450sx part 2

[GSXRJJordan]

Originally Posted by gsracer

jordan... that is exactly what i thought. So i did that.. and I'm having trouble with the signal dropping out. Im watching the ecu its seeing .550 volts at idle then it starts to drop (rather quickly) to .080 which is effectively off. Then it comes back up to .550 range.. Kinda like how an oxygen sensor signal would do, or instability in the signal.

I assume you have the VDC probe on the white wire, what are you referencing for the ground? Black wire inside the twisted pair? When the MAF voltage is dropping, is the ECU pulling timing, meaning is it for sure a sensor problem or is the engine literally not pulling in any air?

Does it scale properly with load as RPM's come up?

[gsracer]

Originally Posted by GSXRJJordan

I assume you have the VDC probe on the white wire, what are you referencing for the ground? Black wire inside the twisted pair? When the MAF voltage is dropping, is the ECU pulling timing, meaning is it for sure a sensor problem or is the engine literally not pulling in any air?

Does it scale properly with load as RPM's come up?

im monitoring the voltage off of the ecu, the black wire twisted pair is going towards the sensor... the ground circuit is tied into my other main ground...

It was getting late and i called it a day, so ill report back tomorrow on the timing.

edit...
Thanks for the help btw.

[SicBastard]

You can try a screen just before the MAF to get more laminar flow. Either that or try a new MAF sensor. Cuz it sounds like you have the wiring down.

[gsracer]

update...

I think the problem lies in the ecu. The wiring is right.

I think the problem all boils down to the airflow. The stock maf reads .8 to 1 volt at idle, even with the engine chugging along at 400rpm it doesn't go below .7 volts.

With the hpx maf in the stock 3.5 inch piping at 800 rpms it reads .550 volts at the ecu then bounces to .080 (effectively off as far as the ecu is concerned) then back to .550 volts. I have tested directly out of the maf with a vdc probe and see .420-.450 volts when this happens.
Also when it does this it will trip a maf code in the ecu. However if i raise the idle to 1300 rpms it will read higher voltage function correctly and not trip a code in the ecu.

Ive gone back and forth from stock to the hpx, and the stock functions correctly, the hpx functions as well, i just don't think the stock ecu has the ability to resolve voltages below .550 volts even though there are tables for it in the ecu.

I contacted the developer of nistune to see if theres any hardware or software or code work around.

In the mean time it seems I'm stuck.

Either i go to a z32 maf and hope i don't max that.
or put the hpx maf in a 3 inch tube instead of the stock 3.5

Im sure the fact that this is in a blow through application doesn't help.

[SicBastard]

This is exactly why old guys are afraid of EFI. It sounds like going to a smaller intake tube should work, but it will cost you power. Even on cars only making 400 whp, we used to see a drop in hp with intake elbows below 4"!

Maybe it's time for a real stand alone?

I'm not familiar with the hpx maf, but since 2006 the GM LS7 has been running a cartridge style MAF, maybe it reads in a higher voltage range and would drop in? Aren't most MAFs 0-5v?

[gsracer]

most macs are 0-5 some go higher.

It would undoubtedly be better to run a real standalone, but I've seen people make almost 1000 hp on the stock ecu, I'm almost positive the problem is the coding with the way nistune works with the factory ecu in this application.

The real fact of the matter is that this software and hardware has been extensively developed for the sr / rb and ka applications, and for the vh45 I'm one of maybe five people on the planet running it. Most are in stock or close to stock applications so it hasn't fully been developed.

Im gonna wait to see what the developer has to say about it before i change anything, he's always been very interested in helping me and the other vh guys, so well see if its possible.

Another option would be a diablo sport mafia maf extender on the stock vh45 maf, it can give you up to 50 percent more resolution, many of the ford guys have great success with it.

[SicBastard]

It sure is nice when a product (nistune) is actually supported! I hope he comes through for ya.

[gsracer]

hows this for customer service....

Hi Jerry

It appears that the Nissan ECU code has a limit hardwired that if the MAF
voltage <= 500mV then it will set it to a permanent 80mV as a limp back
solution and set the AFM DTC code

It is not a configurable parameter. If you need this extra range what I can
do is customise the BIN file to reduce this to say 80mV so it will not
change it any more. Other vehicles like SR20s have this as a configurable
parameter

60U00 Q45 VH45 DE code

92D9 : FC 14 09 ldd MAF_LHS_MSB (AB) D=MAF voltage
92DC : 4D tsta check A != 0
92DD : 26 1C bne L92FB if so get out
92DF : C1 64 cmpb #$64 check B >= 500mV
92DD : 26 1C bne L92FB if so get out
92E3 : CC 00 10 ldd #$0010 peg voltage at 80mV

He's writing me a custom bin file to work at lower voltages, so this should be resolved soon, hopefully.

[vas570sx]

i hope everything works out for you dude, if you need anything, you got my number.

honestly though, after reading all of this, i dont think a Mafia will help you. It does a great job of extending the maf voltage to keep it from pegging, but it wont do much for you at idle or low rpms.

Is there no maf curve adjustment or maf scaler in nistune that allows you to adjust that low? i mean, the idea here is not to turn off the limp home mode, but rather to keep the maf V from dropping below 500mv, right?

