bigger or smaller cu if going to max out turbo
01-20-2008, 09:07 AM
#1
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bigger or smaller cu if going to max out turbo which would be better for a s70 if planing on make as much power as possible
stock cu 365 4.00 bore 3.625 stroke
310 cu 4.06 bore and 3.0 stroke
both would be at least 11 to 1
both would have afr's
stock cu 365 4.00 bore 3.625 stroke
310 cu 4.06 bore and 3.0 stroke
both would be at least 11 to 1
both would have afr's
01-20-2008, 11:58 AM
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need to max out turbo is for class racing recorded in the class is 8.99 with 360 cu no weight break for smaller cu just wondering if there is an advantage to useing a small cu because limited on turbo size
01-20-2008, 12:51 PM
#5
Turbo motors aren't like SC, nitrous, or NA motors. The compressor gets more efficient at higher pressure ratios. You have to run a small engine to get the compressor to its efficient range. That, in turn, reduces exhaust backpressure required and increases power.
The typical 350+ cid V-8 running my T76GTS makes 850 rwhp.
The typcial 180 cid I-6 running the same T76GTS makes 1000+ rwhp.
But. . . you have to be willing to run high boost to get the advantage. Like 30++ psi. However, if you're trying to get max power at low boost (e.g. pump gas), then go with bigger cubes, which is what I did.
Mike
The typical 350+ cid V-8 running my T76GTS makes 850 rwhp.
The typcial 180 cid I-6 running the same T76GTS makes 1000+ rwhp.
But. . . you have to be willing to run high boost to get the advantage. Like 30++ psi. However, if you're trying to get max power at low boost (e.g. pump gas), then go with bigger cubes, which is what I did.
Mike
01-20-2008, 05:45 PM
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Turbo motors aren't like SC, nitrous, or NA motors. The compressor gets more efficient at higher pressure ratios. You have to run a small engine to get the compressor to its efficient range. That, in turn, reduces exhaust backpressure required and increases power.
The typical 350+ cid V-8 running my T76GTS makes 850 rwhp.
The typcial 180 cid I-6 running the same T76GTS makes 1000+ rwhp.
But. . . you have to be willing to run high boost to get the advantage. Like 30++ psi. However, if you're trying to get max power at low boost (e.g. pump gas), then go with bigger cubes, which is what I did.
Mike
The typical 350+ cid V-8 running my T76GTS makes 850 rwhp.
The typcial 180 cid I-6 running the same T76GTS makes 1000+ rwhp.
But. . . you have to be willing to run high boost to get the advantage. Like 30++ psi. However, if you're trying to get max power at low boost (e.g. pump gas), then go with bigger cubes, which is what I did.
Mike
limited to 70mm vp 116 gas
it will make as much boost as it make
how much compression is to much in this appication
heads up as fast as can go
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01-20-2008, 08:16 PM
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Have 6.0l block with roller cam bearing 4.003 ready to go
Have eagle H-beam rods with l19 bolt
Have 4.8 crank 10 10
afr heads 205 lots of work flowed 323 at .550 max lift for class
fast 90mm intake worked 80mm tb
how much compression (11 plus?)
s70 in s76 housing with 1.3 AR and t6 flange
would this be good combo or to many cu
01-20-2008, 08:19 PM
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I wonder what a 4.8 or 5.3 would be like with a PT74 on it. I say go smaller on the displacement!!! I think you would be happier, as mentioned with a 4.8 and that turbo. Just my .02 cents. Take care.
Jim C.
Jim C.
01-20-2008, 08:28 PM
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4.8 crankshaft in 6.0l block makes 330 cu
Have 6.0l block with roller cam bearing 4.003 ready to go
Have eagle H-beam rods with l19 bolt
Have 4.8 crank 10 10
afr heads 205 lots of work flowed 323 at .550 max lift for class
fast 90mm intake worked 80mm tb
how much compression (11 plus?)
s70 in s76 housing with 1.3 AR and t6 flange
would this be good combo or to many cu
Have 6.0l block with roller cam bearing 4.003 ready to go
Have eagle H-beam rods with l19 bolt
Have 4.8 crank 10 10
afr heads 205 lots of work flowed 323 at .550 max lift for class
fast 90mm intake worked 80mm tb
how much compression (11 plus?)
s70 in s76 housing with 1.3 AR and t6 flange
would this be good combo or to many cu
01-20-2008, 10:24 PM
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what about 3.00 stroke and 4.00 bore 302 cu
how much compression
01-21-2008, 09:12 AM
#15
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I'd be curious to see how it would do with the 6.0 block and the 4.8 3.27 stroke crankshaft. I know that folks running in restricted classes will typically run more compression than street cars, but is the average 11:1 in that class? Sounds like that NMRA class.
01-21-2008, 12:10 PM
#16
01-21-2008, 07:41 PM
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what do you think?
think this will be faster than 4.0 bore 3.625 stroke 6.0L
most people were running 9.0 to 10.0 to 1 on the 72mm last year
01-22-2008, 04:59 AM
#19
I was just thinking, wouldn't a longer stroke smaller bore combo allow more static compression than a large bore small stroke combo? I'm still not sure if the difference would overcome the extra piston speed problems, but I thought it would be food for thought anyway.
