Thanks Clint for finally posting a reply to my original question. There seems to have been great faith placed in Nissan Press Releases versus the actual specs. listed on the updated Infiniti website. Again, I found it suspicious that Infiniti would update ALL other aspects of the site with revised 2005 specs. (brake rotor diameters, weights, etc.) but somehow overlook a rather major engine upgrade. It was also enlightening to read your '04 MT vs. AT hypothesis. Given what I personally saw on our Nor. Cal. dyno day (and other results posted), it sounds very plausible (that Sedan MT's always had 280hp).

Perhaps there is a good reason for <'04 ATs to have different timing maps. Specifically, they might well run better on non-premium fuel. My 04.5 MT Sedan with ULEV-II pings under WOT if I use <91 octane.

It's been covered IN DETAIL already, but my $0.02 on 2005 diffs...
I don't find myself reving often to >6000rpm - especially with the Stillen exhaust (draws WAY too much attention). Since HP = TQ * RPM/5252 (remember dyno's measure TQ directly and compute HP), maintaining torque at a higher RPM gives you a higher peak HP (which is what is reported as 298). How this relates to "real-world" driving is a function of how you drive AND what the TQ curve looks like. It seems very plausible that VVT on the exhaust has allowed Nissan to broaden the TQ curve and thus get a peak HP boost. That the '05 AT's don't have exhaust VVT is probably not going to change any potential buyer's mind about the age old AT vs. MT question!

 

That's the first time I read 'variable exhaust timing' and 'AT sedan' in the same sentence. Although, that is not to imply I have seen all the articles out there. Would you provide a link to the above quote? Thanks.

That was in reference to the following quote:

"A pressure valve automatically opens the exhaust flow wide at higher rpm to boost high-end power output and gives the G35 the growl of a hot rod. When rpm is reduced, as during idle, the valve adjusts to hush the muffler to nothing more than a soothing hum"

... which is not to be confused with Engine Exhaust Valve timing.


This is the *official* Nissan press-release on the new VQ (which is identical to the '05 6mt-spec G35):

"The 35th Anniversary Z®’s engine has been modified using revised pistons and camshaft and the addition of electronic exhaust valve timing control. The same engine will also be available as standard equipment on the 2005 350Z Track model (6MT only), which also goes on sale in early 2005."

Not even the AT model 350Zs get variable exhaust timing.

Finally, it is clearly outlined in the '05 Service Manual ... showing TWO different implementations of the engine ... one w. the addition of the Variable Exhaust Timing ... the other not.


I hope that helps.

Cheers,

 

So whats it going to take to get my 04.5 to 280 hp & 270 lb-ft tq? Sounds like a simple ECU adjustment from the dealer?

 

Thats what I think. The engine and everything is the same betw/ the 04 and 05. I am no expert or anything, but I think it is an ECU adjustment as well.

 

Read Clint's post[s] again. The AT does not have the variable timing on the exhaust side, so no. Much more than an ECU adjustment.



On another, related note, I've kind of convinced myself also that for 2005 they redesigned the stock plenum so as not to be so restrictive. Does anyone have access to both an 04 and an 05 to prove or disprove my theory?

 

Here's the link to the article I was shown as to the indication of the Variable Exhaust Valve timing. Nissan press release

I know that it may be miswording on their part, but from what I translated in that article was that the 5AT sedan did get Exhaust VVT.

Not trying to argue, but just stating what I understood by what I read.

 

Ok folks ... stand by. I may be onto something here.

 

You can't just leave us hanging like that!

 

doogie, read G4me's post again. He was wondering how he could get his '04.5 to 280 hp and 270 tq like the '05 ATs. He's not talking about the '05 6MTs.

 

ah rgr that. Sorry. Brain fart.

Anyone have any info on the plenums?

 

Sorry ... I didn't mean to keep you all in the dark. I had meetings up the wazoo that prevented me from coming back for a reply.

Sirwrenchsalot,
Thanks for the link. No need to defend yourself. I was simply curious to read the article in its entirety and having done so, I would have drawn the same exact conlusion (as you). It was certainly misleading and definitely looked to be a cut 'n paste error by the marketing/web dude. This wouldn't have been their first time either ... remembering conflicting info regarding Brembo and SAT radio back in the days. Also note, the particular article is not an official *press-release*. It is simply an article on the *official* Nissan/Infiniti website. I recognized many references recycled from the *official press-release* itself. It was only a matter of time that such error(s) exists when you let people lacking the proper background knowledge to generate a whole new document by reshuffling words from another.


Here's to indulge the rest. I've attached a portion of the '05 ECM pin-out schematic. Circled in red are related to the *new* Exhaust Variable Valve Timing mechanism (not present in the 03-04 schematic of course). The 'M' designator on the schematic applies to 'Manual Transmission' models ONLY.


Cheers,

 

No worries, some of us actually have jobs to do and others, like myself, pretend we do.

Great job on the ECM schematic. This is hard evidence and should put to rest anymore doubts regarding this subject.

 

The variable valve timing does have an effect and if you want it on your pre 05 cars their are aftermarket manufaccturers that sell them (before the 05 was released) with almost identical hp/ torque gains. I believe JWT has one that will mimick the 280hp/270lb-ft of the AT and I can't remember who does the extra 38 hp gain liek the 6MT. Getting tired mind not functioning sooo good (maybe too much crown) will sleep it off and when I remember get back to y'all

Good Day Eh