2270 build, 2270 compression question |
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2270 build, 2270 compression question |
Alapone |
Jul 16 2018, 07:26 PM
Post
#21
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Member Group: Members Posts: 108 Joined: 4-April 13 From: Nj Member No.: 15,734 Region Association: None |
Hey guys,
I am having a 2270 built, 78mmx96mm. We are using the 163/86b webcam and 2.0l heads. Dellorto 45s and msds headers. I am trying to decide on the right compression. The build is aimed at aggresive street use. I want to have as much power as possible and not have to run an external oil cooler or have any problems with detonation on 93/4 octane gas. I have heard anything from 8.5:1 to 9.5:1. Please let me know your thoughts. Thanks, Andrew |
McMark |
Jul 17 2018, 05:30 AM
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#22
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
I'll throw my votes in...
8.5:1 - Very safe on regular gas. 8.7:1 - Still safe, but starting to push things. Regular gas is probably still okay. 9.0:1 - More power, but you gotta pay attention for heat and detonation are starting to become serious factors. Premium fuel would be best. 9.3:1 - This level can't use the word safe at all. You must shed the heat and you must be very conscious of detonation/pinging. 9.5:1 - You better know what you're doing, at all times. This is no longer a jump in a drive motor, this is a motor that you must constantly be listening to and feeling. Above premium fuel is necessary. |
troth |
Jul 17 2018, 06:18 AM
Post
#23
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Member Group: Members Posts: 153 Joined: 17-August 16 From: CT/WA Member No.: 20,305 Region Association: None |
I'll throw my votes in... 8.5:1 - Very safe on regular gas. 8.7:1 - Still safe, but starting to push things. Regular gas is probably still okay. 9.0:1 - More power, but you gotta pay attention for heat and detonation are starting to become serious factors. Premium fuel would be best. 9.3:1 - This level can't use the word safe at all. You must shed the heat and you must be very conscious of detonation/pinging. 9.5:1 - You better know what you're doing, at all times. This is no longer a jump in a drive motor, this is a motor that you must constantly be listening to and feeling. Above premium fuel is necessary. Mark, for future reference and general knowledge... Could you please clarify what you mean by regular vs. premium gas? 87ish octane low grade pump gas for regular 91ish premium pump gas for premium? Above premium = 95+ race fuel you get at the track? I've only ever put the Shell V-Power in my car. I'm certain it's overkill for a stock 1.8. |
ChrisFoley |
Jul 18 2018, 08:51 AM
Post
#24
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I am Tangerine Racing Group: Members Posts: 7,958 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None |
I'll throw my votes in... 8.5:1 - Very safe on regular gas. 8.7:1 - Still safe, but starting to push things. Regular gas is probably still okay. 9.0:1 - More power, but you gotta pay attention for heat and detonation are starting to become serious factors. Premium fuel would be best. 9.3:1 - This level can't use the word safe at all. You must shed the heat and you must be very conscious of detonation/pinging. 9.5:1 - You better know what you're doing, at all times. This is no longer a jump in a drive motor, this is a motor that you must constantly be listening to and feeling. Above premium fuel is necessary. Mark, for future reference and general knowledge... Could you please clarify what you mean by regular vs. premium gas? 87ish octane low grade pump gas for regular 91ish premium pump gas for premium? Above premium = 95+ race fuel you get at the track? I've only ever put the Shell V-Power in my car. I'm certain it's overkill for a stock 1.8. I recommend mid-grade (89 octane) gasoline for all stock 914-4 engines. 87 octane may ping under load going up hills. Premium is a waste of money, and it contains less energy than mid. |
Mblizzard |
Jul 18 2018, 09:12 AM
Post
#25
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Advanced Member Group: Members Posts: 3,033 Joined: 28-January 13 From: Knoxville Tn Member No.: 15,438 Region Association: South East States |
I'll throw my votes in... 8.5:1 - Very safe on regular gas. 8.7:1 - Still safe, but starting to push things. Regular gas is probably still okay. 9.0:1 - More power, but you gotta pay attention for heat and detonation are starting to become serious factors. Premium fuel would be best. 9.3:1 - This level can't use the word safe at all. You must shed the heat and you must be very conscious of detonation/pinging. 9.5:1 - You better know what you're doing, at all times. This is no longer a jump in a drive motor, this is a motor that you must constantly be listening to and feeling. Above premium fuel is necessary. Mark, for future reference and general knowledge... Could you please clarify what you mean by regular vs. premium gas? 87ish octane low grade pump gas for regular 91ish premium pump gas for premium? Above premium = 95+ race fuel you get at the track? I've only ever put the Shell V-Power in my car. I'm certain it's overkill for a stock 1.8. I recommend mid-grade (89 octane) gasoline for all stock 914-4 engines. 87 octane may ping under load going up hills. Premium is a waste of money, and it contains less energy than mid. The only reason I use Premium is that at times gas stations cross dump thier fuels. Most often the low grade into the mid. So it is more likely you get a lot of 87 being sold as mid. |
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