Accelerator/ECM update

[haggisgood]

Hello .. I am a newbie here and I am glad to find this site. I bought an '02 Q w/ premium package, chromed 18s etc for $13,900 .. 85k clean title.. ..Took it to the Ininiti dealership for the update.. apparently update was already completed.. (vehicle was apparently still on the dealer lot when the bulletin came out)..Question: This update is supposed to shift the vehicle from 1st through 5th gear.. when I have the vehicle in drive.. and click it over to the manual mode.. it shows 4th gear.. then I down shift it to first gear.. the acceleration difference is like night and day.. similar to what I thought would happen when I heard about this update..Is the vehicle indeed leaving in 4th when in "D"? If not why would the 4 show once clicked over to manual and why would I notice such a huge difference seeing the update is already completed?.Anyone s input would be greatly appreciated.Thank you..Haggis

[Q451990]

Welcome to NICO! I'm not completely sure what you're asking, but I know that on our G, shifting from auto to the manumatic side typically downshifts the car one gear from where it was on the automatic side. Then you can upshift and downshift (within reason) by pushing the selector toward the plus and minus marks. I don't know, but I think the update had more to do with the shift points in automatic - and with a revised accelerator pedal with a weaker spring?

Heath

[maxnix]

Accelerator pedal has no spring if it is updated and will not pivot on the accelerator lever.

[mcrews]

The "update" was to cure the hesitation that happened on semi hard acceleration.No the care is not starting in 4th.When you move the shifter over after you reach cruise, the manual shifter drops to "drive" gear or 4th gear. Fifth gear is overdrive.D shows on the screen when in the "auto" mode.when you manual shift, the gear # shows up.also, when you are going down the road at 50 in auto "d" you are in overdrive. gear 5. when you pop over to manual it drops to 4.

hope that answers your question.

ps..Welcome

[MinisterofDOOM]

then I down shift it to first gear.. the acceleration difference is like night and day.. similar to what I thought would happen when I heard about this update.

Does the '02 "skip" first and do 2nd gear starts in favor of comfort? If my math is correct, first gear final drive is pretty aggressive (nearly 12:1 ) so I wouldn't be surprised if normal starts (in auto mode) use 2nd gear.

[mcrews]

Does the '02 "skip" first and do 2nd gear starts in favor of comfort? If my math is correct, first gear final drive is pretty aggressive (nearly 12:1 ) so I wouldn't be surprised if normal starts (in auto mode) use 2nd gear.

There was so much misinformation about the 02 based on the problems with the models before.I remember....oddly enough, that Brain was spewing about transmission coolers and othe crap, that had nothing to do with the 02s.

I will pay attention tomorrow and get back with you on that. Maybe one of the real techs will answer first.

[mcrews]

Does the '02 "skip" first and do 2nd gear starts in favor of comfort? If my math is correct, first gear final drive is pretty aggressive (nearly 12:1 ) so I wouldn't be surprised if normal starts (in auto mode) use 2nd gear.

Doom,yes, normal D starts in second.Ist gear starts in manual are VERY tight and quick

[xerexabante]

Mcrews,

I have to try this. I never knew the D starts in 2nd.

HOw was the move ti Cali?

[mcrews]

Mcrews,

I have to try this. I never knew the D starts in 2nd.

HOw was the move ti Cali?

I was always so pleased after the upgrade that I never thought about it either!!!!!Doom got me to thinking about how tight first gear was that I tried it.Started in manual 1 and man does it pull.!!!!!!!started in D and could tell the difference.

[Q45tech]

Hopefully this background will be usefulL

The 2002 Q had a 2.764 differential and a 3.54 first gear multiplying out to 9.78 total gearing starting off. [90-93 Q = 9.85] statistically the sameThis is the functional equivalent of the 90-93 Q except the gears are reversed. The 2.764 differential coupled with the 5 speeds 0.834 [5th gear] created a very economical highway cruise top gear of 2.305 ratio. [90-96 Q had top gear overall of 2.455 and 97-01 Cima had 2.564, 2002= 2.305 and 2003 = 2.612].

The loaded radius of tires acts like a gear. 12" is a foot so the foot pound numbers match but 12.5" [center to pavement] would need a -4% correction. I will skip tires here as members can calculate their own very fine corrections if they care.

The public and magazine test expected more acceleration from 2002 Q, so the 2003 Q got a higher rear diff of 3.133. This 13.3 % bump up via the diff was very noticeable between 2002 and 2003.

Unfortunately the 2003 then turned 13.3% higher rpms at the same cruising speed sucking more gasoline per mile.

For some reason Nissan forgot to note this on EPA sticker and used the same test for MPG as earlier gearing even though the highway dropped by 1.0 MPG minimum probably closer to 2 MPG above 55 mph.

Noone called Nissan on this but it was eventually fixed in 2008 EPA test.

Current M45 is the rocket [at expense of fuel] with a 3.36 diff gear and 3.83 1st gear turning 13.5% higher cruise rpm than even the old 90-96 Q geting 2.5 MPG worse fuel consumtion on highway at steady cruise.

But with 30% higher multiplication in 1st gear it is a real rocket.

From an economy perspective the 2002 Q is the best of the bunch, even though it is a little slower accelerating.

Just like a seesaw with MPG sitting on one seat and performance on the other.

What is interesting is that the same weight, same engine displacement Q/M 18 years later gets no better REAL MPG than the orginal. Isn't PHYSICS wonderful.

Hopefully the new 7-8 speed transmission can find a way but I am doubtful especially with the displacement bump up to 5.0 liters

[xerexabante]

I tried it yesterday and was so pleased about this. Oh yeah did it pull.

I also tried going the speed limit and got 21.6 mpg side street. already got 60miles at 1/8 tank. I was just steady cruising accelerating normal with the civics around here. Just a light tap on the pedal to get to 45mph. My car will stay on manual mode from now, just not to forget to have it on 5th on the freeway.

[xerexabante]

At 65pmh I am at 2k rpm

[Q45tech]

"At 65pmh I am at 2k rpm" EXACTLY

2.305/2.45 = ~ 6% less rpm so instead of turning 2,165 rpm [in a 90-96 Q] at 65 mph you turn 2,000. 6% fewer injector squirts per time period

As I said the 2002 Q is the more economical steady rpm cruiser compared to 2003.

The CIMA 41 [97-01Q] confuses the picture with a smaller engine turning more rpms thanks to a 3.694 rear diff gear which turns 4.4% more rpm per mile yet is almost 8% smaller so NET NET in theory the lighter 97 [vs 90-96] should see 3-4-% better MPG than any of 4.5 engined Q even 2002.

[mcrews]

I tried it yesterday and was so pleased about this. Oh yeah did it pull.

I also tried going the speed limit and got 21.6 mpg side street. already got 60miles at 1/8 tank. I was just steady cruising accelerating normal with the civics around here. Just a light tap on the pedal to get to 45mph. My car will stay on manual mode from now, just not to forget to have it on 5th on the freeway.

albert

I have posted in the past of my mpg.driving just at speed limit 66, 71, 76, whatever is posted, I can get 23-26 on a 3-500 mile trip.again as Q45tech says, the 02 is geared the best.I cant rationalize getting a smaller car when this BEAST gets such good milage.....oh yes, I do run 255/45/18 not 245. so in town I suffer just a little but on the road

[Q45tech]

Just wait for the return of National 55 MPH limits.............to save imports and Polar Bears. Speeding will become a Felony with shoot to kill to avoid fuel consuming chases.

Georgia already has a $12 Fuel Surcharges [per Police car involved] on moving violation tickets.