I don't get it. Anyway, I've been driving manual for as long as I've started driving (about 13+ years). I am considering "maybe" getting an automatic as my next car. However, what I don't get is, especially in US, where majority of the cars sold are automatic. Doesn't it make sense for Infiniti to make auto and manual the same horses for 05 model? Bmw, Lexus, Acura, or whatever cars always make auto/manual with the same horses, doesn't it?

 

Acura's NSX automatic models have considerably less HP.

I think it's ok, people driving stick are probably willing to always use premium fuel so they can make that a requirement; they can probably live with a rougher/noisier engine. Additionally most car magazines still review 6spd models and they're very performance oriented. Now they'll be able to kill reviews and still keep the major target audience 40-50 year olds happy with a luxury minded car.

04 6MT Sedan - Z Tube, K&N Drop-In, 04 Z Suspension

 

There's another factor, too. The auto engine is tuned to be driven best by an automatic transmission. The manual engine is tuned to be driven best by a manual. This was just explained to me this week by a Nissan engineer. I will do my best to repeat what he told me:

Look at the torque numbers. The auto engine makes 270 pound-feet at a lower rpm; the manual makes only 260 at a higher rpm. With an auto trans, you want that powerful push of torque to be down low, and to have a broad powerband. That will make the car feel fastest (and be fastest when not held in gear to redline). But when you drive that same engine with a manual, you encounter a low redline and no peaky burst of power at high rpms. So it doesn't *feel* as fast as it could. It's not as fun to drive. When you take that car to the track, you won't wring every bit of power out of it.

So they retuned the 6MT's engine so it's peakier and has a higher redline. Thus, you can wind it out, it makes lots of power up top, it feels faster and more exciting to drive, and (I think - can't be sure) it will actually be faster when driven all out.

I think they did the right thing. They are not playing favorites. Every G35 owner will have the fastest-feeling car, be it auto or manual! I like their attitude.

 

I'm sorry Johnny but you're not making any sense.

First of all, both cars peak torque number comes at 4800 rpm.

Also, what do you mean by "encountering a low redline and no burst of power at high rpms with a manual"? The 298hp comes at 6400rpm for the manual. 280hp @ 6200 for the auto.

 

Hmmm...sorry about being confusing. If your numbers are right, then obviously I am not making much sense.

Here is how the conversation went:

Me: How come the auto doesn't get the 298 horses like the 6MT?
Him: Even though the engine was tuned well, it didn't *feel* fast enough to the driver. Other cars felt faster even though ours was faster. So we retuned it so that the engine made more power up top. The auto still makes more torque, which is what you want when driving an auto. But the manual now has a higher redline, which is more fun to drive and feels faster. Plus, when you take the manual to the track, it will be faster with the higher horsepower.
Me: Asks for some more detailed explanation.
Him: Tells me stuff that I am not good at repeating because I don't understand the technical part well enough.

If there's any follow-up question I can ask him, let me know and I will do so. He's a good friend but will not tell me things that are secret or are under wraps. But he will tell me things that clarify things that the public already knows.

 

Ok, now that makes more sense.

It sounds as if he didn't answer your question of "why the auto didn't get 298". Instead, he answered the question of "why the 6MT did get 298". I guess it explains it either way.

 

Generally speaking, the outputs of the same engine for auto and manual are different because of the loss of hp in the auto tranny. The auto tranny is inherently inefficient of transmitting hp, thus the loss of hp.

2004 G35X

 

KingofRoad but that doesn't matter, their claims are crank HP (crank = before tranny).

What Johnny says makes perfect sense and that's what I assumed was the case.

298/260 (HP/TQ) compared to 280/270 isn't that substantial really. For an auto the added torque and broader power delivery is preferred. For manual it doesn't matter as much. Ideally a 298/290 6mt delivery would be the best, but they just couldn't get that out of the VQ35 with the modifications made. Basically they raised the redline, made it more of a top end engine while the auto just got more power without the loss.

It's safe to assume that the auto and probably 03-04 G35's (both sedan and coupe) will feel faster before 4000 RPM but have no where near the legs of the 298 HP G35's. It reminds me of the VQ30DE vs VQ30DE-K, the K was rated at 37 more HP but only had that advantage from 5000-6500 RPM. Before 5000 RPM, the 190 HP VQ30DE put out about 10 more HP throughout the curve. In a dead even race, the 190 HP was faster to 60, they were about the same to the 1/4 and the 227HP DE-K was faster from 0-100+. Albeit the cars with the DE-K weighed about 150-200 LBS more so factor that in as well, but we're not talking about a 37 HP jump, just an 18.

