i am running 23x8.5x15s right now, in a k20a eg. and im having a problem with having to shift into 5th gear at the very end of the 1320. i did some math, and figured if i went with 24.5 inch slicks, each time my tire rotated, i would be 4.5 inches further ahead then i would with the 23s. there is 15,840 inches in a 1/4mile. so if i put on the 24.5s, i should be able to get past the line, without shifting into 5th. but.....i dont know if it just works like that. i mean, would it actually make a difference? or would it take more power to turn those slicks they way i turn the 23s now. im kind of stuck, any help is appreciated. thanks alot.

 

go to http://www.autocrossing.com
click on gearing calculator, click witch tranny you have and the diameter of your slicks, and your redline, and it will show you when you'll shift in each gear

 

Well I'm running 24.5's on my K20A but I have the JDM type R set-up it was fine running to about 114mph then I need 5th.. I think the decision might be better based on hp than gearing though... As your 60ft's might suffer a little from running the biger tyre.. But I dont know really, I run 1.8 60's on our local track with VHT.. I will find out how much of a difference VHT makes on sunday if the weather is fine..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hondog &raquo;</TD></TR><TR><TD CLASS="quote">Well I'm running 24.5's on my K20A but I have the JDM type R set-up it was fine running to about 114mph then I need 5th.. I think the decision might be better based on hp than gearing though... As your 60ft's might suffer a little from running the biger tyre.. But I dont know really, I run 1.8 60's on our local track with VHT.. I will find out how much of a difference VHT makes on sunday if the weather is fine..</TD></TR></TABLE>

im running the type r tranny too. ive already ordered the 24.5s so im gonna give them a try. what is your redline in that thing?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by aLLmTRaLLdAY &raquo;</TD></TR><TR><TD CLASS="quote">

what is your redline in that thing?</TD></TR></TABLE>

Might be better off just raising the red lind just a little

 

I agree...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b18cx &raquo;</TD></TR><TR><TD CLASS="quote">Might be better off just raising the red lind just a little</TD></TR></TABLE>

the motor is bone stock. stock redline is 8400, ive got it at 8600, i dont know if i want to go much higher than that. id need to be at a little over 9000rpms to end in 4th with the 23 inch slicks.

 

I run my K20A-R to 8800 mine starts to fall of power around 8600 though not by much though... So I was running 113-114mph at 8800 in 4th on the JDM 6spd.. I beleive now with some more weight reduction and abit more power I can get closer to trapping at 120mph...

 

niel wat time we heading out on saterday