Screamer

What is the actual difference when it comes to the power curve??? If you have a 1.8L engine with 1.54 r/s ration and a 1.8L with 1.66 r/s ratio how would this effect the power curve???

Dancing is Forbidden

will it affect the power curve? I dont know. It will rev SAFER. thats for sure.

EKhatch

I think that it may have an effect on the torque given the fact that all other factors are identical but I really don't know for sure.

motoman

A higher rod ratio affects quite a few things. But, in general, an engine with a higher rod ratio CAN make more torque at a higher rpm (and hence, more hp), but will loose low rpm torque. However, if your induction system is not up to the task, then you will not gain that power. If you notice, engines that rev very high (and have a high hp output) will have very high rod ratios.

chrisCNL

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by motoman &raquo;</TD></TR><TR><TD CLASS="quote">A higher rod ratio affects quite a few things. But, in general, an engine with a higher rod ratio CAN make more torque at a higher rpm (and hence, more hp), but will loose low rpm torque. However, if your induction system is not up to the task, then you will not gain that power. If you notice, engines that rev very high (and have a high hp output) will have very high rod ratios.
</TD></TR></TABLE>

I agree with motoguy. ALso it will not put as much strain on your piston skirts and your rods due to the fact that the rod angle have been change.

Screamer

I am currently running a 2000 JDM ITR engine for road racing, but knowing me I will want to start modifying it very shortly. I already decided that I will do a race port and polish on the head with upgraded valvetrain and some aggressive cams (JUN 3s) since that is what you can consider "safe" power gains. What I would like to build on the side is another block(since modifying the bottom end is not considered as "safe") that I can just treat as a project and maybe learn something in the process. I was considering to build a b16a bottom end with b17 crank and sleeve/bored out to 85mm. This would result in ~1850cc displacement, but with a rod/strok ratio of 1.66, which is a little bit better than the stock b18c. Now for the question... is this gain in rod /stroke ratio worth while the project??? or would there be more benefit to build a b18c 2.1L engine with a worse rod/stoke ratio. My concern is that I drive this thing for 1-2hrs at a time on the track so I want something that is very reliable and makes nice smooth usable power. And now for the experet's opinions..........

Thanks!

alloutmotor

i would say the gain is worthwhile, especially since you spend up to hours racing and putting stress on the engine...

with an increased rod stroke ratio you will make more torque at higher rpms and also horsepower you will put less stress on the sleeves and piston skirts since the angle of the rod going up in the sleeves is decreased....so if your doing road racing you might want to build your engine for ultimate responce that way you can get into your powerband quickly

Screamer

That is exactly what I wanted to hear ... Thanks!!!

Now I am really excited about this build up.

Happy Holidays everyone

sgT

I think its more cost effective to stick with the b18c with 81mm bore and stock 1.8L crank.
The last road race motor i built was a stock ITR, made 190whp and lasted
2 seasons before a punctured radiator forced its retirement.

Upon disassembly it was like new inside.

If you want to sleeve for a 2L thats great, but to destroke just for a little bit
of rod stroke ratio isnt worth it.

Screamer

Can you please read the post befor you post your post... First of all I am not looking at displacement increase... second of all I am not destroking any enging i was askning about stroking a b16a with b17 carnk. READ BEFORE YOU REPLY!!!

GreenR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Screamer &raquo;</TD></TR><TR><TD CLASS="quote">Can you please read the post befor you post your post... First of all I am not looking at displacement increase... second of all I am not destroking any enging i was askning about stroking a b16a with b17 carnk. READ BEFORE YOU REPLY!!!</TD></TR></TABLE>

Dude Chill, SGT knows what he's talking about. Besides stroking a B16 with a B17 crank really isn't all that, you should try using a LS crank in your B16, for starters.

sgT

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Screamer &raquo;</TD></TR><TR><TD CLASS="quote">Can you please read the post befor you post your post... First of all I am not looking at displacement increase... second of all I am not destroking any enging i was askning about stroking a b16a with b17 carnk. READ BEFORE YOU REPLY!!!</TD></TR></TABLE>

Hey, spend your money however you want pal, i'm just offering advice.
B16A/B17As are a waste of money, plain and simple.

Suprdave

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sgT &raquo;</TD></TR><TR><TD CLASS="quote">B16A/B17As are a waste of money, plain and simple.
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This is what I tell people all the time...

And hey buddy (Screamer)...you got alot of ***** asking for advice then talking **** when someone gives it.

Drag R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Screamer &raquo;</TD></TR><TR><TD CLASS="quote">Can you please read the post befor you post your post... First of all I am not looking at displacement increase... second of all I am not destroking any enging i was askning about stroking a b16a with b17 carnk. READ BEFORE YOU REPLY!!!</TD></TR></TABLE>

LMAO, I don't think he know who he was talking to.

nick

Screamer

I don´t undersand some of the pleple here... who the f gives a f who I was talking too. When someone tells me something is no good just because I never listen to their opinion, that is also why i said what i said. If you are going to give an opinion, please state why. I am an engineer myslef and I can distinguish bull **** answers from once that make sense. So if someone has any good reason why a b17 or b16 would suck please state so, no of this carp about ... well you can make extra 10whp with a LS crank... try running that engine for 2hrs strate at the track racing and than we will talk.... please....

