missing power w 422
05-06-2005, 05:30 PM
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missing power w 422 LS6 Stage II w 2.055 x 1.057 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
~ 11.9:1
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.
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
~ 11.9:1
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. Last edited by Greg Fell; 09-30-2005 at 02:44 PM.
05-07-2005, 12:09 AM
#4
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Look at the exhaust flow. 227 
at .600
That is very weak for a stroker that size. I think that could account for some loss.
IMO, send those heads to TEA for some upgrades.
at .600That is very weak for a stroker that size. I think that could account for some loss.
IMO, send those heads to TEA for some upgrades.
05-07-2005, 07:41 AM
#5
The valve sizes seem a bit small, but the flow numbers do not necessarily help. If those flow numbers are no inatke and no pipe on the exhaust, they are about average. You can have two "Stage 2" heads flow the same CFM with a rounded or clayed opening, lets say 300cfm at .550" lift. Then once the intake is bolted down, one can drop to 280cfm and the other to 265 cfm and swirl can be affected differently also.
The horsepower is off, but not too bad, but the torque is way down for sure. generally a 422-427 will make about equal torque and horsepower unles overcammed or over headered. In this case the 248 cam, may be too much for the heads and/or the 1 7/8 headers may be hurting the torque if the heads can not flow enough. Just a couple ideas for you.
Mike Norris
The horsepower is off, but not too bad, but the torque is way down for sure. generally a 422-427 will make about equal torque and horsepower unles overcammed or over headered. In this case the 248 cam, may be too much for the heads and/or the 1 7/8 headers may be hurting the torque if the heads can not flow enough. Just a couple ideas for you.
Mike Norris
05-07-2005, 06:11 PM
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Hi Dave, I got the motor right at the tail end of when all the sheot hit the fan...basically last october/november. Nick said he personally went through the shortblock and it is ok, has a Cola 4" Crank, Ohio Rods with ARP 2000 bolts, Diamond -7cc pistons. I did have a problem a month or so ago with the heads, I lost cyl 1, it had a bent valve (they said 5 total?). I think the heads were not looked at, just plopped down on my new shortblock. The valve tips were worn funny, etc. They replaced last month with same castings, new valve job, and all new hardware. Pat Golds, valves, etc.
I was supposed to have gotten new 6.0 heads with a more modern port job and a state III setup, which was definately an influencing factor with choosing them. However, in the mayhem I ended up getting my old castings, which would have been fine if they were/are able to adequately feed the 422.
I went to track today, and ran a best of
11.204 @ 124.93 (1.769)
11.106 @ 125.38 (1.640)
11.061 @ 125.69 (1.688)
11.026 @ 126.09 (1.660)
DA was 1290ish.
I had one run where I launched great, 1.520, but blew the hose off the master and could not shift, dang it. Not bad for an Al flywheel, 1st time at track, and a 6 speed with 3.42 Would have been an 10.80.
I was supposed to have gotten new 6.0 heads with a more modern port job and a state III setup, which was definately an influencing factor with choosing them. However, in the mayhem I ended up getting my old castings, which would have been fine if they were/are able to adequately feed the 422.
I went to track today, and ran a best of
11.204 @ 124.93 (1.769)
11.106 @ 125.38 (1.640)
11.061 @ 125.69 (1.688)
11.026 @ 126.09 (1.660)
DA was 1290ish.
I had one run where I launched great, 1.520, but blew the hose off the master and could not shift, dang it. Not bad for an Al flywheel, 1st time at track, and a 6 speed with 3.42
Would have been an 10.80. Trending Topics
05-07-2005, 06:15 PM
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Originally Posted by Mike Norris
The valve sizes seem a bit small, but the flow numbers do not necessarily help. If those flow numbers are no inatke and no pipe on the exhaust, they are about average. You can have two "Stage 2" heads flow the same CFM with a rounded or clayed opening, lets say 300cfm at .550" lift. Then once the intake is bolted down, one can drop to 280cfm and the other to 265 cfm and swirl can be affected differently also.
The horsepower is off, but not too bad, but the torque is way down for sure. generally a 422-427 will make about equal torque and horsepower unles overcammed or over headered. In this case the 248 cam, may be too much for the heads and/or the 1 7/8 headers may be hurting the torque if the heads can not flow enough. Just a couple ideas for you.
Mike Norris
The horsepower is off, but not too bad, but the torque is way down for sure. generally a 422-427 will make about equal torque and horsepower unles overcammed or over headered. In this case the 248 cam, may be too much for the heads and/or the 1 7/8 headers may be hurting the torque if the heads can not flow enough. Just a couple ideas for you.
Mike Norris
09-30-2005, 12:41 PM
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Is the top of the graph, where it noses over, indicative of valve float?
