ECU Tune Stage 2

[gest24]

Besides the Z32 MAF what else is needed to make the Stage 2 chip worth it, short of throwing NOS or a turbo on.

[shotgunslade]

Probably cams, plus exhaust, plus intake mods, (filter, maybe snorkus replacement). All of those working together would increase airflow beyond the range of the OEM MAF, based on Mychailo's monitored results, especially with a 5MT allowing higher shift points.

[gest24]

Exhaust and Intake are in the plans. Where do we get cams at?

[mbtoloczko]

Exhaust and Intake are in the plans. Where do we get cams at?

You can get the cams from Delta Cam (http://www.deltacam.com/), or from TomsSVX. I think TomsSVX is getting a deal from Delta Cam. You might want to hold off a few weeks on ordering though. I'm working with Delta Cam to come up with a better intake cam profile. I'll have more info in about a week.

[gest24]

First lowering springs, now cams... you're a one stop shop... uh shop.

[AppStateSVX]

Stage 2 is a MUST have to reach over 250 hp, the MAF will max out unless you get it. I think the SVX's potential is finally going to be realized now.

[Earthworm]

What about a manual transmission? :)

[gest24]

I've read about some guys installing an Impreza FPR in their SVX. Would this also help augment the Stage 2 chip?

[shotgunslade]

Need to be careful with increased fuel pressure with the Stage 2 chip. Can lead to idle hunting problems. Stage 2 v 4 was set up too rich at idle, and users experienced hunting idle and stalling. In putting an adjustable FPR on my car, Tom Johnson initially set the fuel pressure at higher than stock, and experienced a similar idle instability. So, I think I will keep it at stock pressure normally for convenience, but maybe raise it when I really want optimal engine performance at high revs. A long way of saying that the adjustable fpr may be a better choice than the Impreze fpr.

[SVXRide]

According to the ECUTune web site, the 2v5 chip works fine with the Imprezza fpr....
-Bill

[shotgunslade]

After we have reset my fpr to stock pressure, we'll know if that statement is correct, depending on what happens to the idle stability.

[TomsSVX]

Dropping the pressure from 42 psi w/o vaccum the idle to 37 the idle was restored and strange hunting stopped. I would still like to drop it a little more to see if it would help the stalling problem that comes with the 5 speed install. Anyway, I would highly suggest using an adjustable FPR rather than the imprezza.

Tom

[mbtoloczko]

Dropping the pressure from 42 psi w/o vaccum the idle to 37 the idle was restored and strange hunting stopped. I would still like to drop it a little more to see if it would help the stalling problem that comes with the 5 speed install. Anyway, I would highly suggest using an adjustable FPR rather than the imprezza.

Tom

I thought that LAN said in one of his posts that the stage 2v5 was tuned for 42 psi. I guess not?

[TomsSVX]

Thats what I thought as well but the car runs great at ~37psi. I may try to bump it to 40 to see if we can egt away with that.

Tom

[gest24]

Where can I find one of these adjustable FPR?

[TomsSVX]

They are all over ebay

Tom

[gest24]

Looked at Ebay, there are tons of FPRs... which one is the better/best one?

[TomsSVX]

well that is more personal taste at this point, it is simple a pressure regulator that can restrict flow going back to the fuel tank on the return line. With this pinch it will increase fuel pressure on the incomming line to make up for it. So in reality, any regulator will work but which gauge is the most accurate is now a concern

Tom

[gest24]

What threw me off was the labeling of the FPRs for diff. kinds of cars.

[Jade Dragon]

An idea im drawing up for inclreasing airflow. is to take the intake and split it into to individual intakes. Run one to each side of the car. It would require remote mounting the battery and doing a little triming, but it would douple the possible airflow.:D

[shotgunslade]

As I understand it, the ECU controls the idle fuel delivery in open loop mode, in that it doesn't receive O2 sensor information to adjust the fuel injector pulse width. The ECU normally receives inputs for rpm, throttle position, air flow through the MAF, some temperatures, O2, and a few other things. Does it receive inputs on fuel pressure? If not, can it really adjust to higher fuel pressure when it is in open loop operation mode, as it is when the engine is idling?

[TomsSVX]

No it cannot sense fuel pressure. But when the AFR gets too rich the engine will compensate for it

Tom

[mbtoloczko]

Up to 20-25% throttle position (never took the time to determine the exact value), the ECU controls the motor in closed-loop using O2 sensor data to do its best to maintain a 14.7:1 afr. At idle, its difficult for the ECU to control the afr precisely though because at idle the volume of exhaust gas passing the O2 sensors is small, and it takes a while for the O2 sensor to sample enough gas for its output value to change. And if the fuel pressure is too high, the ECU might not be able to compensate the injector enough to bring the afr into range.

In open-loop, the O2 sensor data are not used, and more fuel pressure means richer afr. The increase in fuel goes roughly as the square root of the fuel pressure.

[gest24]

I've been getting ready to start ordering parts for my SVX. I want to get the stage 2 but really can't swing $700 for the full set up. So could I get the chip and not buy the Z32 MAF and just source one on Ebay at a later date.:confused:

[TomsSVX]

yes, but in this case. You need to wait until you gte the MAF to install it. I figured you knew that but just being safe

Tom