ET streets+3.90 gears??
Thread Starter
Instructor
Joined: Dec 2000
Posts: 193
Likes: 0
From: Phoenix, Arizona AZ
ET streets+3.90 gears??
I just installed 3.90 gears and the CCW drag setup with Mickey Thompson ET streets. What tire pressure and launch rpm should I be running? My best previous ET was 12.70 @ 111.14mph. What improvements can I expect? Thanks.
Le Mans Master
Joined: Jan 2001
Posts: 5,786
Likes: 6
From: Lafayette Colorado
Re: ET streets+3.90 gears?? (enloe)
Did you get the harden cross output shaft installed also? If not, with the gears and tires, you will snap the stock one fairly soon. I have 3.90:1 gears, ET Streets, 3800 stall converter, and the harden output shaft; I am launching at about 3600 rpms and am getting 1.65 60' times off motor.
Keith
Keith
Melting Slicks
Joined: Apr 2001
Posts: 3,034
Likes: 125
From: NY-South Florida
Re: ET streets+3.90 gears?? (kromberg)
First question is is do you have line lock on the car? You really need to get some heat into those tires. I'm sure the ZO6 clutch will not last too long either.
I have seen the best results with 10-12 psi in the tires. You will have to leave higher then you think with the stick because the ET's are going to want to pull the motor down hard on launch. For example I leave at 5200 and it pulls the motor down to around 4600, where peak torque is.
Trail and error are the only real options. Everything else is just opinions!
I have seen the best results with 10-12 psi in the tires. You will have to leave higher then you think with the stick because the ET's are going to want to pull the motor down hard on launch. For example I leave at 5200 and it pulls the motor down to around 4600, where peak torque is.
Trail and error are the only real options. Everything else is just opinions!
Le Mans Master
Joined: Jul 1999
Posts: 5,005
Likes: 38
From: jackson nj
Re: ET streets+3.90 gears?? (9D9LS1)
As mentioned, the only method that works is trial and error. I run 15 lbs (cold) in my 11.5 ET Streets and with my A4 and 4000 Precision converter it launches with 1.51-1.53 60' times.
