sumpin' i learned yesterday (rt question)

Ed Wright · 06-09-2014, 09:11 PM

I have to use 28" tires, I can't imagine getting a green light with 24". What kind of car is this that you can use 24" tires?

Tom keedle · 06-10-2014, 05:20 AM

Quote:

Originally Posted by Ed Wright

I have to use 28" tires, I can't imagine getting a green light with 24". What kind of car is this that you can use 24" tires?

67 American...
I don't think I can get 28" in the frt, probably 26's

I've got the freeplay completely out, helped the shifting a lot ,was having issues (stone stock used st-10 3.42 1st gear)

measured 'em again today 24.5"....
would have to trim the fenders for much taller...or raise the ride height

Ed Wright · 06-10-2014, 01:47 PM

Stock tires on my Firebird were 25.7", so I started with 26". I didn't notice it going any faster after the 28"s, just more green lights. After hearing how taller fronts show faster on time slips I decided to A-B-A test that. (I wear my junk out testing) I borrowed a set of 26" fronts. Back-to-back-to-back testing showed about nothing. I understand the therory, but calling it one hundredth of a second difference on my car (which repeats very well) would be a stretch.

Jim Caughlin · 06-10-2014, 02:07 PM

I agree with Mark's comment, clutch travel adjustment is the stick version of a delay box. A couple of turns seems to be about .01 on my car. Your leg obviously doesn't move nearly as fast as a finger so it makes for big changes. Definitely have to make adjustments from altitude to sea level tracks.

Also played around with tire pressure but it didn't seem to make any noticable difference in RT. I was curious so did some measuring in the shop, changed from 40 PSI all the way down to 25 and didn't measure any noticable squish in the tire that made for more rollout. Makes me wonder if this is just one of those ideas that is more mental than real when it comes to RT's.

Jim Caughlin
SS 6019

Ed Wright · 06-10-2014, 02:12 PM

Jim, I have played with front tire pressure and couldn't tell much either. Blamed that on myself not repeating well. Rear tire pressure has more effect as far as I can tell.

Ed Carpenter · 06-10-2014, 04:33 PM

The more air gap you have the slower your reaction times will be. When I tried a blinder it stopped the red lights.

The Hawk · 06-10-2014, 07:27 PM

Quote:

Originally Posted by deuces wild

The more air gap you have the slower your reaction times will be. When I tried a blinder it stopped the red lights.

Does a blinder work well at night? Bandimere`s events often finish in the dark.

magnumv8 · 06-12-2014, 06:17 PM

If there are any rubber bump stops in the front suspension you can trim them down a little at a time until you get the lights you are looking for....this increases the front end travel which leaves the tires in the beams longer.....

D L Rambo.....Stk 1300

G Anderson · 06-15-2014, 04:43 PM

Dark Glasses(even at night,then I thro them up on the dash)

06-09-2014, 09:11 PM	#1
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: sumpin' i learned yesterday (rt question) I have to use 28" tires, I can't imagine getting a green light with 24". What kind of car is this that you can use 24" tires? __________________ Ed Wright 4156 SS/JA

06-10-2014, 01:47 PM	#3
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: sumpin' i learned yesterday (rt question) Stock tires on my Firebird were 25.7", so I started with 26". I didn't notice it going any faster after the 28"s, just more green lights. After hearing how taller fronts show faster on time slips I decided to A-B-A test that. (I wear my junk out testing) I borrowed a set of 26" fronts. Back-to-back-to-back testing showed about nothing. I understand the therory, but calling it one hundredth of a second difference on my car (which repeats very well) would be a stretch. __________________ Ed Wright 4156 SS/JA

06-10-2014, 02:07 PM	#4
Jim Caughlin Senior Member Join Date: Mar 2002 Location: Woodburn, Or Posts: 685 Likes: 82 Liked 805 Times in 245 Posts	Re: sumpin' i learned yesterday (rt question) I agree with Mark's comment, clutch travel adjustment is the stick version of a delay box. A couple of turns seems to be about .01 on my car. Your leg obviously doesn't move nearly as fast as a finger so it makes for big changes. Definitely have to make adjustments from altitude to sea level tracks. Also played around with tire pressure but it didn't seem to make any noticable difference in RT. I was curious so did some measuring in the shop, changed from 40 PSI all the way down to 25 and didn't measure any noticable squish in the tire that made for more rollout. Makes me wonder if this is just one of those ideas that is more mental than real when it comes to RT's. Jim Caughlin SS 6019

06-10-2014, 02:12 PM	#5
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: sumpin' i learned yesterday (rt question) Jim, I have played with front tire pressure and couldn't tell much either. Blamed that on myself not repeating well. Rear tire pressure has more effect as far as I can tell. __________________ Ed Wright 4156 SS/JA

06-10-2014, 04:33 PM	#6
Ed Carpenter Live Reporter Join Date: May 2006 Location: Dripping Springs, Tx Posts: 2,709 Likes: 186 Liked 520 Times in 132 Posts	Re: sumpin' i learned yesterday (rt question) The more air gap you have the slower your reaction times will be. When I tried a blinder it stopped the red lights. __________________ Ed Carpenter 2005 Chevy Cobalt A/SM Race Engine Development

06-12-2014, 06:17 PM	#8
magnumv8 Member Join Date: Feb 2009 Location: Coraopolis, Pa. Posts: 172 Likes: 0 Liked 0 Times in 0 Posts	Re: sumpin' i learned yesterday (rt question) If there are any rubber bump stops in the front suspension you can trim them down a little at a time until you get the lights you are looking for....this increases the front end travel which leaves the tires in the beams longer..... D L Rambo.....Stk 1300

06-15-2014, 04:43 PM	#9
G Anderson Member Join Date: Dec 2009 Location: Iowa Posts: 105 Likes: 13 Liked 4 Times in 3 Posts	Re: sumpin' i learned yesterday (rt question) Dark Glasses(even at night,then I thro them up on the dash)