performance Auto Vs Manual

[ehsnils]

Oh no!

http://www.bedug.com/pics/Fun2/i-divided-by-zero.jpg

[Garandman]

Whatis the performance impact of having an automatic vs a manual GT Limited? Is there still decent mid range accelaeration, not only off the line? What about the various shifting modes and how they work on an automatic?

 

I am leaning towards a manual but having a much harder time finding one and wondering if i should hold out.

 

Thanks

Yes, hold out.

 

Subaru Australia has performance data on the different models.

[Richard B.]

44+55=99

Oh noes!

It's 44.3% front, 55.7% rear

 

 

bah...

 

hahaha...you know what i meant.

[Richard B.]

Not true. If you think all the VB mod does is increase line pressure, then you obviously don't know how IPT mods the VB. A TCU hack would help, but the VB mod goes even beyond that.

 

 

true. i thought all they did was rework the thing to get higher line pressure.

[Richard B.]

you need to shift sooner.

 

good info tho.

 

 

shift sooner?

 

i swear i do not get that power drop. pulls allthe way to shift point. even in 3rd. 85-100 is pretty good.

[issai]

Performance auto = swap our 5EAT's out with the new 370Z's "7EAT"(?). That 7-gear auto tranny response to manual mode input is nearly lightning-quick. I admit I felt a bit disappointed getting back into the 5EAT.

[VTGT]

^Do you know if the 7EAT is a Jatco unit?

[issai]

A google search with "370z automatic jatco" yields quite a number of hits. Can't speak for the reliability of the results, though.

 

But man, that 7-gear auto is a sweet, sweet toy to play with... the 5EAT feels tremendously hesitant in comparison.

[Jerboa113]

I have to say when I read "7 speed transmission" on nissan's site, I was suspicious that it was some kind of CVT hybrid.

[fishbone]

true. i thought all they did was rework the thing to get higher line pressure.

I don't want to re-write everything so I'm just going to copy/paste what I wrote in another thread. The best thing to do would be to crack and reflash the TCU and get an IPT VB. That would be awesome. The IPT VB is tamed down to the point so that the TCU doesn't get upset. So by being able to edit out the ROM data, you'd be able to firm up the VB even more.

The truth is we don't EXACTLY know what IPT does. That's more or less intellectual property/trade secret/whatever you wanna call it. But if you talk to any tranny geek they'll be able to tell you. Do you have a basic understanding on how the transmission works, as in engages gears? Don't read between the lines because I'm not being bashful, I'm just asking I'm FAR from being a connaisseur myself. Consider it's inner workings in regards to the accumulators and solenoids (which are, simply put, electronic valves).

The accumulators, from what I have been told, when the gear engagement comes about and the valve body re-routes the fluid, they will swallow some of that fluid to soften the gear engagement. If there were no accumulators, the impact would be damn hard because you'd have ALL of the hydraulic pressure in the line going into that shift. By modifying the spring ratio/functionality of these accumulators, it basically allows for more hydraulic pressure to be applied to the clutch packs. This achieves two things:

-quicker engagement

-firmer engagement

Picture the accumulators being your left foot on a manual. The rate at which you let the clutch pedal out defines the quickness of the engagement.

Firmer engagement is a big plus because you are essentially increasing the holding capacity of the tranny. Back at stock power levels, the "mushiness" of the engagement of the clutchpacks was not a big concern because the tranny wasn't "fighting" a whole lot of torque. But when you increase the power, all of a sudden that slipping becomes noticeable and harmful, because now the tranny has to struggle to clamp down all that extra torque.

Enter solenoids. I'm not entirely familiar what gets modified as again, only IPT knows, but by changing their behavior, from what I understand it allows for a lot quicker routing of the ATF and hydraulic engagement of the right gears. This, again, means quicker shifts.

