50lb injectors + stock ECU

[AceInHole]

If i said "You can theoretically upgrade to a fuel system that can handle a shizzit load of HP and a half.... for around $500", would you believe me??

Basically, between yesterday and today, talking to Asad about it, I came up with the idea that larger fuel injectors simply inject more fuel per duration of injection.  This means that larger fuel injectors are a percent larger than stock, and this percentage remains the same for the amount of air required, as a fuel/ air mixture is simply a ratio.  
So... I thought... 550cc injectors (50lb) are a bit over 2x larger than stock... and a Cobra MAF is easily a bit over 2x larger than stock (you measure air flow by velocity over area of the cross section of the pipe... the same velocity with a larger pipe would yeild a flow proportional to the area proportion), so couldn't you use a Cobra MAF with 550cc injectors, and fine tune it with an adjustable fuel pressure regulator???
Problem: different MAFs are not linearly proportional, meaning the flow percent per voltage curve between the stock 240 MAF and the Cobra MAF are not the same.  I theorized that as long as the upper curves were similar, it would work, so using fuel pressure, which is linearly proportional (thus you couldn't adjust the entire MAF curve just with fuel pressure) you could adjust the top where you need it, and be relatively safe down low.

Something clicked in my head though... the MAF unit isn't very complex itself, so couldn't you just use the stock MAF sensor, and adapt it to a larger pipe to create a larger diameter MAF using the same curve??  Theoretically, it would be almost EXACTLY proportional (neglecting the viscocity of air and drag along the pipe surface), in which case you could adjust the fuel curve using different sized pipes.

So, pricing goes:
550cc injectors - $250
Marine fuel rail stock - $30 (would have to mill it myself to adapt)
Mallory adj. FPR - $75
Walbro Fuel pump - $120
Lines and fittings - $75
----------------------
Total $550

Assuming you could source used parts, that price would drop pretty drastically.

[boosteds14]

what about the iacc valve
how is it going to idle without the computer programming the duration of the injector pulses when the iacc valve will open and close not knowing how to find the perfect idle

plus wide open throttle sensor- detects and configures the impulse of the injectors

also- even with 370cc nissan 300zx injectors u need to have it programmed by jwt

[sykikchimp]

So basically your trying to emmulate Asad's setup without the JWT? Are you using this in a temporary N/A setup?? until the turbo gets ready..

So...  If you use the larger MAF your still not increasing the Amount of air going into the intake  (or it would seem a negliable increase), and the injectors are still going to stay open for the same amount of time..  Wouldn't this still create a very Rich situation since the 50 lb/hr injectors are gonna flow twice as much fuel for the same duration of time the injector will be open?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 30 2002,4:24)</td></tr><tr><td id="QUOTE">So basically your trying to emmulate Asad's setup without the JWT? Are you using this in a temporary N/A setup?? until the turbo gets ready..

So... If you use the larger MAF your still not increasing the Amount of air going into the intake (or it would seem a negliable increase), and the injectors are still going to stay open for the same amount of time.. Wouldn't this still create a very Rich situation since the 50 lb/hr injectors are gonna flow twice as much fuel for the same duration of time the injector will be open?</td></tr></table><span id='postcolor'>
increasing the MAF size would increase the amount of air flowing in per voltage reading, so the duration of that voltage will stay the same, but more fuel and more air per voltage reading goes in.

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (boosteds14 @ April 30 2002,3:50)</td></tr><tr><td id="QUOTE">what about the iacc valve
how is it going to idle without the computer programming the duration of the injector pulses when the iacc valve will open and close not knowing how to find the perfect idle

plus wide open throttle sensor- detects and configures the impulse of the injectors

also- even with 370cc nissan 300zx injectors u need to have it programmed by jwt</td></tr></table><span id='postcolor'>
most likely it will idle like crap, mostly since larger injectors have trouble injecting small amounts of fuel anyways.

anyways, here's what the physicist had to say:
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">
the TPS doesn't "configure the impulse", the MAF does that
the IACV is a simple feedback system. if the idle is too high, it closes, if it's too low, it opens</td></tr></table><span id='postcolor'>

the setup theoretically works. &nbsp;the JWT setup simply recalibrates the fuel curve to match the MAF. &nbsp;this setup simply recalibrates the MAF to the injectors. &nbsp;any differences i might encounter with MAF sizing can be tuned using an adjustable fuel pressure regulator.

[boosteds14]

i c
i stand corrected about the tps

[AceInHole]

i'd have to check the FSM, but i'm pretty sure the TPS is only used to configure ignition timing (tip in retard and such) and possibly to give the ECU some comparison for the O2....

in any case, it's by no means a perfect setup, but it's a good $700 (ECU + MAF) that could go towards a larger turbo or something in my project for Stage II. &nbsp;I'm still only going to be using a RRFPR for the initial install. &nbsp;when i can, i'll install the said system and see if it works. &nbsp;if it doesn't, i can just get the JWT and Cobra MAF... if not, i revert back to RRFPR. &nbsp;that way, i'll have a somewhat safer fuel system to go to while shopping for a larger turbo.

