Bontke

I have always been a stoker fan. So I'll ask a question, doesn't stroking make more power than boring out the cylinder? In this example I am talking about the B18 series engines. I haven't been able to find good dynos of people with actually stroked (not over bored) B18's mostly overbored B18's.

When it comes down to it the stroker has to make more torque, right? Look at a bicycle crank for example. If the bike crankshaft is short from the pedal to the center it makes the bike easier to pedal, but if the peadel to center is longer it requires more torque.

Another example is trying to remove lug nuts with a 12" breaker bar and using a 36" breaker bar. Less effort is used on the larger bar to remove the nuts. So in an engine increasing the crank stroke would make more torque than increasing the piston diameter. Using the same ammount of force (piston size) on a longer crank stroke....right? Adding oversized pistons would help add to the effect.

Anyone? I need enlightment.

PSU-TEG

Well, yes... (without actually running the numbers) ... I believe you are probably correct in thinking that larger stroke would create more torque at any given RPM than boring the cylinders would. Just remember, you can increase torque (Torque = Force x Distance) by increasing the force (Boring) instead of the distance (Stroking). However, when you "stroke" the engine. You obviously increase the stroke, while keeping the rod lenth the same. This lowers your R/S Ratio (Rod Lenth to Stroke Ratio). And to sum up R/S Ratio real quick, this is bad because a low R/S Ratio causes the max Rod angle to become more horizontal, and results in a lot more pressure on the cylinder wall. As a result of this, you can not rev the engine as high. With a serious Stroker Kit, 2.1L, you revs should be limited to about 6,000 RPMs, which limits you from getting to the high RPMs where Hondas thrive. (If you are not fimilar with the Low R/S Ratio problem, do a search of this forum and others for more info)

Due to this, the increase in power and performance that you would get from more torque at about 5,000 - 6,000 RPMs from the Stroker Kit, would not be greater than the increase in power and performance that you would see at about 8,000 - 9,000 RPMs from boring out a Honda engine to get more force.

But... keep asking around, I don't claim to be an expert by any means. However, this is my understanding and opinion on the matter.

Good Luck!


[Modified by PSU-TEG, 6:11 AM 10/8/2002]


[Modified by PSU-TEG, 7:39 AM 10/8/2002]


[Modified by PSU-TEG, 7:41 AM 10/8/2002]

Bontke

I have a hard time believeing that an aftermarket stroker kit would be designed around poor rod ratio. Think about it.... Here I am selling a product that will increase displacement, but reduce engine redline. I would think that crower would have designed a stroker kit that moved the wrist pin inside the pistion to work with the longer stroke thus increasing redline and displacement. Stroker kits for every other engine increase displacement and redline, why would the honda b series engine be the only one to suffer torque for redline? Well I need to call crower and talk to aomeone who know their stuff.

Do all Honda B series engines suffer from R/S ratio?!?

Suprdave

A Proper Stroker Kit, would raise the pistoon\ring package and keep the R\S Ratio close to the same.

Suprdave

JCushing

compare the r/s ratio and the bore / stroke difference of different hondas... that will give you an idea of what they do ie d16 vs b16.... b16 vs b18c and so on

basically a stroker gives you more tq but makes you gasp at higher rpms... full race all motors are alot of times stroked and bored to the max cause theres no reliability factor...

Quick 200k Mile Motor

Rod > stroke (long rod + short crank) will lower the squish velocity. A short rod + longer stroke crank will raise that velocity. So its better to stay below 1.75:1 for rod/stroke if your taste is NA.

NA 1.54:1
Boost 1.75:1

If you have rod < stroke (short rod + longer stroke), basically a NA built up and you decide to boost, you can produce some highend output (almost like a high rod ratio motor) by having the head & combustion chamber reworked ..for more volume, squish thickness or squish area.

Bontke

Is their a website that lists the different RS ratios among honda engines?

I am looking to build and engine that will provide over 125 lb of torque at or below 3000 PRM. Then use a turbo for top end. I want to run a larger size turbo for some top end, but have enough torque on the low end to over come some of the turbo lag.

