missing power w 422
Thread Starter
Pro
Joined: Jan 2004
Posts: 525
Likes: 0
From: Morton IL
missing power w 422
LS6 Stage II w 2.057 x 1.055 62 cc
200 155.9 136
300 212.3 171.9
350 235.5 186.3
400 258.8 193.4
450 280.3 202.4
500 293.6 213.2
550 301.9 218.5
600 311.8 227.4
Cam = 248/248 .621/.621 @ 110 + 2
Exhaust = 1 7/8 Kooks w ORP & GHL's
LS6 intake
~ 11.5:1
The numbers above are from several years ago on the 346.
The first run was at ARE at time of build with limited miles on motor and TPIS 1 3/4 headers. 475 rwhp/467 rwtq
The second run is after new springs/valves/guides/retainers/etc, 1 7/8 kooks, tuning at Speed Inc and ~ 3900 miles. AFR rock solid at 12.5ish and no knock. 484 rwhp 459 rwtq
Obviously, a FAST 90 setup would help, but IMO (and others) it is still way down, especially tq wise from other 7.0L motors.
Any idea's? It almost looks like it is in a valve float condition, which still wouldn't explain the low tq...and I doubt it would get the ~ 30-40 rwhp it is down.
On a happy note, I did pick up 4 mpg on the way home from Chicago, avg 24.8 . The tune is much smoother.
http://www.ls1tech.com/forums/showthread.php?t=317867 if you want to see the dyno runs
200 155.9 136
300 212.3 171.9
350 235.5 186.3
400 258.8 193.4
450 280.3 202.4
500 293.6 213.2
550 301.9 218.5
600 311.8 227.4
Cam = 248/248 .621/.621 @ 110 + 2
Exhaust = 1 7/8 Kooks w ORP & GHL's
LS6 intake
~ 11.5:1
The numbers above are from several years ago on the 346.
The first run was at ARE at time of build with limited miles on motor and TPIS 1 3/4 headers. 475 rwhp/467 rwtq
The second run is after new springs/valves/guides/retainers/etc, 1 7/8 kooks, tuning at Speed Inc and ~ 3900 miles. AFR rock solid at 12.5ish and no knock. 484 rwhp 459 rwtq
Obviously, a FAST 90 setup would help, but IMO (and others) it is still way down, especially tq wise from other 7.0L motors.
Any idea's? It almost looks like it is in a valve float condition, which still wouldn't explain the low tq...and I doubt it would get the ~ 30-40 rwhp it is down.
On a happy note, I did pick up 4 mpg on the way home from Chicago, avg 24.8 . The tune is much smoother.
http://www.ls1tech.com/forums/showthread.php?t=317867 if you want to see the dyno runs
Safety Car
Joined: Sep 2003
Posts: 3,558
Likes: 2
From: Cape Coral FL
I'm no expert but to me the heads seem on the small side for a 422. I would imagine a 2.080 intake and at least a 1.600 exhaust valve would help. Also, the flow numbers aren't that high for a 422 IMHO, although it's hard to know what they are unless compared to a known head on the same bench. What do they flow at .650"? Your cam is pushing the valves out to .621", I wonder if they are stalling after .600"?
Looking at the AFR on the second sheet, you do drift a little rich as the rpm's go up. You might pick up ~5hp there if you go to 13:1 but you might lose some torque also.
I would say if all else is fine the heads could be larger in terms of flow numbers. What does the car run like at the track?
Looking at the AFR on the second sheet, you do drift a little rich as the rpm's go up. You might pick up ~5hp there if you go to 13:1 but you might lose some torque also.
I would say if all else is fine the heads could be larger in terms of flow numbers. What does the car run like at the track?
Last edited by ArKay99; May 6, 2005 at 11:28 PM.
