My Dyno Thread

[NmexMAX]

My dynos and what I've learned from them.

A33B 4AT Lesson # 1.
Link: FYI: Going to dyno : Midpipe vs stock res. 3.5L
Another dyno thread .. input appreciated
Date: 02-Feb-05

Reason: Prove/disprove 2 things
1.) GAB
2.) Stock midpipe vs straight midpipe

Mods: CMG1 headers/GAB/Berk MP

Number of Runs: 4

First run: Strange, as the operator was totally unclear as to how to run my car, being AT. He started @ 55 MPH, and WOT'd it, only to have it downshifted to 2nd, then upshift to 3rd, and tap the lockup torque convertor, which then results in a 'loop' on the dynograph. This is a cause of the RPM signal backing off a bit, thus giving a 'loop' in the signal, which directly affects hp/tq.

The Good: He ran it all the way to fuel cut, I assume, not knowingly.
The Bad: All the aforementioned lock-up tq converter talk, which was a
direct result of beginning the run too early (MPH/gear/RPM) for the vehicle being tested (4AT A33B).

Runs 2, 3, & 4 all had the same problem and 1 more. He was using the vehicles tach and not his own (true signal), which gave him false sense of judgment, so, he shut off too early on the remaining 3 runs. (~6k for each).

Conclusive evidence shows that a straight midpipe affects power delivery, but slightly increases top end very little. IMO, it is not worth it when comparing the curve. ). Removing the stock resonator (Helmholtz) dramatically increases sound, yet, doesn’t do very much for power. This has also been noted in the RWD version of this engine (I.e. Z midpipe etc).




Lesson # 2.
Link: 233 whp / 231 wtq 03 Auto

Date: 17-Jun-05

Reason: Prove/disprove the deactivation of the ‘power valve’ theory

Mods: CMG1 headers/JWT POP/17* BTDC

Number of runs: 2

The curve was identical throughout the RPM band, except pre 4k ish. This is a no brainer people. My buttocks dyno told me I had more top end power. But it was just a figment since there was no low mend, the top end felt stronger and power delivery felt more linear. I found/read this on another forum, and really like it/stand by it

On the road testing is notoriously inaccurate. You don't feel power so much as you feel change in torque versus time. If the car feels stronger up top, that likely means you are noting a surge or increase in power at a certain point. This is just as easily attributed to making LESS power down low as it would be to making more up top. This is the same sort of "feeling faster" that all of the OBD-II track pipe people experienced. Same peak power, less midrange, and thus the car would have a much larger slope in the power band between the midrange and the high RPM range of operation. This is why the butt dyno should never be used. If you are going to try to make more power by messing with sensors, then do so with proper test procedures in place. A wideband to verify the AFR, as well as a timing light to check for any changes to ignition timing from changed load readings, is really required. The before/after tests should also be done on a dyno with the variables as controlled as possible to verify the change in power.


If you are going to try to make more power by messing with sensors, then do so with proper test procedures in place. A wideband to verify the AFR, as well as a timing light to check for any changes to ignition timing from changed load readings, is really required. The before/after tests should also be done on a dyno with the variables as controlled as possible to verify the change in power.

It really holds true here.

[NmexMAX]

Lesson # 3.
No link/thread, since I was still optimizing, and didn’t want to post lower values AFTER a mod.

Date: 08-Jul-05

Reason: SSIM

Mods: CMG1 headers/JWT POP/OEM 17’s/17*BTDC


Number of Runs: 3

This is where I learned that optimizing YOUR particular set-up is best for you. I lost power when adding this mod ALONE. But have since optimized my set-up for this mod (SSIM). Yes it does add some up-top, this is clear evidence. Here’s some supporting evidence (more ‘in depth’ analysis if you will)




Comparison of recent run vs new one




Lesson # 4.
link: Consistency FTW
Date: 10-Jun-06

Reason: TS ECU

Mods: CMG1 headers/CM-b/GAB/MMEV5’s/TS ECU/17* BTDC

Number of Runs: 3

This one is very interesting. This is where I started thinking that dynoing in 2nd was best. I had 3 runs, and decided to try 2nd gear. Well, my 3rd vs 2nd runs were nearly identical, but the torques suffered with using 2nd gear. I have also seen this on other Maxima dynos (DEK equipped that is). These runs are actually quite bad considering the mods that were on the car. I blame this on the, at the time, boat anchor bandwagons (MMEV5’s). But these runs did prove that the SSIM was still doing its job.

