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Old 12-06-2006, 09:35 PM   #1
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Default Would this hurt/make power. Fuel system + AFM

I know a lot of you guys do your fuel system stuff before you do any of your turbo stuff, but from what I've read its only for a couple of weeks max...would it hurt for me to install this stuff for a couple of months? I don't have a lot of time to work on my car at home, and I wanted to do it in steps and do as much as possible before I actually went ahead w/ the turbo/dp/etc stuff put on.

Over winter break, among other projects, I'd like to install:
Walbro 190HP pump
RX-7 AFM
2001 1.8 injectors
Bipes
DIY fuel rail?
anything I'm missing? - A AFPR would NOT be a good idea right now...right?

I was curious if it'd make any more power or if it would not be good for the car.
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Old 12-06-2006, 09:50 PM   #2
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Sounds like a good idea, getting all the support hardware in place and the bugs ironed out prior to The Big Day.

I see no reason why you should not install the AFPR at this point as well. Once it's properly adjusted it should not be raising the line pressure when you're below atmospheric.

Once it's all in proper tune, these things should do no harm, though it's unlikely you'll see any power increase.


With the numerous fuel variables you're introducing (1.8 injectors, AFPR, RX-7 AFM) are you planning to invest in a wideband O2 system as well?
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Old 12-06-2006, 10:11 PM   #3
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All of those things will be fine. It's a good idea to get the injectors and AFM sorted out beforehand. The fuel pump will be fine as well...isn't like it is a 255 hp and overpumping. The Bipes will need to have the settings changed between NA and turbo, but is a great NA item as well. If it is a rough tweak with the AFM and injectors, it might be a bit off until you put the itme into tuning it.

I'm planning on doing much the same soon, actually.

BTW: start running premium fuel, and wire your fans in parallel. FM has a decent turbo prep checklist on their website...I'd read it.
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Old 12-06-2006, 10:27 PM   #4
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Those are the exact things I installed ahead of time... I also mounted my IC... no reason not to, just duct taped the ends closed.

Just for tuning and troubleshooting, I wouldn't do the RX7 afm just yet. I'd leave the stock one in. Upon getting my new manifold studs from Begi, I'm going to reinstall my turbo and put the needed 450 miles on it for the clutch break-in (lotsa driving this weekend)... then drop in the 305's and 02 clamp. When that is taken care of.... IT'S DYNO TIME! We're going to put this RX7 maf thing to the test. Granted, I'll only be running about 10psi, but the direct back-to-back comparisons on the dyno of the stock MAF vs. RX7 might convince you that for your boost level that it's not needed. No need to go through the extra work of tuning the thing. Of course it won't hurt anything to install it, just maybe extra work. Of course even if it turns out that it's worth an extra HP or two anywhere in the rev range it'll be worth it in my book. Up to you.

But back to your original question... you can install all of that stuff including the AFPR and it will affect nothing... you won't notice any difference at all. My recommendation would be however to test your fuel pump after install to make sure it'll get you the pressure you'll need eventually for the boost you plan to run. You'll need a fuel pressure gauge mounted inline (mine is before the rail)... simply clamp off the return line fully while the engine is running (careful with vice grips as they might tear the line or use something else) and note the max pressure.

Also don't forget to adjust the base fuel pressure as recommended in the Begi instructions YOU NEED TO DO THAT!!! All you do is unhook the vacuum line (allowing the AFPR to sense 0"hg) and adjust the allen bolt coming out of the top of the AFPR... I think Begi recommends that 48-50psi is a good place to start.
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Old 12-06-2006, 10:47 PM   #5
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In open loop, the car will run rich with 1.8 injectors. The ECU just isn't programmed to use them.
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Old 12-06-2006, 11:42 PM   #6
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Quote:
Originally Posted by Joe Perez View Post
Sounds like a good idea, getting all the support hardware in place and the bugs ironed out prior to The Big Day.

I see no reason why you should not install the AFPR at this point as well. Once it's properly adjusted it should not be raising the line pressure when you're below atmospheric.

Once it's all in proper tune, these things should do no harm, though it's unlikely you'll see any power increase.


With the numerous fuel variables you're introducing (1.8 injectors, AFPR, RX-7 AFM) are you planning to invest in a wideband O2 system as well?

I REALLY want to...the AEM one wideopentuning is offering looks like a pretty good deal, but I'm low on funds, and I don't know ANYTHING about widebands, other than they measure real time A/F ratios.
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Old 12-06-2006, 11:55 PM   #7
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Atlanta: I've never seen the FM check list thing...dunno how I missed it...thanks. The rich thing is what I was worried about...just hoping it wasn't TO rich...

Sam: I'm actually copying your project if you haven't noticed, I saw that you used yours for a couple of weeks, but I wasn't sure how long it would take me to get everything together, and I just need to have a solid foundation once I go turbo, and not a huge amount of issues to worry about.

