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Old 05-25-2015, 06:11 PM   #101
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Originally Posted by Mobius View Post
Sean one thing to keep in mind here is you are running the -74 on a 1.6, so you will see higher PSI for a given compressor speed than a 1.8.

With the 80mm, on the stock engine I saw about 8psi, 191whp/156wtq.

With the built engine / CNC head, 6.5psi / 217whp / 166 wtq.

It seems none of us can replicate early power measurements with the C30-74.
Bellwilliams track car: "We made 230whp with the same set up at 7000rpm, 110krpm and a 1.6" restrictor (blower inlet ID is 2.375")." I don't recall which dyno they were using for that car.]

I am actually running a 1.8, specifically a NB1 motor with a BP5a intake cam. So the boost pressure numbers I am reporting are for the 1.8 :-) I have a local dynojet which seems to be inline with the numbers the 949 guys were producing. Once I have time to actually get over there, I'll have some 91 octane numbers before I switch back to E85.

The old dyno numbers for bellwilliam's car were from a Superflow dyno, here is a sheet that was posted before on It's hard to say how this dyno comapres with the typical SoCal dynojet. Bellwilliam was also running what looks like a 12psi pulley configuration (with restrictor) due to the boost graph leveling off up top. This plot is also from when he was running E85, I believe this to be a key to making big power on the -74.

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Last edited by Lincoln Logs; 05-25-2015 at 06:27 PM.
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Old 05-25-2015, 06:49 PM   #102
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Such a boring torque curve though.
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Old 05-25-2015, 07:03 PM   #103
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Sorry Sean, I thought you were still running a 1.6 due to the "Scooby: Rotrex powered 1992 NA6" line in your sig. My bad, obviously reading comprehension fail on my part
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