Roush Trak Pak

[DusterRT]

Well, right there is my answer. 340/175, that's way, WAY out of whack. I found a 20% difference front to rear was too much for balance. Your front springs are stiffer than H&R Race which are way stiffer than any other street spring. Your rears are the softest of any rates, basically just what Steeda Sports are.

They don't revalve Koni's, so if the valving is not OTS (off the shelf), I'd be shocked (no pun intended). Further, of the "authorized service centers for Koni, I've not found one that hasn't screwed up--including different valving in a pair of front struts for a SN95 Bullitt. I have Koni do all my revalving when required.

So what would your recommendation for me be as far as getting this more optimized? Softer in front? Stiffer in the back? I've been very happy with the performance so far and the car's composure has had nothing but praise from instructors, but I will say I feel like I understeer more than I'd like (of course, who doesn't say this!). Being my first year out in the car, I adjusted nothing but tire pressures in order to get a "baseline" feel for the car since my suspension tuning experience is virtually nil at this point. Probably noteworthy is that I don't autocross anymore (local venues are drying up unfortunately!), so my on-track time is all on road courses.

Other considerations though are the LCA relocation brackets which are putting my LCA's at a notable downward angle, despite the rear being fairly low. The more I'm reading about that, I am thinking I might be wise to remove them and add a bit of rear ride height to get the LCA's close to level (and the subsequent rise in roll center would be...good? Bad? Negligible?). Correct me if I'm wrong, but this should reduce roll oversteer, correct? But would that increase understeer?

Maybe I should start my own thread..

 

[Sam Strano]

You can do a lot of things... The LCA angle should not be tail down that's not helping. I think the front is stiffer than it needs to me, the rear is softer than it needs to be. You could leave it alone and go with a lot more rear bar to balance it. Again, this is a reason I opted for adjustable bars, because it's easier, cheaper and less hassle than buying a lot of different springs, and running a little more bar instead of more spring works better over bumps.

I'd start with the adjustable rear bar to gain some wheel rate and balance the car better. Any spring changes can be better assessed then to dial the car in. With 340 front (which is an odd number, don't know how that is because coil-over springs come in 25 pound increments from Eibach which is what they use)... So right there I have cause to doubt (you can see the rate on the springs, it's part of the number).

To make a decent balance with those fronts (assuming that is what they are) we're talking around 300's. Basically that's pretty close, a little stiffer, than H&R Race spring sets for an S197. I run those WITH my bars and I run the rear bar in the middle setting too.

I'm sure I can help you make the car better. Just a matter of how you want to play the springs front and rear vs. each other... regardless you'll still want at least the rear bar (IMHO, which is why I did them). I'm a believer in moderate springs and moderate bars. Frankly I'd not run the H&R Race springs forever. I like the balance, but it's way too firm, and doesn't need to be that stiff. Just part of the testing and tuning process.

 

[DusterRT]

Thanks for the input Sam. So as far as your rear bar; is there a setting that is about the same as the stock bar or are all three positions stiffer?

With 340 front (which is an odd number, don't know how that is because coil-over springs come in 25 pound increments from Eibach which is what they use)... So right there I have cause to doubt (you can see the rate on the springs, it's part of the number).

I thought so too. The front and rear springs use a different numbering system though, the rears being a traditional Eibach part number (#1000.250.0175), but the fronts seem to be metric and possibly made for Ground Control (#GC200.64.58). Only the front springs have GC branding on them.

Googling the number brings me to a page on GC's website stating it's a 340 lb/in sping, and another site explains that the part number is metric and the 58 at the end means 58 newton-meters. Interestingly that site gives a conversion factor of x5.7 which gives a figure of just over 330 lb/in, and if you use a normal unit conversion calculator, it says 58 n/m is 513 lb/in..?

Here's the GC page (look above the picture for the p/n and spring rate):
http://www.ground-control-store.com/products/description.php/II=778/CA=8

Another data point, Kaldar has the street/track kit on his car and I think he said his rates are 380/200 or maybe it was 380/225..again, odd front rate and normal in the back. I'm curious what Griggs uses on their front street system, as they appear to be GC struts painted yellow (even their product description is a direct copy/paste from the GC website). I PM'd marksti who just happens to be selling his after going SLA but he has yet to get back to me.

 

[Random Asshole]

"Big bars"? No, not really, there are bigger bars for both ends... My front bar starts about 5% stiff and works up, the rear starts about 20% stiffer and works up. Far from huge and in fact smaller than Hotchkis, Hellwig, H&R, Steeda Comp rear. Same OD as Steeda front (and regular rear), Eibach.... but with less weight from being hollow and of course also adjustable at both ends too.

Communication error. "Big on bars" = you believe that the stock sway bars are too soft..Not "you like physically bigger bars." And not to say you don't have good reason. I haven't had the variety of parts that you've thrown at your car, so I'm certainly not saying that you're wrong. You're experienced enough to know what you want and how you're gonna do it.

