The other end of the hose attaches to this hose, which is connected to the maf at one end and to the blower inlet via a 3.5" rubber coupling from Home Depot (which you can see in the pic above):

.[/QUOTE]

This piece is an oem Z32 intake duct part.[/QUOTE]

Im tryin to understand all of this[/QUOTE]




Pictures have been edited to include some explanatory text.

 

you need a recir system even when you put your Z32-MAF in the stock spot ??

-matt

 

No.....you don't.

I would seriously consider if you do put it on the charged side however that you keep a socket wrench and a spare MAF in your trunk, just in case it blows.

IanS

 

Well I havent really decided where I am going to put it yet....really up in the air and Ill wait till either more people put in the fender well or on the charged side

-matt

 

I'll be helping Ian on this...I don't think that there will be too much of a problem drawing up a diagram. I'm thinking of maybe even doing a CAD drawing...but we'll see.

S

 

You can get home in limp mode if the maf blows, from what I've heard. But I do keep a spare in the trunk anyway.

 

Stephen,

You think your lean AFR and intermittent light throttle detonation could be a result of JWTs program not accounting for the extra air you're flowing from these "improvements" you've made?

I think you're flowing sufficiently more air then JWT has accounted for and that's why you're having some issues including your lean AFR, which isn't normal. Maybe a reprogram to correct for more airflow would be a good idea.

Just a thought to account for all these optimizations you've made.

 

You can gain power running an IC with a SC, it's just difficult.

Aquamist is simple to install and if AFR and/or timing is tuned more aggressively, you will gain power.

BOTH are great at decreasing charge temps, which drastically decreases the potential for detonation. However, only Aquamists' in-cylinder cooling of the valves, head surface, cylinder walls, piston surface, and especially the plug tip/carbon deposits allows a safer stable combustion process with minimal chance for preignition.

Fuel ratios of <12.5:1 to combat detonation are inefficient and decrease power. It takes 1/6 the amount of water to combat detonation compared to fuel due to it's 6x latent heat(gas = 350 vs. water = 2256). Water alone will allow you to SAFELY increase AFR, which allows more air into the combustion process along with all it's cooling benefits to produce *MORE* power. Add in upto 50% methanol to the mix and you have even greater knock suppression then water alone.

 

It seems however that if I go above 13.0:1 I lose power. Everything i've read about AFR in outside articles/reports tells me this also is true. That's why I gained power by adding more fuel in the dynos above.

It seems somewhere between 12.5:1 and 13:1 is the "sweet spot" for AFR. Anyone have conclusive data on this? I know some people gained hp before by dropping it from 12.5:1 to 11.5:1. (I think it was Kev, but I'm not 100% on that). What does that tell us? What does it mean?

Granted - the JWT seems to be keeping me about at 12.0:1 - which is a little too low if I were IC'ed or had Aquamist and wanted to "lean it out".

So, assuming leaning it to say 13:1 added power, How would that be done? With an adjustable FPR? (This is of course AFTER the Aquamist goes in).

IanS

 

I'm still researching/learning how tuning with WI/WAI is performed.

I've only just scratched the surface, but here is one place I think has the answers, but I'm still digging through:
http://waterinjection.info/phpBB2/

 

Just to clarify, I'm far from an expert on tuning, let alone Aquamist tuning, so take this for what it's worth.

Timing is typically directly related to injector pulse-width, so leaner(less pulse-width) means less timing advace = less power and richer = vise versa. Also, sometimes when you see a dip in AFR, it's because the MAF is measuring more air and the ECU is richening the AFR, so more air is causing more power not necessarily the excess fuel(ignoring added timing).

I'd have JWT reprogram your ECU, so you keep your timing. Otherwise, it's AFC or play with fuel pressure.

Also, JWT programs Aquamist for the SR20 guys by having a daughter board that turns on the Aquamist, advances the timing, and plays with the fuel.

