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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Cab_Burge]
#2426939
01/01/18 02:38 AM
01/01/18 02:38 AM
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Joined: Jan 2003
Posts: 5,488
SoCal
Brian Hafliger
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If I'm remembering your shop location correctly it is right at sea level, correct? I have seen the density altitude at Thermal airport(150 Ft. below sea level) be right at 8700 Ft in the mornings in June, I have also raced at the old street races in Indio in March when the D.A. was probably around 1200 Ft.  The motor knows how thick or thin the air is regardless of the Pro Charger, correct If you dyno an engine at sea level, or 5000ft. up, it does not matter...it's called a correction factor. His uncorrected HP on that pull was 895. His car has already run 9.90's in full street trim at 780HP...much faster than some Dusters out there with 750HP BB's....
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Cab_Burge]
#2426941
01/01/18 02:46 AM
01/01/18 02:46 AM
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Joined: Jan 2003
Posts: 5,488
SoCal
Brian Hafliger
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If I'm remembering your shop location correctly it is right at sea level, correct? I have seen the density altitude at Thermal airport(150 Ft. below sea level) be right at 8700 Ft in the mornings in June, I have also raced at the old street races in Indio in March when the D.A. was probably around 1200 Ft. The motor knows how thick or thin the air is regardless of the Pro Charger, correct I am going to ask you nicely to leave my posts alone...I do not need you trying to correct me. This is not your Post, and nothing has been directed at you except for me being stupid enough to actually try and explain something to you.
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Brian Hafliger]
#2427192
01/01/18 03:10 PM
01/01/18 03:10 PM
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Joined: Jan 2003
Posts: 5,488
SoCal
Brian Hafliger
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9 to 1 compression works great with E85 turbo supercharged or whatever. I would not be afraid to do that up to 18 PSI of boost. Use an NGK number 7 spark plug that is non projected as a starting point.
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Uberpube]
#2427545
01/02/18 12:37 AM
01/02/18 12:37 AM
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Joined: Jan 2017
Posts: 274
Granbury TX
Prochargedmopar
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Will it even run/start on e85 with 7.6:1 comp.?
Have you ran it that low before on E?
This is suppose to be a street car with only a few 1/8 or 1/4 blasts a year.
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Prochargedmopar]
#2427730
01/02/18 01:25 PM
01/02/18 01:25 PM
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Granbury TX
Prochargedmopar
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Holy Smokes,
Custom pistons from Diamond?
$1160!!!!!
And they still can’t make them 522g so I would need another rebalance.
Said new materials and machining techology would put them in the upper 400 gram range.
I really don’t want a low comp. laggy/peaky motor in my 3400# car.
hmmmmm
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
73 Dodge Dart Swinger
73 Ford F-100 390/Sniper efi/back to carb
01 Town and Country Limited
08 Dodge 2500 6.7 5" Deleted
02 Mercedes C230K
19 Camry
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: FastmOp]
#2427769
01/02/18 02:31 PM
01/02/18 02:31 PM
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Joined: Jan 2003
Posts: 5,488
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Brian Hafliger
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Less than 9:1 is harder to make power with using E85...it won't like it.
Plug is NGK -7 non projected. Similar to the -8 and -9 but hotter.
Never get a light piston using BOOST!
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Prochargedmopar]
#2427925
01/02/18 06:32 PM
01/02/18 06:32 PM
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Joined: Jan 2017
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Granbury TX
Prochargedmopar
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Local machine shop said both heads done is $162 to deck heads to specified cc of 58.
$75 to mill intake sides.
final compression will be 8.3:1
This may be the way i go.
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
73 Dodge Dart Swinger
73 Ford F-100 390/Sniper efi/back to carb
01 Town and Country Limited
08 Dodge 2500 6.7 5" Deleted
02 Mercedes C230K
19 Camry
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: FastmOp]
#2427926
01/02/18 06:33 PM
01/02/18 06:33 PM
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Granbury TX
Prochargedmopar
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Fail to plan, plan to fail. Yup, I bought the rotating assembly parts 14yrs ago. Just now deciding to use them (this past year collecting more parts) Would have been fine with the magnum heads, 93, and the blower.