I'm wondering if my YT 1.8's are causing this, as the heads only had ~ 400 miles on them at the time of the 2nd dyno (speed inc).
I'm wondering if my YT 1.8's are causing this, as the heads only had ~ 400 miles on them at the time of the 2nd dyno (speed inc).
09-30-2005, 01:55 PM
#10
Part of the problem is the cam. 248/248 on a 110+2 is peaking way to early because of the ICL being 108. It should help get you more torque, but it's obvious that is not the case either. The other is your compression ratio is much too low for a cam of that size (assuming it's around an XE or maybe XE-R type lobe). Your static compression is 11.5, so I assume you went with a 12cc or thereabouts dished piston, and with a 248/248 on XE lobes, it comes out to around 8:1 DCR. That could be higher, which would definitely help out torque.
And, as far as the torque being down, a number of strokers only make around 470-480rwtq. Your heads are not helping there, and neither are those headers. The Kooks are 1-7/8", and that's not the problem, the problem is they need to have 30" primaries or longer, not 24". That hurts torque in the midrange and down low.
Also, ditch the Yella Terras. They are too heavy and if you don't have a He-man spring or solid roller, it will hurt performance more than help on a hydraulic setup. (Also, since they are not adjustable, they don't make a good solid roller rocker either.)
My suggestion is to run a cam that will make good use of your current compression ratio to bring the dynamic compression up, and that will extend your RPM range. And, since you'll need to replace those YT rockers, you might as well go with a street solid roller setup and run either the Crane Quick Lift Gold stud mounted rockers, or some Comp shaft mount. Comp has an Xtreme Street Roller lobe that would be good. Grind a new cam using those lobes for a 248/254 .654"/.660" on a 112+0 LSA. Should peak around 6200-6300rpm, will give you more torque, and the split favoring the exhaust will overcome the weakness of your heads.
With the FAST LSX90 port matched to your heads and that cam, 520-530rwhp should be achievable.
And, as far as the torque being down, a number of strokers only make around 470-480rwtq. Your heads are not helping there, and neither are those headers. The Kooks are 1-7/8", and that's not the problem, the problem is they need to have 30" primaries or longer, not 24". That hurts torque in the midrange and down low.
Also, ditch the Yella Terras. They are too heavy and if you don't have a He-man spring or solid roller, it will hurt performance more than help on a hydraulic setup. (Also, since they are not adjustable, they don't make a good solid roller rocker either.)
My suggestion is to run a cam that will make good use of your current compression ratio to bring the dynamic compression up, and that will extend your RPM range. And, since you'll need to replace those YT rockers, you might as well go with a street solid roller setup and run either the Crane Quick Lift Gold stud mounted rockers, or some Comp shaft mount. Comp has an Xtreme Street Roller lobe that would be good. Grind a new cam using those lobes for a 248/254 .654"/.660" on a 112+0 LSA. Should peak around 6200-6300rpm, will give you more torque, and the split favoring the exhaust will overcome the weakness of your heads.
With the FAST LSX90 port matched to your heads and that cam, 520-530rwhp should be achievable.
09-30-2005, 01:59 PM
#12
In that case, the 248/256 can be run on a 114+0 LSA to lower the DCR down a bit.
Or, you can now go with a Comp XE-R hydraulic setup (which will be cheaper). 244/248 .612"/.615" 114+0 LSA. I'd recommend that over the solid roller, but just run stock or Crane stud mounted 1.7 rockers.
I wouldn't worry with the LS7 yet. You've already got lots of money tied up in the current engine. A better cam will help you out. I like the solid roller or XE-R type lobes, because they do produce more torque, because the ramp rates are so fast.
Or, you can now go with a Comp XE-R hydraulic setup (which will be cheaper). 244/248 .612"/.615" 114+0 LSA. I'd recommend that over the solid roller, but just run stock or Crane stud mounted 1.7 rockers.
I wouldn't worry with the LS7 yet. You've already got lots of money tied up in the current engine. A better cam will help you out. I like the solid roller or XE-R type lobes, because they do produce more torque, because the ramp rates are so fast.
09-30-2005, 02:06 PM
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Originally Posted by JakeFusion
In that case, the 248/256 can be run on a 114+0 LSA to lower the DCR down a bit.
Or, you can now go with a Comp XE-R hydraulic setup (which will be cheaper). 244/248 .612"/.615" 114+0 LSA. I'd recommend that over the solid roller, but just run stock or Crane stud mounted 1.7 rockers.
I wouldn't worry with the LS7 yet. You've already got lots of money tied up in the current engine. A better cam will help you out. I like the solid roller or XE-R type lobes, because they do produce more torque, because the ramp rates are so fast.