[rancid240]

I dont know if this is from left field, but could an apexi AFC help any in this setup?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (rancid240 @ April 30 2002,5:19)</td></tr><tr><td id="QUOTE">I dont know if this is from left field, but could an apexi AFC help any in this setup?</td></tr></table><span id='postcolor'>
yes. &nbsp;it would help more with the Cobra MAF setup, tuning the MAF reading to the fuel curve. &nbsp;I'm trying to get around this by keeping the stock fuel curve, and adjusting the curve as a whole with MAF sizing using the stock sensor and fuel pressure.
The Apexi AFC wouldn't be as accurate as a JWT ecu though, so if i had to actually buy a fuel controller I'd probably go the JWT route.

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 01 2002,4:56)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 30 2002,4:24)</td></tr><tr><td id="QUOTE">So basically your trying to emmulate Asad's setup without the JWT? Are you using this in a temporary N/A setup?? until the turbo gets ready..

So... If you use the larger MAF your still not increasing the Amount of air going into the intake (or it would seem a negliable increase), and the injectors are still going to stay open for the same amount of time.. Wouldn't this still create a very Rich situation since the 50 lb/hr injectors are gonna flow twice as much fuel for the same duration of time the injector will be open?</td></tr></table><span id='postcolor'>
increasing the MAF size would increase the amount of air flowing in per voltage reading, so the duration of that voltage will stay the same, but more fuel and more air per voltage reading goes in.</td></tr></table><span id='postcolor'>
Sorry if this is a dumb question but the Throttle Body is only going to allow a certain amount of Air into the intake manifold without forced induction.. &nbsp;How will you not run rich if the Injector is staying open the same amount of time?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 30 2002,5:43)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 01 2002,4:56)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 30 2002,4:24)</td></tr><tr><td id="QUOTE">So basically your trying to emmulate Asad's setup without the JWT? Are you using this in a temporary N/A setup?? until the turbo gets ready..

So... If you use the larger MAF your still not increasing the Amount of air going into the intake (or it would seem a negliable increase), and the injectors are still going to stay open for the same amount of time.. Wouldn't this still create a very Rich situation since the 50 lb/hr injectors are gonna flow twice as much fuel for the same duration of time the injector will be open?</td></tr></table><span id='postcolor'>
increasing the MAF size would increase the amount of air flowing in per voltage reading, so the duration of that voltage will stay the same, but more fuel and more air per voltage reading goes in.</td></tr></table><span id='postcolor'>
Sorry if this is a dumb question but the Throttle Body is only going to allow a certain amount of Air into the intake manifold without forced induction.. How will you not run rich if the Injector is staying open the same amount of time?</td></tr></table><span id='postcolor'>
that would be correct, assuming the air is flowing at constant velocity. &nbsp;when the piping size changes, the flow velocity also changes. &nbsp;with a larger MAF, there would be more air per less flow velocity. &nbsp;the MAF sensor would read less air because it's flowing slower, and then tell the injectors to inject less fuel, not knowing that it's injecting more fuel than it thinks it is. &nbsp;the way this works, is that you're getting more air and more fuel proportionately, and keeping your air/fuel ratio intact. &nbsp;
at the throttle body, the air would assumably increase velocity, as long as it isn't reaching terminal velocity.

[sykikchimp]

thats about what I was thinkin, but it seems to me it would be very hard to get the piping the right size. &nbsp;After all, how sure are you of the correlation b/w the two sizes? &nbsp;Just b/c they are both 2x bigger doesn't mean it will move the air slow/fast enough to get the correct amount of fuel out of the injectors.

I am assuming that you would use the adjustable fuel pressure regulator to limit the amount of fuel pressure allowed to the injectors to fine tune the injectors flow rate to the aproximation of the air velocity comming through the MAF? &nbsp;In essence reducing the Flow capacity of the 550cc injectors?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ April 30 2002,7:03)</td></tr><tr><td id="QUOTE">thats about what I was thinkin, but it seems to me it would be very hard to get the piping the right size. After all, how sure are you of the correlation b/w the two sizes? Just b/c they are both 2x bigger doesn't mean it will move the air slow/fast enough to get the correct amount of fuel out of the injectors.