JCushing

when you stroke a motor to make low end power like the the velocity of the piston at higher rps gets real fast real quick.. this is a reason they tend to die out at high rpms, the pistons is simply going to fast to get alot of top end power... this is why a b16 with long duration cams makes nasty top end... if you wanna boost your better off with a better r/s ration because of geometry and also sideloading of a stroker motor.. a turbo will more than make the low end tq you want, just size it right.. also theres no point in making power below 3000 because just about any tranny you put on will put you over 3000 when you shift gears

JCushing

basically uou want your tq curve to be in the power band if the transmision your using

advanracing62

So then tell me why JUN has a stroker kit that will work with the stage III package and STILL rev to 9500?!! Over 275 whp from this kit in a B16 and this has been in a car that runs Solo I and is a daily. I'm just curious how that would be possible according to some of the information here.... not flaming, just trying to get some knowledge as I'm in the process of building my block again.

Bontke

I want that torque down low for daily driving. How often are you goin to normally shift the car at 5K? Plus more torque down low pulls cars off the line...no need to wait for the v-tec....that's what wins races.

Finally some one who sees that strokers can be built to rev. All this carp of R/S ratio this and that is a load of bull (I'm talking about having a low R/S ratio with a stroker). You get the right specs and then you have a perfectly reliable stroked high RPM engine. No one takes the time to really research this, actually call a engine building wizzard and have him crunch some numbers. There are thousads of other cars out there with strokers that rev high....why would honda be the only one limited to a low revving stroker? It has the largest aftermarket parts following, some body has to do it right.

advanracing62

upon doing some research and what not I have learned this. If you use a stroker kit from Crower or JG you will lose your oil squirters and have a very poor RSR. JUN is the only company that I have talked to that stated thier stroker kits are basically just like a stock setup. You retain the squirters and have a decent RSR. Now, mind you, I don't think that the RSR of a stroked motor is all that great, but you can rev the JUN safely to 95k. If you have any doubts you can direct them to JUN USA ask for Fabio. He has a B16 stroked and it puts down some good power, and he revs high, and drives it all the time.

MikeSarr_GSR

stroking a B16 is not quite as difficult considering its taller deck height and almost ideal RSR to begin with. what kind of stroke are we talking about? taking the B18 to 89? why not use an LS crank and shotpeened stock rods with the appropriate rod fasteners for 8500 operation? I am sure that you will get results and not spend the cubic dollars to produce similar results that the Jun kit creates when tuned properly. I was just talking to someone on H/Anet who's buddy just did this when rebuilding his GSR motor. From what they say, it was a noticable improvment I dont know about 275whp from this setup... the above mentioned one I would guess had ITBs...


[Modified by MikeSarr_GSR, 8:27 AM 10/11/2002]

Bontke

Great info guys!!

That is what we all need.

advanceracing62- are you talking about a stroker kit for the b16 only or does all this good info(good RSR,retaining oil squirters, high revs) include the b18? How much more displacement are we talking? JUN have a website?

MikeSarr_GSR- the stroked GSR you were talking about, any dynos on that engine or torgue numbers?

advanracing62

www.junusa.com www.junauto.co.jp

you can get a stroker kit for pretty much any Honda motor from them, as long as you ask nicely and have the $$$.

MikeSarr_GSR

what I was talking about will be slightly more efficient than an LS/VTEC and alot more reliable. look at the LS/VTEC numbers/ and I am sure that will be close enough to expected gains

Lsos

I would think that when stroking a motor you should be more concerned about the inertial stresses on the motor than just the piston side loading. If you look at this graph:

https://honda-tech.com/zerothread?id=220704

you'll see that if you'd stroke a b16 to a 1.8 the pistons would be pulling almost 1000 gs more at the b16s redline. There's a reason why Honda didn't claim the LS could rev to 8000rpms. I'm sure it would still last, but not quite as long.

Also, I've heard of poeple actually destroking domestic motors to get better 1/4 mile times because the power potential is greater. Of course you said you don't want to rev to ridiculous levels all the time, so maybe a stroker kit is for you...

Choppa

Quote "Rod > stroke (long rod + short crank) will lower the squish velocity. A short rod + longer stroke crank will raise that velocity. So its better to stay below 1.75:1 for rod/stroke if your taste is NA."

this is wrong! Why do you think honda made the B16B. Same displacement crack as the B16, but taller block and longer rod.......because a longer rod for NA is desirable to increase torque in mid to high rpm applications.