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
73 Dodge Dart Swinger
73 Ford F-100 390/Sniper efi/back to carb
01 Town and Country Limited
08 Dodge 2500 6.7 5" Deleted
02 Mercedes C230K
19 Camry
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Prochargedmopar]
#2428027
01/02/18 09:52 PM
01/02/18 09:52 PM
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Brian Hafliger
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Can you afford the loss of P/V clearance? Also, correcting intake face, pushrods?
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Prochargedmopar]
#2428059
01/02/18 11:02 PM
01/02/18 11:02 PM
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Joined: Jan 2008
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Canada
WO23Coronet
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Local machine shop said both heads done is $162 to deck heads to specified cc of 58.
$75 to mill intake sides.
final compression will be 8.3:1
This may be the way i go.
I really think you should just live with it. With boost, 7.5:1 is not that big of a deal. Good lord, every Mopar engine built after ‘72 was around that ratio N/A. You need the deck thickness in the heads to deal with the boost. I really don’t understand why you’re so twisted up about this
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: WO23Coronet]
#2428077
01/02/18 11:33 PM
01/02/18 11:33 PM
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Joined: Jan 2017
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Granbury TX
Prochargedmopar
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I’m sure you’ll be fine since you’re going with boost. Not optimal but you should really be able to crank the boost to it. Once boost hits it won’t be laggy at all Because from what i understand after google searching e85 requires a high compression ratio. And can also run with a much higher compression increasing efficiency. If this was race only I’d get the next size up turbo and have at it.
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
73 Dodge Dart Swinger
73 Ford F-100 390/Sniper efi/back to carb
01 Town and Country Limited
08 Dodge 2500 6.7 5" Deleted
02 Mercedes C230K
19 Camry
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Brian Hafliger]
#2428079
01/02/18 11:35 PM
01/02/18 11:35 PM
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Granbury TX
Prochargedmopar
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Can you afford the loss of P/V clearance? Also, correcting intake face, pushrods? Yes, I’ve only got a .505 lift cam 230/240. One of the last items to purchase for assembly is pushrods.
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
73 Dodge Dart Swinger
73 Ford F-100 390/Sniper efi/back to carb
01 Town and Country Limited
08 Dodge 2500 6.7 5" Deleted
02 Mercedes C230K
19 Camry
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Prochargedmopar]
#2428087
01/02/18 11:47 PM
01/02/18 11:47 PM
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Joined: Jan 2003
Posts: 5,488
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Brian Hafliger
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I can sell you some CP bullet series pistons and rings for less than that. Changing pistons is THE only way to go, because you really need to leave the heads unmilled.
9:1 is really where you should start....
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Prochargedmopar]
#2428088
01/02/18 11:49 PM
01/02/18 11:49 PM
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Brian Hafliger
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Also, what are your engine specs...like crank, rods, cam, etc....?
Brian Hafliger
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Re: Higher compression ratio options when starting with 7.5:1?
[Re: Brian Hafliger]
#2428350
01/03/18 02:57 PM
01/03/18 02:57 PM
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Joined: Jan 2017
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Granbury TX
Prochargedmopar
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I can sell you some CP bullet series pistons and rings for less than that. Changing pistons is THE only way to go, because you really need to leave the heads unmilled.
9:1 is really where you should start.... How much? Need comp. height of 1.545 Chevy .927 pin dia. Valve reliefs And a weight of 522 grams Diamond tech said his pistons because of new technology and machining processes would be lighter. I’d prefer not to rebalance. 6cc reliefs with flat top would be perfect.
Last edited by prochargedmopar; 01/03/18 02:58 PM.
"Old" member Registered: Sep 2001
Lost my credentials, I'm Back!! LOL
71 Ply Satellite Procharged
73 Dodge Dart Swinger
73 Ford F-100 390/Sniper efi/back to carb
01 Town and Country Limited
08 Dodge 2500 6.7 5" Deleted
02 Mercedes C230K
19 Camry
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