I am assuming that you would use the adjustable fuel pressure regulator to limit the amount of fuel pressure allowed to the injectors to fine tune the injectors flow rate to the aproximation of the air velocity comming through the MAF? In essence reducing the Flow capacity of the 550cc injectors?</td></tr></table><span id='postcolor'>
well, it could end up being the opposite.... increasing fuel pressure to inject more fuel per duration.... it will all be relative to stock.

anyways, the amount of air flowing past the MAF is what matters. &nbsp;However much air flows past the MAF will be the amount of air that flows through the throttlebody, regardless of flow velocity anywhere else in the piping. &nbsp;All that matters is that the flow through the MAF is being measured correctly.

The amount of air flowing through the MAF is AIRvelocity x AREAmaf-face. &nbsp;Increasing the area of the maf-face will increase the amount of air in a proportion of AreaModdedMAF/ AreaStockMAF. &nbsp;This has to be the same as InjectorSizeLarge/ InjectorSizeStock. &nbsp;If I can't find the exact ratio for either, I can use fuel pressure as a linear constant to increase or decrease one of those ratios, however is necessary.

The whole reason this works, is because it's using the stock MAF sensor, which will have the same velociity/ voltage curve, unlike going to a Cobra MAF sensor, and the only things I'm changing are linearly proportional.

[s15dude]

Doesn't the JWT ECU do other things as well, like adjust your timing for boost(not that you couldn't do it yourself) and reprogram your fuel maps? I could be wrong. Also, the JWT ECU is proven and really reliable is it not? So I could see spending a little over $1000 for a good fuel system( which is what I am planning on spending):
JWT ~$600
550cc injectors ~$250
Cobra MAF ~$250
Mallory adj. FPR ~$75
Walbro Fuel pump ~$120
Lines and fittings ~$75
Total ~$1325

[s15dude]

Sorry for the double post!

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (s15dude @ April 30 2002,7:35)</td></tr><tr><td id="QUOTE">Doesn't the JWT ECU do other things as well, like adjust your timing for boost(not that you couldn't do it yourself) and reprogram your fuel maps? I could be wrong. Also, the JWT ECU is proven and really reliable is it not? So I could see having a $1000 fuel system( which is what I am planning on spending):
JWT ~$600
550cc injectors ~$250
Mallory adj. FPR ~$75
Walbro Fuel pump ~$120
Lines and fittings ~$75
[B][I]Total ~$1120</td></tr></table><span id='postcolor'>
Yeah, the JWT has the advantage as far as fuel delivery and overall performance goes.
It doesn't control timing under boost, i think... not sure the stock ECU has a sensor to detect boost, although it CAN adjust timing on the overall rev range where the stock ECU doesn't normally. &nbsp;It also gets rid of tip-in retard and stuff... raises redline, takes out the speed governer (if you want), and is a 99% reliable fuel controller, compared to other ways around it.

You're missing the MAF though... the stock MAF is way out of range past around even 4 psi. &nbsp;That and 550cc injectors won't go into the stock fuel rail... and the cheapest way is to make one &nbsp;yourself from fuel rail stock.

so it's
~1120 + ~100 + ~30= $1250

[DuffMan]

The idea of regulating fuel pressure to compensate for bigger injectors is sound, and I think that has been discussed at fresh alloy before.

A few concerns I would have:

1. Are the 50lb/hr injectors electronically compatible with stock injectors? Do they have similar impedence and opperate at similar voltages? If not, it might be able to be rigged with a resistor.

2. That's almost 2x as big injectors as stock. Will the injectors be able to work properly at almost half stock pressure?

3. Will the FPR be able to work with this setup? You're going to want only about 3-4 lbs of additional fuel pressure for every 1 lb of boost. I don't know anything about that particular unit and how it works, but I am assuming it measures boost.

4. Can MAFS be moddified like that? Honestly, I have no idea.

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">The idea of regulating fuel pressure to compensate for bigger injectors is sound, and I think that has been discussed at fresh alloy before. </td></tr></table><span id='postcolor'> it's different here. &nbsp;i'm compensating by changing the area of the MAF face, not fuel pressure.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">1. Are the 50lb/hr injectors electronically compatible with stock injectors? Do they have similar impedence and opperate at similar voltages? If not, it might be able to be rigged with a resistor.</td></tr></table><span id='postcolor'> considering they can be used with the JWT setup, they should be able to run with the stock ECU. &nbsp;If not, a resistor can always be used.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">2. That's almost 2x as big injectors as stock. Will the injectors be able to work properly at almost half stock pressure?</td></tr></table><span id='postcolor'> it's actually a bit more than 2x the size of stock injectors, and yeah, they'd be really poor at 1/2 the stock fuel pressure. &nbsp;But, the whole idea is to keep fuel pressure near stock, which is why i'd have to modify the MAF.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">3. Will the FPR be able to work with this setup? You're going to want only about 3-4 lbs of additional fuel pressure for every 1 lb of boost. I don't know anything about that particular unit and how it works, but I am assuming it measures boost. </td></tr></table><span id='postcolor'>
FPR's read off of vacuum... after that it'd be the RRFPR. &nbsp;my current one is an 8:1 unit.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">4. Can MAFS be moddified like that? Honestly, I have no idea.</td></tr></table><span id='postcolor'>
the MAF is simply has a sensor that sticks into a "pipe". &nbsp;I'd have to cut it off of the stock pipe (basically cutting the MAF sensor section of the pipe off), and epoxy &nbsp;it to a larger pipe, creating a MAF with a larger face area. &nbsp;Looking at the stock MAF, it seems like a do-able thing. &nbsp;(S14 MAF's are made out of plastic.... i'm decently sure it wouldn't work in an S13 MAF, though).

