it set up, if it will aid in any suggestions. I just feel like their are some times on the track where I feel like I am getting the most out of the car and would like to see if I can find a way to cut a couple more seconds off my lap times.

 

Fox body Mustang GT

3250lbs

245 40 17 Kumho V710s on 17x8 wheels

 

Front

H&R race springs

Edelbrock struts

Steeda offset poly A arm bushings

MM camber plates

Steeda HD sway bar

Poly endlinks

x2 ball joints

MM steering rack bushings

 

-2.7 camber

1/16 toe out

3.5 caster

 

Rear

H&R race springs

factory IRS Bilsein shocks

Delrin bushings throughout

adjustable end links

 

-1.3 camber

1/16 toe in

 

 

I am not itching to mod the car, I just want to do the best I can with the mods that I have, without adding points. If that means adding stiffer springs, I'll try that, if it means softer, I'll try that, or changing sway bars, or whatever. Unfortuneately I don't have a open check to drop the car at a shop to pay $5k to set the car up. So I have to do a little research on my own and do some wrenching myself, where I can. I do get a good amount of track time, about 10 events per year, but I do plan on hiring somebody like Mike Skeen in the near future to improve my skills.

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Adam Ginsberg

FWIW, my 85 GT CMC car uses 1150lb front springs, SN95 FLCA's with Delrin bushings, MM race valved front struts, '95 GT front sway bar and StopTech front brakes.

 

Each driver has a driving style that suits them. That means what works for one driver may, or may not, work for another. Some would not like the way my suspension is set up, but it works for me.

 

Given our stock-based suspensions, at a minimum, you likely don't have enough front camber, front spring rate, or struts that can handle the increased spring rates.

 

It will be a case of trial and error to get there, especially since you have the IRS, which the CMC rules don't permit.

 

That, and using your right foot more.

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CMC#11

I would put the super race springs on all around.

Change your front camber to -3.5 on both sides.

Put the Koni DA's back on the front and put the compression and rebound on the middle settings.

 

Run the car and adjust the front struts and tire pressure according.

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cozog1548534733
FWIW, my 85 GT CMC car uses 1150lb front springs, SN95 FLCA's with Delrin bushings, MM race valved front struts, '95 GT front sway bar and StopTech front brakes.

 

Not to threadjack, but how are you legal to run SN95 FLCAs on a Fox body? I didn't see anything in the rules that allows this. Isn't that like mixing 4th gen and 3rd gen GM parts? Just curious...

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Glenn
FWIW, my 85 GT CMC car uses 1150lb front springs, SN95 FLCA's with Delrin bushings, MM race valved front struts, '95 GT front sway bar and StopTech front brakes.

 

Not to threadjack, but how are you legal to run SN95 FLCAs on a Fox body? I didn't see anything in the rules that allows this. Isn't that like mixing 4th gen and 3rd gen GM parts? Just curious...

 

It is allowed w/in model groups and allowed update/backdate rules. I color coded the groups below.

 

Model groups:

5. ELIGIBLE MANUFACTURERS/MODELS

Manufacturers:

Ford Motor Company(Early Ford)

Eligible Early Ford makes and models:

1979-95 Ford Mustang with 5.0 V8 including 1993-1995 Cobra (1993 and 1995 Cobra R models excluded)

1979-86 Mercury Capri with 5.0 V8

1996-2004 Ford Mustang with 4.6 2valve V8

1996-04 Ford Mustang with 4.6 DOHC N/A V8* (2000 Cobra R and 2003-2004 Cobra models excluded)* IRS cars must replace the IRS with standard Mustang live axle.

 

Ford Motor Company (Late Ford)

Eligible Late Ford makes and models:

2005-2011 Ford Mustang GT with 4.6 3valve V8

 

General Motors (Early GM)

Eligible Early GM makes and models:

1982-92 Chevrolet Camaro (all submodels with V8 motors eg – RS, Z28 etc)

1982-92 Pontiac Firebird (all submodels with V8 motors eg Formula, Trans-Am, WS6 etc.)