 

The way I understand it is that since the fuel mapping is based on maf input, any mods that improve air flow are automatically accounted for already. Thats the beauty of going to an air-flow referenced engine management system. The ecu is pretty much blind to mods, all it sees is voltage from the maf, TPS signal and engine rpm.

What I am wondering about, though, is my TPS signal. My TPS has always sent a somewhat low signal. (The SAFC monitors TPS voltage, so I know what I'm getting at different throttle settings.) For instance, the FSM says that TPS voltage should be approximately (the FSM's wording) .36V at idle and 4V at WOT. My signals are around .2V at idle and 3.6V at WOT. It could be that the ecu is interpreting the 3.6V as something less than WOT and therefore thnks the engine is not being loaded 100%, hence it is not giving full mixture enrichment.

I have tried adjusting my TPS to give me 4V at WOT, but when I do I get an idle speed of around 2000 rpm that won't come down, even when I follow the FSM's procedure for idle adjustment.

What I am going to do as an experiment is this. Since I am using a Cartech FMU to fiddle with afr and the SAFC is lying unused, I am going to route the TPS signal through the SAFC so that I can increase or decrease the TPS voltage going to the ecu. That way I can artificially adjust the TPS voltage to give me 4V at WOT above a certain rpm. Then do some runs and see where my afr is.

 

I agree. However, with the larger injectors and the Z32 MAF, JWT had to rebuild the closed and open loop maps. I don't claim to know how they exactly acheive this, but I'd suspect that they were built based on X-cfm of airflow at X-rpm and X-load with a standard SC kit. You have a Pathfinder TB, matched IM, 3" crossover piping, CAI, and Z32 elbow, correct? I'd ASSume with all your changes you've considerably helped increase airflow and JWTs not accounting for this in their program especially under partial throttle/light loads.

I've always heard/considered JWT to be ultra-conservative, but maybe in this case they're a little to agressive on the partial throttle/light load map locations. Just something you might ask JWT about. I'm sure they'd help defunk this.

Hmnnnn....I'm going to think about this. I don't think that could be the problem, but worth a shot I guess.

 

One other suspect I'll always have in the back of my mind is those olive injectors and whether they're really 370cc. Even if they are, I've read that non flow-matched injectors can cause detonation issues when one lower cc flowing injector happens to be located on a cylinder that gets less fuel then it needs and you must retard ALL cylinders for that detonation prone one. Basically, you're limiting all cylinders by your weakest.

Just trying to think of anything.

 

I only had the olive injectors in for about two weeks. When I got the partial throttle detonation I jumped to the conclusion that it was the injectors, so I bought brand new (purple) ones from the dealer. But that was not the problem. The olive ones had been flow matched by RC Engineering, according to the documentation that came with them.

 

JOo must tell me these things, so I don't get confused...LOL!

How much?

 

So, as soon as you put in the Z32 MAF, TT injectors, and JWT ECU or close there after, you got some light throttle detonation, correct?

Any other changes you can think of?

 

If the air moves past the MAF is is accounted for at any trottle position/rpm range.

 

That's right, but I only get it on very warm days after the engine is hot. It happens when accelerating at about 40-50% throttle, and injector duty cycle is 10-20%. I helped the situation considerably when I recently got a Cartech fmu and set it so that it raises fuel pressure just before the onset of boost (like at about 3" vacuum).

Like I mentioned earlier I feel that it may be a timing issue caused by my TPS sending a lower than expected voltage to the ecu. Timing maps are controlled by rpm and TPS voltage (and maybe maf volts, too), so perhaps a low TPS voltage is making the ecu think the engine is not being loaded as heavily as it really is under partial throttle acceleration, and timing may be advanced too far for the conditions to warrant.

What I'm going to do this weekend is block off the IAC air supply and use the throttle stop set screw (the one that controls the butterfly position at rest, not the plastic screw up by the IACS) to control idle speed. Then I can set the TPS to give me 4V at WOT without having a 2000 rpm idle. This may or may not work. Certainly the engine won't idle very well until it is warmed up, but now that the weather is warm that won't be much of a problem. But I also lose idle speed adjustment for when the AC is on or when the power steering pump is being used, so I don't consider this a fix, just an experiment. If it does work, I can find out if the higher voltage TPS setting eliminates the partial throttle pinging.