 

How is this not harmful on the driveline? Because the valve body could be modified a LOT harsher. IPT had to test and find the allowed tolerance without messing with the electronics/TCU. Look at it from the reverse angle of a manual tranny. How is it NOT harmful to slip the clutch with EVERY gear shift just so your passengers don't feel it?

 

In the long term you accomplish these things with the modded vb:

-increased holding capacity

-less friction on the clutches

-less wear and tear on the clutches

-potentially less heat in the ATF

 

There still IS some slip, but by a significant amount less. Also, there is very little "wait" between gears. Does that make sense? The stock tranny shifting behavior is somewhat like this:

-disengage gear

-wait a decade

-go grab the next gear

That "wait a decade" bit had some of us bangin' the rev limiter like it was prom night. Not to mention "flare-ups" or up-slips of as much as 500 rpms.

My 2nd to 3rd gear shifts at WOT or under load/full boost were sorta like this:

-disengage 2nd

-rev-up about 200rpms

-go and softly grab 3rd gear, only to either hit rev limiter or slip the clutches some more

[fishbone]

^Do you know if the 7EAT is a Jatco unit?

Yes it is. JATCO is a subsidiary of Nissan, so Nissan has pretty much nothing but JATCO trannies.

[05GT Guru]

Yes it is. JATCO is a subsidiary of Nissan, so Nissan has pretty much nothing but JATCO trannies.

 

If its anything like there weak manual 6 speeds it wont last long under hard driving.

[fishbone]

I'm not aware of the 6-speeds being weak. At least I aven't seen complaints from the Altima/Maxima/Z owners on the boards I frequent

[05GT Guru]

I'm not aware of the 6-speeds being weak. At least I aven't seen complaints from the Altima/Maxima/Z owners on the boards I frequent

 

My friend John is on his 3rd in 40kmiles, my aunts g35 coupe is on its 2nd or 3rd in 50kmiles. The just start grinding bad after 20kishmiles. The dealer told my aunt they fixed the problem in 06 so they put a 06 tranny in her g35 and it started soing it again 10kmiles later.

[issai]

^That's surprising considering how all the various long-term reliability reports for the G35 paint a nearly spotless record for that car. It's always good to hear what really happens down in the trenches.

[lawl]

My friend John is on his 3rd in 40kmiles, my aunts g35 coupe is on its 2nd or 3rd in 50kmiles. The just start grinding bad after 20kishmiles. The dealer told my aunt they fixed the problem in 06 so they put a 06 tranny in her g35 and it started soing it again 10kmiles later.

 

sample size of 2. not doubting the facts, but when arguing a generalization it helps to give a bigger sample size.

 

some people just cant drive manuals correctly... maybe you know 2 of them

[fishbone]

Not doubting there have been problems out there, but the JATCO units are pretty stout, except maybe their 4EAT units that are equipped on the 02-04 Altimas. There's been a few folks reporting slipping at over 70K miles on the units. Mine started slipping 1-2 clutchpack at around 65K miles. The VQ puts out quite a bit of torque and the 4EAT gear ratios weren't the best I've ever seen.

[i_c_the_light]

The automatic is about as useful as a plotline in a porno.

 

Unless you have one leg, then buying one is stupid. If your S/O can't operate a clutch pedal, then tough shit.

[Richard B.]

The automatic is about as useful as a plotline in a porno.

 

Unless you have one leg, then buying one is stupid. If your S/O can't operate a clutch pedal, then tough shit.

 

 

the title says "performance".

 

your opinion is about as useful as a plotline in a porno.

 

you aren't even CONUS.

[Richard B.]

I don't want to re-write everything so I'm just going to copy/paste what I wrote in another thread. The best thing to do would be to crack and reflash the TCU and get an IPT VB. That would be awesome. The IPT VB is tamed down to the point so that the TCU doesn't get upset. So by being able to edit out the ROM data, you'd be able to firm up the VB even more.

 

 

so basically...just tighten up the line pressure by modding a ton of parts?

