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      02-24-2011, 10:20 PM   #96
Forced Induction FTW!
roninsoldier83's Avatar

Drives: E90 BMW 335xi N54 6MT
Join Date: Oct 2010
Location: Denver, CO

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Originally Posted by View Post
Like I said this platform is pretty unique. Get ready for 14.5:1 air/fuel ratios @ WOT and 5-10 degrees advance @ WOT. The maximum advance set points are based on load, rpm, but also gear, iat, EGT, etc. Then you have the long and short term learned factors that play in. Generally with a JB3 on pump for example the long term octane adaptive is maxed out negative which takes away 2-3 degrees of advance. Which is why you have thousands running tens of millions of miles without knock related damage, ping, or even bad looking plugs. And that is using the old logic that could not even listen for knock / drop outs. The new JB4 logic is going to prove much better. When the ATR comes out it will be interesting to see the actual knock related tables and how it all really works. There may be factors that play in that we're not aware of. But make no mistake, it does work perfectly well as many JB4 logs posted have already shown.

The thing is Mike, as shown above, base timing is still controlled by a very simple and universal concept- a load vs RPM table, just like most other modern vehicles. You might not realize this, but pretty much all modern performance vehicles have temp sensors (that sense IAT's either via MAF or MAP), and they have compensation tables for IAT's as well. Many cars don't have gear specific maps/boost settings (however there are means of tuning cars that way outside of the BMW community), but at the same time if based on a preset WGDC value, as load increases (aka higher gear), so does boost, so in essence, most tuners realize this and typically tune in a higher gear (3rd, 4th or occasionally 5th depending on the ratio of the gear) in order to attempt to tune under a full load/boost.

The reason why a person sets an ignition timing table is so that under different load & RPM conditions, the ECU knows how to compensate accordingly. On most other cars, you also have short and long term fuel trims (STFT & LTFT), that adjust accordingly based on your conditions, and alter fuel trims accordingly (mostly CL, but OL to a smaller extent long term). They also have IAM settings, which modify timing at load sites based on historic knock and adjust slowly over time (just like autotuning, but only for timing).

As far as timing and AFR's go, all cars are different. Boxers don't dissipate heat as well, and as such are more prone to detonation than inline motors. Because of this, Subie's are traditionally run a little richer than other turbo 4's (typically around the 11.5:1 mark, many times tapering into the low 11's/high 10's), in order to use the extra fuel to cool the heads/lower cylinder temps in order to stave off detonation.

In contrast, I've seen 4G63 powered EVO's that were pretty happy around the 12.5:1 mark, and 2.3 DISI motors (also DI) that were happy anywhere from 12.5 to 11.5 depending on mods and tune. Although it's NA, my brother's GTO runs well around the 13-13.5:1 mark under full load without an issue.

My point? All cars have different preferences when it comes to AFR and timing. This is to be expected. I'm actually pretty excited about seeing what I can make this engine do, but at the same time, it is still an internal combustion engine, and as such falls under the same principles that other internal combustion gasoline engines fall under. I've played with meth, race gas, and E85 (love the corn juice!!) over the years, all of which require some form of tuning in order to reap their full benefits... but across the board, the principles stay the same. Every car is going to be slightly different, which is why I believe custom tuning is so important, but ultimately, they'll all gasoline internal combustion engines, many of which have the same parameters.

Honestly, I know you're trying to sell a product, and I respect that, I know it's a tough job, but I think you might benefit from an EFI 101 course. I think by seeing multiple platforms, and the differences between them, you might also realize just how similar the guiding principles are regardless of the variations between motors. Again, I'm not trying to come off as a prick, but I think you could learn a good bit, and expand your overall knowledge base, which would help with sales IMO.

I also think you should learn to accept the fact that timing control can be beneficial when it comes to optimizing (<--key word) a tune. It's not personal, and it's nothing against the JB3/4, so please don't take it as such, but just realize the truth of the thing. In all reality, the Procede doesn't have nearly the user adjustability as many standalone ECU's (Haltech, Motronic ect)... look at the price difference... it's not supposed to. Many people don't want/need that level of involvement. Comparatively, the JB4 is less than optimum due to the fact that it doesn't control timing... it's also only $479. You get what you pay for, and people understand that. It's been proven (even stated in my original post) that on otherwise stock cars, the DME is adaptable enough to save your motor running a JB3/4, that is well understood, and agreed upon. However, it is not optimal, as optimal IMO would be a map created specifically for a person's car, with their specific mods, on their fuel, in their environment, that does not see knock under normal conditions (i.e. consistent).

Bang for buck, you can't beat the JB3/4. This is a well known fact. However, arguing that an inferior product is somehow on the same level as it's more capable competition is a fallacy. It's cheaper... you own a good portion of the market due to price point... for the life of me I don't understand why you would argue with so many reputable tuners & knowledgeable enthusiasts who have tuned countless vehicles, when it does nothing to sway your potential customers.

Again, I am not trying to flame you, as a matter of fact, I don't think you're a bad guy, and I'm sure you're just trying to stand up for your customer base, but honestly, it's not necessary. It is what it is. The JB doesn't control timing, which is a crucial factor when tuning for optimum performance, consistency and safety. Period. It's not a bad device, it offers great bang for buck value to those who don't care (large majority), and doesn't pop motors on this vehicle. That should be enough. Either that, or if you don't like the negative stigma around having no timing control, simple answer- build a better machine. Isn't the Proboard going to have timing control? Viola.

Either way, again, not trying to be a prick. I wish you the best of luck in your endeavors, but for those of us who have tuned many different platforms, the core principles of tuning are still the same.

Just me $.02

Current- 2015 Subaru WRX

Former- E90 BMW 335xi 6MT N54 - SOLD