[NmexMAX]

Proving the torque / 3nd gear theory:



Previous best vs this run:

[NmexMAX]

Lesson # 5.
Link: 233, again, but this time @6300 RPM
Date: 21-Apr-07

Reason: AFR check/tune

Mods: CMG1 headers/CM-b/GAB/TrakLites 2.0/TS ECU/17* BTDC/SAFCII/82mmMAF/New Exhaust Set-up/JWT POP/Berk hybrid/PLXR300 WBO2

Number of Runs: 5

This was when I was still under the assumption that 2nd gear was best. These runs are ok, but very lean on torque. Back to the drawing board.







Lesson # 6.
Link: 242/238
Date: 04-May-07

Reason: AFR check/tune

Mods: CMG1 headers/CM-b/GAB/TrakLites 2.0/TS ECU/17* BTDC/SAFCII/82mmMAF/New Exhaust Set-up/AutoZone Special Filter Short RAM/PLXR300 WBO2

Number of Runs: 4

This was basically checking out the new intake design. Very strange power delivery being so short and all. Made 10 whp more after 6.5k vs the last set of runs. I also found out that 2nd is not best if you’re a dyno queen, which I tend to consider myself one. I also have this theory:
http://forums.maxima.org/showpost.ph...39&postcount=4

This run vs the previous run:

All 4 runs that day, great comparison for the 2nd/3rd gear:

[NmexMAX]

Best run & AFR


Here’s comparing AFR w/ and without a test pipe. Lean graph = w/o test pips 9functioning main cat) the richer version is without a cat (test pipe)



Best & worst (1st and most recent)




So anytime I tell someone something, it comes from experience people.

This is a good one too:
The DYNO "Questions & Answers" How to get the most of your dyno experience.

[joebangaa]

Bookmarked!

[liqidvenom]

so did you re-tune for each different mod you did or one basic tune for everything at once?

I am happy you finally got your dyno so there is no more nagging about it.

[NmexMAX]

? The last dyno was nearly a year ago, so on ‘finally’ getting my dyno. I conditioned the MAF signal each time I dyno’d when I had something to condition it with (SAFCII). So, basically, the last 2 sessions were SAFC’d. I hate to relate the word tuning when screwing w/ a SAFC. Although, I did take it 1 step further and added Z33 injectors into the mix for indirectly adding timing, even more pseudo FTL ‘tuning’.

I still want to take the stock airbox a little further. I have seen the stock airbox support up to 230 whp, and the stock cat-back support 247whp, so I want to see the limit of them coupled together. And since it is too late for my catback to be considered ‘stock’ I’ll just refer to it as the stock 5th gen muffler + slightly modified (inlet size) airbox.

Right now, I would at least like to open up my air inlet a little more on the stock airbox, but at times I think this won’t do anything since, theoretically, and ultimately, the TB is the ‘show stopper’. But, then again, we all saw how opening the MAF size a little bit of benefited performance, so again, it couldn’t hurt. I’m not saying let’s all go but 7” intakes on, I’m only referring to at least matching the MAF size to the airbox/intake size. This dyno may or may not happen soon. Need to find the damn time.

But, ultimately, for the most power, I’ve got this little number ready to install once I get back from work travel:

[NmexMAX]

It consists of all 76.2mm ‘hardware’, with the small exception of the MAF adapter, which is 82mm. After some physical measurements / test fits, it seems as if I will not have to purchase a 76.2mm MAF adapter JUST so everything is the right size. A few couplers later, it will all bolt up, and I won’t have to ‘tune’ the lean’ess’ out of the idle since my PCV will be functional again.

This is how I plan on setting it up: JWT POP / 76.2mm MAF housing / Custom 76.2mm midpipe w/ PCV barb / TB Toss in some couplers & hose clamps also and some ingenuity to secure it down if the JWT bracket doesn’t do the job.

[sparks03max]

Looks awesome nmex, mine is almost identical to yours except it's all pcv and totally ghettofied compared to yours.

It's going on tonight (only going to run it at partial throttle) and I'm going to take it to a local shop and pay 30 bucks to get 1 run on the wideband and see what my untuned AF is

edit: I put it on and did a ECU reset, drove it around a bit... I got on it once and wow, way more responsive. *crossing fingers for the AF to be good*

The piping is only around 1/4" inch bigger than the stock maf housing, so I'm hoping it'll just be less rich but still safe.

[sparks03max]

Also, are you going to be getting a bigger TB? If so, what are you thinking of going with? I'd really like to get a TB next, but I'm just not sure what to go with that'd be an easy fit.