Also, thanks for the tips...I'll be needing them soon
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Old 12-07-2006, 12:00 AM   #8
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I ran a RX7 AFM and 1.8L injectors for over a year N/A, no biggie. Go ahead and install all components.
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Old 12-07-2006, 12:09 AM   #9
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lol...I love that one...**** it...just do it
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Old 12-07-2006, 10:19 AM   #10
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Quote:
Originally Posted by Atlanta93LE View Post
In open loop, the car will run rich with 1.8 injectors. The ECU just isn't programmed to use them.
The fact that quite a few of us have successfully run the 1.8 injectors with zero other mods would suggest the ECU has no problem keeping up with the slighlty larger inj's.

The instant the car starts to run rich because of the bigger injectors, the ECU would read that from the 02 sensor and pull fuel. Could you see a slightly richer mix on a WB? Perhaps. Would it be enough to matter? Repeated real world results say no.

Of course there is an upper limit of how big an injector the car can handle. But someone just posted they got the car to idle with 440s... of course he did say it was spitting fuel out the tailpipe.

Brain and I and quite a few others have run the 1.8's on an otherwise completely unmodified fuel system and ECU pre turbo install... AND IT RUNS PERFECTLY!
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Old 12-07-2006, 10:21 AM   #11
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I'm idling 305s on the stock ecu and AFM it's no biggie. Took 5mins to get the correct idle mixture.
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Old 12-07-2006, 10:24 AM   #12
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Quote:
Originally Posted by Atlanta93LE View Post
In open loop, the car will run rich with 1.8 injectors. The ECU just isn't programmed to use them.
Yes, in open loop it will run slightly richer. In closed loop, the signal from the O2 sensor will keep it at Stoich. In open loop the ECU refers to the AFM signal and maps accordingly, so you will use 10% more fuel above 4000RPM unless you adjust your AFM. It probably isn't worth doing.
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Old 12-07-2006, 10:27 AM   #13
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I'm not saying the ecu can't idle them. I specifically said that "in open loop, the car will run rich." Once in open loop, the ecu doesn't know the mixture, at all. O2 sensor readings are ignored in favor of a hard-coded "fuel table". If you put in 1.8 injectors, the table is still the same as when the 1.6 injectors are in there, so essentially more fuel will be thrown in.

At least that's how they're designed

I'm planning on running my 305cc injectors a bit before going turbo, so I agree it isn't that much of a deal to run rich in open loop. Just making him aware, as he asked about what possible drawbacks there are. Not trying to discourage.

Last edited by Atlanta93LE; 12-07-2006 at 10:29 AM. Reason: addition
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Old 12-07-2006, 10:33 AM   #14
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The car is almost always in closed loop. When it's open loop, it's running rich anyways.
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Old 12-07-2006, 10:43 AM   #15
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Pre-96, I believe the car goes open loop above 4000 rpm. I dont' know about you, but I frequent that range
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Old 12-07-2006, 10:54 AM   #16
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My car doesnt go open loop after a certain rpm. It only goes open loop if I romp on it--then goes right back to closed loop.
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Old 12-07-2006, 11:03 AM   #17
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Did some more reading...looks like the 1.6L cars WOT open loop is triggered by airflow (from the AFM). On a dyno, I hear this shows up at ~4000 rpm. So, cruising above 4000 rpm will still result in closed loop.

I guess I just go WOT frequently!
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Old 12-07-2006, 11:06 AM   #18
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My na 1.6 car is sooo slow. I don't see how people can drive it that way.

Hurry up with the turbo dammit!
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Old 12-07-2006, 11:09 AM   #19
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Quote:
Originally Posted by Atlanta93LE View Post
Did some more reading...looks like the 1.6L cars WOT open loop is triggered by airflow (from the AFM). On a dyno, I hear this shows up at ~4000 rpm. So, cruising above 4000 rpm will still result in closed loop.

I guess I just go WOT frequently!
It is sort of like Wikipedia. I think you were right the first time. There is all sorts of information out there. I have found that cruising over about 4200rpm that my AFR's go richer.
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Old 12-07-2006, 11:11 AM   #20
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Quote:
Originally Posted by Atlanta93LE View Post
I'm not saying the ecu can't idle them. I specifically said that "in open loop, the car will run rich." Once in open loop, the ecu doesn't know the mixture, at all. O2 sensor readings are ignored in favor of a hard-coded "fuel table". If you put in 1.8 injectors, the table is still the same as when the 1.6 injectors are in there, so essentially more fuel will be thrown in.
At least that's how they're designed
I'm planning on running my 305cc injectors a bit before going turbo, so I agree it isn't that much of a deal to run rich in open loop. Just making him aware, as he asked about what possible drawbacks there are. Not trying to discourage.
Sorry, I read something into your post that wasn't there.

Isn't there any wiggle room with the ECU to pull fuel as it's sensing rich? I know how a map works, but will it shorten the injector pulse a little when it's sensing rich?

Also, when you install the Bipes, there's no way to keep it from pulling at least some timing... as long as it's installed, the minimum setting for it (and what you should do while still NA) is to pull a max of 4* starting at 3000rpms with an extra 1* for each 65*F of temp. Don't forget to bump it back up when you go turbo.
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