Too Much Compression?
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,130
Likes: 106
From: laingsburg MI
2020 C3 of the Year Finalist - Modified
Too Much Compression?
I am thinking of having my heads angle milled this winter, to bring my compression to at least 12:1 to a max of 13:1. This is a street strip car that is at 11:1 now, and is fine on 94 sunoco on the street. I do run 50% race gas mix, but don't need to. Any thoughts on if this compression will make my car too cranky for round town driving?
383 6" rods, flat tops, aluminum heads. good sized cam to bleed of cylinder pressure, good cooling system ect. Thanks for sharing.
383 6" rods, flat tops, aluminum heads. good sized cam to bleed of cylinder pressure, good cooling system ect. Thanks for sharing.
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
I don't see how you can or don't have to run more than 94 on what you have??? 
If you go higher your going to need more octane- if you consider race gas streetable or the range limit it produces then its streetable.
To my understanding if your running 11:1 or is it 11.25:1? you don't have the option of low octane unless the car is detuned, retarded timing.
94 octane is low octane.
I'm just guessing but I would think if you mixed 50% race stuff into 94 you could advance the timing and get more power.
If you go higher your going to need more octane- if you consider race gas streetable or the range limit it produces then its streetable.To my understanding if your running 11:1 or is it 11.25:1? you don't have the option of low octane unless the car is detuned, retarded timing.
94 octane is low octane.
I'm just guessing but I would think if you mixed 50% race stuff into 94 you could advance the timing and get more power.
Race Director
Joined: Apr 2000
Posts: 17,673
Likes: 199
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Just changing the CR will not do much, one point might get you 2%. CR should be dictated by cam, heads and what gas you can get. If you want to bump up the CR it should be done with a cam swap to make any significant gains. 
:
Here is one of the best articles I have read on the subject, it might give you some ideas.
http://www.popularhotrodding.com/eng...power_squeeze/
:Here is one of the best articles I have read on the subject, it might give you some ideas.
http://www.popularhotrodding.com/eng...power_squeeze/
Last edited by MotorHead; Jul 17, 2005 at 10:26 PM.
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,130
Likes: 106
From: laingsburg MI
2020 C3 of the Year Finalist - Modified
Originally Posted by Techno
I don't see how you can or don't have to run more than 94 on what you have??? If you go higher your going to need more octane- if you consider race gas streetable or the range limit it produces then its streetable.
To my understanding if your running 11:1 or is it 11.25:1? you don't have the option of low octane unless the car is detuned, retarded timing.
94 octane is low octane.
I'm just guessing but I would think if you mixed 50% race stuff into 94 you could advance the timing and get more power.
If you go higher your going to need more octane- if you consider race gas streetable or the range limit it produces then its streetable.To my understanding if your running 11:1 or is it 11.25:1? you don't have the option of low octane unless the car is detuned, retarded timing.
94 octane is low octane.
I'm just guessing but I would think if you mixed 50% race stuff into 94 you could advance the timing and get more power.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Don't waste money on small heads like your Edelbrock. Motorhead tried to explain that the additional power gain going from 11.2 to 13 is minimal. I ran a 383 with 11.2 for 20,000 miles and never put anything, but our 91 octane in it
If you want more power the biggest gain would be to purchase heads that flow over 300 cfm intake.
Actually your going to come the same conclusion that I did. You can spend lots of money and turn your 383 7500 rpm and you still just have a 383 ci. Sell it to someone else and start over with a 406+ ci motor. the 427 - 454 small blocks are becoming very common.
If you want more power the biggest gain would be to purchase heads that flow over 300 cfm intake.
Actually your going to come the same conclusion that I did. You can spend lots of money and turn your 383 7500 rpm and you still just have a 383 ci. Sell it to someone else and start over with a 406+ ci motor. the 427 - 454 small blocks are becoming very common.
Thread Starter
Burning Brakes
Joined: Jun 2005
Posts: 1,130
Likes: 106
From: laingsburg MI
2020 C3 of the Year Finalist - Modified
Originally Posted by gkull
Don't waste money on small heads like your Edelbrock. Motorhead tried to explain that the additional power gain going from 11.2 to 13 is minimal. I ran a 383 with 11.2 for 20,000 miles and never put anything, but our 91 octane in it
If you want more power the biggest gain would be to purchase heads that flow over 300 cfm intake.
Actually your going to come the same conclusion that I did. You can spend lots of money and turn your 383 7500 rpm and you still just have a 383 ci. Sell it to someone else and start over with a 406+ ci motor. the 427 - 454 small blocks are becoming very common.
If you want more power the biggest gain would be to purchase heads that flow over 300 cfm intake.
Actually your going to come the same conclusion that I did. You can spend lots of money and turn your 383 7500 rpm and you still just have a 383 ci. Sell it to someone else and start over with a 406+ ci motor. the 427 - 454 small blocks are becoming very common.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,444
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
My in the storage box 383 has Dart 227cc heads on it and a solid roller cam with 236/244 112 lc installed 4 degrees retarded to help it produce more power over 7000 rpm
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