Puppetmaster

iTrader: (48)

You can see for yourselves. So yeah, I'll probably need lots of feedback and help with this, but here are some initial thoughts/reactions that I had:

1. I'm getting about 225 whp and 205 tq on average. Something is very wrong here. Run 11 had the AF tuned pretty nicely, but the numbers were still crap probably because it was the 11th run in one hour. Regardless, I got no torque and don't expect it would have been any better even if we let it cool down more.

2. The graphs, esp the torque graph, look awfuly "jumpy", even with correction factor 5, is that because there's something wrong with the car or the way the dyno was reading the rpm signal? They used a coil wire, cylinder 4, IIRC.

EDIT: I noticed is that my torque starts to climb from 5500-6000 where most 02-03's start to fall then. There is also a drop and subsequent rise in torque right before 3000 rpms, where I have been feeling some hesitation-like acceleration recently (mentioned below). It seems that the torque curve is confirming that too.

3. The car doesn't feel right when I drive it... jerky with slight hesitation at around 3000 rpms. I thought it might have been related to the MAF signal because the hesitation only started happening after installing the VAFC-II.

4. Dyno operator said that only one of my VAFC-II maps could be used because it wouldn't switch from LVT to HVT. I told him that he had to set the HVT -> LVT and LVT -> HVT, but said he did and it didn't work (HVT points weren't responding to his adjustments). So basically he just used LVT (12 points) to tune the AF. At this point, I didn't bother arguing with him because I was worried more about the low (or no) torque than using both maps.


Relevant Mods:

Berk intake with K&N filter
Cattman Gen 2 headers
Frankencar b-pipe
Cattman rear section
VAFC-II

Other things to note:

Stock 17s
Timing not advanced



UPDATE:

VAFC-II unplugged and MAF reconnected and the car runs fine without hesitation or power loss. Will probably try to dyno it again w/o the VAFC-II

Puppetmaster

iTrader: (48)

As a very rough comparison, here is rbrown81's vs mine. He had similar mods at the time.



The difference under the power and torque curves is huge.

2002AltimateV6

iTrader: (7)

Check the installation. Your LVT and HVT should work, it works with mine atleast.

http://www.nissanclub.com/forums/sho...d.php?t=218832
Here are my results after my tune, not very happy w/ it since he was just adding on more fuel. Just make sure everything is installed, and try and tune it yourself? Looks choppy as hell.

Puppetmaster

iTrader: (48)

Thanks, but I knew all about your issues with running rich and bad tuning already; I posted exactly that in your thread. Post #21.

I'm not worrying about the LVT -> HVT until I get the torque issue worked out. I'm suspect that the MAF or MAF signal wire is the culprit, but we'll see.

NmexMAX

iTrader: (22)

The ony 2002 with a DEK..

rbrown81

iTrader: (3)

Ouch Joel

Dyno > you

How the F*$# do you loose all that torque... Its unbelievable.

steven88

iTrader: (28)

joel, didn't u say u started to get some hesitation problems after u installed the vafcii? iirc, you said the butt dyno felt great right after u installed the headers? i mean 200wtq vs 235 (average 2k2 header'd) is huge...and the butt dyno should pick it up....

i doubt headers is the problem here....i dunno...i mean willkim dynoed 260 something earlier...i'm sure with a good dyno operator, hes in the 230-240 range like normal 2k2s

NmexMAX

iTrader: (22)

Maybe a bad batch of fuel..

Puppetmaster

iTrader: (48)

Har har. At least my hp numbers are higher than a DE-K still...

Puppetmaster

iTrader: (48)

That's the question of the week.

Puppetmaster

iTrader: (48)

Headers shouldn't be the cause, unless I have a leak somewhere...

steven88

iTrader: (28)

a perfect way to check for exhaust leaks is SEAFOAM FTMFW!!!

haha but forreals...i use seafoam all the time and it works great to detect exhaust leaks....i think the auto parts store may sell some kind of fog to detect intake/exhaust leaks....i haven't asked....but i just buy the seafoam instead becuz it cleans my engine while i detect my leaks

vsamoylov

its not the headers for sure.

Derrick2k2SE

iTrader: (3)

Did you remove the the intake manifold during the instal? It could possibly be a vacuum leak or vacuum hose put back on wrong. I remember there were a lot of hoses which were hard to see. Check the hose to the VFAC. It almost looks like a 3.0 with broken VFAC.

steven88

iTrader: (28)

I doubt its a vaccum hose problem.....if his VIAS was NOT working...then the torque curve would look very smooth and linear....and you can see a dip in his tq curve at 3800...so that means his VIAS is working

HotshotVQ35

iTrader: (5)

wow, disappointing #'s. hope you get it sorted out

GBAUER

iTrader: (2)

It really looks like a vac problem to me. Maybe the purge valve is acting up? I had to replace mine because I lost a lot of top-end (stuck open). Maybe your's is stuck closed?

steven88

iTrader: (28)

umm...if your valve was stuck open u will lose low-end not top-end....and the 2k2 VIAS naturally stays open the whole time...only during under load, vaccum is sent to CLOSE the valve...then at 4k it opens back up and stays that way....if it was broken somehow, it would be stuck open the whole way...theres no way it will be broken and stuck closed....only the oovi and mevi is like this

and did you ever tear down your engine?

