09-21-2008, 05:10 PM
Join Date: Dec 2007
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Before and after dyno runs (NA 1.6L car)
I've always (well not quite!) wanted to see what difference a MSPnP without AFM made, compared to a stock ECU. I searched this forum and others without positive evidence...
If you're also curious about the answers to this question, read on!
The condition of the experiment were as follows:
- A 1993 (1.6l) NA car (Californian spec, thus with sequential injection when using the stock ECU)
- Randall CAI, stock air box bottom and air filter, TunerToy dual fuel rail, stock injectors, new plugs (some of this is probably irrelevant, but provided in the interest of science)
- Original exhaust but with high flow 2.5" metallic core cat
- Upgraded 1.6L clutch and torsen diff from a 1994 car, sticky tyres (185/60/14 Yokohama AO48)
- Same fuel (Euro 98)
- Same high precision MAHA dyno at the same shop (but measurements were taken with nearly two month of interval)
The dyno run on the second page of the attachement is based on the stock ECU and AFM, with timing bumped to 14degs BTDC... resulting in a whooping 84 BHP at the wheels, 96 lb.ft of torque (presumably at the crank)... and fairly low measured transmission losses (34 BHP).
The dyno runs on the first page are based on a MSPnP 9093, without AFM (I removed the AFM and top of the stock air box, and replaced this assembly with the MAF and air box cover from a 1.8L 94 car, which is supposedly less restrictive. I also drilled the air box cover to mount a GM IAT sensor in it)
There are two traces for torque and engine power on the first page. The thinner ones are with the default timing map, and the Thicker ones -slightly higher, especially at low rpms- are after tuning on a steady state rolling road (Timing was advanced by about 3-4 degrees at WOT)
Peak HP wasn't better with the MSPnP (82 BHP), but torque was significanlty better (106 lb.ft at best, and a much flatter curve, especially after tuning).
I'm a little bit perplexed by the change in Drag power as the setup was identical (yes, the tires were almost new when these measurements were taken, as opposed to almost worn in the other page), but this won't change the conclusions (whp is what mattters).
This is not quite what I expected on the peak HP front, but the torque gain an average whp gain of 5 BHP up to 6500 rpms are still nice to have...