Okay if use a b16 crank in a b16 block but use b18 con rods will that give me the shortest stroke?

 

No, use B16 rods for the shortest stroke. Do you mean longer stroke?

 

I want the pistons to move the least amount possible, if I were to use a longer rod then the piston would travel less. If i were to use a short rod the a bigger crank then i would have a longer stroke.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">I want the pistons to move the least amount possible, if I were to use a longer rod then the piston would travel less.</TD></TR></TABLE>
Wouldn't it still move the same distance regardless of the rod length because you're still using the same crank? Or am I missing something here?

 

stroke will not change unless u change the crank. What u are talking about is a better rod/stroke ratio. what you want is a long rod and short stroke. B16a stock is 1.74 the b16b is even higher at 1.84. using a longer rod will just move the piston up farther, not affecting stroke at all. what i think you want to do is to have the least amount of lateral momentum. which would be achieved by using a b16b crank and a custom length rod with custom pistons.

 

So using a b16b crank with say itr rods wont shorten the stroke at all? if i use longer rods then the piston seat time will be longer, making the stroke shorter. same basic principal of wheel hub, the outside is moving faster than the hub. the longer rod makes the piston move less to go all the way around the crank stroke.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">So using a b16b crank with say itr rods wont shorten the stroke at all? if i use longer rods then the piston seat time will be longer, making the stroke shorter. same basic principal of wheel hub, the outside is moving faster than the hub. the longer rod makes the piston move less to go all the way around the crank stroke.</TD></TR></TABLE>
Are you on crack?

The distance between BDC and TDC will be the same if you have a 2 inch rod or a 2 foot rod. You can't change the stroke unless you change the crank.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">So using a b16b crank with say itr rods wont shorten the stroke at all? if i use longer rods then the piston seat time will be longer, making the stroke shorter.</TD></TR></TABLE>

360 degrees is still a complete revolution. Just cause you change the rods doesnt mean its going to change the stroke. The crank determines how much the piston goes up and down. Changing the rod length will effect the rod stroke ratio along with the piston acceleration and speed but not stroke.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">same basic principal of wheel hub, the outside is moving faster than the hub. the longer rod makes the piston move less to go all the way around the crank stroke.</TD></TR></TABLE>

The outside of the wheel is still making the same 360 degree revolution as the center of the hub, its just the outside of the wheel has more ground to cover so it has to spin faster then the center of the hub that has less area to cover to make the 360.

Hope this clears some things up.

 

yeah by changeing the rod length all your affecting is the R/S ratio, and the fact your now smashing your pistons into your valves and trying to push your head off your block. By all means with 99 posts and still no common sense to realize how flawed your plan is, you should just take your ideas to a builder and have them tell you what you need to do. And dont try to "experiment" yourself, for the engines sake.

 

Another thing to consider-the shorter the stroke, the higher you are going to have to rev the motor to get your power.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">So using a b16b crank with say itr rods wont shorten the stroke at all? if i use longer rods then the piston seat time will be longer, making the stroke shorter. same basic principal of wheel hub, the outside is moving faster than the hub. the longer rod makes the piston move less to go all the way around the crank stroke.</TD></TR></TABLE>

i'm not sure if this has been adequately explained yet....

the spoke of the wheel rotates in a 360 degree circle around the hub, while a connecting rod makes two 180 degree passes every time the crank turns, it doesnt go below....think about the way the crank moves the rod up and down.....

 

What are you trying to achieve? i can answer you questions if i know.

if stroke is all you're worried about then use any b16 crank. if its rod ratio, we could be discussing it for months because it changes piston max speed, rod angularity, dwell times at both top and bottom dead center, and so on...

 

maybe he wants a REALLY high rev motor.

 

Stroke is how far a piston moves up and down in its bore.

Rod length does not affect stroke at all.

You could run 10 inch long connecting rods, on a B16 crank and you could run 10 feet long connecting rods, on a B16 crank the stroke hasn't changed.

 

My plan was to build my own high reving engine. Im looking for ctr rev range and no danger.

 

CTR rev range meaning what? if you want a high reving motor then just get a b16b, aftermarket rods, pistons etc. and then rev it to high heaven if you want u want a high revving motor its not stroke you should be worried about, its rod/stroke ratio, the higher the better in your case. so 1.83 r/s of the b16B is hard to beat

 

well i just didnt want to be another guy with a swapped motor that was still all stock. thats why i wanted to build my own motor, i know to many people that drive around with swapped cars but havent done anything to them, so if i did the ctr i would want to change things, so then im back to the point to where i would rather just build my b16 and save some money.

my last questions are: are the b18 and b16 blocks the same except for the deck height, is the bore the same? can i use b16 internals in a b18 block? well i know i would hvae to use b18 con rods but is the rest the same?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">my last questions are: are the b18 and b16 blocks the same except for the deck height, is the bore the same? can i use b16 internals in a b18 block? well i know i would hvae to use b18 con rods but is the rest the same?</TD></TR></TABLE>

As far as blocks, B16B (CTR) and B18C (ITR/GSR) blocks are exactly the same. B16A blocks are shorter. All the B16/17/18a/18b/18c engines are 81mm bore. You could run a B16B crank, rods and pistons in a B18 block.

