Dont flame me for this? Im an all motor guy that is likely switching to forced induction after I learn about it.

I have a B17A, and a B20B motor. Which would be best to run? And why?

Is Vtec really significant in any way when it comes to boost?

 

Ever hear there's no replacement for displacement? It's true for the most part. I'd boost the B17 (personal preference) and save the b20 for a build-up out of the car. Vtec makes a big difference when under boost. Some people argue this for some reason. Why, I don't know. The biggest power makers right now are the Vtec's.

 

84mm flat tops + vtec + boost = fun on the streets.

 

 

all other things being equal (i.e. put the vtec head on the b20 and raise the compresion) a 18% displacement increase will make aprox. 18% more power...

the b20 vtec will definately be faster, but cost a lot more.. if you are wanting to keep the motors stock then I would also do the b17

 

Honestly I'd run the B17 right now and save the B20 for a build-up. The B17 is a very freindly boost engine. Kind of an odd ball though. It has a better R/R ratio than the B20 or even a GS-R/ITR, that means a happier revving engine. It also has about the compression of an LS, which mean you can get away with prolly 10-12lbs on that engine before you'd really have to worry about you internals.........if it's tuned well of course.

Once you're tired of the setup, go ahead and build the B20 bottom-end up and then slap your B17's head on there and you'll be good to go for some serious fun. **After thought, you could also swap over the B17 crank into the B20 block and run some custom rods. THis would allow you to keep the nice R/S ratio of the B17, and use the larger bore of the B20. Think about being able to rev that B20 just as high as a VTEC engine WITH boost **

Oh and displacement does make a difference, but the B20's low 6500 redline and non-perforamce oreinted cams don't help much. When I built my LS into a 2L engine, I found that at 8psi of boost I needing just as much fueling as I was at 10psi on the 1.8L setup. That means with nothing else but the increase displacement i'm making the saem amount of power @ a lower level of boost.


[Modified by Speed PHreak, 11:23 AM 12/13/2002]

 

if you do choose to run the b20 with boost be sure and at least put some arp rod bolts in it. ive seen those weak b20 rod bolts make metal soup in the oil pans, not pretty. but like others have said build the b20.

 

Thanks for the input guys.

What I plan on doing is running the B20 but getting it resleeved. Using 84mm Arias pistons with Eagle rods. Other than the usual tuning of fuel and such, I want to run 16-18 lbs of boost on this motor.

Now, me not being an expert at forced induction, I dont really understand why Vtec would help significantly. In a N/A application I can, but why under boost as well?

I have both heads, CRV and B17A head. If I end up using the B17 head and revving to 8000-8200rpm, should I install the oil squirters in the B20?

From what I understand the oil squirters MAIN purpose is to cool the cast piston. So would they be needed if I am running a forged piston?

Again, thanks for the input.

 

For a modereate boost engine go with the B20, if you are intending to run a high boost or boost and n2o the B17 maybe be a better bet.

The shorter stroke of the B17 results in less side loading of the piston and tehnically should allow higher cylinder pressures.

But it cant be denied that there is no replacement for displacement...

 

b20.b20.b20....ever heard of going bigger like 2.2 b-series for the street. Any interested?

 

That ought to be fun

VTEC heads generally flow better than non-VTEC heads. The valves are larger inVTEC head as well. They're made to rev higher and indure higher RPM's for longer durations. That in itself is a bonus just the have the higher flow. Plus on par VTEC's make more HP than they're non-VTEC counterparts. Basically VTEC kicks in after most t3/t4's spool and gives some added flow.

Myself, i'm happy with my non-VTEC engine. I rev to 8K and make plenty of power, though I run a crower top-end with custom spec cams. It's what i'm used to and works for me. Plus VTEC is just one more thing that i'd have to tune that i'm to damn lazy to


You're correct about the oil squirters, most times they're not need on engines with forged internals. As the aftermarket stuff usually cools a hell of a lot better than the stock stuff. Although I think most factory turbo engine have oil squirters, the nissan SR20DET, the Toyota 2JZ-GTE , and the DSM 4G63 all have them.


[Modified by Speed PHreak, 2:40 AM 12/14/2002]