[DuffMan]

Oh I C. I misread your post, I guess that's what i get for skimming.

I think the problem with using the MAFS like that would be the fact that the computer doesn't always use the MAFS to determine airflow. At WOT I think it uses a map of how much air the engine should breathe at each RPM and adds that much fuel. So with injectors about 2X as big, you'd have to boost about twice as much manifold pressure as normal to get the maps to sync up. I'm not sure exactly how much twice normal manifold pressure is (arround 10 psi of boost maybe), but I know it would change as RPMs go up. The car would run really rich at WOT at below boost RPMs (but maybe the MAFs would help you at there, not sure if the computer would use it at WOT at relatively low RPMs or not). And then would lean out at high RPMs, because the ECU is mapped out to the normal flow characteristics of the engine. This is because as the RPM's rise to really high rates, the manifold pressure of an NA engine would drop, and the amount of air getting into the engine for each RPM would drop. However with a turbo, the boost controller (i would guess a spring in this case) will keep manifold pressure constant up through the RPMs.

This would be your biggest problem I think.

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">I think the problem with using the MAFS like that would be the fact that the computer doesn't always use the MAFS to determine airflow. At WOT I think it uses a map of how much air the engine should breathe at each RPM and adds that much fuel. So with injectors about 2X as big, you'd have to boost about twice as much manifold pressure as normal to get the maps to sync up. </td></tr></table><span id='postcolor'>
it will actually depend on the MAF more than anything else. &nbsp;the O2 sensor would be more of a fine tuning/ failsafe device (which is why it can cause a CEL if unplugged like with aftermarket headers). &nbsp;also, at WOT, assumably twice as much air is flowing through while it only reads half of it, so if it's injecting by the MAF it should be fine. &nbsp;I can always check the injectors to see if they actually revert to a "full on" state at WOT with less than expected air-flow... or I can adjust the TPS so that it doesn't see WOT, in which case it would still have full on power and be injecting the proper amount of fuel, by reading the MAF. &nbsp;I'll definitely be checking everything with a shizzit and a half of diagnostics.
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">I'm not sure exactly how much twice normal manifold pressure is (arround 10 psi of boost maybe), but I know it would change as RPMs go up.</td></tr></table><span id='postcolor'> well, normal manifold pressure at WOT is 0 psi.
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">The car would run really rich at WOT at below boost RPMs (but maybe the MAFs would help you at there, not sure if the computer would use it at WOT at relatively low RPMs or not). And then would lean out at high RPMs, because the ECU is mapped out to the normal flow characteristics of the engine.</td></tr></table><span id='postcolor'> &nbsp;this is still assuming the engine completely disregards the MAF. &nbsp;even then, the prior fix would work here. &nbsp;also, as i said, it should really be flowing twice what it reads....
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE"> This is because as the RPM's rise to really high rates, the manifold pressure of an NA engine would drop, and the amount of air getting into the engine for each RPM would drop. However with a turbo, the boost controller (i would guess a spring in this case) will keep manifold pressure constant up through the RPMs. </td></tr></table><span id='postcolor'> rising rate fuel pressure regulator would take over and hopefully prevent a lean situation during a boost situation. &nbsp;this should keep the fuel system boost sensitive.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">This would be your biggest problem I think.</td></tr></table><span id='postcolor'> only if the injectors revert to a "full-on" state, in which case i just manually set the TPS to never read full-on. &nbsp;really, i could get past the tip-in retard doing this, but i'm almost positive the MAF is used to create the fuel map. &nbsp;i can always check it by clogging the intake enough to restrict airflow, and see if my A/F gauge reads past rich.

[s15dude]

Good luck if you try this, what other componets are you gonna use(turbo size, manifold, intercooler)?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (s15dude @ May 01 2002,02:53)</td></tr><tr><td id="QUOTE">Good luck if you try this, what other componets are you gonna use(turbo size, manifold, intercooler)?</td></tr></table><span id='postcolor'>
well, i probably won't try it untill i have the turbo components in and have been running off the RRFPR for a while.... but the turbo is a Volvo TD05, manifold is custom made log style, and intercooler is off a 1g eclipse.

