I'm a little confused right now. My car was making 253whp/250tq at my last dyno. Since then i removed the vias. Recently I installed 400cc injectors and a custom adapter plate and the 09 tb. I was runing a little rich after a rough street une. Today I went to the dyno and installed the 80mm BBMAF. I have been under the impression that these two mods would significantly increase horsepower, yet it did not. In fact, as you can see by the dyno's i lost about 40 tq and 25 horse below 4k rpm. After 4k rpm everything is about the same.

so what the hell happened? I'm thinking i need to put the VIAS back in there because the power loss is insane. it's the only thing I can think of. Either that or gutting the Upper intake manifold.

I 've been reading how a 4" MAF makes huge power increases (mine is 3-3/8), but it seems to me that the larger bore MAF caused a huge decrease in air velocity which is definitely showing up here.

Run 6 is the new run. Run 12 is the old run that made the better numbers. We didn't tweak the AFR to perfect. My tuner said it would be a waste of money to tweak it to perfection when there was something definitely not quite right.
Actually i'm not sure how to get the AFR to pop up on here, but suffice it to say it is between 12-13 for the run.



So the question is how do I get my torque back?

Here's a pic of the BBMAF installed.

 

No idea, but I noticed that you don't have a vacuum line on the vias solenoid anymore, and the vacuum can is gone, too.

Read through these two threads.

http://forums.maxima.org/5th-generat...dyno-fail.html

http://forums.maxima.org/dyno-discus...sis-fixed.html

Since it's cheap and you can do it yourself, I'd say it's worth a shot to hook up the vacuum part of the vias assembly and see if that does anything.

 

Could be a timing issue related to the IPW and bigger MAF, which seems plausible since peak #'s aren't greatly affected. Do you know your before and after timing #'s?

Also, do you have a test pipe? If not, I'd suggest getting one. I've proven that a TP can greatly add/restore torque in the 3000-4200 RPM range.

Also, do you have an SSIM or just a BOP? IMO, functioning VIAS + stock rev litmer = Win. SSIM + extended rev limiter = Win. Stock limiter + SSIM = Loss. Extended limiter + functioning VIAS = loss.

What were the exact differences since the last run?

 

Since last dyno I removed the vias. Afr did not seem to change so I left it as is. Recently added 400 cc injectors and ran with a rough fuel cut to get by. Last week I installed the 09 tb. Last night the 80mm MAF.

I did not check timing from last dyno run. Numbers were good and I was happy. So went for the tune after the bigger MAF install. He added a lot of fuel and we did 3rd gear runs. But when we saw the power loss we called it a day to save money.

I can data log the new timing, but even knowing that I have no way of knowing where timing should be. Am I maxed out or is it going to be retarded?

Torque pro (android) says timing is 45* cruising. Not sure if I trust that though

 

Yeah, my timing looks the same cruising.

Check the timing under 100% load, as in WOT in gear as a function of RPM. That's the best way.

400cc, are they 390's or 440's @3.5 bar? Just wondering since I've never heard of 400's. Either way, that's probably not the problem.

I still have a hard time buying into the VIAS power loss deal, but it's worth a try. Also, but this would be more of a band aid, but a test pipe really does help torque in that area.

 

370@ 3 bar so about 399.69 at 3.5 bar. Not sure what car they came from, but they are the fbjc-100 style. And they are dark green.

Ok so assuming I can get the timing datalogged, how do i tell my tuner it should look? Can someone post a graph of rpm vs timing so we can ball park it next time?

 

This curve is slightly aggressive.



These are with various stated of MAF voltage conditioning.

 

That's great! Thanks Manny, I will do a pull or two on the way to work tomorrow when I get onto the highway.

 

to get the AFR in winpep.

right click on graph
click properties on bottom

far right tab axis selections.

right under power, click that and select AFR

if the dyno had a wideband hooked up this data should be in the runfiles.


this is starting point #1 in finding out the issue. its easy and quick info!


My dyno numbers changed quite a bit just with tuning fuel, you could have a totally different car between 12, and 13 AFR. (im tuned on 13.4 afr) little on the lean side seems to make the most power. 13.6 is really my limit. while 13.2 is too rich for my motor.

i re read the thread and seen most of your issue is under 4k, so i doubt its afr related unless its reallly off under 4k.


something is def up thought. in for timing #'s

 

My old tune was at 12.5 and we would have aimed for that again, but when we saw the power loss we decided to call it at an hour. Dyno tune is 200/hr up here so there was no use tweaking it to perfect with the power loss. After 3 quick pulls in 3rd gear it was obvious that there was something wrong. He's not a Nissan guy, and I didn't do enough research to know that the bigger MAF messed with the timing.
I'm on my way to work, grabbing the laptop and I will use the emanage to datalog a 3rd gear pull onto the highway.

So If I see the timing is out , can I just add/subtract timing when i get home, or does that completely mess with the tune ? I know in the past when I had my first tune, dandymax took a look at how much timing was added and just took a big block in the emange blue and added a ton of timing. Shaved about 1 second of my 1/4 mile time and added a few mph as well. But I didn't have a wideband at the time so I have no idea what else changed.
At least now if I change something I can see if the AFR is bad.

