CAI (Bigger piping where the MAF inserts?) and a ported intake manifold. I'm guessing the ported IM might be the culprit?

 

Those sort of changes will alter the intake resonance. Good? Bad? :shrug: the actual physics are beyond me.

Hell, it could be a vac port on the manifold suddenly getting more air from somewhere - I'm not sure how much air it takes to run significantly lean.

 

I see dip in torque from 3K - 3500. Maybe something can be done to massage that out? Aside from that, from about 3500rpm onward nice torque increases. That should definitely be noticeable.

Here's a map from a bike from a while ago. Removed secondary throttle plates + tune/exhaust/air filter. Low end throttle response was impressive (same for hp at rear wheel too!).

https://i.imgur.com/Vs3xqKy.jpg

 

Correct me if I'm wrong, but don't his new torque numbers mean an increased feel to initial throttle response?

But you're right, low 3K takes a small hit before it smooths out, both in torque and HP.

 

3500 looks like throttle tip-in to me. AFR is still really high for WOT.

Did they mess with throttle response? (IE, accelerator pedal responsiveness). Or it could be some voodoo re: automagic transmission.

 

@Rochester Right, but aside from gains, one of the functions of a tune is to try to reduce/eliminate flat spots or dips. Sometimes not possible.

Example below is from the bike on the left. Stock, low end actually had a flatter torque curve, but after tune, slipon and airfilter, gains were still impressive.

https://i.imgur.com/WFtXHpE.png

 

OK. Makes sense.

But what if that's the compromise, and it can't be smoothed out? Only RMB5190 can say, but in other words, are the overall gains worth that little hic-cup? I bet it is.

 

Edited RMB5190's initial post - but it sounds like he got better driveability AND power. That sounds like a win to me...

 

Absolutely. Any gain is a gain, so long as the dip is still above the initial amount Man, looking at those bike graphs brings back memories....

 

To my knowledge, there was no actual TCU manipulation for throttle response but he mentioned toying with something in the VVEL to reduce the lag when stomping on the throttle suddenly or 'tip-in' response...I can't rember exactly how it was described and I'm sure I am butchering the explanation. At the 3000-3500 range, he was hesitant to toy with it too much given the degree the cam was already at? Basically, he said the VVEL was maxed and any more would probably result in knock so he gave it a slight tweak and left it alone.

Besides the more linear power delivery, the throttle response when going WOT and the up shifts at WOT are the most noticeable difference. Unless you daily a 7AT and experience a number of WOT pulls, it's hard to explain that insane sluggish delay when going from cruising to WOT for a pass or the wall that is hit when approaching the 7300 soft limiter. The best I can put it is, before, the car would come on steady and feel like it was going to pull hard after 5,500 but it would just seem to hold up the closer it got to redline. Then, the shift would be similar to riding the clutch for too long when going WOT in a manual car. Now, there's really no 'hesitant' feeling as the limiter approaches and the shift feels entirely different.

Overall - yes, absolutely worth it for that hiccup in the beginning. The car behaves normally unless you go WOT (which is a good thing). I only did one pull from a dig on a road i'll occasionally open it up on. In 70k miles of ownership, I've never reached the speed I did at any point pre-tune. The launch and the bark my tires let out on the 1-2 shift really caught me off guard as an added bonus. In my opinion, if you have all the basic bolt-ons, a tune is a must.

 

I suspect you're right. And yet I keep pushing the tune down the list. Someday...

My next big mod project is brakes. And even that's not until next year.

 

That's next to complete. I have the entire BBK set-up already, including calipers and pads and SS lines, but have just not found the spare time to knock it out.

Thinking after that though, I'll be done modding the car and will focus on longevity. For example, I know my water pump has got to be taken care of soon.

 

Tune might be my next thing since I've got all the basic bolt ons... although it's so hard to find a local tuner with an AWD dyno who works on these cars. Anyone done those remote tunes?

 

Washed clayed and sealed with ultima paint guard plus. Still need to polish exhaust tips.

 

So the Q50 will be gone in 5 days and a new Infiniti will take its place. Did the paperwork today, coming in next Monday. 2019 Majestic White QX50 ProActive.

(generic photo)