[sykikchimp]

So your going to (possibly) install and run the Larger MAF with stock sensor, 550cc injectors, RRFPR, and fuel pump on your N/A application? &nbsp;(I know you plan to turbo..)

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,1:28)</td></tr><tr><td id="QUOTE">So your going to (possibly) install and run the Larger MAF with stock sensor, 550cc injectors, RRFPR, and fuel pump on your N/A application? (I know you plan to turbo..)</td></tr></table><span id='postcolor'>
it would be relatively safer to run it N/A and see if it works there. &nbsp;I've got the A/F meter already, so I'd have a basic input on how it handles the lower curve. &nbsp;From there, it would be raising boost lb by lb to see if the air/fuel mixture stays stoich. &nbsp;The biggest problem as I see it would be some irregularity with however i re-design the MAF, possibly reaching some point where some slight turbulence throws off the reading.

The thing is... i already have the fuel system to handle the initial part of the turbo project (RRFPR) and I have the turbo, and a manifold coming in, so i'll probably stick to the ~$1000 turbo project before i attempt the new MAF idea.

[sykikchimp]

What are you thinkin about making the MAF out of? PVC pipe? That would seem the best way to spec out the appropriate size.. then once you get the best diamater you could get a cutome intake peice made to connect to the turbo with a hole cut in it made to accept the MAF sensor..

Also would you use the RRFPR with this fuel system?

side question.. &nbsp;Would adding a top feed fuel rail for the 550cc's decrease Hood Clearance ? (Trying to figure out if my STB would fit over a top feed.. &nbsp;Not sure what the difference is b/w a side feed and top feed either. &nbsp;I've never seen them side by side. &nbsp;(and who makes 550cc injectors that fit the KA? &nbsp;assuming they are some engines OEM injectors?)

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,1:40)</td></tr><tr><td id="QUOTE">What are you thinkin about making the MAF out of? PVC pipe? That would seem the best way to spec out the appropriate size.. then once you get the best diamater you could get a cutome intake peice made to connect to the turbo with a hole cut in it made to accept the MAF sensor..</td></tr></table><span id='postcolor'>
PVC seems to be the best bet. &nbsp;Once i have the MAF sized though, i can just adapt it to the intake, instead of vice versa. &nbsp;I'd bet that if it was an actual part of the intake, it might be a bit more accurate though.

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,1:45)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,1:40)</td></tr><tr><td id="QUOTE">What are you thinkin about making the MAF out of? PVC pipe? That would seem the best way to spec out the appropriate size.. then once you get the best diamater you could get a cutome intake peice made to connect to the turbo with a hole cut in it made to accept the MAF sensor..</td></tr></table><span id='postcolor'>
PVC seems to be the best bet. Once i have the MAF sized though, i can just adapt it to the intake, instead of vice versa. I'd bet that if it was an actual part of the intake, it might be a bit more accurate though.</td></tr></table><span id='postcolor'>
Thats what I was thinkin'.. &nbsp;makin it part of the intake would lower turbulence. &nbsp;Accuracy is key. &nbsp;You would still be running stock fuel maps which really aren't optimized for performance.. &nbsp;Would you get an aftermarket fuel map processor like S-AFC?

--(SO many questions..)--

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,1:55)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,1:45)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,1:40)</td></tr><tr><td id="QUOTE">What are you thinkin about making the MAF out of? PVC pipe? That would seem the best way to spec out the appropriate size.. then once you get the best diamater you could get a cutome intake peice made to connect to the turbo with a hole cut in it made to accept the MAF sensor..</td></tr></table><span id='postcolor'>
PVC seems to be the best bet. Once i have the MAF sized though, i can just adapt it to the intake, instead of vice versa. I'd bet that if it was an actual part of the intake, it might be a bit more accurate though.</td></tr></table><span id='postcolor'>
Thats what I was thinkin'.. makin it part of the intake would lower turbulence. Accuracy is key. You would still be running stock fuel maps which really aren't optimized for performance.. Would you get an aftermarket fuel map processor like S-AFC?

--(SO many questions..)--</td></tr></table><span id='postcolor'>
i could always fine tune the fuel MAP as a whole by adjusting fuel pressure. &nbsp;the real point of this is to make a simple and easy to use system that costs less and works just as well. &nbsp;buying an S-AFC i could just go to a Cobra MAF and do dyno time.... but that's $$ and complexity.

[sykikchimp]

Wht is the difference in Fuel pressure required for to flow 270cc through stock, and 550cc through the new ones? &nbsp;Would you have to buy an aftermarket fuel pump to increase fuel pressure? &nbsp;(maybe I'm just unsure about how the whole Adjustable Fuel pressure mechanism)


also.. &nbsp;questions I added with edit earlier..

