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GT500 vs Boss 302 springs...

1,231
1,013
Exp. Type
HPDE
Exp. Level
5-10 Years
Philly Metro Area
I think i would need the older style strut and strut mount to make it work.
Any spring you get will work with either type of strut mount. The mounts are strut specific and not spring specific. Part of the confusion is due to the fact that the 11-14 GT500 continued to use the older style mount (all the GT500 ones are stiffer/stronger than the 05-10 GT mounts). I went with the 11-14 Steeda Strut mount so strength is not an issue.

BTW, the published spring drop stats usually assume stock struts. I think the Koni yellows drop the height about 0.5" on their own.

I use the Roush springs (no published rates) with Koni Yellows and am very happy with them.
 

Dave_W

Cones - not just for ice cream
587
686
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
stock Boss front end geometry is already ~1/2” lower than a stock GT.
Somewhat off-topic, but were any changes made by Ford in relation to this? Or was it small enough that the engineers didn't need to "fix" the changes in roll center, bump steer, etc.? I remember reading that the Boss upper strut mounts used a stiffer rubber than GTs, though that doesn't affect geometry.
 

Grant 302

basic and well known psychic
Somewhat off-topic, but were any changes made by Ford in relation to this? Or was it small enough that the engineers didn't need to "fix" the changes in roll center, bump steer, etc.?
I have not heard of nor did I notice any hardware differences between the two cars in that regard.

My opinion is that it’s small enough of a change for a dual purpose car. Perhaps a bit much on the camber for street only and commuter cars.
 

Duane Black

Curbs go brrrppp
492
322
Exp. Type
Time Attack
Exp. Level
5-10 Years
Durham, NC
@Mad Hatter, I just read yoir old review from 2013 wheee you went a tenth quicker but apparently didnt like the feeling of the car on p springs? You admitted to being a rookie with an instructor, so I was curious if you had further review to determine if the improvement was you, the car, track conditions, etc
 

Mad Hatter

Gotta go Faster
4,647
3,359
Santiago, Chile
@Mad Hatter, I just read yoir old review from 2013 wheee you went a tenth quicker but apparently didn't like the feeling of the car on p springs? You admitted to being a rookie with an instructor, so I was curious if you had further review to determine if the improvement was you, the car, track conditions, etc

ahh I remember that now... or at least I think I do... It was because of the LCA relo brackets or lack of them to be more exact.. The track is was a very tight one with lots of slow tight corners. After increasing the LCA angle with some BMR relo brackets,the car improved dramatically with great turn in. You get a little rear wheel steer with the increased LCA angle. Without them, the car was rather crab like.

Funny, as the cars suspension improved over time, I slowly walked back the LCA angle to get more squat. But thats with coil overs and all the rest.
 

Norm Peterson

Corner Barstool Sitter
939
711
Exp. Type
HPDE
Exp. Level
5-10 Years
a few miles east of Philly
After increasing the LCA angle with some BMR relo brackets,the car improved dramatically with great turn in. You get a little rear wheel steer with the increased LCA angle. Without them, the car was rather crab like.
It's interesting to watch what happens to the roll steer % as you vary both rear ride height and spring stiffness. Let's just say I'm not surprised that running lower and stiffer rear springs can result in turn-in that's "less eager".


Norm
 

Mad Hatter

Gotta go Faster
4,647
3,359
Santiago, Chile
@Mad Hatter, I just read yoir old review from 2013 wheee you went a tenth quicker but apparently didnt like the feeling of the car on p springs? You admitted to being a rookie with an instructor, so I was curious if you had further review to determine if the improvement was you, the car, track conditions, etc

Duane, it was a while back, If memory still serves...the following year got the car down to 55.8 from 57.xx with just improvements between the wheel and the seat. Though I think I added a bigger front sway bar. Seems like ages ago. But I do remember that the relo bracket helped no end.

Later the car had Cortex coilovers and with no bar or a 18mm bar on the rear. Started at F600# / R350# springs then worked back to F500# / F300# springs
 

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