Chip Testing on 100 octane - ABT vs. giac XR (long write-up)
01-16-2003, 08:41 AM
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Chip Testing on 100 octane - ABT vs. giac XR (long write-up)
Last night I tested a giac XR against my current ABT chip, collecting various data with the VAG-COM. These are 3rd gear downshift runs on same stretch of highway, same car, about 20 min apart (ABT first, then XR). Temps were about 15 deg F. Tank had mostly 100 octane (figure about a 98 net in all fairness)
First lets look at boost. The XR has more, no big surprise. By the way, these graphs start at a common RPM point when both cars had fully spooled / hit peak boost after the downshift.
<img src="http://pictureposter.audiworld.com/16111/abt_xr_boost.jpg">
Next we have timing advance. This was a real eye-opener. I've long suspected my ABT does not optimally advance timing for 100 octane as some might say, as I get close to the same advance running 93-94 as I do 100. Here's the graph:
<img src="http://pictureposter.audiworld.com/16111/abt_xr_timing.jpg">
Yeah, wow. In a couple later runs playing with the XR I even surpassed 30 degrees advance above 6000rpm @ WOT.
Finally, I checked acceleration using delta T in the VAG logs. On the butt-dyno the XR felt faster, and the data confirmed. I probably should have swapped the x-y axis, but you can see a lower slope means it's quicker (less time to hit X mph):
<img src="http://pictureposter.audiworld.com/16111/abt_xr_acc.jpg">
I calculated the XR pulled at least a car length on the ABT in this short 3-4 second highway sprint, which is pretty significant. And at that point the XR is pulling a 1/2 car length per second on the ABT, so it's walkin away pretty good.
Other observations - the XR does not feel as refined or smooth as the ABT while cruising around, although I only got a chance to spend 15 min with it so I'll give it some more driving time. I have a feeling that for everyday driving, I'm gonna like the ABT better (but then XR is a race chip after all, right?) But as far as which is faster, XR without a doubt, it's brutal. And I also believe running 100 on an ABT is a waste of money.
First lets look at boost. The XR has more, no big surprise. By the way, these graphs start at a common RPM point when both cars had fully spooled / hit peak boost after the downshift.
<img src="http://pictureposter.audiworld.com/16111/abt_xr_boost.jpg">
Next we have timing advance. This was a real eye-opener. I've long suspected my ABT does not optimally advance timing for 100 octane as some might say, as I get close to the same advance running 93-94 as I do 100. Here's the graph:
<img src="http://pictureposter.audiworld.com/16111/abt_xr_timing.jpg">
Yeah, wow. In a couple later runs playing with the XR I even surpassed 30 degrees advance above 6000rpm @ WOT.
Finally, I checked acceleration using delta T in the VAG logs. On the butt-dyno the XR felt faster, and the data confirmed. I probably should have swapped the x-y axis, but you can see a lower slope means it's quicker (less time to hit X mph):
<img src="http://pictureposter.audiworld.com/16111/abt_xr_acc.jpg">
I calculated the XR pulled at least a car length on the ABT in this short 3-4 second highway sprint, which is pretty significant. And at that point the XR is pulling a 1/2 car length per second on the ABT, so it's walkin away pretty good.
Other observations - the XR does not feel as refined or smooth as the ABT while cruising around, although I only got a chance to spend 15 min with it so I'll give it some more driving time. I have a feeling that for everyday driving, I'm gonna like the ABT better (but then XR is a race chip after all, right?) But as far as which is faster, XR without a doubt, it's brutal. And I also believe running 100 on an ABT is a waste of money.
01-16-2003, 08:56 AM
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why did both the abt and xr on race gas get me 2/10's at the drags last year? so,
do you think i could have ran the same with just pump gas in on abt? well, what i mean is, what is the highest octane i can run on abt for it to stop making a difference?
this explains my slightly higher trap speeds on xr....actually, that would have been a 12.7 if my launch was the same as the abt...hmmmmmmmmmmmm......what should i take to the strip this year?
nice job darin
mike
this explains my slightly higher trap speeds on xr....actually, that would have been a 12.7 if my launch was the same as the abt...hmmmmmmmmmmmm......what should i take to the strip this year?
nice job darin
mike
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01-16-2003, 08:57 AM
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The boost is within spec on the KO3 compressor maps and timing...
Run as much as you can without having high egts and high knock sensor values...I think Piggie did a post in the past that showed the XR actually had less EGT than the ABT on race fuel! If you notice the boost and timing maps garrett adds timing in as the boost decreases to stay within spec, this leads to very linear("brutal") power delivery right ot redline!
01-16-2003, 09:00 AM
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Hey Mike! Yeah, perhaps under track conditions the 100 helps (heatsoaked)?
All my testing has been road testing in quick spurts, so ICs are cooled down and don't have a chance to heatsoak