Deckdout2

iTrader: (151)

Looks like a pwnt to me.

Joel, that's a sucky situation. I hope it gets cleared up soon.

Puppetmaster

iTrader: (48)

So far I've had time to only check the vac lines and intake.... no leaks as far as I can tell.

Time to clean the filter and MAF....

GBAUER

iTrader: (2)

three weeks.

caSE

Are you comparing apples to apples? Manuals will dyno different than autos. Driveline loss with an auto is at least 15% but can be more like 20%. I don't think your numbers look that bad. The headers' primaries aren't long enough to boost low end torque that much.

Also are rbrown81 numbers SAE corrected? Smoothing? The key to using dynos for comparsion is to always use SAE smoothing (with the same window) and trying to dyno with the same engine temp every time. The car should be at full operating temp, pulling at temps of 140 don't give an accurate pull.

I dyno with smoothing set at 3. It seems your pulls have smoothing set at 0 (top right of graph). That would make your curves spikey. I think all is well.

Based on my dyno experience: Your A/F is still off, should be flat if tuned correctly. Your numbers look good if you have an auto, around 280 HP and 250 Tq at the flywheel. Your smoothing may need adjusting.

Dynos are tools, don't get caught up in the numbers, just focus on "before and afters" (on the same dyno) and focus on making a flat A/F.

Puppetmaster

iTrader: (48)

rbrown81 has a 6 speed as well. Drivetrain loss for 6MTs is typically around 18% and IIRC its about 22% for ATs.

Please look around this forum for other dynos of 02-03s with headers... even stock dynos of 02-03s, and you will see that the torque curves are way below what they should be.

Once again, look around for other dynos of 02-03s with headers.

I have his run files on my computer. I opened them in the same window as mine as a comparison. Therefore, the smoothing factor on both is the same. It was a rough comparison, I understand fully the pitfalls of trying to compare different cars on different dynos. It was merely an illustration to show where I stood compared to someone who had the exact same set-up as I did.

Those curves do not look normal even with smoothing set at 5. The torque curves are way below even for a stock 02-03 and they should NOT be peaking all over the place like they are on my car.

It has nothing to do with smoothing, the car has lost power and power delivery somewhere. I know what do to with my AF, but at this point, getting a flat AF isn't my top priority given what else is going on.

The numbers are not good, even if it is an auto. Like I said in the first post, there is something wrong that can be felt even when driving the car. It feels like a dog now, and its not because I got used to it. I can barely make the wheels chirp from 1-2 and there is no torque at all. The only thing "normal" is that I have good power from 5000 rpms up.

Cutler test drove it with me after I got the headers installed and he drove it 2 days ago: he could tell right away that the power is not there. SR20DEN also drove my car 2 days ago and also noticed that something was wrong right away.

I already knew that, but thanks anyway.

caSE

Wow. Thanks for the attitude-free reply.

If you want to rule out the way the shop dyno'd it than go to a different shop and give them $75 to make 3 more pulls.

By the way, your numbers show a 10% increase in power with some pretty simple bolt ons. I think you are expecting too much. You shouldn't believe everything you read (re: other people's numbers) Where you honestly posted your numbers most people like to fudge things for bragging rights.

You're curves looked fcuked. Agreed. The numbers aren't that low, especially with that A/F. (they really aren't, take emotion out of the equation and use logic. See, I can have an attitude too) Maybe try using a completely stock ECM and see how that looks.

Do you have your stock parts? Go completely back to stock and try it that way. See how your curves look and how it runs. That would be great since you could actually see what a "before" would be. I am actually trying to help.

rbrown81

iTrader: (3)

Case, I understand that you are trying to help but keep in mind you are talking to one of the most experienced members here on the org. I think you need to take into account that he knows a LITTLE more than you are giving him credit for.

And now for my 2 cents.

Puppet's numbers should have been a lot closer to mine. Yes not all cars will be the same, we know that. But look at my graph and look at his. Unless there is a ****ing frog stuck in the primaries, he should not be loosing that kind of torque! And his HP numbers are off too.

Case, I think it is you sir that needs to do a little more research on this topic. If you look at people like steven88 and sr20den, these guys are running similar mods (Intake, Headers, Exhaust) and a VAFCII and putting out close to 260/245 at teh wheels.

Something is definetly wrong here, and it happened when the VAFCII came in. That being said, do your research and come up with some more constructive comments next time you decide to post?

