RichMax

iTrader: (2)

I am- finally- boosted. Here are some of the issues thus far:

lift off throttle at anywhere above 2k rpm and I get a whooshing sound... isn't that too low an rpm to get compressor surge?

My V1 makes a "cricket-y" sound. Any way to correct this or lessen it to a straight whistle?

My idle bounces ever so slightly (about 50 rpm and is at about 500 rpm when idling), and I have so-so (semi-hard) starts. I suspect this is because my MAF harness faces downward instead of towards the battery. I read the sticky about rotating the MAF, but never having taken one apart, how do I do this so that the charge pipe holes align with the MAF holes? Or should I just find an adapter plate, and if so, where?

Also (and I HOPE this is related to the MAF) There is a LOT of lag when I am accelerating. I don't think it is the tranny (I am an auto). When I get on the throttle, acceleration is not linear until the car gets above 3k rpm, and each time I have had this happen I have been too scared to take the car over 3500 to see if acceleration remains linear. The car "wallows" under full throttle between 2200 and 3k rpm. From a standing stop this is VERY noticeable, coming off of part throttle this wallowing is SOMEWHAT noticeable. I know better than to think I will be flamed for having an s/c'ed auto...

Right now I am untuned I am also on the stock A32 MAF and driving blind
I have a CEL for the MAF as we speak...

Seems like this is about more than just rotating the MAFS.. I apologize...

ewuzh

iTrader: (20)

The V1 is supposed to whistle pretty loudly. I used to have one. But if it makes a cricket-y (chirp,chirp,chirp,chirp), then it could be bearing noise. Make sure the belt tension is set correctly. Too tight of tension puts extra wear on the bearings and too loose could result in belt slippage and/or jumping ribs.

The stock A32 MAF shouldn't need to be rotated. The whole "rotate the maf" issue applies to the Z32 MAF. There's no way to rotate the stock MAF with the original stillen piping unless you cut the piping and reweld it of course (and by doing that, you'll probably also have to extend the MAF harness wires cause it won't reach the plug). But if you have a CEL for the MAF, then its probably a sign that it's busted?

abci30

iTrader: (11)

i get some compressor surge down that low, depends on which bov you hvae. The idle bouncing around could also be the bov not set correctly. I had some lag down low before and it was a maf. Somehow i sucked something up and stuff clogged up the maf and damaged it. I put in another one problem fixed. BTW i didn't have a check engine light when my maf was dying. Glad you got your car running sorry i couldn't come by and help with the install.

BlackCat

iTrader: (6)

Thats normal for an auto tranny. Boost kicks in at around 3000rpm.

RichMax

iTrader: (2)

The reason why this is problematic to me is because between 0-2k rpm the car isn't wallowing as described earlier. It's a little slower than N/A, which I expect since the s/c is purely parasitic at that point... but it accelerates fine. The car is in first, and bogs down like the ac compressor is on or something... at around 2200 rpm all the way up to 3k.

BlackCat

iTrader: (6)

You may have some air leaking. Check for leaks around the collection pipe.

RichMax

iTrader: (2)

That is a distinct possibility. Another question: If I install an SAFC-II, aren't I essentially taking the MAFS out of the loop, so to speak, and therefore it wont matter if I have a bad MAFS or not? After my mechanic (Jeff @ MaximumTuning) finished my s/c install, he advised against two things: an 00vi upgrade and the E-Manage over the SAFC due to the sheer proportion of people who can't get it to work (as opposed to the 5 or so people on the org who we know have it working). I'd like more precise control over my car, but... I guess my question is, is the SAFC method of control and measurement so imprecise that it is bad for our cars? The way I see it, I have no way to measure incoming airflow accurately with the SAFC-II- any suggestions besides going to the E-manage?

The Wizard

iTrader: (43)

I 95% sure you still need the MAF while running a SAFC. Someone correct me if I'm wrong. If you go EU, then the MAF can be removed, assuming you set the program options correctly etc etc . But, regardless, you shouldn't worry about the SAFC and EU, 00VI right now. Fix the problem at hand. Did your car run perfectly before the SC install? Only upon the install, did you get the code for the MAF? What BOV do you have?

ewuzh

iTrader: (20)

With an SAFC you will definately need your MAFS. SAFC modifies your MAF signal, increasing or decreasing the value read in by the sensor, and sends the modified value to your ECU for it to do it's thing with the injectors, given the volume of air it thinks is coming in to the engine. SAFC's is just fine for making minor adjustments to the a/f ratio, assuming your MAF works correctly.

RichMax

iTrader: (2)

Next question...

If I have the A32 MAFS and A32 ECU, won't I have a problem with airflow over the maximum airflow readable by the MAF anyway? If the SAFC is using input voltage from the MAF to determine airflow, then isnt the SAFC limited to what the MAF can measure?

I guess what I am asking is, if my blower hardware is creating more airflow than the A32 MAF can read, then I will need a Z32 MAF even if I have an SAFC... right?

In that case, I'll need a Z32 MAF on my V-1 (2.87" pulley) and while running 370cc injectors (my current setup). So, back to my original question: how were people rotating the Z32 MAF considering the fact that the charge pipe will only align with the MAF in one direction? You can't pull apart the MAF (can you?)

The Wizard

iTrader: (43)

Since you have a 2.87 pulley, chances are you are exceeding the A32 MAF. However, you said you're not boosting and your car runs poorly. Did it ever run right and you were boosting hard? If so, then maybe you did damage the A32 MAF and it's time for the Z32 MAF.


