Can you make 500+ HP with a 8.5:1 compression ratio?

nba1341 · May 3rd, 2007, 01:17 AM

I am not sure how compression ratios work but I know that low octane fuel is a lot cheaper than premium

I am going to be building an engine in the coming months and was wondering if you could build a high horsepower engine running on low octane gas?

Is this going to be hard? I am talking just engine here not s/c, etc.

and Ive been told 9.0:1 will still require 93 octane gas??? Is this true?

matrixpuba · May 3rd, 2007, 02:12 AM

what will be the engine displacment?

nba1341 · May 3rd, 2007, 02:19 AM

351 windsor stroked to 393 using a chp kit

matrixpuba · May 3rd, 2007, 04:16 AM

i dont see it happen on 87 oct.

TurboLX · May 4th, 2007, 05:07 PM

Originally Posted by matrixpuba

i dont see it happen on 87 oct.

not at all, you will have some SERIOUS detonation

TurboLX · May 4th, 2007, 05:07 PM

which is bad and causes piston slap

matrixpuba · May 4th, 2007, 05:27 PM

or a collapsed ring land

Darrell · May 4th, 2007, 07:59 PM

Naturally aspirated and 393 cubic inches, possible but not cheap. More cubes or a blower would help. 9:1 will run fine on 87 octane. Detonation doesn't cause piston slap. Excessive piston to wall clearance does.

matrixpuba · May 5th, 2007, 08:21 AM

i think running 87 oct. with 393 cubes you will have to cut back the timing and wont reach the 500 mark.

Darrell · May 5th, 2007, 10:28 PM

Originally Posted by matrixpuba

i think running 87 oct. with 393 cubes you will have to cut back the timing and wont reach the 500 mark.

Cubic inches has nothing at all to do with octane required. Compression, timing, power adders, cylinder head material and sometimes cam overlap do.

matrixpuba · May 5th, 2007, 11:35 PM

im not claiming that cubes has anything to do with octane requirements. im stating that with 373 cubes, and enough compression to make the 500 mark, you would have to dial back the timing to keep from detonating which would make him shy of 500. now on 93 octane it might resist knock enough to reach 500.

Darrell · May 6th, 2007, 05:22 AM

Originally Posted by matrixpuba

im not claiming that cubes has anything to do with octane requirements. im stating that with 373 cubes, and enough compression to make the 500 mark, you would have to dial back the timing to keep from detonating which would make him shy of 500. now on 93 octane it might resist knock enough to reach 500.

You can make 500 hp with a 393 and 9:1 compression and 87-89 octane.

May 3rd, 2007, 01:17 AM	#1
nba1341 Banned 1965 Mustang Fastback Join Date: Apr 2007 Location: Los Angeles, Cal Posts: 24,982 Posts: 2,193	Can you make 500+ HP with a 8.5:1 compression ratio? I am not sure how compression ratios work but I know that low octane fuel is a lot cheaper than premium I am going to be building an engine in the coming months and was wondering if you could build a high horsepower engine running on low octane gas? Is this going to be hard? I am talking just engine here not s/c, etc. and Ive been told 9.0:1 will still require 93 octane gas??? Is this true?

May 3rd, 2007, 02:12 AM	#2
matrixpuba Hardcore Enthusiast Join Date: Sep 2006 Location: tennessee Posts: 2,379	what will be the engine displacment? __________________ http://img.photobucket.com/albums/v2.../matrixsig.jpg

May 3rd, 2007, 04:16 AM	#4
matrixpuba Hardcore Enthusiast Join Date: Sep 2006 Location: tennessee Posts: 2,379	i dont see it happen on 87 oct. __________________ http://img.photobucket.com/albums/v2.../matrixsig.jpg

May 4th, 2007, 05:07 PM	#6
TurboLX I Post Entirely Way Too Much 1990 Mustang LX Turbo 8.67@165.91 mph Join Date: Oct 2006 Location: Hidden In NY Posts: 8,471	which is bad and causes piston slap __________________ Wiring Diagrams, TSB's, OBD Service Codes and Engine Diagrams Available. PM For Info Myspace *Small Block Posse*

May 4th, 2007, 05:27 PM	#7
matrixpuba Hardcore Enthusiast Join Date: Sep 2006 Location: tennessee Posts: 2,379	or a collapsed ring land __________________ http://img.photobucket.com/albums/v2.../matrixsig.jpg

May 3rd, 2007, 02:19 AM	#3
nba1341 Banned 1965 Mustang Fastback Join Date: Apr 2007 Location: Los Angeles, Cal Posts: 24,982 Posts: 2,193	351 windsor stroked to 393 using a chp kit

May 4th, 2007, 07:59 PM	#8
Darrell MM Ninjas! 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: Fond du Lac, Wisconsin Posts: 6,497	Naturally aspirated and 393 cubic inches, possible but not cheap. More cubes or a blower would help. 9:1 will run fine on 87 octane. Detonation doesn't cause piston slap. Excessive piston to wall clearance does. __________________ Racing in memory of Dave Bandt 11/19/69 - 3/23/08 "he's traded his wheels for wings" Professor of Natural Aspiration Thanks to: Artie at Trick Flow, Dave at Team Z Motorsports, Brian at Total Engine Airflow and Harold at Furo Racecraft

May 5th, 2007, 08:21 AM	#9
matrixpuba Hardcore Enthusiast Join Date: Sep 2006 Location: tennessee Posts: 2,379	i think running 87 oct. with 393 cubes you will have to cut back the timing and wont reach the 500 mark. __________________ http://img.photobucket.com/albums/v2.../matrixsig.jpg

May 5th, 2007, 11:35 PM	#11
matrixpuba Hardcore Enthusiast Join Date: Sep 2006 Location: tennessee Posts: 2,379	im not claiming that cubes has anything to do with octane requirements. im stating that with 373 cubes, and enough compression to make the 500 mark, you would have to dial back the timing to keep from detonating which would make him shy of 500. now on 93 octane it might resist knock enough to reach 500. __________________ http://img.photobucket.com/albums/v2.../matrixsig.jpg

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