Or, you can now go with a Comp XE-R hydraulic setup (which will be cheaper). 244/248 .612"/.615" 114+0 LSA. I'd recommend that over the solid roller, but just run stock or Crane stud mounted 1.7 rockers.
I wouldn't worry with the LS7 yet. You've already got lots of money tied up in the current engine. A better cam will help you out. I like the solid roller or XE-R type lobes, because they do produce more torque, because the ramp rates are so fast.
Theoretically, the LS7 stuff wont be that much. $250ish for the manifold, the heads are $550 bare, so 1k each? The rockers are $350ish. I can sell my heads/fast intake/1.8 YT's and do it for not too much dough, and an assload of power increase, hopefully. I'll recam then.
09-30-2005, 02:43 PM
#14
Sorry, the 248/254 on a 114 LSA will lower the DCR compared to the 248/254 on a 112. With a 114 LSA, it'll be in the 8.7:1 range with 12.1:1 SCR, which is a tad high for 93 octane, but since you are running it at 12.5:1 A/F, it should be fine. If it were a little leaner, I might worry. I know the G5X3-114 and 59cc AFR 205 on a 346 runs about a 8.6:1 DCR on 93 without any problems.
I recommended the 112 when I thought you had 11.5:1 CR, but on 12.1:1, the 114 will do better and extend your RPM range a bit. I read 11.5:1 in the first post and missed the one where you said you had 7cc dished pistons.
If you do the LS7 top end, then yeah, I would wait on the cam. But, if you are going to switch over everything, you might as well look into the solid roller stuff. With the LS7s high flow heads, I'd go even bigger, because it will make power.
The Comp Xtreme Street Roller lobes I'd look at:
.006/.050/.200 lift
286/248/170 .654"
292/254/176 .660"
298/260/181 .666"
304/266/187 .677"
The 248/254 will drive better than your current 248, and the 260/266 will probably make a huge amount of power with the LS7 top end and still drive well. The 254/260 would be somewhere in between.
I recommended the 112 when I thought you had 11.5:1 CR, but on 12.1:1, the 114 will do better and extend your RPM range a bit. I read 11.5:1 in the first post and missed the one where you said you had 7cc dished pistons.
If you do the LS7 top end, then yeah, I would wait on the cam. But, if you are going to switch over everything, you might as well look into the solid roller stuff. With the LS7s high flow heads, I'd go even bigger, because it will make power.
The Comp Xtreme Street Roller lobes I'd look at:
.006/.050/.200 lift
286/248/170 .654"
292/254/176 .660"
298/260/181 .666"
304/266/187 .677"
The 248/254 will drive better than your current 248, and the 260/266 will probably make a huge amount of power with the LS7 top end and still drive well. The 254/260 would be somewhere in between.
09-30-2005, 02:52 PM
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I'm interested in solid roller, however, I've always thought it was a ton of money more.
How much more would a solid roller setup be? And what kind of rockers can I run (that aren't 1k+...Jesels)
How much more would a solid roller setup be? And what kind of rockers can I run (that aren't 1k+...Jesels)
09-30-2005, 03:09 PM
#16
T&D or Comp make some that run around $800-$900, and Crane has some that are coming out price TBD. Or, you could run the Crane stud mounted 1.7s. The kit is $700 or so. But you'd need custom length pushrods if you mill the LS7s and run the solid lifters (Morel being awesome). So, maybe a supporting vendor can piece you a kit together with the proper lifters, springs, pushords and rockers to go with the Cam. I don't know if the LS7s heads will need clearancing for a shaft rocker, however.
The alternative is the Comp LSK hydraulic lobe. Just run stout springs and good lifters, and you'll be good. You'll just need more compression to help with DCR and torque at the bottom end and midrange. The solid rollers have very aggressive ramp rates, so they don't need as much compression to create cylinder pressure (DCR). The lazier the lobe and the longer the duration, the more compression it "bleeds off."
.006/.050/.200 lift
297 247 171 .656"
301 251 175 .660"
305 255 179 .663"
309 259 183 .663"
313 263 186 .663"
12.75:1 CR and the 255/263 on a 112 would work well and give you an 8.4:1 DCR.
The alternative is the Comp LSK hydraulic lobe. Just run stout springs and good lifters, and you'll be good. You'll just need more compression to help with DCR and torque at the bottom end and midrange. The solid rollers have very aggressive ramp rates, so they don't need as much compression to create cylinder pressure (DCR). The lazier the lobe and the longer the duration, the more compression it "bleeds off."
.006/.050/.200 lift
297 247 171 .656"
301 251 175 .660"
305 255 179 .663"
309 259 183 .663"
313 263 186 .663"
12.75:1 CR and the 255/263 on a 112 would work well and give you an 8.4:1 DCR.
