Piggy back goes oink oink...

[sakimano]

I have some Revo logs that don’t show any timing pull after several back to back strip passes ;D Didn’t end to well for that motor though…

please tell me those weren’t recent

that was 2 years ago I believe. Interestingly they are now kind of conservative with ignition timing advance.

Actually I also have recent logs from a Revo stage 1+ car that didn’t pull any timing on three back-to-back dyno passes. I’ve posted the logs here in my dyno thread. The APR and GIAC cars pulled between 2-6 degrees for the most part. Revo did open the bypass slightly, and there was a long debate on both sites about what it really meant (how safe). They were at least as aggressive, or more so, with their timing as the other tuners, and they were the only ones with no knock correction. They came back with several long winded explanations for why it’s tuned that way.

you’re talking about retardation. I’m talking about their calibration for timing advance. Different thing.

They used to request considerably more timing. Then they’d dumb down knock sensors and instead bleed boost. They still seem to do that, but they aren’t requesting such high levels of timing.

Remember tsivas posted the logs back in the day of the REVO pump file requesting same timing as the APR race file?

[jran76]

I have some Revo logs that don’t show any timing pull after several back to back strip passes ;D Didn’t end to well for that motor though…

please tell me those weren’t recent

that was 2 years ago I believe. Interestingly they are now kind of conservative with ignition timing advance.

Actually I also have recent logs from a Revo stage 1+ car that didn’t pull any timing on three back-to-back dyno passes. I’ve posted the logs here in my dyno thread. The APR and GIAC cars pulled between 2-6 degrees for the most part. Revo did open the bypass slightly, and there was a long debate on both sites about what it really meant (how safe). They were at least as aggressive, or more so, with their timing as the other tuners, and they were the only ones with no knock correction. They came back with several long winded explanations for why it’s tuned that way.

you’re talking about retardation. I’m talking about their calibration for timing advance. Different thing.

They used to request considerably more timing. Then they’d dumb down knock sensors and instead bleed boost. They still seem to do that, but they aren’t requesting such high levels of timing.

Remember tsivas posted the logs back in the day of the REVO pump file requesting same timing as the APR race file?

I’m actually talking about both. Their requested timing was still higher than APR or GIAC by at least 3-4 degrees. Maybe not quite race gas levels, but also definitely higher than the other tuners. On the day we did the testing, Revo topped out at 22 degrees, and APR and GIAC both topped out at 18 degrees. Revo had no knock correction, APR had 2-3 degrees, and GIAC had 5-6 degrees.

[cobrario]

Revo had no knock correction, APR had 2-3 degrees, and GIAC had 5-6 degrees.

I’ve read through Jeff’s posting of Robin’s reply and it seemed logical to me- but I’m not nearly as versed as you guys are. Are you suspecting that Revo still desensitizes the knock sensors?

[jran76]

Revo had no knock correction, APR had 2-3 degrees, and GIAC had 5-6 degrees.

I’ve read through Jeff’s posting of Robin’s reply and it seemed logical to me- but I’m not nearly as versed as you guys are. Are you suspecting that Revo still desensitizes the knock sensors?

A lot probably depends on how you define desensitizing the knock sensors. I wouldn’t use that exact terminology, but in the most basic sense they are doing something along those lines, and fully admit it.

Per Revo’s Engineer/Calibrator (Robin):
The stock strategy is EXTREMELY conservative with how it responds to knock. When it picks up a little bit, it will pull out MUCH more timing than is necessary, creating higher EGTs and a sloppy curve. We modify the factory strategy in a way that keeps the factory safety routines in place, but changes the response loop so it will pull less timing and add it back in quicker. It’s not “turning off the knock sensors” as posted above.

The data also bares this out. If you are to believe what they are stating, it does seem logical, and at over a year in there have been no known issues with their approach. Back to the point made by the engineer that doesn’t trust engineers… I guess it depends on how much you want to trust the engineer/calibrator in this case.

[b5b4b8]

OK, so my question is why is this thing so sensitive to octane? Sensitive to altitude?

First, for altitude, is it due to the increased pressure differential between nominal and boosted? Is there are reason why a roots style supercharger would do this? In stock config, the car should just hold the bypass valve closed till higher RPM to reach the normal target boost pressure, correct? So the low end on a stock car will be worse, but at top end the car will show similar performance (in terms of power)? Or a positive displacement blower doesn’t do this?

I think you are on the right track - at higher elevations, since you are starting with a lower atmospheric pressure, you need a higher pressure ratio from the blower - which moves you into a less efficient area of the compressor map vs. if you were at sea level. As a result post-blower temps will be higher than it would be at lower alt (or lower pressure ratio), which makes having a higher octane fuel more critical. Plus you are running higher overall compression than the ECU is expecting since you are feeding it incorrect pressure, the timing is more aggressive than stock. Seems both of these would lead to octane sensitivity… ???

I’d still like to know if this thing modifies JUST the pressure signal, or if it also does that trick on the IAT signal as well.

[drob23]

Here’s your CW tech support, pretty cutting edge, they even tune fire trucks: https://docs.google.com/forms/d/11hK3qvApj4Ah0N7_LXCqg0gv5U8LnJgVvQktA2TKsew/viewform

This is approaching “lulz at other forums” levels

[angrodri]

Here are several back to back 3rd gear pulls for the peanut gallery

-2015 S4 DSG
-ChipWerke Pro D1 setting
-93 Octane
-73F
-800’ MSL

https://dell.box.com/shared/static/b0wgd43py8zm60fpp2eryxp12bxywt9b.csv

Cheers

[sakimano]

Got a pbox?

[angrodri]

Nope, but it feels fast! . I’m going to get a P3 though.