Compression/horsepower
#243250
03/04/09 07:49 PM
03/04/09 07:49 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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What would a ballpark estimate be on horsepower difference between 10.5 with iron heads and 14.0 with aluminum?
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Compression/horsepower
[Re: Von]
#243251
03/04/09 08:40 PM
03/04/09 08:40 PM
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Joined: Sep 2008
Posts: 219
so cal
cmcgee123
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its gonna depend a lot more on head flow and cam choice than compression alone.  but the results could be huge. as well as the race gas cost.
nitrous is like a really hot chick with an std you want to hit it but youre affraid of the outcome.
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Re: Compression/horsepower
[Re: Von]
#243254
03/04/09 08:56 PM
03/04/09 08:56 PM
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Joined: Mar 2006
Posts: 2,675
Mt. Eden Ky.
Hemi Allstate
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Quote:
What would a ballpark estimate be on horsepower difference between 10.5 with iron heads and 14.0 with aluminum?
FWIW I was doing a similar comparison with Comp Cams Camquest, and went from 10.5 to 14.5 and saw over 100hp increase. It does not specify iron or aluminum.
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Re: Compression/horsepower
[Re: n_bogie1984]
#243256
03/04/09 09:19 PM
03/04/09 09:19 PM
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Joined: Sep 2008
Posts: 219
so cal
cmcgee123
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why would you run such a small cam on a big inch/ decent compression motor? type in the desktop dyno on the 500" motor with a cam @ or over 600 lift and you will se a significant jump in horsepower without all the compression.
nitrous is like a really hot chick with an std you want to hit it but youre affraid of the outcome.
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Re: Compression/horsepower *DELETED*
[Re: cmcgee123]
#243257
03/04/09 11:33 PM
03/04/09 11:33 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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NE Oklahoma
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72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Compression/horsepower
[Re: forphorty]
#243258
03/04/09 11:34 PM
03/04/09 11:34 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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Quote:
howdy von. you may have already seen this,http://www.wallaceracing.com/hp-cr-chg.php
Thanks Tim, I hadnt seen that one. 
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Compression/horsepower
[Re: Von]
#243259
03/04/09 11:37 PM
03/04/09 11:37 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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Quote:
Quote:
its gonna depend a lot more on head flow and cam choice than compression alone. but the results could be huge. as well as the race gas cost.
Well, my current heads are around 260ish at .600, going to BS heads that flow [Email]326@.600.[/Email] Current cam is a 259/.585 solid, going to at least 266/.600. Race gas? Weve got E-85, dont need no stinkin race gas. 
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Compression/horsepower
[Re: Von]
#243260
03/05/09 12:24 AM
03/05/09 12:24 AM
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Joined: Aug 2003
Posts: 43,119
Bend,OR USA
Cab_Burge
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I Win
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Posts: 43,119
Bend,OR USA
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I have yet to see a desk top program match real world results  Maybe I shouldn't buy or use cheap desk top programs Maybe no two computers and dynos are identicle   I had two 440 motors with identicle bore and stroke motors,4.38 bore and 3.75 stroke. Motor #1 was 14.7 to one compression with a set of B1-BS heads with 440 port sizes and a Crane custom ground solid roller that was 274@.050 ground on 106 LSA in at 105, BME aluminum rods, it made 627 HP. Motor #2 was 12.8 to 1 comp. ratio with a set of ported 906 heads with 2.14 intake valves and 1.81 exhaust valves, these heads flowed 14 CFM less than the B1-BS heads did on the same Super Flow 600 bench, the cam was a Cam Dynamics R282 solid roller ground on 108 LSA installed at 106 ILC, that motor made 625 HP on the same DTS dyno six months later Both motors had the same type intake, M1 4500 and the same Dominator carburetor, Holley 1050 CFM List # 9375 , motor #1 and #2 both used C12 race fuel, two different batches 6 months apart
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Compression/horsepower
[Re: cmcgee123]
#243261
03/05/09 01:44 AM
03/05/09 01:44 AM
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Joined: Dec 2003
Posts: 5,314
Carstairs, Alberta, Canada
dave571
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Quote:
its gonna depend a lot more on head flow and cam choice than compression alone.
The heads and the cam are the heart of the motor.
I've seen tests in mags where they took a motor, dyno'd it, then started adding gaskets to reduce compression. The loss of compression had a surprisingly small effect on the peak hp.
Most builders say 1 point of comp alone will only ad 3% to a given combo.
The combo needs to be matched. Obviously you wouldn't run the same cam in a 10:1 iron motor, as a 14:1 alum motor. Add in that it is pretty unlikely that you'd ever get a iron head to flow like an aluminum one. Not because of the material, just because the alum head will be designed as a performance head.
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Re: Compression/horsepower
[Re: dave571]
#243262
03/05/09 02:12 AM
03/05/09 02:12 AM
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Posts: 1,260
Las Vegas NV
moparmanjames
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Las Vegas NV
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Quote:
Quote:
its gonna depend a lot more on head flow and cam choice than compression alone.
The heads and the cam are the heart of the motor.
I've seen tests in mags where they took a motor, dyno'd it, then started adding gaskets to reduce compression. The loss of compression had a surprisingly small effect on the peak hp.
Most builders say 1 point of comp alone will only ad 3% to a given combo.
The combo needs to be matched. Obviously you wouldn't run the same cam in a 10:1 iron motor, as a 14:1 alum motor. Add in that it is pretty unlikely that you'd ever get a iron head to flow like an aluminum one. Not because of the material, just because the alum head will be designed as a performance head.
I agree on the article as well, I'm not sure if it was the same article but with a 440 and a bunch of steel shim gaskets I think they went from 13:1 down to around 9:1 and they lost roughly 20hp per point.
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Re: Compression/horsepower
[Re: quickd100]
#243265
03/05/09 11:59 PM
03/05/09 11:59 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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Quote:
One other thing to look at, the piston dome required to get that high compression. In some cases you can loose more than you gain due to the negative effect the dome has on the flame front. Dave
No domes needed with the small chambers of the bs heads, at least not for 14 to 1.
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Pretty much figure about 45hp per compression point on a big block V8.
