legacycentral bbs

Do we need an air fuel piggyback system like the AFC unit if we plan to run 20 plbs. of boost??? or does a fuel cut defencer allow our computer to compesate. Assuming we have done bigger injectors and a higher flowing fuel pump.


Thanks, Mike

yes, unless you want your car to run like crap. a FCD only raises the fuel cut limit, it does not alter fuel settings.

Won't the ECU still read the O2, mass airflow sensors etc. And compensate the air/fuel mixture to the desired limits? Up unto a point ofcourse.

Mark,

Do you have a bigger turbo? Intercooler? You need those first before you get anywhere near 20lbs. After that, I've tested the A/F ratios and the ecu's ability to compensate to 1.35bar today (needed to readjust the boostcontroller and "accidentally" boosted to this amount) for a second before letting off the gas. The o2 sensor was reading rich and the injectors were at 100% duty cycle. Yes, you can probably run this much but for how long? Right now I'm back at 1.15bar. Injectors are at 85% duty cycle . . . So those injectors would be next on the list . . .

Of course, if you run bigger injectors you are REQUIRED to run some sorta fuel management device (standalone or piggyback) so you can run the larger injectors properly . . .

The ecu will base the timing of the injectors on the fuel volume of the stock injectors. Once you increase the injector size, each pulse will inject more fuel causing a really crappy running engine, especially at lower rpms.

For now, I'm sure you could get 350hp out of your stock block . . . how much boost that takes is unknown to me. I still haven't dynoed my car.

I think any boost above stock it is going to run very rich to keep the engine alive. As well as pull a lot of timing. Not very good for power if you have a good IC . I want it to stay nice and rich, but the timing it pulls must be bad.

boostjunkie wrote:Do you have a bigger turbo? Intercooler?

I am in the process of ordering a VF23 and a blitz FMIC. I also am getting within a few weeks an HKS header and Perrin up and down pipes.

This is what I plan on getting for now so I can at leaste get the motor back in the car and running. Oh yeah, I forgot, I am getting the blitz electronic turbo controller thingy. Basically my initial question was...if I upgrade the injectors and the fuel pump can I get away with a piggyback fuel controller like the AFC (with the blue screen)?? or do I need to go nuts with a remapping of some sort?

Basically I dont know what to do.......so I need your help!!

As long as you change the injectors and pump, you should be fine with a S-AFC . . . our ecus are not as finicky as the wrxs and compensate pretty darn well.

BTW, let us know how your Blitz FMIC turns out. I stopped by TurboXS the other day to look at their FMICs. The guys were not sure whether the FMs would work because of how our bumpers recess as they get closer to the ground.

Is there any way to control ignition timing? Other than a whole standalone? Can our ECU be remapped to the setting we like?

Mark,

Supposedly Cobb can remap ECU's.

Also there is a japanese tech in toronto that can supposedly do the same thing. I forgot his name.....something like Yoshi.....I may be way off....

I've heard the remapping is only possible on the newer ecus.

The guy in Canada is Joshio at Japan Automotive, or something like that.

You could always try a S-ITC. Piggybacks are cool:D

The AFC is effective but only at WOT. If you plan to install it tune it in a fashion that it doesnt modify any low throttle ratios. Static maps (ignoring the oxy sensor) are used at high throttle openings.

ok, thanks for the info, and with regards to the blitz fmic, I will make it fit

The best we managed to do with the stock injectors was 318 at the wheels but we were also running a stock fuel pump and we could see the pressure drop at the high end. The car was sold before a pump was added. This was with a Garrett hybrid turbo, good intercooler, exhaust, chip, intake, rpm mod to ECU, and 104 octane gas. Ran a 13.538 sec 1/4 mile at 5200 ft alt. Supposedly this could be close to 1 sec faster at sea level.
AN(CO)
al@iwtu.net

The best we managed to do with the stock injectors was 318 at the wheels but we were also running a stock fuel pump and we could see the pressure drop at the high end. The car was sold before a pump was added. This was with a Garrett hybrid turbo, good intercooler, exhaust, chip, intake, rpm mod to ECU, and 104 octane gas. Ran a 13.538 sec 1/4 mile at 5200 ft alt. Supposedly this could be close to 1 sec faster at sea level.
AL(CO)
al@iwtu.net

What exactly is the RPM mod?