New feature: more drag analysis options

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tlcoll1
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New feature: more drag analysis options

Post by tlcoll1 »

I've updated the ECU+'s drag analysis to display different types of plots. Formerly, it plotted distance vs. time. Now it does that as well as speed vs. time and acceleration vs. time.

The acceleration graph is interesting. I put it in to see if I could figure out the best drag shift points somehow. My theory is that the best shift is achieved if the acceleration after the shift is equal to the acceleration at the instant you do the shift. Before the shift, acceleration is falling off. After the shift, it's increasing, so when they're equal you've shifted at the right place.

I'm going to test this theory out the next time I hit the drag strip in my car.

See the screenshot. The very first ramp-up hump is the launch. The 1-2 is the first big dip in acceleration. You can use the cursor and the track-back cursor to see exactly what the acceleration was just before the shift as well as just after the shift. In this case, the accelerations were 8.50 and 10.0 respectively. Since the after-shift number was higher, that means I should have shifted a little sooner. That "feels" right to me, since I shifted over 7000 RPM. The other big dips are the 2-3 and 3-4 shifts and I can apply the same approach on those. We'll see if this works out.

Tom
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burgers22
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Re: New feature: more drag analysis options

Post by burgers22 »

Great stuff Tom, never ceases to amaze me the continued support you give for this product. I almost think you like doing the development work on this.....
3" TBE, decat, Walbro 255, ECU+, K&N drop in.

tlcoll1
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Re: New feature: more drag analysis options

Post by tlcoll1 »

Since I'm an ECU+ user, I occasionally implement something that I'd personally like to have. That was the deal here. I do have one problem though. If I get a new car, I'm going to have to port the ECU+ to it, since I'd never be willing to accept an off-the-shelf item!

Tom

honki24
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Re: New feature: more drag analysis options

Post by honki24 »

So what are the units on accel? ft/sec^2? So you pulled about 1G on launch?
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tlcoll1
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Re: New feature: more drag analysis options

Post by tlcoll1 »

Right. The units don't really matter for my purposes, though - I want to see what shift RPMs are needed to "balance" the acceleration at the start and end of shift.

Tom

honki24
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Re: New feature: more drag analysis options

Post by honki24 »

I was just doing a common sense check. If you were running street tires I'd say that you're calculations are dead on as a street tire can handle only about 1g at best without loss of traction. If you were running drag tires or DOT R tires then I'd say it's a little off because you should be able to pull more like 1.5g on launch.
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