Whats the Max Compresion you can run on 87 Octane?
12-14-2007, 11:18 AM
#11
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Thanks MRHORSEPOWER1!
I have a stainless marine crossover/Tstat kit with larg oil cooler and a high flow 140deg thermostat with four 1/8" holes in it from the supercharged motors. But I did not have an oil thermostat.
I used to get a lot of moisture in those motors if I did not run them very long and very hard.
So than plan would be to get rid of the thermostat and put in a 1/2" restrictive washer and a oil Tstat?
I have a stainless marine crossover/Tstat kit with larg oil cooler and a high flow 140deg thermostat with four 1/8" holes in it from the supercharged motors. But I did not have an oil thermostat.
I used to get a lot of moisture in those motors if I did not run them very long and very hard.
So than plan would be to get rid of the thermostat and put in a 1/2" restrictive washer and a oil Tstat?
12-14-2007, 11:37 AM
#12
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12-14-2007, 12:00 PM
#13
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I've seen the article before and re-read it earlier today. I just went thru it again- saw only one reference to aluminum heads and it was how they transfer heat from the valve seats. No reference to their effect on preventing detonation.
12-14-2007, 02:13 PM
#14
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THANKS for all the help!!
Now I just hope the Bigger NA motor will not make me miss my blowers!
Does it seem reasonable to be able to get 650-700hp out of a N/A 548 at 5500 max rpm with 87 octane and these specs:
Chevy MK IV BOW TIE Block bored to 4.530
Scat 4340 4.250 Crank
Scat 4340 H-beam rods 6.385
JE/SRP flat top pistons 9.5:1
Crane roller cam P/N 139021 with roller rockers too
Chevy BOWTIE 861 casting aluminum heads with 2.25 & 1.88 valves with some porting on the runners and chambers.
Dart intake with some mild porting and matching
Holley 1050 dominator marine carb
Thunder bolt IV ing with MSD box set to 34 max
Keith Eickert Cast Aluminum Exhaust Headers
BIG oil cooler and stainless marine cross over
Any thoughts from the experts would be great, that is my plan so far.
Now I just hope the Bigger NA motor will not make me miss my blowers!
Does it seem reasonable to be able to get 650-700hp out of a N/A 548 at 5500 max rpm with 87 octane and these specs:
Chevy MK IV BOW TIE Block bored to 4.530
Scat 4340 4.250 Crank
Scat 4340 H-beam rods 6.385
JE/SRP flat top pistons 9.5:1
Crane roller cam P/N 139021 with roller rockers too
Chevy BOWTIE 861 casting aluminum heads with 2.25 & 1.88 valves with some porting on the runners and chambers.
Dart intake with some mild porting and matching
Holley 1050 dominator marine carb
Thunder bolt IV ing with MSD box set to 34 max
Keith Eickert Cast Aluminum Exhaust Headers
BIG oil cooler and stainless marine cross over
Any thoughts from the experts would be great, that is my plan so far.
12-14-2007, 02:17 PM
#15
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What I thought was in that artilce is in a different one. It claims aluminum heads w/ their superior heat transfer can allow for 0.5 increase in CR vs iron.
12-14-2007, 04:45 PM
#16
Geronimo36
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If your N/A , yes I have run 9.5:1 compression on 87 octane with aluminum heads. I would not run a thermostat for the water, keep the timing at 34 total, and it would be wise to run a thermostatic oil filter assembly to build proper oil temps and keep the engine free of moisture .
So anyway....hearing the horror stories of people this past year with the fuels...I decided to go up one point in the jets on my secondaries....just to be safe...
What are your thoughts on the crappy fuel we've been getting and the increased amount of detonation that's been ocouring across the board? Is it from fuels sitting too long or the alcohol A/F ratio theory?
12-14-2007, 06:59 PM
#17
I use 93 but have that fear of getting cought out somewhere and need fuel ...
I am running MIV 496's with Edelbrock Aluminum heads at 9.5 .... I do have an issue with oil temps ... I cannot get them above 180-190 I am using the KE remote thermostats and HP style 3x18 coolers ... I have checked plumbing several times and cannot figure where the problem is .. I am measuring the temp at the thermosat ....there is a spare port and we tapped into the direct flow of oil inside the thermostat ..routing is block to oil filter to thermostat ...then either to cooler or block ....
Also I am running a 142* stat in one motor and no stat in the other ( testing) .... they run pretty much the same water temps ...150 .... only difference is the motor without the water stat is slower to get the oil temp up to the 160-180 range ... I am having milkshake issues in the top end ....
sorry to hijack but seems on the topic ... Also when I get the chance to tap Mr HP .... I do it ....
12-14-2007, 08:04 PM
#18
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Thread Starter
I don't think you are hijacking, with every question I think we are all learning something. I was hopeing to get a conformation on my expected HP from the combo I listed. With the 496s you have any idea how much power you are making? I have the old dyno sheet to my 468 blower motors and they were 663 & 672. I liked the power and was hopeing to not loose and speed going N/A.
12-14-2007, 08:23 PM
#19
I don't think you are hijacking, with every question I think we are all learning something. I was hopeing to get a conformation on my expected HP from the combo I listed. With the 496s you have any idea how much power you are making? I have the old dyno sheet to my 468 blower motors and they were 663 & 672. I liked the power and was hopeing to not loose and speed going N/A.
12-14-2007, 08:34 PM
#20
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I ran low octane fuel in my 582's with 9.89:1 compresion ratio.
Mine were Iron heads, but aluminum does help a lot. It does keep the temp of the exhaust valves lower.
Keep the total timing down 32-34 incase you get some bad gas.
I sometimes filled up with 93 just to keep it mixed up and keep the low test gas up to where it was supposed to be.
You'll be fine doing wha you are doing and with the right cam you can get way more than 650hp out of a 540.
Good luck with your project.
Mine were Iron heads, but aluminum does help a lot. It does keep the temp of the exhaust valves lower.
Keep the total timing down 32-34 incase you get some bad gas.
I sometimes filled up with 93 just to keep it mixed up and keep the low test gas up to where it was supposed to be.
You'll be fine doing wha you are doing and with the right cam you can get way more than 650hp out of a 540.
Good luck with your project.
