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Dyno Session 12/11/03 Motorsport Dynamics
1986 SPG w/ T5 from a 9000 Aero
212hp @ 5500
248ft-lbs @ 3200
peak boost 20.1psi, holds at 14-15psi
Measured at the wheels, 60F, no corrections (I think).
Looks like things are good but they could be much better. The software doesn’t match the hardware – it's close enough to run, but not nearly optimized. Supposedly I have a reprogrammed ECM coming from SQR via Bo Engstrom that will cure this, but it’s been 2 months and no luck!
The dyno was not your regular roller-in-the-floor type. This one had two above-ground pods, and you removed the drive wheels and attach one pod to each hub. In this way (I’m told) a more precise measurement can be obtained, as you don’t have any squishy rubber tire between the motor and the machine. For car setup, first we calibrated the engine rpms to the wheel rpms. We picked 3rd gear as the test gear because I though it would minimize the chance of hitting the overboost cutout at WOT (wrong). Anyway, that took about a minute. The only data logging we did was the manifold pressure, because the other stuff was missing, broken, whatever. So I don’t have a nice Air/Fuel graph yet. And we took off the hood and set up a fan for the I/C.
The actual test was run from 2000-6000rpms, of course you can set these numbers however you want. The test starts with me “driving” in 3rd gear, 1500rpms, with no load. Then I engage right pedal WOT and the dyno magically holds the car to 2000 rpms – exactly. Over about 15 seconds, it steps up 500 rpms at a time, stabilizes at each level for a second, then moves on. I just hold WOT until it’s over.
So...what could be better? If you could see the graphs (still have to scan them), you would see the torque peak is exactly that - a sharp peaky shape due to the initial overboost to 20psi. After the ECM reels things back to 15psi, the torque is only 200-220 the rest of the way. A better-tuned T5 system should have a much flatter torque curve. Also due to the peak-boost-and-recover, the hp curve has a flat spot between 3200-4000 rpms. The hp curve is nich and smooth though, waaaayyy better than before with the LH2.2.
Next up: new .63A/R turbine housing, fabricated airbox, new computer (where the heck is it?), some attention to the fuel pump (might be going), more dyno time.
posted by 12.72.15...
, Fri, 12 Dec 2003 18:16:18
, Thu, 11 Dec 2003 21:06:38
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