---Also would you use the RRFPR with this fuel system?

side question.. &nbsp;Would adding a top feed fuel rail for the 550cc's decrease Hood Clearance ? (Trying to figure out if my STB would fit over a top feed.. &nbsp;Not sure what the difference is b/w a side feed and top feed either. &nbsp;I've never seen them side by side. &nbsp;(and who makes 550cc injectors that fit the KA? &nbsp;assuming they are some engines OEM injectors?)

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,2:11)</td></tr><tr><td id="QUOTE">Wht is the difference in Fuel pressure required for to flow 270cc through stock, and 550cc through the new ones? Would you have to buy an aftermarket fuel pump to increase fuel pressure? (maybe I'm just unsure about how the whole Adjustable Fuel pressure mechanism)


also.. questions I added with edit earlier..

---Also would you use the RRFPR with this fuel system?

side question.. Would adding a top feed fuel rail for the 550cc's decrease Hood Clearance ? (Trying to figure out if my STB would fit over a top feed.. Not sure what the difference is b/w a side feed and top feed either. I've never seen them side by side. (and who makes 550cc injectors that fit the KA? assuming they are some engines OEM injectors?)</td></tr></table><span id='postcolor'>
the fuel pressure required should be the same, and i'd need a new fuel pump to actually be able to keep fuel pressure, as more fuel is being dumped and thus more fuel needs to be pumped. &nbsp;the adjustable fuel pressure would just be a fine tuning device.

with this system, i don't think i'd need the RRFPR. &nbsp;It might come in handy if i decide to boost something like 20+ psi, but that won't happen anytime soon.

i'm not sure about the hood clearance but i'm pretty sure you won't have any problems with a top feed fuel rail and a STB. &nbsp;

the whole reason i'd need a fuel rail is because 50lb injectors aren't made for the KA fuel rail. &nbsp;I think Apexi units might, or any aftermarket injectors made to fit into the stock rail for the SR..... since the SR injectors fit the KA IIRC.

[sykikchimp]

ok.. just to clear this up in my head..

The Adjustable Fuel pressure regulator would allow you to decrease/increase the amount of fuel that could get through the injectors for a any given momment that they are open?

And how would you judge the adjustments effectiveness? with the A/F gauge? &nbsp;If it shows rich, decrease fuel pressure slightly? and vice versa for lean?

How dangerous for you engine is to have all this experimental fuel management in there? &nbsp;say you run way lean when you start it up.. &nbsp;could you cause detonation at idle?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,2:30)</td></tr><tr><td id="QUOTE">ok.. just to clear this up in my head..

The Adjustable Fuel pressure regulator would allow you to decrease/increase the amount of fuel that could get through the injectors for a any given momment that they are open?

And how would you judge the adjustments effectiveness? with the A/F gauge? If it shows rich, decrease fuel pressure slightly? and vice versa for lean?

How dangerous for you engine is to have all this experimental fuel management in there? say you run way lean when you start it up.. could you cause detonation at idle?</td></tr></table><span id='postcolor'>
adjusting fuel pressure would affect the entire fuel curve... so it would increase or decrease the amount of fuel flowing through the injectors throughout their range of injection.

i'd most likely judge the effectiveness with the old "seat of the pants" dyno in combination with the A/F meter and just plain how the engine sounds and feels.

Danger?? &nbsp;It wouldn't be as dangerous through the lower part of the curve... i highly doubt i'm going to kill my engine at idle (if that's even possible). &nbsp;It would probably be the same as if my fuel pump disconnected or an injector clogged and i ran lean at some lower RPMs. &nbsp;Throughout the failsafe range (like when the ECU gives a check engine light and cuts the engine to only 3500 rpms) I think i'd be pretty safe.

Stuff like this is apparently done in Mustangs all the time, matching MAF's with injectors.

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,2:36)</td></tr><tr><td id="QUOTE">adjusting fuel pressure would affect the entire fuel curve... so it would increase or decrease the amount of fuel flowing through the injectors throughout their range of injection.</td></tr></table><span id='postcolor'>
could you actually increase fuel pressure with the adjustable fuel pressure mechanism? &nbsp;Or will it only decrease the flow rate of the fuel?

I guess to simplify, Does it work like a faucet to a Garden hose? &nbsp;Or can it raise the fuel pressure above stock level?

Like I said, I'm not to sure how the adjustable Fuel regulators work. &nbsp;Do they go in the Fuel return line? or Feed line?

(what I really need is a sorce that explains how RRFPR's, and AFPR really work exactly)

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 01 2002,10:47)</td></tr><tr><td id="QUOTE">well, normal manifold pressure at WOT is 0 psi.</td></tr></table><span id='postcolor'>
0 psi would mean there is no air in the manifold. Manifold pressure (absolute pressure) is always going to be somewhere between 1 atm and 0 on a NA car, but it will decrease as the engine reaches it's volumetric efficiency. As RPM's rise the amount of air the engine can take in per revolution will decrease, and manifold pressure will decrease. The ECU has maps based on the engine's flow characteristics and different RPM's.