If you put a B16A crank in a B18 block, I don't know what rods you'd use but they'd be B16B length. The problem, if it was explained to me correctly, is B16A cranks use wide rods on the big end, and B16B cranks use narrow rods like an ITR.

Based on my experiences, bigger engines are better. You can make big HP numbers twisting the pee out of little engines or you can make the same power with less RPM (stress) and have more power under the curve, which means it'll be quicker and easier to drive daily.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">my last questions are: are the b18 and b16 blocks the same except for the deck height, is the bore the same? can i use b16 internals in a b18 block? well i know i would hvae to use b18 con rods but is the rest the same?</TD></TR></TABLE>
There is a RED link at the top, right-hand corner of your screen. Use it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B20C5 Turbo &raquo;</TD></TR><TR><TD CLASS="quote">
There is a RED link at the top, right-hand corner of your screen. Use it.</TD></TR></TABLE>

So youre telling me that I could have compared b16 blocks and found out about the ctr crankshaft. essentially destroking a motor? Nobody does this so no one has any input, only a few guys in here have probably done this, I dont want to go big, maybe i should get a type r head on a b20 and then turbo it so i never have to rev it real high. if thats the case then why did honda spend all that time making a whole motor thats different for the civic type r. i wanted high revs not a bunch of tourqe. if i wanted tourqe i would go and get a chevelle or something, i dont think that hondas are known for much tourqe in the first place. sorry i got kinda angry, but i already did a search and all i got was big bore drag motor building and crap like that. this car i putting together is for road racing only, no street racing no driving on regular basis. I am going to drive it everyday, but i would rather sacrifice ease of driving to be able to say i rev to 10k and i make more power than you do. (not u personally) but the guys around here cruising around here with stock swaps and crap like that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kevinarich &raquo;</TD></TR><TR><TD CLASS="quote">

So youre telling me that I could have compared b16 blocks and found out about the ctr crankshaft. essentially destroking a motor? Nobody does this so no one has any input, only a few guys in here have probably done this, I dont want to go big, maybe i should get a type r head on a b20 and then turbo it so i never have to rev it real high. if thats the case then why did honda spend all that time making a whole motor thats different for the civic type r. i wanted high revs not a bunch of tourqe. if i wanted tourqe i would go and get a chevelle or something, i dont think that hondas are known for much tourqe in the first place. sorry i got kinda angry, but i already did a search and all i got was big bore drag motor building and crap like that. this car i putting together is for road racing only, no street racing no driving on regular basis. I am going to drive it everyday, but i would rather sacrifice ease of driving to be able to say i rev to 10k and i make more power than you do. (not u personally) but the guys around here cruising around here with stock swaps and crap like that.</TD></TR></TABLE>
no offence but do you enjoy going throught 6K of worthless powerband?
Why not get a sport bike?

There is a reason no one runs a 1.2L b16 that goes to 14K. Reasons already have being listed, I see no need to beat them over your head again.

You want torque trust me.

Torque is why I drive my LS1 every day instead of my lsvtec.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ***-assin &raquo;</TD></TR><TR><TD CLASS="quote">You want torque trust me.

Torque is why I drive my LS1 every day instead of my lsvtec.</TD></TR></TABLE>
The following is my opinion as a student of Calculus and physics:
No, horsepower in low rpms is why you drive it. The torque curve is only important because it determines the horsepower curve because horsepower is torque over time....literally. Maybe I'm misunderstanding the relationship between force, velocity, torque, and subsequent acceleration but as far as I see it, torque is the measure of how much force is being applied to your crank (with a certain radius) minus heat loss due to gears, clutch, etcetera and horsepower is how much torque you have versus time aka force times velocity...so, you have a certain force from the amount of torque but velocity is angular velocity or rotations per minute.

So basically, it's not only how much work you can do but also how fast you can do it. Think about it. Sure bikes are a quarter of our weight and at most half our displacement but those tiny engines don't have the proportional amount of torque that you'd expect, it's revving to 14k-16k that makes them so damn fast.

Another point is that (although many people would argue with me) some Formula 1 teams (next year when the new rules go into effect) may opt for the lower displacement (and therefore torque) of a v8 but have unlimited rpms vs. their other option, have a v10 that only goes to 20k (hahaha, only 20k ^_^). All I'm trying to say is that, you are calling Ferrari, Mclaren, Mercedes, Toyota, Renault, BMW, and Honda liars, and that's just bad/wrong.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Formula1 &raquo;</TD></TR><TR><TD CLASS="quote">
The following is my opinion as a student of Calculus and physics:
No, horsepower in low rpms is why you drive it. The torque curve is only important because it determines the horsepower curve because horsepower is torque over time....literally. Maybe I'm misunderstanding the relationship between force, velocity, torque, and subsequent acceleration but as far as I see it, torque is the measure of how much force is being applied to your crank (with a certain radius) minus heat loss due to gears, clutch, etcetera and horsepower is how much torque you have versus time aka force times velocity...so, you have a certain force from the amount of torque but velocity is angular velocity or rotations per minute.