 

General Motors (Late GM)

Eligible Late GM makes and models with 5.7L V8 motors

1993-02 Chevrolet Camaro (all F-Body models with LT-1 or LS-1)

1993-02 Pontiac (all F-Body models with LT-1 or LS-1)

 

Then there is this rule:

7.3 Update/Backdate Non-body Components

Non-body components may be updated/backdated within cars of the same manufacturer on the eligible manufacturers/models list (i.e. 1982-92 GM Early components may NOT be interchanged with 1993-97 GM Late components) unless noted elsewhere in these rules.

 

So any car w/in the same model group can share parts between one another providing it is a bolt-on unless otherwise stated.

 

Clear?

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wheelhopper

Most feedback is what I suspected. My plan is to put the stiffer springs in the front. The back is staying put. There are no stiffer, conventional, springs available for the IRS. The springs I have in the rear are stiffer than what came in the '00 Cobra R anyway.

 

Not sold yet on the Konis. I know they should work better than what I have, it is just a matter of whether I can find the tuning time.

 

I have heard of the tip of using the SN95 front control arms, to gain extra -camber. Unfortuneatley I found out about this trick a month or two after I spent an entire day removing the factory control arms, removing the PITA rubber bushings, and installing the new offset poly ones. I just can't part with them yet. I'll modify my shock towers to make the -3+ camber possible.

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Tbaker95

FWIW, my 85 GT CMC car uses 1150lb front springs, SN95 FLCA's with Delrin bushings, MM race valved front struts, '95 GT front sway bar and StopTech front brakes.

 

 

I was trying to quote the above post.

 

What "perch" springs have a 1150lb spring rate?

 

What spring rate do you run in the back?

 

Do you run front and rear sway bars?

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Adam Ginsberg
What "perch" springs have a 1150lb spring rate?

 

What spring rate do you run in the back?

 

Do you run front and rear sway bars?

 

The front springs are basically stock-car style springs that fit in the standard perch on a Mustang FLCA (Hypercoil's).

 

Rear springs are H&R Race springs.

 

Front bar is from a 95 GT. Haven't run a rear sway bar since 2007.

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cozog1548534733
FWIW, my 85 GT CMC car uses 1150lb front springs, SN95 FLCA's with Delrin bushings, MM race valved front struts, '95 GT front sway bar and StopTech front brakes.

 

Not to threadjack, but how are you legal to run SN95 FLCAs on a Fox body? I didn't see anything in the rules that allows this. Isn't that like mixing 4th gen and 3rd gen GM parts? Just curious...

 

It is allowed w/in model groups and allowed update/backdate rules. I color coded the groups below.

 

Model groups:

5. ELIGIBLE MANUFACTURERS/MODELS

Manufacturers:

Ford Motor Company(Early Ford)

Eligible Early Ford makes and models:

1979-95 Ford Mustang with 5.0 V8 including 1993-1995 Cobra (1993 and 1995 Cobra R models excluded)

1979-86 Mercury Capri with 5.0 V8

1996-2004 Ford Mustang with 4.6 2valve V8

1996-04 Ford Mustang with 4.6 DOHC N/A V8* (2000 Cobra R and 2003-2004 Cobra models excluded)* IRS cars must replace the IRS with standard Mustang live axle.

 

My mistake... I was reading the 7.4 rule for body part exchanging, probably because it included 'subframe' and my brain saw 'suspension'. I missed the 7.3 rule that allows chassis exchange for the "early" and "late" groups.

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MHISSTC
...after I spent an entire day removing the factory control arms, removing the PITA rubber bushings, and installing the new offset poly ones. I just can't part with them yet. I'll modify my shock towers to make the -3+ camber possible.

 

We've been there and done that with the stock rubber bushings. After trying to knock them out, press them out, drill them out, and chisel them out, we eventually resorted to fire and burned them out. If I ever have to remove the stock rubber bushings from their shells in order to replace them with poly again, I will only use the fire method from now on. A little carbon ash cleanup with some emery cloth is all that is required after they are adequately burned away.