With a turbo, the engine is being force fed air, and manifold pressure will stay constant at 1atm + boost when under maximum boost. This will no not line up well with the fuel maps the engine has in it now.

My understanding of MAFS is that they are not perfect, especially when flowing higher levels of air. At WOT your car is going to breathe in the same amount of air at x rpm (negating altitude considerations). So the data from the MAFS is only used to confirm that the car is breathing at max volumetric efficiency, and the actual amount of fuel is determined based on the fuel maps.

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,4:39)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,2:36)</td></tr><tr><td id="QUOTE">adjusting fuel pressure would affect the entire fuel curve... so it would increase or decrease the amount of fuel flowing through the injectors throughout their range of injection.</td></tr></table><span id='postcolor'>
could you actually increase fuel pressure with the adjustable fuel pressure mechanism? Or will it only decrease the flow rate of the fuel?

I guess to simplify, Does it work like a faucet to a Garden hose? Or can it raise the fuel pressure above stock level?

Like I said, I'm not to sure how the adjustable Fuel regulators work. Do they go in the Fuel return line? or Feed line?

(what I really need is a sorce that explains how RRFPR's, and AFPR really work exactly)</td></tr></table><span id='postcolor'>
the chain is like this:

fuel pump
&nbsp; |
fuel line
&nbsp; &nbsp;|
injectors
&nbsp; |
fuel pressure regulator
&nbsp; |
return line

so yes, it's like a garden hose, but think of the fuel pump as the faucet, the fuel rail as the hose, and the FPR as the end of the hose. &nbsp;as you close the end of the hose, pressure builds up inside the hose. &nbsp;water that gets out would be like fuel going through the return line.

an RRFPR is like a regular FPR. &nbsp;a regular FPR "opens" and therefore releases pressure when there's more vacuum. &nbsp;as the throttle body opens, vacuum decreases, and the FPR "closes". &nbsp;at WOT, there is no vacuum, and the FPR would be at "full closed" or something near that. &nbsp;an RRFPR works on the other end... under vacuum and zero pressure it's "open", but as it senses boost it "closes" and creates more pressure in the fuel lines. &nbsp;

now, the injectors feed off of the fuel rail which is under pressure since the FPR is creating pressure in the lines and rail between the FPR and the fuel pump. &nbsp;raising pressure would cause the injectors to inject more fuel, just as raising pressure in a hose (turning the faucet more "on") would result in more water flowing through the hose, and being "injected".

hope that worked.

[sykikchimp]

Thats interesting.. &nbsp;But if it used the MAF's only to Verify Volume, and supplied fuel based on hard hard your hitting the gas, what sensor is telling it how much gas is applied? &nbsp;I thought the accelerator pedal was just pulling cable to rotate the Butterfly on the intake to allow the engine to consume more air.

[DuffMan]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 02 2002,3:48)</td></tr><tr><td id="QUOTE">Thats interesting.. &nbsp;But if it used the MAF's only to Verify Volume, and supplied fuel based on hard hard your hitting the gas, what sensor is telling it how much gas is applied? &nbsp;I thought the accelerator pedal was just pulling cable to rotate the Butterfly on the intake to allow the engine to consume more air.</td></tr></table><span id='postcolor'>
<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/confused.gif" border="0" valign="absmiddle" alt='???'>

The amount of time the injector is open determines how much gas is applied.

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,4:47)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,4:39)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,2:36)</td></tr><tr><td id="QUOTE">adjusting fuel pressure would affect the entire fuel curve... so it would increase or decrease the amount of fuel flowing through the injectors throughout their range of injection.</td></tr></table><span id='postcolor'>
could you actually increase fuel pressure with the adjustable fuel pressure mechanism? Or will it only decrease the flow rate of the fuel?

I guess to simplify, Does it work like a faucet to a Garden hose? Or can it raise the fuel pressure above stock level?

Like I said, I'm not to sure how the adjustable Fuel regulators work. Do they go in the Fuel return line? or Feed line?

