I'm sure you guys have been curious to see this. I had to get one last hoo-rah before the partout begins. This was a completely UNTUNED run as if the air/fuel didn't give it away and the scatterbrain lines, but I had to find out for myself where my accomplishments have taken me. I'm sure you guys have been waiting for this as well for a while. There's definitely more room for improvement in the tune and even with a flatline air/fuel, there would be even more gains once I would have thrown timing at it. This was on a Mustang Dyno as well.

My build thread:

http://forums.maxima.org/all-motor/6...5-5gen-na.html

UNTUNED!! - 275whp

 

Impressive! Mustang dynos usually read lower right? I wanna see what this would put down tuned on a dynojet!

 

Mustang dynos generally read 5-10% lower, but that can change based on settings. They're also generally known to be better for tuning since they put a more realistic load on the engine... But yeah I guess seeing more inflated numbers would be neat even if it makes absolutely no difference realistically.

Either way, the thing to take away from this dyno (imo) is the beautiful shape of that power curve... Looking like it will make usable power out past 7500 at the least with a nice flat torque curve from 4k up

Pretty much every other VQ dyno on this forum peaks at ~6200 then drops off so it's obvious that the head work has changed that (considering he has the same cams, IM, and similar headers as JayPee, but not the same peak).

I wonder if that 5200 RPM dip that we see on a lot of these FWD VQ dynos is from the stock intake cam timing also dipping in that RPM range...

 

Congrat!

 

This is great man, was this done running stock timing?

 

This is exactly what I was looking at. That dip might be able to be smoothed out some from simple A/F tuning though. Only drawing this conclusion because the a/f dips suddenly also to what looks like 11.9 right around the time this dip happens. But I do believe that there is tons of power to be unlocked through out the entire power band through cam timing though. (which has been proven time and time again even with stock cams on RWD VQs)

I would have loved to see a dyno with a taller rev limit though to see where power starts droping off.

 

Yeah the only reason I'm not sure the dip is 100% caused by AF is because you can look back through 10+ VQ35DE dynos and see that exact same dip in pretty much every one of them. That 11.5ish AF dip definitely makes it look worse than it probably really is, though.

Can see the dip to some degree in each of these threads.
http://forums.maxima.org/dyno-discus...se-r-dyno.html
http://forums.maxima.org/dyno-discus...check-out.html
http://forums.maxima.org/dyno-discus...n-numbers.html
http://forums.maxima.org/dyno-discus...ew-dyno-s.html
http://forums.maxima.org/dyno-discus...03-maxima.html
http://forums.maxima.org/dyno-discus...ltima-ser.html
http://forums.maxima.org/dyno-discus...44-ft-lbs.html

 

Great #s, and the car still has plenty of potential.

 

Cam timing? Yes!

The guys here at CIN Motorsports told me that they've tried every single thing possible for years now on these motors to flatten that dip out with little success. They've gotten very close, but it's just the nature of these motors to have that dip. They did mention that the revup motors do not have this dip at all. I think this has is an old issue from the beginning of the VQ35DE that has minimal success rate across the platform. I would love to see the root cause of it as it's still unknown.

Thanks guys, I was very pleased to be able to pull this at the current stage it's at.

 

Actually, now that its put into perspective, I agree. One thing I've noticed also is that in some cases, the dip is more of a flat spot. Where hp doesnt necessarily drop off, but just hits a momentary plateau before climing again. Not saying this means anything at all, just pointing out that some cars do a better job at "hiding" the dip than others.

 

Yeah most certainly. Sometimes it looks like a flat spot or even a reduction in slope on the HP graph, but it will still be evidenced by a dip or quicker reduction in torque.

I'll be going to CIN to get a final tune once I have everything together sometime early this year... will be giving them control of AF, timing, and CVTC so I guess I'll get to see first hand if they can get rid of that dip.

 

Numbers look great! Looks like all the hard work and time you put into this Max produced something really nice!

Great Job!

 

Nice numbers especially on a Mustang Dyno I heard those are the true heartbreakers for people...

 

You might have to go and just borrow their dyno and tune it yourself. Ben and Bobby don't have much experience with the UTEC if you're still running it. They couldn't easily tune the A/F for me on this dyno run, that's why it was left alone. They would need to study the software and spend quite a bit of time with it. If Matt (SR20DEN) was there we would have pulled even better numbers as he knows his way around the UTEC quite well now. Ben and Bobby have a higher focus on the Osirus software and others. Just a heads up.