HP = (Torque * RPM) / 5,252
So torque is pretty important in determining how much power is delivered. For day to day driving the 280/270 engine (even in 6mt) would probably be preferable if not even faster for light to light driving. However, for all out racing the 298/260 configuration is optimal. It also gives Infiniti the advantage of saying their cars produce 298 HP compared to the TL's 270 (in 6mt configuration). 90% of magazines test manuals if available, so it's a double bonus for Infiniti.

04 6MT Sedan - Z Tube, K&N Drop-In, 04 Z Suspension

 

Could we add a couple 'go-fast' goodies to bring the auto numbers up to par with the manual? -thanks.

amG35
2003 Silver Sedan<P ID="edit"><FONT class="small"><EM>Edited by amg35 on 11/16/04 05:45 AM.</EM></FONT></P>

 

Johnny, The extra horsepower, it comes from changes to both the exhaust cam and the ECU. The salesman was correct in saying the Auto was tuned for an automatic and same for the manual. And yes the manual will be faster, every car magazine that has done testing on both generally has the manual 0.3 to 0.5 sec quicker than the auto. With the changes on the 05 this will only be exagerated.

What he told you wasn't wrong nor was it 100% correct. Basically everybody who has bought this car in 03-04 knew it had more potential and as soon as competition came out to challenge their hp they made small changes to ensure they had higher numbers for the magazines. What he didn't tell you was they did this on purpose, because it may make 03-04 owners feel taken advantage of. Its what car manufactures have to do to ensure longevity of a vehicle. If they had to release a brand new version of every car every year they would all go broke, so they have to play "the game".

If you want to ask him a follow up question ask him this:
"If Jack helped you off a horse, would you help Jack-off a horse?"

 

You can buy an 03 and add a plenum, z-tube and maybe some light exhaust mods and easily run with an 05 auto and most likely beat even an 05 stick. Despite the fact that the stick is faster - no doubt - most people can't or won't get the lauch right 95% of the time and as such on a track you'll be better off in the auto anyway.

As for 05 MT vs 05 AT, the differences will not be exagerated that much as the 03-04 MT were most likely underrated in the first place from different ECU maps. Which is why the some of the quarter mile differences were .2-.5 seconds between the two already - in the mags anyway.

2003.5 DP 5AT Sedan
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Hotchkis Sways (M/M)
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

And don't forget the 05 6MT is the portly one of the bunch. The additional 100 pounds in teh 05 plus the additional 50 the MT has is a good reason to go for the higher HP. It will be interesting to see the REAL results come in from mags and real world events. I'd say a modded lighter AT has all the potential of the 05 plus the added benefit of lower weight. My mods cost about the same as the price increase for each of the last 2 years. My leather is no where near as soft tho!

2003.5 DP 5AT Sedan
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Hotchkis Sways (M/M)
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

I never really understood why the 6MT is lighter than the 5AT in the G35. In every other car I've ever known of in the history of cars...the manual was lighter than the auto.

It's exactly 44 lbs heavier according to Infiniti's site. Could it be because the tranny has an extra gear? Plus, the 6MT comes with the sport-tuned suspension pkg. AFAIK, they beefed up the suspension on the 05 (e.g. larger diameter sway bars). Also, the 18" wheels + tires, vs 17" on the 5AT sedan.

CoMiNg SoOn
2005 G35 Sedan 6MT
Diamond Graphite/Graphite
Premium, Navigation, Splash Guards, Trunk mat

 

Im guessing that the wheels play a big part in the weight gain..

 

I am by no means a great driver and getting the perfect launch 5% sounds about right. But the extra 0.2-0.4 sec difference is a more of a major screw up on launch and shifting. I would think the average person who even tries to perfect his launching can still beat the AT most of the time. There aren't many G's in my area but according to most magazine times the Mustang GT's are similar (both At and Manual times) and the only one who I have not been able to beat was a manual (that's not exactly scientific testing or proof by the way) and that time we tied.

However, you do make a good point about the extra weight. Why does the manual carry the extra weight (as dirrtybear asks)??? The rotational mass of the manual should be lighter!! Other add ons for better track performance may be the answer for the added weight, this would mean that Infiniti is setting the 6MT up for comparison tests with other cars not the AT.

Sixfive - don't forget that a slightly modded 6MT will beat a slightly modded AT. You need to compare apples to apples. If I add that same plenum, z tube and light exhaust mods I can easily beat the 05 auto and 05 stick. Actually I will be very egotistical and say I could beat the 05 auto without any mods to my 03 6MT.

Sorry for the trash talk we should save that for other vehicles, so I will instead ask how you like your Polk's? I always thought the stereo could be made much better just by using better speakers. Does the 10 Wire Hyper-ground help clean up the back ground noise? What was your best mod? I would like to spend a little money on my first mod just not sure what (CAI, plenum, ECU reflash, new speakers...etc only thinking of spending $400).