4th gear slipping

Sam Ehret · 01-09-2017, 04:29 PM

I keep burning the clutch in 4th gear only. Got 15 runs since fresh. getting old. 69 Camaro, 3360 lbs, 7.25 dual disk clutch, 1188 base, 406 chevy sb,
126-128 mph, 10.7's, 1.48-1.5 60ft, 2.52,1.91,1.46,1 trans, 5.38 gears, 9" slicks,.........thinking of changing base to 1380. Any comments would be appreciated. (CW is........)

Sean Marconette · 01-09-2017, 04:50 PM

What is the CW? CW is typically used for high gear lockup. If you use just base to set your launch and high gear, it will be a compromise of dragging the motor down or knocking the tires loose on launch. Base is used to set launch, and CW for high gear.

With 10.7 your 60' is very soft, it may have a lot to do with your 2.52 first gear too.

Sean

Mike Pearson · 01-09-2017, 04:57 PM

Are you shifting using the clutch or clutchless. Using the clutch needs more pressure than clutchless. 406 has a lot of torque. With the 252 low you might be burning the clutch in low gear as well. I would think a 1st gear in the 290 range would be better for that combo.

Sam Ehret · 01-09-2017, 05:14 PM

Yes, I'm using a clutch to shift. 29.5" tires
My launch rpm is 4800 on the two step. When I shift from 3-4 my rpm drops to around 5500. That's the point where I smoke(drive thru) the clutch.

01-09-2017, 04:29 PM	#1
Sam Ehret Junior Member Join Date: Jul 2014 Posts: 18 Likes: 4 Liked 0 Times in 0 Posts	4th gear slipping I keep burning the clutch in 4th gear only. Got 15 runs since fresh. getting old. 69 Camaro, 3360 lbs, 7.25 dual disk clutch, 1188 base, 406 chevy sb, 126-128 mph, 10.7's, 1.48-1.5 60ft, 2.52,1.91,1.46,1 trans, 5.38 gears, 9" slicks,.........thinking of changing base to 1380. Any comments would be appreciated. (CW is........)

01-09-2017, 04:50 PM	#2
Sean Marconette Senior Member Join Date: Mar 2006 Posts: 958 Likes: 618 Liked 165 Times in 60 Posts	Re: 4th gear slipping What is the CW? CW is typically used for high gear lockup. If you use just base to set your launch and high gear, it will be a compromise of dragging the motor down or knocking the tires loose on launch. Base is used to set launch, and CW for high gear. With 10.7 your 60' is very soft, it may have a lot to do with your 2.52 first gear too. Sean __________________ Sean Marconette 84 Mustang 5060 SS/N

01-09-2017, 04:57 PM	#3
Mike Pearson VIP Member Join Date: Mar 2007 Posts: 2,320 Likes: 546 Liked 1,629 Times in 502 Posts	Re: 4th gear slipping Are you shifting using the clutch or clutchless. Using the clutch needs more pressure than clutchless. 406 has a lot of torque. With the 252 low you might be burning the clutch in low gear as well. I would think a 1st gear in the 290 range would be better for that combo. __________________ Mike Pearson 2485 SS

01-09-2017, 05:14 PM	#4
Sam Ehret Junior Member Join Date: Jul 2014 Posts: 18 Likes: 4 Liked 0 Times in 0 Posts	Re: 4th gear slipping Yes, I'm using a clutch to shift. 29.5" tires My launch rpm is 4800 on the two step. When I shift from 3-4 my rpm drops to around 5500. That's the point where I smoke(drive thru) the clutch.