Aggro_Al

TELCO119

I'm a little confused on how this applies to the 350Z or G35C 5AT. Could you clarify what you mean by "catch up". The 5AT on both cars use a lock-up torque converter. A locked-up TC is just like it says locked-up to the output of the engine. I don't happen to see where there is slippage or "catch up". When the TC is unlocked, it will instananeously flash straight to the stall speed of the TC and at the same time it will torque multiply. This is why dragsters use torque converters. A standard transmission has to rev to speed.

The only signifcant performance difference between the 5AT and the 6MT, besides torque multiplication from the TC, that I can find is the final drive gear. Put the stock 6MT FD in both cars and they will dyno very close to each other. Even with the taller FD the 5AT dyno results overlap the 6MT dyno results. A stock 6MT will be only slightly higher than a stock 5AT on average.

Also, could you explain what conditions would keep me from keeping my 5AT in the engines power band? I can't seem to replicate the problem that you described. I would like to know so that I can avoid or work around those conditions. Thanks in advance.

ares

iTrader: (2)

gearing does not have a large affect on dyno output. people dyno in 2nd, 3rd, 4th, doesnt matter, their are slight differences, theres something people seem to like about 4th being a 1 to 1 gear. but if you adjust for it, it shouldnt matter. youll get minor differences between them, not the 15-20hp that is seen.

FYI there are autos that have the same gearing as manuals out there, and it still holds true. its not really something that can be argued like I said. not saying HP is everything and a manual has more therefore, its faster. not true. but it IS true that a manual puts more power to the ground, and as such, THEORETICLY is faster. this assumes shifts happen as quickly(difficult and a bit rough), and without fault(unlikely). the whole manumatic thing somewhat removed the power band arguement which used to be quite true. and even when manumatic first came out, it was still true(computers would override you sometimes) but to my knowledge the Z will do whatever its told without question, except maybe let you shift to a gear that would over rev. not sure.

Risk

I think everybody is losing sight that the auto is a 5 speed while the manual is a 6 speed. Allow me to restate that I have owned both (G35c 5at and 350z 6mt) and the topic Im addressing (gearing=speed) does not take into account the weight or wheelbase difference between the cars. I challenge ANYBODY to go out and drive a 5at Z, then drive a 6mt Z....after both cars/trannys are driven (as I have), you will see that the 6mt stays much more in the power band than the 5at does. Then, take both cars to the track and drag them. You will once again see that the 6mt is the quicker of the two. I have a neibor who recently bought an '04 touring with a 5at who Ive smoked on one occasion from a stoplight in a fair race. He even came up tp me afterwards and said "man, that was cool how you were chirping in between gears." The 6mt Z, stock for stock is faster than the 5at Z. Deal with it!

JonsilvZ

When you say "smoked him"by how much? I did race a 6mt Z(CAI)driver on the street who ran a 13.5 at the strip. Nobody here ran that time with stock tires and CAI. We did runs several times when I was stock. He got me by a half car from 0-100. He started to pull at around 90mph. Oh yeah he was powershifting. Now you think about it if I had the same gearing as the 6mt?

Risk

Well, he launched better since I was spinning a little (my VDC was off), but I quickly regained traction and I would say that I got him by 1/2 a car in every gear (including shift times). We went to about 80 and I was over 1 car length ahead.

JonsilvZ

He obviously doesnt know his car too well

Risk

I think youre missing my point. Actually, come to think of it, what I just outlined IS pretty consistant with magazine test findings as well (the 0-60/quarter mile difference between the two).

ares

iTrader: (2)

an auto owner doesnt need to... there are finer points, but generally, its a matter of pressing the gas. a little finnesse not to peel, and maybe even power brake for some launch could be in order... but we arent talking about working a clutch. of course this is an advantage to a manual. race 10 times and the manual will mess up at some point. even more important for bracket racing.

capnfrantic

"well theoreticly, stick is faster. no matter what, that torque converter is spinning in the fluid, along with lots of other stuff; and that is drag. go dyno a automatic and come back telling me its the same, its roughly 15-20hp less actually. and that is not particularly debatable."


Rats! First I had to get over the feathering issue and now this...I bought a new Z with 15-20 HP less than what I thought!

"The 6mt Z, stock for stock is faster than the 5at Z. Deal with it!" You won by how much again? Man your friend has alot less horsepower!

Nothing to do but go sit in my Z and cry....

SEzzz

they both have pro's and cons. i like auto on muscle cars. my vette was auto and it pulled like a jet engine. cars like the z are better in manual in my opinion. more control, not necesarely faster. downshifting and all.

cwerdna

Umm, currently, horsepower ratings for all cars are ALWAYS at the crank. They never advertise wheel horsepower. Manuals inherently have less driveline loss than an automatic.

If you want the amount of loss you have w/a manual but want automatic shifting, you'll need something like an SMG transmission.

JonsilvZ

A stock 6mt Z dynos at around 240-? Auto Z dynos at around 230-? So there is about 10whp difference. Most 6mt Z drivers here run 14-low sec. Very good drivers in the high 13s. That is damn close when I have 10whp less.

Aggro_Al

Risk,

Which magazine did you read where they did a comparison test between the 350Z 6MT and the 350Z 5AT? It would be interesting to see how much of a difference they got.

TELCO119

Sorry, I was away for a while. The term powerband reffers to the RPM range where the most power comes from. Most Z's don't even wake up untill 4500 RPMs.

