Back from the Dyno !
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Joined: Aug 2001
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From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
Re: Back from the Dyno ! (GrandSportC3)
Ratman: It could be the intake or the cam. With a 468 in motor a cam with mid 240's at .050 will top out in power about where yours did. My old combo was a cam that was 242 and 248 at .050 with a Rpm Air gap and it topped out at 5850 on the dyno. If the power did not drop off too much from 5600-6000 rpms it is a bit of a testimate to the heads flowing pretty well.
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Joined: Oct 2000
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From: Allen TX
Re: Back from the Dyno ! (69 N.O.X. RATT)
You guys know a lot more about BB power than I do, but why does it seem like the cam is always too small? ;) My combo has a much smaller cam (230/230 hyd. roller) and makes more power with about the rpm band. I'm also only at 9.5:1 CR, which is probably less, too.
Power only falls off 20hp from where it peaks at 5600 to 6400 where I just shut it down. That's not much of a drop either for an 800rpm span.
My only guess is that his Merlin heads might need more cam than my AFR heads? Then again, a better intake may be the ticket. :)
Power only falls off 20hp from where it peaks at 5600 to 6400 where I just shut it down. That's not much of a drop either for an 800rpm span.
My only guess is that his Merlin heads might need more cam than my AFR heads? Then again, a better intake may be the ticket. :)
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Joined: Oct 2000
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From: Allen TX
Re: Back from the Dyno ! (Fevre)
Fevre,
I hear ya. However, I have not seen much difference power-wise b/w a hyd. flat tappet and a hyd. roller. Obviously the hyd. roller means less maintenance, and slightly more aggressive ramp rates, but I'm not sure for milder applications it makes _that_ much of a difference. At least it doesn't in the tests I've seen. Solid roller makes a significant difference, though. :)
I hear ya. However, I have not seen much difference power-wise b/w a hyd. flat tappet and a hyd. roller. Obviously the hyd. roller means less maintenance, and slightly more aggressive ramp rates, but I'm not sure for milder applications it makes _that_ much of a difference. At least it doesn't in the tests I've seen. Solid roller makes a significant difference, though. :)
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Joined: Aug 2001
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From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
Re: Back from the Dyno ! (WA 2 FST)
Wa 2 fast: Your AFR heads are much better, also your hydraulic roller is a few degrees shorter, but don't forget because you have zero lash and he has some that has to be made up your cams are more similar. Generally this fact makes a hydraulic cam "Act" 8 degrees or so bigger. Then you add in the far more aggresive roller ramps and you have the reason for the differance in power. Then there is always the fact that no two dynos are the same, the only real way to tell is take them to the track and see what kind of MPH they will post
