Cranks & Displacement, how do they effect spool up time? (motor builders needed)
05-10-2006, 10:50 AM
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Cranks & Displacement, how do they effect spool up time? (motor builders needed)
Trying to design my next build, I have a numerous amount of different setups i'm thinking about running. The main question i'm having is which cranks in which blocks will have the largest effect on displacement, or is the effect null?
(all these will be run with mildly stock b16head 83mm pistons)
Compression aside, which setup will theorectically yield best tq, and why?
A: b18c block w/ LS crank +rods 83mm pistons
B. b18b block w/ ls crank + rods 83mm pistons
C. b16b block w/ ls crank + rods 83mm (pretty much same as b18c, just bling factor)
D. b18c block, GSR crank + rods, 83mm
I guess my question is using an LS crank, is there any downside, upside?
(all these will be run with mildly stock b16head 83mm pistons)
Compression aside, which setup will theorectically yield best tq, and why?
A: b18c block w/ LS crank +rods 83mm pistons
B. b18b block w/ ls crank + rods 83mm pistons
C. b16b block w/ ls crank + rods 83mm (pretty much same as b18c, just bling factor)
D. b18c block, GSR crank + rods, 83mm
I guess my question is using an LS crank, is there any downside, upside?
05-10-2006, 10:56 AM
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Re: Cranks & Displacement, how do they effect spool up time? (integranator)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integranator »</TD></TR><TR><TD CLASS="quote">
C. b16b block w/ ls crank + rods 83mm (pretty much same as b18c, just bling ?</TD></TR></TABLE>
sorry to break it to u boss.. but u cant use the LS crank in any B16 block unless u have a deck installed.. deck height on B16 are too short to use a ls crank ..
C. b16b block w/ ls crank + rods 83mm (pretty much same as b18c, just bling ?</TD></TR></TABLE>
sorry to break it to u boss.. but u cant use the LS crank in any B16 block unless u have a deck installed.. deck height on B16 are too short to use a ls crank ..
05-10-2006, 11:13 AM
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Re: Cranks & Displacement, how do they effect spool up time? (ValleySyder)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ValleySyder »</TD></TR><TR><TD CLASS="quote">sorry to break it to u boss.. but u cant use the LS crank in any B16 block unless u have a deck installed.. deck height on B16 are too short to use a ls crank ..</TD></TR></TABLE>
Try again bud. b16b= b18c block (has oil squirters I'm pretty sure), b16a crank, & longer rods.
Also to answer your question. Displacement owns. In your scenario, the all bores are the same, and with the exception of oil squirters, the blocks are almost the same, so it comes down to stroke, which the ls has plenty of (89 vs 87.50 vs 77.40), so you have the edge of around 25cc.
Try again bud. b16b= b18c block (has oil squirters I'm pretty sure), b16a crank, & longer rods.
Also to answer your question. Displacement owns. In your scenario, the all bores are the same, and with the exception of oil squirters, the blocks are almost the same, so it comes down to stroke, which the ls has plenty of (89 vs 87.50 vs 77.40), so you have the edge of around 25cc.
05-10-2006, 11:13 AM
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Re: Cranks & Displacement, how do they effect spool up time? (ValleySyder)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ValleySyder »</TD></TR><TR><TD CLASS="quote">
sorry to break it to u boss.. but u cant use the LS crank in any B16 block unless u have a deck installed.. deck height on B16 are too short to use a ls crank ..</TD></TR></TABLE>
but yes pumpkin, i said b16<U>B</U>
edit: he beat me to it, but I still like my response. Anyone else?
sorry to break it to u boss.. but u cant use the LS crank in any B16 block unless u have a deck installed.. deck height on B16 are too short to use a ls crank ..</TD></TR></TABLE>
but yes pumpkin, i said b16<U>B</U>
edit: he beat me to it, but I still like my response. Anyone else?
05-10-2006, 11:21 AM
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Yes the B16B block is same deck height as B18B, B20B/Z and B18C motors, it has a 77.4mm stroke with long rods.