"catch up" was reffering to roadhandling. For example, We both go down a twisty road, you with an auto and me with a manual. We go into a sharp turn together. As we come out of the turn we both floor it. Your auto is in the 3K range, but because I downshifted two gears, I am in the 5K range and walking away from you even though your auto "shifts faster". In the time it takes your RPMs to get into the powerband, I am long gone and you are trying to "catch up". Even if you put the auto in "manual mode", it still doesn't fully compensate for the gearing difference.
Somebody stated earlier that you could put the same final drive ratio in both transmissions for a fair fight. This is true, but we were discussing Auto vs. Stick, in stock form.

SteveZ33

I do what you do in your manual all the time with my 5AT. Coming out of any "sharp turn" I can always tap it back at least 2 taps putting the car in 2nd or 3rd coming out of the turn. I can be in any rpm range that I choose just like you. Am I missing something that you said?

1sick350

iTrader: (1)

so does it feel the like it pulls just as hard? Cause im prob gonna have to get an auto casue around here its annoying for stop and go traffic to clutch all the time plus the z is my first car and i can drive stick yet. I dont wann learn on the z casue im worried about messing up the tranny. Im just hoping that it has the same feeling in pull.

Aggro_Al

Better check your sources if you are implying that SMG doesn't have any loss due to hydraulics. SMG and F1 have electronic hydraulic shifting like the 5AT. Here's a link to a copy of BMW's SMG Manual that corporate distributes to their dealer's and it clearly states that the SMG uses hydraulic fluids.

http://www.m3smg.com/files/smgmanual.pdf
BWM SMG Dealer Guide



On the Z the most significant amount of difference between the 5AT and the 6MT is the FD and like JonsilvZ said on average it is about a 10rwhp difference at peak HP with some overlap but a lot of people forget to look at the whole graph. In the mid to low range you will see that the 5AT is better at torque management. In other words, a stock 6MT will put down higher hp on a dyno but a 5AT is better at keeping the engine in its power range. both the 6MT and the 5AT have similar driveline losses. The peak power difference is mostly caused by gearing in the Final Drive gear not by driveline losses.

Neglecting normal driveline loss, the factors that determine how much power gets measured on a dyno are:
1)Wheels/Tires
2)Final Drive Gear/Trans Axle
3)Transmission Gear Ratio

Let's use the a 350Z Enthusiast in both 6MT and 5AT as our comparison cars.

Wheels/Tires: No difference because they use the same wheel package.

Transmission Gear Ratio: There is no difference if you dyno the 6MT in 5th gear and the 5AT in 4th gear. Both are in the 1:1 ratio and 4th gear on the 5AT is a lock-up gear so there is no slippage.

Both cars use the same engine and same driveshaft so there is no difference there.

The only significant difference is the 6MT comes with a slightly shorter FD than the 5AT. That slight difference will give the 6MT slightly higher peak hp at the high end.

On the low to mid end the 5AT has the advantage because of the torque converter and better torque management through torque multiplication. The 5AT doesn't need to have as many gears as the 6MT to stay in it's powerband. On the 5AT, 1st-3rd gear have variable gear ratios when the TC is unlocked. The listings you see on specs are the gear ratios when the gear is in its locked position. It would be impossible to list every gear ratio on an unlocked TC because they are infinetly variable. The 6MT needs more gears because it has fixed gear ratios. The 5AT doesn't need as many gears because the torque converter can adjust for torque automatically.

Here are some links on gearing and torque multiplication:

http://www.victrans.com/multiplication.html
Torque Multiplication Explained

http://www.datsuns.com/Tech/tech_gearing.htm
Gearing Explained

Aggro_Al

I've tried the manuever you described before with both the 6MT and the 5AT and I haven't noticed a difference. I felt I did better in the 5AT in full auto mode than I did driving the 6MT or the 5AT in manual mode. I was even rev-matching out of the turns with the 6MT. I know that I'm not the greatest driver around but I'm not too bad. You're probably a better driver than I am and can maximize the 6MT.

capnfrantic

Thank you Aggro_Al ! It may be me but I think the 6MT crowd needs to know they are truly faster/better? I'll take my chances in a curve with a 6MT. Yeah, I know there is no way I can keep up...... Seriously I don't see that much difference. Yes I have driven both cars. It did'nt take the theory of transmission evolution to know I was'nt losing much to the 6MT. JMO

sentry65

iTrader: (11)

I originally had a 2004.5 5AT Z entusiast and loved it.

After 4 months, I traded it in for a 2003 track model 6MT Z. I love it too

I'm not a pro manual driver. And actually have only been driving stick for about 5 months now. I still feel I have a lot to learn about driving smoother - (this is further amplified by the current mods I have)

But I really like driving the manual. It's just more fun. Even if I can't shift as fast as the auto, it feels faster just from the shifting itself. I like being able to rev match when downshifting - sounds a lot more mean than the auto downshifting. I also really like being able to rev my engine at any time - especially with the tilton and UR pulley.

I like being able to do burn outs easily.

I miss the auto sometimes though. Sometimes I just want to get somewhere and dealing with a manual in traffic can get annoying at times. It's especially so with the tilton.

The 6 speed is going to be easier to mod and it'll hold more power from what I understand. I however really love the Z's auto gearbox with how fast it shifts and how well the ECU deals with shifting. The Z's auto is way better than the corvette's auto IMO. The 05 Z's are probably even better with the revmatching feature now, though haven't driven one myself.