(what I really need is a sorce that explains how RRFPR's, and AFPR really work exactly)</td></tr></table><span id='postcolor'>
the chain is like this:

fuel pump
|
fuel line
|
injectors
|
fuel pressure regulator
|
return line

so yes, it's like a garden hose, but think of the fuel pump as the faucet, the fuel rail as the hose, and the FPR as the end of the hose. as you close the end of the hose, pressure builds up inside the hose. water that gets out would be like fuel going through the return line.

an RRFPR is like a regular FPR. a regular FPR "opens" and therefore releases pressure when there's more vacuum. as the throttle body opens, vacuum decreases, and the FPR "closes". at WOT, there is no vacuum, and the FPR would be at "full closed" or something near that. an RRFPR works on the other end... under vacuum and zero pressure it's "open", but as it senses boost it "closes" and creates more pressure in the fuel lines.

now, the injectors feed off of the fuel rail which is under pressure since the FPR is creating pressure in the lines and rail between the FPR and the fuel pump. raising pressure would cause the injectors to inject more fuel, just as raising pressure in a hose (turning the faucet more "on") would result in more water flowing through the hose, and being "injected".

hope that worked.</td></tr></table><span id='postcolor'>
thanks that helped... but... &nbsp;where does the Adjustable fuel regulator go?
I understand this is stock:

fuel pump
&nbsp; |
fuel line
&nbsp; &nbsp;|
injectors
&nbsp; |
fuel pressure regulator
&nbsp; |
return line

Is this where would the RRFPR go? here?:

fuel pump
&nbsp; |
fuel line
&nbsp; &nbsp;|
injectors
&nbsp; |
fuel pressure regulator
&nbsp; |
RRFPR
&nbsp; |
return line

How about the Adjustable Fuel pressure regulator? &nbsp;I would assume here:

fuel pump
&nbsp; |
fuel line
&nbsp; &nbsp;|
injectors
&nbsp; |
fuel pressure regulator
&nbsp; |
Adjustable Fuel Pressure Regulator
&nbsp; |
return line

If those assumptions are correrct, how would you use the AFPR, and RRFPR in conjunction?

[AceInHole]

adjustable fuel pressure regulator would replace the stock fuel pressure regulator. &nbsp;using both in conjunction would be like the RRFPR on stock setup, with the stock regulator replaced with the adjustable one.

also, the MAF doesn't measure volume, it measures speed. &nbsp;since airflow is cross sectional area times velocity, changing the cross section will yeild more or less airflow per MAF reading, since at similar velocities, different sized MAFs will read the same, but have different airflows.

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,6:40)</td></tr><tr><td id="QUOTE">adjustable fuel pressure regulator would replace the stock fuel pressure regulator. using both in conjunction would be like the RRFPR on stock setup, with the stock regulator replaced with the adjustable one.

also, the MAF doesn't measure volume, it measures speed. since airflow is cross sectional area times velocity, changing the cross section will yeild more or less airflow per MAF reading, since at similar velocities, different sized MAFs will read the same, but have different airflows.</td></tr></table><span id='postcolor'>
And different voltages correct?

[Jeff240sx]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 02 2002,3:11)</td></tr><tr><td id="QUOTE">(and who makes 550cc injectors that fit the KA? assuming they are some engines OEM injectors?)</td></tr></table><span id='postcolor'>
Any 550cc injector that fits in a SR motor will be a direct drop-in replacement for a KA. &nbsp;DOHC.
They are side feed, and so is the SR. &nbsp;This is established.
Srswap.com has SARD 550cc injectors for the Sr, and I have emailed Yury a few times to determine the fitting of those injectors.
He said they WILL drop into the fuel rail for a DOHC, but the electrical harness won't work. &nbsp;Thats why all SARD injectors come with their own harness that has to be SOLDERED into our stock harness.
Hope that helped.
-Jeff

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (Jeff240sx @ May 02 2002,8:59)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 02 2002,3:11)</td></tr><tr><td id="QUOTE">(and who makes 550cc injectors that fit the KA? assuming they are some engines OEM injectors?)</td></tr></table><span id='postcolor'>
Any 550cc injector that fits in a SR motor will be a direct drop-in replacement for a KA. DOHC.
They are side feed, and so is the SR. This is established.
Srswap.com has SARD 550cc injectors for the Sr, and I have emailed Yury a few times to determine the fitting of those injectors.
He said they WILL drop into the fuel rail for a DOHC, but the electrical harness won't work. Thats why all SARD injectors come with their own harness that has to be SOLDERED into our stock harness.
Hope that helped.
-Jeff</td></tr></table><span id='postcolor'>
Are there any that don't require modification of the harness?

[AceInHole]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (sykikchimp @ May 01 2002,8:02)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (AceInHole @ May 02 2002,6:40)</td></tr><tr><td id="QUOTE">adjustable fuel pressure regulator would replace the stock fuel pressure regulator. using both in conjunction would be like the RRFPR on stock setup, with the stock regulator replaced with the adjustable one.

also, the MAF doesn't measure volume, it measures speed. since airflow is cross sectional area times velocity, changing the cross section will yeild more or less airflow per MAF reading, since at similar velocities, different sized MAFs will read the same, but have different airflows.</td></tr></table><span id='postcolor'>
And different voltages correct?</td></tr></table><span id='postcolor'>
basically, the same velocity produces the same voltage, but different airflows.

similar airflows will produce proportionally different velocities