But for the regular "Joe Shmo" that just wants better handling who has no idea how to set up a car: I'd focus all my attention on shocks, sticky rubber, and camber first. Then drive the hell out of it until you can't possibly get any faster. The stock bars will do you well and will help you learn what it is you want out of the car down the road.

You'd all agree that camber will take the cake in the price vs. effect comparo against stiffer bars, right?

 

[dkegel]

But for the regular "Joe Shmo" that just wants better handling who has no idea how to set up a car: I'd focus all my attention on shocks, sticky rubber, and camber first. Then drive the hell out of it until you can't possibly get any faster. The stock bars will do you well and will help you learn what it is you want out of the car down the road.

You'd all agree that camber will take the cake in the price vs. effect comparo against stiffer bars, right?

Personally, one of the first things I'd do (and did) is throw a larger rear sway bar on the car. These cars understeer quite a bit in stock form. A larger rear bar makes a big difference. Camber doesn't solve that.

Dave

 

[Random Asshole]

Personally, one of the first things I'd do (and did) is throw a larger rear sway bar on the car. These cars understeer quite a bit in stock form. A larger rear bar makes a big difference. Camber doesn't solve that.

Dave

Say Wha?? If that's the case, then I'm not going to post as single thing for the rest of my life because I apparently don't have any idea wtf I'm talking about and should take my car to autozone for my mods and advice..

Have you tried more than -2 or more degrees in the front?

 

[Kaldar142]

I'd have to say +1 on the rear bar.... it definitely helps balance out the car ALOT better.

I've also experimented with a TON of different camber settings (from -.8 to -3.5) and i've found -2.5 is best for my needs.

With that being said, going from stock alignment (-.8) to -1.6 was a HUGE difference, turn in was night and day. The car just cut thru the corners with ease, you can really 'feel' it. VERY confidence inspiring.

I'm a huge fan of camber and use it to my best advantage

 

[Gray Ghost GT]

Personally, one of the first things I'd do (and did) is throw a larger rear sway bar on the car. These cars understeer quite a bit in stock form. A larger rear bar makes a big difference. Camber doesn't solve that.

Dave

???. Running more negative camber (-2.0 or better) up front will definitely help reduce understeer compared to stock alignment settings. My dedicated track car is running -2.8 based on years of testing/adjustments.

 

[dkegel]

Say Wha?? If that's the case, then I'm not going to post as single thing for the rest of my life because I apparently don't have any idea wtf I'm talking about and should take my car to autozone for my mods and advice..

Have you tried more than -2 or more degrees in the front?

Well, OK, sorry. I do realize you know what you're talking about. And no, I have not tried that much camber on the Mustang. I"m only at about -1.5. It's still mainly a street driven car and I would be worried about tire wear with a ton of camber. I do understand that neg. camber is your (my) friend. I used to run -2.5 front/-2 rear on my SHO with Toyo RA1s.

I do still recommend a larger rear bar though.

Dave

 

[Random Asshole]

Well, OK, sorry. I do realize you know what you're talking about. And no, I have not tried that much camber on the Mustang. I"m only at about -1.5. It's still mainly a street driven car and I would be worried about tire wear with a ton of camber. I do understand that neg. camber is your (my) friend. I used to run -2.5 front/-2 rear on my SHO with Toyo RA1s.

I do still recommend a larger rear bar though.

Dave

It was a sarcastic joke. Difficult to do through text. lol. Not saying the bar won't help, but that was the last place in my mind to start looking for adjustments. Anyway, I'd seriously look into getting some plates or doing the plate/camber bolt combo like dave suggested in a post. NTB will also give you free alignments for life after you paid for the first one. I've gotten quite a few "checkups" from there. -2.5 degrees does absolute wonders coupled with some sticky rubber.

 

[DusterRT]

My dedicated track car is running -2.8 based on years of testing/adjustments.

So is this on the Mustang or are you wandering into Sqidd territory?

(I've been running -2.5 and zero toe...if you're wearing out the insides of your tires, you're not getting enough track time! )

 

[Sam Strano]

Thanks for the input Sam. So as far as your rear bar; is there a setting that is about the same as the stock bar or are all three positions stiffer?


The front and rear springs use a different numbering system though, the rears being a traditional Eibach part number (#1000.250.0175), but the fronts seem to be metric and possibly made for Ground Control (#GC200.64.58). Only the front springs have GC branding on them.

Googling the number brings me to a page on GC's website stating it's a 340 lb/in sping, and another site explains that the part number is metric and the 58 at the end means 58 newton-meters. Interestingly that site gives a conversion factor of x5.7 which gives a figure of just over 330 lb/in, and if you use a normal unit conversion calculator, it says 58 n/m is 513 lb/in..?

Here's the GC page (look above the picture for the p/n and spring rate):
http://www.ground-control-store.com/products/description.php/II=778/CA=8

Another data point, Kaldar has the street/track kit on his car and I think he said his rates are 380/200 or maybe it was 380/225..again, odd front rate and normal in the back. I'm curious what Griggs uses on their front street system, as they appear to be GC struts painted yellow (even their product description is a direct copy/paste from the GC website). I PM'd marksti who just happens to be selling his after going SLA but he has yet to get back to me.