K thnks

IbebeatingonnoobsFTW!

caSE

You're right. I think I will just go for a ride in my 446 HP sunday driver that has been dyno tuned to a flat 13.0 A/F. Did I mention that I built the engine in my garage? Picked and matched all of the parts? Have an engineering degree and years of professional experience?

Whatever. I am sure that I know nothing. Especially since one post down contains dyno numbers of a similar car minus headers and catback and is posting similar numbers, yet somewhat lower due to exhaust. elgrande2003se has the stock catback, which has more backpressure than puppetmaster's. Hence, better torque. Puppetmaster added headers to offset the loss of b.p., but he would see better torque with the stock catback. No, not the 40 ftlb he thinks he is missing. I bet that elgrande2003se has good numbers and he was honest enough to post them. A lot of people (not just maxima guys, I assure you) tweek their dyno curves and numbers to make themselves feel better. Tuners do it a lot. It is good for marketing. Some tuners seem to have magic air around their dynos.

Puppetmaster is making the expected more HP than elgrande2003se for the difference in their mods. Yeah, his graph is screwed up, but the numbers are in the right ballpark. They are.

Oh, and I have been a member if the forum for 2 years. I haven't made 16402 posts because I do have other things to do with my time. I had a slow weekend and thought I might chime in on a few things while reading around. I assure you I won't make that mistake again.

Enjoy

SR20DEN

iTrader: (7)

Were there any differences after you zeroed the fuel trims? If not you might want to take the AFC out of the equation. It only reports the inputs from the APS and MAF, not what it outputs to the ECU. I could find no problems at all with the APS voltage and I didn't notice anything erratic with the MAF voltage either. But from what I gather, your problem exists in closed loop mode which is why I was trying to monitor the O2 signals and fuel trims. And you know we simply didn't have enough time to collect any legitimate data which is why I suggested you reset the ECU.

At this point it appears to be an issue relating to the output of the VAFC2. Try connecting the MAF directly to the ECU (possibly with those two supplied bullet connctors you were supposed to use) and let's work the problem from there.

Puppetmaster

iTrader: (48)

I did the reset procedure when I got home Thursday night but that didn't change anything. I agree with you that the AFC is probably the culprit given all the checks we've done so far. It will be taken off sometime this week. I'll try to get a hold of you later tonight or tomorrow.

Thanks for taking the time out help me out with this ... sorry that all you were rewarded with for that was a trip to Denny's...

steven88

iTrader: (28)

Dennys!! country fried steak and biscuits!

rbrown81

iTrader: (3)

Honey, you want chicken fried steak? or chicken fried chicken?

SR20DEN

iTrader: (7)

I had the CFS and it was good, as usual. I didn't however appreciate my coke being mixed in with someone elses rasberry iced tea. That drink was nasty.

steven88

iTrader: (28)

coke and rasberry ice tea...hMmm!?!? i always get strawberry lemonade....

if matt got CFS, then what did you get joel?

rbrown81

iTrader: (3)

So fellow header lovers... how the hell are we going to fix this?

Joel... I was thinking that there may be benefit in removing the VAFC from your ECU and seeing if that fixes the torque problem.

Are you certain that the wiremap is done correctly?

Is it a real VAFC? Maybe thats why it doesnt work properly. Compare serial numbers to someone else who has one. I know Apexi has had a lot of problems lately with counterfeit products going around

See Below
http://www.apexi-usa.com/news_special.asp

I know this is just a turbo timer, but it is possible that these counterfeiters may have moved onto the VAFC's

Puppetmaster

iTrader: (48)

Country fried chicken with scrambled eggs FTW.....

Puppetmaster

iTrader: (48)

??

That will be done soon. See post #27 and 28.

Yes, already checked it several times, and like Matt posted, only the voltage signal to the AFC unit can be checked (and they are correct), not the signal to the ECU.

No idea... it was used off eBay. It was cheap and if it turns out to be bad, I'll just chuck it or see if anyone who wants to figure it out is willing to buy it for cheap.

rbrown81

iTrader: (3)

I love it when you quote me... lets see a bibliography biatch

steven88

iTrader: (28)

Btw, joel, any word on the vafcii disconnect?

Puppetmaster

iTrader: (48)

Haven't had time to do that yet. Been squeezing in little jobs here and there. Crazy week.

Puppetmaster

iTrader: (48)

Disconnected the VAFC-II and my torque feels like its back. Need to find some time to dyno, but I can totally feel the difference. The power delivery is not jumpy and there is no "hiccup" anymore.

I did use some crimp bullet connectors, to reconnect the MAF, but I doubt that made the difference since the soldered joints looked good when I cut em. Maybe I'll reconnect the VAFC with those connectors sometime just for the hell of it to see if it was the soldered connections. Its just possible I got a busted AFC. I need someone else to put it on their car to try and see what happens.

NmexMAX

iTrader: (22)

No dyno no care