|
|
![]() |
#1 |
Junior Member
Join Date: Oct 2012
Location: Sydney , Australia
Posts: 97
Likes: 23
Liked 43 Times in 25 Posts
|
![]() |
![]() |
![]() |
![]() |
#2 |
Senior Member
Join Date: Nov 2007
Location: Div. 6, Eastern, WA
Posts: 709
Likes: 2,666
Liked 238 Times in 111 Posts
|
![]()
Assuming good traction, a change to a 30 inch tall tire would require roughly a 4.4 gear to turn the engine the same RPM, so if you can take a little more RPM a 4.56 gear should work nicely. & be quicker. (depending on your powerband)
__________________
Dave Noll, EF/S ,?/SA 6526 |
![]() |
![]() |
![]() |
#3 |
Junior Member
Join Date: Oct 2012
Location: Sydney , Australia
Posts: 97
Likes: 23
Liked 43 Times in 25 Posts
|
![]()
thanks Dave,
funny as it seems I only shift at 6000,trap around 63/6400. not sure of pulling harder with the rods(ly with ARP bolts),peak power on chassis dyno is around 5500 but pulls happily to 6500 never went past here I did used to run 3.9 gears with the 28" as to quicker with more gear - car is able to run faster than the class Tex |
![]() |
![]() |
![]() |
#4 |
Senior Member
Join Date: Nov 2007
Location: Div. 6, Eastern, WA
Posts: 709
Likes: 2,666
Liked 238 Times in 111 Posts
|
![]()
Well if your peak is 5500 & you figure 5% past peak for a trap then your current gear should be correct. But just putting a taller tire on what you have your 60' will be slower but the motor will be happier in the light's. test, test, test.
![]()
__________________
Dave Noll, EF/S ,?/SA 6526 |
![]() |
![]() |
![]() |
#5 |
Junior Member
Join Date: Oct 2012
Location: Sydney , Australia
Posts: 97
Likes: 23
Liked 43 Times in 25 Posts
|
![]()
Thanks Dave,
Wiil check with hoosier for age of 30x9 slicks i have Then off to test Tex |
![]() |
![]() |
![]() |
#6 |
Junior Member
Join Date: Oct 2012
Location: Sydney , Australia
Posts: 97
Likes: 23
Liked 43 Times in 25 Posts
|
![]()
Dave ,
just an update . Tested on Saturday . You were right re gearing it did feel a little soft through the top end . But the 60 wasn't that much different to talk about .1.542/1.541/1.532/1.543 I was wrong in that I didn't pick up any MPH . I back to backed the 30x9 against the 275 both Hoosier radials , the 30x9 is several years ,maybe 5 or 6 , old and the 275 about 55 passes and gone after the last pass . the 30x9 went 6.920/919 @98.71/98.59MPH( 1/8")10.936/942@121.07/120.93MPH . 733/794 DA the 275 went 6.880/886@99.14/99.30MPH(1/8") 10.881/884@121.85/121.90 MPH. 387/405DA Car obviously likes a little more gear thanks again, Tex |
![]() |
![]() |
![]() |
|
|