increasing high flow lift numbers ONLY?
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From: Kansas City, KS
increasing high flow lift numbers ONLY? here's the situation, I think this will be a great 'experiment'
I 'maxed' out my heads when I put in a bigger cam. it made absolutely no more power anywhere, but lost TQ below 4500. this is with 5.7L heads and 2.02 intake valves. Soooo, I had my head porter put in 2.08 valves. my cam is a FMS 253/261 .642 110+4. I'm running stock rockers and Melling lifters. oh, and this is a 408.
here's the results in CFM
.500 +4
.550 +6
.600 +12
.650 +17
flow numbers below .500 were completley unchanged. The exhaust was also left the same.
any guesses on results?? I'm installing the heads tomorrow and will have it dyno'd saturday. I'm guessing +10rwhp in my powerband.
I 'maxed' out my heads when I put in a bigger cam. it made absolutely no more power anywhere, but lost TQ below 4500. this is with 5.7L heads and 2.02 intake valves. Soooo, I had my head porter put in 2.08 valves. my cam is a FMS 253/261 .642 110+4. I'm running stock rockers and Melling lifters. oh, and this is a 408.
here's the results in CFM
.500 +4
.550 +6
.600 +12
.650 +17
flow numbers below .500 were completley unchanged. The exhaust was also left the same.
any guesses on results?? I'm installing the heads tomorrow and will have it dyno'd saturday. I'm guessing +10rwhp in my powerband.
Last edited by 383ss; Oct 25, 2005 at 05:27 PM.
8-14 rwhp gain is the range I came up with, but 10 rwhp gain is pretty much a safe bet.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Thread Starter
10 Second Club
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From: Kansas City, KS
well, preliminary results are seriously diapponting.
down 15rwhp and 25rwtq on the EXACT same hp/tq curve.
it put down 530/490. on that dyno before it put down 545/515
other things I changed: added FTRA, and 28W tires from regular 28X10.5's.
a/f was about 12.5:1
the only encouraging thing is that a buddy of mine was down 30rwhp/tq from a few months earlier and hes barely even driven his car. I'm going to do some tuning on the street and put the regular 28's on and go back to see what it does.
down 15rwhp and 25rwtq on the EXACT same hp/tq curve.
it put down 530/490. on that dyno before it put down 545/515other things I changed: added FTRA, and 28W tires from regular 28X10.5's.
a/f was about 12.5:1
the only encouraging thing is that a buddy of mine was down 30rwhp/tq from a few months earlier and hes barely even driven his car. I'm going to do some tuning on the street and put the regular 28's on and go back to see what it does.
Last edited by 383ss; Nov 6, 2005 at 07:54 AM.
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Thread Starter
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From: Kansas City, KS
well, I don't have enough open spring pressure now 
its only 375 and I need about 450. I'll swap them out and redyno. was getting some bad valve float.
its only 375 and I need about 450. I'll swap them out and redyno. was getting some bad valve float. Last edited by 383ss; Nov 6, 2005 at 10:58 PM.
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Thread Starter
10 Second Club
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Joined: Mar 2002
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From: Kansas City, KS
ok, I jumped the gun. its not floating them, I have no idea what the hell is wrong. its down 20-30rwhp/tq everywhere. did a compression check real quick and it was ok. going to pull the intake and check for cracks or somthing. I'm lost on this one...
If the only thing changed in your setup was the heads, maybe the max port job cost you airspeed/velocity or perhaps your mid-lift flow is not as good as it once was. Sorry to hear your results were not positive. It sucks to throw money away.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
Thread Starter
10 Second Club
iTrader: (14)
Joined: Mar 2002
Posts: 2,893
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From: Kansas City, KS
mid and low lift numbers are the same. wait a week and then look at my results. something is not right. I've not given up yet. I think my valve seals need some work...