 

However, if you are replacing the stock rubber bushings with greaseable Delrin units, that requires the whole shell to be pressed out and replaced with the zerk'd aluminum shells included with the Delrin units. The ones I have yet to install also came with a little piece of angle iron to act as a "spacer" when pressing the bushing shells in and out so that you don't end up collapsing the control arms in the press.

 

Also, be careful how you modify your shock towers. If CMC is ever a possibility in your future, such modifications may be deemed illegal.

 

A similar and possibly cheaper alternative to the SN95 front lower control arms to gain more negative camber, that I believe you could still probably use your offset poly bushings with, are the longer fox T-bird pieces.

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Tbaker95

Thanks Adam, I didn't know Hypercoil made perch springs.

 

That gives me something to consider if my new purchase does not improve my severe understeer. I recently spoke with MM, and I purchased the H/R Super Race front springs, and the torque arm rear springs (I do not have a torque arm) and will probably have to remove the rear sway bar.

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Adam Ginsberg
Thanks Adam, I didn't know Hypercoil made perch springs.

 

The Hypercoils I linked to are very, very short. Too short for our use - you'll need some spacers to get your right height to something more normal.

 

That gives me something to consider if my new purchase does not improve my severe understeer. I recently spoke with MM, and I purchased the H/R Super Race front springs, and the torque arm rear springs (I do not have a torque arm) and will probably have to remove the rear sway bar.

 

If you don't mind, share the rest of your setup, and maybe we can help sort it out.

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Tbaker95

Hey Adam,

The set up I had that pushed/understeered like crazy was:

 

94 GT

Bilstein HD's

H/R Super Sports front and back

MM Panhard bar

MM CC Plates -3 deg, not sure about castor, in the middle

Full Cage

MM FLSFC

Diconnected stock front sway, and it helped some

Stock rear sway

255/40/17 NT05's, I plan to change to 275/40/17 R888's.

 

Keep in mind I have ordered/just received H/R Super Race front, and MM rear torque arm springs, the less stiff of the 2 they offer, or the "street" springs.

MM suggested I tighten up the front sway, and remove the rear.

 

I appreciate your suggestions.

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Adam Ginsberg
Hey Adam,

The set up I had that pushed/understeered like crazy was:

 

94 GT

Bilstein HD's

H/R Super Sports front and back

MM Panhard bar

MM CC Plates -3 deg, not sure about castor, in the middle

Full Cage

MM FLSFC

Diconnected stock front sway, and it helped some

Stock rear sway

255/40/17 NT05's, I plan to change to 275/40/17 R888's.

 

Keep in mind I have ordered/just received H/R Super Race front, and MM rear torque arm springs, the less stiff of the 2 they offer, or the "street" springs.

MM suggested I tighten up the front sway, and remove the rear.

 

Definitely reconnect the front bar. There are some Ford drivers that run without a PHB, but the majority use one to help keep the rear axle from moving around...something to keep in mind. Pull the rear bar.

 

If you can find a set of rear springs that are a lower rate than what you have, do it. I run 1150lb front springs with a set of H&R "Race" springs in the rear - not the "Super Race", just "Race". For a few years, it had Super's in the front and rear, but it pushed, so I installed the Race rears, and they've been there since.

 

Are you still using stock rubber bushings, front and rear? What RLCA's and RUCA's are you using?

 

Suspension setup is completely driver dependent - some prefer go-kart-like stiff, others want more compliance. It's all about finding what works for you.....and it will take some trial and error to figure that out.

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Tbaker95
What "perch" springs have a 1150lb spring rate?

 

What spring rate do you run in the back?

 

Do you run front and rear sway bars?

 

The front springs are basically stock-car style springs that fit in the standard perch on a Mustang FLCA (Hypercoil's).

 

Rear springs are H&R Race springs.

 

Front bar is from a 95 GT. Haven't run a rear sway bar since 2007.

 

 

Hey Adam,

Which spacer(s) do you use?

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Adam Ginsberg
Which spacer(s) do you use?

 

Spacers? Can you be more specific - wheel spacers, spring spacers?

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