People were able to rotate the Z32 MAF because a lot of us, including myself, have upgraded the charge pipe to 3". By going 3", you need an 3" aluminum adapter plate to connect the new charge pipe to the MAF. Now there's flexibility on rotating the MAF. With the stock stillen charge pipe, you can't rotate the MAF w/o cutting and rewelding the charge pipe. Make sense?

RichMax

iTrader: (2)

Makes sense to me.. Where did you guys acquire the 3" pipes and roughly how much did they cost you? That and where did you find new elbows to attach to your blowers and the adapter plates themselves?


The poor boost may be the result of an unplugged grommet after the MAFS (uncharged side). There is a hole large enough to fit my thumb through.

The Wizard

iTrader: (43)

Everything you need to know is in this thread.
http://forums.maxima.org/showthread.php?t=453847

ewuzh

iTrader: (20)

That doesn't make much sense. If you're using Stillen 4th gen piping, the MAF IS on the charged side. The only hole I can think of is the one underneath the upper 90-degree elbow for the air temperature sensor.

RichMax

iTrader: (2)

wrong use of terminology on my part as to where the maf is located...

The hole I am referring to IS on the 90-degree elbow connected to the throttle body. THe air temperature sensor is supposed to fill that hole? As of now it just has a rubber grommet (for what, I didn't know). The hole is on the underside of the elbow. If it is for the Intake Air Temp sensor, where the hell is mine??? I haven't had one in my intake stream since I put in an after-market intake 3 years ago....

ewuzh

iTrader: (20)

There's a good chance it is dangling in the engine bay somewhere, probably resting on top of your transmission.

The Wizard

iTrader: (43)

That's not good. Plug that hole up with the IATS, and you should be fully boostin'. I'd be a little pissed with whoever installed your SC. That's just plain careless. Let us know if this solves your problem.

RichMax

iTrader: (2)

not going to blame my installer.... Again, as far as I can tell, I haven't had one plugged into anything since I pulled my stock intake years ago. What harness would my IAT sensor be attached to, and would anything else be on the harness that would actually be plugged into something? I have a 99 Cali-spec.

A better question, perhaps, is, what does it look like?

RichMax

iTrader: (2)

Also, because the A32 ECU is reading A32 MAF sensor values (or thinks that it is) an SAFC-II is useless in conjunction with the A32 ECU if you have a smaller pulley, right? Isn't that true even if you have a Z32 MAF wired up, since the A32 ECU can't interpret the Z32 MAF signals correctly on its own?

My understanding is this:

The Z32 MAF has an output voltage range between two sets of voltages (I don't know what they are precisely.) The A32 MAF does as well. The A32 ECU has a lookup table or is calculating the amount of fuel to deliver based on A32 MAF voltage output values. When it sees Z32 MAF output values, without more, it thinks it is seeing A32 MAF output values and delivers fuel accordingly. But if, for example, the Z32 MAF output voltage is 1.0 volts, this means something different than an A32 MAF output voltage of 1.0 volts, right??


Does the above make any sense? I am having trouble seeing how the SAFC can fool the ECU into reading more airflow than the ECU is designed to read or than is within the readable range.

The Wizard

iTrader: (43)

I can answer your first question. The others I will leave to the experts...

The pulley size is irrevelant. The amount of airflow changes being boosted, and the MAF reads this and sends the information to the ECU. Obviously, the smaller the pulley, the more air is being pushed pass the MAF per time.

On a NA car, a SAFC-II can trick the ECU into thinking there's more air than what's really there, hence the ECU tells the fuel injectors to dump more fuel. More air and more fuel=more power. Hope I answered you question somewhat.

ewuzh

iTrader: (20)

With a 2.87 pulley at 13 psi between 5800-6500 rpm, you're going to be pushing a LOT of air through the charge pipes, too much for the stock A32 MAF sensor to handle. The A32 MAF just isn't able to meter that much air and you will exceed it's sensor's capabilities. If it can't sense the air and tell the ECU there is X amount of air coming into the engine, then there is no way for the ECU to know to add additional fuel, resulting in a dangerously lean condition. I think it's over 300whp when this starts to become a problem. This is where the Z32 MAF comes in. The sensor is able to meter a larger volume of air almost twice that of the A32 MAF.

More about how the Z32 MAF works (especially when paired with larger injectors and the stock ECU)...Reference this wonderfully wonderful and informative thread posted by I30tMikeD:

http://forums.maxima.org/showthread....ight=explained

RichMax

iTrader: (2)

so then a SAFC-II will not be sufficeient to ensure proper fuel flow with my 370ccs and a Z32 MAF... right?

ewuzh

iTrader: (20)

You might need to run higher base fuel pressure than the OEM 3.5 bar. Do you have a walbro fuel pump?

RichMax

iTrader: (2)

Yep. My assumption was that no additional fuel pressure-raising measures were necessary if you had my setup (2.87" pulley, 370cc, walbro 255 lph hp). Is that correct?

abci30

iTrader: (11)

with the 2.87 pulley, 370cc injectors, walbro you will still need to bump fuel up some more (FMU). Most people are running 550cc and walbro with nothing else to raise fuel levels.

RichMax

iTrader: (2)

A question:

what is the behavior of the fuel pressure regulator if there is no vacuum line attached? I ask because I was advised by my mechanic that it could be kept attached to my fuel line and an adjustable fpr could be attached. I only want to keep them in series because the screws attaching the fpr to the fuel rail seem impossible to remove.

abci30

iTrader: (11)

when you get an afpr you will need an off fitting which replaces the stock pfr, or you can hallow out the stock one and leave it in place.