for stock bore 81x87.2= 7063.2 / 4 = 1765.8 ?? right??

who can i calulate it for 84.5mm bore?

 

Here is a formula for figuring out displacement on a motor

Bore X Bore X Stroke X .7854 X #of Cylinders X .001 = Displacement

So.. I take it you are trying to take B18C to 2.0

81 X 81 X 87.2 X .7854 X 4 X .001 = 1797cc

84.5 X 84.5 X 87.2 X .7854 X 4 X .001 = 1956cc

There you go, hope that helped.

 

yes i am, I am very very confused though
Rod ratio and how that comes into effect..

Would it be best if i bored/sleeved my b18c5 block to 84.5mm
or get a

b16 bored/sleeved, i think would be fairly cheap
b20 bored/sleeved, bore this bitch to 2.2 liters , very expensive
b18c1 bored/sleeved, bore to 84.5mm more expensive then b16
b18b bored/sleeved, probadly cheapest, but will have to do lsvtec converison..

 

Rod/Stroke ratio in my opinion is overrated. If you're going to bore your ITR block to 2.0 you will be replacing internals which will help. R/S ratio shouldn't be a problem unless youre going to be revving over 9k or more regularly and some may argure that even that 9k and a little higher can be sustained with the stock B18C R/S. Stock for stock, due to the girdle, oil supply etc the B18C can withhold higher RPM than b18/20. But like I said that's stock for stock and can be made up for with extra work and some do it with out the extra work and have no problems. As far as the B16 bored... even with a 85mm bore youre at about a 1.8, if you're shooting strictly for displacement start with 1.8 or above.
If you wouldn't mind the downtime I would say bore your ITR block. But with enough money any of those block can be pretty nice

 

ill phil -- where did you come up with that formula?


[Modified by Zygspeed, 10:34 PM 10/3/2002]

 

yeah i most probadly will go with b18c5 block, i think blue printing and balancing will help me rev..

 

Well I picked it up a long time ago from ImportReview forums, forgot it, then learned it again in Autoshop class. And actually I still see 1797.


[Modified by ill phil, 3:37 AM 10/4/2002]

 

On the topic: how do you calculate gear ratio into speed?

 

Yeah, sorry about that, at first I saw the other number for the 84 mm bore.

 

ah, this must be star wars episode 5: Return of the Nerds

 

Hahaha yeah. I'm just waiting for another 5 page thread with people arguing over R/S ratio and which block is stronger because what.
Zygspeed: no problem I'm just jokin around, not trying to be a smart *** or nothin


[Modified by ill phil, 3:42 AM 10/4/2002]

 

hehe ...

however, soup doler.
what's your excuse?

 

man, you mean they dont teach cylinder volumes in school anymore?

Area * height = volume... i think i learned that in elem or middle school.

 

We is edgemicated

 

RS ratio will matter based on the type of racing that you do. Typically you would give up displacement (by giving up stroke) to increase your R/R. The current market moves wrist pin location to gain some RS ratio.

If you want a car with high HP then the higher RS ratio will help, if you want a car to accelerate from stand still really fast then you get less conservative on the RS ratio.

Do the cheapest route and go with b20 or ls/vtec and retain the 1.54 ratio, this is very effective in a street car.

Greg

 

In that formula,
"bore" X "bore" X "stroke" X .7854 X 4=
Where does one get the >".7854" from ?
would that number apply in a b17a engine's formula also? what about if your bore is increased to 81.25mm ...does that affect the .7854?.


[Modified by SpoonFanatic, 9:29 PM 10/27/2002]

 

Pi / 4 or 3.14159/4

Pi comes area of a circle calculation. The 4 is also from area of a circle calculation.

PS - I learned this in middle school