HP difference between 11.1 and 13.4 compression
#1592008
03/12/14 03:37 PM
03/12/14 03:37 PM
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Joined: Feb 2005
Posts: 20,174
PA.
pittsburghracer
OP
"Little"John
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OP
"Little"John
Joined: Feb 2005
Posts: 20,174
PA.
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Just throwing this out there to see if anyone has done any testing (especially track testing) going from a 11.1 compression pump gas combo to a 13.4 race gas or alcohol engine.
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: HP difference between 11.1 and 13.4 compression
[Re: pittsburghracer]
#1592009
03/12/14 03:44 PM
03/12/14 03:44 PM
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Joined: Jan 2012
Posts: 2,646
Stuttgart, Arkansas
rickseeman
master
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master
Joined: Jan 2012
Posts: 2,646
Stuttgart, Arkansas
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On a bracket race 572 Hemi I think of the difference between pump gas (10 to 1) and high compression as being nearly 100 horsepower. Your results may vary.
2011 Drag Pak Challenger
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Re: HP difference between 11.1 and 13.4 compression
[Re: pittsburghracer]
#1592010
03/12/14 04:40 PM
03/12/14 04:40 PM
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Joined: Aug 2003
Posts: 43,180
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,180
Bend,OR USA
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The 1963 N.W. low compression, 11 1/4 to 1 was 415 advertised HP and the high compression, , 13.5 to 1 was 425 HP  I changed the heads and compression on my 505 C.I. wedge motor this winter, no track results yet  T hat motor made 685 HP on race gas and 676 HP on E85 tuned for best power,it made more torque with the E85 though than on race gas  It was 11.4 to 1 comp. ratio then, it is 12.8 to 1 now with the new Eddy Victor M.W.. Supposedily they flow about 30 CFM(60 HP maybe gain  ) more than the CNC ported Eddy RPM 440 port size heads I took off 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: HP difference between 11.1 and 13.4 compression
[Re: Cab_Burge]
#1592011
03/12/14 05:36 PM
03/12/14 05:36 PM
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Joined: Feb 2004
Posts: 2,073
Tulsa, Ok
WadeMetzinger
top fuel
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top fuel
Joined: Feb 2004
Posts: 2,073
Tulsa, Ok
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On my wife's car which is 10.5:1 small block, we just moved from 750 pump gas to 950HP Alcohol and it picked the car up just a little over 3 tenths 11.20s to 10.90s but that is still with 10.5:1 compression.
Alcohol make more improvements in low compression motors than ones that are 13:1, for one because your already running high octane fuel like 110.
Wade Metzinger 918-809-0987 71 Cuda 9.28@145 -1s, Pglide 68 Cuda 10.64@124 1.45 60's 318->390 eddys Moparts discount code on WIX - moparts www.Filter1.com
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Re: HP difference between 11.1 and 13.4 compression
[Re: Cab_Burge]
#1592012
03/12/14 05:43 PM
03/12/14 05:43 PM
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Joined: Jan 2003
Posts: 11,711
Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,711
Portage,michigan
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Few years back I made some changes and will post the results, but I had several variables thrown in the mix. 70 Duster. I went from a 416 to a 422. both were run in the same car, with same heads, headers, intake, carb, convertor and transmission. Did swap from Erson rocker gear to Jesel. There were two differences, went from a 260/266 600 lift flat tappet, to a 273/280 700 lift roller. The other change was going from about 11.5 compression to 13.3 compression. Car went from best of 10.38 at 128 and change, to 9.85 at almost 135. This was using w5 heads. I know the roller helped a good bit but I feel like the compression did as well. Unsure if going from the 4.07 bore 416 to the 4.100 bore 422 impacted things much at all. I noticed the convertor( same one for both, never had it re adjusted) went from flashing 5200 ish to about 5500. The new owner has now bumped the compression up past 14 to 1, run a more aggressive lobe roller that is about 276@50, and taken about 100 pounds out of the car( he is 100 pounds smaller than me..lol) And has now been 9.62 at almost 140. So cam and compression keep picking the car up, the 100 pounds doesn't account for the almost 5mph gain he has seen. The OP is a whole lot smarter than me, but my guess is throwing camshaft at the car in correct tandem with more compression and a workable convertor will show gains, but likely diminishing as you get compression way up there.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam
Best so far, 10.40 @127 1/4
1.41 best 60 foot
6.60 at 103.90 1/8
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Re: HP difference between 11.1 and 13.4 compression
[Re: B3422W5]
#1592013
03/12/14 05:58 PM
03/12/14 05:58 PM
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Joined: Feb 2005
Posts: 20,174
PA.
pittsburghracer
OP
"Little"John
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OP
"Little"John
Joined: Feb 2005
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PA.
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That's what I like to hear. I'm going up over 2 points compression, 550 lift solid to 660 plus lift roller, 35 plus cfm, much better Indy intake, and from a 750 pump gas carb to a dominator (race gas) and 850 alcohol carb. Best this year was a 10.06@130mph on pump gas 93. Still going with same cubic inch (408)
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: HP difference between 11.1 and 13.4 compression
[Re: B3422W5]
#1592015
03/12/14 06:21 PM
03/12/14 06:21 PM
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Joined: Feb 2005
Posts: 20,174
PA.
pittsburghracer
OP
"Little"John
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OP
"Little"John
Joined: Feb 2005
Posts: 20,174
PA.