Sorry for the delay, having issues with getting posts to stick for some reason.....

My rear bar is stiffer in all settings than stock. My bar is a hollow 22mm, stock is a solid 20. My bar is slightly softer at full soft than solid 22's like Steeda and Eibach. But, obivously, can be made stiffer too.

I have no flipping idea why they are going that. The front springs are just 2.5", common. And come in 25 lbs increments. They are using standard springs in normal old pounds in the rear, but then use a Euro spring in the front? Ok........ My guess is the size of the spring isn't made in pound rates by Eibach. I use Hypercoil when I run/need coil-over springs, so I do not have an Eibach ERS catalog around to check that out.

Camber wise, I run more than -2, less than -2.5. Great tire wear, and balance-- don't have any reason to run more and sacrifice the braking power.

 

[Gray Ghost GT]

So is on the Mustang or are you wandering into Sqidd territory?

(I've been running -2.5 and zero toe...if you're wearing out the insides of your tires, you're not getting enough track time! )

Good one. LOL. My Mustang GT is currently at -1.8 since its seeing more daily driver time than road course, but my Corvette C5 is at -2.8 that I've been running on the road course since 2005 (dedicated track car), not sure if its an apples to oranges comparison, but its no motorcycle, LOL!

I found the best way to check for the optimal camber settings, regardless of car manufacturer, is to check your tire temperatures after coming off the track with a Tire Pyrometer - measuring the inside, middle and outside of the tire tread vs. monitoring where its wearing the most over time. The goal is similar temps.

 

[Thinkkker]

To add to the hijack here,
Wow, you guys are soft!
My setup is always near close to backwards from Sam *Hi Sam! *, but I think I have done decent in the car.

I have the AST shocks on the car and prepped mine for STU/ESP in autox. i started with 500/250 on the spring rates, then jumped to 750/250, and have setteled on 900/350. The car is very neutral and I still have the stock rear bar with a Steeda adjustable front set on full stiff. Now, the car is VERY LOW. Its liveable on the street, but way to sprung for a roadcourse and to low to run on the street with speed bumps and steep entry ways. I know normally carpool with the wife and have a second street car so the Mustang can rest at home.

I know on a standard GT or Bullitt, if you want to have a FS car *corner carver with stock springs*, I would go Bilstein. My co-driver from two years ago hated Koni, and I was a little unimpressed with the Tokico's from where I sat and he decided to get the bilstein. I told him the suspension settings to run and the car ran flawlessly! I was impressed.

I do agree with Sam though, that you need to have a diffinative plan first. Then go build. I also agree that the strut suspension is not that bad. I plan to forgo any SLA on a mustang that I build.

Kent

 

[Sam Strano]

Like anything, folks will always have their own reasoning for doing what they do.

Am I "soft". Well, the car doesn't roll. Kent's car is way, way, way stiffer than anything I'd do. I just don't see the point of making a car that has a suspension into a defacto go-kart. I believe, and it's served me well, that you make a car only as stiff as you need it to be to control your camber curve and contact patch because that's where mechanical grip lives. If run a car with downforce you'd need more spring to counter that force. Most of us don't have aero. Look at Nextel Cup cars, when they need mechanical grip vs. aero grip (road courses, short tracks like Martinsville), they move around a lot because they aren't sprung very stiff at all to get that power down and not cause the tires to slide on turn in. If it rains or it's bumpy these things matter even more because you need the suspension to work and not jar the car around on bumps, and you want to load the tires less abruptly in the rain.

I'm sadly going to have to hold off on my little ESP Mustang project (because I want a 2011 and don't want to build a car for 1 year only). I want to do that because I want to show again what a "soft" car can do.

Bilstein's offer no tuning ability what-so-ever. Anyone trying to setup a car to work should have adjustable dampers. I know that didn't help you at all Kent on day 2 in 2008 @ Nationals. When the course got more sweeping you could have used some help in getting that car to rotate... I don't think that would have been a bad thing.

Please note I sell Bilstein... and AST (having some built now in fact), and Koni, and Tokico too.

 

[usmcpony]

Stupid question, what suspension does the P-51A and B have?

 

[SoundGuyDave]

Twin oleos on the main gear, and solid mount on the tail....


Sorry.

 

[DusterRT]

Twin oleos on the main gear, and solid mount on the tail....


Sorry.

ROFL!

 

[ArizonaGT]

Stupid question, what suspension does the P-51A and B have?

Roush Stage 3, I believe. The main differentiator of that car is that it has the TVS blower as opposed to the M90.

 

[fiverivers]

Roush Stage 3, I believe. The main differentiator of that car is that it has the TVS blower as opposed to the M90.

the only difference between the P51-A and B is the single blower belt (for A) and duel blower belt(For B)