Redline Motorsports
June 5th, 2006, 12:54 PM
We'll probably not too many of us playing with the LS7 but with hopes of the LS2/LS7 release looming in the near distance it won't be long. I am having a little issue with my new Z with a slight miss/surge at low rpms/loads. The car is bone stock except for a set of LT headers. I only have 1400 miles on the car and I seemed to have noticed this after the headers where installed and some miles got put on the car. At light throttle between 2000 and 3000 rpm the car has a bucking that occurs. As soon as you drop the hammer the car is gone!
I was checking out the intake tract the other day and noticed that the MAF is just a probe that is protrudes into only part of the intake snout. GM must have calibrated the MAF VERY accurately and must know how much air goes through the stock system but how much gets measured.What I mean by that is that ZI don't see how this new design can measure all the air going into the motor. I am wondering if the header install MAY have had some effect on the MAF scaling despite what we normally (with the LS1/LS6) understand. The car is also running VERY rich. All the dyno pulls we have done recorded AFR's between 11.4-11.8:1. I also in the last couple times out popped a 0430 code for something with the CATS efficiency. My scanner was also showing part throttle LTRIMS in the -12 % range.
What do you guys think?? Its not like the car is heavily modifed and has stock programming.
On another note; I found a real cool feature that GM has incorporated into the new LS7 computer. Its called ENGINE DRAG CONTROL ACTIVE. At high speeds and high rpm's when you lift from the throttle, the car displays this on the DIC and the car acts like a jake brake on a truck! It feels like the brakes are getting pulses and the throttle is played with. After some research I found that it is designed so at high speeds, lifting the throttle won't unsettle the rear of the car! Cool stuff, thought I would pass it on!
Howard
I was checking out the intake tract the other day and noticed that the MAF is just a probe that is protrudes into only part of the intake snout. GM must have calibrated the MAF VERY accurately and must know how much air goes through the stock system but how much gets measured.What I mean by that is that ZI don't see how this new design can measure all the air going into the motor. I am wondering if the header install MAY have had some effect on the MAF scaling despite what we normally (with the LS1/LS6) understand. The car is also running VERY rich. All the dyno pulls we have done recorded AFR's between 11.4-11.8:1. I also in the last couple times out popped a 0430 code for something with the CATS efficiency. My scanner was also showing part throttle LTRIMS in the -12 % range.
What do you guys think?? Its not like the car is heavily modifed and has stock programming.
On another note; I found a real cool feature that GM has incorporated into the new LS7 computer. Its called ENGINE DRAG CONTROL ACTIVE. At high speeds and high rpm's when you lift from the throttle, the car displays this on the DIC and the car acts like a jake brake on a truck! It feels like the brakes are getting pulses and the throttle is played with. After some research I found that it is designed so at high speeds, lifting the throttle won't unsettle the rear of the car! Cool stuff, thought I would pass it on!
Howard