 

Wow thanks for the heads up. May go to a different shop if they are that incompetent. Getting the A/F straight on a UTEC is as easy as opening up UTI and UTI-ME, spending 10 seconds setting up the target AFR table, then doing 2-3 runs to get the A/F perfect with auto tune. Maybe go up and down a little after that to see if more power is made at something other than the 12.8-13.0 area. I can do this on ANY utec with current firmware on my laptop in the amount of time it takes to do 3 pulls with a short pause between. I assumed a big Z shop like that would have something already set up on a computer and ready to go when UTEC customers came in. The only reason I'm considering getting a tune done by a professional is because they have tuned tons of VQ35DEs and can get the AFR, ignition and cam timing perfect for the most power much quicker than I could, but if they'll be wasting my money and time fiddling around with A/F tables screw that.

I know Aaron got his tuning done at National Speed and they were familiar enough with the UTEC, I may have to road trip my way down there.

 

They're not incompetent for sure, it's just a system they're not familiar with. National Speed is a really good shop as well. Haydn took his G down there and they gave him a really good clean tune on his sedan.

 

Yeah it's just you know the hourly rates for tuning at that kind of shop and if they're fiddling around trying to figure out the UTEC, I'm going to walk out of there with a much bigger bill than I wanted or expected from a professional shop and possibly with a tune I could have done better myself. If a tuner at National Speed is familiar with the UTEC, I'll have to aim in that direction for sure, only tacks on about 4 hours to the round trip

 

LOL. I know all too well about tuning rates. That's why I have Matt fiddle around instead.

 

Freakin awesome #'s, and most importantly, that curve looks to have some serious potential.

Do you recall any of the settings were used on the dyno?

Weight, coefficient of drag, etc... ?

 

Re that 'dip', could it not be due to resonance tuning from the intake runners (length).....?

I only mention that because after doing some dyno tuning on a few NA and turbo tuned Altimas (first gen, regular non VIAS manifold) there was always a similar dip (at a different rpm) on the dyno...just a thought....

Jeremy

 

Normally resonance tuning from the diameter and length will result in something more like "humps" at an initial frequency then the harmonics of that frequency, the effect is also sometimes known as "dynamic supercharging." It's possible that the 3000ish rpm then 6000ish rpm "humps" in our powerband are actually the result of this and the 5000ish dip is not actually a dip, but just the area between humps.

edit: this can also be done with intake length before the IM. That is what causes the "AEM hump" for 200-300rpms on hondas.

 

I think SR20DEN has touched in this slightly in the past. And the theory behind it is when the intake is modified in between the TB & MAF from stock (read: straight pipe) this occurs.

I think he said, when a straight mid pipe is installed, the result of this dip is AFR, and of course it may be able to be tuned out, or at least leveled or regulated slightly.

I have a few dynos where there is no dip (SSIM & Stock) when I used the stock Helmholtz.

When I had a straight pipe in there and no Helmholtz, I saw this hump, no matter the IM.

 

Interesting... All the research I've done has shown that helmholtz resonators on the intake side merely help to reduce sound in certain frequency ranges since the intake pipe is decoupled from the runners via the plenum. Tuning primary runner length/diameter to take advantage of Helmholtz resonance as the intake charge bounces off closed intake valves so that the pressure wave bounces back (from the plenum, because of the effect of helmholtz resonance between the plenum and runner) just as the valve opens again was the only application I found that can actually cause small power increases ("humps" on a dyno) at certain RPM ranges that represent the harmonics of the base resonant frequency.

Could you post comparison dynos with it? I'm sure you don't get rid of your old dynos

 

That is interesting....I saw the same 'dips' on stock Altimas as well which is why I always attributed it to IM resonance...of course, the VQ is a different animal....In for more info!

Jeremy

 

Im assuming you guys dont really "feel" the dip though correct? Being that it only lasts a few hundred rpm. I doubt that it affects ETs that significantly. Sure it would be awsome if it wasnt there at all, but I dont think its that big of a deal. But i'm running a dek, so who am I to say.

 

On a 6-speed launched on slicks or DRs, it shouldn't affect the ET whatsoever. Especially with a 7k+ rev limiter. I am below 5500 RPMs for a tiny fraction of a second when I first launch if I let it "bog" a little bit.

Paramy may be able to feel the dip a tiny bit because of the coincidence with A/F taking a dive at the same RPM, but not likely.

I'm not really worried about getting rid of the dip or its effects on performance, just curious what causes it.