DAVEB got me six injectors at $102 apiece, slightly better than what Courtesy sells them for.

 

JRNissan has them for $91 a piece till May

-matt

 

Sounds like the map is too lean at those particular load/RPM points. Has your LM-1 been able to capture AFR during any of those episodes?

Yes, MAF will measure additional incoming air, but how much fuel/timing JWT plugged into the two 3D maps at those particular locations may be too agressive for your SC setup pulley size and lower restriction vs. a standard SC kit or maybe your intake temps are just too high and you could benefit from an IC or WI. Of course, forcing in extra fuel with your Cartech to go from 12:1-->11.5:1 will work too.

Not sure about 4th vs. 5th gen ECU, but 5th gens timing maps are Injector Pulse Width x RPM. Pulse width is determined from loadxRPM. As far as I can tell, load is a combination of TPS, MAF voltage, and a bunch of other stuff all calculated together, but mostly MAF voltage.

Sounds like a plan to eliminate another possibility. Eventually, we'll get there. However, I still suspect if this wasn't an issue before, then it's Z32 MAF/injectors and JWT ECU related.

Did you sell the olive green ones? If not, are you?

 

So - yesterday an EEPROM from a 1996 JWT ECU with 370's/Z32 MAF and SC Program showed up along with a Z32 MAF from Confused.

I remembered after he shipped it that my ECU is actually a 1995. But decided that logically if a 1995 AND 1996 JWT ECU works fine in a 97 Maxima, the EEPROM should work.

Put the Z32 MAF in (on the charged side until I figure out piping) and the EEPROM.

Started the car - it ran SUPER rich, and the MAF was reading 3.7 volts at idle, where my A32 MAF usually reads around 1 volt.

So obviously either the MAF is bad (unlikely) or the 96 EEPROM doesn't work in a 95 ECU. This doesn't make a whole lot of sense to me.

Anyone care to try an explanation for this?

I put the A32 MAF and EEPROM back in and it runs fine again.

 

The maf is probably reading high because its on charged side.

 

Nope - can't be it - JWT's ECU Programs are generic (they don't have a "charged or "non-charged" program) - Stephen Max is running on the charged side with the JWT ECU/Z32 MAF without issues.

Also, Z32 MAFs read both "suction" and "blow" - and you have to suck in x amount of air through the blower to put x amount through the piping. So the MAF should read the same either way.

The reason JWT says you shouldn't mount on the charged side is because all that air is pressurized and more forceful. But it's the same amount of air nonetheless.

Someone else either cooborate that statement above or tell me I'm wrong - but I don't think I am.

Anyone else have any ideas?

 

Wow, 3.71 V is enough for about 300 hp worth of air, it's no surprise you're running rich. I'm surprised it ran at all.

You were measuring the maf volts with the SAFC, right?

Are you sure you got the wiring right for the Z32 maf connector?

 

I checked it a few times using the diagram from the JWT site.

on the Tomei Connector:
black/silver = signal - connected to A32 white/green
black=ground - connected to A32 black
brown=ground - connected to engine bolt
White=+!2v - connected to A32 Red

 

The more I think about it, the more it seems like the MAF is the issue. Good thing is we have schuss Z32 to test the maf on. Should also test the new EEPROM with the A32 maf just to make sure the car still runs, granted it may not run very pretty, she should still run.

And again...STOOPID park neutral switch.

S

 

What do 5th gen owners do when they get to the 350hp mark. I know that the 350z injectors work, but what about the MAF. Can we get the 300zx MAF since there motors of the 4th and 5th are pretty much the same, right?

 

Maybe the MAF out of a 350z? (I think it's the same however).

Anyway - tested the MAF on schuss' car today.

Works great. Reads 1.45v at idle.

So the MAF is NOT the problem.

