388 vs 427, will there be a gain in peak rwhp?
#1
388 vs 427, will there be a gain in peak rwhp?
I think im on my last decision and I wanted to get some opinions before i decided against using a 4.0" stroker crank.
Im building a big nitrous based re-sleeved motor. with all the parts you see in my signature (240-250 @ .050 cam, absolute x2 heads)
A 388 all bore and a 427 should make almost identical real wheel horsepower correct?? But the 388 will make it at a little higher rpm and make alot less torque and less area under the curve correct???
With a 300-350 shot torque is almost to much trying to keep it down to get the car to hook and launch.... So a 388 with a ton of spray should ET just as well as a 427 without spending the big $$$$$ on a crankshaft correct??? I dont want to do with the 4.0" crank if rwhp will be close to the same.
Im building a big nitrous based re-sleeved motor. with all the parts you see in my signature (240-250 @ .050 cam, absolute x2 heads)
A 388 all bore and a 427 should make almost identical real wheel horsepower correct?? But the 388 will make it at a little higher rpm and make alot less torque and less area under the curve correct???
With a 300-350 shot torque is almost to much trying to keep it down to get the car to hook and launch.... So a 388 with a ton of spray should ET just as well as a 427 without spending the big $$$$$ on a crankshaft correct??? I dont want to do with the 4.0" crank if rwhp will be close to the same.
#2
TECH Fanatic
A 427 will always have the potential to make more power than the 388. The advantage of building a 427 with the same power as a 388 would be driveability and low end torque. It is all going to be centered around the size of the cam you are going to run...ie. you can run a bigger cam with the 427 to get more power or the same size cam to get similar power as the 388 but more power under the curve and better daily driver characteristics.
#5
Ive done a lot of dyno work and seen alot of "De-stroked" engines....
Common example would be a 406 SBC compared to a 377 (400 block with a 350 crank).
The 377 would dyno with a powerband thats shifter much higher in the rpm's (Loves to rev), the 406 would make alot more low/mid range but often actually peaks a little more rwhp. With less cubic inches.
Id say if you took a 388 and swapped to a 427 in identical form, you would probably actually make a few less rwhp PEAK (427 might peak @ 6000, 388 probably around 6500) but a TON more low and mid range torque.
the 427 would ET better by far in a 1/4 mile race but it wouldnt out MPH the 388 car (it might actually mph less), so a BIG nitrous motor might actually run faster with a 388 because you can use more nitrous off the line.... If a car is leaving on a 300 shot the 427 would serve no purpose, as the torque is usually unusable, since a 388/300n20 setup would make 800-900 rwtq off the line...
Anyone follow this theory or no?
Common example would be a 406 SBC compared to a 377 (400 block with a 350 crank).
The 377 would dyno with a powerband thats shifter much higher in the rpm's (Loves to rev), the 406 would make alot more low/mid range but often actually peaks a little more rwhp. With less cubic inches.
Id say if you took a 388 and swapped to a 427 in identical form, you would probably actually make a few less rwhp PEAK (427 might peak @ 6000, 388 probably around 6500) but a TON more low and mid range torque.
the 427 would ET better by far in a 1/4 mile race but it wouldnt out MPH the 388 car (it might actually mph less), so a BIG nitrous motor might actually run faster with a 388 because you can use more nitrous off the line.... If a car is leaving on a 300 shot the 427 would serve no purpose, as the torque is usually unusable, since a 388/300n20 setup would make 800-900 rwtq off the line...
Anyone follow this theory or no?
#6
That maybe true however why would you stick a cam that was designed for a 388 into a 427, the 427 will swallow a heck of a lot bigger cam. If you went all out in both motors the 427 would give you better results pending your car could handle all the power.
#7
TECH Fanatic
Originally Posted by 8cylinder6speeds
That maybe true however why would you stick a cam that was designed for a 388 into a 427, the 427 will swallow a heck of a lot bigger cam. If you went all out in both motors the 427 would give you better results pending your car could handle all the power.
I can say that if you are looking for a high reving motor (ie huge cam) you would probably be better off with the 388 setup. As you said above engines with long strokes do not like to be revved to the moon.
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#9
Originally Posted by timelord
Why not 427 with a 2 stage N2O set up for launch??
#10
TECH Senior Member
iTrader: (4)
Here's my take on this...MTI & ARE warranty their Big Bores with dry sleeves...but they don't warranty Big Bores with dry sleeves that get sprayed.
I don't think it's wise to spray a 300 shot on a dry sleeve Big Bore and expect it to live very long. The sleeves would be getting hit with a massive spikes in cylinder and with .08 to .06 of material holding a liner in place, I think that's asking for problems pretty quick. Likewise, almost all Big Bores use stock cranks and most use stock rods. Spraying off the line & down the 1/4...would probably subject the stock crank and rods to ~800+ flywheel hp and ~1000+ flywheel torque. I don't think a dry sleeved 427 would fair any better. Sounds like a time bomb to me and I like Big Bores.
With that said, I think a stroker is motor to go with to spray the **** out off. Not sure about the Eagle crank as we really don't know it's limits at this point for spraying 300shots but the Lunati rotating assembely in a stock bore LS1 should live quiet a while with good tune. I'd favor a LS1 block for big spray set ups because they don't have the windows that could weaken the structure like an LS6 block would have.