[240cracker]

car is awesome!! my fav motor build forsure.

what are u using for the ecu?

it might have been mentioned but i couldnt find it.

[vas570sx]

stock ecu with nistune^

[SicBastard]

That's awesome. No hardware changes!

Mad Props to Nistune.

[onepuff]

Matt(Nistune) is a great guy. Helped me out with an RB issue I had.

[gsracer]

Well its done..

First off id like to thank Bardabe, we have never met and are on two different sides of the country, and he still spent two hours on the phone with me trying to help me figure out the problem with the hpx maf. Thanks!!!

Ultimately i had to scrap the hpx maf, I just couldn't get it to work with the computer and the motor. I ended up going with what i new i could make work, a ford lightning maf. So with the motor still running N/A i uploaded the new map started it up idled and drove fine on the first try... Did some street tuning, perfect so maf issue was sorted out.

Came back home, connected the intercooler piping, modified the map and such, went out for a drive, lightly at first good base tune, then when i went to get on it wide open the first time, I'm thinking man, its pretty slow. It felt at first like it lost power, It took me a while to figure out the throttle was hitting the hood, so i had to notch the hood.





Took it out again, back to normal. It seems like it has more mid range and top end. Hitting 4.8 volts on the maf at 7000rpm, which is something like 875 cfm so it seems like it might be making a little more power.

Another thing that was unexpected is the vtc on this motor switches at 4200 rpms and id tuned to the factory intake manifold. Now around 4-4500 rpm you can feel a surge in power when it switches off, leading me to believe that its flowing more air than the stock one did at that rpm so i may have to get on the dyno and play with the activation point of the vtc.

Also as for impression the power doesn't feel as linear any more, if you see the dyno of before the tq is flat pretty much across the rpm band, now as for feel it seems like its more peaky. So I'm optimistic for a decent gain at this point.

This is all from the butt dyno so ill try and make it to the dyno next week and confirm.

HEres the completed pics.

[soreballz]

Super rad. Keep up the good work, sir.

[codyace]

Awesome stuff man!


I hate to sound like the biggest ricer dickheaded forum loser evrer, but that freakin paint marker shit on the intake 'core' or whatever it says bothers me. If I send you an Ace Trucking sticker, can you cover it up???!?!?

[SicBastard]

That engine bay looks awesome. Glad to hear the butt dyno confirms success. Are you running an air cleaner, if not your rings will thank you after you get one.

[4-20sx]

Originally Posted by codyace

Awesome stuff man!


I hate to sound like the biggest ricer dickheaded forum loser evrer, but that freakin paint marker shit on the intake 'core' or whatever it says bothers me. If I send you an Ace Trucking sticker, can you cover it up???!?!?

do it...lol

[gsracer]

Cody... send it

sicbastard... i don't have any room for an air filter... believe me I've tried.

thanks for the compliments, can't wait to make it to the dyno.

[n8RPS13]

I'm friends with Juan and he said good things and was excited to help you out with this. Hoping we can meet up when I get back to SFL and make some runs haha!

[SicBastard]

Originally Posted by gsracer

Cody... send it

sicbastard... i don't have any room for an air filter... believe me I've tried.

thanks for the compliments, can't wait to make it to the dyno.

Then it's time to hack that core support, and install a >90 elbow to in front of the passenger front wheel. Even the most inoccuous dust is like sand paper to modern thin gauge rings. If I was you, I would be squirting tears everytime somebody kicked up dust in front of me thinking about the drop in compression that just happened. Your ring seal is going to shit. I know you can score longblocks, like I can score tube-socks, but still...

[n8RPS13]

From what I remember his core support is nearly nonexistent as it is.

[gsracer]

Well results are in... happy and sad at the same time. But everything is well.

Out of the box it made more power EVERYWHERE in the rpm band above 3000 rpm with no losses. Fine tuned the fuel map and timing map then ran into a problem, i was having an ignition misfire issue about 6500 rpm, and with even 1 degree of timing it would blow out the spark.

Aparently a 35 gap is to wide at this point for the amount of air its flowing, is sad to see the graph and see it picking up power until 6500 rpm but level off majorly after there. Luckiliy its a simple issue to correct and i would expect it to continue to make power after 6500 rpm. Its at peak boost at that point.

Overall it made the same amount of power peak, just more over all so not bad at all...

Heres the graph...

Before and after




Heres is the peak gains....




an

[SicBastard]

Instead of closing the gap why not upgrade those little COPs? LS2 coils or MSD HVC II Coils should do the trick. Over 40 ft lbs from an intake swap is awesome! Looks like all your hard work paid off. Congrats. Once the ignition is sorted I wonder how close you're going to be to 500whp!?

[turbociv910]

awesome gains for just an intake manifold.

[Yellow4g63]

Very solid gains even with the ignition problems!

[n8RPS13]

Damn thats impressive bro!

[Pinggg]

Good shit jerry! bump for another fl fella

[n8RPS13]

Originally Posted by Pinggg

Good shit jerry! bump for another fl fella

Florida Fail my ass! SFL FTW! Cant wait to be back!

[SicBastard]

What plugs are you running? I ponied up the cash for the NGK iridiums and had no problems at almost 20psi of boost on a stock miata.