Project_SOHC_EX

For any of you that might know. What does increasing the stroke from say 87mm in a B18a1 to 92mm do in terms of performance?

Project_SOHC_EX

Is anyone going to respond?????????????? Please I'm in need of some serious opinions here

FuzzyGreen

Well it will lower your rev limit due to piston speed but will give you more torque and power throughout the lower and mid rpm ranges. Performance might decrease in the higher rpms.

DIRep972

iTrader: (1)

why would u want to do that? If you had a longer stroke crank w/ a longer rod/deckplate you could maintain your rod/stroke ratio and increase the displacement at the same time........ but! its really not nessacary on a turbo car. Stock GSR/LS crank is all you need for 1000whp w/ the right turbo set up.

Mr. Softee

most likely changing your stroke or bottom end geometry is going to be overcomplex and a waste of money.

DIRep972

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94goldjungsr &raquo;</TD></TR><TR><TD CLASS="quote">most likely changing your stroke or bottom end geometry is going to be overcomplex and a waste of money. </TD></TR></TABLE>

WERD!

ahobbs

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIRep972 &raquo;</TD></TR><TR><TD CLASS="quote">

WERD! </TD></TR></TABLE>


that's to much for me to think about. I don't get paid to have a fast car. I pay people!

pornstarSR

by increasing stroke you change a few things...

rev range changes to lower, even though you can rev it to 9000 but the pistons speed is gona be pretty high...

also you need a custom rod if your not gona deckplate

but all in all the idea of increasing stroke gains you torque for the jist of it

http://www.crower.com/cat/impo...shtml check this out

the only thing is i havent presonally had any experience with crowers stroker stuff...

the liters is what its all about too, displacement.....more displacement more power

its complicated, lots of things change when you stroke a honda

Mr. Softee

or you could spend all that money on sleeves and a better fuel system and turbo and just up the boost and make a ton more power.

DIRep972

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94goldjungsr &raquo;</TD></TR><TR><TD CLASS="quote">or you could spend all that money on sleeves and a better fuel system and turbo and just up the boost and make a ton more power.</TD></TR></TABLE>

EXACTLY!

pornstarSR

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94goldjungsr &raquo;</TD></TR><TR><TD CLASS="quote">or you could spend all that money on sleeves and a better fuel system and turbo and just up the boost and make a ton more power.</TD></TR></TABLE>

yeah getting a custom crank is not cheap...

turbos are the great honda replacement for displacement

FuzzyGreen

Take it from someone that owns the longest factory stroked B series, IT'S NOT WORTH IT. 95 mm stroke and only about 10 lbs/ft more torque then a B18a/b. This thing runs out of air after 6k rpms.

Muckman

iTrader: (2)

http://www.crower.com/cat/impo...shtml

They want to charge $1500 extra for a billet crank over the forged crank! Is it just me or is that insane?

Also note it says wait 4-6 months for the crank lol

Id have to agree with everyone above, it seems like alot of money for little gain. Just boost more and all is well. If you want a longer stroke, you shoulda went with a domestic, not a honda.

Project_SOHC_EX

Thank you all who participated in my discussion topic. This is one of the few times where I have gotten all negative responses to one of my turbo ideas. The idea of my motor running out of breath at 6k wouldn't be too good for a turbocharged application. Thanks fellas, I really appreciate the comments and info.

Mr. Softee

theres no way the car will run out of breath at 6k with an LS crank. that is an issue with your tuning or head... therse tons of ls/vtecs making power over 8500

Project_SOHC_EX

FuzzyGreen do you care to comment on this individuals statement?

DIRep972

iTrader: (1)

guys he is talking about his prelude. hence 95mm stroke.

FuzzyGreen

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Project_SOHC_EX &raquo;</TD></TR><TR><TD CLASS="quote">FuzzyGreen do you care to comment on this individuals statement?
</TD></TR></TABLE>

Well he somewhat has a point, it's very possible my engine's head or intake manifold is restrictive, but even with 5psi boost it looses power above ~6500 rpms, which should show that it isn't all about breathing.

Besides an LS/VTEC still has a WAY shorter stroke then 95mm. I have owned a B18b and a ZC and they pulled WAY better on the top end then my B21. Modified or not.

There is a reason Honda went with a shorter stroke on the vtec motors. Piston speed and high rpm breathing. At a high rpm you cannot fill the long stroke cylinders whereas a short fat cylinder (F1/motorcycle engines) will have plenty of time. The opposite it true at low rpms where the long stroke sucks in way more air cause it has time to pull it in.

Mr. Softee

ahh i didnt know you meant the old prelude crank. i was thinking b18b/a crank.

im sure that does drop off a little as piston speeds are extremely high at high RPM. Still at 5psi most turbos are going to run out of breath above 7k anyway.

Quick 200k Mile Motor

most of us already know that increasing the stroke shifts the VE down (earlier torque production and compromises the highend),
but something else might want to consider: Traction.

In a FWD, it's more suitable having a motor with most of the power in the mid to upper rpm range instead of down low.
It would be impractical for most power to be applied at low rpms (unless you like burn-outs) .