W3SI • View topic - You really don't need an e-manage to control timing (long)

G-ELL · **Posted:** Fri Nov 10, 2006 4:37 pm

After lots of tweaking, I think I finally understand why Matt M literally worships the ARC2. I've preached about how simple it is to setup and tune, but there are other things you can combine with it to fine tune things even more.

Before I get into that, it's amazing how much better a car will run (and how much easier it is to tune) when you don't have FPR overload issues and have the proper sized feul injector for your setups. Feul pumps as large as the supra flow so much feul and build so much pressure that the stock FPR just doesn't cut it. The effects are minor:

Moderate gas mileage (mid to lower 20's at best)
On/off LOW throttle stumble (like cruising in 1st gear thru traffic)
Extremely rich WOT conditions -> black rear bumper and exhaust tips
"Poppy idel"
"flickering" feul pressure while cruising
unable to LOWER the base fuel pressure

The car will still run and drive alright and you may not even care (this is why guy say it's not worth it to get an AFPR). There are ways to tune that out but not with just the ARC alone.

The Eric Gross feul pump rewire method is the best way for controling FPR overrun as it lowers the feul pump voltage while the ECU is in closed loop. This keep the feul pressure in check so you don't experience the above symptoms.

I know I've said before that I was never able to really tune the ARC to get the best driveablility and didn't like how "ruff" of a tune it would give in the SSG car. I'm conviced this is mainly because of the direct hotwired denso pump with the stock regulator. It even overruns my AEM FPR with the larger return hose in the white car. (go ahead and say it Adam)

Typcally what I would do is get a good rough cruising tune and idel (closed loop) with the ARC, then use the BISS screw to either richen or lean the a/f mixture at idel to get the O2s to cycle. Don't really need to do that if the FPR isn't getting overrun.

For open loop tuning (high throttle accellerating), I would just use the high knob on the ARC and lean it out or turn up the boost until I saw knock. Having NO idea what the true a/f ratio is, you'd never know how rich you're actually running and much power you're being robbed out of. Thus you'd get black tail pipes and maybe blow a little bit of black smoke out when you "get on it".

Back to the title of the thread: How to control timing. You can do this by controling the injector duty cycles while the ECU is in open loop. You have control over the IDCs with an adjustable feul pressure regulator, the feul controler, and the boost controler. So basically, all you do is set your boost, get a rough WOT tune, then use the AFPR to either fine tune the a/f ratio:

More boost = more air being counted by the MAF = less timing advance. Guys don't understand when I say it's dangerous to tune for lower boost with larger feul injectors. What you lack in air, the ECU makes up for in timing and too much timing = knock just like too much air. So if all you're going to run is 12psi, then stick with the stock turbos and feul injectors you pussy.

More feul pressure = lower IDCs as more feul is being forced thru the injector while it's open. The lower the IDCs, the MORE timing the ECU would throw out. So, if you're seeing 85% IDCs and 37 degreess timing advance, consider lowering the feul pressure to bring the IDCs up and timing down. This will allow you to run more boost or even lean out the mixture too.

You can also use feul pressure to fine tune the a/f ratio with a wideband. Raise the FP to richen, lower to lean. This gives you the "inbetween" adjustments you can't get with the broad ARC adjustments.

Now that my car runs like stock, I want to retract my statement about not being able to tune "good enough" with the ARC. Overall, I'd have to say that this is the easiest setup to tune. It sure beats luggen around a laptop and the ford MAF really helps inprove turbo spool.

A used ARC with the AEM FPR is also MUCH cheeper than buying an e-manage ultimate with all the needed sensors and crap for speed density. Then you add the cost of a laptop along with all that... I'll pass.

You really don't need an e-manage to control timing (long)

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