wsa111":3mv9l2ue said:
206 cubic inch engine - CI head with back cut valves - 390 4bbl - 11:1 compression ratio - 1.65 rocker ratio - 264/274-112*
I ran the same setup on both the 200 and 250ci.
206ci (60 over)
with 200cfm
231HP@5750 - 229lbs@4000 - 14.95 @ 90.1mph
with 250cfm
233HP@5750 - 231lbs@4000 - 14.90 @ 90.3mph
with 300cfm
235HP@5750 - 233lbs@4000 - 14.86 @ 90.6mph
with 350cfm
237HP@5750 - 235lbs@4000 - 14.82 @ 90.9mph
with 400cfm
240HP@5750 - 237lbs@4000 - 14.76 @ 91.3mph
with 450cfm
240HP@5750 - 238lbs@4000 - 14.76 @ 91.3mph
with 500cfm - up
no change
with single TB (500cfm)
245HP@5750 - 240lbs@4250 - 14.66 @ 91.2mph
with single TB (600cfm)
no change
with triple TBI's (500cfm)
250@5250 - 280lbs@3500 - 14.56 @ 92.5mph
with triple TBI's (600cfm)
no change
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257.7ci (60 over)
with 200cfm
280HP@5750 - 277lbs@4250 - 14.02 @ 96.1mph
with 250cfm
283HP@5750 - 280lbs@4250 - 13.97 @ 96.5mph
with 300cfm
286HP@5750 - 283lbs@4250 - 13.92 @ 96.8mph
with 350cfm
289HP@5750 - 285lbs@4250 - 13.87 @ 97.1mph
with 400cfm
292HP@5750 - 288lbs@4250 - 13.82 @ 97.5mph
with 450cfm
295HP@5750 - 291lbs@4250 - 13.78 @ 97.8mph
with 500cfm
298HP@5750 - 293lbs@4250 - 13.73 @ 98.1mph
with 550cfm
299HP@5750 - 294lbs@4250 - 13.71 @ 98.2mph
with 600cfm
no change
with single TB (500cfm)
301HP@5750 - 294lbs@4750 - 13.68 @ 98.5mph
with single TB (600cfm)
302HP@5750 - 295lbs@4750 - 13.67 @ 98.6mph
with triple TBI's (500cfm)
311@5250 - 346lbs@3500 - 13.56 @ 99.4mph
with triple TBI's (600cfm)
313@5250 - 348lbs@3500 - 13.51 @ 99.9mph
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Summary
With this setup, the best carb would be around 400cfm for the 200ci, or 500-550cfm for the 250ci. However, it is best to use a smaller cfm carb operating at high efficiency, rather than a larger cfm carb operating at a lower efficiency. It is also better to use a lower cfm rating if you want bottom end power, but more cfm for the top end.
With triple TBI's, more power at a lower peak rpm & better torque curve.
When a dual plane manifold is used, the HP is about the same, but nice gains in torque. What puzzles me is about the same ET, even with the extra torque. Therefore I think we need to do some dyno test and 1/4 mile runs with the new intakes and a couple custom adaptors.
I like to run some numbers with a turbo, but have no idea what to punch in. It ask for HP rating, CFM rating, and Efficiency. Any idea what these would be for a T4 with 10-12 lbs of boost?