Sunday, May 25, 2014

Dyno day

Before I pull the car apart to finish the body I wanted to put it on the dyno to get a baseline of how the motor is running. When driving around it felt a little down on the power I was hoping for, and it went flat after 4500rpm, about 1000rpm sooner than it should with its hydraulic flat tappet cam. So I borrowed a workmates sweet wagon (cheers Max!), rented a trailer, and towed the cuda out to see the rad dudes at Speedtech Motorsport.

It got bolted up to the Dynapack hub dyno...

and put through its paces a few times. Sure enough the power curve fell off at 4500rpm, but it pulled real hard up to that point, so it turns out I'm just greedy! It put out 444lbft to the rear wheels at 4100rpm, so well over 500lbft at the motor and should do similar hp once I find out what's causing the power to drop off 1000rpm too soon.

I unbolted the temporary mufflers and removed the little air filter hoping they might be causing the power drop, but no luck. The motor did put out 30 more hp to the rear wheels without those little 2.25" mufflers though! And holy shit it was loud in the dyno room with open headers! Diagnosing the power drop issue will have to wait till the car is going again in the future, but at least it's good to know it's running great till 4500rpm. That's straight outa the box too, with conservative ignition timing and no carb tuning. So it should be an animal once fully dialed in!

2 comments:

  1. It looks like it could be valve float, what springs are you running?

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  2. Valve springs are new Comp Cams dual springs matched to the cam.

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