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Can someone double check some final comp numbers #2617089
02/04/19 11:32 PM
02/04/19 11:32 PM
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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I went from 93 pump gas builds to alcohol type builds so final compression numbers weren't very important to me but I'm almost ready to install my 572 and gotta figure out what race gas I will be needing for this build.

Engine specs
572 cubic inch. 4.500 bore-4.500 stroke
pistons. Nitrous inverted dome -24cc
Cometic head gasket 4.540 bore .060 thick
was told its 15.92cc
B1 head chamber 67.5cc

Using an online calculator I'm getting 107.4cc
11.91 compression.


Last edited by pittsburghracer; 02/04/19 11:32 PM.

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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617098
02/04/19 11:40 PM
02/04/19 11:40 PM
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Posts: 3,036
bean town ....Ca
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WHITEDART Offline
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bean town ....Ca
I love the oxygenated fuel.. like q16 or something along that line. More than likely you may be able to get away with some C12 depends on the budget you have set for your project


In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb
Re: Can someone double check some final comp numbers [Re: WHITEDART] #2617101
02/04/19 11:42 PM
02/04/19 11:42 PM
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Posts: 20,116
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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Originally Posted By WHITEDART
I love the oxygenated fuel.. like q16 or something along that line. More than likely you may be able to get away with some C12 depends on the budget you have set for your project




VERY low budget but I will run one higher grade than needed because of the planned nitrous hit. LOL.


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617113
02/04/19 11:56 PM
02/04/19 11:56 PM
Joined: Oct 2011
Posts: 3,036
bean town ....Ca
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WHITEDART Offline
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bean town ....Ca
Originally Posted By pittsburghracer
Originally Posted By WHITEDART
I love the oxygenated fuel.. like q16 or something along that line. More than likely you may be able to get away with some C12 depends on the budget you have set for your project




VERY low budget but I will run one higher grade than needed because of the planned nitrous hit. LOL.
q16 was the fuel of choice in Ultra for the nitrous car

If you tow the car up and back you will be surprised at how little fuel you actually use. Towing up and back. I use less than a half a gallon per pass.. shakes out to be about $10 a run

Last edited by WHITEDART; 02/05/19 02:37 AM.

In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb
Re: Can someone double check some final comp numbers [Re: WHITEDART] #2617117
02/05/19 12:08 AM
02/05/19 12:08 AM
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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I’m a one man show so I will be driving it up and back


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617120
02/05/19 12:24 AM
02/05/19 12:24 AM
Joined: Oct 2004
Posts: 3,097
back in Georgia
dthemi Offline
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dthemi  Offline
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http://www.diamondracing.net/tools/

This is the best one I've used. I've done the actual math to check it in the past, and it's completely accurate.

Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617150
02/05/19 01:32 AM
02/05/19 01:32 AM
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So. Burlington, Vt.
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fast68plymouth Offline
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So. Burlington, Vt.
Assuming zero deck and 1cc for area above the rings, I get 11.82.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617163
02/05/19 02:11 AM
02/05/19 02:11 AM
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baldwinsville new york
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a493demon Offline
pro stock
a493demon  Offline
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That's about where i'm at . ( 11.2 or 11.7 I can't remember ) and I run 116

Re: Can someone double check some final comp numbers [Re: a493demon] #2617166
02/05/19 02:23 AM
02/05/19 02:23 AM
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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PA.
Appreciate the second set of eyes guys. Heck maybe I can run BP93 pump gas with this combo.


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617173
02/05/19 03:39 AM
02/05/19 03:39 AM
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Posts: 19,304
Las Vegas
Al_Alguire Offline
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Las Vegas
I thought 11.9-1 WAS pump gas smile


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617217
02/05/19 10:38 AM
02/05/19 10:38 AM
Joined: Jun 2015
Posts: 310
Northeast Indiana
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73DAD Offline
enthusiast
73DAD  Offline
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Northeast Indiana
Not enough info to calculate CR. Need to know piston to deck.

