Re: Gains switching to larger intake valve
[Re: 416challenger]
#468393
09/14/09 10:26 PM
09/14/09 10:26 PM
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Joined: Jul 2006
Posts: 4,595 On the south side of Nowhere
S/ST 3040
master
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master
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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Quote:
I will be freshening up my motor after this season and I was considering going from a 2.02 valve to a 2.05. What kind of gains if any can be had? The heads are Edelbrock RPM that flow the as followed-
Intake Exhaust .100" 82.8 N/A .200" 149.0 112.1 .300" 211.2 169.3 .400" 255.6 203.2 .450" 269.4 218.0 .500" 276.3 226.0 .550" 281.5 229.8 .600" 284.6 231.2 .650" 284.6 231.5 .700" 284.6 232.9
The cam is 262in 268ex @.050 w/ 675" lift. I would like to run 7.00 in the heat, I normally run around 7.09 @ 3800 da. Has anyone made a similar change, if so what kind of results?
82.8 CFM @ .100" lift??
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Re: Gains switching to larger intake valve
[Re: goldmember]
#468394
09/14/09 10:28 PM
09/14/09 10:28 PM
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Joined: Jan 2003
Posts: 8,035 Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,035
Tulsa OK
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On my ported X heads I changed from stock 2.02 valves to a race style 2.05 intake and it picked up .2, I don't recall how much MPH it gained. I also replaced the stock exhaust valves with SS valves as well so there might be some gain from that.
68 Barracuda Formula S 340
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Re: Gains switching to larger intake valve
[Re: Bad340fish]
#468395
09/14/09 11:01 PM
09/14/09 11:01 PM
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Joined: Feb 2004
Posts: 4,501 Gainesville,FL
goldmember
master
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master
Joined: Feb 2004
Posts: 4,501
Gainesville,FL
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You bring up a good point. I have seen gains of .2 in the 1/8mile with a simple valve angle change,same valves. It's obvious that it was on different days so weather and track conditions cannot be ruled out.
Last edited by goldmember; 09/14/09 11:02 PM.
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Re: Gains switching to larger intake valve
[Re: 416challenger]
#468397
09/14/09 11:42 PM
09/14/09 11:42 PM
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Joined: Jul 2006
Posts: 4,595 On the south side of Nowhere
S/ST 3040
master
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master
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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Quote:
S/ST 3040-What did you mean by your comment???
82.8 CFM @ .100" is not even in the ball park.
I've been through this before and I've never seen a 2.02" valve flow more than 66 CFM @ .100" Being that far off at .100" lift, only makes me question the 284+ at higher lifts.
I've seen similar flow numbers before, posted here.
Contrary to popular belief, this is a subject I know a little about.
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Re: Gains switching to larger intake valve
[Re: 416challenger]
#468399
09/15/09 12:01 AM
09/15/09 12:01 AM
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Joined: Jul 2006
Posts: 4,595 On the south side of Nowhere
S/ST 3040
master
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master
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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Unless you send them back to the same guy to flow them with the 2.05 valves, you are going to be very disappointed. I can tell from your flow sheet. 2.02" valve is capable of flowing at least 324 CFM @ .700" 2.05" valve is OK in an Edelbrock head but, you won't see any improvement unless the valve job on 2.02" seat was no good to begin with. This is a set I did with the valves listed: ...........INTAKE........................ EXHAUST .100"_____64.1___________________54.6 .200"____131.6__________________118.6 .300"____194.4__________________158.6 .400"____242.5__________________177.1 .500"____270.8__________________192.4 .550"____279.3__________________199.5 .600"____282.2__________________204.4 2.055" IN x 1.600" EX
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Re: Gains switching to larger intake valve
[Re: S/ST 3040]
#468402
09/15/09 07:42 AM
09/15/09 07:42 AM
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Joined: Dec 2004
Posts: 415 New Braunfels, TX
416challenger
OP
mopar
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OP
mopar
Joined: Dec 2004
Posts: 415
New Braunfels, TX
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My combination is-73 Challenger, 418 cid, 11.55:1 comp, Edelebrock RPM heads, Vitor intake, 950HP carb, 262in 268ex 675" lift, 727 tran, 9 1/2" 4800 converter, Dana 60 w/ 4.10 gears, 28 x 12.5 ET Street tire, and the weight is 3720 w/ driver. I have ran a best of 6.92 @97.2 and 10.98 @120.7 w/ 1.50 60' time.
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Re: Gains switching to larger intake valve
[Re: cgall]
#468405
09/15/09 10:00 AM
09/15/09 10:00 AM
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Joined: Mar 2005
Posts: 2,172 Ohio
theclutcher
top fuel
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top fuel
Joined: Mar 2005
Posts: 2,172
Ohio
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Quote:
Probably no gain unless you unshroud the valve by machining the combustion chamber.
if that is shrouded, you can expect very little then bore size comes into play. imo...
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Re: Gains switching to larger intake valve
[Re: theclutcher]
#468406
09/15/09 10:18 AM
09/15/09 10:18 AM
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Joined: Jul 2006
Posts: 4,595 On the south side of Nowhere
S/ST 3040
master
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master
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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Quote:
Quote:
Probably no gain unless you unshroud the valve by machining the combustion chamber.
if that is shrouded, you can expect very little then bore size comes into play. imo...
Anytime I've tried unshrouding the intake valve (straight wall side) on an OEM head, it hurt flow. I haven't tried it on the RPM though.
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Re: Gains switching to larger intake valve
[Re: 416challenger]
#468407
09/15/09 10:20 AM
09/15/09 10:20 AM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Quote:
Intake Exhaust .100" 82.8 N/A .200" 149.0 112.1 .300" 211.2 169.3 .400" 255.6 203.2 .450" 269.4 218.0 .500" 276.3 226.0 .550" 281.5 229.8 .600" 284.6 231.2 .650" 284.6 231.5 .700" 284.6 232.9
The cam is 262in 268ex @.050 w/ 675" lift.
If the port already stalls at .550 then adding more valve without adding port volume ahead of it isn't going to do much. I don't think shrouding is an issue. Or it's less of one than many think. I am curious tho... with those flow numbers, why such a small duration and huge lift? I would think more power will be made staying in the .650 range but adding another 15°-20° of duration at .050. I wouldnt have specd a cam any taller than .630 for those heads.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Gains switching to larger intake valve
[Re: S/ST 3040]
#468410
09/16/09 09:10 AM
09/16/09 09:10 AM
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Joined: Mar 2005
Posts: 2,172 Ohio
theclutcher
top fuel
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top fuel
Joined: Mar 2005
Posts: 2,172
Ohio
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Quote:
Quote:
Quote:
Probably no gain unless you unshroud the valve by machining the combustion chamber.
if that is shrouded, you can expect very little then bore size comes into play. imo...
Anytime I've tried unshrouding the intake valve (straight wall side) on an OEM head, it hurt flow. I haven't tried it on the RPM though.
That is interesting, Have only seen the opposite.
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