To the original poster, the difference of teh B16B, B18A/B or B18C blocks with the LS crank won't make a damn difference except the LS block with need an LS/VTEC kit conversion where as the VTEC blocks won't and you lose your oil quirters WHICH are not needed with aftermarket forged pistons anyways. I have a GSR block with LS crank , it was 83mm BUT now being punched out to 84mm
Edit:The GSR cranks have 87.2mm stroke to correct Unsivil_audio
above
To the original poster, the difference of teh B16B, B18A/B or B18C blocks with the LS crank won't make a damn difference except the LS block with need an LS/VTEC kit conversion where as the VTEC blocks won't and you lose your oil quirters WHICH are not needed with aftermarket forged pistons anyways. I have a GSR block with LS crank , it was 83mm BUT now being punched out to 84mm
Edit:The GSR cranks have 87.2mm stroke to correct Unsivil_audio
above
05-10-2006, 11:25 AM
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Oh one other thing to consider. You can have a huge stroke and a really crappy r/s, it'll only give you a really low (rpm) peak torque. Hence why you see b16's making peak torque and 6k+ (because of their shorter stroke) whereas Ls/GSR's are ~5k. Camshaft selection has a pretty big effect on this also. So its best to keep your r/s within reason.
05-10-2006, 11:29 AM
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Re: (Unsivil_audio)
Appreciate the help so quickly guys . So, my ideal setup at this point in time, i'm going to go with this:
b16b block + ls crank + LS rods + 83mm cp 9:1's on a b16head, yielding me a... possible 9.7ish:1 compression? Have a set of 01 itr cams as well in the head.
Now, another question, what would the compression difference's be using the gsr crank/rods setup be like, and why is it different?
. So, my ideal setup at this point in time, i'm going to go with this:b16b block + ls crank + LS rods + 83mm cp 9:1's on a b16head, yielding me a... possible 9.7ish:1 compression? Have a set of 01 itr cams as well in the head.
Now, another question, what would the compression difference's be using the gsr crank/rods setup be like, and why is it different?
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05-10-2006, 11:47 AM
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Re: (Unsivil_audio)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Unsivil_audio »</TD></TR><TR><TD CLASS="quote">Oh one other thing to consider. You can have a huge stroke and a really crappy r/s, it'll only give you a really low (rpm) peak torque. Hence why you see b16's making peak torque and 6k+ (because of their shorter stroke) whereas Ls/GSR's are ~5k. Camshaft selection has a pretty big effect on this also. So its best to keep your r/s within reason. </TD></TR></TABLE>
See sig for discussion on rod/stroke ratio bullshit. There's nothing wrong about peaking torque earlier, it makes for a fatter powerband. That's typically what you want out of a street motor, last time I checked.
</TD></TR></TABLE>See sig for discussion on rod/stroke ratio bullshit. There's nothing wrong about peaking torque earlier, it makes for a fatter powerband. That's typically what you want out of a street motor, last time I checked.
05-10-2006, 12:21 PM
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^-yes I remember when earl said that.
Those arent really hard/set-in-stone numbers, but I am quite convinced based on the dyno charts I've seen, r/s has alot to do how quickly your power falls off after peak torque.
Those arent really hard/set-in-stone numbers, but I am quite convinced based on the dyno charts I've seen, r/s has alot to do how quickly your power falls off after peak torque.
05-10-2006, 01:18 PM
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Re: (Unsivil_audio)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Unsivil_audio »</TD></TR><TR><TD CLASS="quote">^-yes I remember when earl said that.
Those arent really hard/set-in-stone numbers, but I am quite convinced based on the dyno charts I've seen, r/s has alot to do how quickly your power falls off after peak torque.</TD></TR></TABLE>
Rod/Stroke ratio has PEANUTS to do with how your torque falls off. Camshafts, cylinder head flow, turbo selection, intake manifold design, and even exhaust manifold design have an infinitely greater effect on how torque falls off than a rod/stroke ratio.
The reason torque falls off quicker in an LS/GSR cranked motor is due to the longer stroke, not because of some fabled rod/stroke ratio crap.
Those arent really hard/set-in-stone numbers, but I am quite convinced based on the dyno charts I've seen, r/s has alot to do how quickly your power falls off after peak torque.</TD></TR></TABLE>
Rod/Stroke ratio has PEANUTS to do with how your torque falls off. Camshafts, cylinder head flow, turbo selection, intake manifold design, and even exhaust manifold design have an infinitely greater effect on how torque falls off than a rod/stroke ratio.
The reason torque falls off quicker in an LS/GSR cranked motor is due to the longer stroke, not because of some fabled rod/stroke ratio crap.
05-10-2006, 03:08 PM
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Re: (integranator)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integranator »</TD></TR><TR><TD CLASS="quote">so, can anyone help me with the piston compression dilema?</TD></TR></TABLE>
A 9:1 CP piston designed for an 83mm LS/VTEC will likely put you right around 9:1 compression with your setup. CP doesn't release their dish/dome volumes usually, but you can check out other companies like JE, Arias, or Wiseco and pick a dish size that reflects your desired compression ratio.
