26" vs 28" drag radials
Thread Starter
Instructor
Joined: Sep 2009
Posts: 169
Likes: 1
From: Sacramento CA
26" vs 28" drag radials
I am currently running 28" M&H Racemasters and am having a hard time getting anything better than a 1.8x 60'. My best run so far is an 11.1@129 with a 1.89 60'. I am thinking about switching to a 26.5" setup on 17" wheels. Has anyone made the switch from 28 to 26 or vice versa?
My car is in a M6 in the 500rwhp range with a Z06 transmission and 3.42 gears. I would think my launches would improve, trap speed would increase and my clutch would not have to work so hard out of the hole.
Any advice would be much appreciated.
My car is in a M6 in the 500rwhp range with a Z06 transmission and 3.42 gears. I would think my launches would improve, trap speed would increase and my clutch would not have to work so hard out of the hole.
Any advice would be much appreciated.
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
The record holding cars run 28" but they have 4.10 gears. The best run I have seen was a 9.75 with 4.10's.
By using a 28" with 3.42's you have killed the final gear ratio. Also, if you arent near redline in 4th crossing the traps, you are essentially lowering your average HP during the run.
By using a 28" with 3.42's you have killed the final gear ratio. Also, if you arent near redline in 4th crossing the traps, you are essentially lowering your average HP during the run.
Burning Brakes
Joined: May 2006
Posts: 1,110
Likes: 16
From: stuart fl
I have both setups but my car is an auto 6 speed with a stall and gears
1st I ran the 26' mt with 17' rims and pulled low 1.6s to mid 1.5s and ran around 11.1/2s
2nd I swapped to the 28' mt with 17' rims and about a half inch wider, I pulled the same kind short times and mph but for some reason the best run I could ever get out of them was an 11.50. yes I did tune for them and keep trying them for about 5 track visits.
After having a hard time getting the times back down with the 28's I just simply swapped back to my 26's and retuned shift points and went straight back to an 11.16. I know this might not help you since you have a manual.
Good luck
1st I ran the 26' mt with 17' rims and pulled low 1.6s to mid 1.5s and ran around 11.1/2s
2nd I swapped to the 28' mt with 17' rims and about a half inch wider, I pulled the same kind short times and mph but for some reason the best run I could ever get out of them was an 11.50. yes I did tune for them and keep trying them for about 5 track visits.
After having a hard time getting the times back down with the 28's I just simply swapped back to my 26's and retuned shift points and went straight back to an 11.16. I know this might not help you since you have a manual.
Good luck
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
I understand your problem, as it's the same issue that Z06 cars have. You can easily finish the 1/4 in 3rd with the current tires, but you'll have to shift to 4th just before the traps (loosing time) if you run the smaller 275/40 x 17 tires.
One solution is to run the 17" wheels with 315/35 x 17 Hoosier tires.
The Hoosiers are lighter and sticker. The 315s will give you more width for the launch and hopefully enough height to avoid the 3-4 shift before the stripe. I'm assuming with your mods you're not RPM limited to under 7000.
Us A6 guys run the 275s, but we don't have the clutch problem either.
One solution is to run the 17" wheels with 315/35 x 17 Hoosier tires.
The Hoosiers are lighter and sticker. The 315s will give you more width for the launch and hopefully enough height to avoid the 3-4 shift before the stripe. I'm assuming with your mods you're not RPM limited to under 7000.
Us A6 guys run the 275s, but we don't have the clutch problem either.
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
but you'll have to shift to 4th just before the traps (loosing time) if you run the smaller 275/40 x 17 tires.
One solution is to run the 17" wheels with 315/35 x 17 Hoosier tires.
The Hoosiers are lighter and sticker. The 315s will give you more width for the launch and hopefully enough height to avoid the 3-4 shift before the stripe.
One solution is to run the 17" wheels with 315/35 x 17 Hoosier tires.
The Hoosiers are lighter and sticker. The 315s will give you more width for the launch and hopefully enough height to avoid the 3-4 shift before the stripe.
Thread Starter
Instructor
Joined: Sep 2009
Posts: 169
Likes: 1
From: Sacramento CA
Thanks for the feedback. I currently enter the traps just before redline in 3rd gear. Not shifting into fourth is nice, but I would trade a shift for a better 60' and less stress on the clutch. I am thinking about going to a set of 275/40/17 Hoosiers.
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Sounds like there's some of that funky new math there someplace.
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Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I've had both the 275 and 315's. They are essentially the same height. The shorter tire will help the launch a lot. The fast bolt on z06 guys use the 17" tires.
The shift to fourth won't hurt much at all. The first 330 feet matter much more than the last.
The shift to fourth won't hurt much at all. The first 330 feet matter much more than the last.
