lid, K&N and tune results on a 1998 A4
09-30-2007, 01:52 AM
#1
lid, K&N and tune results on a 1998 A4 Test car is a 1998 z28 A4 that has a bone stock motor. Not a single mod done to the engine or ECU. It has a 12 bolt with 3.73 gears. Chevron 91 octane gas. All runs done with converter unlocked. Dyno is a Mustang dyno at Dougs Dynopower in Henderson, tuning by me. For a reference point, most head/cam cars i've tuned on this dyno have made in the 360-370 rwhp range. All numbers are SAE corected.
First run no mods. Car made 260 RWHP peak, 285 RWTQ. Car was detonating itself to death and had an AF ratio of 12.7:1.
Installed LS1 motorsports air lid with same paper filter
269 RWHP / 290 RWTQ peak. Detonating itself to death and A/F went to 13.8:1
Same setup with with 3 degrees of timing pulled and the a/f at 13.2:1
269 RWHP peak 290 RWTQ Peak, car was once again detonating but only over 5000 rpms now.
Installed K&N Airfilter. Car made 272 RWHP peak and 290 RWTQ peak. It picked up 7 RWTQ everywhere below 5k rpms though. A/f was 13.2:1 again and was detonating up top.
The final tune ended up with a 12.6:1 a/f, 21 degrees of timing at the torque peak rising to 24 degrees at 5600 rpms. That is 4-5 degrees lower than stock. Final numbers were 275 RWHP / 297 RWTQ peak. What the peak numbers don't show is what it gained under the curve. Here is the graph.
As you can tell, tuning the car for HP is not effective at this level but is still needed to prevent the engine from detonating like crazy. The stock tune is just too agressive for 91 octane in many cases. Adding a lid only exacerbates the issue. Since this car is an A4 it's possible to greatly improve the driving experience through tuning the transmission and making the car more fun to drive. Detonation was not audible in the car and could only be detected by scanning. Outside the car it was extremely audible and sounded like a bunch of marbles in the engine. Might want to consider running 100 octane for beating on the car if it's untuned. With headers and a better muffler this car should pick up quite a bit of power under the curve as well as some peak power. With the stock exhaust a cutout is almost always worth another 10 rwhp and is much cheaper than a cat back exhaust.
Hope everyone enjoys the read.
First run no mods. Car made 260 RWHP peak, 285 RWTQ. Car was detonating itself to death and had an AF ratio of 12.7:1.
Installed LS1 motorsports air lid with same paper filter
269 RWHP / 290 RWTQ peak. Detonating itself to death and A/F went to 13.8:1
Same setup with with 3 degrees of timing pulled and the a/f at 13.2:1
269 RWHP peak 290 RWTQ Peak, car was once again detonating but only over 5000 rpms now.
Installed K&N Airfilter. Car made 272 RWHP peak and 290 RWTQ peak. It picked up 7 RWTQ everywhere below 5k rpms though. A/f was 13.2:1 again and was detonating up top.
The final tune ended up with a 12.6:1 a/f, 21 degrees of timing at the torque peak rising to 24 degrees at 5600 rpms. That is 4-5 degrees lower than stock. Final numbers were 275 RWHP / 297 RWTQ peak. What the peak numbers don't show is what it gained under the curve. Here is the graph.
As you can tell, tuning the car for HP is not effective at this level but is still needed to prevent the engine from detonating like crazy. The stock tune is just too agressive for 91 octane in many cases. Adding a lid only exacerbates the issue. Since this car is an A4 it's possible to greatly improve the driving experience through tuning the transmission and making the car more fun to drive. Detonation was not audible in the car and could only be detected by scanning. Outside the car it was extremely audible and sounded like a bunch of marbles in the engine. Might want to consider running 100 octane for beating on the car if it's untuned. With headers and a better muffler this car should pick up quite a bit of power under the curve as well as some peak power. With the stock exhaust a cutout is almost always worth another 10 rwhp and is much cheaper than a cat back exhaust.
Hope everyone enjoys the read.
