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JB3 VS V3 .. which one is best ?
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10-22-2009, 04:43 PM | #265 | |
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10-22-2009, 04:59 PM | #266 | |
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The real long term risk with this platform is turbo failure. And in that arena the JB3 offers a more comprehensive two-layer hardware and software based safety system. As time goes on you will be hearing a lot more about engine failure as the result of compressor failure than blown head gaskets or ring lands. On CPS datalogging, I have plenty of V3 and JB3 logs showing interesting and surprising things. I can bump the thread or repost them here if anyone is interested in discussing them. At the time all the technical gurus seemed to take the week off. Mike |
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10-22-2009, 05:03 PM | #267 | |
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Even if I conducted the test w/ Shiv, people will still have doubt behind the testing methods - debate will still follow. The debate will only end when someone with a JB3 pops a headgasket or puts a hole through a block. That is why I asked Shiv to send the logs to me, for my own education. You are fairly local, why don't you run the test with him? It looks like he has a JB3 on hand. |
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10-22-2009, 05:13 PM | #268 | |
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Can you bump those threads? Thanks! |
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10-22-2009, 05:15 PM | #269 | |
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Besides, Ive already run a JB3 in my car. I already know what it does and how it does it. I don't need any more convincing. Junk
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11.647@121.356mph (1.590 60') - AutoTune (beta pre-5-15), Race Gas, No METH Perf Mods: Vishnu PROcede Rev3 v5, Vishnu PWM Meth Kit, AR Design DPs, AE Exhaust, Helix FMIC, Vishnu DCI, Forge DV, WaveTrac LSD (Best Trap - 124.665mph) |
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10-22-2009, 05:42 PM | #270 |
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I'll just post the original logs here for reference. The debate focused on whether or not timing drop outs were reduced/prevented with CPS as implemented, and whether timing drops always indicate knock retard. As often happens people were more focused on the colors in the chart than the actual data. Which to me was very interesting. The test car was BMS' 135i with 91 octane fuel, ~100 degree ambient, default Stage 3 maps for the V3 and map 7 for the JB3. Basically aggressive setups on 91 octane fuel in hot weather. Worst possible conditions. The V3 logs do not reflect the timing the V3 is taking out via CPS as the timing advance is read right from the DME. So actual V3 timing is 3-4 degrees lower. In the end, both systems were running almost identical actual timing and exhibited similar drop outs.
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10-22-2009, 05:45 PM | #271 |
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In addition to those logs I just posted, here was some supporting data on the discussion of whether timing drop outs actually represent knock. Or something else. To prove this point I took dynos published by Vishnu themselves and their corresponding logs. It just didn't add up. Serious knock on the logs, yet smooth charts. So there is something else going on here IMHO.
Mike |
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10-22-2009, 06:14 PM | #273 | |
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Here's the funny thing about tuning: When you know something about it, it all makes sense. When you are on the top of the MBT curve, torque output is reasonably insensitive within a reasonably wide range of ignition advance. There are plenty of books on the subject. Not the best substitute for experience but it will do in a pinch. shiv |
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10-22-2009, 06:57 PM | #274 |
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Mike, thank you for the logs! Aside from seeing, at the time, JB3 had better boost targeting control - timing advance from both tunes are fairly similar in profile. That is why I get confused when it is mentioned that the Procede will knock less w/ CPS offset.
What is strange to me is that the timing drops occur roughly at the same spots in the powerband regardless of tune. I saw the same drops in Scalbert's series of logs back when he was testing both the JB3 and V3. The only time I don't see those drops are with the stock timing advance profile. Last edited by mmmotornutz; 10-22-2009 at 07:26 PM.. |
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10-22-2009, 07:19 PM | #275 | |
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Mike |
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10-22-2009, 07:27 PM | #276 | |
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10-22-2009, 08:10 PM | #277 |
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FWIW from my experience and what others have posted there is always a timing drop at ~4500 rpm on tuned cars. I think we all hypothesize that it occurs there due to the vanos timing shift. But, a stock car doesn't do that. I think most of us that datalog ignore the 4500 rpm timing drop as indication of knock. Now, when it occurs elsewhere, that's a different story.
As far as adaptation and the DME increasing timing making CPS offsets irrelevant, I totally disagree from my personal experience. I did 5 back to back third gear pulls and the timing from 4500 to 7000 rpm were right on top of each other and did not "creep up" to the DME "uncorrected" timing curve. I also believe there is a limit to how much timing the DME can add, so the procede can prevent too much timing advance with the CPS offset (which prevents knock from otherwise occurring). |
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10-22-2009, 08:50 PM | #278 | |
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Your last statement can be true if we assume the DME doesn't advance until it either hits a maximum value or knocks. |
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10-22-2009, 10:52 PM | #279 | |
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