Hybrid96EK

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Screamer &raquo;</TD></TR><TR><TD CLASS="quote">I don´t undersand some of the pleple here... who the f gives a f who I was talking too. When someone tells me something is no good just because I never listen to their opinion, that is also why i said what i said. If you are going to give an opinion, please state why. I am an engineer myslef and I can distinguish bull **** answers from once that make sense. So if someone has any good reason why a b17 or b16 would suck please state so, no of this carp about ... well you can make extra 10whp with a LS crank... try running that engine for 2hrs strate at the track racing and than we will talk.... please.... </TD></TR></TABLE>

I don't think there is a single problem with either the B16 or the B17. I run a B17 in my hatch and have been more then happy with its output. I think people are just on the torque bandwagon. Its not hard at all to get the B17 to kick out similar numbers to a B18

TrboInteg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hybrid93Eg &raquo;</TD></TR><TR><TD CLASS="quote">
I think people are just on the torque bandwagon. </TD></TR></TABLE>

You act like torque is a bad thing? I happen to think torque is ok.

Hybrid96EK

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

You act like torque is a bad thing? I happen to think torque is ok.</TD></TR></TABLE>

I never said it was a bad thing. People just like to look at only torque. People need to consider gearing and vehicle weight as well, not just how much torque an engine makes.

Suprdave

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Screamer &raquo;</TD></TR><TR><TD CLASS="quote">I don´t undersand some of the pleple here... who the f gives a f who I was talking too. When someone tells me something is no good just because I never listen to their opinion, that is also why i said what i said. If you are going to give an opinion, please state why. I am an engineer myslef and I can distinguish bull **** answers from once that make sense. So if someone has any good reason why a b17 or b16 would suck please state so, no of this carp about ... well you can make extra 10whp with a LS crank... try running that engine for 2hrs strate at the track racing and than we will talk.... please.... </TD></TR></TABLE>

Wow Mr. Engineer, for someone who knows it all...you sure ask alot of questions.

GSR Block has a taller deck, period...B16s are junk when it comes to all-motor.

You can run a B18C5 until the cows come home, stock...what makes you think that a B16 is so much more reliable? You guys need to get off this rod\stroke garbage bandwagon...There are Rat Motors turning 9000 rpms...with like 600CI, and crazy Rod Angles. Get your heads out of your asses, please...

Hybrid96EK

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

Wow Mr. Engineer, for someone who knows it all...you sure ask alot of questions.

GSR Block has a taller deck, period...B16s are junk when it comes to all-motor.

You can run a B18C5 until the cows come home, stock...what makes you think that a B16 is so much more reliable? You guys need to get off this rod\stroke garbage bandwagon...There are Rat Motors turning 9000 rpms...with like 600CI, and crazy Rod Angles. Get your heads out of your asses, please...</TD></TR></TABLE>

So just because it has a taller deck its more desirable for all motor applications? Please explain. When discussing reliability, I don't think its fair to compare the B18C5 to a B16. Considering there are significant changes made to the B18C5 to bring it to the level its at and the B16 is well over 10 years old... This debate could go on and on. Rod/Stroke ratio DOES = less stress on the skirts and rods, no matter how you look at it. Does it make THAT much difference? I couldn't tell you. I don't have the resources to be able to run test after test. Its a debate that can go on and on. I don't think that a B16 is "junk" for all motor applications by any means though.

Suprdave

Higher Rod\Stroke ratio doesn't equal less stress...It equals less piston speed.

Hybrid96EK

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Suprdave &raquo;</TD></TR><TR><TD CLASS="quote">Higher Rod\Stroke ratio doesn't equal less stress...It equals less piston speed.

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How can I not reduce wear and stress if I reduce the speed at which something is traveling?

Suprdave

Run parts that arent as effected by the speed.

The difference in piston speeds betweena B18c5 and a B16a, don't outweigh the benefits of the better platform.

Suprdave

Hybrid96EK

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Suprdave &raquo;</TD></TR><TR><TD CLASS="quote">Run parts that arent as effected by the speed.

The difference in piston speeds betweena B18c5 and a B16a, don't outweigh the benefits of the better platform.

Suprdave</TD></TR></TABLE>

So then, it sounds like you are saying "yes, there are some advantages to a better rod/stroke ratio. However, in my opinion, these benefits are not enough to make the B16 a superior platform to the B18C5.". Is this correct? And what makes a taller deck so favorable for all motor applications?

Suprdave

A Taller Deck allows you to run a longer stroke, yet still keep the rods a decent length. Or, run a longer rod with the shorter stroke, like a B16B...but the thing is: Rod\Stroke Ratio is negligible unless we are talking extremes (95mm Crank in a Stock Deck B18C)...in that case, your head won't be capable of flowing well enough at those piston speeds, to supply the displacement. An All Out Race Head can, but we are assuming Road-Race\Street Engine. With a GSR Motor, you are running a head that is designed to flow well at the pistons speeds, therefore the 'gains' from running a shorter stroke will not outweigh the benefits of more displacement in any way...

You have to think of it like this: Honda came out with the B16a in 1989...then they realized it was a design that could be improved upon and released the B18C1 in 1994. A GSR\ITR Motor can rev as high and as safely as a B16a can. Either motor is going to have trouble making power above 8500-9000rpm without a all-out race setup.

Suprdave