A 9:1 CP piston designed for an 83mm LS/VTEC will likely put you right around 9:1 compression with your setup. CP doesn't release their dish/dome volumes usually, but you can check out other companies like JE, Arias, or Wiseco and pick a dish size that reflects your desired compression ratio.
05-10-2006, 03:09 PM
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Re: (integranator)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integranator »</TD></TR><TR><TD CLASS="quote">so, can anyone help me with the piston compression dilema?</TD></TR></TABLE>
What is your dilema?
The difference between a GSR crank and LS crank is approx .2 CR
What is your dilema?
The difference between a GSR crank and LS crank is approx .2 CR
05-10-2006, 06:32 PM
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Re: Cranks & Displacement, how do they effect spool up time? (integranator)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by integranator »</TD></TR><TR><TD CLASS="quote">
but yes pumpkin, i said b16<U>B</U>
edit: he beat me to it, but I still like my response. Anyone else?</TD></TR></TABLE>
READING OWNS me !!my fault i didnt catch the B at the end of B16.. i assume with out lookin u was talkin bout our regular b16A motor instead of the hard find , every once and a while B16B gem ...
why 83mm bore instead of your average 84mm on most FI set up seen here ?
but yes pumpkin, i said b16<U>B</U>
edit: he beat me to it, but I still like my response. Anyone else?</TD></TR></TABLE>
READING OWNS me !!my fault i didnt catch the B at the end of B16.. i assume with out lookin u was talkin bout our regular b16A motor instead of the hard find , every once and a while B16B gem ...
why 83mm bore instead of your average 84mm on most FI set up seen here ?
05-11-2006, 06:51 AM
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Re: Cranks & Displacement, how do they effect spool up time? (ValleySyder)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ValleySyder »</TD></TR><TR><TD CLASS="quote">
READING OWNS me !!my fault i didnt catch the B at the end of B16.. i assume with out lookin u was talkin bout our regular b16A motor instead of the hard find , every once and a while B16B gem ...
why 83mm bore instead of your average 84mm on most FI set up seen here ? </TD></TR></TABLE>
caught a sweet deal on the 83's, couldn't pass it up.
READING OWNS me !!my fault i didnt catch the B at the end of B16.. i assume with out lookin u was talkin bout our regular b16A motor instead of the hard find , every once and a while B16B gem ...
why 83mm bore instead of your average 84mm on most FI set up seen here ?
</TD></TR></TABLE>caught a sweet deal on the 83's, couldn't pass it up.
05-11-2006, 08:14 AM
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Re: Cranks & Displacement, how do they effect spool up time? (integranator)
Sounds like you are doing things backwards. The size of the exhaust wheel is what really controls spool time. You pick your engine combo you want to run and then design the turbo wheel for that engine.
05-11-2006, 08:21 AM
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heres a tip on how i built my tq monster
2.1 gsr block
ls crank
b16 head w/ gsr cams
je 9:1 pistons 84.5mm bore
sc61
I made 335 hp and 300 lb tq @12 psi
and i was very satisfied.
2.1 gsr block
ls crank
b16 head w/ gsr cams
je 9:1 pistons 84.5mm bore
sc61
I made 335 hp and 300 lb tq @12 psi
and i was very satisfied.
05-12-2006, 02:56 AM
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Re: (fabe85)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fabe85 »</TD></TR><TR><TD CLASS="quote">heres a tip on how i built my tq monster
2.1 gsr block
ls crank
b16 head w/ gsr cams
je 9:1 pistons 84.5mm bore
sc61
I made 335 hp and 300 lb tq @12 psi
and i was very satisfied.</TD></TR></TABLE>
That's great and all, but an 84.5mm LS cranked motor displaces 1997CC's, definitely not 2.1 litres, and there is something else about your setup responsible for the 300 ft-lbs of torque, likely a boost spike or an incorrect dyno reading.
2.1 gsr block
ls crank
b16 head w/ gsr cams
je 9:1 pistons 84.5mm bore
sc61
I made 335 hp and 300 lb tq @12 psi
and i was very satisfied.</TD></TR></TABLE>
That's great and all, but an 84.5mm LS cranked motor displaces 1997CC's, definitely not 2.1 litres, and there is something else about your setup responsible for the 300 ft-lbs of torque, likely a boost spike or an incorrect dyno reading.
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