So basically, it's not only how much work you can do but also how fast you can do it. Think about it. Sure bikes are a quarter of our weight and at most half our displacement but those tiny engines don't have the proportional amount of torque that you'd expect, it's revving to 14k-16k that makes them so damn fast.

Another point is that (although many people would argue with me) some Formula 1 teams (next year when the new rules go into effect) may opt for the lower displacement (and therefore torque) of a v8 but have unlimited rpms vs. their other option, have a v10 that only goes to 20k (hahaha, only 20k ^_^). All I'm trying to say is that, you are calling Ferrari, Mclaren, Mercedes, Toyota, Renault, BMW, and Honda liars, and that's just bad/wrong.</TD></TR></TABLE>
You may very well be right, its been years since I had those classes.

This is a nice part of this board the politness and debates. It is pretty late and i've been crunching numbers for taxes all day so my brain is off anway.

I sorta get what you mean but i'm a little lost, you might be astray in your veiws as you listed or I might be in over my head.

Would a stock LS1 dnyo graph help you explain what you mean? I would like to learn

 

I'm sure you've heard of the formula hp = (tq*rpm)/5252 well if you look at ANY dyno graph horsepower and torque will be equal at 5252 rpms which validates this formula (when rpms are equal to 5252 they cancel out and hp = tq). After 5252 horsepower will always be greater because the ratio of rpm to 5252 is greater than 1 so hp is some percentage (greater than 100%) of tq. This is of course why honda engines (and any engine revving past 5k) have a lot more hp than tq. Because even in turbo cars where you get crazy tq numbers, hp will always be greater by a percentage equal to (rpm/5252) * 100.

It might interest you to know that I am a junior in high school but I'm planning on building a 12.5k rpm motor that will break the 300whp mark and it'll only be 1.8 liters. I've done a fair amount of calculations and now I've done almost 5 pages of calculus trying to find exact quarter mile times based on my predicted tq curve and laws of angular velocity, angular acceleration and torque. It's actually quite complicated when you get into details. If anyone thinks they might be able to help me with this I would appreciate a pm or an email (prophetofthenight@gmail.com &lt;&lt;&lt; me) so that I can tell you what I've already done and the angle I'm trying to attack the problem from. Being that I've never had a formal physics c course and have only read several books on the subject, I think I'm getting very lost and confused...no, actually I know I'm very lost and confused ^_^.

I also appreciate your friendly manner in dealing with a subject that would easily create a flame battle amongst some of my "peers". I hope more people will chime in and shed some light on all of our questions

P.S. an ls1 dyno might help me explain my point though any dyno would help really (an ls1 vs. lsvtec dyno would be the best since that's the example you gave)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Formula1 &raquo;</TD></TR><TR><TD CLASS="quote">I'm sure you've heard of the formula hp = (tq*rpm)/5252 well if you look at ANY dyno graph horsepower and torque will be equal at 5252 rpms which validates this formula (when rpms are equal to 5252 they cancel out and hp = tq). After 5252 horsepower will always be greater because the ratio of rpm to 5252 is greater than 1 so hp is some percentage (greater than 100%) of tq. This is of course why honda engines (and any engine revving past 5k) have a lot more hp than tq. Because even in turbo cars where you get crazy tq numbers, hp will always be greater by a percentage equal to (rpm/5252) * 100.

It might interest you to know that I am a junior in high school but I'm planning on building a 12.5k rpm motor that will break the 300whp mark and it'll only be 1.8 liters. I've done a fair amount of calculations and now I've done almost 5 pages of calculus trying to find exact quarter mile times based on my predicted tq curve and laws of angular velocity, angular acceleration and torque. It's actually quite complicated when you get into details. If anyone thinks they might be able to help me with this I would appreciate a pm or an email (prophetofthenight@gmail.com &lt;&lt;&lt; me) so that I can tell you what I've already done and the angle I'm trying to attack the problem from. Being that I've never had a formal physics c course and have only read several books on the subject, I think I'm getting very lost and confused...no, actually I know I'm very lost and confused ^_^.

I also appreciate your friendly manner in dealing with a subject that would easily create a flame battle amongst some of my "peers". I hope more people will chime in and shed some light on all of our questions

P.S. an ls1 dyno might help me explain my point though any dyno would help really (an ls1 vs. lsvtec dyno would be the best since that's the example you gave)</TD></TR></TABLE>what size turbo are you planning on using?