Which is better... 4.20x3.662 or 4.0x4.0
06-03-2005, 03:40 AM
#1
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Which is better... 4.20x3.662 or 4.0x4.0 Was curious on what the thinking/performance benifit was on using big bore/small stroke vs something more traditional.
4.20 Bore x 3.662 Stroke for 401ci
or
4.0 Bore x 4.0 Stroke for 402ci
4.20 Bore x 3.662 Stroke for 401ci
or
4.0 Bore x 4.0 Stroke for 402ci
06-03-2005, 08:37 AM
#3
Make it square. Unless you already have a 4.20" bore block. I would think it would be cheaper to get a 4" bore block and a 4" crank.
Last edited by Muffracing; 06-03-2005 at 08:58 AM.
06-03-2005, 10:36 AM
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well, lets compare cost and performance gain.
you pay 3k for a MID sleeved block, THEN start adding on for forged internals, and all that fun stuff. or you can buy an LS2 block, that already has a 4.0 bore, and you can get that shortblock built for ~4k, or a little less if you assemble yourself. both will make comparable hp, but in slightly different places and the tq will be higher in the 402, due to the longer stroke.
personally i like close to sqaure, or a little heavy on the stroke. i think its the best of both worlds with the 402. but i like strokers, as long as its not crazy. torque is great
you pay 3k for a MID sleeved block, THEN start adding on for forged internals, and all that fun stuff. or you can buy an LS2 block, that already has a 4.0 bore, and you can get that shortblock built for ~4k, or a little less if you assemble yourself. both will make comparable hp, but in slightly different places and the tq will be higher in the 402, due to the longer stroke.
personally i like close to sqaure, or a little heavy on the stroke. i think its the best of both worlds with the 402. but i like strokers, as long as its not crazy. torque is great
06-03-2005, 11:09 AM
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assuming cost wasnt a factor is this senario...
Race application only...
I brought this up because i was talking to someone and they were saying something about piston speed and the rod angle and side loading the piston wall. That the Big Bore less stroke would be better.
Basically I wondering if everything being Identical, from a drag race setup, weather/suspension/etc etc... except for the motors.
would the car run faster with first setup or second?
Race application only...
I brought this up because i was talking to someone and they were saying something about piston speed and the rod angle and side loading the piston wall. That the Big Bore less stroke would be better.
Basically I wondering if everything being Identical, from a drag race setup, weather/suspension/etc etc... except for the motors.
would the car run faster with first setup or second?
06-03-2005, 03:14 PM
#7
If your going for a strip car, yes, the bigger bore would be better. It makes more power higher in the rpm range, which is where most strip cars live. As far as side loading, it's not really an issue till you get real heavy on the stroke. You shouldn't have any problems with a square set-up. It's when you start getting .125" + over sqare that you might run into some loading problems.
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06-03-2005, 03:40 PM
#8
If it were feasible, I'd take the all bore motor. A good head porter can use the extra space to improve flow and I don't mind shifting a built motor at 7,000 rpm.
The square motor may make a little more low end torque than an all bore, but remember the all bore has an extra 56 cubes over stock and it will use them to make more power everywhere. It will make plenty of low end power for street use. The extra low end power that a square motor might have would primarily be a benefit to an A4 with stock gears and a small converter, or possibly an M6 with stock gears. These combos rarely exist (most high performing A4 use 3500+ stalls and most M6's move up to 3.73s or higher gear).
The square motor may make a little more low end torque than an all bore, but remember the all bore has an extra 56 cubes over stock and it will use them to make more power everywhere. It will make plenty of low end power for street use. The extra low end power that a square motor might have would primarily be a benefit to an A4 with stock gears and a small converter, or possibly an M6 with stock gears. These combos rarely exist (most high performing A4 use 3500+ stalls and most M6's move up to 3.73s or higher gear).