If its perfectly zero deck, then 11.92 rounded the nearest hundredth.

Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617221
02/05/19 10:40 AM
02/05/19 10:40 AM
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Posts: 3,097
back in Georgia
dthemi Offline
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dthemi  Offline
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back in Georgia
Spraying helps pump gas.

I ran in hot rods pump gas drags in 06 with a 12.8:1 engine, and sprayed 200 at it on pump gas, in summer heat. I ran it later with pump, and sprayed 350 at it. When I'd drive it around on really hot days and load the motor at low rpm, it would ping.

I checked the filter regularly when racing it on pump, and spray, and never saw any signs of damaging detonation.

Re: Can someone double check some final comp numbers [Re: Al_Alguire] #2617227
02/05/19 10:57 AM
02/05/19 10:57 AM
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Posts: 20,116
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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Originally Posted By Al_Alguire
I thought 11.9-1 WAS pump gas smile



Heck that’s the highest compression I’ve had in an engine for over 8 years. Lol. Lots of horsepower left on the table with this engine setting it up for nitrous. These were Jason Dixbys rods and pistons from when he switched over to turbo power.


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617314
02/05/19 02:45 PM
02/05/19 02:45 PM
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Cheswick, PA
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Bob_Spelic Offline
mopar
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at zero deck, I get 11.87. at .020 in the hole I get 11.37 on my home brew spreadsheet calculator.

bob

Re: Can someone double check some final comp numbers [Re: Bob_Spelic] #2617321
02/05/19 02:56 PM
02/05/19 02:56 PM
Joined: Feb 2005
Posts: 20,116
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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Originally Posted By Bob_Spelic
at zero deck, I get 11.87. at .020 in the hole I get 11.37 on my home brew spreadsheet calculator.

bob


Thanks guys. It’s zero deck.


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617333
02/05/19 03:04 PM
02/05/19 03:04 PM
Joined: Feb 2005
Posts: 20,116
PA.
pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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Posts: 20,116
PA.
It probably won't be a very competitive combo but I will get my feet wet with nitrous. Someone said I was scared to go fast so I should be ok going a little slower. LOL.


Untitled by John Cadamore, on Flickr

Untitled by John Cadamore, on Flickr

Untitled by John Cadamore, on Flickr


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2617354
02/05/19 03:54 PM
02/05/19 03:54 PM
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Washington
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madscientist Offline
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Washington
Is that the CR you were shooting for? If so, golden. If not...bummer.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Can someone double check some final comp numbers [Re: madscientist] #2617378
02/05/19 04:57 PM
02/05/19 04:57 PM
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Posts: 20,116
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pittsburghracer Offline OP
"Little"John
pittsburghracer  Offline OP
"Little"John

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Originally Posted By madscientist
Is that the CR you were shooting for? If so, golden. If not...bummer.



I honestly didn’t have a target in mind. I had this engine together with a set of Wiseco pistons as a NA combo. I talked to Vic at Wisco and he recommended only hitting them with 200-250. I had bought a set of nitrous pistons from Jason Dixby when he was switching to turbo power so I used those pistons in this build. I have a Sledgehammer plate system that is good for a 300-700 hit


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




Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2618081
02/07/19 01:11 AM
02/07/19 01:11 AM
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NY
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B1duster Offline
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At zero I get 11.77 on Diamond Pistons calculator

Re: Can someone double check some final comp numbers [Re: pittsburghracer] #2618872
02/08/19 11:09 PM
02/08/19 11:09 PM
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Posts: 4,662
On the parachute mount
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n20mstr Offline
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What cam is in it ? I ask because a nitrous grind that opens the exh really early, would benefit from more compression. Also how much nitrous are you going to use ? Depending on the cam, it might want 13 or more. You know what your doing with an engine, so you'll learn through testing . Also are the chambers softened on your heads ?


....BAD A$$ STREET CAR.....
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