A bit disappointed in new baseline
Thread Starter
Joined: Jan 2002
Posts: 4,069
Likes: 74
From: Casselberry FL
A bit disappointed in new baseline First, I don't have a method of scanning my dyno sheet.
My old engine was a stock short block, Stage I heads, 218/226 112+4 cam, current LS6 intake, current Grot headers, 3.42's. Compression worked out to around 10.7:1. Tuned on 4/26/03, 13:1 AFR across the board, peak numbers were 398rwhp/380rwtq. The wideband was installed pre-cat passenger side.
Current engine is a used forged 346 with ~11.2:1 compression, same heads, 228/228 114 ARE cam (came installed in block), same intake, same exhaust, 3.73's & T2R differential. Baselined 405/362 on 7/12/04. AFR was basically 11.8 <-> 12.2 from 2500 -> 5600, dropped to ~11.5:1 at 5900, then linearly back up to 12:1 at 6500. The wideband was installed post-cat passenger side.
This time I want it to be ~13:1 on the street, not on the dyno. So I guess that means I want it 12.7:1'ish on the dyno. I wasn't expecting to take such a big torque hit. Since this is a street car I want that torque. Both were on the same dyno, except the dyno moved to a new building last month. Both runs are SAE.
What should I expect from leaning out the AFR?
My old engine was a stock short block, Stage I heads, 218/226 112+4 cam, current LS6 intake, current Grot headers, 3.42's. Compression worked out to around 10.7:1. Tuned on 4/26/03, 13:1 AFR across the board, peak numbers were 398rwhp/380rwtq. The wideband was installed pre-cat passenger side.
Current engine is a used forged 346 with ~11.2:1 compression, same heads, 228/228 114 ARE cam (came installed in block), same intake, same exhaust, 3.73's & T2R differential. Baselined 405/362 on 7/12/04. AFR was basically 11.8 <-> 12.2 from 2500 -> 5600, dropped to ~11.5:1 at 5900, then linearly back up to 12:1 at 6500. The wideband was installed post-cat passenger side.
This time I want it to be ~13:1 on the street, not on the dyno. So I guess that means I want it 12.7:1'ish on the dyno. I wasn't expecting to take such a big torque hit. Since this is a street car I want that torque. Both were on the same dyno, except the dyno moved to a new building last month. Both runs are SAE.
What should I expect from leaning out the AFR?
Originally Posted by JimMueller
The wideband was installed post-cat passenger side.
Thread Starter
Joined: Jan 2002
Posts: 4,069
Likes: 74
From: Casselberry FL
They're the same cats I had on the old engine. If they're good, they're staying on. If they're bad, they get replaced. I'm not running without cats.
Brad: That was my impression as well. They were originally going to use the tailpipe sniffer, but I requested using a bung since that was the way the place had always done it in the past. It wasn't until after the pulls I realized they used the post-cat bung instead of pre-cat. I was told it wouldn't have any effect on a properly operating cat. Which way are the readings skewed if used post-cat?
Brad: That was my impression as well. They were originally going to use the tailpipe sniffer, but I requested using a bung since that was the way the place had always done it in the past. It wasn't until after the pulls I realized they used the post-cat bung instead of pre-cat. I was told it wouldn't have any effect on a properly operating cat. Which way are the readings skewed if used post-cat?