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Quote:
Quote:
That's what I like to hear. I'm going up over 2 points compression, 550 lift solid to 660 plus lift roller, 35 plus cfm, much better Indy intake, and from a 750 pump gas carb to a dominator (race gas) and 850 alcohol carb. Best this year was a [Email]10.06@130mph[/Email] on pump gas 93. Still going with same cubic inch (408)
if you get it sorted out well, I bet it picks up 4 or 5 tenths, possibly even a hair more
I forgot...  ...did go with a lighter ring pack on the 422 as well...but used same header evac as on the 416, no vacuum pump on either motor.
Btw.... I at one time tried an Indy intake over the Victor W2 Brett had modified for use with the W5 heads...didn't see a thing...it was Bretts old intake. Think I remember him telling me he didn't see anything either, but as he had done up an Indy already, he sold me the Victor he had as his spare
I have a Super Victor on my Edelbrock heads now and its getting replaced with the Indy intake that is shaping up real nice. Before I pull the engine out from last year I plan on testing it with the better heads, Indy intake, either a 630 lift solid or maybe a roller cam Matt has laying here but still leave it on pump gas. Just a little itch I have to scratch before jumping the compression up. 
1970 Duster
Edelbrock headed 408
5.984@112.52
422 Indy headed small block
5.982@112.56 mph
9.42@138.27
Livin and lovin life one day at a time
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Re: HP difference between 11.1 and 13.4 compression
[Re: qwkmopardan]
#1592020
03/12/14 11:13 PM
03/12/14 11:13 PM
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Joined: Jan 2003
Posts: 11,711
Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,711
Portage,michigan
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Quote:
The better flowing heads should pick up 1.5 to 2 hp per cfm gained. The roller cam could help or not. Twice I have switched from customer picked solid roller to good grind solid flat tappet cam and car went quicker. Also quit breaking rocker arms and shafts and pushrods. If everything that we have bought, that was supposed to make our cars faster, actually did, we would all have 6 second cars.
There is no way an optimal roller cam won't outperform an optimal flat tappet, all other factors the same. If your results have differed from that, the above conditions couldnt have been met.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam
Best so far, 10.40 @127 1/4
1.41 best 60 foot
6.60 at 103.90 1/8
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Re: HP difference between 11.1 and 13.4 compression
[Re: qwkmopardan]
#1592022
03/14/14 04:48 PM
03/14/14 04:48 PM
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Joined: Oct 2004
Posts: 8,165
Left Coast
BobR
master
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master
Joined: Oct 2004
Posts: 8,165
Left Coast
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Quote:
There is no way an optimal roller cam won't outperform an optimal flat tappet, all other factors the same. If your results have differed from that, the above conditions couldnt have been met.
Sounds like a good test for myth busters.
I don't have a roller cam in none of my junk, except stock 09 challenger. How much faster do you think a 3080# Demon can go with a stroker 360 with production heads? Mine has been in the 9.60s with a STX-22, [276* .590" lift] Racer Brown solid flat tappet and has 1800 passes on it with zero valve train issues. Same cam you could get in the early 70s. Same camshaft in my lebaron at 2560# but in a 512 c.i. stroker BB with a set of hand ported INDY SRs. 8.50s at 158mph. That is 825 horsepower with INDY SR heads and a flat tappet camshaft. Even if I could pick up a tenth with a roller I would not do it because of the added cost and maintenance. The flat tappet cam/lifters and springs cost just a little more than a decent set of springs for a roller cam and flat tappet stuff will outlast the roller lifters and springs 3 to 1.
There is a reason the springs cost more. They have to be a lot better to cope with the increased ramp rates and higher lift. There is NO QUESTION that the roller design is better than the flat tappet design.
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Re: HP difference between 11.1 and 13.4 compression
[Re: BobR]
#1592023
03/14/14 09:44 PM
03/14/14 09:44 PM
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Joined: Jan 2003
Posts: 9,999
Frostbitefalls MN (Rocky&Bullw...
gregsdart
master
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master
Joined: Jan 2003
Posts: 9,999
Frostbitefalls MN (Rocky&Bullw...
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It looks like you increased the whole induction system by a bunch, THEN added the squeeze. I would expect this motor to really rock compared to the first configuration.
Rollercam big+
headflow and manifold 35 cfm+
With the effect of dynamic compression, the motor would see a bigger change than the static 2.3 point increase.
A minimum of 50 hp, maybe 100? It will be great to here how it runs!
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: HP difference between 11.1 and 13.4 compression
[Re: pittsburghracer]
#1592024
03/16/14 05:17 PM
03/16/14 05:17 PM
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Joined: Oct 2007
Posts: 4,206
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,206
New York
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The extra power will be a greater percentage with poor heads.
If you still have "dynamic compression" above 3,000 RPM your cam is too big.
Boffin Emeritus
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and there will no need for cool down in between runs needed you won't even need to leave the fan running.