[sparks03max]

Ok so it put down 221whp 219wtq (don't have runfiles yet) with a 15:1 AF across the board. Yeah I'm not going wot again until I tune it.

[liqidvenom]

Originally Posted by NmexMAX

? The last dyno was nearly a year ago, so on ‘finally’ getting my dyno. I conditioned the MAF signal each time I dyno’d when I had something to condition it with (SAFCII). So, basically, the last 2 sessions were SAFC’d. I hate to relate the word tuning when screwing w/ a SAFC. Although, I did take it 1 step further and added Z33 injectors into the mix for indirectly adding timing, even more pseudo FTL ‘tuning’.

I still want to take the stock airbox a little further. I have seen the stock airbox support up to 230 whp, and the stock cat-back support 247whp, so I want to see the limit of them coupled together. And since it is too late for my catback to be considered ‘stock’ I’ll just refer to it as the stock 5th gen muffler + slightly modified (inlet size) airbox.

Right now, I would at least like to open up my air inlet a little more on the stock airbox, but at times I think this won’t do anything since, theoretically, and ultimately, the TB is the ‘show stopper’. But, then again, we all saw how opening the MAF size a little bit of benefited performance, so again, it couldn’t hurt. I’m not saying let’s all go but 7” intakes on, I’m only referring to at least matching the MAF size to the airbox/intake size. This dyno may or may not happen soon. Need to find the damn time.

But, ultimately, for the most power, I’ve got this little number ready to install once I get back from work travel:

geez relax, it was a joke about you wanting to dyno at maxus if u went.

man ur a tightly wound guy.

[NmexMAX]

Originally Posted by sparks03max

Ok so it put down 221whp 219wtq (don't have runfiles yet) with a 15:1 AF across the board. Yeah I'm not going wot again until I tune it.

Interesting numbers, what are your mods? Also, my AFR was actually lean as shat according to the dyno. But, remember the cat/lean issue,

[sparks03max]

My mods are simply the 3" intake. I'm pretty excited by such good numbers. I have the NWP spacers, cattman headers/ypipe/fastcat, and all the ES bushings in the mail, so I'm shooting for the stars and hoping for 250 with a tune.

My next planned mods after the exhaust stuff is installed is SSIM, bigger TB, and raised rev limiter via TS.

Yeah I asked them if I'd get an accurate A/F reading from that tailpipe wideband with all the cats in the line and they said "oh of course!!!" Plus I think my cat is a little clogged (from 100+k miles of age).

I just temporarily wired up a vafc to add a little fuel for now b/c IMO even adding a little fuel will put me in the 13-14s which should be ok with 93+octane booster and not getting on it much.

[NmexMAX]

I've also heard mixed stories / reviews etc for the cat affecting AF thing. I just decided to post my experience in this thread. The dyno dude was always saying, ya, it's a little on the lean side. And we all know that is 'typically' not the case with these cars, so i had trouble believing the dyno AFR w/ cat. I do recall that our (dyno & mine) AFR's were nearly identical, but this data was taken after I added a test pipe, and prior to then, I did not have a WB.

So in conclusion, this does state that, in my situation, the cat did affect the reading.

[sparks03max]

Well I'm thinking that I'll be running rich enough with my headers installed, anyway. If the headers cause even close to as much of a fuel increase as most people claim, that should put me pretty close to 13.0...

If I ever get ECU pinout diagrams for the 03 350z and my maxima, I'll install my UTEC instead of using this vafc.

[pbn85]

Originally Posted by NmexMAX

I have seen the stock airbox support up to 230 whp

were you referring to the dyno-tune I did late last year when I got 230/240 with the stock intake or was this another incident? And also, the stock intake was completely stock, no GAB or larger midpipe or anything like that...just a k&n drop it

[NmexMAX]

Originally Posted by sparks03max

Well I'm thinking that I'll be running rich enough with my headers installed, anyway. If the headers cause even close to as much of a fuel increase as most people claim, that should put me pretty close to 13.0...

I think you're assuming way too much. Save for a WB prior to getting out of hand with the taking out / adding fuel thing.

Originally Posted by sparks03max

If I ever get ECU pinout diagrams for the 03 350z and my maxima, I'll install my UTEC instead of using this vafc.

Are you too lazy, or just don’t know where to get them from? Because if that’s the case, I will shoot you dead right now. I’ll send an ICBM to wherever you are.

Originally Posted by SLVRMAXX

were you referring to the dyno-tune I did late last year when I got 230/240 with the stock intake or was this another incident? And also, the stock intake was completely stock, no GAB or larger midpipe or anything like that...just a k&n drop it

This is correct.