Just my rambling thoughts on this...
I don't think it's wise to spray a 300 shot on a dry sleeve Big Bore and expect it to live very long. The sleeves would be getting hit with a massive spikes in cylinder and with .08 to .06 of material holding a liner in place, I think that's asking for problems pretty quick. Likewise, almost all Big Bores use stock cranks and most use stock rods. Spraying off the line & down the 1/4...would probably subject the stock crank and rods to ~800+ flywheel hp and ~1000+ flywheel torque. I don't think a dry sleeved 427 would fair any better. Sounds like a time bomb to me and I like Big Bores.
With that said, I think a stroker is motor to go with to spray the **** out off. Not sure about the Eagle crank as we really don't know it's limits at this point for spraying 300shots but the Lunati rotating assembely in a stock bore LS1 should live quiet a while with good tune. I'd favor a LS1 block for big spray set ups because they don't have the windows that could weaken the structure like an LS6 block would have.
Just my rambling thoughts on this...
#11
TECH Fanatic
Originally Posted by 99 Black Bird T/A
Here's my take on this...MTI & ARE warranty their Big Bores with dry sleeves...but they don't warranty Big Bores with dry sleeves that get sprayed.
I don't think it's wise to spray a 300 shot on a dry sleeve Big Bore and expect it to live very long. The sleeves would be getting hit with a massive spikes in cylinder and with .08 to .06 of material holding a liner in place, I think that's asking for problems pretty quick. Likewise, almost all Big Bores use stock cranks and most use stock rods. Spraying off the line & down the 1/4...would probably subject the stock crank and rods to ~800+ flywheel hp and ~1000+ flywheel torque. I don't think a dry sleeved 427 would fair any better. Sounds like a time bomb to me and I like Big Bores.
With that said, I think a stroker is motor to go with to spray the **** out off. Not sure about the Eagle crank as we really don't know it's limits at this point for spraying 300shots but the Lunati rotating assembely in a stock bore LS1 should live quiet a while with good tune. I'd favor a LS1 block for big spray set ups because they don't have the windows that could weaken the structure like an LS6 block would have.
Just my rambling thoughts on this...
I don't think it's wise to spray a 300 shot on a dry sleeve Big Bore and expect it to live very long. The sleeves would be getting hit with a massive spikes in cylinder and with .08 to .06 of material holding a liner in place, I think that's asking for problems pretty quick. Likewise, almost all Big Bores use stock cranks and most use stock rods. Spraying off the line & down the 1/4...would probably subject the stock crank and rods to ~800+ flywheel hp and ~1000+ flywheel torque. I don't think a dry sleeved 427 would fair any better. Sounds like a time bomb to me and I like Big Bores.
With that said, I think a stroker is motor to go with to spray the **** out off. Not sure about the Eagle crank as we really don't know it's limits at this point for spraying 300shots but the Lunati rotating assembely in a stock bore LS1 should live quiet a while with good tune. I'd favor a LS1 block for big spray set ups because they don't have the windows that could weaken the structure like an LS6 block would have.
Just my rambling thoughts on this...
#12
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Originally Posted by 99 Black Bird T/A
Here's my take on this...MTI & ARE warranty their Big Bores with dry sleeves...but they don't warranty Big Bores with dry sleeves that get sprayed.
I don't think it's wise to spray a 300 shot on a dry sleeve Big Bore and expect it to live very long. The sleeves would be getting hit with a massive spikes in cylinder and with .08 to .06 of material holding a liner in place, I think that's asking for problems pretty quick. Likewise, almost all Big Bores use stock cranks and most use stock rods. Spraying off the line & down the 1/4...would probably subject the stock crank and rods to ~800+ flywheel hp and ~1000+ flywheel torque. I don't think a dry sleeved 427 would fair any better. Sounds like a time bomb to me and I like Big Bores.
With that said, I think a stroker is motor to go with to spray the **** out off. Not sure about the Eagle crank as we really don't know it's limits at this point for spraying 300shots but the Lunati rotating assembely in a stock bore LS1 should live quiet a while with good tune. I'd favor a LS1 block for big spray set ups because they don't have the windows that could weaken the structure like an LS6 block would have.
Just my rambling thoughts on this...
I don't think it's wise to spray a 300 shot on a dry sleeve Big Bore and expect it to live very long. The sleeves would be getting hit with a massive spikes in cylinder and with .08 to .06 of material holding a liner in place, I think that's asking for problems pretty quick. Likewise, almost all Big Bores use stock cranks and most use stock rods. Spraying off the line & down the 1/4...would probably subject the stock crank and rods to ~800+ flywheel hp and ~1000+ flywheel torque. I don't think a dry sleeved 427 would fair any better. Sounds like a time bomb to me and I like Big Bores.
With that said, I think a stroker is motor to go with to spray the **** out off. Not sure about the Eagle crank as we really don't know it's limits at this point for spraying 300shots but the Lunati rotating assembely in a stock bore LS1 should live quiet a while with good tune. I'd favor a LS1 block for big spray set ups because they don't have the windows that could weaken the structure like an LS6 block would have.
Just my rambling thoughts on this...