Okay so lets start off with a scenario

Hypothetical situation:

The engine is a b16b, it uses a b18c block with a rev happy 1.83ish r/s ratio.
The stroke is 77.4mm
The bore is 81mm
The Trans is the CTR/USDM ITR/3.23/2.105/1.458/0.848 with 4.4 final drive


Now if one had a vehicle equipped with a b16b and wanted to achieve greater acceleration, a common swap is a "ITR stroker kit" which uses the 87.2mm crank and shorter rods, which brings the r/s down to about 1.58.

By doing this we are increasing the stroke from 77.4 to 87.2, which is a 12.6% increase in stroke (as well as 12.6% increase in displacement) The same redline of 8500 is kept. However due to the 12.6% increase in stroke the pistons are moving 12.6% greatever volume at 8500 than they were with the 77.4mm crank.

Now lets bring gearing into the equation, a readily available final drive option is the 4.928 final drive. This is exactly 12% shorter than the stock 4.4 final drive.

So when we have a b16b with a 4.928 final drive compared to a stroked b16b with a 4.4 final drive at any given speed they will be moving within 0.6% of same amount of volume.

So lets say that we rev the b16b higher, exactly 12.6% higher. This gives us a 9576rpm redline

without bringing cams into the equation (again this is for hypothetical and theory purposes only) Which is better?

 

Why rev it to 9.5? Not making any power...

clean rice can chime in a little bit. He got his M22X's and MF gear set from me.

 

Bump! Good question Bense

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i have a tranny w/ full ATS gears and 4.9fd w/ quaife LSD, i'm planning on mating it onto a stock 96 spec b18c ITR motor and keeping oem reliability on the road course while still being faster (i hope)

in for an answer

 

I would perfer the b18c, because thet engine will requires less mechanical work to produce the same amount of torque. Also, the issue of proper oil control and longevity of the rings becomes a greater issue at those high rpms. One other thing, would be the selection of rod and bolt materials. 9k+ will require a significant step in material grade, if this motor is going to last 100K+ miles.

 

nice thread...in for some answers!

 

I have a 16b and wonder ofter whch route to go...stroker or tranny

 

Both.

 

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Good call!

 

interesting "Hypothetical situation" sir.

subscribed!

 

would this set up be better or pretty much one in the same.
The increse in displacement giving the 12 % increase in airflow and the engine with the tranny flowing more at more rev's would their rate of accelerating be the same just in different areas of their "power band" netting you the some results, but would the smaller engine struggle more with air resistance than the stroker motor would due to the torque increase

 

The final drive doesn't affect flow or power. Just gets you through the gears quicker.

 

its more about torque and gears than horsepower, horepower is just a function

 

torque is what moves you through the gears, shorter gears allow you to move across your powerband faster across those gears, bense your the man you know better than most of us

 

bense what would this vehicle be used for? drag?autox? dd street car?