[fishbone]

Did you read my previous post where I quote myself that long-drawn reply? Pay particular attention to the part with the solenoids. Tightening up the line pressure is one aspect of it. It will increase the holding capacity of the clutchpacks by basically holding down with more force, but you still have to look at the rest of the parts to cut down on the time it takes to disengage one gear and engage the next. If the fluid isn't being routed quick and/or flowing freely, it doesn't really matter how much pressure it's throwing at the clutchpacks because you're still leaving a facet on the table untouched.

Keep in mind the 5EAT shifts at full WOT and full boost. It is one of the inherent beauties of having such a unit. But also it's downfall and undoing. You do NOT want it to spend a whole lot of time in between gears because the engine is still pushing torque in the unit and the tranny WILL uprev between shifts. It's one of the BIG reasons I went with the VB. 1-2-3 shifts my tranny would uprev and slip down about 300-500 rpms.

Why don't you try this experiment sometime. Put it in manual mode and roll in 2nd gear under 2K. Then step on it and upshift in 3rd at around peak torque. Watch the results. It may not be as obvious if you don't have a stiff tranny mount. That or, well, there's a difference between pushing 16PSI and over 18 around that area in revs (2600-3600)

[jasone]

what fishbone said

[Platinum_Racing]

*skips thread*

 

I'm gonna say it... And only because i know you americans looeeev your stupid f*ing auto's...

 

If you buy an auto, you are a muppet, and you fail. Enjoy your slush-box and your fail.

 

Maybe it's because our country is way bigger than yours. The average commute to work is 42 minutes around here... Now at 5AM who the Hell would want to be shifting and trying to chug that coffee at the same time? Don't get me wrong, I like manual trannies, but sometimes it's easier to go with an auto... Especially if it's got an autostick like the Legacy. Since your country is about the size of Colorado, my guess is you could probably hit a golf ball to work. Not the case over here. We commute for everything. We also buy gas by the gallon, not the liter, so we don't have to drive like panzy's all the time to avoid breaking the bank on fuel costs (Although it was getting pretty expensive for a while there... Cough*GeorgeWBush*Cough).

[Jerboa113]

my commute is only 25 miles but it takes me over an hour. I'm VERY glad I dont daily drive a manual. I'm glad the 5EAT however has a "manumatic" option however.. because despite spending over $1000 on a simple brake upgrade I can still not out brake a ford explorer and have to use it on some mornings to engine brake just to keep from getting in a 3 car pileup.. and at only 35mph too.

 

Also when I find the 1/8th of a mile stretch of road on my commute that doens't have someone on it just before the old woman cuts me off from that neighborhood then flips me off and goes 25.. its fun to slush my own gears for a few feet.

 

right.. Bush's fault gas prices were high.. he pushed the "make shit expensive" button in the whitehouse.

 

well guess who just layed a large stack of heavy books on that same button? we're about to see $200 for a loaf of bread.

[fishbone]

Guys, don't feed the trolls. I was born and raised in Europe and I readily recognize the advantage of both MT and AT. I have not seen one single automatic unit until I set foot in the US. None of the two are the end-all, be-all. You will hear polarized opinions generally coming from asshats that lack perspective, experience or both. Some people need to get over themselves and have some serious emotional growing up to do still.

And for the record there are more and more autos cropping up in Europe. I was surprised to see them in my home country. Ask an average Euro why he/she didn't opt for an auto and the first thing you will hear is fuel economy. The second will be higher initial cost. Third will be a mix bag of lack of performance/don't like how it feels/I'm skeptical of it's reliability/etc. But now autos are finally starting to build a reputation for themselves over there too for being pretty darn reliable if treated right, good performers. In a sense I consider my European fellows backwards in this regard.

You have to realize every little penny and drop of gas is accounted for with a MUCH more aggressive stance than in the US, because everything is much more expensive over there. That is why some European car manufacturers have come up with such good performing autos (DSG, SMG).