Screaminz28

Alright, heres the deal. You can run a bad rod ratio at high rpms and make power. Too many honda dorks are out there claiming rod ratio to be a godsend in making power. There are only a few things that have to be done to make power. Maximize displacement; this is best done with bore, however, strokers came about from old v8s when you couldn't overbore a 350 to get the CID you want, so you make the stroke longer. Head flow and cams - make sure they flow good and the cams are matched, and you will make power. There is no hp made below the cylinder head. The pistons and rods are supporting characters to the head and cams. If you want to pretend to be an automotive engineer, talk about rod ratio. If you want to go fast, build a motor and forget about rod ratio. Don't think that the rod ratio issue has just arrived with hondas. Racers have known what it is, and the advantages and disadvantages of it for years. They just don't care, as their goal is not to minimize piston speed, or side loading, but to GO FAST.

Choppa

No one said you cant make power in high rpm with a low r/s.
I agree with your philisophy in regards to mating all components, and this is critical. To make power in the high rpm band with a low r/s you'll need the supporting cylinder head porting. Without this, the head will not be able to feed the appropriate mixture within the desired time necessary for an accelerating piston top.

Sure racers want to go fast, but they want to do it with reliability. Unless your name is Victor Bray (spelling) with copious amounts of sponsorship dollars with rebuilt engines after every race, then you'd want to make sure your beast is reliable.

btw, i am an engineer.

Screaminz28

I wasn't trying to offend you, as being an engineer, basically telling the honda populus that shouts "what about rod ratio" every time someone says something about modifying a honda engine. In response to high rpm power, someone earlier stated to limit rpm with a bad rod ratio to 6000 rpms. That is ridiclous. If it is built correct, then you can rev it fine. Also, if I am building a motor, for race, I would go even wilder than for the street, but honestly, do you see the negative aspects of a rod ratio of even 1.4:1 or 1.3:1 to hinder you from gettting the most power? I would rather have the power, and worry about the longevity of 100K miles reduced to 30K miles later. If I were honda, and had to worry about the longevity of an engine, I would think about it, and then change the deck height of the engine during R&D. I see many people talk trash about how ls/vtecs aren't good because of rod ratio. What? So its detrimental to run a 1.52:1 versus a 1.57:1 rod ratio in the ITR? Gimme a break. Honda dumped money into their engine designs for a reason. We are here to extract power, not reliablitly. Also, if racers wanted to go fast reliably, we wouldn't be seeing these stock block cars in the 10s. Its all about power, and getting there is the end result. Stop looking that the why so much, but the how.

Quick 200k Mile Motor

I stand firm on what I said in my first sentence. The second one, is soley my opinion.
Engineer or not? I am also one, but who cares!

easy.. Made for the CIVIC. Like I said, my statement "Its better to stay below 1.75:1 if your taste is NA" is my opinion. Lets swap a B16B into a Prelude.


[Modified by Quick 200k Mile Motor, 9:17 PM 10/13/2002]

Bontke

ScreeminZ28- HELL YA! I back that 100%. RS ratio has been blow out of porportion on this forum. If you want a 100,000 plus mileage engine then built it by the RS ratio. If you want to kick some *** with power then forget the RS (within reason) and then build a beast. Chances are that the car will be sold before it ever see's the life span of the built engine, or in my case, blow up or taken apart for a change in parts.

TimoneX

Anyone designing an engine buildup properly will not forget about R/S. If you forget about all that's said and just picture a crank spinning in a stroked motor it's not hard to envision the forces the crank, rod, & piston will exert on the cylinder wall as the rod comes closer to horizontal. Some of them stroker kits are dam expensive too, especially from Jun. You'd almost certainly get a bunch more for you $$$ boring it.

Bontke

It seems that boring the cylinder wouldn't produce as much torque as stroking. I used 2 examples at the begining of this post. I'm not saying totally blow off RS ratio, just within the small deviances mostly discussed on this board. Besides when are you most likely to put enough stress on the cylinder walls to make them give? That is alot of force and most of us here wouldn't have the engine stresses long enough to have that happen.