PacificDude

Ok, I've been doing some research and just can't seem to decide.

I plan on doing a B-series swap down the road in my '89 CRX Si. I will be boosting this motor FYI. Here are the two swaps I have in mind...

1) B18C1 (GSR)
2) LS/VTEC (B16 head w/ GSR internals)

In regards to option #1
From what I've gathered an OBD1 (94-95) GSR motor would be a better motor to turbo than a Type-R motor. The compression ratio of the GSR (9.98:1) would be better suited than the CR of the Type-R (10.8:1).

I have been told that high CR and turbo can coexist, but I'm not sure if it could be made street legal; that info came from a friend who has worked on race motors. I guess it could work with proper tuning, and if that is the case I find option #2 appealing.

Now, regarding option #2
Thanks to Snoopy for that link to the CR calculator. I've been playing with it a little bit and here are two setups I find appealing. B18A1 block, B16 head, GSR internals, and bored from 81mm to 85mm giving 1979cc of displacement. This yeilds(theoretically) an 11.14:1 CR. I increased the bore size to improve top end power and reducing the oversquare design: stroke larger than bore. Well, why not just go with the B20 block, B16 head, and GSR internals. By increasing the stock bore of 84mm to 88mm, keeping the 87.2mm stroke, and thus create a slightly undersquared design, the CR would be(theoretically) 11.79:1 and 2121cc of displacement.

My goals are reliable, streetable, lots-o-power, and only enough torque that I'm not losing traction everywhere I go.

I'd like to hear some feedback on what I'm considering for my swap. Don't ask what my budget is; think as if $$$ was not an issue here. Thanks in advance.

qtiger

If you're turboing don't bother with VTEC. Throw in a B18B and boost it. If you want more power, resleeve it and boost the piss out of it. Then, if you STILL need more power, go VTEC.

Yes you can boost a high CR motor, but don't do it with no experience and don't do it on a street car. It's so much easier to run a 9.5:1 CR and crank the boost a little bit than to run 11:1 CR and need extremely precise tuning.

Snoopy

the biggest bore you would want to go and still retain streetablity would be 84mm. it leaves room to overbore later if the cylinders are ever scuffed up. i dont even think 88mm with a b series would be possible. i've heard of 87mm with race only engines.

it would be a much better idea to just sleeve a b18 block.

PacificDude

Resleeving, blueprinting and balancing are part of the projects' scope. I want to do it right, so strong internals are an important step in my book. 84mm, I believe I've come across that limit somewhere, too.

At any rate, I guess I'll add that a high reving motor with a high spooling turbo is where I'm aiming at. So a turbo setup that can still perform well up to 9k rpm would be a target. So which head actually flows better: B16, ITR, CTR? Include port/polish to the variable.

qtiger

B16, ITR, and CTR heads are all the same. The ITR and CTR heads have a mild port and polish from the factory.

PacificDude

Well, I guess all things being equal I'll just get a cheap B16 head and use the money saved to have work done to it. Am I right to assume that a B16 head is better for high RPMs than a GSR head? That's what I remember reading in another thread somewhere.

Snoopy

they are both vtec heads so they both flow very well at high rpms.

97civicEXVTEC

i thought stock sleeves could handle 500+hp? so what would be the point of resleeving the block unless hes shootin for 30psi?

Snoopy

that's the exception. with very good tuning. i wouldnt recommend everyone go out and try for that much hp on stock sleeves.

would you rather spend $900 on sleeves now and have peace of mind, or a whole lot more later if you crack a sleeve cause you got boost happy?

PacificDude

Even if that were true, I would rather boost on new closed-deck sleeves than used stock sleeves.