I have a question. So increasing MAF size adds timing, does increasing the injector pulse reduce it? As you can see my timing is flat like a torque curve. LOL This is a WOT 3rd gear pull from this morning, starts at or around 19.5 seconds




Manny a few questions about the first map you posted. Is that with or without the VIAS. Second, what did you use to log that?

 

this is my curve from a wot run when i had the 3.5 intake and n62 maf or whatever bmw v8 maf it was.

 

Well, I definitely went at this the wrong way. Now I'm wondering if I can tell the emanage that I am using a z32/q45 MAF. Would.that give me a better timing curve? Obviously I would have to cut fuel with.the z32 setup and add for the q45

We told the emanage it was a "stock" vq35 and added a ton of fuel.

Does anyone know if telling the EMU that i am using the maxima hotwire, but the z32 MAF, will it change how timing is done? Or is that just a quick fix for AFR?

 

Why don't u just add timing via the emu?

 

Timing is dependent on what the maf sees on the ecu side. Thats why tuning with safcs and such reducing duty cycle/fuel via maf hack advanced the timing. Using the ultimate intercepts the injectors, so increasing fuel independent of the maf won't do anything on the timing side, because the maf is out of the loop. Adding timing with the ultimate, you need to know what you are doing. You changed the vias and the maf at the same time, so I believe that was an issue, you basically changed the timing curve, and need to log it see where you need to adjust. It is either shifted left or right due to intake changes imo.

 

I did the vias delete over a year ago. But I didn't dyno the change. It didn't seem to lose any low end power, and the butt dyno felt more power up top. it did not affect AFR. But for all I know deleting the vias helped in the low end loss I am seeing right now. On top of that timing is only at 12* idle right now when it used to be 17, so I have to add 5* minimum at bottom end. But that wont account for 40tq loss. I agree this was all done wrong.
My main problem really was updating from the EMB to the EMU and not keeping my old tune. I should have loaded the old tune and just told the EMU that the MAF size changed. I can grab my old tune, it is on another car on the forum.
My other option I think is to put the VIAS back on and the old MAF, do a run with the old tune and grab the timing numbers. Then put the BBMAF back on and adjust timing to the old numbers, then adjust AFR. Or just tell the EMU that the MAF size changed and tweak from there. (I don't think the EMU has an option for an 80mm MAF. Nothing Japanese anyway.)

I'm still trying to figure out what all the hype is about the BBMAF because as far as I can see I won't have any more top end power when all is said and done. I'm pretty sure timing is about as high as it can be at the top end, so playing with timing at the low end is not going to give me any more power at the top end. Right now at the top end the car is right on the edge of wanting to ping, and that is at 12.5 AFR. There is no way my tuner will try for the 13 range.

Dyno tune up here is 200/hour. I don't feel like paying that to someone while we tweak timing a degree or two at a time trying to find the sweet spots.
I need to go back on the dyno, but it has to be in such a way that it doesn;t cost me a friggin fortune.

 

thats why you want to run a larger intake/maf size.


well long as you can tune correctly for it.

 

Well, it looks like I am pulling too much timing on the low end, and have about 6* more than what manny posted for most of everything above 3k rpm.

Hey guys, I was wondering, the pulls with the low numbers were only done in 3rd gear as opposed to 4th. Will doing 4th gear pulls make the numbers a bit higher?

 

FWIW, on the SAFCII I'm telling it I have a Q45 MAF. And yes, I had basically the same issue.

I lost timing and torque when switching from the 3" housing (custom) to the LRMAF. I made more power with the 76mm vs 82mm. And then i decided to do some timing runs and noticed it had dropped quite a bit on the order of 8-12º depending on where on the curve.

That's when I decided to get larger injectors, and also a larger MAF housing. Did some raw calcs: http://forums.maxima.org/8519606-post284.html And here's the explanation behind the timing curves I posted earlier:

http://forums.maxima.org/8525888-post288.html
http://forums.maxima.org/8525888-post288.html
http://forums.maxima.org/8526688-post291.html

In the end, with the new set-up, I have fairly aggressive timing, comparable to my old set-up even though I'm adding about 20-24% fuel via SAFC (very raw %/voltage #). This is with Doug's 4" intake and 440cc injectors. Little extra info here: http://forums.maxima.org/all-motor/6...2-08-vq35.html

 

Get a real engine management system... problem solved!

 

for 2k I'll buy a different car. LOL

 

you got that in other mods..


anyway tho.


car should pickup good power once you get tune right

 

As long as my AFR/timing and CVTC curves are good, I think I'm OK. Just don't have the time to be tuning as much as I used to. Although I would like to get my hands on one jsut because this fooling the ECU stuff is a bit on the difficult side with lotsa side affects that need to be fully understood before going at it.

Also, my MPG read 44.5 this AM and my DTE was 485.

 

I'm down to 8.3/100km, used 450km this tankful and I have another 600k til empty. ( I wish) ROFL

I was at 9.2 before the dyno.

 

I still get actual 24MPG mixed, which is what I typically do even before the injectors, and 27MPG or so highway. They didn't make any difference of actual for me.

 

Highly doubt its a VIAS issue. Air velocity could be a issue because it might be bottlenecking from not having a SSIM. I believe your timing is very confused down low. A 40whp loss is very noticeable, do you feel the loss?


This is a impressive timing curve sir!