So I guess this EEPROM just will not work with this ECU at all. Still doesn't make sense to me however - the A/F System is no different on any Maximas from 1995-1998....

 

are the B-E pins in the correct order? All connections solid? did you cut the max harness off and replace it with the tomei?

 

I used wire taps and checked everything with a voltmeter against my friend's 300zx to make sure I have the wiring right.

I get continuosity between the signal line and the ECU at the harness, 12v where I should be getting it, and 2 grounds as I should be. (B is signal, C/D are ground, E is +12v - just like the JWT diagram says.) I verified this on the Z also.

The wiring is solid.

BUT - I got a PM from Stephen Max this morning and he mentioned air leak and FP in the same paragraph.

Then I remembered - when we put the piping back in after changing the MAF, I don't think we hooked the vacuum up to the BOV. The BOV happens to be tapped into the FPR.

So I would have been at 50 PSI on Fuel Presure, and about 5 on the vacuum.

I don't know if that was enough to make it crazy rich like it was (the garage instantly filled with smoke) - or to make the Z32 MAF read 2 full volts over where it should have - but it's a theory. So after work today if I have time - I'm going to try again.

I'll post here my results.

Confused - What Bar is the FP programming on this EEPROM? THat also may be an issue since I'm at 40PSI at idle.

IanS

 

His programming is for stock FP.

 

do you have a fpr?

if you do then you can mechanically adjust it.

doesnt stephen have his cartech set to 1:1, cuz he wanted the adjustability?

 

I don't have an FPR, but will definatley need one to pass emmissions later this year because I will have to put my stock ECU back in and unhook the SC while running the 370cc's.

What effect will running a lower base FP using an FPR have on the car? Isn't higher FP (as long as it's not over the injector tolerances) better?

I'm thinking about just getting another EEPROM programmed for 3 Bar of FP from JWT for a 1995 ECU....thereby solving the issue using a program and not mechanics.

IanS

 

no, basically if you have the base fp as stock, you are making the 370's dump in about 100 cc/min more than stock so you need to lower the base.

isnt the 370 base 24 psi?

 

It will lower your max FP at WOT unless you compensate with a FMU, therefore your max BHP will be lower, ie you'll have less fuel pressure head-room to work with.

 

So - what you're telling me then - is to stick with the 40PSI base and get the EEPROM programmed for 3 Bar of fuel.

If 24 is base, then that really explains why I was running INSANELY rich - I was dumping a sh*tload of fuel into the engine because i was at 50PSI with the BOV vaccum disconnected....like I said.

 

no, run stock maxima base... 32-36 PSI. I have this setup... Did you check for any air leaks? if your Vaccuum was at 5 I would want to look at that first.

 

I got a Cartech fmu because I wanted to provide some extra fuel pressure at low vacuum (in the 3 to zero in. Hg range) which is where I was running a little lean and getting some light knock during partial throttle acceleration. (I have since pretty much convinced myself the knocking was due to a bad TPS adjustment. More on that in a different thread.) The Cartech has the ability to produce additionial fuel pressure before the onset of boost, as well as having a variable rise rate. Besides, it looks so cool.

 

Ian,

A few comments.

1. 3 bar is ~45 psi, which is the standard pressure that injectors are designed for. Manifold vacuum helps pull fuel out of the injector, that is why fuel pressure at idle reduces to ~34 psi. The pressure differential across the injector is kept at 3 bar with a 1:1 oem fpr so that its flow characteristics don't change due to manifold vacuum (or pressure). So the 3 bar program is the standard JWT program and is probably what you already have, unless confused had it programmed differently.

2. I feel strongly that the 3.7V signal at idle coming from the Z32 maf is why you were running so rich. That is a very, very high signal, and if that is truly what the ecu was seeing, then it is no wonder it was dumping fuel into your engine. You have to determine what is causing that. Since the maf worked in schuss' car, then the maf is okay and it has to be a wiring problem.

3. Is your car running normally with the A32 maf and the JWT ecu you bought from brodaiga?